698 results on '"von Segesser LK"'
Search Results
152. Type A dissection in young patients.
- Author
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Niclauss L, Delay D, and von Segesser LK
- Subjects
- Acute Disease, Adult, Age Factors, Aortic Dissection diagnostic imaging, Aortic Dissection surgery, Angiography methods, Aortic Aneurysm, Thoracic diagnostic imaging, Aortic Aneurysm, Thoracic surgery, Blood Vessel Prosthesis Implantation methods, Blood Vessel Prosthesis Implantation mortality, Cohort Studies, Female, Follow-Up Studies, Humans, Kaplan-Meier Estimate, Male, Retrospective Studies, Risk Assessment, Survival Analysis, Vascular Surgical Procedures methods, Vascular Surgical Procedures mortality, Young Adult, Aortic Dissection mortality, Aortic Aneurysm, Thoracic mortality, Cause of Death, Hospital Mortality trends
- Abstract
Objectives: Ascending aortic dissection still remains a poorly understood dramatic disease with unpredictable results for the patient in spite of all the cardiac surgeons' efforts. Mean age of disease onset generally is in the sixth decade and one decade earlier in the case of connective tissue abnormalities. Type A dissection among young patients (<40 years) remains rare. An isolated analysis of these patients may help to understand the pathology and identify risk factors and may show postoperative disease progression., Methods: From July 1968 to February 2009, 27 patients (22 men and five women) younger than 40 years old at admission were operated for acute or chronic type A dissection. A cross-sectional follow-up was done in December 2009 by phone interview and analysis of the most recent available echocardiography and/or CT-scan., Results: A connective tissue disease was causative in 46% and a bicuspid aortic valve (BAV) was found in 22% of the patients. Fourteen patients had a Bentall procedure and 13 patients a simple prosthetic ascending aortic replacement. Early in-hospital mortality was, with 11%, lower than the average early mortality rate. Twenty-six percent of patients developed neurological complications. During a mean follow-up of 117 months, 20 patients survived in good cardiac health (late mortality rate 8%). Aortic root dilatation was the main re-operation cause and occurred in almost 40% of patients after a simple prosthetic ascending aortic replacement., Conclusions: Predominant etiologies for type A dissection in young patients are connective tissue diseases, BAV, severe hypertension, vascular diseases and cocaine abuse. Early in-hospital mortality rate was low and principally influenced by massive myocardial infarction due to coronary dissection as well as severe neurological disorders. Aortic root dilatation after a prosthetic ascending aortic replacement was the main re-operation cause and occurred earlier during follow-up than arch or more distal aortic dilatation. Surgical ascending aortic repair for type A dissection in young patients is lifesaving with excellent long-term survival.
- Published
- 2011
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153. Aortic valve lesion after coronary angiography.
- Author
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Rolf T, Tozzi P, Roumy A, Iglesias JF, and von Segesser LK
- Subjects
- Acute Coronary Syndrome therapy, Acute Disease, Aortic Valve Insufficiency diagnostic imaging, Bioprosthesis, Cardiac Catheterization adverse effects, Cardiac Catheterization methods, Coronary Angiography methods, Echocardiography methods, Follow-Up Studies, Heart Valve Prosthesis Implantation methods, Humans, Male, Middle Aged, Risk Assessment, Severity of Illness Index, Treatment Outcome, Acute Coronary Syndrome diagnostic imaging, Aortic Valve Insufficiency etiology, Aortic Valve Insufficiency surgery, Coronary Angiography adverse effects, Iatrogenic Disease
- Abstract
A 56-year-old patient admitted to hospital for the suspicion of an acute coronary syndrome underwent coronary angiography without detection of significant lesions. Seven days later the echocardiography showed acute severe aortic valve insufficiency. Intraoperatively we found a perforated leaflet probably due to lesion during transcatheter procedure.
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- 2011
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154. WITHDRAWN: Transfemoral aortic valve-in-valve procedure with the new Edwards SAPIEN XT valve.
- Author
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Ferrari E, Eechkout E, Vogt P, and von Segesser LK
- Abstract
This article has been withdrawn at the request of the authors and Editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy., (Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)
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- 2011
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155. Transapical aortic valve implantation following a left pneumonectomy.
- Author
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Ferrari E, Sulzer C, Marcucci C, Qanadly SD, Locca D, Berdajs D, and von Segesser LK
- Subjects
- Aortic Valve Stenosis diagnostic imaging, Aortic Valve Stenosis etiology, Fluoroscopy, Humans, Lung Neoplasms complications, Lung Neoplasms radiotherapy, Lung Neoplasms surgery, Male, Middle Aged, Monitoring, Intraoperative, Peripheral Vascular Diseases complications, Risk, Severity of Illness Index, Tomography, X-Ray Computed, Aortic Valve Stenosis surgery, Heart Valve Prosthesis Implantation methods, Pneumonectomy
- Abstract
Transapical transcatheter aortic valve implantation is an emerging technique for high-risk patients with symptomatic aortic valve stenosis, peripheral vascular disease, and severe concomitant comorbidities. However, a previous major surgical intervention involving the left hemithorax and the lung has always been considered a technical surgical challenge or even a potential contraindication for this minimally invasive procedure. With this report, we demonstrate, for the first time, that a previous left pneumonectomy followed by mediastinal radiotherapy does not affect the feasibility of transapical transcatheter aortic valve implantation, and we discuss the preoperative workup and the peculiar intraoperative cardiac imaging and surgical assessment., (© 2010 Wiley Periodicals, Inc.)
- Published
- 2011
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156. Ultimate test bench for pediatric biventricular assist device based on artificial muscles.
- Author
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Muradbegovic M, Taub S, Rizzo E, von Segesser LK, and Tozzi P
- Subjects
- Age Factors, Artificial Organs, Biomechanical Phenomena, Child, Heart Failure physiopathology, Heart Failure surgery, Humans, In Vitro Techniques, Models, Cardiovascular, Muscles, Prosthesis Design, Software, Heart-Assist Devices statistics & numerical data
- Abstract
Ventricular assist devices (VADs) are used in treatment for terminal heart failure or as a bridge to transplantation. We created biVAD using the artificial muscles (AMs) that supports both ventricles at the same time. We developed the test bench (TB) as the in vitro evaluating system to enable the measurement of performance. The biVAD exerts different pressure between left and right ventricle like the heart physiologically does. The heart model based on child's heart was constructed in silicone. This model was fitted with the biVAD. Two pipettes containing water with an ultrasonic sensor placed on top of each and attached to ventricles reproduced the preload and the after load of each ventricle by the real-time measurement of the fluid height variation proportionally to the exerted pressure. The LabVIEW software extrapolated the displaced volume and the pressure generated by each side of our biVAD. The development of a standardized protocol permitted the validation of the TB for in vitro evaluation, measurement of the performances of the AM biVAD herein, and reproducibility of data.
- Published
- 2011
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157. The "dumbbell" technique for improved echocardiography-guided transapical aortic valve implantations.
- Author
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Ferrari E, Sulzer C, Marcucci C, and von Segesser LK
- Subjects
- Aortic Valve diagnostic imaging, Aortic Valve Stenosis diagnostic imaging, Humans, Stents, Ultrasonography, Interventional, Aortic Valve surgery, Aortic Valve Stenosis surgery, Echocardiography, Transesophageal, Heart Valve Prosthesis, Heart Valve Prosthesis Implantation methods
- Published
- 2010
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158. Therapy of acute massive pulmonary embolism associated with Klippel-Trenaunay syndrome.
- Author
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Niclauss L, Delay D, Ferrari E, Gersbach P, Stumpe F, and von Segesser LK
- Subjects
- Acute Disease, Adult, Female, Hemodynamics, Humans, Pulmonary Embolism diagnostic imaging, Pulmonary Embolism etiology, Pulmonary Embolism physiopathology, Pulmonary Embolism surgery, Shock, Cardiogenic etiology, Shock, Cardiogenic physiopathology, Shock, Cardiogenic therapy, Tomography, X-Ray Computed, Treatment Outcome, Vena Cava Filters, Young Adult, Cardiopulmonary Resuscitation, Embolectomy instrumentation, Klippel-Trenaunay-Weber Syndrome complications, Pulmonary Embolism therapy
- Abstract
Acute massive pulmonary embolism (PE) is a life-threatening event. Before the era of cardiopulmonary bypass, acute pulmonary embolectomy had been historically attempted in patients with severe hemodynamic compromise. The Klippel-Trenaunay syndrome (KTS) represents a significant life-long risk for major thromboembolic events. We present two young patients with Klippel-Trenaunay syndrome who survived surgical embolectomy after massive PE and cardiopulmonary resuscitation, with good postoperative recovery. Even though the role of surgical embolectomy in massive PE is not clearly defined, with current technology it can be life saving and can lead to a complete recovery, especially in young patients as described in this study., (Copyright © 2010 Annals of Vascular Surgery Inc. Published by Elsevier Inc. All rights reserved.)
- Published
- 2010
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159. Acute myocardial infarction caused by coronary embolization of a papillary fibroelastoma of the thoracic ascending aorta.
- Author
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Rolf T, Iglesias JF, Tozzi P, and von Segesser LK
- Subjects
- Aged, Aorta, Thoracic surgery, Coronary Angiography, Echocardiography, Transesophageal, Female, Fibroma pathology, Fibroma surgery, Humans, Treatment Outcome, Vascular Neoplasms pathology, Vascular Neoplasms surgery, Aorta, Thoracic pathology, Embolism etiology, Fibroma complications, Myocardial Infarction etiology, Neoplastic Cells, Circulating pathology, Vascular Neoplasms complications
- Abstract
Papillary fibroelastomas (PFE) are benign endocardial masses and generally originate from the cardiac valves, while PFE arising from the ascending thoracic aorta are an uncommon clinical finding. We report the case of a 78-year-old female who presented to the emergency department with an acute ST segment elevation myocardial infarction. Urgent coronary angiography showed no significant coronary artery obstructive disease but left ventriculography revealed the presence of a highly mobile mass located in the proximal portion of the ascending thoracic aorta. We postulated that the clinical symptoms were caused by embolization from the aortic mass and surgical excision of the peduncle was performed. Histopathological examination revealed a PFE with thrombotic material. Nowadays, surgical excision of PFE remains, the treatment of choice for symptomatic patients with excellent short- and long-term results but recurrence of PFE following surgical excision has not been reported.
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- 2010
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160. Intussusception like lesion after fenestration in aortic type B dissection.
- Author
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Rolf T, Qanadli SD, Rey J, and von Segesser LK
- Subjects
- Adult, Aortic Dissection diagnostic imaging, Aortic Dissection etiology, Aortic Aneurysm, Abdominal diagnostic imaging, Aortic Aneurysm, Abdominal surgery, Aortic Aneurysm, Thoracic diagnostic imaging, Aortic Aneurysm, Thoracic etiology, Aortography methods, Female, Humans, Intussusception diagnostic imaging, Intussusception surgery, Pregnancy, Pregnancy Complications, Cardiovascular diagnostic imaging, Pregnancy Complications, Cardiovascular etiology, Tomography, X-Ray Computed, Treatment Outcome, Vascular Surgical Procedures, Aortic Dissection therapy, Aortic Aneurysm, Abdominal etiology, Aortic Aneurysm, Thoracic therapy, Endovascular Procedures adverse effects, Intussusception etiology, Marfan Syndrome complications, Pregnancy Complications, Cardiovascular therapy
- Abstract
We report on a patient with Marfan syndrome who presented a Stanford type B dissection of the descending thoracic aorta in late pregnancy. After a cesarean section, the patient presented a severe obstruction of the mesenteric superior artery. An endovascular fenestration was performed (balloon and guidewire based fenestration). Computed tomography (CT) angiography revealed an intussusception 'like' image of the abdominal aortic layers as a consequence of the fenestration procedure. Because of aneurismal progression in the abdominal aorta, surgical repair of the abdominal aorta and intussusception material removal was achieved six weeks later. The patient is currently in good condition. We conclude that the intussusception could be induced by a guidewire. This fenestration procedure is not recommended in patients with structural aortic disorders.
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- 2010
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161. No arterial access: a 'blind flight' for a transapical aortic valve implantation.
- Author
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Ferrari E, Marcucci C, Sulzer C, Rizzo E, and von Segesser LK
- Subjects
- Angiography, Fluoroscopy, Humans, Male, Middle Aged, Treatment Outcome, Aortic Valve surgery, Aortic Valve Stenosis surgery, Heart Valve Prosthesis Implantation methods, Intraoperative Complications diagnostic imaging, Subclavian Steal Syndrome diagnostic imaging
- Published
- 2010
162. NEXT = new events in xurgical technology.
- Author
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von Segesser LK
- Subjects
- Diffusion of Innovation, Financial Support, Humans, Technology Assessment, Biomedical, Thoracic Surgical Procedures instrumentation, Thoracic Surgical Procedures trends
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- 2010
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163. Feasibility of transapical aortic valve implantation guided by intracardiac ultrasound without angiography.
- Author
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Ferrari E, Marcucci C, Di Bernardo S, and von Segesser LK
- Subjects
- Aged, Aortic Valve Stenosis diagnostic imaging, Fluoroscopy, Humans, Male, Treatment Outcome, Aortic Valve Stenosis therapy, Cardiac Catheterization, Heart Valve Prosthesis Implantation methods, Ultrasonography, Interventional
- Published
- 2010
- Full Text
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164. Successful transapical aortic valve implantation in a congenital bicuspid aortic valve.
- Author
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Ferrari E, Locca D, Sulzer C, Marcucci C, Rizzo E, Tozzi P, and von Segesser LK
- Subjects
- Humans, Male, Middle Aged, Aortic Valve abnormalities, Aortic Valve surgery, Heart Valve Prosthesis Implantation methods
- Abstract
Transcatheter stent-valve implantation in stenosed congenital bicuspid aortic valves is under debate. Heavily calcified elliptic bicuspid valves represent a contraindication to catheter-based valve therapies because of a risk of stent-valve displacement, distortion, or malfunctioning after the implantation. In this case report we illustrate our experience with a patient suffering from stenosed congenital bicuspid aortic valve who successfully underwent a transapical 26-mm Edwards Sapien stent-valve (Edwards Lifesciences Inc, Irvine, CA) implantation. Postoperative distortion, malfunctioning, and paravalvular leaks were not detected., (Copyright 2010 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
165. Primary isolated aortic valve surgery in octogenarians.
- Author
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Ferrari E, Tozzi P, Hurni M, Ruchat P, Stumpe F, and von Segesser LK
- Subjects
- Aged, 80 and over, Aortic Valve Insufficiency surgery, Aortic Valve Stenosis surgery, Bioprosthesis, Epidemiologic Methods, Female, Heart Valve Prosthesis, Heart Valve Prosthesis Implantation adverse effects, Humans, Male, Prosthesis Design, Treatment Outcome, Aortic Valve surgery, Heart Valve Prosthesis Implantation methods
- Abstract
Objectives: We reviewed our surgery registry, to identify predictive risk factors for operative results, and to analyse the long-term survival outcome in octogenarians operated for primary isolated aortic valve replacement (AVR)., Methods: A total of 124 consecutive octogenarians underwent open AVR from January 1990 to December 2005. Combined procedures and redo surgery were excluded. Selected variables were studied as risk factors for hospital mortality and early neurological events. A follow-up (FU; mean FU time: 77 months) was obtained (90% complete), and Kaplan-Meier plots were used to determine survival rates., Results: The mean age was 82+/-2.2 (range: 80-90 years; 63% females). Of the group, four patients (3%) required urgent procedures, 10 (8%) had a previous myocardial infarction, six (5%) had a previous coronary angioplasty and stenting, 13 patients (10%) suffered from angina and 59 (48%) were in the New York Heart Association (NYHA) class III-IV. We identified 114 (92%) degenerative stenosis, six (5%) post-rheumatic stenosis and four (3%) active endocarditis. The predicted mortality calculated by logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE) was 12.6+/-5.7%, and the observed hospital mortality was 5.6%. Causes of death included severe cardiac failure (four patients), multi-organ failure (two) and sepsis (one). Complications were transitory neurological events in three patients (2%), short-term haemodialysis in three (2%), atrial fibrillation in 60 (48%) and six patients were re-operated for bleeding. Atrio-ventricular block, myocardial infarction or permanent stroke was not detected. The age at surgery and the postoperative renal failure were predictors for hospital mortality (p value <0.05), whereas we did not find predictors for neurological events. The mean FU time was 77 months (6.5 years) and the mean age of surviving patients was 87+/-4 years (81-95 years). The actuarial survival estimates at 5 and 10 years were 88% and 50%, respectively., Conclusions: Our experience shows good short-term results after primary isolated standard AVR in patients more than 80 years of age. The FU suggests that aortic valve surgery in octogenarians guarantees satisfactory long-term survival rates and a good quality of life, free from cardiac re-operations. In the era of catheter-based aortic valve implantation, open-heart surgery for AVR remains the standard of care for healthy octogenarians., (Copyright 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.)
- Published
- 2010
- Full Text
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166. Which available transapical transcatheter valve fits into degenerated aortic bioprostheses?
- Author
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Ferrari E, Marcucci C, Sulzer C, and von Segesser LK
- Subjects
- Aged, 80 and over, Aortic Valve diagnostic imaging, Aortic Valve physiopathology, Aortic Valve Insufficiency diagnostic imaging, Aortic Valve Insufficiency etiology, Aortic Valve Insufficiency physiopathology, Echocardiography, Transesophageal, Female, Heart Valve Prosthesis Implantation adverse effects, Heart Valve Prosthesis Implantation methods, Hemodynamics, Humans, Prosthesis Design, Aortic Valve surgery, Aortic Valve Insufficiency therapy, Bioprosthesis, Cardiac Catheterization instrumentation, Heart Valve Prosthesis, Heart Valve Prosthesis Implantation instrumentation, Prosthesis Failure
- Abstract
The transapical transcatheter aortic valve implantation (TA-TAVI) in degenerated aortic bioprosthesis is an emerging therapy for surgically non-amenable patients. However, the presence of different types of aortic bioprostheses (stented and stentless), available in different sizes (19-27 mm), can be at the origin of important mismatches between the malfunctioning, degenerated aortic valves and the inner stent-valves implanted through transapical accesses (23 and 26 mm Edwards Sapien transcatheter stent-valves). We report an emergency TA-TAVI treatment of a severely regurgitant degenerated 23 mm Mitroflow aortic bioprosthesis (Sorin Group, Milano, Italy) implanted seven years earlier in an 80-year-old lady, and we reviewed the current available literature about transapical 'valve-in-valve' procedures to analyze the hemodynamic results and the ideal 'prosthesis-to-prosthesis' match.
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- 2010
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167. Superior venous drainage in the "LifeBox": a portable extracorporeal oxygenator with a self-expanding venous cannula.
- Author
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Berdajs D, Born F, Crosset M, Horisberger J, Künzli A, Ferrari E, Tozzi P, and von Segesser LK
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- Animals, Heart-Lung Machine, Oxygenators, Membrane, Swine, Venous Pressure, Cardiopulmonary Bypass instrumentation, Catheterization, Central Venous instrumentation, Extracorporeal Membrane Oxygenation instrumentation, Extracorporeal Membrane Oxygenation methods
- Abstract
Background: In an experimental setting, the performance of the LifeBox, a new portable extracorporeal membrane oxygenator (ECMO) system suitable for patient transport, is presented. Standard rectilinear percutaneous cannulae are normally employed for this purpose, but have limited flow and pressure delivery due to their rigid structure. Therefore, we aimed to determine the potential for flow increase by using self-expanding venous cannulae., Methods: Veno-arterial bypass was established in three pigs (40.6+/-5.1 kg). The venous line of the cardiopulmonary bypass was established by cannulation of the external jugular vein. The arterial side of the circulation was secured by cannulation of the common carotid artery. Two different venous cannulae (SmartCanula 18/36F 430mm and Biomedicus 19F) were examined for their functional integrity when used in conjunction with the centrifugal pump (500-3000 RPM) of the LifeBox system., Results: At 1500, 2000, 2500, and 3000 RPM, the blood flow increased steadily for each cannula, but remained higher in the self-expanding cannula. That is, the 19F rectilinear cannula achieved a blood flow of 0.93+/-0.14, 1.47+/-0.37, 1.9+/-0.68, and 1.5+/-0.9 l/min, respectively, and the 18/36F self-expanding cannula achieved 1.1+/-0.1, 1.9+/-0.33, 2.8+/-0.39 and 3.66+/-0.52 l/min. However, when tested for venous line pressure, the standard venous cannula achieved -29+/-10.7mmHg while the self-expanding cannula achieved -13.6 +/-4.3mmHg at 1500 RMP. As the RPM increased from 2500 to 3000, the venous line pressure accounted for -141.9+/-20 and -98+/-7.3mmHg for the 19F rectilinear cannula and -30.6+/-6.4 and -45+/-11.6mmHg for the self-expanding cannula., Conclusion: The self-expanding cannula exhibited superior venous drainage ability when compared to the performance of the standard rectilinear cannula with the use of the LifeBox. The flow rate achieved was approximately 40% greater than the standard drainage device, with a maximal pump flow recorded at 4.3l/min.
- Published
- 2010
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168. Seal properties of TachoSil: in vitro hemodynamic measurements.
- Author
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Berdajs D, Bürki M, Michelis A, and von Segesser LK
- Subjects
- Blood Loss, Surgical physiopathology, Drug Combinations, Equipment Failure, Equipment Failure Analysis, Humans, Hydrostatic Pressure, Materials Testing, Postoperative Hemorrhage physiopathology, Blood Loss, Surgical prevention & control, Fibrin Tissue Adhesive therapeutic use, Fibrinogen therapeutic use, Hemodynamics, Hemostatic Techniques instrumentation, Hemostatics therapeutic use, Postoperative Hemorrhage prevention & control, Surgical Sponges, Thrombin therapeutic use
- Abstract
Fibrin glue products and collagen patches are frequently used as a sealing product, preventing surgical side bleedings. This is especially true in the field of cardiovascular surgery, where increasing numbers of patients are being operated with antiplatelet and anticoagulation therapy. The aim of this report was, in an in vitro hemodynamic setting, to examine the sealant properties of the TachoSil (Nycomed Pharma, Linz, Austria) patch. Burst pressure and normal force of 15 TachoSil sealed defects were measured. This was determined in a closed hydraulic system. Mean burst pressure load for a 5-mm defect was 69+/-11.4 mmHg; for a 7-mm defect was 63+/-16 mmHg; and, 62+/-16 mmHg for the defect with a diameter of 10 mm (P>0.05). The mean calculated normal force was as follows: 0.91+/-0.15 N for the 5 mm defect, 6.5+/-1.6 N for the 7 mm, and 8.1+/-0.75 N for the 10 mm defect. The TachoSil patch has the capability to seal small defects. However, at the larger defects the seal character was significantly reduced. These results suggest that the device may be a good alternative for hemostasis for small defects. The capacity to curtail or stop hemorrhage at the larger defects is unlikely.
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- 2010
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169. eComment: Is there a need for the assisted venous drainage in the minimal invasive valve surgery.
- Author
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Berdajs DA and von Segesser LK
- Subjects
- Body Surface Area, Heart Valve Prosthesis Implantation adverse effects, Humans, Minimally Invasive Surgical Procedures, Patient Selection, Risk Assessment, Risk Factors, Treatment Outcome, Aortic Valve surgery, Assisted Circulation, Cardiopulmonary Bypass adverse effects, Catheterization, Central Venous, Heart Valve Prosthesis Implantation methods
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- 2010
- Full Text
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170. Transapical aortic valve implantation without angiography: proof of concept.
- Author
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Ferrari E, Sulzer C, Marcucci C, Rizzo E, Tozzi P, and von Segesser LK
- Subjects
- Aged, Aged, 80 and over, Female, Humans, Male, Middle Aged, Aortic Valve surgery, Aortic Valve Stenosis surgery, Heart Valve Prosthesis Implantation methods
- Abstract
Background: Cardiac computed tomographic scans, coronary angiograms, and aortographies are routinely performed in transcatheter heart valve therapies. Consequently, all patients are exposed to multiple contrast injections with a following risk of nephrotoxicity and postoperative renal failure. The transapical aortic valve implantation without angiography can prevent contrast-related complications., Methods: Between November 2008 and November 2009, 30 consecutive high-risk patients (16 female, 53.3%) underwent transapical aortic valve implantation without angiography. The landmarks identification, the stent-valve positioning, and the postoperative control were routinely performed under transesophageal echocardiogram and fluoroscopic visualization without contrast injections., Results: Mean age was 80.1 +/- 8.7 years. Mean valve gradient, aortic orifice area, and ejection fraction were 60.3 +/- 20.9 mm Hg, 0.7 +/- 0.16 cm(2), and 0.526 +/- 0.128, respectively. Risk factors were pulmonary hypertension (60%), peripheral vascular disease (70%), chronic pulmonary disease (50%), previous cardiac surgery (13.3%), and chronic renal insufficiency (40%) (mean blood creatinine and urea levels: 96.8 +/- 54 microg/dL and 8.45 +/- 5.15 mmol/L). Average European System for Cardiac Operative Risk Evaluation was 32.2 +/- 13.3%. Valve deployment in the ideal landing zone was 96.7% successful and valve embolization occurred once. Thirty-day mortality was 10% (3 patients). Causes of death were the following: intraoperative ventricular rupture (conversion to sternotomy), right ventricular failure, and bilateral pneumonia. Stroke occurred in one patient at postoperative day 9. Renal failure (postoperative mean blood creatinine and urea levels: 91.1 +/- 66.8 microg/dL and 7.27 +/- 3.45 mmol/L), myocardial infarction, and atrioventricular block were not detected., Conclusions: Transapical aortic valve implantation without angiography requires a short learning curve and can be performed routinely by experienced teams. Our report confirms that this procedure is feasible and safe, and provides good results with low incidence of postoperative renal disorders., (2010 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)
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- 2010
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171. Self-expanding mini-cannula for remote perfusion with pediatric scenarios.
- Author
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Berdajs DA, Bernandi E, Burki M, Hurni M, Tozzi P, Horisberger J, and von Segesser LK
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- Animals, Animals, Newborn, Blood Pressure, Cattle, Equipment Design, Humans, Infant, Models, Animal, Regional Blood Flow, Cardiac Surgical Procedures, Cardiopulmonary Bypass, Catheterization, Central Venous instrumentation, Jugular Veins physiology, Perfusion instrumentation
- Abstract
The aim of this report is to address the benefits of the minimal invasive venous drainage in a pediatric cardio surgical scenario. Juvenile bovine experiments (67.4+/-11 kg) were performed. The right atrium was cannulated in a trans-jugular way by using the self-expandable (Smart Stat, 12/20F, 430 mm) venous cannula (Smartcannula LLC, Lausanne, Switzerland) vs. a 14F 250 mm (Polystan Lighthouse) standard pediatric venous cannula. Establishing the cardiopulmonary bypass (CPB), the blood flows were assessed for 20 mmHg, 30 mmHg and 40 mmHg of driving pressure. Venous drainage (flow in l/min) at 20 mmHg, 30 mmHg, and 40 mmHg drainage load was 0.26+/-0.1, 0.35+/-0.2 and 0.28+/-0.08 for the 14F standard vs. 1.31+/-0.22, 1.35+/-0.24 and 1.9+/-0.2 for the Smart Stat 12/20F cannula. The 43 cm self-expanding 12/20F Smartcannula outperforms the 14F standard cannula. The results described herein allow us to conclude that usage of the self-expanding Smartcannula also in the pediatric patients improves the flow and the drainage capacity, avoiding the insufficient and excessive drainage. We believe that similar results may be expected in the clinical settings.
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- 2010
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172. Biometal muscle to restore atrial transport function in a permanent atrial fibrillation animal model: a potential tool in the treatment of end-stage heart failure.
- Author
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Tozzi P, Hayoz D, Taub S, Muradbegovic M, Rizzo E, and von Segesser LK
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- Animals, Atrial Fibrillation etiology, Atrial Fibrillation physiopathology, Atrial Function, Right physiology, Cardiac Output physiology, Disease Models, Animal, Equipment Design, Heart Atria pathology, Heart Atria physiopathology, Heart Failure complications, Heart Failure physiopathology, Hemodynamics physiology, Sheep, Trace Elements, Atrial Fibrillation therapy, Heart Failure therapy, Heart-Assist Devices, Pacemaker, Artificial
- Abstract
Background: Half of the patients with end-stage heart failure suffer from persistent atrial fibrillation (AF). Atrial kick (AK) accounts for 10-15% of the ejection fraction. A device restoring AK should significantly improve cardiac output (CO) and possibly delay ventricular assist device (VAD) implantation. This study has been designed to assess the mechanical effects of a motorless pump on the right chambers of the heart in an animal model., Methods: Atripump is a dome-shaped biometal actuator electrically driven by a pacemaker-like control unit. In eight sheep, the device was sutured onto the right atrium (RA). AF was simulated with rapid atrial pacing. RA ejection fraction (EF) was assessed with intracardiac ultrasound (ICUS) in baseline, AF and assisted-AF status. In two animals, the pump was left in place for 4 weeks and then explanted. Histology examination was carried out. The mean values for single measurement per animal with +/-SD were analysed., Results: The contraction rate of the device was 60 per min. RA EF was 41% in baseline, 7% in AF and 21% in assisted-AF conditions. CO was 7+/-0.5 l min(-1) in baseline, 6.2+/-0.5 l min(-1) in AF and 6.7+/-0.5 l min(-1) in assisted-AF status (p<0.01). Histology of the atrium in the chronic group showed chronic tissue inflammation and no sign of tissue necrosis., Conclusions: The artificial muscle restores the AK and improves CO. In patients with end-stage cardiac failure and permanent AF, if implanted on both sides, it would improve CO and possibly delay or even avoid complex surgical treatment such as VAD implantation., (Copyright (c) 2009 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.)
- Published
- 2010
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173. Daily reoxygenation decreases myocardial injury and improves post-ischaemic recovery after chronic hypoxia.
- Author
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Milano G, Corno AF, Samaja M, Morel S, Vassalli G, and von Segesser LK
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- Animals, Body Weight, Chronic Disease, Hematocrit, Hemoglobins metabolism, Hypoxia blood, Hypoxia physiopathology, Male, Myocardial Infarction pathology, Myocardial Infarction prevention & control, Myocardial Reperfusion Injury blood, Nitrates blood, Nitric Oxide Synthase Type III blood, Nitrites blood, Phosphorylation, Rats, Rats, Sprague-Dawley, Hypoxia complications, Myocardial Reperfusion Injury etiology, Myocardial Reperfusion Injury prevention & control, Oxygen Consumption physiology
- Abstract
Objective: In contrast to the clinical evidence, experimental studies showed that chronic hypoxia (CH) confers a certain degree of protection against ischaemia-reperfusion damage. We studied the effects of daily reoxygenation during CH (CHReox) on hearts exposed to ischaemia-reperfusion. We also separated the intrinsic effects on the myocardium of CH and CHReox from those related to circulatory and nervous factors., Methods: Fifty-one Sprague-Dawley rats were maintained for 15 days under CH (10% O(2)) or CHReox (10% O(2)+1 h day(-1) exposure to air). Normoxic (N, 21% O(2)) rats were the control. The animals were randomly assigned to one of the three following protocols: (1) protocol A: hearts (n=7 per group) were subjected to 30-min occlusion of the left anterior descending (LAD) coronary artery followed by 3-h reperfusion, with measurement of the injury by tetrazolium staining; (2) protocol B: the end-diastolic pressure (EDP) and left ventricular developed pressure x heart rate (LVDP x HR) were measured in Langendorff-perfused isolated hearts (n=5 per group) during 30-min global ischaemia and 45-min reperfusion; and (3) protocol C: hearts (n=5 per group) were frozen for the determination of levels of endothelial nitric oxide synthase (eNOS) by Western blotting., Results: CHReox hearts displayed greater phosphorylation of the eNOS and enhanced plasma level of nitrates and nitrites in comparison to CH hearts (P<0.0001, Bonferroni's post-test). The infarct size was greater in CH than in N hearts (P<0.0001, Bonferroni's post-test) while it was reduced in CHReox in comparison to CH and N hearts (P<0.0001). At the end of reperfusion, EDP was higher in CH than CHReox and N hearts (P=0.01, Bonferroni's post-test) while LVDP x HR was higher in CHReox and N than in CH hearts (P=0.03, Bonferroni's post-test)., Conclusions: Exposure to CH results in impairment of myocardial tolerance to ischaemia-reperfusion, greater injury and reduced recovery of performance, in agreement with clinical evidence. Infarct size, diastolic contracture and myocardial performance have been reduced, respectively, by 63%, 64% and 151% with daily reoxygenation compared with chronic hypoxia by accelerating intrinsic adaptive changes., (Copyright (c) 2009 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.)
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- 2010
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174. The European Board of Cardiovascular Perfusion adopts Interactive CardioVascular and Thoracic Surgery as its official publication.
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von Segesser LK
- Subjects
- Europe, Humans, Societies, Medical, Cardiology, Perfusion, Periodicals as Topic
- Published
- 2010
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175. Translation to success of surgical innovation.
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Vecht JA, von Segesser LK, Ashrafian H, Rao C, Skapinakis P, Saso S, Darzi A, and Athanasiou T
- Subjects
- Financial Support, Health Care Sector, Humans, Intellectual Property, Patents as Topic, Technology Assessment, Biomedical legislation & jurisprudence, Translational Research, Biomedical economics, Translational Research, Biomedical methods, Technology Transfer, Thoracic Surgical Procedures instrumentation
- Abstract
Contemporary thoracic and cardiovascular surgery uses extensive equipment and devices to enable its performance. As the specialties develop and new frontiers are crossed, the technology needs to advance in a parallel fashion. Strokes of genius or problem-solving brain-storming may generate great ideas, but the metamorphosis of an idea into a physical functioning tool requires a lot more than just a thinking process. A modern surgical device is the end-point of a sophisticated, complicated and potentially treacherous route, which incorporates new skills and knowledge acquisition. Processes including technology transfer, commercialisation, corporate and product development, intellectual property and regulatory routes all play pivotal roles in this voyage. Many good ideas may fall by the wayside for a multitude of reasons as they may not be marketable or may be badly marketed. In this article, we attempt to illuminate the components required in the process of surgical innovation, which we believe must remain in the remit of the modern-day thoracic and cardiovascular surgeon., (Copyright (c) 2009 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.)
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- 2010
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176. Phosphorylation of phosphatidylinositol-3-kinase-protein kinase B and extracellular signal-regulated kinases 1/2 mediate reoxygenation-induced cardioprotection during hypoxia.
- Author
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Milano G, von Segesser LK, Morel S, Joncic A, Bianciardi P, Vassalli G, and Samaja M
- Subjects
- Animals, Chromones pharmacology, Enzyme Inhibitors pharmacology, Flavonoids pharmacology, Male, Morpholines pharmacology, Perfusion, Phosphorylation, Rats, Rats, Sprague-Dawley, Reperfusion Injury, Extracellular Signal-Regulated MAP Kinases metabolism, Hypoxia pathology, Oxygen metabolism, Phosphatidylinositol 3-Kinases metabolism, Proto-Oncogene Proteins c-akt metabolism
- Abstract
In vivo exposure to chronic hypoxia (CH) depresses myocardial performance and tolerance to ischemia, but daily reoxyenation during CH (CHR) confers cardioprotection. To elucidate the underlying mechanism, we tested the role of phosphatidylinositol-3-kinase-protein kinase B (Akt) and p42/p44 extracellular signal-regulated kinases (ERK1/2), which are known to be associated with protection against ischemia/reperfusion (I/R). Male Sprague-Dawley rats were maintained for two weeks under CH (10% O(2)) or CHR (as CH but with one-hour daily exposure to room air). Then, hearts were either frozen for biochemical analyses or Langendorff-perfused to determine performance (intraventricular balloon) and tolerance to 30-min global ischemia and 45-min reperfusion, assessed as recovery of performance after I/R and infarct size (tetrazolium staining). Additional hearts were perfused in the presence of 15 micromol/L LY-294002 (inhibitor of Akt), 10 micromol/L UO-126 (inhibitor of ERK1/2) or 10 micromol/L PD-98059 (less-specific inhibitor of ERK1/2) given 15 min before ischemia and throughout the first 20 min of reperfusion. Whereas total Akt and ERK1/2 were unaffected by CH and CHR in vivo, in CHR hearts the phosphorylation of both proteins was higher than in CH hearts. This was accompanied by better performance after I/R (heart rate x developed pressure), lower end-diastolic pressure and reduced infarct size. Whereas the treatment with LY-294002 decreased the phosphorylation of Akt only, the treatment with UO-126 decreased ERK1/2, and that with PD-98059 decreased both Akt and ERK1/2. In all cases, the cardioprotective effect led by CHR was lost. In conclusion, in vivo daily reoxygenation during CH enhances Akt and ERK1/2 signaling. This response was accompanied by a complex phenotype consisting in improved resistance to stress, better myocardial performance and lower infarct size after I/R. Selective inhibition of Akt and ERK1/2 phosphorylation abolishes the beneficial effects of the reoxygenation. Therefore, Akt and ERK1/2 have an important role to mediate cardioprotection by reoxygenation during CH in vivo.
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- 2010
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177. Clinical review: practical recommendations on the management of perioperative heart failure in cardiac surgery.
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Mebazaa A, Pitsis AA, Rudiger A, Toller W, Longrois D, Ricksten SE, Bobek I, De Hert S, Wieselthaler G, Schirmer U, von Segesser LK, Sander M, Poldermans D, Ranucci M, Karpati PC, Wouters P, Seeberger M, Schmid ER, Weder W, and Follath F
- Subjects
- Humans, Predictive Value of Tests, Prognosis, Cardiac Surgical Procedures, Heart Failure etiology, Perioperative Care organization & administration, Practice Guidelines as Topic
- Abstract
Acute cardiovascular dysfunction occurs perioperatively in more than 20% of cardiosurgical patients, yet current acute heart failure (HF) classification is not applicable to this period. Indicators of major perioperative risk include unstable coronary syndromes, decompensated HF, significant arrhythmias and valvular disease. Clinical risk factors include history of heart disease, compensated HF, cerebrovascular disease, presence of diabetes mellitus, renal insufficiency and high-risk surgery. EuroSCORE reliably predicts perioperative cardiovascular alteration in patients aged less than 80 years. Preoperative B-type natriuretic peptide level is an additional risk stratification factor. Aggressively preserving heart function during cardiosurgery is a major goal. Volatile anaesthetics and levosimendan seem to be promising cardioprotective agents, but large trials are still needed to assess the best cardioprotective agent(s) and optimal protocol(s). The aim of monitoring is early detection and assessment of mechanisms of perioperative cardiovascular dysfunction. Ideally, volume status should be assessed by 'dynamic' measurement of haemodynamic parameters. Assess heart function first by echocardiography, then using a pulmonary artery catheter (especially in right heart dysfunction). If volaemia and heart function are in the normal range, cardiovascular dysfunction is very likely related to vascular dysfunction. In treating myocardial dysfunction, consider the following options, either alone or in combination: low-to-moderate doses of dobutamine and epinephrine, milrinone or levosimendan. In vasoplegia-induced hypotension, use norepinephrine to maintain adequate perfusion pressure. Exclude hypovolaemia in patients under vasopressors, through repeated volume assessments. Optimal perioperative use of inotropes/vasopressors in cardiosurgery remains controversial, and further large multinational studies are needed. Cardiosurgical perioperative classification of cardiac impairment should be based on time of occurrence (precardiotomy, failure to wean, postcardiotomy) and haemodynamic severity of the patient's condition (crash and burn, deteriorating fast, stable but inotrope dependent). In heart dysfunction with suspected coronary hypoperfusion, an intra-aortic balloon pump is highly recommended. A ventricular assist device should be considered before end organ dysfunction becomes evident. Extra-corporeal membrane oxygenation is an elegant solution as a bridge to recovery and/or decision making. This paper offers practical recommendations for management of perioperative HF in cardiosurgery based on European experts' opinion. It also emphasizes the need for large surveys and studies to assess the optimal way to manage perioperative HF in cardiac surgery.
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- 2010
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178. Unexpected left ventricular free-wall rupture following an aortic catheter-valve implantation.
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Ferrari E, Rizzo E, Sulzer C, and von Segesser LK
- Subjects
- Aged, 80 and over, Blood Loss, Surgical, Female, Heart Valve Prosthesis Implantation methods, Humans, Aortic Valve Stenosis surgery, Heart Rupture etiology, Heart Valve Prosthesis Implantation adverse effects
- Abstract
Our experience with the Sapien trans-apical aortic valve (Edwards Lifesciences Inc., Irvine, CA, USA) has been straightforward without per-procedural mortality except in 1/16 consecutive cases who developed non-apical haemorrhage early after valve implantation. We describe the case of an 84-year-old female carrying a very high operative risk (logistic EuroScore of 44%), who underwent a trans-apical stent-valve implantation for severe and symptomatic aortic valve stenosis (23 mm). Due to massive blood loss, an emergency sternotomy and cannulation for cardiopulmonary bypass resuscitation were necessary to treat (without success) an unusual and unexpected subaortic left ventricular free-wall rupture that occurred few minutes after the stent-valve positioning and implantation. To the best of our knowledge, this is the first described case of a left ventricular free-wall rupture occurring after an otherwise non-complicated standard catheter-based aortic valve replacement., (Copyright 2009 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.)
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- 2010
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179. Surgical glues: are they really adhesive?
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Perrin BR, Dupeux M, Tozzi P, Delay D, Gersbach P, and von Segesser LK
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- Adhesiveness, Animals, Cyanoacrylates pharmacology, Horses, Materials Testing instrumentation, Materials Testing methods, Pericardium drug effects, Pressure, Stress, Mechanical, Tissue Adhesives pharmacology, Cyanoacrylates chemistry, Tissue Adhesives chemistry
- Abstract
Objective: The aim of this study is to create a standard test to approve the efficacy of a surgical sealant. An industrial test, the bulge-and-blister test, which is very convenient for measuring adhesion energy, is applied to the surgical field to quantify adhesion of bioadhesives., Methods: Samples were composed of two circular layers of equine pericardium glued by the surgical sealant studied. The sample was fixed to a support with an industrial glue. The support and the bottom layer were perforated in the centre to allow injection of pressurised water. Water was progressively introduced through the hole in the support and the bottom layer to create a blister with constant radius, increasing height and internal pressure during this first step. At a critical pressure, delamination started, the radius and height of the blister increased and the pressure decreased. At this point, the adhesion energy could be determined. The experimental parameters were measured with a pressure sensor and an optical profilometry device for deflection., Results: Adhesion testing was carried out in eight paired equine pericardium samples bonded with a Dermabond cyanoacrylate glue. The average value of the practical adhesion energy is 2.3 Jm(-2) with a standard deviation of 1.5 Jm(-2)., Conclusion: Application of the bulge-and-blister test to the surgical field was achieved and allowed a quantification of adhesion of a surgical glue. Such information is essential to compare the different surgical glues presently available. The study of the impact of bonding conditions such as pressure, hygrometry or setting conditions will provide a better understanding of the characteristics of adhesion in the surgical field.
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- 2009
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180. A fully echo-guided trans-apical aortic valve implantation.
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Ferrari E, Sulzer C, Rizzo E, and von Segesser LK
- Subjects
- Aged, 80 and over, Aortic Valve diagnostic imaging, Aortic Valve Stenosis complications, Aortic Valve Stenosis diagnostic imaging, Female, Humans, Renal Insufficiency, Chronic complications, Ultrasonography, Interventional methods, Aortic Valve surgery, Aortic Valve Stenosis surgery, Heart Valve Prosthesis Implantation methods
- Abstract
The trans-apical aortic valve implantation (TA-AVI) is an established technique for high-risk patients requiring aortic valve replacement. Traditionally, preoperative (computed tomography (CT) scan, coronary angiogram) and intra-operative imaging (fluoroscopy) for stent-valve positioning and implantation require contrast medium injections. To preserve the renal function in elderly patients suffering from chronic renal insufficiency, a fully echo-guided trans-catheter valve implantation seems to be a reasonable alternative. We report the first successful TA-AVI procedure performed solely under trans-oesophageal echocardiogram control, in the absence of contrast medium injections.
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- 2009
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181. Experience and intermediate-term results using the Contegra heterograft for right ventricular outflow reconstruction in adults.
- Author
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Niclauss L, Delay D, Hurni M, and von Segesser LK
- Subjects
- Adolescent, Adult, Animals, Blood Vessel Prosthesis Implantation adverse effects, Cardiopulmonary Bypass, Cattle, Echocardiography, Feasibility Studies, Female, Heart Defects, Congenital diagnostic imaging, Heart Defects, Congenital physiopathology, Heart Valve Prosthesis Implantation adverse effects, Hemodynamics, Humans, Male, Middle Aged, Prosthesis Design, Reoperation, Sternotomy, Time Factors, Treatment Outcome, Young Adult, Bioprosthesis, Blood Vessel Prosthesis, Blood Vessel Prosthesis Implantation instrumentation, Heart Defects, Congenital surgery, Heart Valve Prosthesis, Heart Valve Prosthesis Implantation instrumentation, Jugular Veins transplantation, Venous Valves transplantation
- Abstract
Objectives: The Contegra bioprosthesis (valved heterologous bovine jugular vein) is used for reconstruction of the right ventricular outflow tract (RVOT) in congenital heart malformations and pulmonary valve replacement in different settings. Compared to pulmonary homografts, the Contegra conduit is readily available 'on the shelf'. So far, its use was mainly described in children. The aim of this study is to evaluate the feasibility and the outcome of Contegra graft implantation in the adult., Methods: Between November 1999 and December 2007, a total of 32 Contegra grafts were implanted in 31 patients (24 men and 7 women), with a mean age of 35.7+/-10.5 years (range 18-54 years). All operations have been completed through median sternotomy with cardiopulmonary bypass. Indications included: Ross procedure for aortic valve disease (n=22); re-operation of corrected Fallot-tetralogy (n=5); isolated pulmonary valve disease (n=2); re-operation of double outlet right ventricle (DORV) (n=1); pulmonary stenosis in congenital dilated cardiomyopathy (DCM) (n=1). Conduit sizes included 22 mm (n=31), 20 mm (n=1)., Results: There was no hospital mortality and no valved conduit related early morbidity. In the median follow-up of 38 months (range 1-99 months) of 28 patients there was one late death, not conduit related (total mortality 3.6%). Re-operation for symptomatic graft stenosis was realised in two patients, 7 and 16 months after primo-implantation, corresponding to graft related late morbidity of 7.1%., Conclusions: In this small review of 32 operations using the Contegra graft for RVOT reconstruction in adult cardiac surgery for different indications, we observed good postoperative mid-term results concerning conduit function. Mean transpulmonary pressure gradients remain low (13.3+/-6.6 mmHg postoperative, 14.5+/-7.9 mmHg at follow-up). The use of the Contegra graft seems to be a good alternative to the homograft with low operative mortality and morbidity. Long-term outcome data are not available and further investigations must be performed to evaluate results.
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- 2009
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182. Towards no-scar cardiac surgery - minimally invasive access through umbilicus for aortic valve replacement.
- Author
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Kalejs M, Ferrari E, and von Segesser LK
- Subjects
- Animals, Blood Loss, Surgical prevention & control, Feasibility Studies, Fluoroscopy, Heart Valve Prosthesis Implantation instrumentation, Minimally Invasive Surgical Procedures instrumentation, Minimally Invasive Surgical Procedures methods, Radiography, Interventional methods, Sus scrofa, Umbilicus surgery, Video-Assisted Surgery methods, Aortic Valve surgery, Heart Valve Prosthesis Implantation methods
- Abstract
There is an ever-growing trend towards less-invasive procedures in all fields of medicine. We designed an animal study to prove the concept that trans-apical aortic valve replacement from an incision within the umbilicus through a single channel for instruments is feasible, which would be a major leap towards no-scar cardiac surgery. In three adult pigs, after creating a single 3-cm incision at a place where the human umbilicus would be, we introduced a 30F sheath through a tunnel created by an endoscopic vein-harvesting device up to the cardiac apex, through it and up to the left ventricle simulating the approach for trans-apical aortic valve replacement. We used a standard Amplatz nitinol occluder to seal the defect in ventricle wall later. The animals were followed up for 1h. Blood loss was minimal, and no tamponade occurred in any of the animals. In addition, we performed a test with water column static pressure to evaluate the impact of preclotting on the sealing properties of the occluders: 1 min flow-through was 2860+/-176 ml for the standard occluders and 348+/-56 ml for preclotted occluders (p<0.001).
- Published
- 2009
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183. Superior flow for bridge to life with self-expanding venous cannulas.
- Author
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von Segesser LK, Kalejs M, Ferrari E, Bommeli S, Maunz O, Horisberger J, and Tozzi P
- Subjects
- Animals, Cattle, Emergencies, Equipment Design, Heart-Lung Machine, Venous Pressure, Cardiopulmonary Bypass instrumentation, Catheterization, Central Venous instrumentation
- Abstract
Background: Recently, a compact cardiopulmonary support (CPS) system designed for quick set-up for example, during emergency cannulation, has been introduced. Traditional rectilinear percutaneous cannulas are standard for remote vascular access with the original design. The present study was designed to assess the potential of performance increase by the introduction of next-generation, self-expanding venous cannulas, which can take advantage of the luminal width of the venous vasculature despite a relatively small access orifice., Methods: Veno-arterial bypass was established in three bovine experiments (69+/-10 kg). The Lifebridge (Lifebridge GmbH, Munich, Germany) system was connected to the right atrium in a trans-jugular fashion with various venous cannulas; and the oxygenated blood was returned through the carotid artery with a 17 F percutaneous cannula. Two different venous cannulas were studied, and the correlation between the centrifugal pump speed (1500-3900 RPM), flow and the required negative pressure on the venous side was established: (A) Biomedicus 19 F (Medtronic, Tolochenaz, Switzerland); (B) Smart canula 18 F/36 F (Smartcanula LLC, Lausanne, Switzerland)., Results: At 1500 RPM, the blood flow was 0.44+/-0.26 l min(-1) for the 19 F rectilinear cannula versus 0.73+/-0.34 l min(-1) for the 18/36 F self-expanding cannula. At 2500 RPM the blood flow was 1.63+/-0.62 l min(-1) for the 19F rectilinear cannula versus 2.13+/-0.34 l min(-1) for the 18/36 F self-expanding cannula. At 3500 RPM, the blood flow was 2.78+/-0.47 l min(-1) for the 19 F rectilinear cannula versus 3.64+/-0.39 l min(-1) for the 18/36 F self-expanding cannula (p<0.01 for 18/36 F vs 19 F). At 1500 RPM, the venous line pressure was 18+/-8 mmHg for the 19F rectilinear cannula versus 19+/-5 mmHg for the 18/36 F self-expanding cannula. At 2500 RPM the venous line pressure accounted for -22+/-32 mmHg for the 19 F rectilinear cannula versus 2+/-5 mmHg for the 18/36 F self-expanding cannula. At 3500 RPM, the venous line pressure was -112+/-42 mmHg for the rectilinear cannula versus 28+/-7 mmHg for the 18/36 F self-expanding cannula (p<0.01 for 18 F/36 F vs 19 F)., Conclusions: The negative pressure required to achieve adequate venous drainage with the self-expanding venous cannula accounts for approximately 31% of the pressure necessary with the 19 F rectilinear cannula. In addition, a pump flow of more than 4 l min(-1) can be achieved with the self-expanding design and a well-accepted negative inlet pressure for minimal blood trauma of less than 50 mmHg.
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- 2009
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184. Total aortic arch stenting--hemodynamical impact of carotid artery perfusion.
- Author
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Niclauss L and von Segesser LK
- Subjects
- Animals, Aorta, Thoracic diagnostic imaging, Blood Pressure, Brain Ischemia etiology, Brain Ischemia physiopathology, Catheterization adverse effects, Echocardiography, Feasibility Studies, Regional Blood Flow, Swine, Time Factors, Ultrasonography, Interventional, Aorta, Thoracic physiopathology, Brain Ischemia prevention & control, Carotid Arteries physiopathology, Catheterization instrumentation, Cerebrovascular Circulation, Hemodynamics, Perfusion, Stents
- Abstract
The aim of this experimental study is to evaluate the feasibility and the outcome of total endovascular stent implantation in the aortic arch. Indications for this operation-technique would be acute or chronic dissection of the aortic arch (non-A-non-B dissection) or type B dissection with retrograde extension. Four pigs were canulated via the distal abdominal aorta and a retrograde placement of a Djumbodis arch stent (4-9 cm) was controlled by using intravascular ultrasound and intracardiac ultrasound by the inferior cava vein and under radioscopic control. Cerebral perfusion, by using a flow meter placed on one prepared carotid artery, were controlled before, immediate post-procedural (<1 min), and in the early follow-up after aortic arch stent implantation. During the implantation process, especially during balloon inflation and deflation, mean carotid perfusion decreases slightly. A reactive increase of carotid perfusion after stent placements indicates transitory cerebral hypo-perfusion. Non-covered aortic arch stent implantation is technically feasible and could be a potential treatment option in otherwise inoperable arch dissections. The time required for balloon inflation and deflation causes an important risk of cerebral ischemia. The latter can be reduced by transaxillary perfusion.
- Published
- 2009
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185. Transcatheter stent-valve implantation in a stenotic pulmonary conduit via a sub-xyphoidian access.
- Author
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Ferrari E, Sulzer C, Rizzo E, and von Segesser LK
- Subjects
- Blood Vessel Prosthesis Implantation methods, Humans, Male, Pulmonary Valve abnormalities, Pulmonary Valve diagnostic imaging, Pulmonary Valve Stenosis diagnostic imaging, Reoperation, Stents, Tomography, X-Ray Computed, Ventricular Outflow Obstruction surgery, Young Adult, Heart Valve Prosthesis Implantation methods, Pulmonary Valve surgery, Pulmonary Valve Stenosis surgery
- Abstract
Patients who develop a severe stenosis in biological pulmonary conduits previously implanted for pulmonary outflow trunk reconstructions are treated either by surgical re-replacement, or by transcatheter stent-valve implantation through a femoral vein access. A catheter-based sub-xyphoidian access through the right ventricle for stent-valve positioning in a pulmonary conduit has rarely been proposed. We describe the case of a 20-year-old man who underwent a pulmonary trunk reconstruction for a congenital pulmonary valve dysplasia and a few years later developed a stenosis in the pulmonary conduit. He was successfully treated with a 23 mm Edwards Sapien stent-valve implantation in pulmonary position, through an unusual right ventricular, sub-xyphoidian access and without contrast medium injections and pleura opening.
- Published
- 2009
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186. Post-cardiac surgery arrest: what to do in the ICU (intensive care unit).
- Author
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von Segesser LK
- Subjects
- Coronary Care Units, Humans, Cardiac Surgical Procedures, Critical Care methods, Heart Arrest therapy, Postoperative Complications therapy
- Published
- 2009
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187. A new self-expanding aortic stent valve with annular fixation: in vitro haemodynamic assessment.
- Author
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Vergnat M, Henaine R, Kalejs M, Bommeli S, Ferrari E, Obadia JF, and Von Segesser LK
- Subjects
- Blood Pressure physiology, Heart Valve Prosthesis Implantation, Hemodynamics physiology, Humans, Minimally Invasive Surgical Procedures methods, Models, Cardiovascular, Prosthesis Design, Stents, Ventricular Pressure physiology, Aortic Valve surgery, Heart Valve Prosthesis
- Abstract
Objective: Balloon-expandable stent valves require flow reduction during implantation (rapid pacing). The present study was designed to compare a self-expanding stent valve with annular fixation versus a balloon-expandable stent valve., Methods: Implantation of a new self-expanding stent valve with annular fixation (Symetis, Lausanne, Switzerland) was assessed versus balloon-expandable stent valve, in a modified Dynatek Dalta pulse duplicator (sealed port access to the ventricle for transapical route simulation), interfaced with a computer for digital readout, carrying a 25 mm porcine aortic valve. The cardiovascular simulator was programmed to mimic an elderly woman with aortic stenosis: 120/85 mmHg aortic pressure, 60 strokes/min (66.5 ml), 35% systole (2.8 l/min)., Results: A total of 450 cardiac cycles was analysed. Stepwise expansion of the self-expanding stent valve with annular fixation (balloon-expandable stent valve) resulted in systolic ventricular increase from 120 to 121 mmHg (126 to 830+/-76 mmHg)*, and left ventricular outflow obstruction with mean transvalvular gradient of 11+/-1.5 mmHg (366+/-202 mmHg)*, systolic aortic pressure dropped distal to the valve from 121 to 64.5+/-2 mmHg (123 to 55+/-30 mmHg) N.S., and output collapsed to 1.9+/-0.06 l/min (0.71+/-0.37 l/min* (before complete obstruction)). No valve migration occurred in either group. (*=p<0.05)., Conclusions: Implantation of this new self-expanding stent valve with annular fixation has little impact on haemodynamics and has the potential for working heart implantation in vivo. Flow reduction (rapid pacing) is not necessary.
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- 2009
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188. A new training set-up for trans-apical aortic valve replacement.
- Author
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Abdel-Sayed P, Kalejs M, and von Segesser LK
- Subjects
- Aortic Valve pathology, Clinical Competence, Computer-Aided Design, Heart Valve Diseases pathology, Humans, Pulmonary Valve pathology, Pulmonary Valve surgery, Silicones, Aortic Valve surgery, Education, Medical, Graduate, Heart Valve Diseases surgery, Heart Valve Prosthesis Implantation education, Manikins, Models, Anatomic
- Abstract
Trans-apical aortic valve replacement (AVR) is a new and rapidly growing therapy. However, there are only few training opportunities. The objective of our work is to build an appropriate artificial model of the heart that can replace the use of animals for surgical training in trans-apical AVR procedures. To reduce the necessity for fluoroscopy, we pursued the goal of building a translucent model of the heart that has nature-like dimensions. A simplified 3D model of a human heart with its aortic root was created in silico using the SolidWorks Computer-Aided Design (CAD) program. This heart model was printed using a rapid prototyping system developed by the Fab@Home project and dip-coated two times with dispersion silicone. The translucency of the heart model allows the perception of the deployment area of the valved-stent without using heavy imaging support. The final model was then placed in a human manikin for surgical training on trans-apical AVR procedure. Trans-apical AVR with all the necessary steps (puncture, wiring, catheterization, ballooning etc.) can be realized repeatedly in this setting.
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- 2009
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189. Modalities and future prospects of gene therapy in heart transplantation.
- Author
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Vassalli G, Roehrich ME, Vogt P, Pedrazzini GB, Siclari F, Moccetti T, and von Segesser LK
- Subjects
- Gene Transfer Techniques, Genetic Therapy trends, Genetic Vectors, Graft Rejection immunology, Graft Rejection prevention & control, Humans, Inflammation Mediators metabolism, Lymphocyte Activation, T-Lymphocytes immunology, Genetic Therapy methods, Heart Transplantation
- Abstract
Heart transplantation is the treatment of choice for many patients with end-stage heart failure. Its success, however, is limited by organ shortage, side effects of immunosuppressive drugs, and chronic rejection. Gene therapy is conceptually appealing for applications in transplantation, as the donor organ is genetically manipulated ex vivo before transplantation. Localised expression of immunomodulatory genes aims to create a state of immune privilege within the graft, which could eliminate the need for systemic immunosuppression. In this review, recent advances in the development of gene therapy in heart transplantation are discussed. Studies in animal models have demonstrated that genetic modification of the donor heart with immunomodulatory genes attenuates ischaemia-reperfusion injury and rejection. Alternatively, bone marrow-derived cells genetically engineered with donor-type major histocompatibility complex (MHC) class I or II promote donor-specific hyporesponsiveness. Genetic engineering of naïve T cells or dendritic cells may induce regulatory T cells and regulatory dendritic cells. Despite encouraging results in animal models, however, clinical gene therapy trials in heart transplantation have not yet been started. The best vector and gene to be delivered remain to be identified. Pre-clinical studies in non-human primates are needed. Nonetheless, the potential of gene therapy as an adjunct therapy in transplantation is essentially intact.
- Published
- 2009
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190. Clinical databases--a double-edged sword!
- Author
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von Segesser LK
- Subjects
- Clinical Competence, Coronary Disease therapy, Humans, Databases, Factual, Thoracic Surgical Procedures standards
- Published
- 2009
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191. Valved stents for transapical pulmonary valve replacement.
- Author
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Huber CH, Hurni M, Tsang V, and von Segesser LK
- Subjects
- Feasibility Studies, Humans, Prosthesis Design, Heart Valve Prosthesis, Heart Valve Prosthesis Implantation methods, Pulmonary Valve surgery, Pulmonary Valve Insufficiency surgery, Stents
- Abstract
Objectives: Pulmonary valve insufficiency remains a leading cause for reoperations in congenital cardiac surgery. The current percutaneous approach is limited by the size of the access vessel and variable right ventricular outflow tract morphology. This study assesses the feasibility of transapical pulmonary valve replacement based on a new valved stent construction concept., Methods: A new valved stent design was implanted off-pump under continuous intracardiac echocardiographic and fluoroscopic guidance into the native right ventricular outflow tract in 8 pigs (48.5 +/- 6.0 kg) through the right ventricular apex, and device function was studied by using invasive and noninvasive measures., Results: Procedural success was 100% at the first attempt. Procedural time was 75 +/- 15 minutes. All devices were delivered at the target site with good acute valve function. No valved stents dislodged. No animal had significant regurgitation or paravalvular leaking on intracardiac echocardiographic analysis. All animals had a competent tricuspid valve and no signs of right ventricular dysfunction. The planimetric valve orifice was 2.85 +/- 0.32 cm(2). No damage to the pulmonary artery or structural defect of the valved stents was found at necropsy., Conclusions: This study confirms the feasibility of direct access valve replacement through the transapical procedure for replacement of the pulmonary valve, as well as validity of the new valved stent design concept. The transapical procedure is targeting a broader patient pool, including the very young and the adult patient. The device design might not be restricted to failing conduits only and could allow for implantation in a larger patient population, including those with native right ventricular outflow tract configurations.
- Published
- 2009
- Full Text
- View/download PDF
192. Surgeons produce innovative ideas which are frequently lost in the labyrinth of patents.
- Author
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Vecht JA, Athanasiou T, Ashrafian H, Mayer E, Darzi A, and von Segesser LK
- Subjects
- Humans, Intellectual Property, Licensure economics, Thoracic Surgery economics, United Kingdom, Licensure legislation & jurisprudence, Patents as Topic legislation & jurisprudence, Thoracic Surgery legislation & jurisprudence
- Abstract
Thoracic and cardiovascular surgery are innovative specialties that regularly recruit the latest technological developments into their armoury of devices and equipment. The introduction of new technology is dependant on patents; an important but single component of intellectual property. Patents enable the attribution of rights to concepts, ideas and inventions and this facilitates ownership, subsequent licensing and overall management of innovation and its outcome. It is not just thoracic and cardiovascular surgery, but the healthcare world in general that experiences ongoing technological evolution; so to remain contemporary, it is important that those in positions of responsibility are familiar with the relevant processes. This requires basic medico-legal knowledge and may be entwined with significant financial responsibility. Penetrating clinical, academic and industrial environments, informed awareness of patents also contributes to important leadership skills, encouraging the incorporation of innovation into the professional milieu. We aim to present through this manuscript an overview of these issues in order to promote awareness of patents within thoracic and cardiovascular surgery using a descriptive and practical approach.
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- 2009
- Full Text
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193. Atrial assist device, a new alternative to lifelong anticoagulation?
- Author
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Abdelnour-Berchtold E, Tozzi P, Siniscalchi G, Hayoz D, and von Segesser LK
- Subjects
- Alloys, Animals, Anticoagulants administration & dosage, Atrial Fibrillation complications, Atrial Fibrillation drug therapy, Atrial Fibrillation physiopathology, Atrial Function, Right, Equipment Design, Materials Testing, Sheep, Stroke prevention & control, Thromboembolism prevention & control, Heart-Assist Devices
- Abstract
Objective: Atrial fibrillation is a very common heart arrhythmia, associated with a five-fold increase in the risk of embolic strokes. Treatment strategies encompass palliative drugs or surgical procedures all of which can restore sinus rhythm. Unfortunately, atria often fail to recover their mechanical function and patients therefore require lifelong anticoagulation therapy. A motorless volume displacing device (Atripump) based on artificial muscle technology, positioned on the external surface of atrium could avoid the need of oral anticoagulation and its haemorrhagic complications. An animal study was conducted in order to assess the haemodynamic effects that such a pump could provide., Methods: Atripump is a dome-shape siliconecoated nitinol actuator sewn on the external surface of the atrium. It is driven by a pacemaker-like control unit. Five non-anticoagulated sheep were selected for this experiment. The right atrium was surgically exposed, the device sutured and connected. Haemodynamic parameters and intracardiac ultrasound (ICUS) data were recorded in each animal and under three conditions; baseline; atrial fibrillation (AF); atripump assisted AF (aaAF)., Results: In two animals, after 20 min of AF, small thrombi appeared in the right atrial appendix and were washed out once the pump was turned on. Assistance also enhanced atrial ejection fraction. 31% baseline; 5% during AF; 20% under aaAF. Right atrial systolic surfaces (cm2) were; 5.2 +/- 0.3 baseline; 6.2 +/- 0.1 AF; 5.4 +/- 0.3 aaAF., Conclusion: This compact and reliable pump seems to restore the atrial "kick" and prevents embolic events. It could avoid long-term anticoagulation therapy and open new hopes in the care of end-stage heart failure.
- Published
- 2009
- Full Text
- View/download PDF
194. Rapid prototyping of compliant human aortic roots for assessment of valved stents.
- Author
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Kalejs M and von Segesser LK
- Subjects
- Animals, Aorta surgery, Compliance, Computer Simulation, Humans, Imaging, Three-Dimensional, Materials Testing, Pressure, Prosthesis Design, Reproducibility of Results, Silicones, Stents, Swine, Vascular Surgical Procedures education, Vascular Surgical Procedures instrumentation, Aorta anatomy & histology, Models, Anatomic, Models, Cardiovascular, Replica Techniques
- Abstract
Adequate in-vitro training in valved stents deployment as well as testing of the latter devices requires compliant real-size models of the human aortic root. The casting methods utilized up to now are multi-step, time consuming and complicated. We pursued a goal of building a flexible 3D model in a single-step procedure. We created a precise 3D CAD model of a human aortic root using previously published anatomical and geometrical data and printed it using a novel rapid prototyping system developed by the Fab@Home project. As a material for 3D fabrication we used common house-hold silicone and afterwards dip-coated several models with dispersion silicone one or two times. To assess the production precision we compared the size of the final product with the CAD model. Compliance of the models was measured and compared with native porcine aortic root. Total fabrication time was 3 h and 20 min. Dip-coating one or two times with dispersion silicone if applied took one or two extra days, respectively. The error in dimensions of non-coated aortic root model compared to the CAD design was <3.0% along X, Y-axes and 4.1% along Z-axis. Compliance of a non-coated model as judged by the changes of radius values in the radial direction by 16.39% is significantly different (P<0.001) from native aortic tissue--23.54% at the pressure of 80-100 mmHg. Rapid prototyping of compliant, life-size anatomical models with the Fab@Home 3D printer is feasible--it is very quick compared to previous casting methods.
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- 2009
- Full Text
- View/download PDF
195. Endovascular thoracic aortic aneurysm repair without angiography.
- Author
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Tozzi P, Marty B, Ruchat P, Ferrari E, Siniscalchi G, and von Segesser LK
- Abstract
Objective: : Intravascular ultrasound (IVUS) generates high definition circumferential cross-sectional images and provides real-time readout of vascular dimensions, including visualization of vessel branches. We have used it as an alternative to angiography in the endovascular thoracic aneurysm repair work-up., Methods: : Out of consecutive 203 patients with descending thoracic aortic aneurysm, 89 (43.8%) received endovascular treatment [mean age, 68 ± 8 years; range, 29-82; male, 79 (88.7%); female, 10 (11.3%)] without using angiography during the endovascular procedure. IVUS (6 F, 12.5 MHz probe or 10 F 9 MHz) coupled with fluoroscopy for the placement of radiopaque markers was used for target site identification, landing zone measurement, device positioning, and assessment of endovascular repair., Results: : Hospital mortality was 4/89 (4.5%). Number of devices implanted in each patient was 1.2 (range, 1-3). X-ray exposure time was 12 ± 8 minutes. Median procedure time was 63 ± 20 minutes. Conversion to open surgery was necessary in one patient (1.1%) because of aortic dissection. In nine patients (10.1%) left subclavian artery was covered because of a short neck. Two patients (2.2%) had vascular access lesions and required surgical repair. One patient developed paraplegia (1.1%). Early endoleak was observed in eight patients (8.9%) and 4 (4.5%) required additional procedures (proximal or distal extensions). Late conversion was necessary in one patient (1.1%)., Conclusions: : IVUS provides all information necessary for device selection, target site identification as well as safe and correct deployment of thoracic endoprostheses and makes periprocedural angiography unnecessary, thus avoiding the risk of renal failure because of contrast medium.
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- 2009
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196. Interactive Cardio-Vascular and Thoracic Surgery virtual conferences are now printed monthly: more at www.icvts.org.
- Author
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von Segesser LK
- Subjects
- Access to Information, Humans, Printing, Cardiac Surgical Procedures, Editorial Policies, Internet, Periodicals as Topic, Thoracic Surgical Procedures, Vascular Surgical Procedures
- Published
- 2009
- Full Text
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197. Artificial muscle to wash blood out of fibrillating atrium: an alternative to lifelong anticoagulation.
- Author
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Tozzi P, Hayoz D, Siniscalchi G, Salchli F, and von Segesser LK
- Subjects
- Animals, Anticoagulants therapeutic use, Atrial Fibrillation drug therapy, Hemodynamics, Prosthesis Design, Sheep, Artificial Organs, Atrial Fibrillation surgery, Heart-Assist Devices, Myocardium, Thrombosis prevention & control
- Abstract
The Atripump is a motorless, volume displacement pump based on artificial muscle technology that could reproduce the pump function of normal atrium. It could help prevent blood clots due to blood stagnation and eventually avoid anticoagulation therapy in atrial fibrillation (AF). An animal study has been designed to assess mechanical effects of this pump on fibrillating atrium. The Atripump is a dome shaped silicone coated nitinol actuator. A pacemaker like control unit drives the actuator. In five adult sheep, the right atrium (RA) was exposed and dome sutured onto the epicardium. Atrial fibrillation was induced using rapid epicardial pacing (600 beats/min). Ejection fraction of the RA was obtained with intracardiac ultrasound in baseline, AF and Atripump assisted AF conditions. The dome's contraction rate was 60/min with power supply of 12V, 400 mA for 200 ms and ran for 2 hours in total. Mean temperature on the RA was 39+/-1.5 degrees C. Right atrium ejection fraction was 31% in baseline conditions, 5% and 20% in AF and assisted AF, respectively. In two animals a thrombus appeared in the right appendix and washed out once the pump was turned on. The Atripump washes blood out the RA acting as an anticoagulant device. Possible clinical implications in patients with chronic AF are prevention of embolism of cardiac origin and avoidance of hemorrhagic complication due to chronic anticoagulation.
- Published
- 2009
- Full Text
- View/download PDF
198. Temporary caval stenting improves venous drainage during cardiopulmonary bypass.
- Author
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von Segesser LK, Siniscalchi G, Kang K, Maunz O, Horisberger J, Ferrari E, Delay D, and Tozzi P
- Subjects
- Animals, Blood Flow Velocity, Cattle, Central Venous Pressure, Equipment Design, Gravitation, Prosthesis Design, Regional Blood Flow, Ultrasonography, Interventional, Vena Cava, Inferior diagnostic imaging, Cardiopulmonary Bypass, Catheterization, Central Venous instrumentation, Stents, Vena Cava, Inferior physiopathology
- Abstract
Objectives: Assess the benefit of temporary caval stenting for remote venous drainage during cardiopulmonary bypass (CPB)., Methods: Temporary caval stenting was realized in bovine experiments (65+/-6 kg) by the means of self-expanding (18F for insertion, 36F in situ) venous cannulas (Smartcanula LLC, Lausanne, Switzerland) with various lengths: 43 cm, 53 cm, 63 cm vs. a standard 28F wire armed cannula in trans-jugular fashion. Maximal blood flows were assessed for 20, 25 and 30 mmHg of driving pressure with a motorized table height adjustment system. In addition, the inferior caval diameters (just above its bifurcation) were measured in real time with intra-vascular ultrasound (IVUS)., Results: Venous drainage (flow in l/min) at 20 mmHg, 25 mmHg, and 30 mmHg drainage load was 3.5+/-0.5, 3.7+/-0.7 and 4.0+/-0.6 for the 28F standard vs. 4.1+/-0.7, 4.0+/-1.3 and 3.9+/-1.1 for the 36F smart 43 cm, vs. 5.0+/-0.7, 5.3+/-1.3 and 5.4+/-1.4 for the 36F smart 53 cm, vs. 5.2+/-0.5*, 5.6+/-1.1* and 5.8+/-1.0* for the 36F smart 63 cm. The inferior vena caval diameters at 30 mmHg were 13.5+/-4.8 mm for 28F standard, 11.1+/-3.6 for 36F smart 43 cm, 11.3+/-3.2 for 36F 53 cm, and 17.0+/-0.1* for 36F 63 cm (*P<0.05 for 28F standard vs. 36F smart 63 cm long), Conclusions: The 43 cm self-expanding 36F smartcanula outperforms the 28F standard wire armed cannula at low drainage pressures and without augmentation. Temporary caval stenting with long self-expanding venous cannulas provides even better drainage (+51%).
- Published
- 2008
- Full Text
- View/download PDF
199. Totally implantable robot to treat chronic atrial fibrillation.
- Author
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Tozzi P, Hayoz D, Thévenaz P, Roulet JY, Salchli F, and von Segesser LK
- Subjects
- Equipment Design, Equipment Failure Analysis, Humans, Myocardial Contraction physiology, Atrial Fibrillation rehabilitation, Atrial Fibrillation therapy, Biomimetic Materials, Heart physiology, Heart-Assist Devices, Prostheses and Implants, Robotics instrumentation
- Abstract
Chronic atrial fibrillation affects millions of people worldwide. Its surgical treatment often fails to restore the transport function of the atrium. This study first introduces the concept of an atrial assist device (AAD) to restore the pump function of the atrium. The AAD is developed to be totally implantable in the human body with a transcutaneous energy transfer system to recharge the implanted battery. The ADD consists of a motorless pump based on artificial muscle technology, positioned on the external surface of the atrium to compress it and restore its muscular activity. A bench model reproduces the function of a fibrillating atrium to assess the circulatory support that this pump can provide. Atripump (Nanopowers SA, Switzerland) is a dome-shaped silicone-coated nitinol actuator 5 mm high, sutured on the external surface of the atrium. A pacemaker-like control unit drives the actuator that compresses the atrium, providing the mechanical support to the blood circulation. Electrical characteristics: the system is composed of one actuator that needs a minimal tension of 15 V and has a maximum current of 1.5 A with a 50% duty cycle. The implantable rechargeable battery is made of a cell having the following specifications: nominal tension of a cell: 4.1 V, tension after 90% of discharge: 3.5 V, nominal capacity of a cell: 163 mA h. The bench model consists of an open circuit made of latex bladder 60 mm in diameter filled with water. The bladder is connected to a vertically positioned tube that is filled to different levels, reproducing changes in cardiac preload. The Atripump is placed on the outer surface of the bladder. Pressure, volume and temperature changes were recorded. The contraction rate was 1 Hz with a power supply of 12 V, 400 mA for 200 ms. Preload ranged from 15 to 21 cm H(2)O. Maximal silicone membrane temperature was 55 degrees C and maximal temperature of the liquid environment was 35 degrees C. The pump produced a maximal work of 16 x 10(-3) J. Maximal volume pumped was 492 ml min(-1). This artificial muscle pump is compact, follows the Starling law and reproduces the hemodynamic performances of a normal atrium. It could represent a new tool to restore the atrial kick in persistent atrial fibrillation.
- Published
- 2008
- Full Text
- View/download PDF
200. Routine use of self-expanding venous cannulas for cardiopulmonary bypass: benefits and pitfalls in 100 consecutive cases.
- Author
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von Segesser LK, Ferrari E, Delay D, Maunz O, Horisberger J, and Tozzi P
- Subjects
- Adult, Aged, Cardiac Surgical Procedures instrumentation, Equipment Design, Female, Femoral Vein, Humans, Male, Middle Aged, Prospective Studies, Reoperation, Subclavian Vein, Cardiopulmonary Bypass instrumentation, Catheterization, Central Venous instrumentation, Catheterization, Peripheral instrumentation
- Abstract
Objective: Assess the performance of self-expanding venous cannulas for routine use in open-heart surgery., Methods: Prospective study in 100 unselected consecutive patients undergoing open-heart surgery with either remote or central smart venous cannulation., Results: The study focuses on the 76 consecutive adult patients (mean age 59.2+/-17.3 years; 60 males, 16 females) undergoing surgical procedures with total cardiopulmonary bypass for either valve procedures (42/76 patients=55.3%), ascending aorta and arch repair (20/76 patients=26.3%), coronary artery revascularization (13/76 patients=17.1%) or other procedures (11/76 patients=14.5%) with 14/76 patients (18.4%) undergoing redo surgery and 6/76 patients (7.9%) undergoing small access surgery. The mean pump flow achieved by gravity drainage alone accounted for 5.0+/-0.6l/min (=114% of target) in the entire study population (n=76) as compared to the calculated, theoretical pump flow of 4.4+/-0.5l/min (p<0.0001). For the femoral cannulation sub-group (n=35) pump flow achieved by gravity drainage alone accounted for 4.9+/-0.6l/min (=114% of target) as compared to the calculated theoretical pump flow of 4.3+/-0.4l/min (p<0.0001). The corresponding numbers for trans-subclavian cannulation (n=7) are 5.2+/-0.5l/min (111%) for the pump flow achieved by gravity drainage as compared to the theoretical target flow of 4.7+/-0.4l/min. For the central cannulation sub-group (n=34) mean flow achieved by gravity drainage with a self-expanding venous cannula accounted for 5.1+/-0.7l/min (=116% of target) as compared to the calculated theoretical flow of 4.4+/-0.6l/min (p<0.0001)., Conclusion: Full or more than target flow was achieved in 97% of the patients studied undergoing CPB with self-expanding venous cannulas and gravity drainage. Remote venous cannulation with self-expanding cannulas provides similar flows as central cannulation. Augmentation of venous return is no longer necessary.
- Published
- 2008
- Full Text
- View/download PDF
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