34 results on '"Merk DR"'
Search Results
2. Marfan syndrome aortic smooth muscle cells express high levels of microRNA miR-29b
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Merk, DR, primary, Miller, MO, additional, Chin, JT, additional, Dake, BA, additional, Maegdefessel, L, additional, Kimura, N, additional, Iosef, C, additional, Alvira, CM, additional, Robbins, RC, additional, Mohr, FW, additional, and Fischbein, MP, additional
- Published
- 2012
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3. ITA harvesting – Impact of skeletonizing on deep sternal wound infection? A multivariate logistic regression analysis in 13.463 patients
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Gummert, JF, primary, Barten, MJ, additional, Richter, M, additional, Merk, DR, additional, Doll, N, additional, Rastan, A, additional, Falk, V, additional, Walther, T, additional, and Mohr, FW, additional
- Published
- 2004
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4. Predictors of permanent pacemaker implantation after Medtronic CoreValve bioprosthesis implantation.
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Schroeter T, Linke A, Haensig M, Merk DR, Borger MA, Mohr FW, and Schuler G
- Published
- 2012
5. Additional cusp reconstruction does not compromise valve durability and mid-term survival after the David procedure: results from 449 patients.
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Liebrich M, Charitos E, Stadler C, Roser D, Merk DR, Doll N, Hemmer W, and Voth V
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- Aorta, Aortic Valve surgery, Humans, Male, Middle Aged, Reoperation, Replantation, Retrospective Studies, Treatment Outcome, Aortic Valve Insufficiency surgery
- Abstract
Objectives: The aim of this study was to evaluate whether additional cusp interventions and valve types affect aortic valve-related reoperation and mortality rates after the David procedure., Methods: Between 1997 and 2018, a total of 449 patients {372 males; mean age 54.2 [standard deviation (SD) 15.2] years, range: 12.7-79.9 years} underwent elective valve-sparing aortic root replacement (David procedure) for aortic regurgitation and were prospectively followed up clinically and echocardiographically., Results: The follow-up was 94% complete. Cumulative follow-up time was 2268 patient-years [mean follow-up time 5.1 (4.3 SD) years]. Thirty-day mortality was 2.2% (n = 10). Late (>30 days) survival did not differ from that of the age- and gender-matched general population. Freedom from reoperation in patients without additional cusp reconstruction was 94% [95% confidence interval (CI) 91-98] and 92% (95% CI 88-97) at 5 and 10 years, respectively, which was not significantly different (P = 1) for patients who did require additional cusp reconstruction 98% (95% CI 95-100) and 89% (95% CI 81-99). In patients with tricuspid aortic valves (n = 338), freedom from reoperation was 96% (95% CI 94-99) and 93% (95% CI 88-97) at 5 and 10 years, respectively. Patients with bicuspid aortic valves (n = 111) had a freedom from reoperation of 94% (95% CI 89-99) at 5 years and 88% (95% CI 79-98) at 10 years (P = 0.021 for the comparison to tricuspid aortic valve). Overall, 23 patients (5%; 1%/patient-year) required reoperation with a mean interval of 4.5 (4.8 SD) months., Conclusions: The David procedure revealed low mid-term reoperation risk and excellent survival independent of adjunctive cusp interventions/valve morphology and is comparable with that of the age- and gender-matched general population., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)
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- 2020
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6. Fatal complications associated with surgical left atrial appendage exclusion.
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Wehbe MS, Doll N, and Merk DR
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- Aged, Atrial Appendage physiopathology, Atrial Fibrillation diagnosis, Atrial Fibrillation physiopathology, Echocardiography, Transesophageal, Fatal Outcome, Female, Heart Injuries diagnostic imaging, Heart Injuries physiopathology, Heart Injuries surgery, Hemodynamics, Humans, Male, Pericardial Effusion diagnostic imaging, Pericardial Effusion physiopathology, Pericardial Effusion surgery, Stroke diagnostic imaging, Stroke physiopathology, Tomography, X-Ray Computed, Treatment Outcome, Atrial Appendage surgery, Atrial Fibrillation surgery, Cardiac Surgical Procedures adverse effects, Heart Injuries etiology, Pericardial Effusion etiology, Stroke etiology
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- 2018
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7. Correcting Arrhythmias: Interventional and Surgical Ablation Therapy.
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Doll N, Götte J, Wehbe MS, Weimar T, and Merk DR
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- 2017
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8. Haemodynamic benefits of rapid deployment aortic valve replacement via a minimally invasive approach: 1-year results of a prospective multicentre randomized controlled trial.
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Borger MA, Dohmen PM, Knosalla C, Hammerschmidt R, Merk DR, Richter M, Doenst T, Conradi L, Treede H, Moustafine V, Holzhey DM, Duhay F, and Strauch J
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- Aged, Bioprosthesis, Female, Heart Valve Prosthesis, Hemodynamics, Humans, Male, Prospective Studies, Aortic Valve Stenosis surgery, Heart Valve Prosthesis Implantation instrumentation, Heart Valve Prosthesis Implantation methods, Minimally Invasive Surgical Procedures methods
- Abstract
Objectives: Aortic valve replacement (AVR) via minimally invasive surgery (MIS) may provide clinical benefits in patients with aortic valve disease. A new class of bioprosthetic valves that enable rapid deployment AVR (RDAVR) may facilitate MIS. We here report the 1-year results of a randomized, multicentre trial comparing the outcomes for MIS-RDAVR with those for conventional AVR via full sternotomy (FS) with a commercially available stented aortic bioprosthesis., Methods: A total of 100 patients with aortic stenosis were enrolled in a prospective, multicentre, randomized comparison trial (CADENCE-MIS). Key exclusion criteria included AVR requiring concomitant procedures, ejection fraction of <25% and recent myocardial infarction or stroke. Patients were randomized to undergo MIS-RDAVR via upper hemisternotomy (EDWARDS INTUITY) or AVR via FS with a commercially available stented valve. Procedural, early and late clinical outcomes were assessed for both groups. Haemodynamic performance was evaluated by an echocardiography CoreLaboratory., Results: Technical success was achieved in 94% of MIS-RDAVR patients. MIS-RDAVR was associated with significantly reduced cross-clamp times compared with FS (41.3 ± 20.3 vs 54.0 ± 20.3 min, P < 0.001). Clinical and functional outcomes were similar at 30 days and 1 year postoperatively for both groups. While both groups received a similarly sized implanted valve (22.9 ± 2.1 mm MIS-RDAVR vs 23.0 ± 2.1 mm FS-AVR; P = 0.91), MIS-RDAVR patients had significantly lower peak gradients 1 year postoperatively (16.9 ± 5.3 vs 21.9 ± 8.6 mmHg; P = 0.033) and a trend towards lower mean gradients (9.1 ± 2.9 vs 11.5 ± 4.3 mmHg; P = 0.082). In addition, MIS-RDAVR patients had a significantly larger effective orifice area 1 year postoperatively (1.9 ± 0.5 vs 1.7 ± 0.4 cm
2 ; P = 0.047). Paravalvular leaks, however, were significantly more common in the MIS-RDAVR group (P = 0.027)., Conclusions: MIS-RDAVR is associated with a significantly reduced cross-clamp time and better valvular haemodynamic function than FS-AVR. However, paravalvular leak rates are higher with MIS-RDAVR., (© The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)- Published
- 2016
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9. Multimodality Molecular Imaging of Cardiac Cell Transplantation: Part I. Reporter Gene Design, Characterization, and Optical in Vivo Imaging of Bone Marrow Stromal Cells after Myocardial Infarction.
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Parashurama N, Ahn BC, Ziv K, Ito K, Paulmurugan R, Willmann JK, Chung J, Ikeno F, Swanson JC, Merk DR, Lyons JK, Yerushalmi D, Teramoto T, Kosuge H, Dao CN, Ray P, Patel M, Chang YF, Mahmoudi M, Cohen JE, Goldstone AB, Habte F, Bhaumik S, Yaghoubi S, Robbins RC, Dash R, Yang PC, Brinton TJ, Yock PG, McConnell MV, and Gambhir SS
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- Animals, Female, Luciferases, Firefly metabolism, Luminescent Measurements, Mice, Mice, Nude, Positron-Emission Tomography, Transfection, Genes, Reporter, Mesenchymal Stem Cell Transplantation methods, Molecular Imaging, Multimodal Imaging, Myocardial Infarction diagnostic imaging, Myocardial Infarction therapy
- Abstract
Purpose To use multimodality reporter-gene imaging to assess the serial survival of marrow stromal cells (MSC) after therapy for myocardial infarction (MI) and to determine if the requisite preclinical imaging end point was met prior to a follow-up large-animal MSC imaging study. Materials and Methods Animal studies were approved by the Institutional Administrative Panel on Laboratory Animal Care. Mice (n = 19) that had experienced MI were injected with bone marrow-derived MSC that expressed a multimodality triple fusion (TF) reporter gene. The TF reporter gene (fluc2-egfp-sr39ttk) consisted of a human promoter, ubiquitin, driving firefly luciferase 2 (fluc2), enhanced green fluorescent protein (egfp), and the sr39tk positron emission tomography reporter gene. Serial bioluminescence imaging of MSC-TF and ex vivo luciferase assays were performed. Correlations were analyzed with the Pearson product-moment correlation, and serial imaging results were analyzed with a mixed-effects regression model. Results Analysis of the MSC-TF after cardiac cell therapy showed significantly lower signal on days 8 and 14 than on day 2 (P = .011 and P = .001, respectively). MSC-TF with MI demonstrated significantly higher signal than MSC-TF without MI at days 4, 8, and 14 (P = .016). Ex vivo luciferase activity assay confirmed the presence of MSC-TF on days 8 and 14 after MI. Conclusion Multimodality reporter-gene imaging was successfully used to assess serial MSC survival after therapy for MI, and it was determined that the requisite preclinical imaging end point, 14 days of MSC survival, was met prior to a follow-up large-animal MSC study. (©) RSNA, 2016 Online supplemental material is available for this article.
- Published
- 2016
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10. Multimodality Molecular Imaging of Cardiac Cell Transplantation: Part II. In Vivo Imaging of Bone Marrow Stromal Cells in Swine with PET/CT and MR Imaging.
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Parashurama N, Ahn BC, Ziv K, Ito K, Paulmurugan R, Willmann JK, Chung J, Ikeno F, Swanson JC, Merk DR, Lyons JK, Yerushalmi D, Teramoto T, Kosuge H, Dao CN, Ray P, Patel M, Chang YF, Mahmoudi M, Cohen JE, Goldstone AB, Habte F, Bhaumik S, Yaghoubi S, Robbins RC, Dash R, Yang PC, Brinton TJ, Yock PG, McConnell MV, and Gambhir SS
- Subjects
- Animals, Fluorine Radioisotopes, Guanine analogs & derivatives, Magnetic Resonance Imaging, Positron Emission Tomography Computed Tomography, Radiopharmaceuticals, Swine, Genes, Reporter, Heart diagnostic imaging, Mesenchymal Stem Cell Transplantation, Molecular Imaging methods, Multimodal Imaging methods
- Abstract
Purpose To quantitatively determine the limit of detection of marrow stromal cells (MSC) after cardiac cell therapy (CCT) in swine by using clinical positron emission tomography (PET) reporter gene imaging and magnetic resonance (MR) imaging with cell prelabeling. Materials and Methods Animal studies were approved by the institutional administrative panel on laboratory animal care. Seven swine received 23 intracardiac cell injections that contained control MSC and cell mixtures of MSC expressing a multimodality triple fusion (TF) reporter gene (MSC-TF) and bearing superparamagnetic iron oxide nanoparticles (NP) (MSC-TF-NP) or NP alone. Clinical MR imaging and PET reporter gene molecular imaging were performed after intravenous injection of the radiotracer fluorine 18-radiolabeled 9-[4-fluoro-3-(hydroxyl methyl) butyl] guanine ((18)F-FHBG). Linear regression analysis of both MR imaging and PET data and nonlinear regression analysis of PET data were performed, accounting for multiple injections per animal. Results MR imaging showed a positive correlation between MSC-TF-NP cell number and dephasing (dark) signal (R(2) = 0.72, P = .0001) and a lower detection limit of at least approximately 1.5 × 10(7) cells. PET reporter gene imaging demonstrated a significant positive correlation between MSC-TF and target-to-background ratio with the linear model (R(2) = 0.88, P = .0001, root mean square error = 0.523) and the nonlinear model (R(2) = 0.99, P = .0001, root mean square error = 0.273) and a lower detection limit of 2.5 × 10(8) cells. Conclusion The authors quantitatively determined the limit of detection of MSC after CCT in swine by using clinical PET reporter gene imaging and clinical MR imaging with cell prelabeling. (©) RSNA, 2016 Online supplemental material is available for this article.
- Published
- 2016
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11. Deep sedation versus general anesthesia in percutaneous edge-to-edge mitral valve reconstruction using the MitraClip system.
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de Waha S, Seeburger J, Ender J, Desch S, Eitel I, Reinhardt A, Pöss J, Fuernau G, Noack T, Merk DR, Schuler G, Sievers HH, Mohr FW, and Thiele H
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- Aged, Aged, 80 and over, Cardiac Catheterization adverse effects, Equipment Design, Female, Germany, Humans, Intensive Care Units, Length of Stay, Male, Mitral Valve Insufficiency diagnosis, Prospective Studies, Registries, Risk Factors, Severity of Illness Index, Time Factors, Treatment Outcome, Anesthesia, General adverse effects, Cardiac Catheterization instrumentation, Deep Sedation adverse effects, Mitral Valve Insufficiency therapy
- Abstract
Background: Percutaneous edge-to-edge mitral valve reconstruction (PMVR) has emerged as a treatment option in patients with severe mitral regurgitation not considered suitable candidates for surgery. The majority of PMVR procedures are performed under general anesthesia (GA), although deep sedation (DS) appears to be an attractive alternative. We thus sought to assess the impact on intensive care unit (ICU) length of stay, efficacy, and safety of DS in comparison to GA in patients undergoing PMVR using the MitraClip(®) system., Methods: Sixty consecutive patients underwent PMVR procedures at two centers. The first 30 patients were treated by GA followed by 30 patients undergoing DS under different settings. The primary clinical endpoint was ICU length of stay. The primary efficacy endpoint included procedural success and procedural duration. The safety endpoint was defined as a composite of death, stroke, cardiogenic shock, moderate and severe bleeding as well as pneumonia., Results: The ICU length of stay was significantly shorter in the DS group in comparison to GA patients (p = 0.001). The hospital length of stay did not differ following DS in comparison to GA (p = 0.96). Procedural success was high in both groups (100 versus 96.7 %, p = 0.34) at similar procedural duration time (p = 0.60). No difference between GA and DS was observed with respect to the occurrence of the combined safety endpoint (p = 0.47)., Conclusions: In comparison to GA, DS reduces the ICU length of stay in PMVR without negative effects on safety and efficacy. Prospective randomized trials are needed to confirm these findings.
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- 2016
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12. A simple and accurate method for computer-aided transapical aortic valve replacement.
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Karar ME, Merk DR, Falk V, and Burgert O
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- Aortic Valve Stenosis, Heart Valve Prosthesis, Humans, Aortic Valve, Heart Valve Prosthesis Implantation, Imaging, Three-Dimensional
- Abstract
Background and Purpose: Transapical aortic valve replacement (TAVR) is a recent minimally invasive surgical treatment technique for elderly and high-risk patients with severe aortic stenosis. In this paper, a simple and accurate image-based method is introduced to aid the intra-operative guidance of TAVR procedure under 2-D X-ray fluoroscopy., Methods: The proposed method fuses a 3-D aortic mesh model and anatomical valve landmarks with live 2-D fluoroscopic images. The 3-D aortic mesh model and landmarks are reconstructed from interventional X-ray C-arm CT system, and a target area for valve implantation is automatically estimated using these aortic mesh models. Based on template-based tracking approach, the overlay of visualized 3-D aortic mesh model, landmarks and target area of implantation is updated onto fluoroscopic images by approximating the aortic root motion from a pigtail catheter motion without contrast agent. Also, a rigid intensity-based registration algorithm is used to track continuously the aortic root motion in the presence of contrast agent. Furthermore, a sensorless tracking of the aortic valve prosthesis is provided to guide the physician to perform the appropriate placement of prosthesis into the estimated target area of implantation., Results: Retrospective experiments were carried out on fifteen patient datasets from the clinical routine of the TAVR. The maximum displacement errors were less than 2.0mm for both the dynamic overlay of aortic mesh models and image-based tracking of the prosthesis, and within the clinically accepted ranges. Moreover, high success rates of the proposed method were obtained above 91.0% for all tested patient datasets., Conclusion: The results showed that the proposed method for computer-aided TAVR is potentially a helpful tool for physicians by automatically defining the accurate placement position of the prosthesis during the surgical procedure., (Copyright © 2014 Elsevier Ltd. All rights reserved.)
- Published
- 2016
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13. Porcine xenograft for aortic, mitral and double valve replacement: long-term results of 2544 consecutive patients.
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Lehmann S, Merk DR, Etz CD, Oberbach A, Uhlemann M, Emrich F, Funkat AK, Meyer A, Garbade J, Bakhtiary F, Misfeld M, and Mohr FW
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- Aged, Aged, 80 and over, Female, Heart Valves surgery, Humans, Male, Multivariate Analysis, Retrospective Studies, Stents, Bioprosthesis adverse effects, Bioprosthesis statistics & numerical data, Heart Valve Diseases surgery, Heart Valve Prosthesis adverse effects, Heart Valve Prosthesis statistics & numerical data, Heart Valve Prosthesis Implantation adverse effects, Heart Valve Prosthesis Implantation instrumentation, Heart Valve Prosthesis Implantation statistics & numerical data
- Abstract
Objectives: The aim of this study was to evaluate the results after stented porcine xenograft implantation with Linx™ anticalcification treatment in the aortic and/or mitral position in elderly patients., Methods: Over a decade, a total of 2544 patients receiving aortic (AVR = 1920), mitral (MVR = 347) or double valve (DVR = 277) replacement (between November 2001 and March 2012) were evaluated. The study was designed on an 'all comers' basis including all patients with elective, urgent or emergent need for valve replacement. Outcome was assessed by reviewing the prospectively acquired hospital database as well as regular follow-up information obtained by annual written interviews., Results: Mean patient age was 76.5 ± 6 (AVR), 73.8 ± 7 (MVR) and 74.2 ± 7 (DVR) years, respectively; 54.2%/41.9%/42.0% were male, and active endocarditis was diagnosed in 4.5%/19.9%/22.1%; indication for valve surgery and the logistic EUROSCORE I predicted risk for mortality was 15.4 ± 15%/19.9 ± 19%/22.3 ± 21%, respectively. Concomitant mitral valve repair was required in 196 (10.2%) (AVR) patients; coronary artery bypass graft surgery (CABG) in 840 (43.8%) (AVR), 82 (23.7%) (MVR) and 94 (34.1%) (DVR) patients; cryoablation in 232 (12.1%)/81 (23.4%)/67 (24.3%) patients and surgery on the thoracic aorta in 166 (8.7%)/12 (3.5%)/41 (14.9%) patients, respectively. The mean follow-up was 4.5 ± 3.5 years. The rate of freedom from endocarditis after 10 years was 98.3 ± 0.4%/97.5 ± 1.0%/97.4 ± 1.6% (P = n.s.). The rate of freedom from structural valve disease was 96.3 ± 0.6%/93.8 ± 2.4%/92.8 ± 2.2% (AVR versus DVR, P = 0.009), and from thromboembolic events was 94.8 ± 1.0%/91.5 ± 2.9%/97.9 ± 1.3%. The 30-day survival rate was 97.3 ± 0.4%/95.1 ± .1.2%/92.8 ± 1.6% and the 10-year survival rate was 42.1 ± 1.5%/33.9 ± 4.7%/22.1 ± 7.1%, respectively., Conclusions: The Epic™ stented porcine xenograft is associated with acceptable survival, with large proportions of patients free from valve-related complications and freedom from valve reintervention for all older, in-coming patients., (© The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)
- Published
- 2016
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14. Off-pump transapical neo-chordae implantation.
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Merk DR, Aidietis A, and Seeburger J
- Published
- 2015
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15. Mitral valve repair with neo-chordae.
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Merk DR, Mohr FW, and Seeburger J
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- 2015
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16. Minimally invasive aortic valve replacement: the Leipzig experience.
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Lehmann S, Merk DR, Etz CD, Seeburger J, Schroeter T, Oberbach A, Uhlemann M, Hoellriegel R, Haensig M, Leontyev S, Garbade J, Misfeld M, and Mohr FW
- Abstract
Background: Minimally invasive techniques are progressively challenging traditional approaches in cardiothoracic surgery. Minimally invasive aortic valve replacement (AVR) has become a routine procedure at our institution., Methods: We retrospectively analyzed all patients undergoing minimally invasive isolated AVR between January 2003 and March 2014, at our institution. Mean follow-up was 4.7±4.3 years (range: 0-18 years) and was 99.8% complete., Results: There were 1,714 patients who received an isolated minimally invasive AVR. The mean (± SD) patient age was 65±12.8 years, ejection fraction 60%±12% and log EuroSCORE 5.3%±5.1%. Mean cross-clamp time was 58±18 minutes and mean cardiopulmonary bypass (CPB) time was 82.9±26.7 minutes. Thirty-day survival was 97.8%±0.4%, and 69.4%±1.7% at 10-years. The multivariate analysis revealed age at surgery [P=0.016; odds ratio (OR), 1.1], length of surgery time (P=0.002; OR, 1.01), female gender (P=0.023; OR, 3.54), preoperative myocardial infarction (MI) (P=0.006; OR, 7.87), preoperative stroke (P=0.001; OR, 13.76) and preoperative liver failure (P=0.015; OR, 10.28) as independent risk factors for mortality. Cox-regression analysis revealed the following predictors for long term mortality: age over 75 years (P<0.001; OR, 3.5), preoperative dialysis (P<0.01; OR, 2.14), ejection fraction less than 30% (P=0.003; OR, 3.28) and urgent or emergency operation (P<0.001; OR, 2.3)., Conclusions: Minimally invasive AVR can be performed safely and effectively with very few perioperative complications. The early and long-term outcomes in these patients are acceptable.
- Published
- 2015
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17. Minimal invasive aortic valve replacement surgery is associated with improved survival: a propensity-matched comparison.
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Merk DR, Lehmann S, Holzhey DM, Dohmen P, Candolfi P, Misfeld M, Mohr FW, and Borger MA
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- Aged, Bioprosthesis, Female, Heart Valve Prosthesis, Heart Valve Prosthesis Implantation methods, Humans, Kaplan-Meier Estimate, Male, Propensity Score, Proportional Hazards Models, Retrospective Studies, Aortic Valve surgery, Heart Valve Prosthesis Implantation mortality, Minimally Invasive Surgical Procedures mortality
- Abstract
Objectives: To compare early and long-term outcomes of minimally invasive surgery (MIS) versus full sternotomy (FS) isolated aortic valve replacement (AVR)., Methods: We retrospectively analysed all patients who underwent isolated bioprosthetic AVR between 2003 and March 2012 at our institution. Matching was performed based on a propensity score, which was obtained using the output of a logistic regression on relevant preoperative risk factors. Mean follow-up was 3.1±2.7 years (range 0-9.0 years) and was 99.8% complete., Results: A total of 2051 patients (FS, 1572; MIS, 479) underwent isolated bioprosthetic AVR during the study period. MIS patients were significantly younger (67.8±11.2 vs 70.4±9.4 years) and had a lower logistic EuroSCORE (6.6±6.4 vs 11.2±13.4%, both P<0.001). Propensity matching resulted in 477 matched patients from each group, with no significant differences in any of the preoperative variables. Aortic cross-clamp times were significantly longer in MIS patients (59.4±16.0 vs 56.9±14.6 min, P=0.008). Nonetheless, MIS AVR was associated with a significantly lower incidence of intra-aortic balloon pump usage (0.4 vs 2.1%, P=0.042) and in-hospital mortality (0.4 vs 2.3%, P=0.013), while FS patients had a lower rate of re-exploration for bleeding (1.5 vs 4.2%, P=0.019). Five- and 8-year survival post-AVR was significantly higher in MIS patients (89.3±2.4% and 77.7±4.7% vs 81.8±2.2% and 72.8±3.1%, respectively, P=0.034). Cox regression analysis revealed MIS (hazard ratio: 0.47, 95% confidence interval: 0.26-0.87) as an independent predictor of long-term survival., Conclusion: MIS AVR is associated with very good early and long-term survival, despite longer myocardial ischaemic times. MIS AVR can be performed safely with results that are at least equivalent to those achieved through an FS., (© The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)
- Published
- 2015
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18. A randomized multicenter trial of minimally invasive rapid deployment versus conventional full sternotomy aortic valve replacement.
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Borger MA, Moustafine V, Conradi L, Knosalla C, Richter M, Merk DR, Doenst T, Hammerschmidt R, Treede H, Dohmen P, and Strauch JT
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- Aged, Aged, 80 and over, Bioprosthesis, Female, Humans, Male, Middle Aged, Minimally Invasive Surgical Procedures, Prospective Studies, Stents, Aortic Valve Stenosis surgery, Heart Valve Prosthesis Implantation methods, Sternotomy
- Abstract
Background: Minimally invasive surgical procedures (MIS) may offer several advantages over conventional full sternotomy (FS) aortic valve replacement (AVR). A novel class of aortic valve prostheses has been developed for rapid-deployment AVR (RDAVR). We report a randomized, multicenter trial comparing the outcomes for MIS-RDAVR with those of conventional FS-AVR., Methods: A total of 100 patients with aortic stenosis were enrolled in a prospective, multicenter, randomized comparison trial (CADENCE-MIS). Exclusion criteria included ejection fraction below 25%, AVR requiring concomitant procedures, and recent myocardial infarction or stroke. Patients were randomized to undergo MIS-RDAVR through an upper hemisternotomy (n = 51) or AVR by FS with a conventional stented bioprosthesis (n = 49). Three patients were excluded before the procedure, and 3 more patients who were randomized to undergo RDAVR were excluded because of their anatomy. Procedural, early clinical outcomes, and functional outcomes were assessed for the remaining 94 patients. Hemodynamic performance was assessed by an echocardiography core laboratory., Results: Implanted valve sizes were similar between groups (22.9 ± 2.1 vs 23.0 ± 2.1 mm, p = 0.9). MIS-RDAVR was associated with significantly reduced aortic cross-clamp times compared with FS-AVR (41.3 ± 20.3 vs 54.0 ± 20.3 minutes, p < 0.001), although cardiopulmonary bypass times were similar (68.8 ± 29.0 vs 74.4 ± 28.4 minutes, p = 0.21). Early clinical outcomes were similar between the two groups, including quality of life measures. The RDAVR patients had a significantly lower mean transvalvular gradient (8.5 vs 10.3 mm Hg, p = 0.044) and a lower prevalence of patient-prosthesis mismatch (0% vs 15.0%, p = 0.013) 3 months postoperatively compared with the FS-AVR patients., Conclusions: RDAVR by the MIS approach is associated with significantly reduced myocardial ischemic time and better valvular hemodynamic function than FS-AVR with a conventional stented bioprosthesis. Rapid deployment valves may facilitate the performance of MIS-AVR., (Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)
- Published
- 2015
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19. Enhanced caspase activity contributes to aortic wall remodeling and early aneurysm development in a murine model of Marfan syndrome.
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Emrich FC, Okamura H, Dalal AR, Penov K, Merk DR, Raaz U, Hennigs JK, Chin JT, Miller MO, Pedroza AJ, Craig JK, Koyano TK, Blankenberg FG, Connolly AJ, Mohr FW, Alvira CM, Rabinovitch M, and Fischbein MP
- Subjects
- Animals, Aorta enzymology, Aortic Aneurysm diagnosis, Aortic Aneurysm enzymology, Aortic Aneurysm genetics, Aortic Aneurysm prevention & control, Autoradiography, Caspase Inhibitors pharmacology, Cells, Cultured, Disease Models, Animal, Disease Progression, Elastin metabolism, Female, Fibrillin-1, Fibrillins, Fluorescent Antibody Technique, Male, Marfan Syndrome genetics, Mice, Inbred C57BL, Mice, Mutant Strains, Microfilament Proteins genetics, Microscopy, Electron, Scanning, Muscle, Smooth, Vascular diagnostic imaging, Muscle, Smooth, Vascular drug effects, Muscle, Smooth, Vascular ultrastructure, Mutation, Myocytes, Smooth Muscle drug effects, Myocytes, Smooth Muscle ultrastructure, Time Factors, Tomography, Emission-Computed, Single-Photon, Aortic Aneurysm etiology, Apoptosis drug effects, Caspases metabolism, Cell Membrane enzymology, Marfan Syndrome complications, Muscle, Smooth, Vascular enzymology, Myocytes, Smooth Muscle enzymology, Vascular Remodeling drug effects
- Abstract
Objective: Rupture and dissection of aortic root aneurysms remain the leading causes of death in patients with the Marfan syndrome, a hereditary connective tissue disorder that affects 1 in 5000 individuals worldwide. In the present study, we use a Marfan mouse model (Fbn1(C1039G/+)) to investigate the biological importance of apoptosis during aneurysm development in Marfan syndrome., Approach and Results: Using in vivo single-photon emission computed tomographic-imaging and ex vivo autoradiography for Tc99m-annexin, we discovered increased apoptosis in the Fbn1(C1039G/+) ascending aorta during early aneurysm development peaking at 4 weeks. Immunofluorescence colocalization studies identified smooth muscle cells (SMCs) as the apoptotic cell population. As biological proof of concept that early aortic wall apoptosis plays a role in aneurysm development in Marfan syndrome, Fbn1(C1039G/+) mice were treated daily from 2 to 6 weeks with either (1) a pan-caspase inhibitor, Q-VD-OPh (20 mg/kg), or (2) vehicle control intraperitoneally. Q-VD-OPh treatment led to a significant reduction in aneurysm size and decreased extracellular matrix degradation in the aortic wall compared with control mice. In vitro studies using Fbn1(C1039G/+) ascending SMCs showed that apoptotic SMCs have increased elastolytic potential compared with viable cells, mostly because of caspase activity. Moreover, in vitro (1) cell membrane isolation, (2) immunofluorescence staining, and (3) scanning electron microscopy studies illustrate that caspases are expressed on the exterior cell surface of apoptotic SMCs., Conclusions: Caspase inhibition attenuates aneurysm development in an Fbn1(C1039G/+) Marfan mouse model. Mechanistically, during apoptosis, caspases are expressed on the cell surface of SMCs and likely contribute to elastin degradation and aneurysm development in Marfan syndrome., (© 2014 American Heart Association, Inc.)
- Published
- 2015
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20. Transcatheter mitral valve repair: where are we?
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Merk DR, Emrich FC, Mohr FW, and Seeburger J
- Subjects
- Animals, Heart Valve Prosthesis Implantation methods, Humans, Aortic Valve Stenosis surgery, Cardiac Catheterization, Heart Valve Prosthesis, Mitral Valve surgery, Mitral Valve Insufficiency surgery
- Abstract
Mitral valve regurgitation is the second most common form of valve pathology after aortic stenosis needing surgery. While open surgical repair is still the gold standard, innovative interventional approaches have emerged as an alternative treatment option for high-risk patients. While only a few of these new techniques have been approved for the clinical setting, many others are currently under development or in pre-clinical testing. This editorial will attempt to summarize all current transcatheter-based innovations targeting the mitral valve and explore their potential for the future.
- Published
- 2014
- Full Text
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21. Bilateral versus single lung transplant for idiopathic pulmonary fibrosis.
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Lehmann S, Uhlemann M, Leontyev S, Seeburger J, Garbade J, Merk DR, Bittner HB, and Mohr FW
- Subjects
- Adult, Arterial Pressure, Chi-Square Distribution, Extracorporeal Membrane Oxygenation, Female, Germany, Humans, Idiopathic Pulmonary Fibrosis complications, Idiopathic Pulmonary Fibrosis diagnosis, Idiopathic Pulmonary Fibrosis mortality, Idiopathic Pulmonary Fibrosis physiopathology, Kaplan-Meier Estimate, Lung Transplantation adverse effects, Lung Transplantation mortality, Male, Middle Aged, Multivariate Analysis, Odds Ratio, Proportional Hazards Models, Pulmonary Artery physiopathology, Respiration, Artificial, Respiratory Insufficiency etiology, Respiratory Insufficiency therapy, Retrospective Studies, Risk Factors, Time Factors, Treatment Outcome, Idiopathic Pulmonary Fibrosis surgery, Lung Transplantation methods
- Abstract
Objectives: It is unknown if uni- or bilateral lung transplant is best for treatment of usual idiopathic pulmonary fibrosis. We reviewed our single-center experience comparing both treatments., Materials and Methods: Between 2002 and 2011, one hundred thirty-eight patients at our institution underwent a lung transplant. Of these, 58 patients presented with idiopathic pulmonary fibrosis (56.9%) and were the focus of this study., Results: Thirty-nine patients received a single lung transplant and 19 patients a bilateral sequential lung transplant. The mean patient age was 54 ± 10 years, and 69% were male. The intraoperative course was uneventful, save for 7 patients who needed extracorporeal membrane oxygenation support. Three patients had respiratory failure before the lung transplant that required mechanical ventilation and was supported by extracorporeal membrane oxygenation. Elevated pulmonary artery pressure > 40 mm Hg was identified as an independent predictor of early mortality by uni- and multivariate analysis (P = .01; OR 9.7). Using a Cox regression analysis, postoperative extracorporeal membrane oxyge-nation therapy (P = .01; OR 10.2) and the need for > 10 red blood cell concentrate during the first 72 hours after lung transplant (P = .01; OR 5.6) were independent predictors of long-term survival. Actuarial survival at 1 and 5 years was 65.6% and 55.3%, with no significant between-group differences (70.6% and 54.3%)., Conclusions: Lung transplant is a safe and curative treatment for idiopathic pulmonary fibrosis. According to our results, unilateral lung transplant for idiopathic pulmonary fibrosis is an alternative to bilateral lung transplant and may affect the allocation process.
- Published
- 2014
22. Tirone David procedure for bicuspid aortic valve disease: impact of root geometry and valve type on mid-term outcomes.
- Author
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Kari FA, Kvitting JP, Stephens EH, Liang DH, Merk DR, Fischbein MP, Mitchell RS, and Miller DC
- Subjects
- Adult, Aorta diagnostic imaging, Aorta physiopathology, Aortic Valve physiopathology, Aortic Valve surgery, Aortic Valve Insufficiency etiology, Bicuspid Aortic Valve Disease, Blood Vessel Prosthesis Implantation adverse effects, Cardiac Surgical Procedures adverse effects, Echocardiography, Female, Heart Valve Diseases diagnosis, Heart Valve Diseases physiopathology, Humans, Male, Middle Aged, Predictive Value of Tests, Retrospective Studies, Time Factors, Tomography, X-Ray Computed, Treatment Outcome, Young Adult, Aorta surgery, Aortic Valve abnormalities, Blood Vessel Prosthesis Implantation methods, Cardiac Surgical Procedures methods, Heart Valve Diseases surgery
- Abstract
Objectives: A 180/180° configuration has been reported to increase repair durability after valve-sparing aortic root replacement (V-SARR) for bicuspid aortic valve (BAV) disease. We studied the impact of commissural angular configuration (CAC) and of BAV type on valve performance after V-SARR., Methods: A total of 85 BAV patients (68 males, age 44 ± 11 years) underwent Tirone David-V V-SARR between 1997 and 2013. BAV type was documented intraoperatively, and CAC determined from pre- and postoperative computed tomography scans as the angle subtended by the non-fused cusp. Transthoracic echocardiogram was performed at 6 ± 3 days and at 2.9 ± 2.1 years. Functional end-points included freedom from aortic regurgitation (AR) 1+, AR 2+ and freedom from AR progression (0 to 1+, or 1+ to 2+). Tested variables included preoperative CAC (>160 vs <160°) and changes in CAC after V-SARR (Δ > 30° vs Δ < 30°) and Sievers' BAV type (SØ or S1)., Results: CAC in SØ-BAV (n = 26) changed minimally from 164 ± 12 to 171 ± 11° (mean Δ = 7.2 ± 16°, P = 0.044), whereas in S1-BAV (n = 59) CAC changed substantially from 132 ± 19 to 156 ± 18° (mean Δ = 27 ± 21°, P < 0.001). Larger postoperative CAC angles were not linked to better mid-term valve performance, but Sievers' BAV type had a major effect on valve performance: mild AR in S1/i BAV progressed more often (76 vs 32% at 4 years, P = 0.017) and 1+ AR was more frequent (70 vs 36% at 4 years, P = 0.008) compared with SØ-BAV., Conclusions: BAV type, including number of raphes, sinuses and commissures (SØ superior to S1) but not commissure geometry within the neoroot alone, appears to be linked to functional outcomes after V-SARR for BAV., (© The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)
- Published
- 2014
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23. Mitral valve pathology in severely impaired left ventricles can be successfully managed using a right-sided minimally invasive surgical approach.
- Author
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Garbade J, Seeburger J, Merk DR, Pfannmüller B, Vollroth M, Barten MJ, Borger MA, and Mohr FW
- Subjects
- Aged, Cardiopulmonary Bypass, Female, Heart Failure surgery, Humans, Kaplan-Meier Estimate, Male, Middle Aged, Mitral Valve pathology, Postoperative Complications, Retrospective Studies, Treatment Outcome, Heart Ventricles physiopathology, Minimally Invasive Surgical Procedures methods, Minimally Invasive Surgical Procedures mortality, Mitral Valve surgery, Mitral Valve Annuloplasty methods, Mitral Valve Annuloplasty mortality
- Abstract
Objectives: We sought to review our experience in patients with severely impaired left ventricular function (ejection fraction (EF) ≤ 30%) who underwent minimally invasive mitral valve (MV) surgery (Mini-MV)., Methods: Between 1999 and 2010, a total of 3450 patients underwent Mini-MV surgery at our institution. Of these, 177 had severely impaired left ventricular function (EF < 30%, including ischaemic and non-ischaemic cardiomyopathy). Primary indication for surgery was MV regurgitation in all but 5 patients (2.8%), who were diagnosed with mixed regurgitation and stenosis. Mean age of patients was 67 ± 11 years and 110 were male (62.1%). Mean EuroSCORE predicted risk of mortality was 14.7 ± 13.6%., Results: MV repair was accomplished in 86.4% of patients (n = 153), and MV replacement was performed in 13.6% (n = 24). Primary MV repair included implantation of a rigid annuloplasty ring (mean size 29.5 ± 2.2 mm) in 95.4% of patients, and additional MV procedures as required. Concomitant procedures consisted of tricuspid valve surgery in 15.3% of patients, atrial fibrillation ablation in 27.1% and atrial septal defect/persistent foramen ovale closure in 5.6%. The duration of cardiopulmonary bypass was 123 ± 64 min and aortic cross-clamp time was 67 ± 27 min. Thirty-day mortality was 7.9%. The mean follow-up time was 3 ± 2.5 years, and the follow-up was 94.0% complete. Ten-year survival was 45.5% (95% CI: 35.2-55.9) for the overall group. The rate of MV-related reintervention was 4%, while heart transplantation was performed in 6%., Conclusions: Mini-MV surgery in patients with significantly impaired left ventricular function can be performed with a reasonable operative mortality and acceptable long-term survival for this high-risk patient cohort.
- Published
- 2013
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24. Potential role of γδ T cell-derived IL-17 in acute cardiac allograft rejection.
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Kimura N, Nakae S, Itoh S, Merk DR, Wang X, Gong Y, Okamura H, Chang PA, Adachi H, Robbins RC, and Fischbein MP
- Subjects
- Animals, Mice, Mice, Inbred BALB C, Receptors, Antigen, T-Cell, gamma-delta, Graft Rejection immunology, Heart Transplantation, Interleukin-17 immunology, T-Lymphocytes immunology
- Abstract
Background: Although αβ T cells are known to participate in the development of acute cardiac allograft rejection, the role of γδ T cells remains poorly understood. We hypothesized that γδ T cells contribute to acute allograft rejection thru interleukin (IL)-17 production., Methods: Donor hearts from FVB mice (H-2q) were heterotopically transplanted into C57BL/6-wild type (WT) and γδ T cell-deficient (TCRδ-/-) recipient mice (H-2b). Overall graft survival was monitored. Graft infiltrating cell profile, including γδ T cell subtype, cytokine expression, and myeloperoxidase activity were measured by flow cytometry, TaqMan (Applied Biosystems, Carlsbad, CA) polymerase chain reaction, and myeloperoxidase assay, respectively, on postoperative days 3 and 6., Results: Graft survival was prolonged in TCRδ-/- recipients compared with WT controls. Graft infiltrating cells, including CD45+, CD4+, CD8+, and Gr1+ cells were significantly decreased in TCRδ-/- recipients compared with WT. Donor hearts transplanted into TCRδ-/- recipients had reduced IL-17 and IL-6 messenger RNA expression. Corroborating the gene expression, intracellular cytokine staining showed decreased IL-17 producing cells in TCRδ-/- recipients. Finally, Vγ1+ and Vγ4+ T cells did not produce IL-17, although both represent 20% to 30% total graft infiltrating γδ T cells., Conclusions: The γδ T cells promote acute cardiac allograft rejection, presumably by producing IL-17. The γδ T cell depletion may prove beneficial in prolonging allograft survival by suppressing IL-17 production., (Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)
- Published
- 2012
- Full Text
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25. Video-atlas of transapical aortic valve implantation.
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Holzhey DM, Noack T, Merk DR, Seeburger J, and Borger MA
- Published
- 2012
- Full Text
- View/download PDF
26. MicroRNA-21 blocks abdominal aortic aneurysm development and nicotine-augmented expansion.
- Author
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Maegdefessel L, Azuma J, Toh R, Deng A, Merk DR, Raiesdana A, Leeper NJ, Raaz U, Schoelmerich AM, McConnell MV, Dalman RL, Spin JM, and Tsao PS
- Subjects
- Angiotensin II pharmacology, Animals, Aortic Aneurysm, Abdominal complications, Aortic Aneurysm, Abdominal enzymology, Apoptosis drug effects, Apoptosis genetics, Cell Proliferation drug effects, Gene Expression Profiling, Humans, Inflammation complications, Inflammation genetics, Inflammation pathology, Interleukin-6 pharmacology, Mice, Mice, Inbred C57BL, MicroRNAs genetics, PTEN Phosphohydrolase metabolism, Pancreatic Elastase, Proto-Oncogene Proteins c-akt metabolism, Sus scrofa, Up-Regulation drug effects, Aortic Aneurysm, Abdominal genetics, Aortic Aneurysm, Abdominal pathology, MicroRNAs metabolism, Nicotine pharmacology
- Abstract
Identification and treatment of abdominal aortic aneurysm (AAA) remains among the most prominent challenges in vascular medicine. MicroRNAs are crucial regulators of cardiovascular pathology and represent possible targets for the inhibition of AAA expansion. We identified microRNA-21 (miR-21) as a key modulator of proliferation and apoptosis of vascular wall smooth muscle cells during development of AAA in two established murine models. In both models (AAA induced by porcine pancreatic elastase or infusion of angiotensin II), miR-21 expression increased as AAA developed. Lentiviral overexpression of miR-21 induced cell proliferation and decreased apoptosis in the aortic wall, with protective effects on aneurysm expansion. miR-21 overexpression substantially decreased expression of the phosphatase and tensin homolog (PTEN) protein, leading to increased phosphorylation and activation of AKT, a component of a pro-proliferative and antiapoptotic pathway. Systemic injection of a locked nucleic acid-modified antagomir targeting miR-21 diminished the pro-proliferative impact of down-regulated PTEN, leading to a marked increase in the size of AAA. Similar results were seen in mice with AAA augmented by nicotine and in human aortic tissue samples from patients undergoing surgical repair of AAA (with more pronounced effects observed in smokers). Modulation of miR-21 expression shows potential as a new therapeutic option to limit AAA expansion and vascular disease progression.
- Published
- 2012
- Full Text
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27. Inhibition of microRNA-29b reduces murine abdominal aortic aneurysm development.
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Maegdefessel L, Azuma J, Toh R, Merk DR, Deng A, Chin JT, Raaz U, Schoelmerich AM, Raiesdana A, Leeper NJ, McConnell MV, Dalman RL, Spin JM, and Tsao PS
- Subjects
- Adolescent, Aged, Angiotensin II metabolism, Angiotensin II pharmacology, Animals, Aortic Aneurysm, Abdominal chemically induced, Aortic Aneurysm, Abdominal genetics, Aortic Aneurysm, Abdominal pathology, Apolipoproteins E genetics, Apolipoproteins E metabolism, Collagen genetics, Collagen metabolism, Disease Models, Animal, Disease Progression, Elastin genetics, Elastin metabolism, Gene Expression, Humans, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, MicroRNAs genetics, Middle Aged, Pancreatic Elastase metabolism, Pancreatic Elastase pharmacology, Protein Isoforms genetics, Protein Isoforms metabolism, Swine, Young Adult, Aneurysm, Ruptured prevention & control, Aortic Aneurysm, Abdominal therapy, MicroRNAs antagonists & inhibitors, MicroRNAs metabolism
- Abstract
MicroRNAs (miRs) regulate gene expression at the posttranscriptional level and play crucial roles in vascular integrity. As such, they may have a role in modifying abdominal aortic aneurysm (AAA) expansion, the pathophysiological mechanisms of which remain incompletely explored. Here, we investigate the role of miRs in 2 murine models of experimental AAA: the porcine pancreatic elastase (PPE) infusion model in C57BL/6 mice and the AngII infusion model in Apoe-/- mice. AAA development was accompanied by decreased aortic expression of miR-29b, along with increased expression of known miR-29b targets, Col1a1, Col3a1, Col5a1, and Eln, in both models. In vivo administration of locked nucleic acid anti-miR-29b greatly increased collagen expression, leading to an early fibrotic response in the abdominal aortic wall and resulting in a significant reduction in AAA progression over time in both models. In contrast, overexpression of miR-29b using a lentiviral vector led to augmented AAA expansion and significant increase of aortic rupture rate. Cell culture studies identified aortic fibroblasts as the likely vascular cell type mediating the profibrotic effects of miR-29b modulation. A similar pattern of reduced miR-29b expression and increased target gene expression was observed in human AAA tissue samples compared with that in organ donor controls. These data suggest that therapeutic manipulation of miR-29b and its target genes holds promise for limiting AAA disease progression and protecting from rupture.
- Published
- 2012
- Full Text
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28. miR-29b participates in early aneurysm development in Marfan syndrome.
- Author
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Merk DR, Chin JT, Dake BA, Maegdefessel L, Miller MO, Kimura N, Tsao PS, Iosef C, Berry GJ, Mohr FW, Spin JM, Alvira CM, Robbins RC, and Fischbein MP
- Subjects
- Age Factors, Angiotensin II Type 1 Receptor Blockers pharmacology, Animals, Aorta pathology, Aortic Aneurysm genetics, Aortic Aneurysm pathology, Aortic Aneurysm prevention & control, Apoptosis, Apoptosis Regulatory Proteins metabolism, Cells, Cultured, Disease Models, Animal, Elastin genetics, Elastin metabolism, Female, Fibrillin-1, Fibrillins, Genetic Therapy methods, Losartan pharmacology, Male, Marfan Syndrome complications, Marfan Syndrome genetics, Marfan Syndrome pathology, Marfan Syndrome therapy, Matrix Metalloproteinase 2 metabolism, Mice, Mice, Inbred C57BL, Mice, Transgenic, MicroRNAs genetics, Microfilament Proteins genetics, Microfilament Proteins metabolism, NF-kappa B metabolism, Oligonucleotides, Antisense administration & dosage, Real-Time Polymerase Chain Reaction, Reverse Transcriptase Polymerase Chain Reaction, Transforming Growth Factor beta metabolism, Up-Regulation, Aorta metabolism, Aortic Aneurysm metabolism, Marfan Syndrome metabolism, MicroRNAs metabolism
- Abstract
Rationale: Marfan syndrome (MFS) is a systemic connective tissue disorder notable for the development of aortic root aneurysms and the subsequent life-threatening complications of aortic dissection and rupture. Underlying fibrillin-1 gene mutations cause increased transforming growth factor-β (TGF-β) signaling. Although TGF-β blockade prevents aneurysms in MFS mouse models, the mechanisms through which excessive TGF-β causes aneurysms remain ill-defined., Objective: We investigated the role of microRNA-29b (miR-29b) in aneurysm formation in MFS., Methods and Results: Using quantitative polymerase chain reaction, we discovered that miR-29b, a microRNA regulating apoptosis and extracellular matrix synthesis/deposition genes, is increased in the ascending aorta of Marfan (Fbn1(C1039G/+)) mice. Increased apoptosis, assessed by increased cleaved caspase-3 and caspase-9, enhanced caspase-3 activity, and decreased levels of the antiapoptotic proteins, Mcl-1 and Bcl-2, were found in the Fbn1(C1039G/+) aorta. Histological evidence of decreased and fragmented elastin was observed exclusively in the Fbn1(C1039G/+) ascending aorta in association with repressed elastin mRNA and increased matrix metalloproteinase-2 expression and activity, both targets of miR-29b. Evidence of decreased activation of nuclear factor κB, a repressor of miR-29b, and a factor suppressed by TGF-β, was also observed in Fbn1(C1039G/+) aorta. Furthermore, administration of a nuclear factor κB inhibitor increased miR-29b levels, whereas TGF-β blockade or losartan effectively decreased miR-29b levels in Fbn1(C1039G/+) mice. Finally, miR-29b blockade by locked nucleic acid antisense oligonucleotides prevented early aneurysm development, aortic wall apoptosis, and extracellular matrix deficiencies., Conclusions: We identify increased miR-29b expression as key to the pathogenesis of early aneurysm development in MFS by regulating aortic wall apoptosis and extracellular matrix abnormalities.
- Published
- 2012
- Full Text
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29. Interleukin-16 deficiency suppresses the development of chronic rejection in murine cardiac transplantation model.
- Author
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Kimura N, Itoh S, Nakae S, Axtell RC, Velotta JB, Bos EJ, Merk DR, Gong Y, Okamura H, Nagamine CM, Adachi H, Kornfeld H, Robbins RC, and Fischbein MP
- Subjects
- Animals, Antibodies pharmacology, Antibodies therapeutic use, Cell Proliferation drug effects, Chemokines metabolism, Coronary Artery Disease complications, Cytokines metabolism, Disease Models, Animal, Graft Rejection etiology, Interleukin-16 genetics, Interleukin-16 immunology, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Transplantation, Homologous, Tunica Intima cytology, Tunica Intima drug effects, Coronary Artery Disease physiopathology, Coronary Artery Disease prevention & control, Graft Rejection physiopathology, Graft Rejection prevention & control, Heart Transplantation physiology, Interleukin-16 deficiency
- Abstract
Background: IL-16 promotes the recruitment of various cells expressing CD4, a receptor for IL-16. The precise role of IL-16 in transplant rejection remains unknown; therefore, the present study investigated the contribution of IL-16 to the development of chronic rejection in heart transplants., Methods: C-H-2(bm12)KhEg (H-2(bm12)) donor hearts were transplanted into (1) IL-16-deficient (IL-16(-/-)) C57BL/6J or (b) wild type (WT) control recipients (MHC class II mismatch). Grafts were harvested at 52 days, parenchymal rejection was assessed by the ISHLT grading system, and CAV was examined morphometrically. Graft infiltrating cells were detected 10 and 52 days after transplantation. Intragraft cytokine and chemokine profiles were assessed. To confirm the role of IL-16 in CAV development, C-H-2(bm12)KhEg (H-2(bm12)) donor hearts were transplanted into C57BL/6J WT recipients treated with (1) anti-IL-16-neutralization monoclonal antibody or (b) control immunoglobulin G. Grafts were harvested at 52 days, and CAV was quantified morphometrically. Graft-infiltrating cells were examined histologically., Results: Parenchymal rejection and CAV was significantly attenuated in donor hearts transplanted into IL-16(-/-) recipient mice compared with WT controls. Donor hearts transplanted into IL-16(-/-) recipients had a significant reduction in coronary artery luminal occlusion, intima-to-media ratio, and percentage of diseased vessels. CAV was associated with decreased donor organ inflammation, as well as donor organ cytokine (IL-1β and IL-6) and chemokine (MCP-1 and KC) protein expression. Intimal proliferation and inflammatory cell infiltration were significantly reduced in hearts transplanted into recipients treated with an IL-16-neutralization antibody., Conclusions: IL-16-deficiency reduced graft inflammatory cell recruitment, and allograft inflammatory cytokine and chemokine production. Therefore, IL-16 neutralization may provide a potential target for novel therapeutic treatment for cardiac allograft rejection., (Copyright © 2011 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)
- Published
- 2011
- Full Text
- View/download PDF
30. Aortic valve prosthesis tracking for transapical aortic valve implantation.
- Author
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Karar ME, Merk DR, Chalopin C, Walther T, Falk V, and Burgert O
- Subjects
- Aged, 80 and over, Aortic Valve Stenosis diagnosis, Cardiac Catheterization methods, Female, Fluoroscopy methods, Heart Valve Prosthesis Implantation instrumentation, Humans, Male, Minimally Invasive Surgical Procedures methods, Monitoring, Intraoperative methods, Sampling Studies, Sensitivity and Specificity, Aortic Valve Stenosis surgery, Heart Valve Prosthesis, Heart Valve Prosthesis Implantation methods, Image Processing, Computer-Assisted, Magnetic Resonance Imaging, Interventional methods
- Abstract
Purpose: Transapical aortic valve implantation (TA-AVI) is a new minimally invasive surgical treatment of aortic stenosis for high-risk patients. The placement of aortic valve prosthesis (AVP) is performed under 2D X-ray fluoroscopic guidance. Difficult clinical complications can arise if the implanted valve is misplaced. Therefore, we present a method to track the AVP in 2D X-ray fluoroscopic images in order to improve the accuracy of the TA-AVI., Methods: The proposed tracking method includes the template matching approach to estimate the position of AVP and a shape model of the prosthesis to extract the corner points of the AVP in each image of sequence. To start the AVP tracking procedure, an initialization step is performed by manually defining the corner points of the prosthesis in the first image of sequence to provide the required algorithm parameters such as the AVP model parameters., Results: We evaluated the AVP tracking method on six 2D intra-operative fluoroscopic image sequences. The results of automatic AVP localization agree well with manually defined AVP positions. The maximum localization errors of tracked prosthesis are less than 1 mm and within the clinical accepted range., Conclusions: For assisting the TA-AVI, a method for tracking the AVP in 2D X-ray fluoroscopic image sequences has been developed. Our AVP tracking method is a first step toward automatic optimal placement of the AVP during the TA-AVI.
- Published
- 2011
- Full Text
- View/download PDF
31. Image-guided transapical aortic valve implantation: sensorless tracking of stenotic valve landmarks in live fluoroscopic images.
- Author
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Merk DR, Karar ME, Chalopin C, Holzhey D, Falk V, Mohr FW, and Burgert O
- Abstract
Objective: Aortic valve stenosis is one of the most frequently acquired valvular heart diseases, accounting for almost 70% of valvular cardiac surgery. Transapical transcatheter aortic valve implantation has recently become a suitable minimally invasive technique for high-risk and elderly patients with severe aortic stenosis. In this article, we aim to automatically define a target area of valve implantation, namely, the area between the coronary ostia and the lowest points of two aortic valve cusps. Therefore, we present a new image-based tracking method of these aortic landmarks to assist in the placement of aortic valve prosthesis under live 2D fluoroscopy guidance., Methods: We propose a rigid intensity-based image registration technique for tracking valve landmarks in 2D fluoroscopic image sequences, based on a real-time alignment of a contrast image including the initialized manual valve landmarks to each image of sequence. The contrast image is automatically detected to visualize aortic valve features when the aortic root is filled with a contrast agent., Results: Our registration-based tracking method has been retrospectively applied to 10 fluoroscopic image sequences from routine transapical aortic valve implantation procedures. Most of all tested fluoroscopic images showed a successful tracking of valve landmarks, especially for the images without contrast agent injections., Conclusions: A new intraoperative image-based method has been developed for tracking aortic valve landmarks in live 2D fluoroscopic images to assist transapical aortic valve implantations and to increase the overall safety of surgery as well.
- Published
- 2011
- Full Text
- View/download PDF
32. The coronary sinus: a versatile option for pacemaker implantation during minimally invasive valve surgery.
- Author
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Seeburger J, Merk DR, Holzhey D, Borger MA, Doll N, and Mohr FW
- Subjects
- Aged, Female, Heart Valve Prosthesis Implantation, Humans, Minimally Invasive Surgical Procedures, Tricuspid Valve surgery, Tricuspid Valve Insufficiency surgery, Cardiac Pacing, Artificial methods, Coronary Sinus, Pacemaker, Artificial
- Abstract
A 66-year-old patient with previous mitral valve replacement underwent redo surgery for severe secondary tricuspid valve regurgitation. The patient presented with right heart failure and was pacemaker-dependent prior to surgery. Tricuspid valve replacement and implantation of a cardiac pacemaker lead through the coronary sinus were performed. The operative procedure and current literature are discussed.
- Published
- 2009
- Full Text
- View/download PDF
33. Late perforation of a right ventricular pacing lead: a potentially dangerous complication.
- Author
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Schroeter T, Doll N, Borger MA, Groesdonk HV, Merk DR, and Mohr FW
- Subjects
- Bradycardia physiopathology, Cardiac Surgical Procedures, Heart Injuries diagnostic imaging, Heart Injuries surgery, Heart Ventricles diagnostic imaging, Heart Ventricles surgery, Hemothorax etiology, Humans, Male, Middle Aged, Pericardium injuries, Pleura injuries, Shock, Hemorrhagic etiology, Suture Techniques, Thoracotomy, Tomography, X-Ray Computed, Treatment Outcome, Bradycardia therapy, Cardiac Pacing, Artificial adverse effects, Heart Injuries etiology, Heart Ventricles injuries, Pacemaker, Artificial adverse effects
- Abstract
Four days after uncomplicated implantation of a two-chamber pacemaker and a normal postoperative course, a patient was referred to our hospital with left-sided hemothorax and early hemorrhagic shock. Chest X-ray and CT scan were suspicious of a right ventricular lead perforation with additional pericardial and pleural injury. Immediate surgery was performed via a lateral thoracotomy and the perforation was repaired via direct suture. An epimyocardial ventricular lead was implanted simultaneously. The patient made an uneventful recovery.
- Published
- 2009
- Full Text
- View/download PDF
34. Massive cerebral air embolism after bronchoscopy and central line manipulation.
- Author
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Seeburger J, Borger MA, Merk DR, Doll S, Bittner HB, and Mohr FW
- Subjects
- Emphysema surgery, Female, Humans, Lung Transplantation, Middle Aged, Severity of Illness Index, Bronchoscopy adverse effects, Catheterization, Central Venous adverse effects, Cerebral Infarction etiology, Embolism, Air etiology
- Abstract
A 50-year-old woman who underwent double-lung transplantation suffered a massive cerebral air embolism with severe neurological impairment and temporary hemodynamic deterioration after surveillance bronchoscopy and central line removal. We hypothesize that this was due to microscopic pulmonary parenchymal injury during bronchoscopy as well as air entrainment during removal of the central venous line, with subsequent transpulmonary passage into the cerebral vessels.
- Published
- 2009
- Full Text
- View/download PDF
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