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Significant progress in understanding and overcoming cardiac xenograft rejection using a clinically relevant large animal pig-to-baboon model has accelerated in recent years. This advancement is based on improved immune suppression, which attained more effective regulation of B lymphocytes and possibly newer donor genetics. These improvements have enhanced heterotopic cardiac xenograft survival from a few weeks to over 2 years, achieved intrathoracic heterotopic cardiac xenograft survival of 50 days and orthotopic survival of 57 days. This encouraging progress has rekindled interest in xenotransplantation research and refocused efforts on preclinical orthotopic cardiac xenotransplantation. [ABSTRACT FROM AUTHOR]

Background: Tissue engineering of autologous heart valves with the potential to grow and to remodel represents a promising concept. Here we describe the use of cryopreserved umbilical cord blood-derived CD133+ cells as a single cell source for the tissue engineering of heart valves. Methods: After expansion and differentiation of CD133+ cells, phenotypes were analyzed by immunohistochemistry and cryopreserved. Heart valve scaffolds fabricated from a biodegradable polymer (n = 8) were seeded with blood-derived myofibroblasts and subsequently coated with blood-derived endothelial cells. Afterward, the heart valve constructs were grown in a pulse duplicator system. Analysis of all heart valves, including histology, immunohistochemistry, electron microscopy, fluorescence imaging, and biochemical and biomechanical examination, was performed. Results: The tissue-engineered heart valves showed endothelialized layered tissue formation including connective tissue between the inside and the outside of the scaffold. The notion of an intact endothelial phenotype was substantiated by fluorescence imaging studies of cellular nitric oxide production and Ca2+ signaling. Electron microscopy showed that the cells had grown into the pores and formed a confluent tissue layer. Biochemical examination showed extracellular matrix formation (77% ± 9% collagen of human pulmonary leaflet tissue [HPLT], 85% ± 61% glycosaminoglycans of HPLT and 67% ± 17% elastin of HPLT). Conclusions: Importantly, this study demonstrates in vitro generation of viable human heart valves based on CD133+ cells derived from umbilical cord blood. These findings constitute a significant step forward in the development of new clinical strategies for the treatment of congenital defects. [Copyright &y& Elsevier]

Objective: Heart–lung transplantation for patients with pulmonary atresia and ventricular septal defect is challenging. The aim of the study was to present a single-center experience with heart–lung transplantation in this difficult group of patients. Methods: A retrospective review identified 9 patients aged 4.1 to 45.6 years (median, 25.4 years) with pulmonary atresia and ventricular septal defect who underwent heart–lung transplantation. Four (44.4%) patients had previous heart operations: 3 of them had palliative procedures (systemic-to-pulmonary shunts), and 1 had multistage correction. A standard transplantation method was used, with the exception of 1 patient with heterotaxy syndrome who underwent a modified operation. Major aortopulmonary collateral arteries were controlled by using various techniques. Results: Follow-up ranged between 2 days and 12.6 years (median, 1.2 years). The hospital mortality rate was 22.2% (n = 2). In the late postoperative period, 3 patients died. The survival curve was similar to that of patients with other diagnoses undergoing heart–lung transplantation. The median length of intensive care unit stay was 58 days (range, 22–82 days), and the median length of hospital stay was 83 days (range, 35–136 days). The most common early complication was bleeding requiring re-exploration. In all cases the bleeding was proved to be from collateral vessels. Conclusions: Heart–lung transplantation in patients with pulmonary atresia and ventricular septal defect requires carefully planned and meticulously performed surgical intervention. This management should be taken into consideration as a future option if the specific anatomy is uncorrectable in early childhood, and the palliative procedures should be avoided. [Copyright &y& Elsevier]

Purpose: The objective of this study was to show the use of 3-dimensional printing models to fabricate a custom-made occluder for device embolization of an anastomotic leak after replacement of the ascending aorta and the aortic arch in a human immunodeficiency virus (HIV)-infected patient. Description: We present a 50-year-old HIV-infected patient who underwent ascending aorta and aortic arch replacement for a type A dissection, and who had an aortic arch pseudoaneurysm (sized 5 × 5 × 4 cm) with a slit-shaped entrance hole located anteriorly to the implanted supra-aortic vessels. The patient''s 128-slice computed tomography data were visualized and reconstructed. Afterward we fabricated a life-like replica of the complex pathology of the ascending aorta and the aortic arch using a rapid prototyping machine. After careful examination of the model, we fabricated a custom-made occluder device for interventional closure of the leakage. Evaluation: Using data derived from 128-slid computed tomography linked to proprietary software, we were able to create models of the ascending aorta, the aortic arch end, especially the pseudoaneurysm with its slit-shaped opening between the aortic lumen and the aneurysm. This was very helpful to build a perfectly fitting custom-made occluder device to plan and simulate the interventional closure. Moreover, the models were helpful for intra-interventional orientation. Conclusions: The stereolithographic replicas were extremely useful for choosing the treatment option and for planning and simulating the occlusion of the pseudoaneurysm. Furthermore, the models were necessary for our engineers who were building the custom-made occluder device. [Copyright &y& Elsevier]

Objective: Microwave ablation has been reported as efficient for the surgical treatment of long-standing atrial fibrillation. However, the influence of ablation lesions on long-term results is not known. Methods: From August of 2000 to November of 2003, 41 patients underwent a left atrial endocardial microwave ablation procedure after a Cox-Maze–like lesion set for long-standing atrial fibrillation concomitant to surgery for valvular or coronary artery disease. Mitral valve surgery alone or combined was performed in 31 cases (75.6%). The mean diameter of the left atrium was 7.19 ± 1.44 cm. The mean duration of preoperative atrial fibrillation was 4.7 ± 3.6 years. Patient follow-up was conducted by means of direct clinical examination, electrocardiography, and transthoracic echocardiography. The mean follow-up was 5.37 ± 0.91 years. Results: Patient follow-up was achieved in 82% of cases (n = 28). Seven patients (17%) died during follow-up. Stroke was the cause of death in 1 patient with persistence of atrial fibrillation. Major complications occurred in 4 (14.3%) of the patients that were related to the persistence of atrial fibrillation. At 5 years follow-up, 39.3% of patients (11/28) were in sinus rhythm. Seventeen patients (60.7%) were in New York Heart Association classes I and II, and 11 patients (39.3%) were in New York Heart Association class III at the time of follow-up. Conclusion: In our experience, left atrial endocardial microwave ablation for long-standing atrial fibrillation after a Cox-Maze–like ablation lesion set during surgery for organic heart disease is not a reliable method of achieving long-term conversion to sinus rhythm. [Copyright &y& Elsevier]

Purpose: Resternotomy for aortic valve replacement in patients with previous coronary artery bypass grafting and an internal mammary artery graft may be a surgical problem. Thus, we are exploring the effect of using rapid prototyping techniques for surgical planning and intraoperative orientation during aortic valve replacement after previous coronary artery bypass grafting (CABG). Description: As a proof of concept, we studied a patient who had undergone CABG 5 years earlier. At that time the patient received a left internal mammary artery graft to the left anterior descending artery and a venous graft to the right coronary artery. Now the patient required aortic valve replacement due to symptomatic aortic valve stenosis. The left internal mammary artery bypass and the right coronary artery bypass were patent and showed good flow in the angiography. The patient was examined by 128-slice computed tomography. The image data were visualized and reconstructed. Afterwards, a replica showing the anatomic structures was fabricated using a rapid prototyping machine. Evaluation: Using data derived from 128-slice computed tomography angiography linked to proprietary software, we were able to create three-dimensional reconstructions of the vascular anatomy after the previous CABG. The models were sterilized and taken to the operating theatre for orientation during the surgical procedure. Conclusions: Stereolithographic replicas are helpful for choosing treatment strategies in surgical planning and for intraoperative orientation during reoperations of patients with previous CABG. [Copyright &y& Elsevier]

Purpose: Currently we are exploring the impact of using rapid prototyping techniques for surgical planning and intraoperative orientation during the correction of complex congenital malformation. Description: We studied a patient with a left abnormal subclavian artery and right descending aorta as a rare cause of dyspnea and dysphagia. The patient was examined by magnetic resonance imaging angiography. The image data were visualized and reconstructed. Afterward a replica of the malformation was fabricated using a rapid prototyping machine. In addition, a stereolithographic model of an intracardiac lesion (ventricular septal defect) was fabricated with data obtained from a computed tomographic scan. Evaluation: Using data derived from a magnetic resonance imaging angiography or computed tomographic scan linked to proprietary software, we were able to create three-dimensional reconstructions of complex vascular pathology and intracardiac lesions. In addition, we fabricated replicas of congenital malformations using a rapid prototyping machine. The models could be sterilized and taken to the operating room for orientation during the corrective surgical procedure. Conclusions: Stereolithographic replicas are helpful for choosing treatment strategies, surgical planning of corrections, and intraoperative orientation, and as demonstrations on life-like models for the patient. [Copyright &y& Elsevier]

Background: The magnetic vascular positioner (MVP), a device for distal bypass anastomosis in coronary surgery, was developed to allow a simple and rapid procedure and to improve graft patency. We analyze our mid-term results with this device. Methods: Eighteen distal anastomoses were performed by using the MVP, and 18 with a hand-sewn technique were completed in 11 patients. The target arteries for the MVP anastomosis were the left anterior descending in 9 patients, a marginal branch in 4, a diagonal branch in 3, and right coronary artery in 2. The left internal thoracic artery was used as graft in 9 patients, saphenous vein in 6, right internal thoracic artery in 2, and radial artery in 1. Results: Coronary angiography was performed at discharge and after a complete follow-up of 19 ± 3.5 months. Patency at follow-up was 83.3% (15/18) for MVP anastomoses and 100% (18/18) for hand-sewn anastomoses. All occluded MVP anastomoses were performed with small-size devices. In one patient, a high-grade left main stenosis was overestimated. Competitive flow may be suspected in this case as a cause of graft occlusion. No deaths occurred during hospital stay or during follow-up. Freedom from reintervention was 100%. Conclusions: The MVP is the only mechanical connector for distal anastomoses applicable for all kind of grafts, for all coronary artery locations, and with both end-to-side and side-to-side technique. Mid-term patency of MVP anastomoses is acceptable but inferior to the patency of hand-sewn anastomoses. Occlusion of MVP supplied grafts may be produced by small device size. [Copyright &y& Elsevier]

Background: Tissue engineering of autologous heart valves with the potential to grow and to remodel represents a promising concept in pediatric cardiovascular surgery. Currently we are exploring the impact of cryopreserved human umbilical cord cells (CHUCCs) for the fabrication of tissue-engineered heart valves for patients diagnosed prenatally with congenital heart lesions, potentially enabling heart valve replacement in the early years of life. Methods: Human umbilical cord cells were isolated from vascular segments of umbilical cords and cryopreserved in a cell bank. After 12 weeks the cryopreserved cells were again expanded in culture and characterized by histology, immunohistochemistry, and proliferation assays. Trileaflet heart valve scaffolds were fabricated from a porous polymer (P4HB, Tepha Inc, Cambridge, MA) and sequentially seeded with CHUCCs (n = 10). Five of the heart valve constructs were grown for 7 days in a pulse duplicator and, as a control, five constructs were grown under static cell culture conditions for 7 days. Analysis of all tissue-engineered heart valves included histology, immunohistochemistry, electron microscopy, functional analysis, and biomechanical and biochemical examination. Results: We found that CHUCCs remained viable after 12 weeks of cryopreservation and showed a myofibroblast-like morphology that stained positive for α-actin and fibroblast specific marker. Histology of the tissue-engineered heart valves showed layered tissue formation, including connective tissue between the inside and the outside of the porous scaffold. Immunohistochemistry was positive for collagen (types I, III, and IV), desmin, laminin, and α-actin. Electron microscopy showed that the cells had grown into the pores and formed a confluent tissue layer during maturation in the pulsatile flow system. Biochemical examination showed an increase of extracellular matrix formation in constructs after pulsatile flow exposure compared with the static control group. Functional analysis demonstrated a physiological increase of the intracellular Ca2+ concentration of the recultivated cells and the conditioned constructs after stimulation with histamine. Conclusions: This study demonstrates in vitro generation of viable and functional human heart valves based on CHUCCs and biomimetic flow culture systems. The CHUCCs demonstrated excellent growth potential and abilities of in vitro tissue formation. These findings suggest the potential benefit of establishing autologous human cell banks for pediatric patients diagnosed intrauterinely with congenital defects that will potentially require heart valve replacement in the early years of life. [Copyright &y& Elsevier]

Objective: Neurodevelopmental impairments after repair of congenital heart disease with cardiopulmonary bypass and deep hypothermic circulatory arrest continue to affect the lives of children. To date, the preclinical investigation of cerebral injury mechanisms related to deep hypothermic circulatory arrest has been restricted to expensive, personnel-demanding, and cumbersome large-animal models without validated neuropsychologic assessment. We aimed to establish a rodent recovery model of deep hypothermic circulatory arrest to overcome these disadvantages. Methods: Male rats (n = 34) were cannulated for cardiopulmonary bypass, cooled to a rectal temperature of 16°C to 18°C within 30 minutes, and assigned to deep hypothermic circulatory arrest durations of 0, 45, 60, 75, 90 (n = 6, respectively), or 105 (n = 4) minutes. After rewarming within 40 minutes, animals were weaned from cardiopulmonary bypass at 35.5°C. Neurologic and cognitive performance was assessed with the modified hole board test until postoperative day 14. Thereafter, brains were perfusion fixed and histologically analyzed. Results: Logistic regression analyses identified dose-dependent associations between survival, neurologic or cognitive function, and duration of deep hypothermic circulatory arrest. Functional and histologic deficits were detectable after clinically relevant deep hypothermic circulatory arrest durations. The overall neurologic function did not correlate with histologic outcome (r = 0.51, P > .05). Conclusions: The current study presents a novel recovery model of cardiopulmonary bypass with deep hypothermic circulatory arrest in the rat. In contrast to studies in large animals, even clinically relevant deep hypothermic circulatory arrest durations up to 60 minutes resulted in detectable deficits. Consequently, this experimental model appears to be suitable to further elucidate the mechanisms associated with adverse cerebral outcome after cardiac surgery and deep hypothermic circulatory arrest and to investigate potential neuroprotective strategies. [Copyright &y& Elsevier]

Purpose: The purpose of our study was to evalute the stability of an artificially seeded endothelial cell layer on porcine aortic prostheses under in vivo conditions in the arterial system. Description: Ten female sheep were divided into two groups. Animals of the study group (n = 7) had dissection of their right external jugular vein for cell harvesting. Myofibroblasts and endothelial cells were labelled with PKH-26, seeded onto pretreated (10% citric acid) porcine glutaraldehyde-fixed aortic valves (Freestyle, Medtronic Inc, Duesseldorf, Germany), and the valves were implanted into the descending aorta. Controls (n = 3) received pretreated but unseeded valves. A shunt between the aortic arch and the left atrial appendage ensured systolic or diastolic leaflet motions, or both, that were documented by sonography. After 3 months the valves were explanted. Specimens for scanning electron microscopy and immunohistochemical staining were taken prior to implantation and after explantation. Evaluation: A neointimal proliferation was detected in the control group. No endothelial cells were found on the leaflets and the sinuses, but erythrocytes and thrombocytes were seen entrapped within the collagen fibers. Thrombus formation was documented macroscopically and histologically on the leaflets and the sinuses. In the study group a confluent endothelial cell layer was documented on the walls and leaflets. Neither neointimal proliferation nor any clots were seen. Some cells were still labelled positively indicating their origin from the initial cell seeding. No dilatation of any prosthesis was observed, but all valves showed slight thickening of the leaflets. Conclusions: The artificially seeded endothelial cell layers remained stable under in vivo conditions in the arterial system. Biocompatibility of the prostheses seemed to be improved by reduction of thrombogenicity. [Copyright &y& Elsevier]

Purpose: Inflammation and coagulation disturbances are common consequences of cardiopulmonary bypass (CPB). Recently, miniaturized closed CPB circuits without cardiotomy suction and venous reservoir have been proposed to reduce complication rates. We compared outcomes with conventional (CCPB) and miniaturized cardiopulmonary bypass (MCPB) after coronary artery bypass operations (CABG) with respect to inflammation and coagulation. Description: Thirty patients (23% female; aged 67.9 ± 9.0 years) were prospectively randomly assigned to undergo isolated CABG with CCPB or MCPB. Conventional CPB had a pump prime of 1, 600 mL. Miniaturized CPB consisted of a centrifugal pump, arterial filter, heparinized tubing, and oxygenator with a priming volume of 800 mL. Shed blood was removed by a cell-saving device and reinfused. Measurements included interleukin (IL)-2 receptor, IL-6, IL-10, tumor necrosis factor receptor 55 and 75, C reactive protein, leukocyte differentiation, d-dimers, fibrinogen, and thrombocytes at six time points. Evaluation: In both groups no major complication occurred. However, two dangerous air leaks occurred in the closed MCPB circuit, demonstrating the narrow safety margins. Operative handling was also more difficult owing to limitations in venting and fluid management. International normalized ratio (p = 0.03) and antithrombin III (p = 0.04) levels were elevated during CPB in the CCPB group, most likely owing to differences of the intraoperative anticoagulation management. Repeated measures analysis revealed that not a single parameter of inflammation or clinical outcome showed significant differences among groups. Conclusions: Use of a MCPB affected inflammation and coagulation variables only marginally and did not lead to clinical relevant changes as assessed by blood loss, need for blood products, and intensive care unit and clinical stays. However, safety margins for volume loss, air emboli, and weaning from CPB decrease, because of the closed MCPB circuit. [Copyright &y& Elsevier]

Purpose: Complete covering of an artificial valvular scaffold with endothelial cells may prevent thromboembolic complications and lead to an excellent biocompatibility. For this purpose, we developed a seeding device for reproducible cell seeding on valve containing aortic roots. Description: Human endothelial cells and fibroblasts were obtained from saphenous vein pieces. Cryopreserved aortic roots (n = 25) were put into an especially developed tube, set on a rotator, and incubated with the cell suspension. The device rotated in two axes (sagittal and axial), ensuring slight movements of the leaflets. The rotation alternated with resting periods, allowing cell attachment to the surface. Different resting periods were tested (groups 1, 2, and 3 were 30, 45, and 60 min, respectively; n = 5 each). Total incubation time was 24 hours followed by further culturing for 6 days. In two further groups (groups 4 and 5; n = 5 each), a modified inlay was used to allow the cell suspension to flow around the entire graft. In group 4 the grafts were again incubated with human endothelial cells; however, in group 5 pre-seeding with autologous fibroblasts was done in addition. Immunohistochemical staining with antibodies against factor VIII, CD31, laminin, collagen IV, and CD90 were done, and scanning electron microscopy was done after initial seeding and after 6 days in culture. Evaluation: Seeding resulted in homogenous cell layers on the luminal surface of the free walls in all groups. With resting periods of 45 minutes, these results were also obtained on the leaflets, whereas the other resting times resulted in defects of the endothelial cell layer on the cusps. After 6 days under culture conditions, the endothelial cell layers were confluent and viable, with the exception of the leaflets in group 1. With the modified inlay (groups 4 and 5), confluent cell layers were also achieved on the outer surface. In group 5 pre-seeding with autologous fibroblasts resulted in enhanced synthesis of extracellular matrix proteins, as was demonstrated with immunohistochemical staining for collagen IV and laminin. Conclusions: With this newly developed seeding device, confluent cell layers on valve containing aortic roots were reproducibly achieved. The technique enables further experimental research and even clinical application. [Copyright &y& Elsevier]

Purpose: The main goals in the development of an anastomotic device are to reduce the invasiveness of the procedure and to improve graft patency. We analyze our preliminary clinical experience with the Ventrica magnetic vascular positioner (MVP) series 6000 system. Description: Eighteen distal anastomoses were performed in 11 patients using the MVP. Evaluation: The target artery for MVP was left anterior descending in 9 patients, a marginal branch in 4, the first diagonal branch in 3, and the right coronary artery in 2. Graft material was the left internal thoracic artery in 9 patients, saphenous vein in 6, the right internal thoracic artery in 2, and the radial artery in 1 case. Fifteen anastomoses were performed in an end-to-side and 3 in a side-to-side fashion. Predischarge angiography was performed in 10 of 11 patients. There was a patent MVP anastomosis in all patients. Conclusions: Distal anastomoses using the MVP were performed successfully in all patients. The procedure is simple. Short-term patency is excellent. Further randomized trials are necessary to determine long-term safety and patency. [Copyright &y& Elsevier]

Purpose: The HEARTSTRING is a device designed to enable the creation of a clampless hand-sewn proximal anastomosis. Description: Seventy-six patients who underwent myocardial revascularization had 113 proximal anastomoses created by the HEARTSTRING. Fifty-five procedures were performed on cardiopulmonary bypass and 21, off pump. Evaluation: Of 114 intended proximal anastomoses, 113 (99.1%) were successfully performed using the HEARTSTRING. The conduits anastomosed proximal with support of the HEARTSTRING were in 92 cases saphenous veins and in 21 cases radial arteries. Mean time to perform a HEARTSTRING-supported anastomosis was 6.6 ± 1.2 minutes. One patient (1.3%) died postoperatively; the death was not device related. In 1 additional patient (1.3%), a stroke most likely due to air embolism occurred. Forty-nine patients (64.5%) underwent a predischarge coronary angiography (n = 20) or a contrast multislice computed tomography (n = 29). Of 76 grafts with a HEARTSTRING-supported proximal anastomosis, 74 (97.4%) were patent in these 49 patients. Conclusions: Our initial clinical experience with the HEARTSTRING demonstrates safety, reliability, and ease of use. Side clamping of the ascending aorta can be avoided, potentially decreasing the incidence of neurologic complications. [Copyright &y& Elsevier]

Background: Stent-based left ventricle-to-coronary artery stent (VSTENT) is a newly developed, alternative surgical revascularization procedure (VCAB). We present here our initial experience using this technique. Methods: Twelve patients (10 male and 2 female, mean age 61 ± 13 years) underwent a VCAB concomitant to coronary artery bypass surgery. Myocardial revascularization was performed on-pump with arrested heart in 4 patients, on-pump with beating heart in 6 patients, and off-pump in 2 patients. Average number of coronary anastomoses per patient was 2.4 ± 0.8. In all cases left internal thoracic artery-to-left anterior descending was used. In each patient only one VSTENT was implanted. Target artery for the VCAB was a diagonal branch in 5 patients, an intermediate branch in one patient and a marginal branch in 6 patients. Mean time for the VCAB was 23 ± 5 minutes (17 to 30 minutes). Results: An immediate procedural success was observed in 11 of 12 cases. In one case VCAB was not successful and conventional aortocoronary bypass was performed. One patient died on the second postoperative day due to a systemic inflammatory response syndrome. Autopsy demonstrated a patent VSTENT. Angiography was performed in 10 patients 2 to16 days (9 ± 5 days) postoperatively showing a patent VSTENT in 8 patients. Conclusions: The VCAB was feasible and potentially safe in the short-term postoperative follow-up, particularly with increasing experience after the first patients. Though the VSTENT is a promising tool for myocardial revascularization, long-term safety, patency, and performance of the device needs to be determined. [Copyright &y& Elsevier]

Background: In order to assess different surgical techniques for video-assisted minimally invasive mitral valve surgery, a retrospective study was undertaken comparing the Port-Access system (Cardiovations, Ethicon Inc, Somerville, NJ) and the transthoracic clamp technique. Methods: In 120 patients mitral valve surgery was performed through a small right minithoracotomy using either the Port-Access endovascular cardiopulmonary bypass system (Port-Access, n = 60) or the transthoracic clamp technique (MICRO, n = 60). Mean patient age was 61.5 ± 10.5 years (81 patients with isolated mitral valve insufficiency, 39 patients with combined mitral valve disease). Results: Eighty-one (67.5%) patients underwent mitral valve repair and 39 (32.5%) patients had valve replacement. Mean time of surgery was 4.5 ± 3.5 and 4.1 ± 3.2 hours (p = 0.07), aortic cross-clamp time 89 ± 69 and 78 ± 65 minutes (p = 0.08), mean intensive care unit stay 1.5 ± 2.1 and 1.6 ± 2.5 days (p = ns), and hospital stay 9.0 ± 10.5 and 9.2 ± 9.7 days (p = ns) in the Port-Access and MICRO groups, respectively. In the Port-Access group, there were 6 reexplorations for bleeding, one perforation of the right ventricle with the endopulmonary vent, and 2 reconstructions of the femoral artery necessary after femoral cannulation, compared to one reexploration for bleeding in the MICRO group. There was only one minor paravalvular leak after replacement and 2 cases of residual greater than or equal to grade II mitral valve regurgitation after mitral valve repair in the Port-Access group, necessitating reoperation. In both groups, there was no mortality, no cerebrovascular accident, no aortic dissection, and no conversion to sternotomy. Conclusions: Minimally invasive mitral valve surgery has become a standard approach for isolated mitral valve operations at our institution. The MICRO technique tends to shorten the time of surgery and aortic cross-clamping and reduces perioperative costs by simplifying the operative procedure. [Copyright &y& Elsevier]

Background: Pediatric heart transplantation is a surgical therapy for dilated cardiomyopathy and for complex congenital heart defects with low pulmonary artery resistance. However, it is still discussed as controversial because of uncertain long-term results. We report our experience with pediatric heart transplantation in a heterogeneous population.Methods: Since 1988, 50 heart transplants were performed in 47 patients (30 with dilated cardiomyopathy, 17 with congenital heart disease). Mean age was 9.4 ± 6.9 years (range, 4 days to 17.9 years). Twenty-three patients had a total of 36 previous operations. Clinical outcome was evaluated retrospectively.Results: Perioperative mortality was 6% due to primary graft failure. Late mortality (12%) was caused by acute rejection (n = 2), pneumonia (n = 2), intracranial hemorrhage (n = 1), and suicide (n = 1). Mean follow-up was 5.24 ± 3.6 years. Actuarial 1, 5, and 10 year survival was 86%, 86%, and 80% and improved significantly after 1995 (92% [1 year]; 92% [5 years]). There was no significant difference between patients with dilated or congenital heart disease (1 year: 86% vs 82%; 5 years: 83% vs 74%; 10 years 83% vs 74%; p = 0.62). Three patients with therapy resistant acute or chronic rejection and assisted circulation underwent retransplantation and are alive. Freedom from acute rejection after 5 years was 40% with primary cyclosporine immunosuppression regime and 56% with tacrolimus. Since the introduction of mycophenolate mofetil, freedom from acute rejection increased to 62%. All survivors are at home and in good cardiac condition.Conclusions: Pediatric heart transplantation is the treatment of choice for end-stage dilated cardiomyopathy as for congenital heart disease with excellent clinical midterm results. It is a valid alternative to reconstructive surgery in borderline patients. However, further follow-up is necessary to evaluate the long-term side effects of immunosuppressants. [Copyright &y& Elsevier]

Background: Since introduction in 1999, pulmonary valve replacement in pediatric patients with the Contegra conduit (Medtronic Inc, Minneapolis, MN) has gained widespread application with increasing enthusiasm. However, unexpected graft related adverse effects may occur.Methods: Between April 2001 and December 2002, 29 patients (20 male; mean age, 3.39 ± 3.66 years; range, 0.01 to 13.0 years; mean weight, 11.62 ± 8.73 kg) underwent right ventricular outflow tract reconstruction with the Contegra conduit. Seventeen patients underwent primary repair, 8 had prior homografts, and 4 had other previous operations.Results: There were no deaths. Three early graft related complications were observed. In two infants (age, 1.8 and 3.5 months; weight, 3.6 and 3.8 kg, respectively) thrombus formation at the conduit valve was detected 2 weeks postoperatively. Under anticoagulation with low-molecular-weight heparin, thrombi resolved completely in both patients. One patient (4.5 months, 4.43 kg) developed severe regurgitation due to a fibrous layer covering the inner conduit wall and required conduit exchange 3 weeks postoperatively. After a mean follow-up time of 10.2 ± 6.4 months all patients are in good clinical condition. However, one patient with systemic right ventricular pressure developed pseudoaneurysm at both graft insertion sites and is scheduled for reoperation. Two other patients underwent balloon dilation. Freedom from reoperation and intervention at 1 year is 89.4%. With regard to regurgitation and conduit stenosis all other conduits perform well.Conclusions: Contegra conduits are an alternative to homografts for right ventricular outflow tract reconstruction. However, there is a risk of thrombus formation in small infants so that prophylactic anticoagulation may be necessary. Patients with systemic right ventricular pressure require close observation as pseudoaneurysm formation has been observed. [Copyright &y& Elsevier]

: BackgroundSudden cardiac death remains the most common cause of death after repair of tetralogy of Fallot. It has been suggested that sudden cardiac death is related to right ventricular hypertrophy or dilation. However, it is uncertain whether the preoperative patient status or operative techniques predispose for sudden cardiac death.: MethodsFrom 1958 to 1977, 658 patients underwent repair of tetralogy of Fallot at our institution at a median age of 12.2 ± 8.6 years. One third had at least one previous palliative operation 4.6 ± 2.5 years earlier. A total of 490 patients survived the first postoperative year and were analyzed for sudden cardiac death. During a follow-up period of 25.3 ± 5.8 years (range, 1.0 to 35.5 years), 42 patients died, and 15 (36%) of those deaths were as a result of sudden cardiac death.: ResultsActuarial 10-year, 20-year, and 30-year survival rates were 97%, 94%, and 89%. Freedom from sudden cardiac death was 99%, 98%, and 95% after 10, 20, and 30 years. The risk of sudden cardiac death increased after 10 years from 0.06%/y to 0.20%/y. Univariate predictors (p < 0.1) of sudden cardiac death were use of an outflow tract patch (p = 0.068), male sex (p = 0.048), no previous palliation (p = 0.013), and higher preoperative New York Heart Association status (p = 0.014). Multivariate analysis confirmed these risk factors except use of an outflow tract patch.: ConclusionsThe most important risk factors for sudden cardiac death were higher preoperative New York Heart Association class and no previous palliation. Thus, early surgical intervention is recommended. The risk of sudden cardiac death increases with time, suggesting that long-term follow-up by specialized cardiologists or pediatricians should be intensified. However, all patients who died suddenly had at least two risk factors at the time of surgery. [Copyright &y& Elsevier]

: BackgroundSelective coronary angiography (SCA) is the standard invasive procedure for diagnosis in patients eligible for coronary artery bypass grafting (CABG). A recently developed, highly sensitive multidetector computed tomography (MDCT) scan holds promise to be of almost comparable quality and predictiveness. We examined a blinded series of preoperative patients who were admitted to hospital for conventional and minimally invasive CABG procedures. Patients underwent CT scans in addition to SCA; findings were compared regarding location and degree of coronary artery stenosis.: MethodsTwenty patients underwent electrocardiogram-gated helical CT scanning. Images with 250 ms effective exposure time were reconstructed with retrospective electrocardiogram gating. Location and degree of coronary stenoses were described and compared with findings of SCA. The study was limited to patients with a heart rate of less than 70 beats per minute and who had the ability to hold their breath for 20 to 30 seconds.: ResultsCoronary arteries were clearly displayed by MDCT. Compared with SCA, sensitivity was 92%, specificity 84%, and negative predicted value 89% for significant stenosis (more than 50%). Early forms of atherosclerotic changes were even clearer on MDCT. In addition, the CT examination allowed differentiation of calcified and fatty or fibrous stenoses.: ConclusionsMultidetector CT scanning is an effective noninvasive technique for the diagnosis of coronary artery disease. In selected patients, MDCT scanning might be able to replace SCA as a preoperative test for CABG procedures. The intrathoracic situs can be clearly exposed as it is important for the planning of minimally invasive CABG procedures. [Copyright &y& Elsevier]

Background. This study was designed to evaluate the efficacy of two different stabilizer concepts for off-pump coronary artery bypass grafting.Methods. Between 2000 and 2001, 100 consecutive patients who underwent off-pump coronary artery bypass grafting were randomly assigned to two stabilization systems: the Medtronic Octopus 3 (n = 50) and the Genzyme Immobilizer (n = 50). During operation, two-dimensional cardiac surface motion was assessed by intravital microscopy using orthogonal polarization spectral imaging in 20 vessels at the anterior wall. Postoperative angiography of 47 vessels revealed anastomotic quality.Results. Patient demographics were similar in both groups regarding age, sex, ejection fraction, and New York Heart Association functional class. In 7 patients the randomized Immobilizer was rejected by the surgeon for lateral or posterior wall revascularization and subsequently switched to the Octopus device. Patients received 1.8 ± 0.7 grafts in the Octopus and 1.6 ± 0.5 in the Immobilizer group (p = not significant). Two-dimensional cardiac surface motion was significantly less using the Immobilizer (109.7 ± 32.4 μm versus 423.5 ± 129.6 μm; p < 0.001). Time required for anastomosis was significantly shorter in the Immobilizer group (11.3 ± 3.5 versus 14.9 ± 2.4 minutes; p < 0.001). Postoperative angiography showed no vessel occlusions but two anastomotic stenoses in each group.Conclusions. Both stabilizers have been shown useful for off-pump coronary artery bypass grafting. The Immobilizer system showed better epicardial immobilization of the anterior wall resulting in shorter anastomosis times. However, because the Octopus 3 handling is more flexible and allows easier access to all vessels, it is the device of choice for posterior wall revascularization in our institution. [Copyright &y& Elsevier]