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A Haverich

Publications and source records attributed to A Haverich.

At least 37 records · Page 2Linked to original sources
PubMed2004

Cryopreserved arterial allografts for in situ reconstruction of infected arterial vessels.

OBJECTIVE: To review our experience of using cryopreserved allografts for in situ reconstruction in the presence of infection involving the aorta, iliac or femoral arteries. DESIGN: Retrospective clinical study. METHODS: From 3/2000 to 8/2003 all patients with mycotic aneurysms or secondary infection following earlier prosthetic replacement were treated with cryopreserved human allografts. Forty-two patients, 39 (93%) with a prosthetic graft infection and 3 (7%) with a mycotic aneurysm of the abdominal aorta were treated. Six (14%) had aorto-enteric fistulas, 5 (12%) had ruptured aneurysms, and 2 also had vertebral destruction. The median follow-up time was 20 months (range 1-42 months). RESULTS: Thirty-day mortality was 14%. Three patients died due to multi-organ failure, two patients died from hypovolaemic shock due to allograft rupture and one from rupture of the native aorta. The overall mortality was 24% (four additional patients). Graft patency was 100% at 30 days and 97% at follow up in the survivors. The mean actuarial survival time was 32 months (95% CI=27-37 months). CONCLUSIONS: Cryopreserved allografts for the in situ reconstruction of infected arteries or grafts have acceptable intermediate results.

Aged↗
PubMed2004

Use of a fibrin preparation in the engineering of a vascular graft model.

OBJECTIVE: Morphological and functional characterization of cocultured endothelial cells (EC) and myofibroblasts (MFB) seeded on a matrix composed of a fibrin preparation mimicking the microenvironment of a vascular wall. METHODS: MFB and EC were isolated from human saphenous veins and expanded separately in vitro. MFB were seeded on a composite matrix consisting of a fibrin preparation (with or without transforming growth factor-beta2) and a polyglactin-mesh to form a 3-dimensional structure, which was consecutively reseeded with EC. Seeded matrices were incubated in a bioreactor. Characterization was done including fluorescence staining, live-/dead-assay and immunohistochemistry. RESULTS: High density cocultures in hierarchical structure mimicking the formation of a vascular wall were obtained with nearly complete coverage of the surface with EC. Distribution of preseeded MFB in a 519+/-27 microm thick layer (day 14) was achieved. Cell viability was shown in fluorescence staining for at least 19 days. In deeper layers, no viable cells could be detected within the fibrin preparation. EC covered the surface, had uniform morphology, and their preserved viability was shown for at least 5 days. No EC-ingrowth was found into the fibrin preparation. Neoformation of the matrix proteins laminin and collagen IV was observed. CONCLUSION: A structured coculture of MFB and EC was obtained mimicking the formation of a vascular wall with preserved viability utilizing a fibrin preparation. Nutrition problems seem to limit the maximal extent of MFB in the matrix.

Blood Vessels↗
PubMed2004

Experience with cyclosporine: from revolution to evolution of immunosuppressive protocols in thoracic organ transplantation.

The introduction of cyclosporine into clinical practice of thoracic organ transplantation had a dramatic and positive effect on both short- and long-term survival. Today, the majority of patients are still treated with this drug, and different immunosuppressive combination therapies have further resulted in improved long-term survival. Such combinations to calcineurin inhibitors include prednisolone, mycophenolate mofetil, azathioprine, and Rapamycin. Based on data from our own institution 1- and 5-year survival rates of 86% and 78% can be obtained after heart transplantation and 76% and 59% after lung transplantation. Causes of death are described. Future immunosuppressive strategies will have to concentrate further on the omission of organ-damaging side effects. Also, not a single compound or combination for immunosuppression after thoracic organ transplantation has proved to be effective in cases with chronic rejection (eg, transplant vasculopathy in heart transplantation and bronchiolitis obliterans in lung transplantation). Moreover, with current survival data in mind, quality of life has to be considered a major focus for future designs of immunosuppressive protocols.

Cyclosporine↗
PubMed2004

[Quality of life and exercise capacity in lung transplant recipients].

BACKGROUND: Quality of life in lung transplant recipients (LTR) is reported to be comparable with that of the general population. However, previous studies have shown that exercise capacity was reduced to 30 - 40 % of normal values. The purpose of this study was to investigate the gap between good self-reported quality of life and reduced exercise capacity in LTR, to describe possible correlations and to compare the results with those of a control group (CG). METHODS: 27 LTR 208 +/- 67 days after bilateral lund transplantation (16 male, 11 female; age: 46 +/- 10 years; body mass index: 24 +/- 3 kg x m (- 2), FEV (1) % 75 +/- 27 %) and 30 controls (17 male 13 female; age 47 +/- 15 years; BMI: 26 +/- 4 kg x m (- 2), FEV (1) % 103 +/- 15 %) performed cardiopulmonary exercise testing and were interviewed with the standardized German "Quality of life profile for chronic disease" self-rating questionnaire. RESULTS: Significant differences were shown in objective exercise related variables (peak oxygen consumption: LTR 15.1 +/- 1.8, CG 34.5 +/- 9.1 ml x min (- 1) x kg (- 1); p < 0,01); peak workload: LTR 1.0 +/- 0.2; CG 2.4 +/- 1.0 W. kg (- 1); p < 0.01); percentage of predicted workload: LTR 44 +/- 12, CG 115 +/- 33 %; p < 0.01). The rating of subjective quality of life in physical, psychological and social domains of LTR did not differ from values of the CG or of the general population (n = 1143). The quality of life in the physical domain correlated significantly with peak exercise capacity (LTR r = 0.44, p < 0.05; CG r = 0.37; p < 0.05). CONCLUSION: Patients 7 months after lung transplantation described their physical, social and psychological quality of life as equally good as the healthy control group. However, peak exercise capacity and oxygen consumption were markedly reduced. To improve physical capacity in the range of daily activities, an exercise training program should be offered to patients after lung transplantation.

Adult↗
PubMed2004

Immunosuppressive therapy after human lung transplantation.

In 2002, equal numbers of lung transplantation (LTx) were performed with or without induction therapy with antilymphocyte antibodies, monoclonal anti-CD3 antibody or anti-interleukin-2-receptor monoclonal antibodies. It remains to be established if induction therapy after LTx is beneficial or deleterious for long-term graft and patient survival. The vast majority of lung transplant recipients receive a triple-drug maintenance regimen including a calcineurin inhibitor, a cell-cycle inhibitor and steroids. Equal proportions receive cyclosporin A (CsA) and tacrolimus (Tac). There is also a trend to prescribe mycophenolate mofetil (MMF) instead of azathioprine (Aza). Steroid withdrawal is uncommon even 5 yrs after transplantation. The superiority of Tac over CsA as a maintenance agent has not been established to date, and the administration of MMF instead of Aza in combination with CsA and steroids did not improve graft or patient survival in a recent international, prospective, randomised, controlled trial. Shift from cyclosporin A to tacrolimus has emerged as the first treatment step of refractory acute rejection followed by high-dose steroids or antilymphocyte agents, total lymphoid irradiation or photopheresis. The treatment of chronic rejection remains deceptive and includes varied strategies such as modification of the maintenance regimen, addition of inhaled immunosuppressants and/or total lymphoid irradiation and photopheresis.

Cyclosporine↗
PubMed2003

Impact of preoperative aortic root diameter on long-term aortic valve function after valve sparing aortic root reimplantation.

BACKGROUND: Valve sparing aortic root reimplantation technique in patients with aortic root aneurysm have shown excellent mid-term results. In conjunction with the diameter of the aortic root the mechanical leaflet stress increase, which might have an impact on long-term aortic valve function after valve sparing aortic root reimplantation. METHODS AND RESULTS: From July 1993 to October 2001, 168 patients with aortic root aneurysm underwent valve sparing aortic root reimplantation. Patients with type A aortic dissection were excluded. Thus, 123 patients were analyzed. We identified 47 patients with an preoperative aortic root diameter exceeding 60 mm (group A), 58 patients with an diameter between 50 and 60 mm (group B), and 18 patients with a diameter less than 50 mm (group C). The groups were compared regarding mortality, long-term survival, freedom from reoperation, freedom from severe and moderate aortic valve insufficiency (AI), and postoperative morbidity. Mean follow-up (group A 43+/-26 months, group B 40+/-25 months, group C 23+/-19 months; group C versus group A, P=0.005; group C versus group B, P=0.011) was shorter in group C. Perioperative mortality (group A 2.2%, group B 1.9%, group C 5.2%; P=ns) was comparable between the groups with each one patient. The 3-year survival for group A was 98+/-2%, for group B 96+/-3%, and for group C 100+/-0% (P=ns). Freedom from reoperation for group A was 98+/-2%, for group B 96+/-3%, and for group C 88+/-8% (P=ns). Four patients developed severe or moderate AI, thus freedom from severe and moderate AI for group A was 100+/-0%, for group B 88+/-8%, and for group C 94+/-5% (P=ns). During follow-up no thromboembolic or bleeding events were noticed. CONCLUSIONS: Our data show that the preoperative diameter of the aortic root has no impact on the longevity of the repair. Thus, the reimplantation technique can be recommended for all patients presenting with an aortic root aneurysm and normal leaflets regardless of the aortic root diameter.

Adult↗
PubMed2003

Mortality rates after heart transplantation: how to compare center-specific outcome data?

BACKGROUND: Studies of outcome in cardiac transplantation have focused primarily on identifying patient- and donor-related factors associated with patient mortality. Less consideration has been given to the impact of the transplant center. This study was undertaken to assess variability in heart transplantation outcome in Eurotransplant centers to provide a framework for auditing. METHODS AND RESULTS: In a 2-year period, 1,401 adult patients underwent heart transplantation in 45 centers. The 1-year patient survival rate was 76% (95% CI, 74%-78%) with a range of 0% to 100% at the center level. The risk-adjusted center effect on mortality was estimated by calculating a standardized difference between the observed number of deaths 1 year after transplantation and the expected number of deaths based on the case mix. By assessing within- and between-center variations with empirical Bayes (EB) methods, after adjustment for all registered prognostic factors, an improved estimate of the true center effect was obtained. Compared with the standard risk-adjusted center effect method, fewer outlying centers were identified with the EB method. CONCLUSION: EB methods, because they are known to incorporate more information from the data, enable a more precise and realistic portrayal of heart transplant centers' performances, compared with other risk-adjusted center effect methods. In the context of auditing procedures, EB methods should preferably be used for the identification of centers that deviate significantly from quality standards.

Adolescent↗
PubMed2003

[Ross procedure with combined replacement of the ascending aorta: impact on autograft root function and distensibility].

BACKGROUND: The safety and effectiveness of combined aortic root autograft replacement in combination with ascending aorta replacement has been demonstrated recently. Replacement of the ascending aorta with a vascular prosthesis results in an increase in aortic root distension, and aortic root wall stress. In this study we aimed to assess the autograft root dimensions, distensibility, and autograft valve function in patients after Ross operation combined with replacement of the ascending aorta compared to patients who underwent Ross operation only. PATIENTS AND METHODS: Echocardiographic follow-up was performed on 28 patients after Ross operation with complete root replacement only (group R) and 12 patients who received an additional replacement of the ascending aorta (group R/A). The mean follow-up time was 24.9 +/- 17.2 months. Autograft root dimensions, root distensibility and valve function were assessed by echo-cardiography. The aortic root was measured at the level of the annulus, sinus of valsalva, and sinotubular junction. The distensibility was calculated as percent change of radius. RESULTS: The mean distensibility at the annulus level was higher in group R/A (18.4 +/- 6.8% vs 13.4 +/- 8.1%; p = 0.047); at the level of the sinus of valsalva and sinotubular junction no differences were observed. The autograft pressure gradient was within physiological limits in all patients. The majority of patients showed a competent autograft valve (group R: AI 0 degree; 83%, AI I degree; 14%, AI II degree; 3%; group R/A: AI 0 degree; 75%, AI I degree; 25%). CONCLUSIONS: Replacement of the ascending aorta with a non-compliant prosthesis does not effect root dimension, distensibility, and valve function.

Adult↗
PubMed2003

[Health-related quality of life after heart transplantation].

BACKGROUND: Quality of life late after heart transplantation is reported to be comparable with that of the general population. However, peak exercise capacity remained approximately 60% of what was normal between 1 and 10 years after transplantation. The gap between patients' good quality of life and their impaired exercise tolerance is not yet explained. The purpose of our study was to examine the relation between quality of life and exercise- related variables in heart transplant recipients (HTR). Then, the results of these examinations were compared with those of patients having congestive heart failure (CHF), with the use of controls (C), respectively. METHODS: (Mean values+/-SD) 29 HTR 4.4 +/- 2.1 years after transplantation, 29 CHF (NYHA II n = 22, III n = 7) and 29 C (age 54 +/- 9, 61 +/- 10, 56 +/- 10 years, body mass index 28 +/- 3, 29 +/- 5, 28 +/- 4 kg x m(-2), body fat 25 +/- 4, 27 +/- 6, 26 +/- 5%, respectively) performed cardiopulmonary exercise testing and were interviewed with the standardized German "Quality of life profile for chronic diseases" questionnaire. RESULTS: Peak oxygen consumption was impaired in HTR and in CHF compared with C (19.0 +/- 4.5, 18.6 +/- 4.3, and 30.2 +/- 6.6 ml x min x kg(-1), respectively; p < 0.01 vs. C each). HTR and CHF patients' quality of life in the physical scores were both impaired (p < 0.05 or p < 0.01 vs. C, respectively), but HTRs have reported better scores than CHF (p < 0.05). In the psychological role, CHF was impaired against C (p < 0.05), and HTR scores were comparable with C. In social functioning HTR and CHF patients both showed reduced quality of life dimensions. The Pearson correlation analysis showed that quality of life in physical functioning was related to peak oxygen consumption (p < 0.001) and percentage of predicted workload (p < 0.001). Quality of life in the social and psychological domains showed no association to exercise-related values. CONCLUSIONS: In HTR and in CHF, exercise testing variables were dominant predictors among the physical scales in quality of life, but not among social or psychological scales. Therefore, even late after heart transplantation, improving physical capacity should be a therapeutic goal with the intention of further increasing the quality of life.

Aged↗
PubMed2003

[Phase III rehabilitation after heart transplantation].

INTRODUCTION: Longterm treatment after heart transplantation (HTX) improves survival, although the quality of life and exercise tolerance decreased continuously between one and ten years after transplantation. The role of physical exercise and psychological support in longterm treatment after HTX has not been determined. We analyzed the effects of a one year outpatient rehabilitation program in combination with a home based, computer assisted training program on exercise capacity, coronary risk factors and quality of life. METHODS: 20 heart transplant recipients in an intervention group and 12 patients after HTX in a control group participated in the study (IG (CG); 5.1+/-2.2 (4.5+/-2.3) years after HTX; age: 55+/-7 (54+/-8) years; body mass index: 28.3+/-1.0 (28.7+/-0.9) kg.m(-2)). Before and after the intervention, maximum and constant load exercise capacity, and self-reported quality of life were evaluated. The 12 month intervention period included 10 days of exercise testing as well as medical and psychological support. Furthermore, the IG group performed a computer-assisted and controlled home ergometer training every second day. RESULTS: After one year with 114+/-18 exercise training sessions, maximum oxygen consumption increased in the IG from 18.8+/-4.2 to 20.1+/-4.2 ml.min(-1).kg(-1) (p<0.05; CG 19.3+/- 4.5 to 18.5+/-2.8 ml.min(- 1).kg(-1); p<0.01 IG vs CG). In the IG, lower back pain, body fat, and blood pressure were all reduced, while the self-reported quality of life, endurance exercise capacity and HDL cholesterol were increased. No significant changes occurred in the control group. CONCLUSIONS: When initiated years after heart transplantation, longterm rehabilitation reduced coronary risk factors and significantly improved both the subjects' quality of life, as well as a near to normal capacity for physical work.

Ambulatory Care↗
PubMed2003

[A xenogeneic acellularized matrix for heart valve tissue engineering: in vivo study in a sheep model].

BACKGROUND: The ideal scaffold material for tissue engineered heart valves is discussed controversially. We evaluated acellularized xenogenic matrix constructs with and without seeding with autologous vascular cells in the pulmonary circulation in a sheep model. METHODS: Porcine pulmonary valve conduits (n=16) were acellularized by trypsin/ EDTA incubation. Autologous myofibroblasts and endothelial cells were harvested from carotid arteries; xenogenic valve conduits (n=10) were repopulated with these autologous cells resulting in uniform cellular restitution of the pulmonary valve conduit surface. Using this method, we implanted autologous cell/xenogenic matrix constructs (XB) in ten animals. In six control animals acellularized/xenogenic matrix constructs (XA) were implanted. In each animal, cardiopulmonary bypass was used to resect the pulmonary valve and replace it with the xenogenic pulmonary valve conduits. The animals were killed after 6, 9 or 12 months. The explanted valves were examined histologically and biochemically. RESULTS: After explantation XB showed severe cusp degeneration, which resulted in severe valvular regurgitation. In comparison, XA appeared macroscopically normal with preserved valvular function. The surface of XB were covered with an incomplete endothelial multilayer. The extracellular matrix (ECM) of XB showed pathological amounts of collagenous and elastic fibers as well as proteoglycan content combined with an increase cellularity. The XA were completely repopulated by an endothelial cell monolayer; the ECM was repopulated with a myofibroblast population comparable to native ovine heart valve tissue. CONCLUSIONS: Approaches to heart valve engineering based on acellularized/xenogenic matrices provide promising results and will hopefully led to the "ideal" valve substitute in clinical heart valve replacement.

Animals↗
PubMed2003

Acellularized porcine heart valve scaffolds for heart valve tissue engineering and the risk of cross-species transmission of porcine endogenous retrovirus.

OBJECTIVE: Acellularized porcine heart valve scaffolds have been successfully used for heart valve tissue engineering, creating living functioning heart valve tissue. However, there is concern about the possibility of porcine endogenous retrovirus transmission. In this study we investigated whether acellularized porcine heart valve scaffold causes cross-species transmission of porcine endogenous retrovirus in a sheep model. METHODS: Acellularized porcine pulmonary valve conduits (n = 3) and in vitro autologous repopulated porcine pulmonary valve conduits (n = 5) were implanted into sheep in the pulmonary valve position. Surgery was carried out with cardiopulmonary bypass support. The animals were killed 6 months after the operation. Blood samples were collected regularly up to 6 months after the operation and tested for porcine endogenous retrovirus by means of polymerase chain reaction and reverse transcriptase-polymerase chain reaction. In addition, explanted tissue-engineered heart valves were tested for porcine endogenous retrovirus after 6 month in vivo. RESULTS: Porcine endogenous retrovirus DNA was detectable in acellularized porcine heart valve tissue. However, 6 months after implantation of in vitro and in vivo repopulated acellularized porcine heart valve scaffolds, no porcine endogenous retrovirus sequences were detectable in heart valve tissue and peripheral blood. CONCLUSION: Acellularized porcine matrix scaffolds used for creation of tissue-engineered heart valves do not transmit porcine endogenous retrovirus.

Animals↗
PubMed2003

Pulsatile perfusion and cardiomyocyte viability in a solid three-dimensional matrix.

BACKGROUND: The manufacture of full thickness three-dimensional myocardial grafts by means of tissue engineering is limited by the impeded cellular viability in unperfused in vitro systems. We introduce a novel concept of pulsatile tissue culture perfusion to promote ubiquitous cellular viability and metabolism. METHODS: In a novel bioreactor we established pulsatile flow through the embedded three-dimensional tissue culture. Fibrin glue served as the ground matrix wherein neonatal rat cardiomyocytes were inoculated. Fluor-Deoxy-Glucose-Positron-Emission-Tomography (FDG-PET) and life/dead assays were employed for comparative studies of glucose uptake resp. cell viability. RESULTS: A solid 8 mm thick structure resulted. Cellular viability significantly increased in the perfused chambers. We observed centripetal migration of the embedded cardiomyocytes to the site of the core vessel. However, cellular viability was high in the periphery of the tissue block too. FDG-PET revealed enhanced metabolic activity in perfused chambers. CONCLUSIONS: The present concept is highly effective in enhancing cellular viability and metabolism in a three-dimensional tissue culture environment. It could be utilized for various co-culture systems and the generation of viable tissue grafts.

Animals↗
PubMed2003

Management of lung transplant recipients with bronchogenic carcinoma in the native lung.

Experience with lung transplantation for bronchogenic carcinoma is limited. In our experience, 3 of 6 patients died of recurrent carcinoma within 5 to 35 months after transplantation. Hence, we currently do not support lung transplantation for patients with pre-transplant diagnosis of bronchogenic carcinoma, with the exception of bronchioloalveolar carcinoma (BAC) confined to the lung. Patients with BAC should be staged thoroughly with chest and abdominal computerized tomography, brain magnetic resonance imaging, and bone scan repeated every 3 months while on the waiting list, and should undergo mediastinoscopy at the time of transplantation, with a plan for a backup recipient if metastatic lymph nodes are detected. Proposal for lung transplantation for patients with bronchogenic carcinoma, with the exception of BAC, probably should be performed in the setting of a clinical trial developed with input from the lung transplant community.

Carcinoma, Bronchogenic↗
PubMed2003

Predictors of lung transplant survival in eurotransplant.

This study was undertaken to assess the influence of patient/donor and center factors on lung transplantation outcome. Outcomes of all consecutive first cadaveric lung transplants performed at 21 Eurotransplant centers in 1997-99 were analyzed. The risk-adjusted center effect on mortality was estimated. A Cox model was built including donor and recipient age and gender, primary disease, HLA mismatches, patient's residence, cold ischemic time, donor's cause of death, serum creatinine, type of lung transplant, respiratory support status, clinical condition and percentage predicted FEV1. The center effect was calculated (expressed as the standardized difference between the observed and expected survival rates), and empirical and full Bayes methods were applied to evaluate between-center differences. A total of 590 adults underwent lung transplantation. The primary disease (p=0.01), HLA-mismatches (p = 0.02), clinical condition(p < 0.0001) and the patient's respiratory support status (p = 0.05) were significantly associated with survival. After adjusting for case-mix, no between-center differences could be found. An in-depth empirical Bayes analysis showed the between-center variation to be zero. Similar results were obtained from the full Bayes analysis. Based on these data, there is no scientific basis to support a hypothesis of possible association between center volume and lung survival rates.

Adult↗
PubMed2003

Tissue-engineered bioprosthetic venous valve: a long-term study in sheep.

OBJECTIVE: to develop a graft bearing an immunologically tolerated tissue-engineered venous valve (TE graft) that will be incorporated into a native vessel, and restore normal valve function for the treatment of chronic venous insufficiency. METHODS: twenty-four TE grafts were grown using decellularised allogeneic ovine veins as donor matrix, which was subsequently repopulated with the future recipient's myofibroblasts (MFB) and endothelial cells (EC). TE grafts were implanted into the external jugular vein. Animals were sacrificed at 1, 6, and 12 weeks (n=4, each). Autografts served as controls (1 week, n=4; 6 weeks, n=4). Specimen for histology and immunohistochemistry were taken. RESULTS: the matrix was successfully repopulated with MFB and EC (n=8). Patency on venography in the TE graft-group was44,44, and 34 at 1, 6, and 12 weeks, and44 (44) in autografts at 1 (6) weeks, respectively. Except for 2 TE grafts after 12 weeks, valves were competent (duplex ultrasound). Patent TE grafts were merely distinguishable from autografts with minor inflammatory reactions. Reflux was caused by neo-intima formation related to the basis of the TE graft. CONCLUSION: acellularisation and consecutive in vitro autogeneic re-seeding of valved venous conduits can lead to immunologically acceptable, patent, and competent implants in sheep.

Animals↗