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Biomedical subjects

A Haverich

Publications and source records attributed to A Haverich.

At least 307 records · Page 17Linked to original sources
PubMed1993

Third-time coronary artery revascularization.

Eighteen patients underwent a third coronary artery revascularization (rere-CABG) between 1983 and 1991. The factors necessitating rere-CABG were graft failure in 83% of the patients and progression of native coronary atherosclerosis in 17%. Mean interval between the second and third operation was 49.1 months. Median sternotomy and cardiopulmonary bypass (CPB) were used in 12 patients, a left thoracotomy approach was used in 6 (with CPB in 3 patients and without CPB in 3). The mean revascularization rate was 2.2 (grafts/patient). The internal thoracic artery was employed in 12 patients and the right gastroepiploic artery was used in one. Operative mortality was 11.1% (2 deaths). Non-fatal perioperative myocardial infarction, reexploration for bleeding, and respiratory failure occurred in one patient each. There were no other serious complications. Long-term follow-up was obtained in 15 of the 16 survivors. Four patients had recurrence of angina pectoris, and one late death due to myocardial infarction occurred. The myocardial event-free rate was 75% at 3.4 years. This experience indicates that a third coronary revascularization can be justified: operative approach and choice of graft material have to be individualized, but adequate long-term results can be obtained.

Aged↗
PubMed1993

Comparative in vivo study on the healing qualities of four different presealed vascular prostheses.

PURPOSE: The purpose of this article is to assess the healing qualities of presealed knitted polyester prostheses. METHODS: Thoracic aortic replacement was performed with grafts with four different coating materials-collagen (CP), albumin (AP), and two with gelatin (GP1/GP2)-in four groups of 15 pigs each. Two weeks, 6 weeks, and 6 months after operation, five pigs of each group were killed. Healing quality was assessed by morphometric analysis of the remaining coating, the extent of tissue ingrowth, and the thickness of the inner layer. RESULTS: The sealant was rapidly absorbed in all prostheses except for the AP (remaining coating at 2 weeks: GP1 22.1%, GP2 34.7%, and CP 68.0% vs AP 97.1% [p < 0.05]), remaining coating at 6 weeks: GP1/GP2 0% and CP 2.5% vs AP 76.7% (p < .01). At 6 months, remaining coating was only detectable in AP (21.5%). At 2 weeks the extent of tissue ingrowth ranged from 65.7% in GP1 and 75.3% in CP to 80% in GP2 versus 8.9% in AP (p < 0.05). There was a slow increase of tissue ingrowth until the sixth postoperative week (GP1 74.4%, GP2 85.0%, and CP 91.3% versus AP 19.6% [p < 0.01]). Thickness of the internal layer varied from 0.11 to 0.21 mm at 2 weeks in all grafts studied and from 1.02 mm (AP) and 1.28 mm (GP2) to 1.39 mm (GP1), versus 0.41 mm in the CP (p < 0.01) after 6 months of implantation. CONCLUSIONS: The type of coating significantly influences the healing properties of knitted polyester prostheses. When used for thoracic aortic replacement in pigs, AP coating clearly results in inferior healing compared with GP1/GP2 or CP impregnation, with digestion of the coating material and tissue ingrowth used as parameters. The thinnest internal layer was found in the CP prostheses, reflecting superior healing properties of this coating in the model studied.

Absorption↗
PubMed1993

De novo expression of MHC class I and class II antigens on endomyocardial biopsies from patients with inflammatory heart disease and rejection following heart transplantation.

Inflammation of the heart muscle is caused either by infection (i.e. coxsackie virus) resulting in myocarditis or by rejection following heart transplantation. These processes induce activation of the immune system. We examined endomyocardial biopsies from patients with myocarditis, perimyocarditis and rejection following heart transplantation and compared these to biopsies from patients with coronary artery disease. The biopsies were examined immunohistologically with specific monoclonal antibodies against class I and class II molecules of the major histocompatibility complex (MHC). MHC class I antigens on the normally negative myocytes were evident in myocarditis (38%) and in rejection after heart transplantation (68%). In the interstitium there was an increase of both MHC class I and class II antigens. MHC class II antigens, however, were never seen on myocytes. MHC class I antigens are required for the action of CD 8 positive cytotoxic T cells. Therefore myocytes which express MHC class I antigens are susceptible to cytotoxic effects of the immune system. MHC class II antigens are essential to T helper cells. By cytokine release, activated T helper cells play a central role in the initiation, regulation and mediation of an immune response in myocarditis and rejection following heart transplantation.

Biopsy↗
PubMed1993

[Post-traumatic ARDS--a potential indication for lung transplantation?].

Posttraumatic adult respiratory distress syndrome (ARDS) still involves significant mortality, despite progress in management concepts. Current therapeutic strategies are briefly described, including kinetic therapy, high-frequency jet ventilation and extracorporeal membrane oxygenation. In addition, a spectacular case of the first successful lung transplantation for posttraumatic ARDS after failed ECMO (extracorporeal membrane oxygenation) support is reported. This young man with severe posttraumatic ARDS developed a potentially lethal bilateral pulmonary hemorrhage under treatment with ECMO, and on the basis of this bilateral pulmonary transplantation was considered to be indicated. The patient is alive and well 2 years after the procedure.

Adult↗
PubMed1993

Bronchial circulation after experimental lung transplantation. The effect of long-term administration of prednisolone.

The effect of corticosteroids on bronchial healing after modified left lung transplantation was investigated in pigs. In groups I (n = 6) and II (n = 6), animals received cyclosporine (15 mg/kg per day) and azathioprine (2 mg/kg per day). In group II, prednisolone (1 mg/kg per day) was also administered. Bronchial blood flow was estimated at the donor carina and donor second carina with laser Doppler velocimetry and radioisotopes 7 days postoperatively; macroscopic and microscopic assessments of graft airways were performed. Bronchial blood was calculated relative to the recipient carina. In group II, bronchial blood flow at the donor carina and donor second carina was significantly higher than that of group I. Macroscopic assessment revealed more pronounced ischemic changes in group I (5 of 6 animals) than in group II (2 of 6 animals, p = not significant). Microscopically, airway samples from the donor carina revealed marked destructive changes in five of six animals in group I. In group II, only mild ischemic changes, which were limited to the respiratory epithelium, were seen. We concluded that the administration of prednisolone results in improved bronchial blood flow and decreased bronchial ischemia after lung transplantation.

Animals↗
PubMed1992

Myocardial preservation with the UW solution. First European results in clinical heart transplantation.

In recent years, there is a growing body of evidence that the University of Wisconsin (UW) solution offers many advantages in organ preservation with regard to preservation quality and time. We, therefore, conducted the first European prospective, randomized, clinical trial comparing myocardial performance after preservation with UW and St. Thomas Hospital (ST) solution. Preliminary results indicated superior heart function after preservation with UW solution.

Adenosine↗
PubMed1992

Antagonisation of platelet activating factor--a new therapeutic concept for improvement of organ quality in lung preservation.

The release of platelet activating factor (PAF) is thought to be one of the most important pathophysiological pathways in the development of ischemic lung injury. We investigated the use of a PAF antagonist (PAF-a) in a canine model in reducing PAF-mediated pulmonary dysfunction following lung preservation and transplantation. Twelve combined heterotopic heart and orthotopic left lung allotransplantations were performed after 6 h of cold ischemia. Following administration of prostacyclin (PGI2), Euro-Collins solution (EC) was used for pulmonary artery flush in all donors, while in six animals the PAF-a, WEB 2170 BS, was administered to the donor (0.15 mg/kg for 30 min), to the storage solution (0.3 mg/kg) and to the recipient during reperfusion for a total of 6 h (0.3 mg/kg per h) EC/PAF-a). In all donors myocardial preservation was achieved using St. Thomas Hospital solution. Postoperatively, cardiorespiratory function was evaluated separately for donor and recipient organs at an FiO2 of 0.4 for a maximum of 12 h. The quality of lung preservation was assessed by means of postoperative oxygenation (pO2), pulmonary artery pressure (PAP) and pulmonary vascular resistance index (PVRI). In the EC/PAF-a group, pO2 of the donor lung was significantly elevated (P < 0.01) and PVRI was significantly lower (P < 0.05) when compared to the EC group, while PAP showed no significant differences between both groups and throughout the entire postoperative course. We concluded that a significant improvement in the current clinical standard for lung preservation could be obtained by the application of WEB 2170 BS in combination with EC flush as demonstrated by improved oxygenation and lower PVRI of the transplantated organs.

Animals↗
PubMed1992

Thoracic organ transplantation in the paediatric age group. The Hannover experience.

Growing experience in terms of immunosuppression, recipient and donor selection as well as organ preservation has established thoracic organ transplantation as a therapeutic option for many children with end-stage cardiopulmonary diseases. While dilated cardiomyopathy and isolated myocardial failure represent the main indications for cardiac transplantation, replacement of the lungs or heart and lungs is necessitated in cystic fibrosis, primary and secondary pulmonary hypertension as well as some types of complex congenital heart defects involving the pulmonary arteries. We have performed a total of 20 heart, 4 heart-lung, 2 single lung and 1 double lung transplantation in the paediatric group up to 17 years of age. While with respect to the limited experience worldwide, early mortality after lung and heart-lung transplantation is still high (50%), long-term results in isolated cardiac transplantation using triple drug immunosuppression are excellent (79% survival after 6 years) without major impairment of renal function, arterial blood pressure, growth development and physical rehabilitation as well as social reintegration. Freedom from graft atherosclerosis of the allografted heart is documented over a 5 year follow up, while no data are available on the incidence of obliterative bronchiolitis after lung transplantation in the paediatric group. Despite only limited evidence of long-term dysfunction, diagnosis and prevention of chronic rejection should be given utmost attention to allow for a normal life span in this younger age group.

Adolescent↗
PubMed1992

Nifedipine and diltiazem reduce pulmonary edema formation during postischemic reperfusion of the rabbit lung.

A protective effect of calcium antagonists in pulmonary preservation for transplantation has been observed recently. This report focuses on the potential use of diltiazem and nifedipine in the early phase of reperfusion after normothermic pulmonary ischemia. Rabbits weighing 4-5 kg were tracheotomized and ventilated with 50% oxygen. In a control group (group I, n = 7), the hilus of the right lung was clamped for 210 min without ischemia of the left lung. Lung ischemia was created in a second group (n = 7) by clamping the left hilum for 2 h. Subsequently, reperfusion of the left lung was maintained for 210 min, while the right hilus was kept occluded. In group III (n = 6) and group IV (n = 8) the conditions were the same as in group II, but either diltiazem (62.5 micrograms/kg i.v., group III) or nifedipine (3 micrograms/kg i.v., group IV) was administered during the first 20 min of reperfusion. After 210 min of reperfusion, the pulmonary vascular resistance was elevated in group II (mean: 5120 dyn.sec.cm-5), group III (5518 dyn.sec.cm-5), and group IV (4324 dyn.sec.cm-5) compared with group I (3390; n.s.). Arterial oxygenation showed no significant differences among group I (mean: 257 mmHg), group II (261 mmHg), group III (208 mmHg), and group IV (247 mmHg). Pulmonary ischemia resulted in an increased extravascular lung water content in group II as compared to group I (73 and 64 g/g wet weight; P less than 0.0125 vs group I). No such increase was seen in groups III and IV (53 and 54 g/g wet weight respectively; P less than 0.001 vs group II).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Changes in cardiac beta 1- and beta 2-adrenoceptor densities after human cardiac transplantation: relation to transplant coronary vasculopathy and pretransplantation disease.

In 100 patients 12 to 60 months after cardiac transplantation, the influence of transplant coronary vasculopathy and of the pretransplantation disease (end-stage heart failure caused by coronary artery disease or dilated cardiomyopathy) on the beta-adrenergic receptor (AR) numbers and beta 1/beta 2-AR ratio of right ventricular biopsies was determined. Patients with coronary vasculopathy (CVP) after cardiac transplantation had lower absolute numbers of beta 1-AR compared with patients without CVP. Since patients with CVP had increased left ventricular (LV) end-diastolic pressure and LV muscle mass, it is suggested that decreased beta 1-AR may be the result of an altered hemodynamic situation of the transplanted heart after development of CVP. Patients with dilated cardiomyopathy (DCM) before cardiac transplantation showed a decrease in total beta-AR and of the beta 1/beta 2-AR ratio as a result of an increase in beta 2-AR and a decrease in beta 1-AR numbers. The decreased beta 1/beta 2-AR ratio in patients with previous DCM may indicate that the beta-AR system of the transplanted heart might be influenced (at least in part) by pathophysiologic factors that are characteristic of the pretransplantation disease ultimately leading to cardiac transplantation and persisting after cardiac transplantation.

Adult↗
PubMed1992

University of Wisconsin versus modified Euro-Collins solution for lung preservation.

In a canine model, the quality of lung preservation was assessed using pulmonary artery flush after prostacyclin administration with either modified Euro-Collins solution or University of Wisconsin solution. Twelve combined heterotopic heart and orthotopic left lung allotransplantations were performed after 6 hours of cold ischemia. Myocardial preservation was achieved using St. Thomas Hospital solution. Donor organs were anastomosed parallel to the recipient's heart and right lung, and the superior vena cava inflow was directed into the transplanted heart-left lung block after ligation of the recipient's superior vena cava proximal to the caval anastomosis. Postoperatively, cardiorespiratory function was evaluated separately for donor and recipient organs at an inspired oxygen fraction of 0.4 for a maximum of 12 hours. Significantly improved oxygenation and lower pulmonary vascular resistance index of the donor lung was observed in the University of Wisconsin + prostacyclin group, whereas pulmonary artery pressures showed no significant differences in between both groups. It is concluded that superior results in lung preservation can be achieved with pulmonary artery flush perfusion using University of Wisconsin solution and prostacyclin when compared with Euro-Collins solution and prostacyclin.

Adenosine↗
PubMed1992

Predictive criteria for the need of extracorporeal circulation in single-lung transplantation.

Use of extracorporeal circulation is mandatory in heart-lung and en bloc double-lung transplantation. However, no criteria exist to predict the necessity of its application during single-lung transplantation for parenchymal lung diseases. We therefore reviewed our experience in 23 patients undergoing single-lung transplantation for idiopathic pulmonary fibrosis. All patients were evaluated by preoperative right heart catheterization. For intraoperative monitoring, a pulmonary artery thermodilution catheter was placed in the contralateral lung to repeatedly assess pulmonary artery pressure, cardiac output, and pulmonary vascular resistance. Extracorporeal circulation was necessary during graft implantation in 4 patients, whereas 19 patients underwent operation without it. Preoperative demographic patient data, time of ischemia, and hemodynamic values obtained preoperatively and before the clamping of the pulmonary artery showed no significant differences between groups. In contrast, after the clamping of the pulmonary artery, a significant drop in cardiac index of about 1.5 L.min-1.m-2 (p less than 0.01) and a concomitant rise in pulmonary vascular resistance (p less than 0.01) was observed in the group requiring extracorporeal circulation, whereas these variables showed no significant changes in the other 19 patients. Pulmonary artery pressure rose significantly in both groups (p less than 0.05), without significant differences between them. It is concluded that intraoperative assessment of cardiac index and pulmonary vascular resistance is essential for estimation of cardiac performance during single-lung transplantation. A decrease in cardiac index of more than 1.5 L.min-1.m-2 after the clamping of the pulmonary artery rather than the degree of pulmonary hypertension is indicative of the need of extracorporeal circulation.

Adult↗
PubMed1992

Systemic recombinant tissue plasminogen activator lysis for left atrial thrombus formation after single-lung retransplantation.

This report describes a recipient of single-lung transplantation surviving extraordinary complications: (1) early graft failure mandating retransplantation; (2) left atrial thrombus formation, which resolved by recombinant tissue plasminogen activator lysis; (3) and development of a "locked-in-syndrome." Possible underlying mechanisms are discussed.

Extracorporeal Membrane Oxygenation↗
PubMed1992

Decrease in beta 1- and increase in beta 2-adrenoceptors in long-term follow-up after orthotopic cardiac transplantation.

Total beta 1- and beta 2- subtype distribution were examined in right ventricular biopsies taken from 100 patients 1-60 months after orthotopic cardiac transplantation and from eight prospective transplant donor hearts serving as controls. The patients were classified into eight groups depending on the time after transplantation that the biopsies were taken: 1-3 (n = 15), 4-7 (n = 15), 8-11 (n = 6), 12 (n = 15), 24 (n = 15), 36 (n = 12), 48 (n = 12) and 60 months (n = 10). The non-selective beta-adrenoceptor antagonist (-)-[125I]-iodocyanopindolol (ICYP) was used as a radioligand to assess total beta-adrenoceptor density. The beta 1- and beta 2-subtype distribution was determined with a beta 1-adrenoceptor saturating concentration of the selective beta 1-adrenoceptor antagonist CGP 20712A (300 nmol/l). In transplant donor hearts the total beta-adrenoceptor density was found to be 70.8 +/- 7.1 fmol/mg protein including a beta 1:beta 2-adrenoceptor ratio of about 80:20%. Until 36 months after cardiac transplantation the total number of beta-adrenoceptors showed no significant change. A slight but insignificant decrease was observed after 48 (16.2%) and 60 (21.2%) months. In contrast, from 12 to 60 months after cardiac transplantation the beta 1:beta 2-adrenoceptor ratio was shifted significantly (66:33% to 61:39%) as compared with transplant donor hearts which was due to an increase in beta 2- and a decrease in beta 1-adrenoceptor number. Thus, the surgically denervated, transplanted human heart exhibits a beta 2-adrenoceptor up-regulation during long-term follow-up. It is suggested that this up-regulation of the beta 2-adrenoceptor subtype could be owing to an increased importance of circulating catecholamines in modulating positive chronotropic and inotropic effects.

Adult↗
PubMed1992

Prolonged myocardial protection with St. Thomas' Hospital solution and University of Wisconsin solution. The importance of preservation techniques.

The effectiveness of University of Wisconsin solution (UWS) and oxygenated St. Thomas' Hospital solution (STS) for prolonged myocardial protection was evaluated in isolated working rat hearts preserved for 12 h at 4 degrees C using three different preservation techniques: induction of cardiac arrest and subsequent hypothermic storage with STS (group 1, n = 9) or UWS (group 4, n = 9), intermittent coronary flush (every 90 min) with STS (group 2, n = 9) or UWS (group 5, n = 9), or continuous coronary perfusion with STS (group 2, n = 7) or UWS (group 6, n = 7) before 60 min of reperfusion. In the UWS preserved hearts, recovery of aortic flow was greater when the simple storage technique was employed compared to intermittent or continuous coronary perfusion (groups 5 and 6). In the STS preserved hearts, aortic flow recovery was superior when the intermittent perfusion technique was applied. The same pattern was observed with regard to recovery of left ventricular pressure. Lactate dehydrogenase release during reperfusion was significantly less pronounced in group 4 (UWS, single flush, simple storage) as compared to group 1 (STS, single flush and simple storage), whereas best preservation of myocardial high energy phosphates was observed when hearts were preserved with multiple dose cardioplegia using STS. Simple hypothermic storage with UWS affords the best functional recovery after prolonged myocardial ischemia in all groups. Repetitive or continuous application of this solution is detrimental, possibly due to potassium overloading. In STS treated groups, multiple dose application of oxygenated STS enhances functional and metabolic recovery compared to its single dose application.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗