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Biomedical subjects

B Reichart

Publications and source records attributed to B Reichart.

At least 217 records · Page 12Linked to original sources
PubMed1995

Comparison of porcine biological valves with pericardial valves--a 12-year clinical experience with 1123 bio-prostheses.

In order to evaluate selective differences of biological porcine valves versus pericardial valves and to analyze various valve models, 8 different bioprostheses (4 porcine valves, 4 pericardial valves) were studied in a 12-year follow-up. From 1978 to 1990, 476 porcine bioprostheses (Carpentier-Edwards: n = 104, Carpentier Edwards Supraanular: n = 59, Hancock I: n = 41, Hancock II: n = 272) and 647 pericardial valves (Hancock-Extracorporeal: n = 479, Ionescu-Shiley: n = 76, Carpentier-Edwards: n = 57, Mitroflow: n = 35) were implanted. At time of implantation, the patient age ranged from 21-85 years, mean 57.1 +/- 12.4 years. 831 patients were analyzed in the long-term follow-up (62.3 +/- 18.6 months, cumulative follow-up of 6632 patient-years). The incidences of thromboembolic complications (TE), endocarditis (E), primary tissue failure (PTF), rate of reoperation (ReOp), and late mortality due to prosthesis dysfunction were analyzed, calculated, and compared within the different valve models (actuarial data, chi 2 test, log rank analysis). The incidences of TE and E were lower for pericardial valves when compared with porcine bioprostheses (TE: 0.88 vs. 1.8%/patient year; E: 0.24 vs. 0.5%/patient year); within the 2 groups, the different valve models did not show any major differences. However, the incidence of PTF was significantly higher in the pericardial valve group, being 36 +/- 6.5%, 68 +/- 10% and 86 +/- 19.5% after 6, 8, and 10 years; the respective figures for the porcine valves were 6 +/- 3.5%, 18 +/- 7.1%, and 60 +/- 13.1% (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Coronary artery bypass grafting after failed coronary angioplasty: risk factors and long-term results.

In this case-control study we investigated the preoperative risk factors and long-term results in patients undergoing emergency coronary artery bypass grafting (CABG) after failed percutaneous transluminal coronary angioplasty (PTCA). From January 1990 to March 1993, 56 emergency CABGs (Group A) were performed in patients from 7 different cardiology centres--six of these located outside our hospital within a radius of 19 km-1 h to 114 h (phi 7.3 h) after failed PTCA. No special stand-by was given and patients were operated in the next available theatre. Criteria of anatomically unfavourable stenoses for PTCA were defined as follows: Long stenoses, occlusions of other major vessels, tandem stenoses, stenoses at or near a bend or branch and, finally, eccentric stenoses. Thirty-two percent met one criterion, 35.8% two, 6.9% three and 1.8% four criteria. All patients were examined echocardiographically 14.6 +/- 8.2 months postoperatively. Patients who had been operated on electively within the same period served as a control (Group B; n = 56; case-control study). The patients were matched for age, sex, EF, LVEDP, body surface area, reoperation status, and concomitant diseases. The mortality rate for Group A patients was 10.7% (n = 6); for Group B, 1.8% (n = 1). Five of the Group A patients who died came from our own hospital and only one from a hospital 1 km away (mortality: 14.3% vs. 4.8%). There were no deaths among patients with an anatomically favourable stenosis for a PTCA; in patients with more than one criterion for an unfavourable stenosis mortality increased to 19.0% (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1995

Use of the internal mammary artery as a graft in emergency coronary artery bypass grafting after failed PTCA.

The use of the internal mammary artery (IMA) is recommended in elective aorto-coronary bypass grafting (CABG) because of favourable long-term patency results. In emergency CABG many surgeons prefer revascularization only with venous grafts due to the shorter operation time and higher initial flow rates of this type of graft. We investigated whether use of the IMA influences operative and mid-term results of emergency CABG after failed percutaneous transluminal coronary angioplasty (PTCA). From January 1990, to March, 1993, 56 emergency CABGs were performed in patients from 7 different cardiological centres where PTCA had failed. In 23 patients (Group A), the IMA was used as a bypass graft. In most of these patients the left IMA was anastomosed with the left anterior descending artery (n = 19). In one case both IMAs were used as bypass grafts. Venous grafts only were applied in 33 patients (Group B). Due to preparation of the IMA, aortic cross-clamp and bypass times were approximately 15 mins longer in Group A patients, although there was no significant difference in the number of grafts (1.7 +/- 0.8 in Group A vs. 1.5 +/- 0.7 in Group B). All patients of Groups A and B underwent echocardiographical investigations 14.6 +/- 8.2 months postoperatively. The overall mortality in Group A was 13% (n = 3) compared to 9% (n = 3) in Group B (p = 0.58). Significant predictors for death were age 65 years and over, diabetes mellitus, dilatation of the RCX and stenoses unfavourable for PTCA.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1995

The left subclavian vein as an alternative site for implantation of the second defibrillation lead.

The optimal placement for the second defibrillation lead in a two-lead system has never been addressed. We retrospectively reviewed the data of 33 patients with an average age of 59.2 years (range 41-78 years), predominantly male (n = 29), who underwent implantation of a cardioverter defibrillator (ICD) for treatment of ventricular tachycardia (n = 19) or ventricular fibrillation (n = 14). In all patients an attempt was made to implant an endovenous ICD device (leads only, no subcutaneous patch). In group I (n = 18) the defibrillation anode, a separate unipolar lead, was placed in the common position, the superior vena cava. In group II (n = 15) the lead was placed in the left subclavian vein. At least two consecutive shocks reverting ventricular fibrillation at energies < or = 24 J were required for implantation of the ICD device. All shocks were monophasic. The success rate of endovenous defibrillation was significantly higher in group II than in group I (67% vs 28%, P < 0.05). Thus, it could be demonstrated that the position of the defibrillation anode can influence the defibrillation efficacy in transvenous ICD systems. Prospective randomized trials are needed to investigate the optimal position for the second defibrillation electrode, which may gain increasing importance as soon as dual chamber ICDs become available.

Adult↗
PubMed1995

Determinants of dual chamber pulse generators longevity.

The aim of this study was to investigate the effect of battery capacity, internal current drain, and stimulation energy on pulse generators longevity, and if battery impedance measurements can reliably predict pulse generators end-of-life. For this purpose, the records of 577 patients with a mean age of 65 +/- 14 years who had undergone implantation of two different dual chamber pulse generators (PG1: 409; PG2: 168) were retrospectively reviewed. Battery capacity were 2.3 Ah (PG1) and 3.0 Ah (PG2) while current drain at comparable nominal settings was 20 microA (PG1) and 30 microA (PG2) indicating a higher internal current drain of PG2. After a mean follow-up of 46 +/- 23 months, stimulation energy at reprogrammed output settings was significantly higher in PG1 as compared to PG2 (17.1 +/- 0.14) vs 15.5 +/- 0.24 J). Three PG1 (0.7%) and 12 PG2 (7.1%) (P < 0.01) had to be exchanged after a mean of 77.3 +/- 5.3 months (PG1) and 75 +/- 13.5 months (PG2) (P = NS) due to end-of-life being reached. The difference in battery impedances of PG1 and PG2 gained statistical significance 5 years after implantation (1.0 k omega vs 2.4 +/- 6.7 k omega) preceding the significant difference in PG survival after 6 years (98.7 +/- 1.3% vs 90.7 +/- 4.8%). These results indicate that internal current drain is the most important determinant of the pulse generators longevity and that battery impedance can reliably predict end-of-life. Therefore, the essential information about internal current drain should be available for each pacemaker, since it is required for adequate pulse generator selection. Diagnostic functions of dual chamber pulse generators should include measurements of battery impedance.

Adult↗
PubMed1995

[Therapy of hypercholesterolemia after heart transplantation with the HMG-CoA reductase inhibitor simvastatin in long-term follow-up].

The problem of hypercholesterolemia following heart transplantation (HTx) is often underestimated. Up to now there is no concept of therapy allowing an optimal adjustment of lipid parameters. Therapeutical trials using ion exchange resins, derivates of nicotinic acids and fibrates were not successful due to Cyclosporin A interaction, hepatotoxicity and limited efficacy of the applied substances. In a prospective, randomized and controlled trial, we investigated the effects of monotherapy with the HMG-CoA-reductase inhibitor Simvastatin in heart transplant recipients. The study included 70 patients (Simvastatin n = 37, control group n = 33). Eight patients died within the first 3 month postoperatively following HTx. Purpose of the study was adjustment of LDL-cholesterol-values in the Simvastatin-treated group to < 110 mg/dl. Following 24 months of treatment a mean LDL-cholesterol-plasma level of 110 mg/dl was obtained. The corresponding mean value of the control group was 150 mg/dl. The difference between both groups was significant (p < .001). In the same period the mean HDL-cholesterol values increased by approximately 15% in both groups. The ratio of LDL-/HDL-cholesterol was significantly lower in the Simvastatin treated group (2.28) than in the control group (2.94) (p < .01). There was no significant difference in Lp(a)-values. No adverse effects were observed within the following period of 24 months, particularly no increase in the frequency of rejection episodes. The drug induced hypercholesterolemia following HTx could be treated safely and effectively by low-dose Simvastatin.

Adult↗
PubMed1995

Mitral allograft with chordal support: echocardiographic evaluation in sheep.

The in vivo echocardiographic behavior of a new mitral allograft design that incorporates ePTFE patches and chordae to enhance durability has been evaluated in sheep. A strip of pericardium was sewn around the anulus margin and an ePTFE patch of 0.4 mm thickness placed over the truncated papillary muscle tip. In four out of ten cases, 5/0 ePTFE sutures were used additionally to reinforce the native chordae of the anterior leaflet. The allografts were cold-stored at 4 degrees C after antibiotic treatment and implanted in weanling sheep. Valvular function was first examined intraoperatively by transesophageal echocardiography and again after a mean follow up of 153 +/- 8 days by epicardial echo. In all six long term survivors, valve motion was unimpaired and similar to that of the natural mitral valve. There was sufficient coaptation and concentric opening action of the leaflets. Ventricular contraction was enhanced by maintaining the annulo-ventricular connection of the native valve. Color and pulsed Doppler revealed a physiologic biphasic flow pattern and only minor regurgitation in one case. Mean transvalvular pressure gradient was 3.3 +/- 2.1 mmHg on average which correlates well with values obtained from subsequent cardiac catheterization. In conclusion, this new design of a mitral allograft shows excellent in vivo echocardiographic behavior after five months of implantation. Therefore, human allografts of this type could be recommended for clinical application.

Animals↗
PubMed1995

What is the role of lipid lowering therapy in heart-allograft failure?

Hypercholesterolemia is often the cause for the primary heart disease ultimately necessitating heart transplantation (HTx). After transplantation, persisting hypercholesterolemia results in an increased peroxidation of LDL retained by extracellular matrix of the intima. Oxidized LDL accumulates in monocyte derived macrophages, it leads to immobilization of tissue macrophages and provokes the expression of vascular adhesion molecules, growth factors and cytokines. In a prospective open controlled study, the impact of long-term cholesterol reduction by diet in combination with the HMG-CoA-reductase inhibitor Simvastatin on graft vessel disease (GVD) was evaluated. Patients of the control group received only a low fat diet. Simvastatin treatment decreased total and LDL-cholesterol significantly and was not associated with adverse effects. The one year angiographies revealed GVD in 24.1% of the control and 12.1% of the Simvastatin group (Study I). In high risk patients with LDL-cholesterol concentrations above 135 mg/dl, in spite of maximal Simvastatin treatment or plasma fibrinogen concentrations above 400 mg/dl, the heparin mediated extracorporeal low density lipoprotein precipitation (H.E.L.P.)-system was applied. H.E.L.P. was used either for prevention of GVD soon after HTx or for treatment of GVD after development of coronary lesions. Study II proved that the H.E.L.P.-system could significantly lower LDL-cholesterol, Lp(a) and fibrinogen in most high risk patients after HTx, resulting in successful prevention or even treatment of GVD.

Coronary Angiography↗
PubMed1994

Chimeric monoclonal CD4 antibody--a novel immunosuppressant for clinical heart transplantation.

The murine CD4 monoclonal antibody (mAb) M-T412 effectively downregulates T-helper-inducer function, while exhibiting high affinity and specificity for an epitope formed by the V1 and V2 domain of CD4. The antibody was chimerized by combining the murine VH and VL parts to the constant region of a human IgG1 kappa immunoglobulin. This chimeric CD4 monoclonal antibody (chim CD4 mAb) cM-T412 was used for adjunct immunosuppression in addition to standard triple-drug therapy for patients after orthotopic (n = 10) and heterotopic (n = 1) heart transplantation (HTx). cM-T412 was administered intraoperatively and postoperatively on days 1-7, 9, 11, 13, 17, and 21. A control group of similar composition (10 orthotopic, 1 heterotopic HTx) was conventionally treated in an adjunct fashion with antithymocyte globulin (ATG) until cyclosporine (CsA) in serum had reached therapeutic levels. Over the total observation time (mean: 600 days), the number of acute rejection episodes per 100 patient days was 0.26 in the cM-T412 group versus 0.41 in the control group, indicating a reduction of nearly 40%. Four of the 11 patients in the CD4 group have thus far not experienced any rejection crisis compared with two out of 11 in the control group. The mean time to the first rejection episode was 43.7 days in the CD4-treated patients versus 25.3 days in the control group. In addition the interval to the second rejection episode was longer in CD4 patients than in controls. Furthermore, patients treated with chim CD4 mAb had fewer episodes of infection during the first year after HTx (0.49 vs. 0.91 per 100 pt. days) and had a better overall survival rate (91% vs. 73%) than control group pts. No anaphylactic reaction was observed. The only adverse event probably related to cM-T412 infusion was a transient decrease of blood pressure in one patient. Although this study has only a limited number of patients, addition of cM-T412 to standard triple drug therapy appears to be an effective, specific, and well tolerated adjunct to current immunosuppression that offers a new approach for an improved immunomodulatory regimen after heart transplantation.

Adult↗
PubMed1994

[Heart, heart-lung and lung transplantation, 1994 status].

In recent years, heart transplantation has become a clinically routine means of treating patients with terminal cardiac disease. One-year survival rates of more than 80%, and five-year rates of about 70% vindicate the clinical acceptance of this form of treatment. Combined heart and lung transplantation has been practiced for the past ten years. Following the introduction of unilateral and bilateral lung transplantation in 1985, the combined heart/lung approach is now rarely indicated. In the treatment of interstitial, but also pulmonary vascular, diseases, unilateral and bilateral lung transplantation has been increasingly employed. Currently, the one-year survival rate of single-lung transplantation is 70%, that of two-lung or heart-lung transplantation about 60%. The main complications of such procedures remain the high incidence of infection and graft rejection. The lack of availability of suitable donor organs continues to be the major factor limiting the number of transplantations performed.

Cause of Death↗
PubMed1994

[Isolated lung transplantation. Analysis of 17 consecutive operations. Munich Lung Transplant Group].

16 patients (nine men, seven women; mean age 45 [23-62] years) with end-stage pulmonary disease underwent lung transplantation, 14 unilateral, three bilateral (one bilateral retransplantation). The diagnoses were: emphysema (n = 5), idiopathic pulmonary fibrosis (n = 5), emphysema in alpha 1-antitrypsin deficiency (n = 1), mucoviscidosis (n = 1), drug-induced fibrosis (n = 1), chronic lung rejection after heart-lung transplantation (n = 1), secondary pulmonary hypertension with persistent ductus arteriosus (n = 1), sarcoidosis (n = 1) and chronic transplant failure after unilateral transplantation (n = 1). Eleven patients survived long-term (mean follow-up period 247 [8-585] days). Ten of these patients have been independent of additional oxygen after an average of 8 months postoperatively, eight are physically active according to their age. Three patients died of reperfusion damage intraoperatively or in the early postoperative period. The two other patients died from septicaemia 5 1/2 and 7 months postoperatively. It is concluded that lung transplantation in end-stage pulmonary disease provides the only therapeutic means with any expectation of physical rehabilitation.

Activities of Daily Living↗