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Biomedical subjects

H H Scheld

Publications and source records attributed to H H Scheld.

At least 109 records · Page 6Linked to original sources
PubMed2000

The bad ventricle--revascularization versus transplantation.

BACKGROUND: The proportion of patients with left-ventricular dysfunction (LVD) undergoing high risk revascularization is increasing. In this patient group, the perioperative risk is elevated because of the pre-existing pathophysiology. Detailed evaluation and interdisciplinary differential therapeutic considerations on the basis of the comparative benefit rationale, with cardiac transplantation alternative, is mandatory. METHODS: Among 7275 patients who underwent coronary artery bypass grafting between 1990 and 1998 in our institution, we found 51 patients who had had an ejection fraction <20%, and thus were candidates for transplantation (group CABG); these were compared with 163 patients who were listed for cardiac transplantation because of ischemic cardiomyopathy (group HTX). The survival analysis was performed on the basis of the intention-to-treat principle independent of subsequent transplantation. RESULTS: Both groups were comparable with regard to left-ventricular ejection fraction; pulmonary capillary wedge pressure and serum creatinine, but patients in the CAGB group were older (63+/-11 vs 56+/-8; p = 0.001) and included a higher percentage of women (m/f: 42/9 vs 152/11; p = 0.03). Nevertheless, there was a similar 1-year survival in both groups (group BP 71.9% vs group HTX 66.3%; p = ns). Looking at the CABG group, the internal thoracic artery was used in 36/51 patients, an intra-aortic balloon pump was used preoperatively in 26 patients, and intraoperatively in 6. Left-ventricular assist devices had to be inserted in three patients, extracorporeal membrane oxygenation once. Perioperative (30 day) survival was 88.2 %. An elevated preoperative serum creatinine and the nonusage of the internal thoracic artery predicted an adverse outcome. In the long-term course, the NYHA functional class improved in most cases from III preoperatively to I after 26 (2-66) months. CONCLUSION: We conclude that patients with ischemic cardiomyopathy, viable myocardium, and graftable vessels can be revascularized with acceptable risk. Since for these patients a standby of mechanical circulatory support must be anticipated perioperatively, this infrastructure should be established within the center.

Aged↗
PubMed2000

Small thymomas and myasthenia gravis: a poorly understood association.

Myasthenia gravis (MG) is associated with about 20% of all patients with thymomas, but the occurrence in patients with small thymomas is rare. The pathogenetic relevance of these small thymomas for MG is poorly understood until now. We report on the clinical course of a 39-year-old female patient suffering from MG and undergoing thymectomy for a small thymoma and discuss the pathogenetic importance of small thymomas for MG.

Adult↗
PubMed2000

Ploidy, expression of erbB1, erbB2, P53 and amplification of erbB1, erbB2 and erbB3 in non-small cell lung cancer.

The aim of this study was to assess the prognostic value of deoxyribonucleic acid analysis, expression oferbB1, erbB2 and P53, and amplification levels of erbB1, erbB2 and erbB3 in non-small cell lung cancer (NSCLC). Consecutive patients with NSCLC who underwent treatment with curative intention (118) were included. In 108 cases, the cell cycle was analysed using flow cytometry and double-staining with propidium iodide and anticytokeratin. In another 108 cases, expression of erbB1, erbB2 and P53 was assessed immunhistochemically. Amplification of the erbB family was determined in the tumours of 53 patients using double-differential polymerase chain reaction. Of the tumours, 81% were aneuploid and 14% showed positive staining for erbB1, 18% for erbB2 and 41% for P53. There were normal mean gene copy numbers in 86% for erbB1, 94% for erbB2 and in 96% for erbB3. No significant correlations were noted between erbB1, erbB2 and P53 expression, ploidy status and tumour stage. In a Cox regression model, only tumour stage was shown to be prognostically significant. It seems that ploidy and expression status of erbB1, erbB2 and P53 are not prognostic parameters in non-small cell lung cancer. Amplification of the erbB family does not seem to be a frequent event in non-small cell lung cancer.

Adenocarcinoma↗
PubMed1999

Ambulatory care of patients with left ventricular assist devices.

BACKGROUND: Left ventricular assist devices (LVAD) have revolutionized the treatment of patients with acute and chronic heart failure as they provide a high quality of life. We report on our experience with patients receiving ambulatory care after LVAD implantation. METHODS AND RESULTS: Since July 1995, 46 patients with a mean age of 45+/-11 years underwent implantation of an electrically driven LVAD with portable controller and batteries. Sixteen (35%) patients bridged >30 days were treated in part on an outpatient basis. After LVAD implantation, they were treated in the hospital for 86+/-32 days (range 40 to 153 days). Afterward, they received ambulatory care for 74+/-76 days (range 2 to 301 days, total experience 1206 days). In 13 cases, the outpatient treatment was interrupted by 1.7+/-1.7 readmissions, for a total of 32+/-42 days (median 19 days). Reasons for readmission included systemic or drive line infections (incidence 0.0066 per outpatient day), suspected or true thromboembolic events (incidence 0.0066 per outpatient day), and suspected malfunction of the LVAD. One patient supported as alternative to transplantation died after cerebral bleeding after 244 days, 1 patient with a history of acute myocarditis had ventricular fibrillation during LVAD assist while being at home for 177 days and died in a low output state, 10 patients were given transplantation after a mean support interval of 206+/-88 days, and 4 patients currently await heart transplantation. CONCLUSIONS: Outpatient treatment after LVAD implantation is feasible, and severe complications are uncommon.

Adult↗
PubMed1999

Fetoscopic transesophageal electrocardiography and stimulation in fetal sheep: a minimally invasive approach aimed at diagnosis and termination of therapy-refractory supraventricular tachycardias in human fetuses.

BACKGROUND: Therapy-refractory supraventricular tachycardia commonly results in hydrops and death in human fetuses. The purpose of this study in fetal sheep was to assess the feasibility of a minimally invasive fetoscopic approach for fetal transesophageal electrocardiography and stimulation aimed at diagnosis and termination of these tachycardias. METHODS AND RESULTS: We studied a total of 10 fetal sheep (87 to 103 days of gestation; term=145 days). We entered the amniotic cavity using a percutaneous fetoscopic approach and placed various electrophysiology catheters into the fetal esophagus. We recorded the number of animals in which fetoscopic transesophageal electrocardiography and stimulation were successful and assessed pacing success and thresholds for different catheters. In addition, we monitored for potential adverse effects from stimulation and for other complications of the operation. Recording of transesophageal electrocardiograms was successful in all fetal sheep. Capture during stimulation was successfully documented by additional fetal bipolar surface electrocardiograms in 7 fetuses. In fetuses in which fetal surface electrocardiograms were not recorded, pacing stimulus artifacts interfered with documentation of capture. Although stimulation thresholds were high, the maternal rhythm was not affected by fetal stimulation. CONCLUSIONS: Fetoscopic fetal transesophageal electrocardiography and stimulation are feasible in fetal sheep. This minimally invasive approach might have the potential to improve diagnosis and management of therapy-refractory supraventricular tachycardias in human fetuses.

Animals↗
PubMed1999

Combining nonpharmacologic therapies for advanced heart failure: the Münster experience with the assist device-defibrillator combination.

Implantable cardioverter defibrillators (ICDs) and ventricular assist devices (VADs) have been used as a bridge to cardiac transplantation. In selected patients, the combined implantation may be required. This study was motivated by a case of a 33-year-old female patient with giant cell myocarditis who died of ventricular tachyarrhythmias after having been placed on a VAD with which she had been treated on an out-of-hospital basis for a prolonged period of time. A subsequent retrospective analysis of our data showed that, of 73 patients who had to be bridged mechanically (54 Novacor, 12 TCI Heartmate, 4 Thoratec, 3 Medos) in our institution between 1993 and 1998, 10 patients had undergone defibrillator implantation either before (n = 8) or after (n = 2) implantation of a VAD. The cases are presented, and the feasibility of the combination therapy discussed.

Adult↗
PubMed1999

Impact of local donor and regionalization on a German transplantation center. UNI NRW. Universities of North Rhine Westfalia.

Optimal allocation of donor organs is an ongoing matter of debate. We report on the impact of the foundation of UNI NRW, a close transplant collaboration of seven university centers with the intention of improving donor organ allocation, on the heart transplant program in Münster. All donor organs retrieved were offered first to the patients within this region before going into the Eurotransplant (ET) Foundation pool. The heart transplant program data were prospectively (for 1997) and retrospectively (for 1996) analyzed with regard to donor organ availability and allocation. There was a slight decrease in the number of donor hearts offered and accepted within the UNI NRW region in 1997 as compared to in 1996. However, due to the significantly lower organ export rate, the number of heart transplantations performed in UNI NRW rose from 47 to 72 procedures. In Münster, only six donor organs (16%) were procured from outside UNI NRW in 1997, and these were, in part, due to special urgency requests. In conclusion, the institutionalization of UNI NRW within the framework of ET offers more flexibility, decreases total ischemic time, and may help to lower costs.

Europe↗
PubMed1999

On the contractile function of protein phosphatases in isolated human coronary arteries.

It is unknown whether protein phosphatases types 1 and 2A are present in and can regulate the tone of human vascular tissue. The expression and possible function of serine/threonine protein phosphatases (PP) type 1 (PP1) and type 2A (PP2A) were studied in isolated human coronary arteries. Catalytic subunits of PPI and PP2A were identified by means of phosphatase activity measurement in tissue homogenates, by separation of enriched extracts through affinity column chromatography, by immunoblotting with specific antibodies, by hybridization of mRNA with specific DNA probes and PCR of reverse transcribed mRNA. Based on these methods, the catalytic subunits of PP1(alpha,beta,gamma) and PP2A(alpha,beta) were identified. Appropriately, cantharidin, an inhibitor of PP1 and PP2A, increased basal tone of human isolated coronary artery rings with an EC50 of about 16 micromol/l by increasing the phosphorylation state of the regulatory light chains of myosin. In summary, PP1 and PP2A are expressed in human coronary arteries and they can alter vascular tone.

Chromatography, Affinity↗
PubMed1999

Heart transplants--assessment of dental procedures.

The object of this study was to evaluate the effects of dental foci on survival rates and rejection episodes in heart transplant recipients. Therefore, in a retrospective longitudinal study we studied 74 heart transplant recipients at the Department of Maxillofacial Surgery and Department of Thoracic and Cardiovascular Surgery, University of Münster. Study patients were divided into groups: those in which dental foci had been verified (n = 31) and those without dental foci (n = 43). Statistical analysis was performed using the chi-square test, Kaplan-Meier life table analysis, and the log-rank test. Before heart transplantation, patients were screened clinically and radiographically to determine the extent of dental foci. Postoperatively, patients were evaluated dentally and medically to identify the impact of dental foci on the incidence of systemic and oral infections, frequency and severity of rejection episodes, mortality, and complications arising during dental treatment. By comparing the mortality, infection and rejection rates in the various groups no statistically significant differences (P > 0.05) were found between patients. Despite immunosuppression, extended inflammatory processes such as abscess formation or viral stomatitis were not found in the oral cavity. We therefore suggest that patients suffering from the symptoms of severe heart failure need not be subjected to rigorous preoperative dental treatment.

Bacteremia↗
PubMed1999

Anastomosis to the wrong vessel during off-pump bypass surgery via mini-thoracotomy.

Recently, minimally invasive coronary artery bypass graft operation has been established as a new treatment strategy for cardiac surgeons. We report on a patient who underwent off-pump coronary artery bypass graft operation through a mini-thoracotomy to the wrong coronary artery (first diagonal) with consecutive successful percutaneous transluminal coronary angioplasty of the vessel involved (left anterior descending coronary artery) to demonstrate a special risk that is associated with this kind of operation.

Adult↗
PubMed1999

Coronary artery bypass grafting with an expanded polytetrafluoroethylene graft.

BACKGROUND: We report our experience with the Perma-Flow aortocoronary-right heart graft in 15 patients in whom autologous conduits were not available. METHODS: Fifteen patients received 39 coronary anastomoses--10 to left anterior descending coronary artery branches, 15 to circumflex coronary artery branches, and 14 to branches of the right coronary artery. Early angiography was done in 11 patients. RESULTS: One patient died on postoperative day 17 of multiorgan failure. The graft was patent at postmortem examination. Of 30 coronary anastomoses at risk, 24 were patent. Three connections to the left anterior descending system were occluded in patients with an additional internal mammary artery graft to the same coronary system, and three connections to the circumflex system were occluded in patients with a history of major posterior infarction. Three of five distal anastomoses to the right atrial appendage were occluded, whereas all six connections to the superior vena cava were patent. None of the patients had shown recurrent angina at a mean follow-up of 10.9 months (range, 2-39 months). CONCLUSIONS: The synthetic Perma-Flow coronary graft appears to be a safe alternative in patients in whom arterial or venous conduits are not available. Competitive flow may lead to anastomotic occlusions. The appropriate site for the distal arteriovenous fistula seems to be the superior vena cava.

Blood Vessel Prosthesis↗
PubMed1999

Overexpression of tissue-type plasminogen activator in atherosclerotic human coronary arteries.

UNLABELLED: The plasminogen activator (PA)/plasmin system is involved in various pathological processes that are considered important features of atherogenesis and atherothrombosis. These include the proteolysis of fibrin deposits and extracellular matrix components as well as the induction of cell migration and mitogenesis. Tissue-type PA (TPA) is a key enzyme mediating plasminogen to plasmin conversion. TPA plasma concentrations are elevated in patients with advanced atherosclerosis and correlate with an increased risk for myocardial infarction and stroke. In this study, we have analysed the content and expression of TPA in human coronary arteries and their relation to the presence and severity of atherosclerotic lesions. METHODS: Segments of coronary arteries obtained from heart explants (n = 15) were classified by the presence and types of atherosclerotic lesions. TPA was quantitatively determined in protein extracts of intimal and medial layers. In situ hybridization and immunohistochemical analyses were performed on serial sections of representative tissue specimens. RESULTS: PA activity entirely attributable to the presence of active TPA was consistently detected in the protein extracts. Extractable TPA antigen and activity showed a significant graded increase in relation to the presence and severity of atherosclerotic lesions. The ratios of active over total TPA were increased several-fold in extracts of advanced lesions despite a concomitant threefold increase in TPA complexed to its inhibitor PA-1. In macroscopically normal arterial segments and in early lesions, TPA was expressed in the endothelium and in colocalization with vascular smooth muscle cells (VSMCs). In advanced plaques, TPA mRNA was mainly detected in the lateral regions of the fibrous caps in association with migrating VSMCs and in the vicinity of the core areas infiltrated by CD68-positive macrophages. CONCLUSIONS: TPA content and expression is consistently increased in relation to the severity of the lesions in atherosclerotic coronary arteries. This may contribute to plaque destabilization and disruption. Conversely, the increased intramural TPA activity may counteract mural fibrin deposition.

Arteries↗
PubMed1999

Fetal transesophageal echocardiography utilizing a 10-F, 10-MHz intravascular ultrasound catheter--comparison with conventional maternal transabdominal fetal echocardiography in sheep.

The purpose of our study in fetal sheep was to assess the measurement agreement between fetal transesophageal echocardiography (FTEE) and conventional maternal transabdominal echocardiography (CMTFE) by the Bland-Altman method. We performed our study in 11 fetal sheep between 95-103 days of gestation (term = 145 days). FTEE was performed by imaging the fetal heart in horizontal planes utilizing a 10-F, 10-MHz intravascular ultrasound catheter. CMTFE was carried out using a 5.0-MHz phased-array transducer replicating the FTEE imaging planes. We found close agreement between FTEE and CMTFE measurements of great vessel and cardiac valvar dimensions. Conversely, the variability between both techniques for measuring ventricular dimensions was inadequate. We conclude that FTEE permits measurement of great vessel and cardiac valve dimensions with high agreement with CMTFE measurements. This finding strengthens the applicability of FTEE as a monitoring tool during experimental open or fetoscopic fetal cardiac interventions.

Animals↗
PubMed1999

Minimally-invasive versus conventional aortic valve replacement--perioperative course and mid-term results.

OBJECTIVE: We performed a case-control-study to compare perioperative and mid-term results of minimally invasive with conventional aortic valve replacement. METHODS: Between 8/96 and 7/97, 113 patients underwent isolated aortic valve replacement (minimally invasive: 29, conventional: 84) in our Department. Diagnosis, ejection fraction, pressure gradient/regurgitation fraction, age, gender and body-mass-index were used as matching criteria for the case-control-study. For qualitative data correspondence was requested, for quantitative data deviations up to 10% were accepted. With these criteria 25 patients of the minimally invasive group were matched to 25 patients of conventional group. All patients were reexplored 1 year after aortic valve replacement. Statistical analysis was done by the Fisher's exact test for qualitative data and the Mann-Whitney test for quantitative data. RESULTS: We implanted 15 (20) bioprosthesis' and 10 (five) mechanical prosthesis' in the minimally invasive, respectively, conventional group. There were no statistically significant differences between both groups with respect to the perioperative course, only duration of surgery (mean 201.6 vs. 143.9 min, P < 0.01) and extracorporeal circulation (mean 116.1 vs. 71.3 min, P < 0.01) as well as aortic-cross-clamp-time (mean 77.9 vs. 46.9 min, P < 0.01) were significantly longer in the minimally invasive group. Postoperative complications occurred in one patient of the minimally invasive group (dissection of the right coronary artery) and four patients of the conventional group (third degree AV block, pneumothorax, grand mal convulsion, cardiopulmonary resuscitation). Two patients, one of each group, died during follow-up for unknown reasons. Follow-up revealed no significant differences with respect to clinical and echocardiographic data, but the shorter skin incision was cosmetically more accepted by patients of the minimally invasive group. Minor paravalvular leaks occurred in four patients of the minimally invasive and three patients of the conventional group as diagnosed by transthoracic echocardiography. CONCLUSIONS: Both surgical techniques may be performed with comparable perioperative and mid-term results, but the better cosmetic result in the minimally invasive group is paid by a longer duration of surgery.

Adult↗
PubMed1999

A simple new model of physiologically working heterotopic rat heart transplantation provides hemodynamic performance equivalent to that of an orthotopic heart.

BACKGROUND: The widely used non-volume-loaded abdominal heterotopic heart transplant (NL) in rats undergoes atrophy after transplantation. Various techniques have been designed to load the transplanted heart because of its potential immunological impact. Our aim was to create a volume-loaded heterotopic heart transplantation model (VL) capable of ejection and practical for routine studies. Using this model, we tested the hypothesis that VL isografts would retain myocardial performance comparable to native hearts (NH). METHODS: Heterotopic hearts were transplanted using and end-to-side anastomosis between the donor's superior vena cava and the recipient's abdominal inferior vena cava. The right ventricle loads the left ventricle (LV) via a direct anastomosis of the pulmonary artery to the left atrium. The LV ejects volume through an end-to-side anastomosis of the donor's aorta to the recipient's abdominal aorta. Hemodynamic data (systolic and diastolic LV pressures, dP/dt max and min, tau) were studied in-situ (at baseline and after adding volume) and in a Langendorff perfusion system (at baseline and after stimulation with isoproterenol) 2 weeks after transplantation. RESULTS: In situ systolic pressure and diastolic function of VL was superior to NL, and beta-adrenergic stimulated performance in the Langendorff perfusion of VL showed hemodynamic performance equivalent to NH, unlike NL which had a diminished response. CONCLUSION: This technique results in a volume-loaded ejecting heart transplant model that preserves anatomical structures. The VL can be evaluated in situ and after explantation in Langendorff perfusion system and may offer advantages if workload of the graft is of significance to the study performed.

Abdomen↗