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Biomedical subjects

E Wolner

Publications and source records attributed to E Wolner.

At least 325 records · Page 18Linked to original sources
PubMed1989

Blood platelets in cardiopulmonary bypass operations. Recovery occurs after initial stimulation, rather than continual activation.

The ultrastructure of blood platelets was related to platelet function and secretion products before, during, and after cardiopulmonary bypass. Circulating platelets from 15 patients undergoing aorta-coronary bypass operations were investigated at ten predetermined points of time by scanning and transmission electron microscopy. Simultaneously, platelet adenosine triphosphate, diphosphate, and serotonin, as well as plasma levels of platelet factor 4, beta-thromboglobulin, serotonin, thromboxane B2, lactic dehydrogenase, and free hemoglobin were measured. Moreover, platelet responsiveness toward adenosine diphosphate and collagen was determined by optical aggregometry. By scanning electron microscopy, the number of unactivated platelets dropped from 96% +/- 4% to 54% +/- 19% (p less than 0.05) 8 minutes after the onset of bypass. Simultaneously, the percentage of "shape changed" platelets significantly increased. No major release reaction was detected at this time. After the initial activation, platelet morphology began to recover although the bypass continued. During the late period of bypass, a highly significant correlation between increasing plasma levels of alpha-granule compounds (platelet factor 4 and beta-thromboglobulin) and lysis parameters (lactic dehydrogenase and free hemoglobin) was found. However, transmission electron microscopic analysis of the arterial filter and scanning electron microscopic findings of circulating platelets indicated that the release products in plasma were due not only to platelet lysis but also to a limited extent to secondary aggregation. In an inverse and probably causative manner, platelet morphology recovered, whereas the sensitivity of platelets to adenosine diphosphate and collagen decreased toward the end of bypass.

Adenosine Triphosphate↗
PubMed1988

[Clinical use of the artificial heart, indications and results].

Clinical experience with the artificial heart now comprises 520 cases. 390 patients had to be supported mechanically when they could not be weaned off cardiopulmonary bypass. 177 (45%) subsequently had their assist devices removed and 100 (25.4%) were discharged. Good functional results were achieved, since 30 of 36 long-term survivors are in NYHA class I or II. 140 underwent two-stage cardiac transplantation. Of 63 patients implanted with a ventricular assist device (VAD) 71% were transplanted and 51% survived. A total artificial heart (TAH) was used in 77 cases, 81% were transplanted and 47% survived. Five patients received TAH implantations as a permanent replacement of the failing heart. Though the clinical courses were complicated by strokes and infections and the patients were tethered to bulky drive units, it was proven that the TAH may sustain human life for up to 622 days, much longer than so far achieved in animal experiments. Improvements of the atrial connectors and valve holding components and of the biocompatibility of the blood contacting surfaces should overcome the complication of thromboembolism. Fully implantable devices which are currently being developed will avoid the problem of drive-line infections and provide fuller mobility to the patient.

Assisted Circulation↗
PubMed1988

[Treatment of ventricular tachyarrhythmias with an implantable cardioverter-defibrillator system].

5 patients (3 with coronary artery disease and chronic myocardial infarction, 2 with dilatative cardiomyopathy) with a mean age of 59 years (range 54-69 years) with drug refractory ventricular tachycardia and/or ventricular fibrillation received the automatic implantable cardioverter defibrillator (AICD). Intraoperative testing revealed a mean defibrillation threshold of 13 +/- 2.7 Joule. Over a mean follow-up period of 15.2 months (range 3-25 months) the patients received a total of 117 discharges. 15% of the delivered shocks were recorded during continuous ECG monitoring, 13% were associated with palpitations and 27% were discharged during syncope. 45% of shocks occurred in the absence of symptoms. No patient died suddenly. 1 patient died of intractable heart failure, 1 patient died of septic shock. In carefully selected patients the automatic implantable cardioverter defibrillator is an effective tool in the treatment of life-threatening ventricular tachyarrhythmias. Modifications of the device to incorporate programmability of the cut-off rate, the sensing criteria and the levels of shock energy, as well as the options for different pacing modes combined with memory functions are needed to improve antiarrhythmic strategies.

Aged↗
PubMed1988

Two level entry concept for analog digital conversion package: usage as blackbox or toolkit.

Analog/Digital conversion of up to 16 channels can be set up and executed interactively with sampling rates individually adjusted for each channel. Additionally, asynchron and parallel digital I/0 is provided, including the possibility of triggering the beginning and the end of data acquisition on an external TTL signal. For non-experienced personnel the package can be run fully interactively with help-menus. Conversely, the experienced user can skip the menu level and directly access the A/D conversion card at the programmers' level in FORTRAN, BASIC or PASCAL. This two level approach considerably enhances the versatility of the package. Data structures in memory and on disk are the same for both levels. Thus, data acquired in menu mode can be compatibly accessed and evaluated from the menu--as well as the programmers' level. Furthermore, a concept is presented for a most efficient and convenient transfer of pre-processed data onto an IBM-mainframe for further analysis in SAS. This transfer scheme allows for continued transparency of the data files, should--for technical reasons or due to changes in the type of data acquired--changes or upgradings of the A/D conversion software become necessary. The package is available for IBM-XT/AT personal computers.

Analog-Digital Conversion↗
PubMed1988

Results and prognostic factors after resection of pulmonary metastases.

One hundred and fifty-nine thoracotomies were performed in 122 patients with pulmonary metastases. The patients' ages ranged from 2 to 76 years, and 13 patients were younger than 18 years. The primary tumour was carcinoma in 83 cases, sarcoma in 29 cases and melanoma in 10 cases. The primary tumour in children was osteogenic sarcoma (6 patients), Ewing's sarcoma (2 patients) and Wilms' tumour (2 patients). With a minimum follow-up of 2 years, an actuarial 5-year survival rate of 38% was observed for carcinoma and 28% for sarcoma. Four of the children survived disease-free for 3 years or more after pulmonary metastasectomy. The primary tumour in these cases was osteogenic sarcoma and Ewing's sarcoma. A statistically significant difference in survival was found between the groups of carcinoma and sarcoma, but the prognosis for melanoma patients was markedly worse. In carcinoma patients the main prognostic factor was the duration of the disease-free interval. The actuarial postthoracotomy survival in patients with osteogenic sarcomas was 31% at 5 years, and 18% at 5 years in soft-tissue sarcomas. The size of the lesions, activity and disease-free interval correlated with survival in the osteogenic sarcoma group, and the number of lesions in the soft-tissue sarcoma group. An aggressive surgical approach towards pulmonary metastatic disease thus appears to be justified.

Adolescent↗
PubMed1988

Results of orthotopic heart transplantation with and without the use of maintenance steroids.

From March 1984 to June 1987, 51 patients underwent primary orthotopic heart transplantation at the Second University Department of Surgery, Vienna. Recipients were immunosuppressed with a combination of either ciclosporine and azathioprin (double drug regimen = DD, 10 patients), or ciclosporine, azathioprin and low-dose steroids (triple drug regimen = TD, 33 patients). Four patients who died intra- or perioperatively and 4 who were switched to conventional therapy were excluded from analysis. In both groups, ciclosporine was administered to obtain whole blood HPLC trough levels of 200-400 ng/ml in the 1st month, 150-250 ng/ml from the 2nd to the 6th and 100-150 ng/ml after the 6th month. Azathioprin 2 mg/kg per day was given, and in TD patients, an additional 0.2 mg/kg per day of prednisolon: all patients received prophylactic antithymocyte globulin for 7-10 days postoperatively. Five deaths from acute rejection in the DD group contrasted with none in the TD group. The high incidence of fatal rejection episodes was reflected in a 40% Kaplan-Meier 1-year survival for DD vs 84% for TD (p less than 0.0001). Analysis of endomyocardial biopsies (DD vs TD) demonstrated 20.4% vs 57.0% absent, 46.0% vs 29.5% mild, 31.2% vs 12.4% moderate and 2.4% vs 1.1% severe rejection. Fatal and nonfatal infections and toxic side effects occurred with the same frequency in both protocols. Calculation of mean ciclosporine levels resulted in 249.7 ng/ml (TD) and 206.0 ng/ml (DD) in the 1st month (p less than 0.05). Consequently, adjunctive maintenance low-dose steroids combined with increased ciclosporine levels in the early posttransplant course are considered responsible for the improved results.

Azathioprine↗
PubMed1988

Incidence and severity of acute cardiac allograft rejection with two different low-dose cyclosporine maintenance protocols.

Currently cyclosporine (CyA) represents the main immunosuppressive agent used after cardiac transplantation and usually is administered in combination with prednisone and/or azathioprine for prevention of graft rejection. From March, 1984, to August, 1987, 53 patients underwent orthotopic heart transplantation for terminal-stage heart disease at the Second Department of Surgery, University of Vienna. All patients received CyA in increasing dosage (3 mg/kg to 6-10 mg/kg) postoperatively according to renal function, obtaining a trough high-pressure liquid chromatographic whole-blood target level of 200 to 400 ng/ml at the end of the first week. CyA was subsequently tapered to 100 to 150 ng/ml after 6 months. From March, 1984, through April, 1986, maintenance immunosuppression was carried out with a double-drug regimen of CyA and azathioprine. Since May, 1986, a triple-drug schedule was applied with CyA, azathioprine, and prednisone. Under triple-drug therapy, the incidence of mild, moderate (p less than 0.0001), and severe (p = 0.05) allograft rejection proven by endomyocardial biopsy decreased significantly with a corresponding increase of absent (p less than 0.0001) rejection. Freedom from moderate, severe, and lethal graft rejection, number of rejection episodes per patient after 1 year (double drug, 1.0, versus triple drug, 2.5), and patient survival disclosed significant improvement for recipients of the triple-drug regimen. Both groups had the same incidence of infectious complications; freedom from death by infection after 1 year was 90% versus 91% (double versus triple drug, p = 0.20).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1988

Topographic brain mapping of EEG before and after open-heart surgery.

The brain function of 60 patients undergoing open-heart surgery (36 patients receiving coronary artery bypass, 21 patients valve replacements, 3 both) was investigated before and 10 days after the operation utilizing topographic brain mapping of the electroencephalogram (EEG). The postoperative EEG changes were characterized by a slight delta-theta increase, an alpha decrease [especially in the fast alpha (10.5-13 Hz) band] and a beta increase in the relative power. The total power and the absolute power of the delta-theta, alpha and beta showed a decrease, the dominant frequency a significant slowing from 9.7 to 9.3 Hz. The centroid of alpha and beta activity decreased as well. These results are similar to findings obtained in patients with organic brain syndrome. The EEG changes were prominent over the left hemisphere, which may be of particular clinical relevance.

Adult↗
PubMed1988

Excimer laser-induced simultaneous ablation and spectral identification of normal and atherosclerotic arterial tissue layers.

A krypton-fluorine excimer laser at a 248-nm wavelength was used to irradiate normal and severely atherosclerotic segments of human postmortem femoral arteries. Single pulses and multiple pulses required for penetration or perforation of the arterial wall were applied with 16 nsec pulse width and 5 J/cm2/pulse energy fluence. The total fluorescence of irradiated and ablated tissue was analyzed in real-time mode by means of spectroscopy. Each laser pulse produced one spectrum that was characteristic of the composition of the tissue layer, which was ablated. Fluorescence spectroscopy indicated a broad-continuum emission between 300 and 700 nm with peak fluorescence of equal intensity at wavelengths of 370 and 460 nm (ratio, 1.004 +/- 0.087) for normal media layers. Atheromas without calcification (lipid, fibrous, and mixed) were found with spectral maxima at the same wavelengths but with significantly reduced intensity at 460 nm (ratio, 1.765 +/- 0.263; p less than 0.001). In contrast to this broad-continuum fluorescence, calcified plaques displayed multiple-line emission with the most prominent peaks at wavelengths of 397, 442, 450, 461, 528, and 558 nm. These fluorescence criteria identified the histologically classified target tissue precisely. Histological examination of the corresponding arterial layers indicated sharply delineated and circumscribed tissue ablation. These results indicate that simultaneous tissue identification (diagnosis) and ablation (treatment) by excimer laser irradiation is feasible under strict laboratory conditions. We conclude that this principle demonstrates the potential for laser beam control by means of target-specific ablation.

Angioplasty, Balloon↗
PubMed1988

[Current status of use of the artificial heart in combination with heart transplantation].

Acute and therapeutically uncontrollable cardiac insufficiency in a case of chronic heart disease with acute risk of rejection and with a record of previous transplantation or during a heart operation should be considered as an indication for implantation of an artificial heart or a ventricle-supporting system, if a donor heart is not available. Two results are expected from such an approach, restoration of adequate circulation and improvement of organ functionally providing a chance for later transplantation. Attention should be given, according to the authors' own experience, to effective surgical haemostasis. Infections have quite often proved to be incurable after implantation of an artificial heart and, consequently, provide a clear-cut contraindication to implantation.

Assisted Circulation↗
PubMed1988

[General surgical interventions in heart surgery patients].

Due to the rapid development in cardiac surgery it is obvious that we now find more patients after heart operations requiring major noncardiac surgery. Knowledge concerning the special problems in treatment of patients with prior cardiac surgery is indispensable to guarantee a low perioperative risk. It is of great consequence, what kind of cardiac disease we are dealing with, whether the cardiac defect could be corrected partially or totally and how the cardiac index has been finally. We discuss the situation after different cardiac operations including coronary bypass grafting, heart valve surgery and heart transplantation. Several multi-case studies could prove that after successfully performed bypass grafting a coronary heart disease does not improve the perioperative risk of following surgical treatment. Some authors recommend a 6 month interval after coronary heart surgery. A higher risk for ventricular arrhythmias can be found in patients with a manifest coronary heart disease following operative revascularisation. Special comment is given to the recommended treatment of the different stages of coronary heart disease in respect to the time course with noncardiac surgery. General surgery after heart valve replacement can be complicated by the appearance of dysrhythmia and arrhythmia, left heart failure, tendency to bleed and higher risk of infections. Patients with a transplanted heart need special care on the part of narcosis and asepsis.

Heart Diseases↗
PubMed1987

[Orthotopic heart transplantation--experiences at the University Surgical Clinic II in Vienna (status: June 1986)].

Since 1984 27 heart transplantations (HTX) were carried out in 25 patients at the 2nd Department of Surgery, University of Vienna. The classic orthotopic technique of Lower and Shumway was used in all cases. Routine immunosuppression consisted of azathioprine and cyclosporin-A. In order to treat the main complications successfully, i.e. rejection and infections, we were compelled to establish an extensive follow up regimen. The early recognition of acute rejection was based on the findings obtained by cutaneous as well as epicardial ECG leads, in conjunction with cytoimmunological monitoring on the basis of RIA measurements of the serum levels of Neopterin and gamma-Interferon. Furthermore, we recorded some parameters of ventricular performance, such as the isovolumetric relaxation time and the radiologically measured heart volume. An endomyocardial biopsy was carried out to secure the diagnosis. Pulsed doses of methylprednisolone were used for the treatment of rejection, facultatively combined with ATG in the absence of improvements. Infections were pinpointed by comprehensive serum tests and various blood, sputum and urine cultures. The management consisted of treatment with the requisite antibiotics. Of 25 primarily transplanted patients 15 patients are still alive. 5 persons, amongst them 2 children, have survived already for more than 1 year. 6 patients died at an early stage. In 3 cases the cause of death was intractable infection. In 1 case multi-organ failure occurred and 1 patient died due to acute organ failure. 4 patients died at a late stage and acute severe rejection was responsible in all these cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Implantation of the Duromedics bileaflet cardiac valve prosthesis in 400 patients.

From September, 1983, to April, 1986, 451 Duromedics bileaflet cardiac valve prostheses were implanted in 400 patients at our institution in Vienna. Aortic valve replacement was done in 190 patients, 157 underwent mitral valve replacement (1 patient also underwent tricuspid valve replacement), 52 underwent double valve replacement, and 1 patient underwent isolated reoperation for tricuspid valve replacement. Concomitant procedures were performed in 86 patients (21.5%). Sixty-one patients (15.2%) had undergone previous cardiac surgery; 32 (8%) had undergone earlier valve replacement. The early mortality rate (within 30 days) was 6.25% (25 patients). Follow-up was done on 337 surviving Austrian citizens; this represents 429 patient-years. The late mortality rate was 2.1% per patient-year (9 patients). We observed paravalvular leak in 3 patients (0.7% per patient-year), thromboembolism in 4 (0.9%), prosthetic valve endocarditis in 5 (1.2%), and anticoagulant-related hemorrhage in 10 (2.3%). Valve failure occurred in 8 patients (1.8%). We conclude, therefore, that good clinical results and a low complication rate can be achieved with this new type of valve.

Anticoagulants↗
PubMed1987

Cyclosporin-A induced heart failure after orthotopic heart transplantation.

Two patients suffering from dilated Cardiomyopathy (CMP) had to undergo orthotopic heart transplantation (HTX). In both cases, the postoperative period was without any complications. The immunosuppression consisted of Cyclosporin-A and Azathioprine including a one week prophylactic treatment with Antithymocyte Globuline (ATG). Four months postoperatively, they developed clinical signs of heart failure. The endomyocardial biopsies showed rejection at stage I according to Billingham's grading plus a fine interstitial fibrosis. Therefore, the Cyclosporin treatment was suspended and replaced by conventional immunosuppression consisting of Prednisolone and Azathioprine. Acute heart failure was managed by catecholamines in combination with aggressive diuretic therapy. After three weeks, both patients recovered. 12 weeks later, one died because of an acute rejection episode. The other is in good condition, with conventional immunosuppression at the present time. A vascular process caused by Cyclosporin-A as the pathogenic mechanism is considered. The absence of rejection signs in the biopsies as well as the remarkable improvement of heart failure after withdrawal of Cyclosporin-A support this possibility.

Coronary Disease↗