[Analysis of the ECG in diagnosis of graft rejection following heart transplantation].
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Electrocardiography↗
Biomedical subjects
G Laufer
Publications and source records attributed to G Laufer.
[Orthotopic heart transplantation at the 2d Surgical Department of the University of Vienna: 4-year experience].
Between March 1984 and August 1988, 89 orthotopic cardiac transplants were performed in 87 patients at the Second Department of Surgery, University of Vienna. 2 patients underwent retransplantation and 3 patients received previously a total artificial heart bridge. Recipients were immunosuppressed with low dose cyclosporine, azathioprine and since May 1986 with additional low dose prednisolone; all patients were supplemented perioperatively with either ATG or OKT3. 1-year survival rates continuously increased from 33% in 1984 to 88% in 1987 (p = 0.07). The one-year survival rate in recipients given double drug therapy (cyclosporine and azathioprine) was 43% as compared with 77% on triple therapy (cyclosporine, azathioprine and prednisolone, p = 0.003). Acute rejection was the leading cause of death. These data indicate that the substantial improvement in survival rates is attributable to augmented immunosuppression and to improved patient management and recipient selection.
Adolescent↗
[Development of a physiological pacing concept at the 2d Surgical Department of the University of Vienna].
With the transvenous approach of atrial leads in 1978 a progressive physiological pacing concept was developed at the Second Surgical Department of the University of Vienna. Using multiprogrammable fully-automatic double-chamber pacers and the technology of biological sensors, the most suitable treatment for any individual patient can be chosen. Our recommendations are DDD stimulation for complete AV block and rate-responsive pacing of the atrium or the ventricle for the Sick-Sinus-Syndrome or atrial fibrillation, respectively. Second choices for AV block are rate-responsive single-chamber pacemakers or simple programmable pacemakers generally.
Atrial Fibrillation↗
Characteristics of 308 nm excimer laser activated arterial tissue photoemission under ablative and non-ablative conditions.
The present study was designed to assess the characteristics of tissue photoemission obtained from normal and atherosclerotic segments of human postmortem femoral arteries by 308 nm excimer laser irradiation of 60 ns pulsewidth. Three ablative (20, 30, and 40 mJ/pulse) and three non-ablative (2.5, 5, and 10 mJ/pulse) energy fluences were employed. Both the activating laser pulses and the induced photoemission were guided simultaneously over one and the same 1,000 micron core optical fiber that was positioned in direct tissue contact perpendicular to the vascular surface. The spectral lineshape of normal arterial and noncalcified atherosclerotic structures was characterized by a broad-continuum, double-peak emission of relevant intensity between wavelengths of 360 and 500 nm, with the most prominent emission in the range of 400-415 (407 nm peak) and 430-445 nm (437 nm peak). Fibrous and lipid atherosclerotic lesions, however, exhibited a significantly reduced intensity at 437 nm compared to normal artery layers (P less than 0.001), expressed as a 407/437 nm ratio of 1.321 +/- 0.075 for fibrous and 1.392 +/- 0.104 for lipid lesions. Normal artery components presented with approximately equal intensity at both emission peaks (407/437 nm ratio: intima, 1.054 +/- 0.033; media, 1.024 +/- 0.019; adventitia, 0.976 +/- 0.021). Comparison of spectral lineshape obtained under various energy fluences within a group of noncalcified tissues disclosed no substantial difference using the 407/437 nm ratio (P greater than 0.05). In contrast, calcified lesions revealed high-intensity multiple-line (397, 442, 461, and 528 nm) emission spectra under ablative energy fluences, whereas a low-intensity broad-continuum, single-peak spectrum resulted from irradiation beyond the ablation threshold. Thus, these findings suggest fluorescence phenomena for broad-continuum spectra, and plasma emission for multiple-line spectra as an underlying photodynamic process. Regardless of the activating energy fluence, spectral analysis of 308 nm activated photoemission provides accurate information about the laser target under standardized in vitro conditions. It is demonstrated that direct contact ablation and simultaneous spectral imaging of the target tissue via the same optical fiber is feasible.(ABSTRACT TRUNCATED AT 400 WORDS)
Adult↗
[A transition zone phenomenon of the skin in cadavers lying in bath water].
In three cases a phenomenon is reported, seen on the skin of bodies found dead after a longer time of lying in bathtubs filled with water. The sign was parallel to the surface of the water and showed a breadth up to about 1 cm. Contrary to the surrounding skin, the mark was characterized by paleness and clearly les distinct formation of postmortem alterations as put-refaction. Searching for an explanation, temperature measurements were performed in model. The results showed the marginal paleness of the skin to be a thermal phase transition phenomenon. This mark has a forensic message too: it demonstrates a longer remaining of the corpse in the corresponding position, is a statement concerning the high of the water level, and allows a reconstruction of the original situation after manipulation, but is no sign of vital reaction.
Adult↗
Experimental photoablation of meniscus cartilage by excimer laser energy. A new aspect in meniscus surgery.
Excimer lasers have been demonstrated to provide a very precise and circumscribed ablation of synthetic polymers and biological tissues. We investigated in vitro the use of ultrashort pulsed ultraviolet excimer-laser energy for controlled removal of meniscus cartilage under the aspects of arthroscopic meniscectomy. A krypton-fluorine gas mixture was used to achieve laser emission of 248-nm wavelength. A total of 22 human menisci obtained either by operation or necropsy were irradiated over a range of energy fluence (2.15-3.07 J/cm2/pulse), repetition rates (5-20 Hz), and exposure time (15-60s). Ablation rates of 4.00-5.76 microns per pulse were obtained. Light-microscopic examinations demonstrated tissue ablation without any evidence of pathological changes associated with continuous-wave laser irradiation. Effects of laser energy were clearly limited to the target of the laser beam, and tissue removal proceeded without production of heat or smoke. Due to the lack of pathological alterations observed, excimer-laser irradiation of meniscus cartilage may prove to be advantageous for precisely cutting and removing menisci without injury to the surrounding normal tissue. Clinical application of excimer-laser irradiation includes the development of suitable fiberoptics and laser coupling, as well as modification of fiber tips.
Humans↗
[A modified laser system for laser angioplasty using a sapphire tip].
This study deals with 26 patients on whom successful laser angioplasty of peripheral vascular occlusions had been carried out, using an Nd-YAG high energy laser system (100 watts) with a sapphire point. The technical requirements are presented and the primary success and complication rates in our material are discussed.
Angioplasty, Balloon↗
Human endothelial cell seeding: evaluation of its effectiveness by platelet parameters after one year.
Platelet parameters were assessed in patients after implantation of polytetrafluoroethylene (PTFE) grafts, either nonseeded or seeded with autologous endothelial cells or reversed saphenous vein grafts, during the follow-up period of 1 year. The objective of this investigation was to compare the sensitivity of different noninvasive platelet parameters with the assessment of the result of endothelial cell seeding. Scanning electron microscopic investigation of circulating blood platelets showed a significantly higher incidence of activated platelets in patients with seeded or nonseeded PTFE grafts, compared with patients after reversed vein graft implantation. "Shape-changed" platelets, as well as membrane-perforated thrombocytes, were found exclusively in the circulating blood of patients after seeded or nonseeded PTFE graft implantation, indicative of platelet trauma by the artificial graft surface. Plasma levels of platelet factor IV and beta-thromboglobulin, as well as the uptake of indium-111-labeled platelets, failed to show statistically significant differences after 1 year of follow-up. The similar results for seeded and nonseeded grafts indicate the failure of endothelial cell seeding to induce the development of a nontraumatizing surface, comparable to that of saphenous vein grafts.
Blood Platelets↗
Comparison of a monoclonal anti-T cell antibody vs ATG as prophylaxis after heart transplantation.
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Adolescent↗
Laser angioplasty in the treatment of peripheral vascular disease.
Compared with percutaneous transluminal angioplasty (PTA), the ablation of atherosclerotic tissue by laser energy promises advantages in the treatment of atherosclerotic vascular disease in the peripheral arteries. In the last few years, the basic clinical feasibility has been demonstrated. By development of different lasers and light transmitting devices even the safety of laser energy applied intraluminally has been improved, but to date, no gold standard of laser angioplasty has been defined. Many technological hurdles are still to be overcome and some specific laser-associated problems, especially the high incidence of perforations, has to be resolved before routine application is possible. The future of lasers in vascular diseases seems promising, but there is still a long way to go before reaching maturation.
Angioplasty, Balloon↗
Independent risk factors predicting acute graft rejection in cardiac transplant recipients treated by triple drug immunosuppression.
To assess independent risk factors predicting the occurrence of clinically significant acute rejection episodes in the first 6 months after cardiac transplantation, we performed a multivariate stepwise logistic regression analysis. Forty-three recipients, undergoing transplantation between September 1986 and May 1988, were eligible for analysis and received standardized, low-dose triple drug maintenance immunosuppression with cyclosporine, azathioprine, and prednisolone. Immunoprophylaxis was supplemented perioperatively with either a polyclonal (antithymocyte globulin, N = 26) or a monoclonal (OKT3, N = 17) anti-T-cell antibody. Investigated, conceivable risk factors comprised recipient and donor age, ischemic time, perioperative anti-T-cell antibody prophylaxis, recipient preoperative status, underlying disease, previous cardiac operation, and histocompatibility parameter (mismatches for HLA-A, HLA-B, HLA-DR, HLA-B+DR, HLA-A+B+DR, and Rh0[D] antigen, HLA-DRw6 positive recipient, and identify for ABO system). Univariate analysis suggested significant influence of the type of antibody used perioperatively (p = 0.0024) and the number of mismatches for HLA-A+B+DR (p = 0.0037) and for HLA-B+DR (p = 0.0043). Stepwise logistic regression yielded the number of mismatches for HLA-B+DR (p = 0.0029) and the type of antibody used perioperatively (p = 0.0031) as being highly significant predictors of acute cardiac rejection. Six-month freedom from rejection was 100%, 41%, and 27% for recipients with two, three, and four mismatches for HLA-B+DR and 59% versus 22% for recipients with polyclonal versus monoclonal antibody prophylaxis. Similar to results with kidney transplantation, these results indicate that a poor donor/recipient match for combined HLA-B+DR loci constitutes an independent risk factor for acute graft rejection in low-dose triple drug immunosuppressed cardiac recipients, which stimulates the potential concept of prospective HLA matching. In our experience OKT3 prophylaxis provides significantly less effective prevention of acute rejection than a comparable course of antithymocyte globulin.
Acute Disease↗
Infectious complications in heart transplant recipients with combined low dose cyclosporine, azathioprine and prednisolone (triple drug) immunosuppression.
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Azathioprine↗
[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↗
Percutaneous transluminal excimer laser angioplasty in total peripheral artery occlusion in man.
Laser angioplasty and laser-assisted angioplasty have become a clinical reality. Producing sharply defined borders of the ablated area with minimal adjacent thermal damage, excimer lasers offer several proven and some potential advantages over conventional systems. To evaluate the feasibility of excimer laser angioplasty, we have treated one patient using 308-nm radiation via a bare fiber in direct contact with the total occlusion of a right femoral artery. The lesion was successfully recanalized, thus allowing easy passage of the balloon catheter and subsequent dilatation. This percutaneous laser recanalization of an occluded peripheral artery is one of the first to be done in man using excimer laser radiation, thus demonstrating that the technique is feasible and the system is potentially useful.
Angioplasty, Balloon↗
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↗
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↗
Comparative study of different laser systems with special regard to angioplasty.
Laser angioplasty has found increasing interest in the treatment of cardiovascular diseases. First clinical applications of laser angioplasty in atherosclerotic stenoses or occlusions of peripheral and coronary vessels primarily showed a high success rate, but later were followed by significant complications as aneurysm formation, late perforations and restenoses. Most of these complications were due to a thermal damage of surrounding wall structures. To avoid these complications an ideal laser system should only minimally influence surrounding tissue layers and should offer a well predictable penetration and ablation including also severely calcified material. In conventional continuous wave laser systems photo energy is mainly changed into thermal energy. Mode of application, local cooling and the use of special laser probes can reduce the thermal side effects, but nevertheless histologic examinations revealed thermal injuries of various degree to surrounding structures. Furthermore these laser systems mostly faile to ablate or penetrate calcified plaques and only pulsed Nd:YAG-lasers with high frequencies seem ot offer some improvement. Eximer lasers with their wave lengths of 193, 248 and 308 nanometers also work in a high frequent pulsed mode. They offer a very low penetration and mainly show a so called photoablative effect with only minimal thermal side effects. Within a distance of only 50 micrometers temperature raises in the surrounding tissue up to 5 degrees C and in a distance of 1 mm, up to 1.5 degrees C. Eximer lasers are moreover able to penetrate calcified material. A transluminal application is up till now limited by a lack of flexible fiber systems, which can deliver the high energy pulses. Another point of discussion are the mutagenity and cancerogenity of ultraviolet light.(ABSTRACT TRUNCATED AT 250 WORDS)
Angioplasty, Balloon↗
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↗