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Biomedical subjects

E Wolner

Publications and source records attributed to E Wolner.

At least 343 records · Page 19Linked to original sources
PubMed1987

Total artificial heart bridging: a temporary support for deteriorating heart transplantation-candidates--methods and results.

Since 1975 at the 2. Dept. of Surgery, University of Vienna, Austria, artificial circulation devices and artificial hearts have been constructed and in experimental use. We started a clinical heart transplantation (HTX) program in 1984, and up to now more than 40 HTXs have been performed. Since May 1986, 3 patients--all suffering from end stage dilatative cardiomyopathy--received total artificial heart (TAH) as a temporary support until HTX was possible. Two of them were transplanted after 9 and 10 days. The third patient, who additionally suffered from a postinfarctial lung abscess and had to undergo an indispensable lobectomy contemporary with TAH implantation, could not be transplanted due to an incurable infection, which he died of after 22 days on TAH. The temporary TAH implantation proved to be a valuable measure preventing life-threatening circulatory deterioration. After restoration of a sufficient circulation by the implanted system, the patients' general conditions improved and the concomitant dysfunctions of kidneys, brain, and other vital organs, due to cardiogenic shock, could be rectified in those two patients, who underwent transplantation. Thromboembolic complications were observed only in the third patient, who developed a small infarction in the anterior lobe of the left hemisphere caused by cerebral embolism after 3 weeks of TAH pumping. The use of TAH is liable to severe, even lethal, complications. At present it should be used only as a last resort. If a donor heart is not available, this measure can be a real chance to save the patient's life.

Adult↗
PubMed1987

Implantation of the left ventricular assist device.

Development of mechanical devices for support of the failing heart is a major goal in cardiac surgery. The application of left ventricular assist device (LVAD) is a promising approach in the case of severe and otherwise untreatable cardiac failure. In our experience we have used two external centrifugal pumps for the extracorporeal biventricular cardiac support in a post-transplantation patient who experienced severe rejection six months after heart transplantation. Our own series includes a total of ten implantations of LVAD's with six patients who could be weaned from the device but only one long-term survivor. The clinical results are not encouraging which suggests that the heart of the patient who needs an LVAD has been damaged beyond any chance for later recovery. Obviously timing is the most crucial aspect of the decision to implant the device. It would appear that orthotopic implantation of the transplanted heart remains the method of definitive treatment.

Cardiac Surgical Procedures↗
PubMed1987

Plaque ablation by excimer laser irradiation using a movable energy-transmitting device.

During the past 2 years, excimer laser energy has been shown to provide a highly suitable type of atherosclerotic plaque ablation, especially in small-diameter vessels such as coronary or crural arteries. Nevertheless, transmission of far-ultraviolet pulsed laser power has remained a major problem in animal studies and clinical trials. In an attempt to solve this problem, we constructed an energy-transmitting device for use with a Lambdaphysics EMG 102 excimer laser. The transmission system, which was housed in a rigid articulated arm, allowed movement in all directions and rotation along the long axis, thus permitting easy handling and guiding of the laser beam in the operating field. To test whether this device could deliver enough energy to remove atherosclerotic plaques within a period that would meet the requirements for intraoperative use, we obtained fresh human cadaver coronary arteries both with and without atherosclerotic disease, and irradiated them vertically and coaxially. A power meter was used to determine the effective amount of energy delivered at the distal end of each vessel. Energy densities up to 3 J/cm(2)/pulse were obtained, owing to energy focussing within the transmitting device. At 5 Hertz (Hz), tissue ablation consisted of approximately 20 microm/pulse. Areas of normal vascular tissue, as well as fibrohyalinous and lipid plaque components, were promptly ablated. Macroscopically, the "lasered holes" appeared well-circumscribed, with clear-cut surfaces and no carbonization. Light microscopy revealed no thermal damage to the boundary tissue. With this new energy-transmitting device, the surgeon can use excimer laser irradiation intraoperatively. There is no significant loss of energy between the generator and the tip, and energy densities of 3 J/cm(2)/pulse are available for sufficient plaque removal.

Journal Article↗
PubMed1987

Circumferential tracheal replacement with costal cartilage.

Long-term incorporation of foreign material or tissue in circumferential tracheal replacement will lead to progressive growth of granulation tissue, provoking either airway stenosis or a reduction of subepithelial blood supply and thereby preventing the appearance of functioning ciliated epithelium in the replaced segment. In experience with dogs, a 5 cm length of the thoracic trachea was replaced circumferentially with fresh autogenous untreated circularly positioned cartilage-perichrondrium strips. During the period of strengthening of this neotracheal wall, a temporary tracheal prosthesis made of tubular silicone rubber with absorbable sewing rings of polyglactin 910 placed 3 mm from the end of the tube served as a tracheal replacement. Six months after the cartilage transplantation, the neotracheal wall had stabilized sufficiently for the silicone rubber tube to be extracted with an endoscope. Four weeks after extraction of the silicone rubber tube the neotracheal segment was completely covered with ciliated epithelium over a thin subepithelial, well-vascularized layer. Subepithelial vessels had a diameter of 180 microm. They were a continuation of the intercartilaginous main vessels of the neotracheal wall. The presence of normal cilia on the epithelium was proved through transmission electron microscopy. Even the tubules of the cilia were arranged in the right order. In the ink test, movement of the transport marker across the neotracheal segment at a speed of 18 to 21 mm/min was proof of mucociliary clearance. In a process of migration starting from the margin of the trachea, the ciliated epithelium pervaded and replaced the preexisting temporary one-layer stratified squamous epithelium. This completely new technique of circumferential tracheal replacement with autogenous cartilage, avoiding permanent incorporation of foreign material, succeeds within the observation period of up to 7 months.

Animals↗
PubMed1987

[Prognostic factors in cardia cancer].

Among 164 patients operated upon for adenocarcinoma of the cardia 102 (61%) were resected, 87 of them with curative intent. The mortality within 30 days was 20%, and the 5-year survival 15%. A total gastrectomy was performed in 36 patients, whereas a proximal partial gastrectomy was carried out in 66 cases. The median survival was 19 months after total gastrectomy, and 11 months after proximal resection (Breslow: 0.22). Only in stages N0 and N1 total gastrectomy resulted in a significantly longer (32 months) median survival than proximal resection (11 months; p = 0.03). The impact of total gastrectomy was more pronounced in the diffuse type according to Lauren, whereas lymphadenectomy was more effective in stages N0 and N1 and in Lauren's intestinal type. It is concluded that total gastrectomy should be carried out in all cases of carcinoma of the cardia.

Adenocarcinoma↗
PubMed1987

[Risk factors for morbidity and mortality in resection of cancer of the cardia].

Operations were performed on 166 patients for adenocarcinoma of the cardia, between 1970 and 1986, with resections being applied to 102 of them (6.1 per cent), including 87 curative approaches with complete removal of tumours and no macroscopic evidence of metastases. Total gastrectomy with oesophagectomy was performed on 36 patients and proximal oesophagogastrectomy on 66, in 43 of these via left thoracic incision. Regional lymph nodes were free of tumour in 29 patients (28 per cent). The other approaches to proximal resection were thoracoabdominal in eight cases, abdominal in 13, and transmediastinal in two. Leakage of oesophageal anastomosis occurred in 19 cases and was followed by septicaemia and death in 13. Overall mortality during hospitalisation amounted to 22.5 per cent, including two patients who died on the 30th postoperative day as a result of dehiscence and septicaemia. Mortality figures were 17 per cent following total gastrectomy and 19 per cent in the wake of proximal gastrectomy by thoracic incision. Mortality amounted to 48 per cent in the 23 cases on which abdominal, thoraco-abdominal, and transmediastinal operations had been performed. Multiple logistic regression was used to determine age, ECG, spread of lymph nodes, and surgical techniques as potential risk factors. Emphasis in the context of surgical techniques was laid on proximal versus total gastrectomy, incision on both sides of the diaphragm, palliative resection, and anastomotic suturing (using one-layer or two-layer techniques or mechanical staples). Tumour spread to lymph nodes and proximal resection were the only independent variables associated with dehiscence. Electrocardiogram (ECG), lymph node involvement, and palliative resection proved to be of relevance to prognostication of lethality. No statistical correlations were found to exist between lethality, on the one hand, and surgical approach, age of patient, incision on either side of the diaphragm or suturing, on the other. The conclusion was drawn that in cases of cardia carcinoma total gastrectomy does not aggravate the risk of lethality, as compared to cardia resection.

Adenocarcinoma↗
PubMed1986

Analysis of coronary-sinus-occlusion pressure by iterating the convolution integral.

Intermittent coronary sinus occlusion (ICSO) has been shown to reduce infarct size and to improve regional myocardial function. Since the efficiency of the procedure is closely related to proper intervals of occlusion and release of the coronary sinus, the reactions of coronary haemodynamics to this intervention have to be investigated. Coronary sinus pressure measurements obtained from anaesthetized dogs are analysed for three different conditions: normal coronary perfusion, experimentally induced infarction of the LAD performed according to a specific time pattern. The mathematical modelling of the coronary sinus pressure (CSP) reaction upon ICSO is accomplished by a convolution integral, incorporating a memory function g(x). With the aid of a numerical technique this function is evaluated to reproduce the measured data as closely as possible. Since g(x) describes the CSP response in a universal manner it can serve subsequently to predict reactions to different occlusion and release patterns not actually measured. This use of a mathematical model may provide economical paths for future investigations by avoiding prohibitively large numbers of animal studies. For different physiological states; normal perfusion, infarction and reperfusion; we obtained different memory functions. These differences in g(x) are then shown to be precisely related to known characteristics of the normal and diseased state of the myocardium. Understanding the link between cardiovascular physiology and its mathematical representation is seen as an important aid in the selection of therapeutic interventions.

Animals↗
PubMed1986

Early prediction of deep sternal wound infection after heart operations by alpha-1 acid glycoprotein and C-reactive protein measurements.

Serum C-reactive protein (CRP) and alpha 1-acid glycoprotein (AAG) levels were studied in 188 patients undergoing heart operations with cardiopulmonary bypass. Mediastinitis or osteomyelitis of the sternum or both developed in 10 patients on postoperative day 4 to 13 (median, day 9). The mean CRP levels on day 2 were lower in patients with later deep sternal wound infection (9.1 +/- 1.5 mg/dl [mean +/- standard error]) compared with patients without major infections (14.0 +/- 0.8 mg/dl; p = 0.103 [univariate logistic regression]). AAG levels on day 2 reacted in a similar manner, yielding 78.2 +/- 5.5 mg/dl and 100.9 +/- 2.7 mg/dl, respectively (p = 0.0004). No correlation was found between CRP or AAG and duration of cardiopulmonary bypass, number of blood transfusions, or total protein levels on day 2. The white blood cell count (WBC) on day 2 was 13.1 +/- 1.7 X 10(3)/microliter for patients with infection and 9.7 +/- 0.3 for those without infection. Multivariate logistic regression analysis revealed that AAG, WBC, and CRP on day 2 were significant risk factors sufficiently predicting the probability of a deep sternal infection. After adjustment for these three variables, other variables (age, sex, total protein on day 2, diabetes mellitus, type of operation, duration of cardiopulmonary bypass, length of operation, repeat thoracotomy for bleeding, number of blood transfusions on the day of operation, intraaortic balloon pumping, reoperation, emergency operation, and surgeon's professional status) were not of additional significance. The goodness of fit of the statistical model was confirmed by a high correspondence between predicted and observed cases of deep sternal infection.(ABSTRACT TRUNCATED AT 250 WORDS)

C-Reactive Protein↗
PubMed1986

Laser-induced vascular lesions by cw-NdYAG or pulsed UV lasers during angioplastic procedures.

Conventional (NdYAG, Argon and CO2 lasers) laser and pulsed far ultraviolet laser radiation are able to remove arteriosclerotic tissue of the arterial wall. However, there is a striking difference between both systems: The continuous wave of conventional wave-length laser-radiation produces considerable thermal injury to the surrounding tissue, whereas the effect of pulsed far ultraviolet radiation induces less or no thermal damage despite an easily assessable tissue-removing effect. In the following study the potential of far UV laser-radiation for recanalization of occluded vessels is demonstrated in in-vitro experiments on fresh and well preserved atherosclerotic human vessels.

Animals↗
PubMed1985

[Qualitative and quantitative effects of neodymium YAG laser irradiation of the aortas of swine with reference to angioplasty].

During last few years the concept of vaporizing atheromatous plaques and thrombotic occlusions by laser energy arose. This method is a new and possibly valuable modality in the treatment of obstructive vascular diseases. We used a continuous 1,060 nm Nd-YAG laser with a focused optical wave guide. Sections of porcine aortic vessels were split longitudinally and exposed to laser radiation. Four major types of tissue alterations were observed: local swelling, disruption of the inner layers of the vessel wall, charred punched-out defects and wall perforation. Histologic examination revealed a typical damage pattern as a result of thermic injury. Clean tissue alteration is the desired effect for angioplasty. The thermic alterations limit the applicability when dealing with the cw Nd-YAG laser for this purpose.

Animals↗
PubMed1985

Risk factors for severe bacterial infections after valve replacement and aortocoronary bypass operations: analysis of 246 cases by logistic regression.

Risk factors for severe bacterial infections, that is, deep sternal wound infection, pneumonia, septicemia, and prosthetic valve endocarditis, were evaluated in 246 consecutive patients undergoing valve replacement (N = 84) or aortocoronary bypass operation (N = 162). Multiple logistic regression analysis was applied to determine the ability of putative risk factors to predict infection. The risk factors considered were age, sex, diabetes mellitus, duration of cardiopulmonary bypass (CPB), duration of operation, amount of blood restored on the day of operation, repeat thoracotomy for bleeding, intraaortic balloon pumping, reoperation, emergency operation, and the professional status of the surgeon. Severe infections occurred in similar frequency after valve replacement (8/84; 9.5%) and aortocoronary bypass (11/162; 6.8%). For patients who had a bypass procedure, repeat thoracotomy was the only factor significantly associated with infection (p = 0.0004). However, the classification analysis revealed that this variable alone is too unspecific for a reliable prediction. Univariate analysis indicated that restoration of more than 2,500 ml of blood (p = 0.0001), reoperation (p = 0.0821), duration of operation (p = 0.0061), duration of CPB (p = 0.0318), and intraaortic balloon pumping (p = 0.0281) were associated with infection following valve replacement. A model with three variables emerged from the multiple logistic regression: after correction for blood restoration, reoperation, and duration of CPB, no other variable was of additional predictive value. For patients who underwent valve replacement, the model performed well in predicting complications. The classification analysis revealed a high correspondence between observed and predicted instances of infection: it correctly predicted 75% of the patients with infection and 96% of those without infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Two years' experience with the duromedics bileaflet heart valve prosthesis.

The new Duromedics Bileaflet Cardiac Valve prosthesis has a special moving hinge mechanism for its two leaflets to wash the critical articulation area and thus reduce thrombus formation. Between October 1983 and June 1985, we implanted 278 of these prostheses in 254 patients. We did 114 aortic valve replacements, 109 mitral valve replacements, 34 double valve replacements, and two tricuspid valve replacements. Nearly 20% of the patients had had previous cardiac procedures. The hospital mortality was 5.9%. Follow-up was started with 214 surviving Austrian patients, and up to the present time, we have a follow-up period of 1704 patient months. Five patients died late after the operation (3.5 per 100 patient years). We observed 10 valve-related complications in nine patients (7 per 100 patient years). There were three cases of prosthetic endocarditis (2.1 per 100 patient years), two paravalvular leaks, and four bleeding episodes (2.8 per 100 patient years). The mechanical hemolysis was minimal, and the postoperative hemoglobin value averaged 15 g%. The LDH increased from 230 IU to 307 in the aortic valve replacements, 406 in the mitral valve replacements, and 435 in the double valve replacements. Intraoperative pressure gradients and postoperative Doppler echocardiography showed good hemodynamic performance. We conclude that good clinical results and a low complication rate can be achieved with the Duromedics Valve.

Journal Article↗
PubMed1985

Experimental coronary angioplasty using a UV-Excimer laser.

Both conventional Argon- and NdYAG-lasers in continuous wave or pulsed application and far ultraviolet laser radiation are able to cause a loss of substance of biologic tissue. The thermic and ablative effects of NdYAG-lasers and UV-Excimer lasers at the wavelengths of 193 nm (ArF) and 248 mm (KrF) on inconspicuous and atherosclerotic human and animal coronary vessels were compared by histologic and, in some cases, by scanning electron microscopic examinations. Whereas common lasers generally produce thermal injuries of the surroundings, pulsed far ultra-violet radiation is characterized by a lack of thermic damage. The UV-radiation in vitro cleaned precise defects of substance, and assessable tissue-removing effects were found. These results were influenced by the wavelength used. In general, the removing effect was good in normal and atherosclerotic tissue, whereas massive calcification was very resistant. Excimer lasers seem to be preferable for ablation of atherosclerotic tissue, but still there is a great number of technical problems to be solved until use in the clinical setting can be justified.

Journal Article↗
PubMed1985

[Coronary laser angioplasty].

Experimental studies have confirmed the feasibility of removing thrombotic material and atheromatous plaques with laser energy. Secondary to the heat generated at the site of conventional, continuous-wave laser radiation, thermic lesions of the vascular wall can be observed as adverse reactions. In the clinical setting, these lesions could prove to be of substantial potential danger. The energy emitted from the excimer laser, in the lower UV range, does not result in thermic damage. The luminal widening rendered is well delineated and the newly-created surfaces are relatively smooth. The extent of ablation is highly predictable. Problems dealing with transmissions of the UV laser energy remain to be solved. Nevertheless, high-energy, pulsed NdYAG- or argon laser systems, at least for medium-term periods, would appear to represent a useful alternative.

Angioplasty, Balloon↗
PubMed1985

[10 years' experience with the concept of breast-saving therapy in the treatment of breast cancer].

A therapeutic concept dependent on staging of breast carcinoma is presented. In 1974 we started at the 2. Surgical University Clinic Vienna to use the non ablative treatment in patients with breast cancer smaller than 2 cm. Up to 1984 102 patients underwent quadrantectomy axillary dissection, and radiotherapy. With equal therapeutic results the smaller and cosmetically preferable surgical intervention is recommended.

Austria↗