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Biomedical subjects

M Kandrach

Publications and source records attributed to M Kandrach.

5 recordsLinked to original sources

Porcine cardiac xenograft valves: analysis of survival, valve failure, and explantation.

Porcine cardiac xenografts were used for cardiac valve replacement in 1,093 patients. Hospital mortality for aortic valve replacement (AVR) was 3.7%; for mitral valve replacement (MVR), 7.8%; and for AVR + MVR, 4.7%. Total follow-up was 2,036 patient-years; maximum, 7.3 years; and mean, 1.89 years. Actuarial survival (+/- standard error of the mean) for AVR was 84% +/- 2% at 56 months; for MVR, 84% +/- 3% at 56 months; and for AVR + MVR, 86% +/- 4% at 30 months. Nonfatal thromboembolism occurred in 8 of 1,030 patients (0.78%). Anticoagulation was not routinely employed. Fifty hospital survivors (4.8%) experienced valve dysfunction; 18 of the survivors (1.7%) died; and 32 of the survivors (3.1%) underwent reoperation. The rate of dysfunction increased slowly until the sixth year when an increased rate was observed (p less than 0.0001). Patients less than 34 years old had a higher incidence of dysfunction (p less than 0.01). Thirty-two hospital survivors (3.1%) underwent explantation of the porcine valve for late dysfunction. Valve dysfunction secondary to endocarditis and paravalvular leak occurred early, while leaflet deterioration or thrombosis was more gradual in onset and was noted later. The porcine valve has functioned well for 1 to 7 years with a low incidence of valve related morbidity and mortality without routine anticoagulation in patients older than 34 years of age.

Aortic Valve↗

Concomitant carotid and coronary artery reconstruction.

Data are presented on 68 patients who underwent concomitant carotid endarterectomy (CE) and coronary artery bypass surgery (CAB) at Emory University Hospital from January 1974 to February 1981. This group is then compared with a randomly selected, matched population without known carotid disease who underwent CAB alone. Asymptomatic bruit was the reason for investigation in 40 patients (59%); another 23 patients (34%) experienced transient cerebral ischemic attacks (TIAs); and five patients (7%) had TIA and prior stroke. Carotid stenoses (>75% luminal narrowing) were demonstrated as follows: isolated left, 24 patients; isolated right, 27 patients; and bilateral lesions, 16 patients. One patient had innominate artery stenosis. Associated total occlusion of one or both vertebral arteries was demonstrated in six patients. Ninety-seven per cent of patients had disabling angina pectoris prior to operation; the angina was unstable in 57%, 15% had congestive heart failure, and 54% had had at least one prior myocardial infarction (MI). Single-vessel coronary disease was present in 12.5% of patients, double in 37.5%, triple in 41.1%, and left main stenosis in 9%; 43% of patients had abnormal ventricular contractility. CE was performed on 67 patients (36 left and 31 right); aortocarotid bypass was performed on one. The CE procedures were performed immediately prior to the sternotomy for CAB under the same anesthesia. CAB consisted of single bypass in eight patients (11.8%); double in 16 patients (23.5%); triple in 22 patients (32.4%); and quadruple or more in 22 patients (32.4%) (mean = 2.9 grafts per patient). There was no hospital mortality. Perioperative MI occurred in 2.0% and stroke with residual deficit in 1.3%. Cumulative survival is 98.5% at two years. Sixty-three patients (92%) reported improvement or elimination of anginal symptoms after operation. Rehospitalization for stroke was necessary in 3.7% patients. Postoperative activity levels are; self-care only, 3.9%; normal daily activity only, 17.6%; moderate exercise capability, 45%; and vigorous exercise capability, 33%. Comparison was made with a group of 84 randomly selected patients who underwent CAB alone during the same time interval. Data revealed no significant difference between the groups regarding sex, angina subset, ventricular function, coronary anatomy, vessels grafted, perioperative stroke or MI, mortality, or postoperative activity capability. Older age (59.8 vs. 55.6, p < 0.01) and less complete coronary revascularization possible (66 vs. 84%, p < 0.05) in the CECAB group were the only significant differences. Carotid stenosis co-existing in patients requiring CAB should be concomitantly corrected with the same risk and results expected from CAB alone.

Aged↗

A new method of preparing Ca2+-ATPase from sarcoplasmic reticulum: extraction with octylglucoside.

A fast method for preparing Ca2+-ATPase from rabbit muscle sarcoplasmic reticulum was devised. The method involves extracting extrinsic membrane proteins with the non-ionic detergent octylglucoside at high salt concentration. A Ca2+-ATPase of consistently high specific activity (about 25 mumoles/mg.min) is found in the insoluble residue. The method was optimized with respect to the concentrations of detergent and salt, pH, and other extraction conditions. By the criteria of the protein pattern in SDS-polyacrylamide gel electrophoresis, dependence of the hydrolytic activity on the presence of Ca2+, and the phosphoprotein formation, the preparation is identical with the Ca2+-ATPase isolated previously by MacLennan [10] and other authors. The main advantages of the new method are its rapidity, its reliability, and the high specific activity of the purified enzyme.

Animals↗