The sensitivity of tests to detect in vivo platelet activation induced by the removal of arterial endothelium of the baboon (Papio ursinus).

The relative sensitivities for the various in vivo and in vitro tests for platelet activation are unknown. This was studied in a baboon model where limited and more substantial injury to the vascular endothelium was inflicted. The endothelium of a segment of the right carotid artery was removed with a balloon catheter on day 0 (limited de-endothelialisation), and that of the left carotid artery, abdominal aorta and left femoral artery on day 7 (substantial de-endothelialisation). Eight baboons (Papio ursinus) were used. Baseline tests for platelet activation (platelet volume, platelet density, platelet aggregate ratio, and platelet and plasma levels of platelet factor 4 [PF4] and beta-thromboglobulin [beta-TG]) were performed 7 days before de-endothelialisation and repeated on days 1, 9 and 16. The kinetics of indium-111-labelled platelets were measured after substantial de-endothelialisation. Sham operations were done on 3 animals exactly as in the test, except that the balloon injuries were not inflicted. No influence on the results of the platelet function tests was found. The only test capable of detecting limited injury to the endothelium was the measurement of plasma PF4. The mean platelet life-span (MPLS) shortened, mean platelet density decreased, the circulating platelet aggregate ratio decreased, and plasma levels of PF4 and beta-TG increased (P less than 0.05 in all instances) after the substantial endothelial injury. The mean platelet volume, intraplatelet PF4 and beta-TG, and the in vivo distribution and sites of sequestration of labelled platelets were poor tests for in vivo platelet activation.(ABSTRACT TRUNCATED AT 250 WORDS)

[Crescendo angina - an indication for surgery: A short literature survey and a discussion of three cases]. / Crescendo angina -- 'n aanduiding vir chirurgie ' Kort literatuuroorsig en bespreking van 3 gevalle.

A definition of crescendo angina is given, followed by a short discussion of the literature on this disease. A case of a patient treated surgically for crescendo angina is reported, and the angiograms of 2 other patients are reviewed to further illustrate the problem. The favourable postoperative course of the patients who underwent an operation for this life-threatening disease is a strong indication for this mode of treatment.

Coronary artery bypass surgery at the University of the Orange Free State Medical School.

Fifty patients underwent aortocoronary bypass grafting, and 48 of these survived and are alive at present. Seventy-four per cent of these patients were relieved of angina, 16% were improved, and 10% remained the same, and 72% of these patients have resumed their normal daily work. The morbidity of the operation was negligible. The problems that emerged in this small series were involvement of the perforator artery, sudden occlusion of a major vessel during coronary angiography, preservation of the myocardium during surgery for multiplevessel disease, and lastly the question of when a ventricle is too damaged to be operated on. These problems are discussed and suggestions are made as to how to handle them. On the whole, we see this procedure as a useful adjunct in the treatment of occlusive coronary artery disease.