The effect of an infusion of low molecular weight dextran on peripheral resistance in patients with arteriosclerosis

The effect of aspirin and prostaglandin E(1) on the patency of microvascular anastomosis in the rats

The purpose of this study was to evaluate the effect of oral prostaglandin E(1)(PGE(1)) on the patency of the microvascular anastomosis of the carotid artery in rat. A total of 48 rats were used, and divided into three groups. The first group (A) was used as a control with no medical agent being used after anastomosis, the second group (B) was medicated with aspirin, and the third group (C) was medicated with oral PGE(1). In each group, four rats were sacrificed serially on every post-operative 3, 5, 10 and 15 days after arterial anastomosis. Patency and histologic evaluations at the anastomotic site were observed. The results revealed that the PGE(1) therapied group showed highest patency rate (100%), lesser formation of mural thrombosis, and also minimal changes in the intimal hyperplasia and medial fibrosis. From these findings, we could conclude that PGE(1) has superior effect on maintaining the patency after microvascular surgery.

Effects of venesection on leg blood flow in claudicants with high-normal haematocrit

Patients with intermittent claudication frequently have high-normal levels of haematocrit and hence blood viscosity, which may contribute to decreased calf blood flow on exercise, and hence to the symptom of claudication. Reduction in haematocrit and viscosity by serial venesection in eight patients with stable claudication and high-normal haematocrit (mean 0.50) was performed, and the effects on claudication, calf blood flow, and calf oxygen delivery were studied. Following reduction in haematocrit to low-normal levels (mean 0.44), resting calf blood flow was unchanged; peak flow after ischaemic exercise increased slightly (+17%), but peak oxygen delivery (peak flow X haemoglobin concentration) was unchanged. Hence any increase in calf blood flow in the symptomatic leg is balanced by a decrease in oxygen-carrying capacity after venesection. No increase in claudication time would therefore be expected, and none was observed in the present study.

Prognostic value of initial blood viscosity on vascular surgery and treatment in peripheral disease

The correlation between extent of arteriosclerosis and blood viscosity, and the reduction in viscosity after successful surgery support the hypothesis that a raised viscosity is a consequence rather than a cause of arteriosclerosis. Measurement of blood viscosity was of little practical help to our team of vascular surgeons when they were faced with the problem of which reconstruction to do and when to do the procedure on a particular patient. The results of our studies show that in patients with arteriosclerosis, in whom only the major arteries are affected, the viscosity of the blood is not grossly abnormal and a knowledge of the blood viscosity does little to influence treatment. Patients with peripheral vascular disease affecting the small arteries and arterioles often have a high blood viscosity. In these circumstances manipulation of blood viscosity by hemodilution or drugs may be of benefit, and there is evidence that isoxsuprine given intravenously can achieve a reduction in viscosity.