Effect of dextran 70 and saline on thrombus formation following arteriotomy and intimectomy in small arteries.

Twenty-four arteries of rabbit ears, divided into three groups of eight, were prepared and 32P-platelets injected. Arteriotomy (7 mm) and intimectomy (5 mm) were performed and in vivo platelet accumulation followed for 2 hours. Group A comprised untreated control animals, group B was treated with 17 ml saline/kg bw, and group C with 1 g dextran and 17 ml saline/kg bw (Macrodex). Significant differences in platelet accumulation were observed only between the control and Macrodex groups at 105 and 120 minutes. In the control and saline groups four of eight vessels showed poor or no patency. All Macrodex vessels showed good patency. Control and saline vessels had large amounts of red thrombotic material, except for three saline cases with small amounts. After Macrodex treatment five of eight vessels were apparently clean, while the other three showed only small amounts of red thrombotic material. Dextran seems not to influence platelet function but rather to inhibit fibrin stabilization and probably increases fibrinolysis. Vascular patency was only endangered by the formation of solid fibrin-containing red thrombi.