[Disorders of haemostasis in patients undergoing maintenance haemodialysis, with special reference to recurrent arteriovenous fistula thrombosis. Effects of dipyridamole (author's transl)].

Platelet functions and blood coagulation have been regularly investigated in 31 patients undergoing maintenance haemodialysis for 5 months to 6 years. Fifteen of them suffered from at least two arteriovenous fistula thrombosis during the year prior the first examination. Eleven patients, including eight with recurrent thrombosis, received 300-400 mg per day dipyridamole during 1 month to 2 years. Some abnormalities are commonly observed in the whole studied population: lowering of platelet adhesiveness, defective aggregation in the presence of both collagen and ADP 5. 10-5 M; increased level of factor V and mainly factor VIII. Mean platelet factor 3 activity was in the normal range with variations from one case to another. The only unusual feature observed in patients with recurrent thrombosis was an increase of platelet aggregation induced by ADP 0.5. 10-6 M. Neither spontaneous aggregation nor significant abnormality of plasminogen level and plasma antithrombin activity were observed. Under dipyridamole therapy, correction of platelet hyperaggregability was observed in all patients and improvement of platelet adhesiveness in half the studied cases (despite the unchanged anaemia). The treatment significantly decreased the frequency of arteriovnous fistule thrombosis in the six patients observed during two consecutive years, the first one without and the second under treatment: the total number of thrombosis was 18 during the first and 3 in the second period.