The effect of naftidrofuryl on red blood cell aggregation detected in vitro with ultrasound.

Red blood cell aggregates are mainly responsible for the echogenicity of flowing blood. Thus, ultrasound can be used to observe the degree of red blood cell aggregation in slow flow conditions. We quantified blood echogenicity to study aggregation tendency of red blood cells in blood of patients with claudication, patients with suspected venous thrombosis, and normal volunteers without and with in vitro addition of naftidrofuryl (10(-6) M). Normal volunteers showed lower original echogenicity than any group of patients, and claudication patients showed the highest echogenicity. Naftidrofuryl caused a fall in mean echogenicity in all groups, and its effect was pronounced on blood samples with a high original echogenicity.