INCREASED PLATELET AND COAGULATORY ACTIVITY INDICATE ONGOING THROMBOGENESIS IN PERIPHERAL ARTERIAL-DISEASE

In peripheral arterial disease (PAD) risk of thrombosis is high and sy stemic haemostatic derangement thought contributory. We investigated p latelet and coagulatory activity in patients with PAD and sought to fi nd the best disease indicator. Stagnation point flow adhesio-aggregome try (SPAA) enables real-time quantitative assessment of platelet adhes ion and aggregation under well-defined flow conditions. SPAA and agoni st-induced aggregometry (Born method) were performed and concentration s of fibrinogen, fibrin monomer (FM), D-dimer, and thrombin-antithromb in complex (TAT) measured in 92 PAD patients and 70 healthy volunteers . Agonist-induced aggregometry detected no differences between patient s and controls. SPAA-measured platelet adhesion and spontaneous aggreg ation (p < 0.001), and concentrations of fibrinogen (p < 0.001), FM (p < 0.001), TAT (p < 0.02) and D-dimer (p < 0.001) were all significant ly increased in patients. Neither platelet function nor coagulatory ac tivity was altered in patients receiving aspirin. Sensitivity and spec ificity in detecting PAD were as follows: SPAA (95%,93%), fibrinogen ( 36%,91%), FM (48%,84%), TAT (36%,78%), D-dimer (73%,80%). Our findings support the concept of ongoing thrombogenesis as being contributory t o the progression and possibly to the initiation of PAD. Aspirin alone did not prevent haemostatic hyperreactivity in these patients and flo w-mediated platelet function was the most sensitive and specific indic ator of advanced disease. This technique thus appears to be valuable, not only for evaluating therapeutic strategies to prevent platelet act ivation, but also in elaborating platelet-related mechanisms involved in thrombogenesis and atheroma formation.