PLATELET-AGGREGATION, CORONARY-ARTERY DISEASE PROGRESSION AND FUTURE CORONARY EVENTS

The platelet-aggregatory response, platelet-release factors and markers of thrombin generation in vivo were studied prospectively in 53 patients participating in a randomized clinical trial evaluating the influence of nicardipine on the progression of coronary atherosclerosis. Coronary lesions were measured quantitatively and progression was defined as a decrease in minimum diameter by greater than or equal to 0.4 mm. At repeat angiography 24 months after study entry, 20 of the 53 patients had progression of 28 coronary narrowings. Only thrombin-induced enhanced platelet aggregation differentiated patients with from those without coronary disease progression, with an estimated adds ratio of 2.49 (95% confidence interval 1.10 to 5.66). The aggregatory response to adenosine diphosphate, collagen, epinephrine and platelet-activating factor were not different in the 2 groups of patients, nor were measurements of platelet fao tor 4, beta-thromboglobulin, thromboxane B-2, 6-keto-prostaglandin F-1 alpha and fibrinopeptide A. During 46.8 months of follow-up after repeat angiography, coronary events occurred in 11 of the 20 with and 6 of the 33 without progression (difference 37%, p = 0.013, confidence interval 11 to 63%). Those with coronary disease progression and an enhanced thrombin-induced platelet aggregation had a worse prognosis than those with no disease progression and a low thrombin-induced platelet aggregation. Thus, patients with coronary disease progression and future coronary events have an enhanced thrombin-induced platelet aggregation. This platelet abnormality may be a marker of increased risk and may play a causative role in the development of coronary events.