Adenosine diphosphate-induced platelet aggregation in the states of hypercoagulability.

One hundred and seven patients with congestive heart failure, myocardial infarction and arteriosclerotic heart disease were studied by adenosine diphosphate-induced platelet aggregation, fibrinogen levels and ethanol gelation test. Both increases and decreases in platelet aggregation were observed. A significantly high percentage of patients showed a decreased platelet aggregation which was especially marked in the more acute as opposed to the less acute phase. In addition, most patients exhibited a marked shift from abnormal to normal platelet aggregation or vise-versa within a short time period. This pattern of platelet aggregation suggests an active role of platelets in the states of hypercoagulability. The hypercoagulability of these patients was further substantiated by a high percentage of positive ethanol gelation tests and high fibrinogen levels.