ABSTRACT
A study was carried out in 24 normotensive and 49 hypertensive subjects to measure the in-vivo platelet aggregation. Platelet aggregation ratio [PAR], which determines the circulating platelet aggregates quantitatively, was measured using the method of Wu and Hoak. The mean +/- SEM of PAR in the normotensive group was 0.90 +/- 0.01, whereas in the hypertensive group it decreased to 0.57 +/- 0.01 showing a significant decline [p < 0.0001]. The PAR was inversely correlated with the level of blood pressure. These results suggest increased level of circulating platelet aggregates in hypertension. This increased stickiness of platelets and hyperaggregability may lead to impeded blood flow and subsequent development of atherosclerotic complications. The results also suggest that the increased in-vivo platelet aggregation may be associated with the raised haemodynamic stress in the arterial vasculature