Platelet aggregates and ADP-induced platelet aggregation in essential hypertensive Nigerian with sickle-gene trait (HBAS)

Abstract

Hypertension is a condition characterized by haemodynamic vascular stress and abnormal blood flow under high pressure and it is associated with complications that are, paradoxically, thrombotic rather than haemorrhagic. Spontaneous platelet aggregation has been known to be present in hypertension which predicts vascular occlusion. Similarly, increased platelet aggregation ratio (PAR) and ADP induced platelet aggregation (ADP-IPA) in response to endothelin and other factors that could contribute to thrombosis also occurs. We have studied an aspect of platelet function with a view to highlight its contribution towards the pathogenesis of thrombotic complications in hypertension. We measured platelet count (PC), platelet aggregation ratio (PAR) and ADP-induced platelet aggregation (ADP-IPA) in fortytwo (42) hypertensive and thirty (30) normotensives Nigerians using standard laboratory procedures. Platelet aggregation ratio and ADP induced platelet aggregation were significantly increased (P<0.05) in hypertensive subjects than normotensive controls with a concomitant significantly lower platelet count (P<0.05, respectively). There was a significant increase only in platelet aggregate ratio in both hypertensive subjects and controls with genotype AA than AS groups but not with ADP -induced aggregation. While hypertensive males have increased ADP induced platelet aggregation than females (P<0.05), there was no sex difference in normotensive controls. We conclude that increased platelet aggregation may be a major determinant of thrombotic complication in hypertensive Nigerians, especially in males and patients with genotype AA.