A Pilot Study on the Effect of Angiotensin Receptor Blockers on Platelet Aggregation in Hypertensive Patients- A Prospective Observational Study.

INTRODUCTION: Thrombosis is an invariable component contributing to cardiovascular events in patients with hypertension. One of the risk factors of cardiovascular disease is increased platelet activity. One among the widely used antihypertensive agents are Angiotensin II type 1 Receptor Blockers (ARBs). Even though there are many studies involving antihypertensive agents, their antithrombotic properties remain elusive and not fully characterized.

AIM: To evaluate the anti-aggregatory effect of ARBs on platelets in-vivo.

MATERIALS AND METHODS: A total of 60 subjects were included in this observational pilot study conducted in the medicine out patient department of JJM Hospital, Davanagere, Karnataka, India. Among them, 30 patients with essential hypertension attending Medicine OPD of a tertiary care hospital, who were on ARB for at least one month, were enrolled into study group. The control group consisted of 30 normotensive subjects who were not on any drug affecting platelet function. The Bleeding Time (BT) was evaluated for both the groups using Duke method of BT estimation. Data was analysed using SPSS software version 20. The test group was compared with control group using student's unpaired t-test.

RESULTS: The mean BT of study group was 2.488 minutes ± 0.0361 Standard Error of Mean (SEM) and that of control group was 1.998 minutes ± 0.0362 SEM. The result was statistically significant (p<0.001). The average duration of treatment was 2.933 years.

CONCLUSION: ARB have antiplatelet activity. Increase in BT in ARB group when compared with that of control group is a reflection of antiplatelet activity.