ELEVATED PLATELET REACTIVITY IN PATIENTS WITH UNCONTROLLED HYPERTENSION: THE EFFECT OF CHA2DS2-VASC SCORE

Abstract

Objective: Hypertension is associated with vascular and endothelial dysfunction that may result in a greater propensity for reactive platelets to cause thrombosis. Purpose: The aim of this study was to evaluate multiple platelet activation pathways in hypertensive patients with different level of blood pressure control and cardiovascular risk factors. Design and method: Thirty nine uncontrolled (office SBP > 140 mmHg and ambulatory daytime SBP >135 mmHg, 27 males, aged 58 ± 9 years) and 32 well controlled (office SBP < 140 mmHg and ambulatory daytime SBP < 135 mmHg, 21 males, aged 58 ± 8 years) essential hypertensive patients were included in the study. Twenty four healthy individuals (12 males, aged 53 ± 10 years) were served as control group. Blood samples were obtained before and 48 hours after the procedure and platelet aggregation was tested in platelet rich plasma after activation with arachidonic acid (AA), adenosine diphosphate ADP), collagen (Col), epinephrine (Epi) and ristocetin (Risto), by using AggRAM Platelet Aggregation Analyzer. Results: Hypertensive patients showed elevated platelet reactivity in all platelet activation pathways compared to normotensive group (AA: 88.8 ± 6.8% versus 79.5 ± 7.3%, ADP: 86.8±9.1% versus 71.5±7.7%, Col: 86.5 ± 5.7% versus 73.9 ± 6.7%, Epi: 92.6±5.4% versus 80.5 ± 5.7%, Risto: 93.8 ± 6.8% versus 79.9 ± 6.3%, p <0.05 for all). Col, Epi and Risto platelet activation pathway showed a statistically significant increase in patients with uncontrolled hypertension compared to the group with well controlled hypertension (AA: 88.8 ± 6.1% versus 89.1 ± 4.1%, ADP: 89.8 ± 4.1% versus 87.5±4.7%, Col: 87.5±4.7% versus 81.9 ± 6.7%, Epi: 93.6 ± 4.4% versus 80.1 ± 5.7%, Risto: 94.8 ± 3.8% versus 80.9 ± 4.3%,). Notably, strong correlations were found between the Col platelet pathway activation and Risto platelet pathway activation and CHA2DS2-VASc score (r = 0.57, p <0.001 and r = 0.61, p <0.001, respectively) in hypertensive patients. Conclusions: Patients with uncontrolled hypertension showed elevated platelet reactivity. Patients with high CHA2DS2-VASc even without atrial fibrillation carry also a higher risk of thrombosis as indicated by the increased platelet aggregation under certain pathways of activation.