Platelet activation and inflammatory response in patients with non-dipper hypertension

Abstract

Objective: Non-dipper hypertensives had about three times the risk of atherosclerotic events than hypertensives whose blood pressure was >10% lower at night compared to daytime (dippers). Platelet activation and inflammatory response may derive from most atherosclerotic events. Mean platelet volume (MPV) is a determinant of platelet activation and high sensitive C-reactive protein (hs-CRP) is the best candidate assay to identify and monitor the inflammatory response. We aimed to determine whether MPV and hs-CRP levels are elevated in non-dipper patients compared to dippers and healthy controls. In addition, we tried to find out if MPV and CRP are related to each other or not in non-dipper hypertensives.

Method: The total 126 patients study group included 86 patients with hypertension and 40 healthy subjects (16 male, mean age; 51+/-4) as control. Ambulatory blood pressure monitoring was performed for all patients. Hypertensive patients were divided into two groups; 46 dipper patients (18 male, mean age; 50+/-9) and 40 non-dipper patients (17 male, mean age; 53+/-11). Clinical baseline characteristics were similar between groups. We measured mean platelet volume in a blood sample collected in EDTA tubes and high-sensitive CRP was measured by using BN2 model nephlometer.

Results: Non-dipper patients demonstrated higher levels of MPV compared to dippers and normotensives (9.72+/-0.52 fl vs 9.38+/-0.33 fl and 8.92+/-0.42 fl, p<0.05, respectively). High-sensitive CRP levels were also significantly higher in non-dippers compared to dippers and normotensives (4.9+/-1.7mg/l vs 3.8+/-1.5mg/l and 2.7+/-0.8mg/l, p<0.05, respectively). There was significant positive correlation between MPV and CRP levels (p=0.002, r=0.482) in non-dipper hypertensives.

Conclusion: Our results suggest that patients with non-dipping tend to have increased platelet activation and inflammatory response. Increased platelet activation and inflammatory response could contribute to increase the atherosclerotic risk in non-dipper patients compared to dippers.