Objectives: Increased platelet activation plays an important role in the development of atherosclerosis. Mean platelet volume (MPV) is a determinant of platelet activation. In our study, we aimed to determine whether MPV levels are elevated in non-dipper patients compared with dippers and healthy controls. In addition, we tried to find out if MPV levels are correlated with blood pressure measurements in hypertensive patients.
Methods: This cross-sectional study included 56 hypertensive patients; 27 age- and sex-matched healthy volunteers were enrolled to study as a control subjects. Ambulatory blood pressure monitoring was performed for all patients. Hypertensive patients were divided into two groups: 28 dipper patients (10 male, mean age 51 +/-8 years) and 28 non-dipper patients (11 male, mean age 53+/-10 years). MPV was measured in a blood sample collected in EDTA tubes and was also used for whole blood counts in all patients.
Results: In non-dipper patients, 24-h systolic blood pressure (141.5+/-10.21 vs 132.3+/-7.7 mmHg, p<0.001), 24-h diastolic blood pressure (88.2+/-8.5 vs 81.0+/-8.2 mmHg, p<0.01) and 24-h average blood pressure (105.7+/-8.5 vs 97.7+/-7.4 mmHg, p<0.001) are significantly higher than dippers. Whereas daytime measurements were similar between dippers and non-dippers, there was a significant difference between each group during night-time measurements (night-time systolic 137.1 +/-11.0 vs 120.2+/-8.0 mmHg, p<0.001; night-time diastolic 85.3+/-8.0 vs 72.8+/-7.9 mmHg, p<0.001). Non-dipper patients (9.61 +/-0.42 fl) demonstrated higher levels of MPV compared with dippers (9.24+/-0.35 fl) and normotensives (8.87+/-0.33 fl) (p<0.001 and p<0.001, respectively). There was significant correlation between MPV and ambulatory diastolic and systolic blood pressure in non-dipper hypertensives.
Conclusion: Our results suggest that MPV, a determinant of platelet activation, has a positively correlation with blood pressure and elevated in non-dipper compared with dippers and controls. Increased platelet activation could contribute to increase the atherosclerotic risk in non-dipper patients compared with dippers.