P8.08 HEMODYNAMICS AND LARGE ARTERY STIFFNESS IN YOUNG PREHYPERTENSIVE MEDICAL STUDENTS

Abstract

Background: Prehypertensive subjects have a markedly increased risk of developing hypertension compared to normotensive subjects. Prehypertension is therefore an excellent model to study hemodynamics and arterial stiffness in the development of hypertension. Methods: We assessed hemodynamics and arterial stiffness in normotensive (NT, blood pressure <120/80 mmHg) and prehypertensive (PHT, blood pressure (120–139/80–89 mmHg) medical students. Blood pressure (BP) was measured with a validated oscillometric device on two separate visits. On a third visit cardiac output, cardiac index (cardiac output corrected for body surface area), stroke volume and heart rate were measured using the Nexfin monitor for continuous non-invasive finger BP monitoring. Carotid-femoral pulse wave velocity (cfPWV) was measured using the Sphygmocor system. Results: We studied 15 prehypertensive subjects (BP 127±8/69±6 mmHg, 13 males, age 21.5±2 years) and 25 normotensive subjects (BP 112±7/64±6 mmHg, 8 males, age 21.1±years). Nexfin data were available for 31 subjects (22 NT and 9 PHT). Cardiac output and cardiac index were 7.0±1.2 and 3.6±0.7 L/min respectively in prehypertensive compared to 5.7±0.9 and 3.1±0.4 L/min in normotensive subjects (p=0.002, p=0.02). Stroke volume was 111 vs 101ml (p=0.13) and heart rate was 65 vs. 57bpm (p=0.06). cfPWV was higher in the prehypertensive group (5.5±0.5 vs. 5.2±0.5m/s p<0.03). Linear regression analysis showed that age (R2=0.13, β=0.39, p=0.02) and SBP (R2=0.28, β=0.53, p=0.001) are independent determinants of cfPWV. Conclusion: Young prehypertensive medical students have higher cardiac output and cardiac index than normotensive students. The increased cfPWV in the prehypertensive subjects is partially determined by higher blood pressures.