Pilot Study to See for Postural Variation of Augmentation Indexin Non-Hypertensive and Hypertensive Subjects on Medications

Abstract

Objectives: Augmentation index (AI), as a surrogate measure of arterial stiffness and cardiovascular mortality. The current study focused on the variations in AI in both supine and sitting position for patient without hypertension and subjects with hypertension, and looked for effects of different anti-hypertensive medications on postural variations in AI. Methods: This study analysed AI in both supine and sitting position for patients without hypertension (n = 21) and hypertensive subjects (n = 17- ongoing recruitment). Variations in AI with postural changes were compared between hypertensive and non-hypertensive subjects; and subsequently compared among hypertensive patients using ACEI/ARB, beta-blocker, calcium channel blocker and diuretics to see effects of different anti-hypertensives on postural AI variations. Measurement were done by SphygmoCor, gold standard for non-invasive central pressures assessment. Differences between characteristics at supine and sitting position were compared using non-parametric paired test of Wilcoxon signed-rank test in normotensives and via paired t test and student's t test in hypertensive age group. A value of P < 0.05 was accepted as statistically significant. Results: In normotensive subjects, aortic AI significantly increased from sitting to supine position (P < 0.05), whereas significant postural changes of AI was not seen in hypertensive patients. AI significantly decreased with posture from sitting to supine in subgroup of patients on ACE inhibitors (P = 0.05). Conclusions: Our findings suggest that augmentation index increased from sitting to supine position in non-hypertensive subjects but there was reversal or blunting of this phenomenon on anti-hypertensives.