PP.LB01.03

Abstract

Objective: Augmentation index (AI), is a measure of arterial stiffness and cardiovascular mortality. Postural variation of AI has not been described in literature. We observed that the AI increased in supine position in most non hypertensive volunteers not on treatment. Design and method: This study analysed AI in both supine and sitting position for patients without hypertension (n = 21) and hypertensive subjects on treatment (n = 21). 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. Wilcoxon signed-rank test and paired t test were used foir statistical analysis. 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 on treatment. AI on the contrary, significantly decreased with posture from sitting to supine in subgroup of patients on ACE inhibitors (P = 0.05). Conclusions: AI increases in supine posture in subjects who are not on treatment but this effect is abolished or blunted when patients are on anti-hypertensives. These findings may suggest that patients who are hypertensive's not on treatment may have a greater increase in supine AI; thus pre-disposing them to early morning cardiovascular events. Further studies need to be done to establish these findings.