Abstract 12292: Noninvasively Obtained Augmentation Index is Not a Reliable Maker for Vascular Sclerosis in Elderly Subjects
Backgrounds: The augmentation index (AI) has been widely used as a clinical index of arterial stiffness. However, we sometimes experienced that the AI did not show abnormal values in very elderly people with severe atherosclerosis. The purpose of this study is to evaluate the efficacy noninvasive AI in patients with coronary artery disease (CAD).
Methods: One hundred twenty patients (69±10 year-old, 83 male) undergoing cardiac catheterization for clinical purpose have been enrolled in this study. Invasive central blood pressure (cBP) was measured by fluid-filled manometer system. The noninvasive cBP and AI were calculated in the end of catheterization using SphygmoCor approved by the U.S. Food and Drug Administration. The noninvasive brachial blood pressure (BP) was calculated by oscillometric method.
Results: Noninvasive systolic cBP was lower than invasive systolic cBP (115±18 vs. 130±23 mmHg, p≤0.001) and noninvasive diastolic cBP was higher than invasive diastolic cBP (67±10 vs. 63±10 mmHg, p≤0.001) in all the subjects. Ninety-nine patients was diagnosed as CAD and the other 21 patients were classified into non-CAD group. There was no significant difference in antihypertensive drugs, pulse rate, noninvasive brachial BP, age, gender and height between the two groups. The invasive systolic cBP was similar between the CAD group and the non-CAD group (130±23 vs. 130±24 mmHg, p=0.886), while invasive diastolic cBP in the CAD group was lower than that in the non-CAD group (62±10 vs. 68±9 mmHg, p=0.020). Surprisingly, there was no significant difference in the AI between the CAD and the non-CAD groups (24±10 vs. 24±14 %), and the AIs in both groups were within the normal range for age.
Conclusions: SphygmoCor underestimated the systolic cBP and AI in elderly. Because SphygmoCor was originally made to estimate central pressure by means of invasive radial artery blood pressure, while most users uses oscillometric brachial BP instead. This may leads wrong interpretation of low AI in elderly subjects. The algorithm for estimating central BP should be re-created using oscillometric BP.
- © 2013 by American Heart Association, Inc.