Relationship between percentage of mean arterial pressure at the ankle and mortality in participants with normal ankle-brachial index: an observational study.

Abstract

Peripheral arterial disease (PAD) is associated with all-cause mortality. Ankle-brachial index (ABI) is the most widely used tool for detecting PAD, but can yield false-negative results in patients with non-compressible vessels. Pulse volume recording may be an alternative tool for assessing PAD in such patients. However, the association between pulse volume recording and all-cause mortality has seldom been reported. We hypothesised that the percentage of mean arterial pressure (%MAP) and upstroke time (UT), which are indexes of the arterial wave obtained on pulse volume recording, can predict mortality. We conducted this as a retrospective cohort study. Data were collected from the Taichung Veterans General Hospital. We included 314 participants with complete data on ABI and pulse volume recording performed between June 2007 and November 2011. Mortality data served as the follow-up outcome. Mortality data were obtained from the Collaboration Center of Health Information Application, Ministry of Health and Welfare, Executive Yuan, Taiwan. Participants with ABI ≤ 0.9 showed a highest mortality rate (p<0.001 in the log-rank test), but the mortality rate was not significantly different between participants with 0.9<ABI≤1.1 and those with 1.1<ABI≤1.3 (p=0.553). Among the participants with 0.9<ABI≤1.3, the high %MAP (>45%) group showed a higher risk of all-cause mortality than the low %MAP (≤ 45%) group (HR=5.389, p=0.004) after adjustment for ABI, pulse wave velocity, UT, age, sex, blood pressure, serum cholesterol, and history of cardiovascular disease and diabetes. We thus demonstrated that a high %MAP based on pulse volume recording in participants with 0.9<ABI≤1.3 could predict all-cause mortality during 20.3 months of follow-up.