A Comparison of Oscillometrically Measured Ankle-to-Brachial Mean Arterial Pressure Ratio and Ankle-Brachial Index in Predicting Cardiovascular Events and All-Cause Mortality.

Background: The oscillometrically measured ankle-brachial index (omABI), which is determined by the ratio of ankle to brachial systolic blood pressure measured through oscillography, has been demonstrated as a robust predictor of cardiovascular events. However, the reliability of mean arterial pressure measured by oscillography may be higher than that of systolic blood pressure based on the principle of oscillographic oscillation. We aimed to compare the predictive value of oscillometrically measured ankle-tobrachial mean arterial pressure ratio (omMAPR) and omABI for cardiovascular events and all-cause mortality.

Methods: The observation cohort consisted of a total of 37 803 employees from the Chinese Kailuan Group who underwent limb blood pressure measurements during their participation in physical examination between 2010 and 2017.

Results: After an average follow-up period of 3 years, a total of 589 cardiovascular events and 570 cases of all-cause mortality were observed. The predictive performance of omMAPR was found to be slightly superior to omABI in terms of cardiovascular events (C-statistics: 0.55 vs. 0.51, P < .001) and all-cause mortality (C-statistics: 0.60 vs. 0.55, P <.001). After adjusting for confounders, within a specific range (omMAPR ≤ 1.06 or omABI ≤ 1.12), each 0.1-unit increase in omMAPR was associated with reductions of 14% (HR = 0.86, 95% CI: 0.77-0.96) and 23% (HR = 0.77, 95% CI: 0.70-0.84) in cardiovascular events and all cause mortality, respectively, while each 0.1-unit increase in omABI was associated with reductions of 12% (HR = 0.88, 95% CI: 0.79-0.97) and 22% (HR = 0.78, 95% CI: 0.72-0.85) in cardiovascular events and all-cause mortality, respectively. However, once out of that range (omMAPR > 1.06 or omABI > 1.12), neither omMAPR nor omABI was significantly associated with cardiovascular events or all-cause mortality.

Conclusion: Both omMAPR and omABI within specific ranges (omMAPR ≤ 1.06 or omABI ≤ 1.12) were independent predictors for cardiovascular events and all-cause mortality. Moreover, omMAPR exhibited a slightly superior predictive ability compared to omABI in relation to cardiovascular events and all-cause mortality. The trial registration number is ChiCTR-TNRC-11001489.