Elevated augmentation index derived from peripheral arterial tonometry is associated with abnormal ventricular-vascular coupling

Summary Background: Although typically derived from the contour of arterial pressure waveform, augmentation index (AIx) may also be derived from the digital pulse volume waveform using finger plethysmography (peripheral arterial tonometry, PAT). Little is known regarding the physiologic correlates of AIx derived from PAT. In this study, we investigated the relation of PAT‐AIx with measures of ventricular–vascular coupling. Methods: Pulse volume waves were measured via PAT and used to derive AIx. Using 2‐dimensional echocardiography, effective arterial elastance index (EaI) was estimated as end‐systolic pressure/stroke volume index. Left ventricular (LV) end‐systolic elastance index (ELVI) was calculated as end‐systolic pressure/end‐systolic volume index. Ventricular–vascular coupling ratio was defined as EaI/ELVI. Results: Given the bi‐directional nature of ventricular–vascular uncoupling as measured by echocardiography, patients were separated into three groups: low EaI/ELVI (1·2, n = 10). Adjusting for potential confounders (age, mean arterial pressure, height and heart rate), patients with optimal EaI/ELVI had lower AIx (1 ± 4%, P