Measurement of endothelial dysfunction via peripheral arterial tonometry predicts vasculogenic erectile dysfunction

Endothelial cell dysfunction is associated with cardiovascular disease and vasculogenic erectile dysfunction (ED). Measured via peripheral artery tonometry (PAT), endothelial dysfunction in the penis is an independent predictor of future cardiovascular events. The aim of the study was to determine whether measurement of endothelial dysfunction differentiates men with vasculogenic ED identified by duplex ultrasound from those without. A total of 142 men were retrospectively assessed using patient history, penile duplex ultrasonography (US) and PAT (EndoPAT 2000). ED was self-reported and identified on history. Vasculogenic ED was identified in men who exhibited a peak systolic velocity (PSV) of ⩽ 25 cm s(-1) at 15 min following vasodilator injection. The reactive hyperemia index (RHI), a measurement of endothelial dysfunction in medium/small arteries, and the augmentation index (AI), a measurement of arterial stiffness, were recorded via PAT. Penile duplex US was used to categorize men into those with ED (n = 111) and those without ED (n = 31). The cohort with ED had a PSV of 21 ± 1 cm s(-1) (left cavernous artery) and 22 ± 1 cm s(-1) (right cavernous artery). The control group without ED had values of 39 ± 2 cm s(-1) (left) and 39 ± 2 cm s(-1) (right). Given the potential for altered endothelial function in diabetes mellitus, we confirmed that hemoglobin A1c, urinary microalbumin and vibration pulse threshold were not different in men with vasculogenic ED and those without. RHI in patients with ED (1.85 ± 0.06) was significantly decreased compared to controls (2.15 ± 0.2) (P<0.05). The AI was unchanged when examined in isolation, and when standardized to heart rate. Measurement of endothelial function with EndoPAT differentiates men with vasculogenic ED from those without. RHI could be used as a non-invasive surrogate in the assessment of vasculogenic ED and to identify those patients with higher cardiovascular risk.