Abstract
BACKGROUND: Peripheral artery disease (PAD) is associated with increased arterial stiffness, as measured by an increasing radial artery augmentation index (AIX). However, it has not yet been clearly demonstrated whether AIX is associated with adverse cardiovascular outcomes in a PAD population. MATERIALS AND METHODS: Seventy-two patients with PAD were recruited between 2011 and 2016. Radial artery applanation tonometry was performed at a baseline visit, and the central AIX, normalized to 75 beats/min, and the peripheral AIX were calculated using pulse wave analysis. Incident major adverse cardiac events (MACEs) were identified by subsequent chart review. RESULTS: Study subjects had comorbidities commonly associated with PAD including a high prevalence of hypertension (93%), hyperlipidemia (85%), coronary artery disease (39%), and diabetes mellitus (39%). During a median follow-up period of 34 mo (interquartile range 29-38), 14 patients experienced a MACE. In a univariate Cox proportional hazards model, a 10-unit increase in the peripheral AIX was significantly associated with a 54% increased rate of MACE (hazard ratio [HR] 1.54, 95% confidence interval [CI] 1.06-2.22, P = 0.02), but central AIX, normalized to 75 beats/min, was not (HR 1.33, 95% CI 0.71-2.47, P = 0.37). In a multivariable model adjusted for coronary artery disease, age, and Rutherford category the peripheral AIX remained significantly associated with MACE (HR 1.70, 95% CI 1.10-2.62, P = 0.02). CONCLUSIONS: Increased arterial stiffness, as measured by the peripheral AIX, was independently associated with an increased rate of MACE in patients with PAD. The use of radial artery tonometry should be contemplated as a tool for risk stratification in patients with PAD.