Ranolazine and Microvascular Angina by PET in the Emergency Department: Results From a Pilot Randomized Controlled Trial

Purpose: Coronary microvascular dysfunction (CMD) is a common but underdiagnosed cause of chest pain. Literature is scant regarding effective treatments. We explored the effect of ranolazine on coronary flow reserve (CFR) among symptomatic patients with CMD. Methods: This pilot double-blinded randomized controlled trial included emergency department patients with chest pain and CMD admitted to an observation unit between June 2014 and November 2015. Participants were assessed by cardiac Rb-82 positron emission tomography and computed tomography imaging at baseline and 30 days. CMD was defined as CFR <2 corrected for rate pressure product or <2.5 uncorrected, with no evidence of obstructive or nonobstructive coronary artery disease or calcification. Patients with infarction, hypertensive urgency, heart failure, or prescribed QTc-prolonging drugs were excluded. Participants were assigned to ranolazine or placebo in a 2:1 ratio. Primary outcome was change in CFR at 30 days. Findings: We enrolled 31 patients (71% female, mean [SD] age 50 [6] years) with CMD (mean [SD] corrected CFR 1.6 [0.3]). Ranolazine improved CFR at 30 days by 17% (P = 0.005) compared with 0% with placebo (P = 0.67). However, there was no significant difference in the primary outcome as measured by mean change in CFR (0.27 ranolazine compared with 0.06 placebo; 95% CI, -0.08 to 0.62). (C) 2017 Elsevier HS Journals, Inc. All rights reserved.