Ranolazine in Symptomatic Diabetic Patients Without Obstructive Coronary Artery Disease: Impact on Microvascular and Diastolic Function

BackgroundTreatments for patients with myocardial ischemia in the absence of angiographic obstructive coronary artery disease are limited. In these patients, particularly those with diabetes mellitus, diffuse coronary atherosclerosis and microvascular dysfunction is a common phenotype and may be accompanied by diastolic dysfunction. Our primary aim was to determine whether ranolazine would quantitatively improve exercise‐stimulated myocardial blood flow and cardiac function in symptomatic diabetic patients without obstructive coronary artery disease. Methods and ResultsWe conducted a double‐blinded crossover trial with 1:1 random allocation to the order of ranolazine and placebo. At baseline and after each 4‐week treatment arm, left ventricular myocardial blood flow and coronary flow reserve (CFR; primary end point) were measured at rest and after supine bicycle exercise using 13N‐ammonia myocardial perfusion positron emission tomography. Resting echocardiography was also performed. Multilevel mixed‐effec...