Efficacy of Diltiazem to Improve Coronary Vasomotor Dysfunction in ANOCA: The EDIT-CMD Randomized Clinical Trial

Background: Diltiazem is recommended and frequently prescribed in patients with angina and nonobstructive coronary artery disease (ANOCA), suspected of coronary vasomotor dysfunction (CVDys). However, studies substantiating its effect is this patient group are lacking.

Objectives: The randomized, placebo-controlled EDIT-CMD (Efficacy of Diltiazem to Improve Coronary Microvascular Dysfunction: A Randomized Clinical Trial) evaluated the effect of diltiazem on CVDys, as assessed by repeated coronary function testing (CFT), angina, and quality of life.

Methods: A total of 126 patients with ANOCA were included and underwent CFT. CVDys, defined as the presence of vasospasm (after intracoronary acetylcholine provocation) and/or microvascular dysfunction (coronary flow reserve: <2.0, index of microvascular resistance: ≥25), was confirmed in 99 patients, of whom 85 were randomized to receive either oral diltiazem or placebo up to 360 mg/d. After 6 weeks, a second CFT was performed. The primary end point was the proportion of patients having a successful treatment, defined as normalization of 1 abnormal parameter of CVDys and no normal parameter becoming abnormal. Secondary end points were changes from baseline to 6-week follow-up in vasospasm, index of microvascular resistance, coronary flow reserve, symptoms (Seattle Angina Questionnaire), or quality of life (Research and Development Questionnaire 36).

Results: In total, 73 patients (38 diltiazem vs 35 placebo) underwent the second CFT. Improvement of the CFT did not differ between the groups (diltiazem vs placebo: 21% vs 29%; P = 0.46). However, more patients on diltiazem treatment progressed from epicardial spasm to microvascular or no spasm (47% vs 6%; P = 0.006). No significant differences were observed between the diltiazem and placebo group in microvascular dysfunction, Seattle Angina Questionnaire, or Research and Development Questionnaire 36.

Conclusions: This first performed randomized, placebo-controlled trial in patients with ANOCA showed that 6 weeks of therapy with diltiazem, when compared with placebo, did not substantially improve CVDys, symptoms, or quality of life, but diltiazem therapy did reduce prevalence of epicardial spasm. (Efficacy of Diltiazem to Improve Coronary Microvascular Dysfunction: A Randomized Clinical Trial [EDIT-CMD]; NCT04777045).