Coronary Vasomotor Dysfunction Is Associated With Cardiovascular Events in Patients With Nonobstructive Coronary Artery Disease

BACKGROUND

Coronary vasomotor dysfunction (CVDys) can be comprehensively classified on the basis of anatomy and functional mechanisms.

OBJECTIVES

The aim of this study was to evaluate the association between different CVDys phenotypes and outcomes in patients with angina and nonobstructive coronary artery disease (ANOCA).

METHODS

Patients with ANOCA who underwent coronary reactivity testing using an intracoronary Doppler guidewire to assess microvascular and epicardial coronary endothelium-dependent and endothelium-independent function were enrolled. Endothelium-dependent microvascular and epicardial coronary dysfunction were defined as a <50% change in coronary blood flow in response to intracoronary acetylcholine (Ach) infusion and a <-20% change in coronary artery diameter in response to Ach. Endothelium-independent microvascular and epicardial coronary dysfunction were defined as coronary flow reserve < 2.5 during adenosine-induced hyperemia and change in cross-sectional area in response to intracoronary nitroglycerin administration < 20%. Major adverse cardiac and cerebrovascular events (cardiovascular death, nonfatal MI, heart failure, stroke, and late revascularization) served as clinical outcomes.

RESULTS

Among the 1,196 patients with ANOCA, the prevalence of CVDys was 24.5% and 51.8% among those with endothelium-independent and endothelium-dependent microvascular dysfunction, respectively, and 47.4% and 25.4% among those with endothelium-independent and endothelium-dependent epicardial coronary dysfunction, respectively. During 6.3 years (Q1-Q3: 2.5-12.9 years) of follow-up, patients with endothelium-dependent microvascular dysfunction, endothelium-dependent epicardial coronary dysfunction, or endothelium-independent microvascular dysfunction showed significantly higher event rates compared with those without (19.5% vs 12.0% [P < 0.001], 19.7% vs 14.6% [P = 0.038] and 22.2% vs 13.8% [P = 0.001], respectively). Coronary flow reserve (HR: 0.757; 95% CI: 0.604-0.957) and percentage change in coronary blood flow in response to Ach infusion (HR: 0.998; 95% CI: 0.996-0.999) remained significant predictors of major adverse cardiac and cerebrovascular event after adjustment for conventional risk factors.

CONCLUSIONS

CVDys phenotype is differentially associated with worse outcomes, and endothelium-dependent and endothelium-independent microvascular function provide independent prognostic information in patients with ANOCA.

Prior SARS-CoV-2 Infection Is Associated With Coronary Vasomotor Dysfunction as Assessed by Coronary Flow Reserve From Cardiac Positron Emission Tomography

Background Cardiovascular complications from COVID-19 contribute to its high morbidity and mortality. The effect of COVID-19 infection on the coronary vasculature is not known. The objective of this study was to investigate the prevalence of coronary vasomotor dysfunction identified by coronary flow reserve from cardiac positron emission tomography in patients with previous COVID-19 infection. Methods and Results All patients who had polymerase chain reaction-confirmed SARS-CoV-2 infection referred for myocardial stress perfusion positron emission tomography imaging at Brigham and Women's Hospital from April 2020 to July 2021 were compared with a matched control group without prior SARS-CoV-2 infection imaged in the same period. The main outcome was the prevalence of coronary vasomotor dysfunction. Myocardial perfusion and myocardial blood flow reserve were quantified using N13-ammonia positron emission tomography imaging. Thirty-four patients with prior COVID-19 were identified and compared with 103 matched controls. The median time from polymerase chain reaction-confirmed SARS-CoV-2 to cardiac positron emission tomography was 4.6 months (interquartile range,1.2-5.6 months). There were 16 out of 34 (47%) patients previously hospitalized for COVID-19 infection. Baseline cardiac risk factors were common, and 18 (53%) patients in the COVID-19 group had abnormal myocardial perfusion. Myocardial blood flow reserve was abnormal (<2) in 44.0% of the patients with COVID-19 compared with 11.7% of matched controls (P<0.001). The mean myocardial blood flow reserve was 19.4% lower in patients with COVID-19 compared with control patients (2.00±0.45 versus 2.48±0.47, P<0.001). Conclusions Myocardial blood flow reserve was impaired in patients with prior COVID-19 infection compared with cardiovascular risk factor-matched controls, suggesting a relationship between SARS-CoV-2 infection and coronary vascular health. These data highlight the need to assess long-term consequences of COVID-19 on vascular health in future prospective studies.

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

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 coronary vasomotor dysfunction (CVDys), as assessed by repeated coronary function testing (CFT), angina, and quality of life.

BACKGROUND

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

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).