Microcirculation function assessed by adenosine triphosphate stress myocardial contrast echocardiography and prognosis in patients with nonobstructive coronary artery disease

BACKGROUND: Recent studies have demonstrated that coronary microcirculation dysfunction (CMVD) is closely correlated with adverse clinical outcomes. In this study, quantitative stress myocardial contrast echocardiography (MCE) was used to evaluate the CMVD and to investigate its association with the prognosis of patients with nonobstructive coronary artery disease (CAD). MATERIAL AND METHODS: From 2006 to 2014, 227 consecutive patients with chest pain and a diagnostic coronary angiography without significant coronary artery stenosis (<50%) who underwent adenosine triphosphate disodium (ATP) stress MCE were enrolled. Quantitative MCE measurements were analyzed using replenishment curves. RESULTS: Median follow-up time of this study was 5.3 years. Predictors of impaired coronary flow reserve (CFR) were smoking, diabetes, high apolipoprotein B, high low-density lipoprotein, serum uric acid, and low apolipoprotein A. During follow-up, 22 patients were reported to have 30 cardiac events (21 unstable angina, 3 nonfatal myocardial infarctions, 6 percutaneous coronary interventions). Using multivariate analysis, abnormal β reserve (≤1.6), impaired CFR (≤2.0), and diabetes were independent predictors of primary endpoint events in patients with nonobstructive CAD (P < .05). Multivariate analysis showed that CFR ≤2.0 (odds ratio [OR] = 25.21, 95% confidence interval [CI]: 3.01–182.32; P = .003), β reserve ≤1.6 (OR = 29.96, 95% CI: 3.5–241.27; P = .002), and diabetic (OR = 33.11, 95% CI: 3.65–300.02; P = .002) significantly increased the risk of the primary endpoint events. CONCLUSIONS: ATP stress quantitative MCE is a feasible and effective method to evaluate microcirculation abnormalities in human coronary arteries and it can be used for the clinical analysis, risk stratification, and treatment of early CAD.