Prognostic Value of Qualitative and Quantitative Vasodilator Stress Myocardial Perfusion Echocardiography in Patients with Known or Suspected Coronary Artery Disease

Abstract

Background: Quantification of myocardial blood flow reserve in patients with coronary artery disease using real-time myocardial perfusion echocardiography (RTMPE) has been demonstrated to further improve accuracy over the analysis of wall motion and qualitative analysis of myocardial perfusion. The aim of this study was to determine the prognostic value of qualitative and quantitative analyses obtained by RTMPE in patients with known or suspected coronary artery disease. Methods: From March 2003 to December 2008, 227 consecutive patients with normal left ventricular function who underwent RTMPE were prospectively studied. Replenishment velocity reserve (beta) and myocardial blood flow reserve were derived from RTMPE. Primary outcomes were cardiac death, myocardial infarction and unstable angina with need for urgent coronary revascularization, and secondary outcomes were coronary bypass graft surgery or angioplasty. Results: During a median follow-up period of 32 months (range, 5 days to 6.9 years), 19 major events (two deaths, six myocardial infarctions, and 11 episodes of unstable angina) and 46 total events occurred. Wall motion (hazard ratio [HR], 2.8; 95% confidence interval [CI], 1.4-5.6; P = .003) and qualitative myocardial perfusion analysis (HR, 4.3; 95% CI, 2.1-8.5; P < .001) were predictors of total events but not primary events. Abnormal myocardial blood flow reserve and abnormal b reserve were predictors of total events (HR, 8.1; 95% CI, 3-21; P < .001; and HR, 16.5; 95% CI, 5.5-49; P < .001) and primary events (HR, 3.8; 95% CI, 1-15; P = .048; and HR, 8.7; 95% CI, 1.8-40; P = .005). On multivariate analysis, only abnormal b reserve was an independent predictor of total (HR, 10.6; 95% CI, 2.5-43; P = .001) and primary (HR, 10.5; 95% CI, 1.5-6; P = .015) events. Abnormal b reserve added incremental value in predicting primary events (chi(2) = 2.0-13.2; P = .014). Conclusions: Quantitative adenosine stress RTMPE added independent and additional prognostic information over wall motion and qualitative myocardial perfusion analysis in patients with known or suspected coronary artery disease and normal left ventricular function.