Long-Term Association of Dipyridamole Stress Myocardial Contrast Echocardiography versus Single-Photon Emission Computed Tomography with Clinical Outcomes in Patients with Known or Suspected Coronary Artery Disease

Abstract

Single-photon emission computed tomography (SPECT) is a well-established method to evaluate patients with coronary artery disease. Myocardial contrast echocardiography (MCE) is an imaging technique that allows the assessment of myocardial perfusion in real time. Previous research has shown that vasodilator MCE is superior to SPECT for the prediction of hard events. The aim of this study was to investigate the long-term association of SPECT and MCE with clinical outcomes in patients with known or suspected coronary artery disease. Accordingly, 258 patients who underwent MCE and SPECT as part of multicenter studies performed prospectively were followed up for hard events (all-cause mortality and nonfatal myocardial infarction). The mean age was 63.4±5.5years, 186 (72.1%) were men, and 32 (12.4%) had left ventricular systolic dysfunction. We calculated the ratio of the number of abnormal segments (at rest and/or stress) to the total number of segments expressed as MCE and SPECT indices. Over a mean follow-up period of 80.4±6.1months, 46 patients had hard events. MCE and SPECT indices were associated with all-cause mortality on univariate analysis (P=.008 and P=.035, respectively) but only MCE index was independently associated with hard events (hazard ratio, 4.24; 95% CI, 1.27-14.15; P=.019), beyond clinical data and left ventricular function, and independently associated with hard cardiac events (hazard ratio, 4.78; 95% CI, 1.06-21.59; P=.042). MCE but not SPECT showed a long-term association with outcome. These results thus favor the routine use of MCE in the long-term assessment of patients with known or suspected coronary artery disease.