BOSTON — For acute heart failure patients with neither a history of coronary disease nor evidence of acute MI, myocardial contrast echocardiography can distinguish ischemic from nonischemic etiology, a study has shown.
The ability to identify underlying coronary artery disease in such patients has therapeutic and prognostic implications, reported Rajesh Janardhanan, M.D., in a poster presentation at the annual meeting of the American Society of Echocardiography.
A noninvasive bedside technique for evaluating acute coronary syndromes, myocardial contrast echocardiography (MCE) provides a simultaneous assessment of regional wall motion and myocardial perfusion using microbubble contrast agents.
To assess the sensitivity and specificity of the imaging tool in the evaluation of acute heart failure, Dr. Janardhanan of Brigham and Women's Hospital in Boston, and investigators at Northwick Park Hospital in Harrow, England, reviewed the imaging results from 52 consecutive patients with acute heart failure with no prior history of coronary artery disease (CAD) and no clinical evidence of acute MI on hospital admission.
All the patients in the study underwent echocardiography and MCE at rest and following dipyridamole stress. Additionally, all patients underwent coronary arteriography prior to hospital discharge. On coronary arteriography, 22 of the 52 patients had evidence of CAD, defined as more than 50% luminal diameter narrowing, Dr. Janardhanan said.
The sensitivity and specificity of MCE for detecting CAD in the 22 patients were 82% and 97%, respectively, with a positive predictive value of 95% and a negative predictive value of 88%. Among the various markers of CAD, including MCE, clinical variables, ECG, biochemical measures, and resting echocardiographic results, MCE “was the only [statistically significant] independent predictor of CAD,” said Dr. Janardhanan.
Both myocardial blood flow reserve and myocardial blood velocity reserve decreased relative to increasing CAD severity, suggesting quantitative MCE data may be an effective tool for stratifying risk in patients with acute heart failure, Dr. Janardhanan concluded.