Stress Echocardiography Audit: Experience of a Tertiary Care Center

Abstract

Background: Stress echocardiography is a very useful diagnostic and prognostic test in the evaluation of significant coronary artery disease (CAD) causing inducible myocardial ischemia. Stress echocardiography has higher sensitivity and specificity as compared to exercise stress electrocardiography, and therefore, the guidelines recommend opting for the former modality over the latter. There are data suggesting that the incidence of major cardiac events is <1% within 12 months of a negative stress echocardiogram showing no reversible ischemia. The present audit was performed to assess the predictive accuracy of stress echocardiography at our center for major cardiac events during the first year of the test. Methods: Data for all patients referred for stress echocardiography between March 10, 2015 and December 31, 2018 were captured. All patients were contacted after 1 year to evaluate for any cardiac event (cardiac death, nonfatal myocardial infarction, need for revascularization or hospital admission related to acute coronary syndrome, and/or heart failure). Analysis was performed using the standard statistical definitions. Results: Baseline information was available for 1205 patients (mean age 59 years, 60% males). Of these, 416 (34.4%) had documented CAD; 223 (18.4%) underwent stress echocardiography for chest pain evaluation, whereas 273 (22.6%) underwent the test for preoperative assessment before a noncardiac surgery. Dobutamine stress echocardiography was the modality in 1145 (95.0%) patients; ultrasound contrast was used in 1154 (95.8%) patients. One-year event rates were available for 1024 patients. Stress echocardiography was normal in 1009 (98.5%) of these patients, eight of whom had a cardiac event during the subsequent year, yielding a negative predictive value (NPV) of 99.2%. The test was abnormal in 15 (1.5%) patients, but two of them were later found to have normal coronary arteries, yielding a positive predictive value (PPV) of 86.7%. The NPV and PPV were thus both at par or even higher than most other centers. The incidence of complications during stress echocardiography was extremely low. Conclusions: This audit shows that stress echocardiography at our center has an excellent safety as well as accuracy for predicting major adverse cardiac events during the subsequent year. Stress echocardiography could thus obviate the need for coronary angiogram and even revascularization in many patients. Our findings also reinforce the value of stress echocardiography as a greatly useful preoperative test for cardiac fitness in patients undergoing a major noncardiac surgery.