ABSTRACT

BACKGROUND - Exercise echocardiography (EE) is a valuable noninvasive method for diagnostic and prognostic assessment of ischemic cardiac disease. The prognostic value of a negative EE test is well known overall, but its role in patients who undergo percutaneous coronary intervention remains poorly validated. The aim of this study was to ascertain the prognostic value of treadmill EE and to determine predictors of cardiac events in this population, with an emphasis on nonpositive (negative or inconclusive) test results.

METHODS - A retrospective single-center study was performed. It included 516 patients (83% man; mean age, 62 ± 9 years) previously subjected to percutaneous coronary intervention who underwent treadmill EE between 2008 and 2017. Demographic, clinical, echocardiographic, and angiographic data were collected. The occurrence of cardiac events (cardiac death, acute coronary syndrome, or coronary revascularization) during follow-up was investigated. A multivariate Cox regression analysis was used to evaluate predictors of cardiac events. The Kaplan-Meier method was used to evaluate event-free survival rates.

RESULTS - The results of EE were negative for myocardial ischemia in 245 patients (47.5%), inconclusive in 144 (27.9%), and positive in 127 (24.6%). During a mean follow-up period of 40 ± 34 months, cardiac events occurred in 152 patients (29.5%). The positive and negative predictive values of EE were 81.6% and 85.3%, respectively. The sensitivity of the exercise test was 73.9%, with specificity of 90.1%. Predictors of cardiac events were typical angina (hazard ratio [HR], 1.95; 95% CI, 1.16–3.27; P = .011), a positive ischemic response detected by electrocardiographic monitoring during EE (HR, 2.01; 95% CI, 1.21–3.34; P = .007), and the test result (inconclusive result: HR, 1.06; 95% CI, 0.51–2.19; P = .878; positive result: HR, 4.35; 95% CI, 2.42–7.80; P < .001). Patients with inconclusive (log-rank P = .038) and positive (log-rank P < .001) results had significantly more cardiac events during follow-up than those with negative EE test results. Focusing on those patients with nonpositive results, cardiac event–free survival rates at 1, 3, and 5 years were 96.6 ± 0.9%, 88.3 ± 1.9%, and 79.5 ± 2.6%, respectively. In this subpopulation, an inconclusive test result (HR, 1.67; 95% CI, 1.03–2.70; P = .039), more extensive coronary artery disease (two vessels: HR, 1.37; 95% CI, 0.75–2.30; P = .304; three vessels: HR, 2.59; 95% CI, 1.38–4.87; P = .003), and arterial hypertension (HR, 2.07; 95% CI, 1.10–3.91; P = .025) were significantly associated with the occurrence of cardiac events.

CONCLUSION - Patients with known coronary disease with negative results on EE are at low risk for hard events. Patients with inconclusive results are at higher risk for cardiac events than those with negative results. The detection of patients with low-risk results on EE should decrease the number of unnecessary repeat invasive coronary angiographic examinations.