Prognostic Value of Exercise Stress Test and Dobutamine Stress Echo in Patients with Known Coronary Artery Disease

Abstract

The aim of this study was to compare the feasibility of dobutamine stress echocardiography (DSE) and exercise stress test (EST) between patients in different age groups and to evaluate their proportional prognostic value in a population with established coronary artery disease (CAD). The study sample included 323 subjects, subdivided in group 1 (G1), comprising 246 patients aged <75 years, and group 2 (G2), with 77 subjects aged >or=75 years. DSE and EST were performed before enrollment in a cardiac rehabilitation program; for prognostic assessment, end points were all-cause mortality and hard cardiac events (cardiac death or nonfatal myocardial infarction). During DSE, G2 patients showed worse wall motion score index (WMSI), but the test was stopped for complications in a comparable proportion of cases (54 G1 and 19 G2 patients, P = NS). EST was inconclusive in similarly high proportion of patients in both groups (76% in G1 vs. 84% in G2, P = NS); G2 patients reached a significantly lower total workload (6 +/- 1.6 METs in G1 vs. 5 +/- 1.2 METs in G2, P < 0.001). At multivariate analysis, a lower peak exercise capacity (HR 0.566, CI 0.351-0.914, P = 0.020) was associated with higher mortality, while a high-dose WMSI >2 (HR 5.123, CI 1.559-16.833, P = 0.007), viability (HR 3.354, CI 1.162-9.678, P = 0.025), and nonprescription of beta-blockers (HR 0.328, CI 0.114-0.945, P = 0.039) predicted hard cardiac events. In patients with known CAD, EST and DSE maintain a significant prognostic role in terms of peak exercise capacity for EST and of presence of viability and an extensive wall motion abnormalities at peak DSE.