Abnormal exercise echocardiography plus abnormal E/e' ratio at exercise portends worse outcome in patients with dyspnea

Abstract

Background: The role of exercise echocardiography (ExE) for the assessment of patients with dyspnea is promising. We aimed to analyze the clinical characteristics and outcome of patients with this condition referred for ExE.

Methods: A total of 505 patients (66 ± 11 years, 57% women) referred for evaluation of dyspnea were considered. Mitral regurgitation, ratio of early left ventricular inflow wave to early diastolic annulus wave (E/e'), and wall motion abnormalities (WMAs) were measured at rest and at exercise. Considered events were overall mortality, non-fatal myocardial infarction, late revascularization, and admission for heart failure.

Results: Ischemia was observed in 102 patients (20%), whereas WMAs were already present at rest in 55 patients (11%). A percent achieved of predicted metabolic equivalents >100% was found for most of the patients (70%). During a median follow-up of 3.50 years, 66 patients had events (annualized event rate 3.5%). An E/e' value of 13 at post-exercise was the best cut-off value to predict events. After adjustment by clinical and ExE variables, the combination of an abnormal ExE and E/e' values at post-exercise ≥13 was an independent predictor of events (hazard ratio = 3.67, 95% confidence interval = 2.11-6.38, p < 0.001). The worse outcome corresponded to patients with abnormal ExE and raised E/e' values at post-exercise (annualized event rate 17.2%). Patients with normal E/e' values at post-exercise had better outcome irrespective of the ExE results (annualized event rate 2.2% with normal ExE and 2.9% with abnormal ExE), whereas patients with high E/e' values at post-exercise but normal ExE results were at intermediate risk (annualized event rate 5.0%).

Conclusions: Despite favorable ExE results, event rate remains high among patients with dyspnea referred for ExE, which may have a role to predict outcome in this setting. Patients with both raised E/e' values at post-exercise and abnormal ExE results are at the highest event risk.

Keywords: E/e′ values; Exercise echocardiography; Ischemia.