Post-revascularization exercise echo ‘of little benefit’

By Piriya Mahendra

Asymptomatic patients identified as high-risk by exercise echocardiography (ExE) after coronary revascularization and may not necessarily benefit from repeat revascularization, researchers say.

From a health economic standpoint, the appropriateness of such testing must be carefully reviewed, remark Thomas Marwick (Cleveland Clinic, Ohio, USA) and co-authors in the Archives of Internal Medicine.

Exercise electrocardiography was performed in 2105 patients with a mean age of 64 years, of whom 310 (15%) were women. Of these patients, 845 (40%) had a history of myocardial infarction, 1143 (54%) had previously undergone percutaneous coronary intervention (PCI), and 962 (46%) had previously undergone coronary artery bypass graft surgery (CABG).

All patients were followed for a mean period of 5.7 years for cardiac mortality. Late exercise testing (>2 years post-PCI and >5 years post-CABG) was performed in 434 (38%) PCI patients and 435 (45%) CABG patients

Of the 262 (13%) patients with ischemia (defined as new or worsening wall motion abnormality), only 88 (34%) underwent subsequent revascularization.

Patients with ischemia on any post-revascularization ExE had significantly higher mortality than those without ischemia, at 8.0% versus 4.1% (p=0.03). Indeed, multivariate analysis showed that ischemia on ExE was strongly associated with death, at a statistically significant hazard ratio of 2.10 in patients tested early and late.

However, in nested models, clinical and stress test findings, but not echocardiographic features, were significantly associated with all-cause and cardiac mortality.

Subanalysis based on the magnitude of ischemia revealed no difference regarding benefit from revascularization.

Furthermore, looking at patients with specific single cardiac risk factors, including an ejection fraction of less than 50%, or with exercise capacity of less than 6 metabolic equivalents for task (METs), incomplete revascularization, prior heart failure or myocardial infarction, or presence of diabetes mellitus or hypertension failed to identify any subgroups of asymptomatic patients who would benefit from testing and revascularization.

In a related commentary, editorialist Mark Eisenberg (McGuill University, Quebec, Canada) says the current study provides a "compelling argument that routine periodic stress testing in asymptomatic patients following coronary revascularization is of little clinical benefit."

"Until well-supported data become available supporting such a strategy, routine testing in asymptomatic patients is probably not worth the effort," he adds.

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