A substudy of a randomized comparison of medical therapy with or without bypass surgery for ischemic heart disease in patients with LV systolic dysfunction found that overall, substantial viable myocardium evident at baseline imaging studies had no independent bearing on all-cause mortality over five years; and such viability didn’t influence the relative effectiveness of the two treatment strategies, either for all-cause mortality or the secondary end points of CV mortality and CV hospitalization.
The findings, from the Surgical Treatment for Ischemic Heart Failure trial, based on a selected cohort of about half the total trial population, don’t necessarily mean myocardial viability doesn’t have functional implications, observe the substudy authors…
After pointing out the abundant and longstanding but primarily observational support for revascularization guided by viability testing, Dr James C Fang, University Hospitals and Case Medical Center, Cleveland, OH writes in an accompanying editorial that it was “perhaps surprising” that viability didn’t predict a survival benefit from revascularization. The findings, however, “should be interpreted cautiously,” given the substudy’s limitations; for example, patients were selected for viability testing individually at the physicians’ discretion. “However, the substudy’s findings do raise reasonable questions about the most appropriate method to assess myocardial viability,” Fang writes. “The analysis is a strong reminder that in this era of cost-effectiveness, the role of expensive technologies should be accountable to a rigorous study of incremental benefit.”
