Cardiac Viability Tests Are Not a Good Gauge for Best Treatment

Of these, 601 participants at 99 study sites in 22 countries had assessments for myocardial viability. Of these, 298 were randomized to medical therapy including coronary artery bypass graft (CABG) and 303 were selected for medical therapy alone. The results showed that a total of 178 (37%) of the 487 patients with viable myocardium and 58 (51%) of the 114 patients without viable myocardium died; however, the association with mortality was not significant after adjustment for other baseline variables. The study was published in the April 28, 2011, issue of the New England Journal of Medicine (NEJM).

"The data suggests that in the presence of coronary artery disease, studies of myocardial viability do not direct practitioners in the need for coronary artery bypass," said study author Philip Binkley, MD, a cardiologist at OSUMC. "The presence of significant coronary artery disease rather than evidence that the heart muscle will improve with bypass surgery should dictate the treatment."

"The study tells us that noninvasive assessment of myocardial viability may guide patient management. Multiple imaging techniques have been developed to assess viable and nonviable myocardium by evaluating perfusion, cell membrane integrity, mitochondria, glucose metabolism, scar tissue, and contractile reserve," added Dr. Brinkley.

Tests for myocardial viability attempt to identify areas of heart muscle that are "living" but have a reduction of blood flow. Tests used in the study were the single photon emission tomography and dobutamine echocardiography. The study did not include newer methodologies, such as magnetic resonance imaging (MRI), which may be more accurate in selecting myocardial viability.

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