Quantification of Ischemia As a Prognostic Mandate for Coronary Revascularization in Asymptomatic Patients: How Much Is Enough?

The aim of this study was to investigate whether asymptomatic patients with known coronary artery disease and demonstrable myocardial ischemia warrant revascularization on prognostic grounds. A Medline and PubMed search was performed, including 7 trials with data discussed and concise reviews of prominent articles in the field. The magnitude of inducible ischemia in those with known coronary disease correlates closely with poor cardiovascular outcomes in terms of death, myocardial infarction, hospitalization, and revascularization. Patients with ≥10% inducible ischemia experience a survival advantage when revascularized with a reduction in mortality of greater than 50% regardless of symptoms (P < 0.00001). Evidence also suggests that left ventricular function remains preserved in those who are revascularized when compared with medical therapy alone; left ventricular ejection fraction 53.9% versus 48.8% (P < 0.001). Silent ischemia is a useful prognostic marker in those with known coronary disease. It is recommended that asymptomatic patients with known coronary disease be revascularized on prognostic grounds if ≥10% ischemia can be demonstrated on nuclear or myocardial perfusion scan, ≥3 segments of regional wall motion abnormality on stress echocardiography/cardiac magnetic resonance imaging, or ≥2 segments with perfusion deficits on stress perfusion cardiac magnetic resonance imaging.