Induced ischemia detected by dobutamine stress echocardiography in coronary heart disease patients after myocardial re-vascularization.: Experience in a District General Hospital

Most episodes of myocardial ischemia in patients with known coronary artery disease (CHD) are asymptomatic. Silent myocardial ischemia (SMI) is an important predictor of adverse outcome in patients with proven coronary artery disease. β-blockers are effective in suppressing ischemia, and improve clinical outcome in patients with coronary artery disease. At present, it is common practice to stop treatment with β-blockers in clinically asymptomatic patients after coronary artery bypass graft (CABG) and/or myocardial re-vascularization (PTCA/Stent), although the possible presence of SMI/inducible ischemia after myocardial re-vascularization is not known. We examined 56 asymptomatic CHD patients after coronary artery bypass graft (n=36), percutaneous coronary angioplasty PTCA/stent (n=15), or both (n=5); therapy with β-blockers was stopped in all of them after myocardial revascularization. All these patients underwent a dobutamine stress echocardiography test (DSE test). The DSE test was proposed to these asymptomatic CHD patients to investigate the possible presence of SMI/inducible ischemia after myocardial re-vascularization. All patients had history of myocardial infarction or evidence of mildly impaired left ventricular function at rest as assessed by cardiac catheterization. Abnormal DSE studies occurred in eight of the 56 patients (14%; 95% C.I.: 6–26%). Therapeutic approaches specifically targeted at reducing total ischaemic burden include pharmacologic therapy and myocardial revascularization. On the basis of these data, it can be concluded that asymptomatic CHD patients after myocardial re-vascularization must be re-evaluated to rule out SMI/inducible ischemia that can be treated (e.g. with β-blockers) reducing cardiovascular morbidity and mortality.