Arbutamine echocardiography: Efficacy and safety of a new pharmacologic stress agent to induce myocardial ischemia and detect coronary artery disease

Objectives. This study sought to determine the efficacy and safety of arbutamine echocardiography in inducing myocardial ischemia and detecting coronary artery disease. Background. Exercise and pharmacologic stress echocardiography are clinically accepted techniques for detecting coronary artery disease. Arbutamine is a new synthetic beta-adrenoceptor agonist developed specifically as a stress agent. Arbutamine is delivered by a new computerized drug delivery device that adjusts the rate of drug infusion according to the patient's heart rate response during stress testing. Methods. The sensitivity of arbutamine echocardiography was determined in 143 patients who had coronary artery disease documented by coronary angiography. A subset of these patients (n = 114) also underwent exercise echocardiography. The specificity, or normalcy, of arbutamine echocardiography was determined in 54 patients considered to have a low likelihood of coronary artery disease. Results. Among those patients who had both stress test results, the incidence of inducing myocardial ischemia (new or worsening wall motion abnormalities) was 79% (95% confidence interval [ci]69% to 86%, n = 98) for arbutamine and 77% (95% CI 67% to 85%, n = 98) for exercise echocardiography. The sensitivity of detecting coronary artery disease (ischemia or rest wall motion abnormality) was 87% (95% CI 79% to 93%, n = 101) for arbutamine and 83% (95% CI 74% to 90%, n = 101) for exercise echocardiography. The specificity (normalcy) of arbutamine echocardiography was 96% (95% CI 87% to 100%, n = 52). Arbutamine was well tolerated, and there were no serious adverse events. Conclusions. Arbutamine echocardiography is an effective and safe pharmacologic stress test technique for diagnosing or excluding the presence of coronary artery disease. The ability of arbutamine stress to induce myocardial ischemia, detectable by echocardiography, was comparable to that for exercise.