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Arbutamine, a new potent non-selective β-adrenoceptor agonist with mild α1-sympathomimetic activity, has been developed specifically for pharmacological stress testing. The drug acts like physical exercise, increasing both heart rate and myocardial contractility. Sensitivity, specificity and accuracy in detecting significant stenotic coronary artery disease are 76%, 96%, and 82%, respectively, agian similar to those of exercise echocardiography.The drug is delivered by a computerized drug delivery and monitoring device (GenESA) which adjusts the infusion rate according to the patient's heart rate data feedback. The drug is generally well tolerated and has an acceptable safety profile.This article describes recent clinical experience with arbutamine and presents preliminary results of a multicentre multinational study which evaluates the clinical utility and safety of the GenESA system in diagnosing coronary artery disease. [ABSTRACT FROM PUBLISHER]

Arbutamine (Gensia, Inc., San Diego, CA) is a newly-developed sympathomimetic agent specifically designed forcardiovascular stress testing. It has been successfully used for the detection of coronary artery disease in conjunction with electrocardiography, echocardiographic and radionuclide techniques. Arbutamine increases heart rate and contractility, thus provoking ischaemia in a manner analogous to that of physical exercise. Ischaemia becomes manifest by reproduction of typical angina, diagnostic electro cardiographic changes, the development of a wall motion abnormality on two-dimensional echocardiography or of a perfusion defect on thallium scintigraphy. Thus far in clinical trials it has shown an acceptable side-effect profile and a level of diagnostic accuracy for the detection of patients with coronary disease equivalent to or exceeding that seen with physical exercise. [ABSTRACT FROM PUBLISHER]

Exercise myocardial perfusion imaging and exercise echocardiography have been applied widely for diagnosis and risk stratification of patients with known or suspected coronary artery disease. The accuracy of these evaluations depends upon the ability of the patient to achieve maximal exercise (>85% of age-predicted maximal heart rate). In patients unable to exercise or with a limited capacity to exercise maximally, pharmacologic stress imaging is a safe and effective alternative to exercise stress imaging. Pharmacologic stress is also indicated in patients with resting or exercise-induced left bundle branch block. Vasodilator stress with dipyridamole or adenosine, as well as catecholamine stimulation with dobutamine or preliminarily with arbutamine, provides diagnostic and prognostic information that appears to be equivalent to that achieved with exercise imaging. In addition, low dose catecholamine infusion during echocardiography to assess inotropic reserve is valuable in identifying viable myocardium in patients with left ventricular dysfunction and appears to assess viability with an accuracy that approaches that of nuclear cardiology methods. Hence, pharmacologic stress imaging, like exercise stress imaging, has important implications regarding patient outcome, patient management, and selection of patients for interventional therapy. [ABSTRACT FROM PUBLISHER]

Background: There is a paucity of data comparing the relative merits of inotropic and vasodilator stress Tc-99m sestamibi single-photon emission computed tomography (SPECT) for the detection of coronary artery disease and reversible ischemia.Methods and Results: Twenty-seven patients referred for diagnostic coronary arteriography underwent separate day dipyridamole and arbutamine Tc-99m sestamibi SPECT imaging with simultaneous two-dimensional echocardiography. The sensitivity of arbutamine and dipyridamole Tc-99m sestamibi for the detection of coronary artery disease was 100% (21 of 21) and 90% (19 of 21), respectively, with a specificity of 66% (4 of 6) for both. Coronary artery disease was detected in all six patients with single vessel disease by both stress modalities. The sensitivity for prediction of multivessel disease was 66% (10 of 15) for arbutamine and 46% (7 of 15) for dipyridamole stress. Arbutamine stress induced a greater extent and severity of perfusion abnormality at peak stress (peak perfusion score 25 +/- 6.2 and 21 +/- 5.9 for arbutamine and dipyridamole, respectively, p = 0.001) and reversible perfusion defects (difference between peak stress and rest scores 8.8 +/- 5.5 and 5.2 +/- 4.4 for arbutamine and dipyridamole, respectively, p = 0.001). Furthermore a significantly higher percentage of reversible defects induced by arbutamine stress was associated with wall thickening abnormality on simultaneous echocardiography, which is a more specific marker of myocardial ischemia (88% and 24% for arbutamine and dipyridamole, respectively, p = 0.002).Conclusion: Inotropic stress may be superior to vasodilators for the determination of the extent and severity of myocardial involvement and reversible ischemia by Tc-99m sestamibi SPECT. [ABSTRACT FROM AUTHOR]

Background: Arbutamine is a new synthetic catecholamine developed specifically for pharmacologic stress testing.Methods and Results: We investigated 39 patients undergoing coronary arteriography to compare arbutamine stress (99m)Tc-labeled sestamibi single-photon emission computed tomographic imaging and echocardiography for detection of the extent and severity of coronary artery disease and inducible ischemia. Rest and stress studies were analyzed blindly according to a 12-segment left ventricular model for both techniques. Each segment was graded according to severity of wall thickening abnormality and perfusion defect (1 = normal to 4 = severe). Total perfusion defect and wall thickening scores were calculated at peak stress and the difference in scores between stress and rest (delta perfusion defect; delta wall thickening) were used as indexes of inducible ischemia. Twenty-one patients had multivessel disease, nine had single-vessel disease, and nine had normal coronary arteries. Diagnostic accuracies for the detection of coronary artery disease for single-photon emission computed tomographic imaging and echocardiography were 95% and 92%, respectively. Extent and severity of coronary artery disease indicated by a peak stress perfusion defect score of 26 +/- 6.4 and wall thickening score of 25.1 +/- 8.4 were similar, and there was no significant difference in the delta perfusion defect and delta wall thickening scores of 8.7 +/- 5.5 and 10.4 +/- 7.1, respectively. Segmental concordance rates for the detection of coronary artery disease and inducible ischemia were 74% (K = 0.47; confidence interval 0.39 to 0.55) and 74% (kappa = 0.42; confidence interval 0.34 to 0.51), respectively. Regional concordance for coronary artery disease was 84% (kappa = 0.68; confidence interval 0.51 to 0.84). Where discordance was present, there was a greater prevalence of perfusion abnormality compared with wall thickening abnormality.Conclusion: Arbutamine stress single-photon emission computed tomographic imaging and echocardiography provide largely equivalent and accurate pathophysiologic information for the evaluation of coronary artery disease and inducible ischemia. [ABSTRACT FROM AUTHOR]