Functional evaluation of patients with coronary artery disease: Selection of appropriate pharmacologic agents and imaging modalities

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 dipyrdamole 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 exeicise stress imaging, has important implications regarding patient outcome, patient management, and selection of patients for interventional therapy.