Dobutamine versus dipyridamole for inducing reversible perfusion defects in chronic multivessel coronary artery stenosis

ObjectivesWe hypothesized that, although the effects of dipyridamole and dobutamine on myocardial blood volume (MBV) and mean microbubble velocity (VEL) are different, the magnitude of perfusion deficit during both forms of stress is the same because both drugs unmask abnormal myocardial blood flow (MBF) reserve.BackgroundBoth dipyridamole and dobutamine are used clinically as pharmacologic stress agents to induce reversible perfusion defects in patients with chronic coronary artery disease (CAD), but the basis for doing so for dobutamine is not clear.MethodsEleven chronically instrumented closed-chest dogs with multivessel coronary stenosis were studied. Hemodynamics, radiolabeled microsphere-derived MBF, and myocardial contrast echocardiography (MCE)-derived myocardial perfusion were measured at rest, after dipyridamole infusion (0.56 mg·kg−1), and at peak dobutamine dose (either 30 or 40 μg·kg−1·min−1). Abnormal beds were defined as those demonstrating an MBF reserve