Absolute quantitation of coronary steal induced by intravenous dipyridamole

OBJECTIVES The study was done to determine whether coronary steal (defined as an absolute decrease in perfusion from resting blood flow) is induced by intravenous (IV) dipyridamole in patients with severe coronary artery dise ase (CAD). BACKGROUND Myocardial ischemia during coronary vasodilation is usually attr ibuted to coronary steal. However, there is limited data on the absolute ma gnitude of coronary steal in humans. METHODS Eighteen patients with multivessel CAD underwent dynamic positron e mission tomography (PET) imaging with (NH3)-N-13 at rest and after infusion of IV dipyridamole. Eight myocardial sectors were analyzed per short axis slice and myocardial blood flow calculated with a two-compartment model in absolute terms. RESULTS Coronary steal occurred in 8 of the 18 patients. In the 8 patients with coronary steal, myocardial blood flow decreased from 90 +/- 18 ml/100 g/min at rest to 68 +/- 27 ml/100 g/min following dipyridamole in the segme nts with steal, and increased from 87 +/- 19 to 138 +/- 16 ml/100 g/min fol lowing dipyridamole in the segments without steal. Significant clinical cor relates of coronary steal were either ST elevation or the combination of ST depression and angina. CONCLUCIONS Coronary vasodilation with IV dipyridamole is associated with s ignificant reductions in blood flow to collateral-dependent myocardium cons istent with coronary steal in about 45% of patients with severe CAD. (J Am Coil Cardiol 2001;37:109-16)(C) 2001 by the American College of Cardiology.