DOBUTAMINE VERSUS DIPYRIDAMOLE-MAGNETIC RESONANCE IMAGING - SAFETY AND SENSITIVITY FOR THE DIAGNOSIS OF CORONARY-ARTERY STENOSES

Safety and sensitivity of gradient-echo magnetic resonance imaging (MRI) for the identification of significant coronary artery stenoses using pharmacologic stress testing was assessed in 61 patients with greater-than-or-equal-to 70 % stenosis of a major coronary artery and a normal left ventricle. After MRI at rest 28 patients underwent dobutamine-MRI during steady-state dobutamine infusion (5, 10, 15 and 20 mug/kg/min) and 33 patients had dipyridamole-MRI after high-dose dipyridamole infusion (0.75 mg/kg over 10 min). All patients additionally performed standard ECG exercise stress testing (EST). Segmental wall motion analysis was performed in basal and midventricular short axis tomograms by two observers. A segment was graded pathologic if transient dobutamine or dipyridamole induced wall motion abnormalities could be detected. For comparison to coronary angiography findings, each segment was assigned to one of the coronary artery perfusion territories. There were no serious side-effects during dobutamine and dipyridamole infusion leading to termination of the study protocol. Peak double product during dobutamine infusion was significantly higher (p < 0.001) than after dipyridamole infusion (18.493 +/- 4.311 versus 12.799 +/- 2.694 mm Hg/min). Overall sensitivity of dobutamine and dipyridamole-MRI for coronary artery disease (CAD) was 85 % and 84 %. Regional asynergy by dobutamine and dipyridamole-MRI was observed in 73 % versus 79 % patients with single- and 100 % versus 92 % with multi-vessel disease. Individual coronary artery stenoses were correctly identified by segmental wall motion abnormalities in 87 % versus 81 % for left anterior descending, 62 % versus 86 % for left circumflex and 78 % versus 92 % for right coronary artery stenoses. In conclusion, dobutamine and dipyridamole-MRI are well tolerated and safe non-exercise dependent tests for detection and localization of hemodynamically significant coronary artery stenoses with a similar diagnostic accuracy but with a better control of stress intensity and duration provided by dobutamine.