SIMULTANEOUS ASSESSMENT OF MYOCARDIAL PERFUSION AND LEFT-VENTRICULAR FUNCTION DURING TRANSIENT CORONARY-OCCLUSION

Objectives. We used technetium-99m sestamibi imaging to evaluate the m agnitude of changes in left ventricular function and perfusion and to investigate their interdependence during transient coronary occlusion. Background. Transient coronary occlusion during coronary angioplasty provides a unique opportunity for examining the effects of acute myoca rdial ischemia on left ventricular function and perfusion. Methods. Th irty five patients with normal left ventricular function underwent fir st-pass radionuclide angiography with technetium-99m sestamibi using a multicrystal gamma camera during balloon occlusion of a coronary arte ry. Single-photon tomography was performed 2.1 +/- 1.7 h later. Subseq uently, all scans were repeated at rest. Results. The mean size +/- SD of the perfusion defect during coronary occlusion was 23 +/- 18%, wit h significantly Larger defects observed for occlusions of the left ant erior descending coronary artery (39 +/- 20%) than for occlusions of t he Left circumflex (15 +/- 11%) or right (15 +/- 9%) coronary artery ( p < 0.05). The mean change in ejection fraction from recovery to occlu sion was -17 +/- 17% and was significantly larger for left anterior de scending (-26 +/- 21%) and left circumflex (-15 +/- 11%) than for righ t (-8 +/- 10%) coronary artery occlusions (p < 0.05). For the entire g roup, ejection fraction during occlusion correlated significantly with perfusion defect size (r = 0.63, p = 0.0004), whereas the extent of i schemic myocardium correlated with the decrease in ejection fraction ( r = 0.69, p = 0.0001), The defects present during occlusion reversed w ithin a few hours. Conclusions. Changes in left ventricular function a nd perfusion develop pari passu during coronary occlusion and are more severe when the left anterior descending artery is occluded. Although a significant correlation exists between the extent of the perfusion defect and the severity of the decrease in ejection fraction, there is a substantial individual variation,vith respect to changes in both my ocardial perfusion and ventricular function during acute coronary occl usion.