Assessment of right ventricular perfusion after right coronary artery occlusion by myocardial contrast echocardiography

Objectives The purpose of this study was to examine the ability of myocardial contrast echocardiography (MCE) to assess right ventricular (RV) perfusion. Background Although MCE can readily assess left ventricular perfusion abnormalities, there are no data regarding the ability to assess RV perfusion abnormalities. Methods The right coronary artery (RCA) was occluded in 10 open-chest dogs. Myocardial contrast echocardiography was performed with 0.27 g/min Levovist infusion by harmonic power Doppler with electrocardiographically gated intermittent triggered imaging at pulsing intervals ranging from 1:1 to 1:20 at baseline and 90 min after RCA occlusion. Video-intensity of the RV wall was plotted against pulsing intervals and was fitted to an exponential function: Y = A(1-exp−bt), where A is the plateau video-intensity and b is the rate of video-intensity rise. Myocardial contrast echocardiography and microsphere-derived myocardial blood flow (MBF) measurements were performed at baseline and 90 min after RCA occlusion. Results Because the severity of RV perfusion abnormalities assessed by MBF varied during RCA occlusion, diverse grades of patchy opacification defects were observed by MCE. The RV wall thickness decreased, and the RV dimension increased, after RCA occlusion in each dog. The correlation of occlusion to baseline MBF ratios in the RV wall was closer to the ratio of b (r = 0.897, P = 0.0004) than A (r = 0.767, P = 0.0097) and was the closest to the ratio of Axb (r = 0.935, p < 0.0001). Conclusions The RCA occlusion is manifested by RV wall thinning and dilation as well as by perfusion abnormalities consisting of patchy opacification defects by MCE. Myocardial contrast echocardiography–derived refilling parameters can be applied to assess RV perfusion abnormalities produced by RCA occlusion.