Asessment of Myocardial Reperfusion by Myocardial Contrast Echocardiography and Its Relation to Viable Myocardium

Kang, Duk Hyun; Song, Jae Kwan; Lee, Sang Kon; Kim, Jin Woo; Cheong, Sang Sig; Hong, Myeong Ki; Park, Seong Wook; Kim, You Ho; Park, Chong Hyn; Park, Seung Jung

Abstract

BACKGROUND
As lack of myocardial perfusion was demonstrated on myocardial contrast echocardiography(MCE) despite angiographic documentation of reflow, patency of infarct related artery (IRA) after acute myocardial infarction(AMI) does not guarantee myocardial tissue perfusion. Myocardial enhancement on MCE is associated with myocardial perfusion and microvascular integrity. We are to assess myocardial perfusion immediately after thrombolysis and to correlate myocardial enhancement with functional recovery of postischemic dysfunctional myocardium.
METHODS
MCE was performed by intracoronary injection of hand-agitated Ioxaglate in 17 consecutive AMI patients immediately after thrombolysis. Myocardial enhancement of 37 infarct segment was quantified as corrected peak videointensity(PI) by videodensitometry and the PI ratio of infarct to normal segments was used to assess myocardial reperfusion. Viable myocardium was defined as the presence of functional recovery on follow-up echocardiography.
RESULTS
1) MCE was performed in 37 segments of 17 AMI patient and functional recovery was noted in 28 segments of 12 patients on follow-up echocardiography. 2) Six infarct segments with no reflow on MCE showed severe fixed perfusion defect in thallium scan and no functional recovery in follow-up echocardiography. 3) The peak cardiac enzyme level was significantly higher in patients without functional recovery(p<0.005), but mean PI ratio(p<0.005) and patency of IRA(p<0.05) were significantly higher in patient with functional recovery. Age, sex, time to thrombolysis and stenosis of IRA were not associated with functional recovery. 4) Apical segment(p<0.01), TIMI grade 2 patency(p<0.01) and LAD territory(p<0.05) were significantly associated with nonviable myocardium, and PI ratio(p<0.001) was significantly correlated to viable myocardium. The PI ratio was the most significant predictor of myocardial functional recovery on multiple logistic regression analysis.
CONCLUSION
Myocardial contrast echocardiography immediately after thrombolysis can be used for assessment of myocardial reperfusion, decision of revascularization and prediction of functional recovery.