Vai trò cộng hưởng từ ngấm thuốc muộn trong dự báo khả năng phục hồi chức năng tim ở bệnh nhân nhồi máu cơ tim cấp được can thiệp tái thông động mạch vành thì đầu

Role of delayed contrast-enhanced magnetic resonance Imaging to predict cardiacfunctional improvement after primary percutaneous coronary intervention for patients with acute myocardial infarction

SUMMARY

Objective: To access the transmural extent of hyperenhancement and infarct size at Delayed Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) on relating toleft ventricular (LV) functional improvement in reperfused myocardial infarction (MI) and to compare theLV morphology and function on MRI afterprimary percutanous coronary revascularization.

Materialand Methods: Cine sequenceand Delayed Contrast- Enhanced MRIwere underwent in period of 9 days after percutanous coronary revascularization on29 patients suffering fromAcute MI at Bach Mai Hospital. Long term follow-up cardiac MRI was done to compare the change in LV morphology and function, infarct size. Myocardial wall thickening and left ventricular volumes were quantified on cine-images, and the transmural extent of infarction (TEI), infarct size was doned on delayed-enhancement images. Remodeling was defined as an increase in LV end-diastolic volume index of 20% or higher at follow up.

Results: A decrease in myocardial mass (104,9 ± 23,4 to 96,1 ± 25,6 gram; p<0,05), mean SWT score (16,5 ± 4,9 to 14,6 ± 6,1; p<0,001) and increase the mean ejection fraction (45,7 ± 6,9 to 48,8 ± 9,2%; mean 3,2%; p<0,05), whereas mean end-diastolic volume(107,1 ± 23,8to131,7 ± 37,8 ml; p<0,0001) and mean end-systolic volume(58,5 ± 16,3 to 69,3 ± 29,3 ml, p<0,05) did not decrease. Segmental wall thickening did not change (42,6 ± 23,6to 43,3 ± 24,1%; p>0,5). The infarct size at DCE-MRI was related to LVEDVI (r=0,643, p<0,0001). Infarct size of 29% or more of LV area predicted remodeling with high sensitivity (100%) and specificity (89%). The extent of segments that was dysfunctional but viable was related to improvement in ejection fraction(r=0,56; p=0,002). Segmental wall thickening improved significantly in segments with<25% TEI(35 ± 7 to48 ± 7%, p<0,0001), tended to improve in segments with 25% to 75% TEI (32± 10to38 ± 11%, p<0,001), whereas segments with>75% TEI did not improve (22 ± 15to20 ± 14%, p<0,05).

Conclusion:In patients with recent reperfused MI, functional improvement predicted by delayed contrast-enhanced Magnetic Resonance Imaging.

Key words: Cardiac Magnetic Resonace Imaging, delayed enhancement MRI, late gadolinium, Acute myocardial infarction, transmural extent of infarction (TEI), infarct size.