Abstract 963: Different Patterns of LV Dilation after Coronary Reperfusion: Results from the Acute Myocardial Infarction Contrast Imaging (A.M.I.C.I) Multicenter Study
Background: Left ventricular remodelling (LVR) is an important predictor of mortality after acute myocardial infarction (AMI). However during the first months after AMI different changes of end-diastolic volumes (EDV) may be observed:
EDV reduction (reverse LVR),
no changes in EDV,
mild left ventricle enlargement (mLVR) and,
significant left ventricle enlargement (LVR).
Objectives: Main determinants of different patterns of LV dilation after AMI are still under discussion. The aim of this study was to assess the role of microvascular damage in the genesis of these different LV volumes behaviours.
Method: A total of 110 patients with first successfully reperfused STEMI were enrolled in the Acute Myocardial Infarction Contrast Imaging (A.M.I.C.I) multicenter study. Microvascular perfusion damage was evaluated by intravenous myocardial contrast echocardiography (MCE) using continuous infusion of Sonovue (Bracco SpA) in real-time imaging. The endocardial length of contrast defect (CDL%) on day 1 after reperfusion (T1) was calculated. The extent of wall motion abnormalities (WMA%), LV end-diastolic volumes (EDV), and ejection fraction (EF%) on T1 and at follow-up (T2) were also calculated.
Results: At follow-up, LVR (EDV >20%) occurred in 24 % of our patient while 32% had reverse LVR (ΔEDV 5 % < 20%). At first control after reperfusion (T1), CDL% and WMA% were significantly lower and EF% was significantly higher in patients with reverse LVR and in those with stationary EDV (p<.0001) as compared to patients with mild or significant LVR. At follow-up, WMA% and EF% improved in patients with reverse LVR, stable EDV and middle LVR, while didn’t change in patients with significant LVR. Multivariate analysis, including all clinical, echocardiographic and angiographic variables assessed at T1, showed that CDL% and EF% were the only independent predictors of LVR.
Conclusion: Different patterns of LV dilation after AMI are strictly correlated to the extension of microvascular damage soon after reperfusion.