Abstract 363: Relation Between Left Ventricular Fibrosis Assessed by Integrated Backscatter and Left Ventricular Remodeling After Acute Myocardial Infarction
Background Left ventricular (LV) remodeling after acute myocardial infarction (AMI) is associated with a poor outcome. The development of LV remodeling is related to scar formation at the site of infarction and the development of interstitial fibrosis in the non-infarcted myocardium. Calibrated integrated backscatter (CIBS) defines the physical state of myocardial tissue and is a useful non-invasive method for the assessment of myocardial fibrosis. The purpose of the present study was to evaluate the amount of fibrosis in the non-infarcted myocardium at baseline and 3 months follow-up with CIBS. In addition, the relation between fibrosis and the development of LV remodeling at 12 months follow-up was assessed.
Methods Patients admitted with first AMI treated with primary percutaneous coronary intervention were evaluated. 2D echocardiography was performed at baseline within 48 hours after admission and during follow-up at 3 and 12 months. Baseline echocardiography was used to assess LV function with traditional parameters. CIBS was assessed at the remote (non-infarcted) myocardium at baseline and 3 months follow-up. LV remodeling at 12 months follow-up was defined as an increase in LV end-systolic volume of at least 15%.
Results A total of 320 patients were evaluated. Mean age was 59±11 years and most patients were men (249 patients, 78%). Mean LV ejection fraction was 46±8%. Mean CIBS was −21.3±4.8 dB at baseline and −23.8±4.8 dB at 3 months follow-up. Patients showing LV remodeling at 12 months follow-up (48 patients, 15%) had comparable baseline CIBS. However, at 3 months follow-up, patients with LV remodeling demonstrated significantly lower CIBS compared to patients without LV remodeling (−20.4±4.6 dB vs. −24.4±4.7 dB, p <0.0001). Multivariate analysis demonstrated that the left anterior descending coronary artery as culprit vessel (HR 2.8, 95% CI 1.3 – 6.1, p <0.05), peak cardiac troponin T level (HR 1.1, 95% CI 1.0 – 1.1, p <0.05) and CIBS at 3 months (HR 1.2, 95% CI 1.1 – 1.3, p <0.0001) were independent predictors of LV remodeling at 12 months follow-up.
Conclusion CIBS of the non-infarcted myocardium is a useful noninvasive method to predict LV remodeling in patients after AMI.