Quantification of regional functional improvement of infarcted myocardium after primary PTCA by contrast-enhanced magnetic resonance imaging

Abstract

Purpose: To assess with cardiac magnetic resonance imaging (CMR) the relationship between treatment delay and improvement of regional left ventricular function after primary percutaneous transluminal coronary angioplasty (p-PTCA) for acute myocardial infarction (AMI). Materials and Methods: We performed cine- and late enhancement (LE) CMR in 40 patients with first AMI after restoring TIMI 3 flow with p-PTCA and at a follow-up 4 months later. Infarcted segments were determined from LE images. Regional left ventricular function was quantified from cine-CMR images. Segmentation followed the American Heart Association 17-segments model. Patients were divided into groups with delay <3 hours, 3-6 hours, 6-12 hours, and a delay > hours. Results: Segmental wall thickening (SWT) significantly iproved only in segments reperfused within 6 hours (P < 0.001). Follow-up SWT was significantly higher if segments were reperfused early (<3 hours: 74 ± 4%, 3-6 hours: 57 ± 4%, 6-12 hours: 48 ± 7%, <3to3-6: P < 0.003, and <3 to 6-12 hours: P < 0.001). The extent of improvement was greater if delay was <3 hours compared to segments with a delay of >3 hours (< 3 hours: + 21 ± 3%, 3-6 hours: +8 ± 4%, 6-12 hours: +6 ± 3%; < 3 hours to 3-6 hours, and 6 -12 h, P < 0.02). Conclusion: We quantitatively demonstrated that time to p-PTCA treatment significantly influences regional functional recovery of infarcted myocardium at a 4-month follow-up. © 2009 Wiley-Liss, Inc.