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

Abstract

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). 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 >12 hours. 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%, <3 to 3-6: 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). We quantitatively demonstrated that time to p-PTCA treatment significantly influences regional functional recovery of infarcted myocardium at a 4-month follow-up.