Abstract 14868: Cardiovascular Magnetic Resonance Imaging Based Detection of Chronic Iron Deposition within Non-Reperfused Myocardial Infarctions
Introduction: Chronic iron deposition is known to occur in reperfused hemorrhagic myocardial infarctions (MIs), and could potentially mediate prolonged inflammatory activity and electrical anomalies in the heart.
Hypothesis: We investigated whether stagnant blood in permanently ligated vasculature of non-reperfused MIs could also potentially lead to chronic iron deposition within infarcted territories.
Methods: Canines (n=19) underwent permanent ligation of LAD. CMR exams were performed at 7 days and 4 months post-MI at 3T, and T2* maps and Late Gadolinium Enhancement (LGE) images were acquired. Infarcted territories were detected on LGE images using Mean + 5 Standard Deviations criterion relative to a reference region-of-interest placed in the remote myocardium. Presence of iron within MI territories was detected on T2*-weighted images using Mean - 2 Standard Deviations criterion relative to a reference region-of-interest placed in the remote myocardium. Following the month 4 CMR study, animals were euthanized and ex-vivo histology was performed.
Results: Significant T2* losses were observed within the MI territories in 13 of the 19 canines at 7 days post-MI, and in all canines at 4 months post-MI. Relative to remote myocardium, mean T2* value of the hypointense cores within MI territories was 42.6±10.5% lower on day 7 post-MI (16.7±3.4ms vs. 28.8±3.0ms, p<0.01), and 39.1±12.1% lower at 4 months post-MI (19.3±4.1ms vs. 31.7±1.8ms, p<0.01). Mean infarct and iron volumes (percentage of total LV volume) were 14.7±8.7% and 2.1±1.6% respectively at 7 days post-MI, and 7.2±5.6% and 1.9±1.1% respectively at 4 months post-MI. Ex-vivo TTC staining at 4 months post-MI showed pale brown discoloration within the infarct core, while Perl’s staining confirmed chronic iron deposition within MI territories.
Conclusions: Chronic iron depositions can occur within non-reperfused MIs. The long-term effect of such iron depositions remain to be investigated.
Author Disclosures: A. Kali: None. I. Cokic: None. H.J. Yang: None. R.L. Tang: None. R. Dharmakumar: None.
This research has received full or partial funding support from the American Heart Association.
- © 2014 by American Heart Association, Inc.