%I American Heart Association
%T Chronic Manifestation of Post-Reperfusion Intramyocardial Hemorrhage as Regional Iron Deposition: A Cardiovascular MR Study with Ex-vivo Validation
%X Background?Intramyocardial hemorrhage frequently accompanies large reperfused myocardial infarctions. However, its influence on the make-up and the ensuing effect on the infarcted tissue during the chronic phase remain unexplored.

Methods and Results?Patients (n = 15; 3 women), recruited after successful PCI for first ST-elevation myocardial infarction, underwent Cardiovascular Magnetic Resonance (CMR) imaging on day 3 and month 6 post-PCI. Patients with hemorrhagic (Hemo+) infarctions, as determined by T2* CMR on day 3 (n = 11), showed persistent T2* losses co-localized with scar tissue on the follow-up scans, suggesting chronic iron deposition. T2* values of Hemo+ territories were significantly higher than non-hemorrhagic (Hemo-) and remote territories (p<0.001); however, T2* values of non-hemorrhagic (Hemo-) and remote territories were not different (p=0.51. Canines (n = 20), subjected to ischemia-reperfusion (I/R) injury (n = 14), underwent CMR on days 3 and 56 post I/R injury. Similarly, sham-operated animals (Shams; n = 3) were imaged using CMR at similar time points. Subsequently, hearts were explanted, imaged ex-vivo, and samples of Hemo+, Hemo-, remote and Sham myocardium were isolated and stained. The extent of iron deposition ([Fe]) within each sample was measured using mass spectrometry. Hemo+ infarcts showed significant T2* losses compared to the other (control) groups (p<0.001), and Perl's stain confirmed localized iron deposition. Mean [Fe] of Hemo+ was nearly an order of magnitude greater than the control groups (p<0.001), but no significant differences were observed among the control groups. A strong linear relationship was observed between log(T2*) and -log([Fe]) (R2=0.7; p<0.001). The monoclonal antibody Mac387 stains, along with Perl's stains, showed preferential localization of newly recruited macrophages at the site of chronic iron deposition.

Conclusions?Hemorrhagic myocardial infarction can lead to iron depositions within the infarct zones, which can be a source of prolonged inflammatory burden in chronic phase of myocardial infarction. 
%L eprints1509
%A Avinash Kali
%A Andreas Kumar
%A Ivan Cokic
%A Richard Tang
%A Sotirios A. Tsaftaris
%A Matthias G Friedrich
%A Rohan Dharmakumar
%R 10.1161/CIRCIMAGING.112.000133
%K acute myocardial infarction; cardiac magnetic resonance imaging; hemorrhage; inflammation
%D 2013
%O Published online before print February 12, 2013
%J Circulation: Cardiovascular Imaging