The Contribution of Intramyocardial Hemorrhage to the “No-Reflow Phenomenon”: A Study Performed by Cardiac Magnetic Resonance


  • Conflict of interest: None of the authors has financial associations or other involvements that might pose a conflict of interest in connection with the article.

Address for correspondence and reprint requests: Martina Perazzolo Marra, M.D., Division of Cardiology, Department of Cardiac, Thoracic, and Vascular Sciences, University of Padua, Padua, Italy, Policlinico Universitario, Via Giustiniani, 2, 25128 Padova, Italy. Fax: +39 049 8761764; E-mail:


Background: Percutaneous coronary intervention (PCI) in acute myocardial infarction (AMI) is sometimes complicated by microvascular damage and hemorrhage. Hemoglobin degradation products have magnetic susceptibility effects which help in detecting hemorrhagic AMI by T2-weighted cardiac magnetic resonance (CMR) images. Objectives: To investigate the possibility to detect intramyocardial hemorrhage after AMI and to assess its contribution to the delayed hypoenhanced core on late gadolinium enhancement (LGE) CMR, a feature traditionally referred to as microvascular obstruction. Methods: Consecutive patients with AMI who underwent PCI and CMR were investigated. Hypointense zones T2-weighted images were labelled as “hemorrhagic” AMI. Areas of late hypoenhancement on LGE CMR were considered as regions of persistent microvascular damage (PMD). Only transmural AMI were considered. Results: A total number of 108 transmural AMI patients were eventually enrolled and divided into two groups according to the presence of hypoenhancement on T2 images. Thirty-two patients showed an hypointense stria within the high signal intensity zone on T2-weighted images; all these patients showed midmural PMD on LGE. Among the remaining 76 patients, only 14 (18.4%) showed PMD in the subendocardial region. The angiographic outcome was worse in patients with hemorrhagic AMI, with a lower prevalence of TIMI 3 (65.6% vs. 96.1%, P = 0.017) and higher prevalence of myocardial blush grade 0 (84.4% vs. 13.2%, P < 0.001) post-PCI. Conclusions: T2-weighted CMR in reperfused AMI allows identification of hemorrhage, related to PMD areas on LGE images and to a worse reperfusion profile on angiography. These features open new avenues of investigation for prognostic assessment of reperfused AMI. (Echocardiography 2010;27:1120-1129)