Cardiovascular magnetic resonance-derived intramyocardial hemorrhage after STEMI: Influence on long-term prognosis, adverse left ventricular remodeling and relationship with microvascular obstruction☆
Introduction
In ST-segment elevation myocardial infarction (STEMI) timely reperfusion is the primary therapeutic goal [1]. Nevertheless, despite re-established epicardial blood flow in the infarct related artery, microvascular perfusion might still be impaired, a phenomenon referred to as microvascular obstruction (MVO) [2]. Moreover reperfusion itself may cause additional myocardial damage termed reperfusion injury with intramyocardial hemorrhage (IMH) [3].
These phenomena can be readily assessed using cardiovascular magnetic resonance imaging (CMR) allowing for a state of the art assessment of the post-infarction patient [4], [5]. Using T2 weighted sequences, CMR allows for the appreciation of myocardial edema representing the area at risk in an acute STEMI [6]. Within these hyperdense areas of myocardial edema, hypodense cores can appear and are suspected to reflect IMH [7], [8].
Additionally, CMR allows for an exact delineation of infarct size in late gadolinium enhancement (LGE) sequences. Dark areas within the core of the infarct zone have been described as MVO resulting from impaired microvascular perfusion due to multifactorial causes including edema, microembolization and inflammatory response [9], [10].
MVO has been linked to adverse outcome and left ventricular (LV) remodeling [5], [11], [12]. Emerging data indicates that the presence of IMH also brings about a higher rate of cardiovascular events [13], nevertheless the existing prognostic data are scarce and it is unclear whether or not both phenomena represent different entities or are representations of the same pathology in different imaging sequences.
In the present study we aimed to assess [1] the long-term prognostic value of CMR-derived IMH in a large unselected population of STEMI patients, [2] the influence of IMH on LV remodeling at the 6th month, [3] to compare the additional value of T2 imaging beyond LGE imaging for these purposes and [4] to assess the relationship of IMH with MVO.
Section snippets
Study group
We prospectively included patients admitted to our institution with a first STEMI from November 2001 to December 2010. Patients who died or had a reinfarction or otherwise complicated clinical course or cardiac surgery as well as those who denied participation in the registry, were transferred to other hospitals after reperfusion or those who had contraindications to CMR were not included in the study. Patients underwent CMR at 1 week and, in order to evaluate LV remodeling, at 6 months after
Results
The clinical, angiographic and CMR characteristics of the study group are shown in Table 1. IMH was present in 102 patients (34%) and was associated with younger age (57 ± 12 years vs. 59 ± 12, p = .03), a higher heart rate on admission (84 ± 20 bpm vs. 79 ± 19, p = .04), diabetes (25% vs. 14%, p = .02) and a higher rate of Killip class > 1 (18% vs. 6%, p = .002). Patients with IMH more often had received rescue angioplasty (23% vs. 7%, p < .0001) and had a higher rate of anterior infarctions with involvement of
Discussion
The present study investigates the prognostic value of a comprehensive state-of-the-art CMR examination including T2 imaging-derived IMH in a large population of STEMI patients. It shows that the presence of IMH in the 1st week CMR scan after STEMI indicated a higher rate of MACE and was an independent predictor of MACE during follow up. Additionally, evidence of IMH on the 1st week CMR scan was also an independent prognosticator of adverse LV remodeling in terms of dLVESV at the 6th month.
We
Limitations
The present study has some limitations. CMR studies were evaluated by a single expert observer, despite the excellent intraobserver variability; this might limit the generalizability of our results.
Patients who died on admission or early after or who had a complicated clinical course due to prolonged cardiogenic shock were not included into our registry. Also, some patients were transferred to other hospitals after successful PCI and also could not be included. Finally, and a limitation of
Conclusions
The presence of IMH on a post-STEMI CMR scan is an independent prognosticator of adverse prognosis and LV remodeling during follow-up. Nevertheless, addition of T2 information did not improve the predictive capability for these purposes beyond established LGE-derived and cine CMR parameters due to a strong interrelation of IMH and MVO. Nevertheless, T2 imaging remains a unique technique for evaluating the presence of IMH and its pathophysiological and clinical repercussions which might
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2022, Clinical RadiologyCitation Excerpt :In another T1-and T2-mapping-based study conducted by Mordi et al. including 300 patients,18 it was found that T1-and T2-mapping were potentially significant for differentiating between athletes' hearts and patients with early dilated cardiomyopathy, and could be used whenever differentiation between these two phenotypes is inconclusive using standard imaging techniques. As reported previously, intramyocardial haemorrhage (IMH) often occurs after successful reperfusion in patients with AMI, and it is associated with more extensive myocardial necrosis.19,20 Reinstadler et al. demonstrated that T2-mapping might provide prognostic information for the incidence of MACEs.