Effect of microvascular obstruction and intramyocardial hemorrhage by CMR on LV remodeling and outcomes after myocardial infarction: a systematic review and meta-analysis

Abstract

The goal of this systematic analysis is to provide a comprehensive review of the current cardiac magnetic resonance data on microvascular obstruction (MVO) and intramyocardial hemorrhage (IMH). Data related to the association of MVO and IMH in patients with acute myocardial infarction (MI) with left ventricular (LV) function, volumes, adverse LV remodeling, and major adverse cardiac events (MACE) were critically analyzed. MVO is associated with a lower ejection fraction, increased ventricular volumes and infarct size, and a greater risk of MACE. Late MVO is shown to be a stronger prognostic marker for MACE and cardiac death, recurrent MI, congestive heart failure/heart failure hospitalization, and follow-up LV end-systolic volumes than early MVO. IMH is associated with LV remodeling and MACE on pooled analysis, but because of limited data and heterogeneity in study methodology, the effects of IMH on remodeling require further investigation.

Keywords: cardiac magnetic resonance; ejection fraction; intramyocardial hemorrhage; left ventricular remodeling; microvascular obstruction.

Copyright © 2014. Published by Elsevier Inc.

Figures

FIGURE 1. Cardiac Magnetic Resonance (CMR) Images From a 46-Year-Old Man With Diabetes and Chest Pain

(A) First-pass perfusion (FPP) image shows a region of hypoperfusion in the anteroseptum (early microvascular obstruction [EMVO]). (B) Phase-sensitive inversion recovery (PSIR) sequence reveals presence of myocardial infarction (MI) with large area of late microvascular obstruction (LMVO). These findings were consistent with an acute MI in a diagonal branch that was originally missed on (C) cardiac catheterization (arrow shows proximal diagonal branch obstruction).

FIGURE 2. Example Images From a Study of Reperfused Acute MI in a Porcine Model

The images from the first animal (top) show (A) decreased perfusion in the mid-anteroseptal wall on FPP imaging, (B) an area of intramyocardial hemorrhage on T2* mapping, and (C) a corresponding hypointense area on phase-sensitive late gadolinium enhancement imaging, consistent with microvascular obstruction (MVO) with IMH. Images from the second animal (bottom) (D) demonstrate an area of reduced perfusion on FPP imaging, (E) T2* maps do not demonstrate any IMH, and (F) late gadolinium enhancement images demonstrate the absence of MVO or IMH.

FIGURE 3. Transmural Anteroseptal and Lateral Hemorrhagic MI in a Patient Who Died of Cardiogenic Shock After Acute MI and Who Had Undergone Coronary Recanalization

Gross anatomic image obtained at the time of autopsy (A), histology image after staining with Heidenhain trichrome stain (B), and ex vivo T2 CMR image from the short-axis slice (C) show the changes. Adapted with permission from Basso et al. (43).

FIGURE 4. Images From a Mongrel Dog in Which MI Was Experimentally Induced

CMR was performed day 3 after reperfusion in which T2*-weighted gradient echo imaging was performed. Ex vivo, thioflavin S imaging, and triphenyl tetrazolium chloride staining were performed to assess for MVO, hemorrhage, and myocardial necrosis. Adapted with permission from Kumar et al. (45). CMR = cardiac magnetic resonance; LGE = late gadolinium enhancement; TTC = triphenyl tetrazolium chloride.

FIGURE 5. QUORUM Diagram Showing Details of the PubMed Search Conducted Through January 2014 on 3 Topics

1) MVO and left ventricular (LV) remodeling; 2) MVO and major adverse cardiac events (MACE); and 3) IMH and LV remodeling. IMH = intramyocardial hemorrhage; IS = infarct size; LGE = late gadolinium enhancement; LV = left ventricular; LVEDD = left ventricular end-diastolic diameter; LVEF = left ventricular ejection fraction; LVESD = left ventricular end-systolic diameter; MACE = major adverse cardiac events; MVO = microvascular obstruction.

FIGURE 6. Pooled Odds Ratios for the Association of EMVO and Adverse Cardiac Outcomes

(A) MACE, (B) cardiac death, (C) recurrent MI, and (D) congestive heart failure (CHF) or CHF-related hospitalizations. CI = confidence interval; MVO = microvascular obstruction.

FIGURE 7. Pooled Odds Ratios for the Association of LMVO and Adverse Cardiac Outcomes

(A) MACE, (B) cardiac death, (C) recurrent MI, and (D) CHF or CHF-related hospitalizations. Abbreviations as in Figure 6.