Microvascular Obstruction Remains a Portent of Adverse Remodeling in Optimally-Treated Patients with Left Ventricular Systolic Dysfunction After Acute Myocardial Infarction

OBJECTIVES: Microvascular obstruction (MO) is associated with large acute myocardial infarction (AMI) and lower left ventricular (LV) ejection fraction, and predicts greater remodeling, but whether this effect is abolished by contemporary anti-remodeling therapies is subject to debate. We examined the influence of several infarct characteristics, including MO, on LV remodeling in an optimally-treated post-AMI cohort, using contrast-enhanced cardiac magnetic resonance (ceCMR).

METHODS: 100 patients (mean age 58.9±12 years, 77% male) underwent ceCMR at baseline (~4 days), 12 and 24 weeks. The effects on LV remodeling (i.e. change in LV end-systolic volume index [LVESVi]) of infarct site, transmurality, endocardial extent, and the presence of early and late MO were analyzed.

RESULTS: Mean baseline infarct volume index decreased from 34.0 (21.2) mL/m2 to 20.9 (12.9) mL/m2 at 24 weeks (p<0.001). Infarct site had no influence on remodeling, but greater baseline infarct transmurality (r=0.47, p<0.001) and endocardial extent (r=0.26, p<0.01) were associated with higher LVESVi. Early MO was seen in 69 (69%) of patients and persisted, as late MO, in 56 (56%). Patients with late MO underwent significantly greater remodeling than those without MO (LVESVi +4.1 [13.4] vs. -7.0 [12.7] mL/m2 respectively, p=0.001); those with early MO only displayed an intermediate LVESVi (-4.9 [13.0] mL/m2). Importantly, late MO was seen frequently despite optimal coronary blood flow having been restored at angiography.

CONCLUSIONS: Late MO on pre-discharge ceCMR remains an ominous predictor of adverse LV remodeling despite powerful anti-remodeling therapy, and may be useful in the risk-stratification of survivors of AMI. Haason Reddick Authentic Jersey

PMID: 20348438

Posted in Magnetic Resonance Imaging and tagged , , , , , , .

One Comment

  1. One important comment by the authors is that “the presence or absence of late MO divided patients into two distinct groups: those with late MO adverse remodeled while those without late MO reverse remodeled despite a high revascularization rate and very high prescription of evidence-based anti-remodeling medications across the cohort.”

    Another interesting finding highlighted by the authors is that “We found that MO was associated with significantly less remodeling in eplerenone- than in placebo-treated patients. This is of considerable interest, as the role of aldosterone antagonists on top of ACE inhibitors/ARBs and beta blockers in post-MI remodeling is still controversial. Our novel results support an anti- remodeling role for eplerenone in those at greatest risk of remodeling, i.e. those with MO.”

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