Prognostic value of myocardial fibrosis on cardiac MRI in patients with ischemic cardiomyopathy, a systematic review

Background

The use of cardiac magnetic resonance imaging (c-MRI) in risk stratification for clinical outcomes of patients with ischemic cardiomyopathy (ICM) remains low.

Objectives

This systematic review investigated the prognostic value of myocardial fibrosis as assessed by late gadolinium enhancement (LGE) on c-MRI in patients with ICM for ventricular tachyarrhythmia, sudden cardiac death (SCD), or all-cause mortality.

Methods

We conducted a systematic review of the electronic databases Pubmed and Embase for relevant prospective English-language studies published between January 1990 and February 2019. All included articles were prospective studies that comprised of human participants greater than 18 years old with ischemic cardiomyopathy (ICM) and a primary or secondary prevention ICD, had a sample size >30 participants, had at least 6 months follow-up, and reported on ventricular tachyarrhythmia, SCD and all-cause mortality. A total of 90 articles related to ICM were identified and were subsequently screened independently by two authors. Pooled sensitivity and specificity of LGE were calculated using random-effects model.

Results

Eight studies with 1085 participants were included in the final analysis. The mean age of patients varied from 43–83 years, with most patients being men. The most common comorbidities reported included history of diabetes mellitus (22–62%), hyperlipidemia (40–86%), and hypertension (35–88%). The ejection fraction of each study was reported as mean or median, and varied from 22–35%. During a follow-up that ranged from 8.5 to 65 months, there were 110 ventricular arrhythmic events reported. The pooled sensitivity and specificity of LGE for ICD therapy delivered for ventricular arrhythmias were 0.79 (95% Cl: 0.66–0.87) and 0.28 (95% Cl: 0.14–0.46) respectively. For all-cause mortality, the pooled sensitivity and specificity of LGE were 0.76 (95% Cl: 0.40–0.93) and 0.41 (95% Cl: 0.14–0.75) respectively. While SCD was of significant interest to our review, only one of the studies reported on the association between LGE and SCD leading to the subsequent exclusion of SCD from the endpoint analysis.

Conclusion

LGE has high prognostic value in predicting adverse outcomes in patients with ICM and may provide helpful information for clinical decision-making related to SCD prevention. Our findings illustrate how LGE may improve current risk stratification, prognostication and selection of patients with ICM for ICD therapy.