Late gadolinium enhancement on cardiac MRI: A systematic review and meta-analysis of prognosis across cardiomyopathies.

Background: Late gadolinium enhancement (LGE) on cardiac MRI has been shown to predict adverse outcomes in a range of cardiac diseases. However, no study has systematically reviewed and analyzed the literature across all cardiac pathologies including rare diseases.

Methods: PubMed, EMBASE and Web of Science were searched for studies evaluating the relationship between LGE burden and cardiovascular outcomes. Outcomes included all-cause mortality, MACE, sudden cardiac death, sustained VT or VF, appropriate ICD shock, heart transplant, and heart failure hospitalization. Only studies reporting hazards ratios with LGE as a continuous variable were included.

Results: Of the initial 8928 studies, 95 studies (23,313 patients) were included across 19 clinical entities. The studies included ischemic cardiomyopathy (7182 patients, 33 studies), hypertrophic cardiomyopathy (5080 patients, 17 studies), non-ischemic cardiomyopathy not otherwise specified (2627 patients, 11 studies), and dilated cardiomyopathy (2345 patients, 14 studies). Among 42 studies that quantified LGE by percent myocardium, a 1 % increase in LGE burden was associated with life-threatening ventricular arrhythmias (LTVA) with a pooled hazard ratio of 1.04 (CI 1.02-1.05), and MACE with a pooled hazard ratio of 1.06 (CI 1.04-1.07). The risk of these events was similar across disease types, with minimal heterogeneity.

Conclusions: Despite mechanistic differences myocardial injury, LGE appears to have a fairly consistent, dose-dependent effect on risk of LTVA, MACE, and mortality. This data can be applied to derive a patient's absolute risk of LTVA, and therefore can be clinically useful in informing decisions on primary prevention ICD implantation irrespective of the disease etiology.