LGE-CMR may help guide ICD decisions

Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) imaging offers a powerful tool for risk stratifying patients with non-ischemic cardiomyopathy, a meta-analysis published online Dec. 20 in Circulation Cardiovascular Imaging determined. LGE-CMR may provide additional information for selecting patients in need of implantable cardioverter-defibrillators (ICDs).

Researchers have published numerous small, single-center studies that evaluated the prognostic value of LGE-CMR in patients with non-ischemic cardiomyopathy. Sujith Kuruvilla, MD, of the University of Virginia Health System in Charlottesville, and colleagues performed a meta-analysis in an effort to overcome some of the limitations of such small studies.

Using Cochrane CENTRAL, EMBASE and PubMed, they identified nine studies published in peer-reviewed journals that reported prognostic results for LGE-CMR in patients with non-ischemic cardiomyopathy. Their primary endpoints were all-cause mortality, heart failure hospitalization and a composite of sudden cardiac death (SCD) and aborted SCD. Outcomes were reported as an estimation of pooled odds ratios (ORs) and annualized event rates.   

The nine studies had a mean follow-up of 30 months, included a total of 1,488 patients and provided data on at least one of the outcomes of interest. Patients had a mean left ventricular ejection fraction (LVEF) of 37 percent on CMR and LGE was present in 38 percent.

Patients with LGE had higher overall mortality (OR 3.27), heart failure hospitalization (OR 2.91) and the SCD composite (OR 5.32) than patients without LGE. Annualized event rates for those with and without LGE for the three endpoints were 4.7 percent vs. 1.7 percent, 5.03 percent vs. 1.8 percent and 6 percent vs. 1.2 percent, respectively.

“This meta-analysis is the first large-scale analysis to support the role of LGE-CMR in identifying NICM [non-ischemic cardiomyopathy] patients at risk for SCD, HFH [heart failure hospitalization] and overall mortality, and it strengthens the conclusions of earlier studies concerning the role of LGE in a larger NICM patient population across multiple studies,” they wrote. 

Guidelines recommend ICD therapy for patients with LVEF of less than 35 percent to prevent SCD. Kuruvilla and colleagues proposed that, in addition to LVEF, cardiologists could use LGE-CMR to determine who might benefit from placement of ICDs, cardiac resynchronization therapy and other devices. They argued its use might reduce the number of patients exposed to potential complications from implantation and their costs.

They added that the meta-analysis relied on observational studies, used differing inclusion criteria and the pooled estimates did not adjust for potential confounders.