Abstract 16793: The Impact of Late Gadolinium Enhancement on Sudden Death Risk Stratification in Older Patients With Hypertrophic Cardiomyopathy

Abstract

Background: Extensive late gadolinium enhancement (LGE) is now recognized as a risk factor for sudden cardiac death (SCD) in patients with hypertrophic cardiomyopathy (HCM). However, risk for SCD is very low in older (≥60 years) HCM patients, and therefore utility of assessing LGE for risk stratification in this subgroup of patients is uncertain. Objectives: We assessed the relationship between LGE and SCD in older HCM patients and compared this risk to younger patients. Methods: A total of 1735 HCM patients undergoing cardiovascular magnetic resonance (CMR) for initial evaluation from 4 medical centers were followed up for a median of 3.7 years. LGE was semiautomatically quantified by manually adjusting a grayscale threshold. Results: We identified 638 HCM patients ≥60 years of age (up to 90 years), with LGE present in 337 patients (53%), including 28 patients (4%) with extensive LGE occupying ≥15% of left ventricular mass. Neither the presence nor extent of LGE was associated with increased risk for SCD events (HR ad , 1.13; 95%CI, 0.20-6.44, p=0.89 and HR ad per 10% increase, 1.49; 95%CI, 0.46-3.28, p=0.38, respectively), even after adjustment for other relevant disease variables. The risk for SCD at five years was 4% in older HCM patients with extensive LGE ≥15%, and not different compared to older patients with less LGE (1.0%, p=0.25). The performance of the AHA/ACC SCD risk model was not enhanced in older HCM patients by the addition of LGE (continuous net reclassification index, 0.25; 95%CI, -0.35-0.85, p=0.42). In contrast, the extent of LGE was associated with increased SCD risk in patients <60 years, with extensive LGE associated with a 3-fold greater risk. Conclusions: The extent of LGE was not associated with increased SCD risk in HCM patients ≥60 years, even in the presence of other risk markers. These data suggest a limited role for CMR with LGE in older HCM patients to inform SCD risk stratification.