Abstract 17374: Prognostic Utility of Intermediate-Signal-Intensity Late Gadolinium Enhancement in Patients with Hypertrophic Cardiomyopathy
Background: Intermediate signal-intensity (SI) late gadolinium enhancement (LGE) has been shown to predict ambulatory ventricular tachyarrhythmias in patients with hypertrophic cardiomyopathy (HCM). However, its prognostic utility in predicting sudden death and heart failure is unknown.
Methods: Cine and contrast-enhanced CMR were performed on 1293 HCM patients (46±17 years; 63% males).
Areas of LGE in the left ventricle (LV) were quantified by using grayscale threshold SI intensity cutoff values for intermediate-SI (≥4 and <6 SD above mean SI of normal myocardium), high-SI (≥6 SD above normal), a combination of high and intermediate-SI (≥4sd above normal), and by visual quantification. Mean follow-up was 3.4±1.7 years.
Results: LGE was identified in 545 (42%) patients. Intermediate-SI LGE occupied 4.8±4.2% LV mass, high-SI LGE 6.6 ± 9.3 %, the combination of high and intermediate LGE 11±12% and visually-quantified LGE 9.2±10.3%. Sudden cardiac death (SCD) occurred in 37 (2.9%), and heart failure-related events occurred in 156(12%). Multivariable Cox analysis showed intermediate-SI LGE, high-SI LGE, the combination of intermediate and high-SI LGE, and visually-quantified LGE were all strong independent predictors of SCD (p<0.05) and heart failure events (p<0.01). However, receiver operating characteristic analysis showed no significant difference in the discriminating ability between the different LGE thresholds for predicting SCD risk (C-indexintermediate-SI LGE 0.655, C-indexhigh-SI LGE 0.679, C-indexcombination 0.664, C-indexvisual-LGE 0.665; p>0.05 between thresholds) or in predicting heart failure risk (C-indexintermediate-SI LGE 0.815, C-indexhigh-SI LGE 0.802, C-indexcombination 0.800, C-indexvisual-LGE 0.802; p>0.05 between thresholds).
Conclusion: Despite its previous association with ambulatory ventricular tachyarrhythmias, intermediate signal-intensity LGE did not appear to be a superior predictor for identifying HCM patients at high risk for sudden death and heart failure compared to high signal-intensity LGE or visually-quantified LGE. Therefore, for the purposes of sudden death and heart failure risk stratification, visual assessment of LGE should be considered for LGE quantification in HCM.
- © 2012 by American Heart Association, Inc.