1354800 - Myocardial Scarring by Magnetic Resonance Predicts Sudden Cardiac Death in Pediatric Patients with Hypertrophic Cardiomyopathy

There is early evidence late gadolinium enhancement, a cardiac magnetic resonance (CMR) imaging surrogate of myocardial scarring, may be associated with an increased sudden cardiac death (SCD) risk in children. However, the role of LGE in SCD risk stratification in childhood hypertrophic cardiomyopathy (HCM) is unknown, as previous risk scores did not include quantitative LGE as a risk variable.

Methods:

We retrospectively analyzed the CMR images and reviewed the outcomes in 700 pediatric HCM patients from 38 centers who had LGE imaging.

Results: Amongst 700 patients, 74% were male, with a mean age of 14.1+/- 4.8 years.  During a mean follow up of 2.8 +/- 2.9 years, 35 experienced an episode of SCD or equivalent (i.e. aborted cardiac arrest, sustained VT and/or appropriate AICD shock).  LGE was present in 33%, with a mean burden of 2.0 +/- 5.1% of LV myocardium.  In univariate analysis, presence of LGE was associated with an increased SCD risk (HR 3.8, p=0.0003).  Burden of LGE was also associated with an increased risk (HR 2.2 per 10% increase in LGE, p< 0.0001).  SCD risk was also associated with history of NSVT (HR 4.1, p=0.0009), and LV dysfunction (i.e. LVEF < 50%) (HR 2.8, p=0.009). LGE burden was independently associated with SCD risk and improved risk prediction when adjusted for AHA conventional risk factors (p=0.0007), ESC risk score (p< 0.0001), HCM Risk-Kids Score (p=0.0004), and the PRIMACY Score (p=0.0004).   Multivariable analysis resulted in a novel three-variable model consisting of 1) %LGE, 2) history of NSVT, and 3) LVEF (see table) that can be simply converted into an integer score to estimate 5-year sudden cardiac death risk, with a c-statistic of 0.77.

Conclusion:

Quantitative LGE is an independent risk factor for SCD in pediatric patients with HCM and provides incremental information to improve SCD risk stratification.  The proposed three-variable risk score with readily quantifiable metrics can be used to rapidly estimate individualized 5-year SCD risks for pediatric HCM patients.