Late Gadolinium Enhancement in Patients With Hypertrophic Cardiomyopathy and Preserved Systolic Function

BACKGROUND A high proportion of patients with hypertrophic cardiomyopathy (HCM) have evidence of late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR). OBJECTIVES This study sought to assess the incremental prognostic utility of LGE in patients with HCM. METHODS We studied 1,423 consecutive low-/intermediate-risk patients with HCM (age >= 18 years) with preserved left ventricular (LV) ejection fraction (mean age 66 +/- 14 years, 60% men) who underwent transthoracic echocardiography (TTE) (including dimensions and LV outflow tract gradients) and CMR (including LGE as a % of LV mass) at our center between January 2008 and December 2015. The primary composite endpoint was sudden cardiac death (SCD) and appropriate implantable cardioverter-defibrillator discharge. The percent 5-year SCD risk score was calculated. RESULTS The mean 5-year SCD risk score was 2.3 +/- 2.0. Mean maximal LV outflow tract gradient (TTE) was 70 +/- 55 mm Hg (median 74 mm Hg [interquartile range (IQR): 10 to 67 mm Hg]); indexed LV mass and LGE (both on CMR) were 91 +/- 10 g/m(2) and 8.4 +/- 12% (IQR: 0% to 19%); 50% had LGE on CMR. Of these, 458 were nonobstructive and 965 were obstructive (of which 686 were underwent myectomy). At 4.7 +/- 2.0 years of follow-up, 60 (4%) met the composite endpoint. On quadratic spline analysis, LGE >= 15% was associated with increased risk of composite events. In the obstructive subgroup, on competing risk regression analysis, >= 15% LGE (subhazard ratio: 3.04 [95% confidence interval: 1.48 to 6.10]) was associated with a higher rate and myectomy (subhazard ratio: 0.44 [95% confidence interval: 0.20 to 0.76]) was associated with a lower rate of composite endpoints (both p < 0.01). Similarly, sequential addition of LGE >= 15% and myectomy to % 5-year SCD risk score improved the log likelihood ratios from -227.85 to -219.14 (chisquare 17) and to -215.14 (chi-square 8; both p < 0.01). Association of % LGE with composite events was similar even in myectomy and nonobstructive subgroups. CONCLUSIONS In low-/intermediate-risk adult patients with HCM (obstructive, myectomy, and nonobstructive subgroups) with preserved systolic function, % LGE was significantly associated with a higher rate of composite endpoint, providing incremental prognostic utility. (C) 2018 by the American College of Cardiology Foundation.