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 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 (chi-square 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.