Log in to MyACC
Hypertrophic Cardiomyopathy, Risk Stratification
Study Questions:
What is the incremental prognostic utility of late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) in patients with hypertrophic cardiomyopathy (HCM)?
Methods:
The investigators 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 a single 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. To assess for the association of various predictors with all-cause mortality and appropriate ICD discharge, multivariable Cox proportional hazards analysis was utilized.
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): 10-67 mm Hg]); indexed LV mass and LGE (both on CMR) were 91 ± 10 g/m2 and 8.4 ± 12% (IQR, 0-19%); 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, 1.48-6.10) was associated with a higher rate, and myectomy (subhazard ratio, 0.44; 95% confidence interval, 0.20-0.76) 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:
The authors concluded that 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.
Perspective:
This study reports that LGE (quantified as a % of LV mass) provided incremental prognostic utility over standard SCD risk stratification such as the European Society of Cardiology SCD risk score. In addition, % LGE also significantly reclassified risk of SCD and/or appropriate ICD discharge. It appears that in patients with HCM, SCD risk could be refined based on specific patient population characteristics, presence/absence of obstruction, and potential additional risk factors like LGE assessed by CMR. Additional prospective, multicenter studies are indicated to validate risk stratification algorithms for HCM that use LGE.
Keywords: Arrhythmias, Cardiac, Cardiomyopathy, Hypertrophic, Death, Sudden, Cardiac, Defibrillators, Implantable, Echocardiography, Gadolinium, Heart Failure, Magnetic Resonance Imaging, Risk Factors, Secondary Prevention, Stroke Volume
< Back to Listings
