Has late gadolinium enhancement an incremental value for management of patients with hypertrophic cardiomyopathy?

Abstract

Purpose: Some authors suggest the presence of fibrosis, identified with Late Gadolinium Enhancement (LGE) in Cardiac Magnetic Resonance (CMR), can be related to the subject arrhythmogenic risk in patients (P) with Hypertrophic Cardiomyopathy (HCM). We aim to examine the association between clinical-morphological variables, risk factors for sudden cardiac death and LGE findings in a population with HCM. Methods: From a population of 74 HCM P, we studied 55 P (51% male; age 63±18 years) who performed CMR. They were divided in 2 groups: LGE+ (with LGE; n=25; 45.5%) and LGE- (without LGE; n=30; 54.5%). Follow-Up (FU) regarding ventricular arrhythmias and Mortality (M) was done. Results: HCM diagnosis was done at a younger age (53±17 vs 61±17; p=0.051) in LGE+. No differences were found regarding gender, cardiovascular risk factors, previous syncope, NYHA class, ambulatory medication, identification of HCM mutation, electrocardiographic criteria for left ventricular hypertrophy or atrial fibrillation. LGE+ more often had family history of sudden death (32% vs 3.4%; p=0.008) and known coronary artery disease (12.0% vs 0%; p=0.088). They also presented a trend towards higher NTproBNP values (5151±7882 vs 1489±2422, p=0.089). Blood pressure response during exercise test was similar. Regarding echocardiogram LGE+ had higher interventricular septum (IVS) thickness (18.8±5.1 vs 15.9±3.09; p=0.017) and left atrium (LA) volume (102.1±33.7 vs 85.4±32.9, p=0.078); more often presented a restrictive pattern of diastolic dysfunction (8.7% vs 4.2%; p=0.021) with a higher E/E' relation (16.5±7.6 vs 12.0±5.9; p=0.022); and left ventricular systolic impairment (24.0% vs 3.3%; p=0.039). No differences were found concerning HCM phenotype, presence of obstruction or mitral regurgitation severity. CMR reinforced the association between LGE+ and previously echocardiographic findings: higher LA volume (32.88±3.6 vs 29.3±5.2; p=0.034); IVS thickness (21.3±4.1 vs 17.9±2.8; p=0.001) and left ventricle ejection fraction (64.1±8.9 vs 68.0±8.6; p=0.064). LGE+ more often had an implantable cardioverter defibrillator (ICD) (36.0% vs 6.7%, p=0.006). At FU (32.0±74.4 months), no differences were found regarding the frequency of ventricular arrhythmias, appropriated ICD therapies or mortality. Conclusions: In this population the presence of LGE emerges as a risk marker, associated with the classical predictors of sudden cardiac death in HCM patients. However its independent association to clinical events requires the study of larger populations, so it can be interpreted as having an incremental value for risk stratification of these P.