Prognostic Role of the Progression of Late Gadolinium Enhancement in Hypertrophic Cardiomyopathy

In hypertrophic cardiomyopathy (HCM), Late Gadolinium Enhancement (LGE) extent ≥15% of left ventricular (LV) mass is considered a prognostic risk factor. LGE extent increases over time and the clinical role of the progression of LGE over time (LGE-rate) was not prospectively evaluated. We sought to evaluate the prognostic role of LGE-rate in HCM. We enrolled 105 patients with HCM who underwent cardiac-MR at baseline (CMR-I) and after ≥2 years of follow-up (CMR-II). LGE-rate was defined as the ratio between the increase of LGE extent (g) and the time interval (months) between examinations. A combined endpoint of sudden cardiac death, resuscitated cardiac arrest, appropriate ICD intervention and sustained VT was used (hard events). The percentage of patients with LGE extent ≥15% increased from 9% to 20% from CMR-I to CMR-II (p=0.03). During a median follow-up of 52 months, 25 hard events were recorded. The presence of LGE≥15% at CMR-II allowed a significant reclassification of the risk of patients than at LGE≥15% at CMR-I (NRI 0.21, p=0.046). At MaxStat analysis the optimal prognostic cut-point for LGE-rate was >0.07 g/months. At Kaplan-Meier curve patients with LGE-rate>0.07 had worse prognosis than those without (p<0.0001). LGE-rate>0.07 allowed a significant reclassification of the risk compared to LGE≥15% at CMR-I and at CMR-II (NRI 0.49, p=0.003). In multivariable models, LGE-rate>0.07 was the best independent predictor of hard events. In conclusion, CMR should be repeated after 2 years to reclassify the risk sudden death of those patients. High LGE-rate may be considered a novel prognostic factor in HCM.