Prognostic stratification of end stage hypertrophic cardiomyopathy using cardiac magnetic resonance based late gadolinium enhancement granularity

Abstract Introduction End-stage hypertrophic cardiomyopathy (HCM) is a distinct and advanced form of the disease, defined by a left ventricular ejection fraction (LVEF) 50% and associated with a markedly poor prognosis. Cardiovascular magnetic resonance (CMR) has become a key imaging tool, particularly for assessing myocardial fibrosis through late gadolinium enhancement (LGE), a known prognostic marker in earlier stages of HCM. However, evidence on the prognostic relevance of LGE presence and distribution in end-stage HCM remains limited. Purpose To evaluate the prognostic value of the "LGE granularity" concept including its extent and location in end-stage HCM with LVEF50%. Methods All patients referred for CMR assessment of HCM at three French tertiary centers between 2008 and 2024 were retrospectively screened and all patients with HCM confirmed and a LVEF value 50% were included. The concept of "LGE granularity" was defined as a model combining LGE extent (3 segments) and location (septal). The primary endpoint was all-cause mortality, obtained from the French National Death Registry. Univariable and multivariable Cox proportional hazards models were used to assess the prognostic value of LGE features. Results Among 2,875 patients with HCM, 691 (53±7 years, 54% male) had a LVEF50% and were included in the study. After a median follow-up of 8.5 years (IQR 5.9–11.0), 226 patients died (32%). Using CMR, the presence of LGE was detected in 259 patients (37%) and, was strongly associated with mortality ((HR 3.37, 95% CI 2.57–4.42, p0.001, Figure 1), even after adjustment for known prognostic factors, including LVEF (HR 1.47, 95% CI 1.01–2.04, p=0.047). Different component of the LGE granularity model were independently associated with mortality after adjustment: LGE extent (HR 1.70, 95% CI 1.11–2.61, p0.001) and septal location (HR 1.77, 95% CI 1.13–2.78, p0.001) (Figure 2a and b). Conclusion In a large HCM cohort of end-stage HCM, LGE emerged as a strong and independent predictor of all-cause mortality. Moreover, among LGE-positive patients, the individual components of the "LGE granularity" concept were associated with adverse prognosis.