Refining risk stratification in hypertrophic cardiomyopathy: the role of late gadolinium enhancement and syncope in predicting adverse outcomes

Abstract Background The presence of late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (MRI) is recognized as a significant marker of myocardial fibrosis and a predictor of adverse outcomes in hypertrophic cardiomyopathy (HCM). Nevertheless, the specific quantity of LGE that correlates with poor outcomes is still under debate. Therefore, this study sought to assess the combined impact of LGE presence and a history of syncopal events and its association with clinical prognosis. Methods Between May 2018 and June 2023, a total of 230 HCM patients was prospectively enrolled at our Medical University, a tertiary referral center. The primary endpoint was a composite of new-onset ventricular tachycardia (VT), appropriate ICD therapy, and all-cause mortality. Results Median age of enrolled patients was 56 (IQR 44-64) years and 40% (n=94) were female. Median interventricular septal thickness (IVS) was 21 (IQR 18–25) mm and 43 % (n=84) had significant left ventricular outflow tract obstruction (LVOTO). Over a median follow-up of 3.2 years, 30 patients (13%) met the composite endpoint. These patients had a significantly higher LGE quantity compared to the non-event group (1.1 % vs. % 9.0, P=0.012). An LGE threshold of 5.2% was identified as an optimal predictor of the composite endpoint, with an area under the curve of 0.72, which increased to 0.77 when including at least one syncopal event in medical history. LGE > 5.2% and/or syncope were independently associated with adverse outcomes after multivariable adjustment (Adj HR 7.26 [95%CI 2.54-20.72]). Furthermore, NTproBNP and hsTnT were associated with the presence of LGE or syncope (OR for a 1-unit increase in standardized log-transformed biomarker NTproBNP 3.35 [95%CI 1.42-10.85]; hsTnT 3.48 [95%CI 1.48-10.24], respectively). Interestingly, typically used variables for risk stratification, such as age, IVS or LVOT were not significantly associated with these cardiac biomarkers. Conclusion An extent of LGE > 5.2% and the history of at least one syncope are associated with unfavorable clinical outcomes in HCM patients. These findings call for detailed MRI appraisal and suggest adopting a holistic approach to accurately identify high-risk patients.