1357730 - Role of Cardiac MRI in prognostication of hypertrophic cardiomyopathy in a large single center south Asian cohort

Hypertrophic cardiomyopathy (HCM) is a common inherited cardiac disorder and is known to cause sudden cardiac death (SCD). Cardiac MR (CMR) has shown promising results in risk stratifying patients in predicting major adverse cardiac events (MACE). These studies are primarily focused on Caucasian patients and no long-term data is available in South Asian patients. This study looks at the role of CMR derived parameters in risk stratification of South Asian patients with HCM.

Methods:

Prospective cross-sectional study of all HCM patients who underwent CMR examination in a large tertiary care cardiac center in India, between Jan 2016 and Dec 2021. Patients were invited to participate in a telephonic interview and detailed history relating to patient symptomatology and MACE (history of syncope, cardiac demise, shock delivery of defibrillator and/or hospitalisation due to cardiac cause) were recorded. Multiple CMR parameters were analysed for risk stratification including: maximum left ventricular (LV) wall thickness, type of HCM, LV outflow tract obstruction (LVOTO), LV cavity obstruction, late Gadalonium enhancement (LGE), fibrotic burden, myocardial native T1 value, LV ejection fraction (LVEF), right ventricular (RV) involvement and co-existing infarction.

Results:

Amongst 887 qualified patients, 418 (47%) participated in the study. The mean follow-up period was 2.4 years (range of 6 to 60 months). The mean age of the patients was 42.7 years (range 18-79 years) and majority were men (81%). MACE was recorded in 74 patients (17.7%), and a statistically significant association (P< 0.05) was observed with LVEF (p:0.003), fibrotic burden (p:0.017) and raised native T1 (p:0.03).

Myocardial fibrosis and systolic basal cavity obliteration were specific ( >70%) and LV wall thickness ( >21 mm) and native T1 ( >1312 ms) were highly sensitive ( >70%) in prediction of MACE. Patients with a fibrotic burden of more than 9% were twice likely to have a MACE than others.

Conclusion:

CMR is a powerful non-invasive tool in risk stratification of HCM patients. CMR predictors of MACE are different between Caucasians and South Asian patients. LVEF, fibrotic burden and raised native T1 were significant predictors of MACE in Sought Asian population. Contrary to other published studies, LV wall thickness of >30 mm and LVOTO were not a predictor of MACE in our population. Fibrotic burden of 9% is a predictor of MACE compared to published literature of 15%. Myocardial morphology and expression of HCM is likely different in South Asian patients. Therefore, different risk predictors and management strategies may have to be employed in management of South Asian patients with HCM.