Abstract 4142952: Feature Tracking Global Longitudinal Strain in Long-term Risk Stratification of Hypertrophic Cardiomyopathy without Septal Reduction Therapy

Background: The significance of left ventricular global longitudinal strain (LV-GLS) for risk stratification of sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM) without septal reduction therapy remains to be investigated. Aims: To evaluate the prognostic utility of LV-GLS in a long-term follow-up HCM cohort without septal reduction therapy. Methods: We retrospectively enrolled 871 consecutive patients with HCM (mean age 49±13 years, 71% men) who underwent cardiac MRI in our center between January 2010 and December 2013. All study participants never received alcohol septal ablation or surgical myectomy during follow-up. LV-GLS were derived from cine cardiac MRI by using feature tracking method. The primary endpoint was SCD or SCD-equivalent events. The association between LV-GLS and SCD-related endpoints was evaluated by using time-dependent receiver operating characteristic (ROC) analysis, Kaplan-Meier analysis, and multivariable competing risk regression analysis. Results: During median follow-up of 8.8 years, SCD-related endpoint occurred in 45 HCM patients (5.2%). Patients suffering from SCD had higher European Society of Cardiology (ESC) Risk-SCD score (2.2 ± 0.6 vs. 2.6 ± 0.6, P < .001) and absolute LV-GLS (11.4 ± 3.7% vs. 9.3 ± 3.4%, P < .001). According to time-dependent analysis, 9% is an optimal cut-off value for absolute LV-GLS in predicting the primary outcome after a 10-year follow-up. On competing risk regression analysis, absolute LV-GLS ≤ 9% was associated with a higher rate of primary endpoints (subhazard ratio: 2.66 [95% confidence interval: 1.96 to 3.36]) after adjustment for known risk factors. Finally, LV-GLS provided incremental prognostic value over 2020 American College of Cardiology (ACC)/American Heart Association (AHA) risk model (log-likelihood ratios, -262.2 vs -266.2; P = .003) and 2022 ESC risk model (log-likelihood ratios, -268.4 vs -264.9; P = .009), respectively. In the subgroup with Class 3 of recommendation for implantable cardioverter defibrillator, patients with absolute LV-GLS ≤ 9% showed significantly worse prognosis than those with absolute LV-GLS > 9% (p = .002 and .004 for 2020 AHA guideline and 2022 ESC guideline, respectively). Conclusion: Feature tracking LV-GLS derived by cardiac MRI may enable further risk stratification for the subgroup of HCM patients who never accept septal reduction therapy in their lifetime, especially for those recognized as low-risk for SCD based on current guidelines.