Abstract 4145698: Temporal Trends in Survival and Hospitalizations in Transthyretin Cardiac Amyloidosis with and without LV Systolic Dysfunction

Background: The impact of left ventricular systolic dysfunction on survival and hospitalizations in patients with transthyretin cardiomyopathy (ATTR-CM) remains underexplored. Methods: Patients with confirmed ATTR-CM were categorized into HFrEF (LVEF < 50%) and HFpEF (LVEF ≥ 50%) groups. Regression models identified predictors of reduced ejection fraction. Kaplan-Meier survival analysis, multivariable Cox proportional hazards models, and time-varying Cox models were used to assess survival and heart failure (HF) hospitalization rates. Results: 132 patients with ATTR-CM were enrolled between 2015 and 2020 and followed for 4 years. Of these, 57 (43%) had HFrEF and 47% were on Tafamidis. Logistic regression showed no association between clinical characteristics and HFrEF status. Kaplan-Meier analysis showed no significant difference in HF hospitalization rates between HFrEF and HFpEF patients (58% vs 44%, respectively, p=0.110). When examining mortality, unadjusted Kaplan-Meier analysis showed a trend towards higher mortality in HFrEF patients compared to HFpEF patients. (p=0.066). Multivariable Cox analysis revealed that, after controlling for Tafamidis use (39% and 52% in HFrEF and HFpEF, respectively), HFrEF was associated with a higher risk of mortality compared to HFpEF (HR 1.99 [1.056–3.746], p=0.017). Additionally, time-varying Cox modeling indicated that HFrEF significantly predicted early mortality (p<0.0001), with the impact of HFrEF on mortality diminishing over time due to a significant interaction term between HFrEF and time (p<0.0001). Conclusion: In ATTR-CM patients, the risk of mortality of HFrEF patients compared to HFpEF patients is higher initially and equalizes with time, with no difference in HF hospitalization. The mechanism underlying this intriguing trend needs further study.