Better Outcomes After Initiation of Disease-Modifying Therapy in Patients with Transthyretin Cardiac Amyloidosis

Background: Advances in diagnostic criteria for transthyretin cardiac amyloidosis (ATTR-CM) and expanded insurance coverage for bone scintigraphy have facilitated earlier detection of ATTR-CM. However, whether these changes have translated into improved clinical outcomes among patients receiving disease-modifying therapy remains uncertain, especially in non-high-volume centers. Methods: Consecutive patients with ATTR-CM who started disease-modifying therapy at our institute between May 2019 and March 2025 were retrospectively analyzed. Baseline characteristics and clinical outcomes were compared between the early period (2019-2021) and the late period (2021-2025). Results: A total of 31 patients (median age 77 years, 77% male) were included. Duration of heart failure was significantly shorter and the dose of loop diuretics at baseline was significantly lower in the late period (p < 0.05 for both). The prevalence of National Amyloid Center (NAC) stage I at baseline tended to be higher in the late period (75.0% versus 53.5%, p = 0.273). The cumulative incidence of worsening heart failure hospitalization and all-cause death was significantly lower in the late period (6.3% versus 44.2%, p = 0.024) during a median follow-up of 5 years. NAC stage I at baseline was independently associated with the lower primary outcome with an adjusted hazard ratio of 0.10 (95% confidence interval 0.01-0.90, p = 0.040). Conclusions: Patients with ATTR-CM in the late group experienced more favorable clinical outcomes after disease-modifying therapy, probably due to earlier diagnosis and therapeutic intervention, although further studies are warranted to verify the hypothesis.