Causes of Cardiovascular Hospitalization and Death in Patients With Transthyretin Amyloid Cardiomyopathy (from the Tafamidis in Transthyretin Cardiomyopathy Clinical Trial [ATTR-ACT])

In the Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT), tafamidis significantly reduced mortality and cardiovascular (CV)-related hospitalizations compared with placebo in patients with transthyretin amyloid cardiomyopathy (ATTR-CM). This analysis aimed to assess the causes of CV-related death and hospitalization in ATTR-ACT to provide further insight into the progression of ATTR-CM and efficacy of tafamidis. ATTR-ACT was an international, double-blind, placebo-controlled, and randomized study. Patients with hereditary or wild-type ATTR-CM were randomized to tafamidis (n = 264) or placebo (n = 177) for 30 months. The independent Endpoint Adjudication Committee determined whether certain investigator-reported events met the definition of disease-related efficacy endpoints using predefined criteria. Cause-specific reasons for CV-related deaths (heart failure [HF], arrhythmia, myocardial infarction, sudden death, stroke, and other CV causes) and hospitalizations (HF, arrhythmia, myocardial infarction, transient ischemic attack/stroke, and other CV causes) were assessed. Total CV-related deaths was 53 (20.1%) with tafamidis and 50 (28.2%) with placebo, with HF (15.5% tafamidis, 22.6% placebo), followed by sudden death (2.7% tafamidis, 5.1% placebo), the most common causes. The number of patients with a CV-related hospitalization was 138 (52.3%) with tafamidis and 107 (60.5%) with placebo; with HF the most common cause (43.2% tafamidis, 50.3% placebo). All predefined causes of CV-related death or hospitalization were less frequent with tafamidis than placebo. In conclusion, these data provide further insight into CV disease progression in patients with ATTR-CM, with HF the most common adjudicated cause of CV-related hospitalization or death in ATTR-ACT. Clinical trial registration ClinicalTrials.gov: NCT01994889.