Direct oral anticoagulants versus warfarin for atrial fibrillation in patients with transthyretin cardiac amyloidosis: a retrospective cohort analysis

Patients with transthyretin cardiac amyloidosis (ATTR-CA) and atrial fibrillation (AF) have increased risk for left atrial thrombi, necessitating anticoagulation therapy if bleeding risk is not prohibitive. Limited data is available comparing the use of direct oral anticoagulants (DOACs) to warfarin in this population.

To evaluate and compare clinical efficacy and safety outcomes of DOACs versus warfarin in patients with ATTR-CA and AF.

We conducted a retrospective cohort study using the TriNetX Network, which includes data from over 140 million patients, between 2014 and 2022. Adults (aged ≥18 years) with ATTR-CA and AF were identified. These patients were further categorized into two groups: one cohort which utilized DOACs for oral anticoagulation and the other cohort on warfarin. 1:1 propensity score matching (PSM) was utilized to balance baseline characteristics between the two cohorts. The primary outcome was rate of stroke, with secondary outcomes including all-cause death, all-cause hospitalizations, and acute heart failure exacerbations. Safety outcomes included intracranial hemorrhage, gastrointestinal hemorrhage, and hematuria. Adjusted odds ratios (aORs) with 95% confidence intervals (CIs) were calculated.

Among 8,214 adults with ATTR-CA and AF, 5,774 patients were on a DOAC while 2,440 patients were on warfarin. After PSM, 2,425 patients were included in each group. The use of DOACs for AF in patients with ATTR-CA was associated with a significantly lower risk of ischemic stroke compared to warfarin (5.7% versus 7.3%, aOR 0.771 [95% CI, 0.612-0.971]) by the end of the one year follow up. There were no differences in all-cause mortality (19.8% versus 21%, aOR 0.927 [95% CI, 0.806-1.066]), all-cause hospitalizations (19.2% versus 21.6%, aOR 0.863 [95% CI, 0.624-1.195]) or heart failure exacerbations (43.6% versus 46%, aOR 0.906 [95% CI, 0.809-1.015]). Safety outcomes favored DOACs over warfarin, with a lower risk of intracranial hemorrhage (4.5% versus 7.8%, aOR 0.565 [95% CI, 0.444-0.720]), and comparable rates of GI hemorrhage and hematuria.

DOACs may be safely used in ATTR-CA patients with AF, offering a lower risk of stroke compared to warfarin and a more favorable safety profile. These findings emphasize the potential advantages of DOACs in this population and underline the need for prospective studies to validate these results.