Acute ischemic stroke or TIA despite DOAC treatment: the contribution of DOAC plasma levels to understand pathophysiological mechanisms.

ABSTRACT:

Background

Ischemic stroke or transient ischemic attack (TIA) occurs in 1.4% of patients with atrial fibrillation (AF) per year despite treatment with direct oral anticoagulants (DOACs). This group of patients is poorly studied, and possible causes for this are not fully understood.

Objectives

The aim of the study was to analyze DOAC plasma levels in patients who had ischemic stroke or TIA despite treatment with DOAC.

Design

Monocentric retrospective study.

Methods

We selected consecutive DOAC-treated patients with acute ischemic stroke or TIA, admitted during a 2-year period, with measurement of DOAC levels ⩽24 h after hospital admission. Patients with and without low DOAC levels (<50 ng/mL) were compared.

Results

We included 163 patients with median age of 80 years, 46.6% of female sex. AF was the most frequent indication for DOAC (83.4%). Low DOAC levels were found in 42.3% of patients. Patients with low DOAC levels more frequently were being treated with an inappropriate low DOAC dose (29.4% vs 16.0%, p = 0.004), more frequently had unknown last DOAC intake or intake >48 h before admission (72.5% vs 57.5%, p = 0.004), and had higher baseline NIHSS (8 vs 4, p = 0.001). Lower DOAC levels were associated with large or medium vessel occlusion (LVO/MeVO; odds ratio per 10 ng/mL-increase = 0.89, 95% confidence interval = 0.85-0.94, p < 0.001). Cardiac pathology as the only potentially causal mechanism was more frequent in low DOAC levels patients (76.8% vs 60.6%, p = 0.029). Thirty patients (18.4%) had ⩾2 potentially causal mechanisms, 18 (11.0%) had potentially causal mechanisms other than cardiac pathology, and 5 (3.1%) had no identifiable potentially causal mechanism.

Conclusion

In DOAC-treated patients with ischemic stroke or TIA, low DOAC levels were found in 2/5 of patients. Lower DOAC levels are associated with increased stroke severity and the presence of LVO/MeVO. The profile of stroke etiology in DOAC-treated patients varies between groups with and without low DOAC levels.

SUBMITTER: Rust M 

PROVIDER: S-EPMC12901951 | biostudies-literature | 2026

REPOSITORIES: biostudies-literature