Are patients with embolic stroke of undetermined source more likely to benefit from rivaroxaban compared with aspirin if they are at a greater risk of having atrial fibrillation?
This secondary analysis of a randomized clinical trial examined 7112 patients who were stratified by clinical predictors of atrial fibrillation, left atrial diameter, and frequency of premature atrial contractions. In the predefined subgroup of patients with a left atrial diameter of more than 4.6 cm, there was a significant reduction in recurrent stroke among patients who had been treated with rivaroxaban.
Rivaroxaban appears to modestly reduce recurrent stroke in a small subgroup of patients with embolic stroke of undetermined source and moderate to severe left atrial enlargement.
The NAVIGATE ESUS randomized clinical trial found that 15 mg of rivaroxaban per day does not reduce stroke compared with aspirin in patients with embolic stroke of undetermined source (ESUS); however, it substantially reduces stroke risk in patients with atrial fibrillation (AF).
To analyze whether rivaroxaban is associated with a reduction of recurrent stroke among patients with ESUS who have an increased risk of AF.
Design, Setting, and Participants
Participants were stratified by predictors of AF, including left atrial diameter, frequency of premature atrial contractions, and HAVOC score, a validated scheme using clinical features. Treatment interactions with these predictors were assessed. Participants were enrolled between December 2014 and September 2017, and analysis began March 2018.
Rivaroxaban treatment vs aspirin.
Main Outcomes and Measures
Risk of ischemic stroke.
Among 7112 patients with a mean (SD) age of 67 (9.8) years, the mean (SD) HAVOC score was 2.6 (1.8), the mean (SD) left atrial diameter was 3.8 (1.4) cm (n = 4022), and the median (interquartile range) daily frequency of premature atrial contractions was 48 (13-222). Detection of AF during follow-up increased for each tertile of HAVOC score: 2.3% (score, 0-2), 3.0% (score, 3), and 5.8% (score, >3); however, neither tertiles of the HAVOC score nor premature atrial contractions frequency impacted the association of rivaroxaban with recurrent ischemic stroke (P for interaction = .67 and .96, respectively). Atrial fibrillation annual incidence increased for each tertile of left atrial diameter (2.0%, 3.6%, and 5.2%) and for each tertile of premature atrial contractions frequency (1.3%, 2.9%, and 7.0%). Among the predefined subgroup of patients with a left atrial diameter of more than 4.6 cm (9% of overall population), the risk of ischemic stroke was lower among the rivaroxaban group (1.7% per year) compared with the aspirin group (6.5% per year) (hazard ratio, 0.26; 95% CI, 0.07-0.94; P for interaction = .02).
Conclusions and Relevance
The HAVOC score, left atrial diameter, and premature atrial contraction frequency predicted subsequent clinical AF. Rivaroxaban was associated with a reduced risk of recurrent stroke among patients with ESUS and moderate or severe left atrial enlargement; however, this needs to be independently confirmed before influencing clinical practice.
Healey JS, Gladstone DJ, Swaminathan B, et al. Recurrent Stroke With Rivaroxaban Compared With Aspirin According to Predictors of Atrial Fibrillation: Secondary Analysis of the NAVIGATE ESUS Randomized Clinical Trial. JAMA Neurol. Published online April 08, 201976(7):764–773. doi:10.1001/jamaneurol.2019.0617
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