Anticoagulation Reduces Risk of Stroke in Cervical Artery Dissection, With Effects Based on Timing

New data from the observational retrospective STOP-CAD study revealed the benefit of anticoagulation treatment over antiplatelets in reducing ischemic stroke risk, particularly with occlusive dissection, among patients with cervical artery dissection (CAD). Authors cautioned though that if anticoagulation is chosen as a treatment, patients should switch to antiplatelet therapy before 180 days to lower the risk of major bleeding.¹

Among 3636 patients with CAD in the study, 402 (11.1%) received exclusively anticoagulation and 2453 (67.5%) received exclusively antiplatelets. By day 180 of treatment with either anticoagulation or antiplatelets, investigators reported 162 new ischemic strokes (4.4%) and 28 major hemorrhages (0.8%). In total, 87.0% of experienced ischemic strokes occurred within 30 days of treatment. In adjusted Cox regression with adjusted Cox regression with Inverse Probability of Treatment Weighting (IPTW) analysis, investigators observed anticoagulation was associated with a nonsignificantly lower risk of subsequent ischemic stroke by day 30 (adjusted HR, 0.71; 95% CI, 0.45-1.12; P = .145) and by day 180 (adjusted HR, 0.80; 95% CI, 0.28-2.24; P = .670) compared with antiplatelet therapy.

Top Clinical Takeaways

Anticoagulation shows promise in lowering the risk of ischemic stroke, especially in cases of occlusive dissection, according to the STOP-CAD study.
Caution is advised when using anticoagulation, with a recommendation to switch to antiplatelet therapy before 180 days to mitigate the risk of major bleeding.
The study suggests a need for individualized treatment approaches based on the patient's risk of stroke and bleeding, acknowledging the limitations of retrospective observational studies.

“Based on these results, we would generally suggest that if any treatment is reasonable, and if a provider picks anticoagulation, then they should consider stopping anticoagulation by day 30 since that is where the majority of ischemic strokes happened in our study and in other studies as well,” lead author Shadi Yaghi, MD, associate professor of neurology, and division chief, vascular neurology, the Warren Alpert Medical School, Brown University, told NeurologyLive®. “We also found that patients with dissection and occlusion had a significant benefit from anticoagulation. In these patients, if it's safe to treat them with anticoagulation, then that would be preferred than antiplatelet therapy at least based on the results of our study.”

Presented at the 2024 International Stroke Conference (ISC), held February 7-9, in Phoenix, Arizona, investigators conducted a multicenter international study on patients with CAD without major trauma from 16 countries (sites, n = 63). The exposure used in the study was antithrombotic treatment type, anticoagulation compared with antiplatelets. The outcomes analyzed were subsequent ischemic stroke and major hemorrhage, intracranial or extracranial hemorrhage. Authors used adjusted IPTW to determine associations between anticoagulation and outcomes in 30 and 180 days. In the main analysis, authors used an “as treated” cross-over approach and only used outcomes that occurred with the included treatments.

“I think looking at the patient in general for the risk of stroke and bleeding would be very helpful for picking the right treatment for each patient. It may not be a one treatment for all approach, it may be more often individualized treatment based on the risk of stroke and the risk of bleeding,” Yaghi added.

Anticoagulation therapy was not associated with a higher risk of major hemorrhage by day 30 (adjusted HR, 1.39; 95% CI 0.35-5.45, p=0.637) but was by day 180 (adjusted HR, 5.56; 95% CI 1.53-20.13; P = .009). In the interaction analyses, patients with occlusive dissection had significantly lower ischemic stroke risk with anticoagulation (adjusted HR, 0.40; 95% CI, 0.18-0.88; Pinteraction= .009).

“Our study has several limitations. It's retrospective observational studies always confounding by indication bias. However, we used some robust methodology to try to mitigate the risk of bias. We did inverse probability weighting and propensity score matching. This would minimize the bias, but there may still be some residual confounding at a lot of our sites where large comprehensive stroke centers are which might not apply to smaller hospitals,” Yaghi added. “In addition, there was a lot of heterogeneity and anticoagulants that were used, and antiplatelets. This could have potentially affected our findings. I think this study brings us closer to an answer on which treatment is better for which patient.”

All told, the findings from the current study aligned with the data observed in the TREAT-CAD study which showed numerically fewer ischemic events with vitamin K antagonist anticoagulation compared with aspirin among patients with stroke.² Additionally, authors noted that a meta-analysis of the TREAT-CAD and CADISS trials revealed fewer ischemic strokes yet more frequent major bleeding events with anticoagulation.³ Yaghi et al noted that the findings of the current study provide evidence of nonsignificantly lower subsequent ischemic strokes but higher major hemorrhage risk in patients treated with anticoagulation.