Direct oral anticoagulants are less likely to cause major bleeding after a rare fatal stroke
Direct oral anticoagulants (anti-clotting) (DOACs), which target a single clotting factor, work just as well to prevent future clots as the older, less specific drug warfarin. DOACs are also less likely to cause major bleeding after a rare, life-threatening stroke in which a clot blocks one of the veins that drain blood from the brain, according to preliminary latest findings presented today at the American Stroke Association’s 2022 International Stroke Conference , a world-leading gathering for researchers and clinicians dedicated to the science of stroke and brain health, taking place February 9-11, 2022 in New Orleans in person and virtually.
Cerebral venous thrombosis (CVT) stroke is rare but potentially life-threatening and more common than other types of stroke in younger adults and women.
Taking birth control pills and having recently given birth are two major risk factors for CVT, so CVT is probably more common in women.”
Shadi Yaghi, MD, lead author of the study, associate professor of neurology and chief of the division of vascular neurology at Warren Alpert Medical School at Brown University in Providence, Rhode Island
When CVT is diagnosed, standard immediate treatment includes administration of intravenous or injectable anticoagulants such as enoxaparin or heparin to dissolve the clot and restore blood flow. Oral anticoagulants are later prescribed to prevent another clot from forming so that there is continued adequate blood flow through the veins. If a transient factor (such as birth control pills or a recent birth) is suspected to have triggered the CVT, oral anticoagulants are usually prescribed for several months. If the patient has a lifelong serious medical condition that increases the risk of recurring blood clots, anticoagulant medications are usually prescribed indefinitely.
Newer and more specific anticoagulant drugs, called DOACs, have previously been compared to warfarin for the treatment of several other conditions, including atrial fibrillation (a common arrhythmia that’s a major risk factor for clot-related stroke) and leg and lung clots. DOACs have been found to work just as well in preventing blood clots from recurring, with less likelihood of the serious adverse effect of cerebral hemorrhage. After a small, randomized study suggested that a DOAC called dabigatran might be as effective as warfarin after CVT, researchers conducted a multicenter review comparing six years of real-world experience with warfarin or one of the DOACs for patients with CVT .
Researchers examined the medical records of 1,025 people treated for CVT at one of 27 centers in the United States, Europe and New Zealand between 2015 and 2020. The analysis excluded patients who had cancer, antiphospholipid antibody syndrome (an acquired condition that increases the risk of clotting), or who were not prescribed oral anticoagulants.
Of the 845 participants in the final analysis (mean age 44.8 years; 64.7% women), 33% were prescribed only one DOAC; 51.8% were only prescribed warfarin; and 15.1% were prescribed both treatments at different times.
During a mean follow-up of 345 days, the researchers calculated that there were 5.68 recurrent venous clots, 3.77 major bleeds and 1.84 deaths per 100 patient-years. Compared to participants treated with warfarin, participants treated with DOACs had:
- a similar risk of recurrent venous clots and death and
- a 65% reduced risk of major bleeding anywhere in the body.
When considered separately, the incidence of cerebral hemorrhage per 100 patient-years was much lower in patients prescribed DOACs than in patients prescribed warfarin (1.52 vs. 3.51), while the occurrence of major non-cerebral hemorrhages was similar (0.91 vs. 1.15).
Imaging of the areas involved in CVT was compared between the two treatment types for 525 participants, excluding those whose blood clots were treated surgically, those who did not have follow-up imaging after oral anticoagulation was started, and those who had adequate blood already through their veins are flowing before they start oral anticoagulants. Analysis found that among participants who prescribed DOACs:
- Veins were fully patent in 36.6% of participants, partially patent in 48.2%, and remained occluded in 15.2%; and
- They were just as likely to have partially or fully dilated veins compared to the participants who were prescribed warfarin.
The results were adjusted for age, gender and relevant diseases.
“These results, using real-world data, suggest that direct oral anticoagulants are as effective as warfarin in reducing the likelihood of recurring blood clots and increasing the likelihood of recanalization (complete or partial dissolution of the clot leading to the opening of the vein leads). and they have a reduced risk of major bleeding,” said Yaghi, who is also co-director of the Comprehensive Stroke Center at Rhode Island Hospital in Providence. “Both DOACS and warfarin are viable options for treating CVT patients, especially with warfarin the risk of bleeding is rather low.”
The limitations of the study include that it is a retrospective analysis, so the authors state that the results should be interpreted with caution pending confirmation from large, ongoing, prospective, or randomized studies.
American Heart Association