According to a new study from UT Southwestern Medical Center, the majority of stroke patients taking the anticoagulant warfarin were no more likely than those not taking the medication to have a brain bleed during a procedure to remove a blood clot. The discoveries, distributed in JAMA, could assist doctors with better measuring the risk of endovascular thrombectomy (EVT), possibly extending the pool of qualified patients for this pillar stroke treatment.
“Warfarin is a type of blood thinner that is frequently prescribed to patients with heart conditions like atrial fibrillation to prevent strokes. Albeit not extremely normal, patients taking warfarin might, in any case, encounter a stroke. Because patients have been treated with warfarin prior to their strokes, it is very possible for some physicians to withhold an endovascular thrombectomy in clinical practice.
According to study leader Ying Xian, M.D., Ph.D., Associate Professor of Neurology at the Peter O’Donnell Jr. School of Public Health at UT Southwestern, “our study could increase the number of patients for whom this lifesaving and function-saving surgery would be appropriate.” Dr. Xian is additionally Segment Head of Exploration, Stroke, and Cerebrovascular Illnesses in the Division of Nervous System Science at UTSW.
“Our research could increase the number of patients who would benefit from this life-saving and function-saving surgery,”
Study leader Ying Xian, M.D., Ph.D., Associate Professor of Neurology .
The Centers for Disease Control and Prevention estimate that nearly 800,000 Americans suffer from strokes each year. The majority of these strokes are ischemic, which means that a blood clot prevents blood flow to a specific area of the brain.
The most common treatment for acute ischemic stroke is EVT, a surgery in which instruments are threaded through the blood vessels to break up the clot. However, Dr. Xian explained that EVTs can occasionally result in symptomatic intracranial hemorrhage (sICH), a potentially fatal brain bleed. Although warfarin is known to increase the risk of bleeding, it is unknown whether stroke patients on blood thinners are more likely to experience sICH after EVT.
Dr. Xian collaborated with colleagues from other medical institutions across the country, as well as Professor of Internal Medicine and Vice Provost for Clinical Research at UTSW Eric Peterson, M.D., M.P.H., to assist in answering this question. Between 2015 and 2020, they collected information on 32,715 stroke patients who underwent EVT within six hours of experiencing stroke symptoms. Information came from the American Heart Association’s Get with the Rules Stroke Library—tthe biggest vault of stroke patients on the planet.
The outcomes of the 3,087 patients who took warfarin before a stroke and the 29,628 patients who did not take any blood thinner were compared by the researchers. They looked at whether patients had sICH within 36 hours of their EVT procedure, a serious systemic hemorrhage, or other complications that necessitated additional medical care or a prolonged stay in the hospital. In addition, complications from additional therapies that reintroduced blood flow to the brain, in-hospital deaths, and admissions to hospice care were monitored by the researchers.
The researchers discovered that there was no difference in the overall risk of sICH or other adverse outcomes between patients in these two groups after accounting for the inherent differences between patients taking and not taking warfarin. However, the risk of sICH increased by approximately 4% in patients with an international normalized ratio (INR) greater than 1.7, which is a measure of blood clotting tendency in warfarin patients.
Dr. Peterson stated that it is unclear whether this effect leads to patients having worse outcomes. These patients had no higher risk of death or worse functional outcomes at discharge than those who did not take warfarin, with the exception of a higher risk of bleeding.
“Our study suggests that taking warfarin alone should not necessarily be a limiting factor,” he added. “Physicians must evaluate stroke patients on a case-by-case basis to determine whether EVT is appropriate.”
Drs. According to Xian and Peterson, they intend to investigate the possibility of an increase in the risk of sICH or other serious complications following EVT for ischemic stroke in patients who take other anticoagulants frequently.
More information: Brian Mac Grory et al, Recent Vitamin K Antagonist Use and Intracranial Hemorrhage After Endovascular Thrombectomy for Acute Ischemic Stroke, JAMA (2023). DOI: 10.1001/jama.2023.8073
