A new study in JAMA offers good news for the roughly two million Americans taking vitamin K antagonists (VKAs): VKAs do not appear to increase risk for complications from endovascular thrombectomy (EVT), a lifesaving form of “keyhole surgery” used to treat the most common form of stroke. These findings help to validate the low risk of EVT for a large proportion of the population that is already at risk for stroke.
“EVT rewrote the book on stroke treatment. It greatly reduces or even eliminates the devastating lifelong injuries left behind after stroke,” said Brian Mac Grory, MB BCh, MRCP, a vascular neurologist at Duke and first author of the study. “It is incredibly satisfying to know that this procedure can be deployed effectively in this large, vulnerable population. Although observational studies like this have to be interpreted with caution, it at least appears that doctors are effectively selecting those patients with an appropriate risk level for this procedure.”
Vitamin K antagonists, the most common forms of which are warfarin or coumadin, act as “blood thinning” medications. They disrupt the body’s ability to produce vitamin K, an essential component in blood clotting. These medications are commonly prescribed to people with irregular heartbeats, artificial heart valves, or clots in the legs to reduce the chance of clots that could get lodged in critical blood vessels in the brain or chest.
Strokes can be caused either when clots (ischemic strokes) or internal bleeding (hemorrhagic strokes) cause damage to a portion of the brain. Ischemic strokes--those caused by clots--make up about 87 percent of all strokes in the United States, while hemorrhagic strokes make up the rest. EVT has greatly reduced the rates for death and disability from ischemic stroke among the general population, but evidence has been lacking as to whether the procedure might trigger a hemorrhagic, or bleeding stroke, in patients already taking VKAs.
For the study, Mac Grory and colleagues examined outcomes of more than 32,000 ischemic stroke patients from a national registry, comparing rates of intracranial hemorrhage from patients taking VKAs to otherwise similar patients who were not. The proportions of intracranial hemorrhage were similar between the two groups, indicating that VKAs did not appear to cause brain bleeds. While those patients with a therapeutic INR had an elevated risk of bleeding, on balance there was no evidence of worsened harm in terms of survival or disability in this group.
In addition to offering guidance for clinicians treating stroke patients, the results of this study set the stage for further research examining EVT for patients taking other blood-thinning medications, said Ying Xian, MD, PhD, an academic researcher at UT Southwestern and the senior author of the study.
“In addition to VKAs, a newer form of blood thinners known as direct oral anticoagulants (or DOACs) are becoming an increasingly common treatment for people with irregular heartbeats, blood clots, who have had a stroke, or are at risk,” Xian said. “Examining the safety of EVT for patients taking DOACs, while also further validating the safety for EVT for patients taking VKAs, could greatly expand treatment options for stroke patients.”
This study is supported by the Addressing Real-world Anticoagulant Management Issues in Stroke (ARAMIS) registry which is sponsored by Daiichi Sankyo, Genentech, and Janssen.
In addition to Mac Grory and Xian, authors of the study include DaJuanicia Holmes, MS2; Roland Matsouaka, MD, Shreyansh Shah, MD; Cherylee Chang, MD; Richard Rison, MD; Jenelle Jindal, MD; Christine Holmstedt, DO; William Logan,; Candy Corral, RN; Jason Mackey, MD; Joey Gee, DO; David Bonovich, MD; James Walker, MD; Toby Gropen, MD; Curtis Benesch, MD; Jonathan Dissin, MD; Hemant Pandey, MD; David Wang, DO, Martin Unverdorben, MD, PhD; Adrian Hernandez, MD; Mathew Reeves, PhD; Eric Smith, MD, MPH; Lee Schwamm, MD; Deepak Bhatt, MD, MPH; Jeffrey Saver, MD; Gregg Fonarow, MD; and Eric Peterson, MD, MPH; Ying Xian, MD.