Thrombolysis Safe for Stroke Patients on DOACs?

January 06, 2023

Stroke patients receiving thrombolysis do not appear to be an increased risk of symptomatic intracerebral hemorrhage (sICH) if they are taking direct oral anticoagulants (DOACs), a new study has found.

The study, the largest ever regarding the safety of thrombolysis in patients on DOACs, actually found a lower rate of sICH among patients taking DOACs than among those not taking anticoagulants.

"Thrombolysis is a backbone therapy in stroke, but the large population of patients who take DOACs are currently excluded from this treatment because DOAC use is a contraindication to treatment with thrombolysis. This is based on the presumption of an increased risk of sICH, but data to support or refute this presumption are lacking," the senior author of the current study, David J. Seiffge, MD, Bern University Hospital, Switzerland, told | Medscape Cardiology.

"Our results suggest that current guidelines need to be revised to remove the absolute contraindication of thrombolysis in patients on DOACs. The guidelines need to be more liberal on the use of thrombolysis in these patients," he added.

"This study provides the basis for extending vital thrombolysis treatment to this substantial population of patients who take DOACs," Seiffge said.

He estimates that 1 of every 6 stroke patients are taking a DOAC and that 1% to 2% of patients taking DOACs have a stroke each year. "As millions of patients are on DOACs, this is a large number of people who are not getting potentially life-saving thrombolysis therapy."

Seiffge comments: "In our hospital we see at least one stroke patient on DOACs every day. It is a very frequent scenario. With this new data, we believe many of these patients could now benefit from thrombolysis without an increased bleeding risk."

The study was published online in JAMA Neurology on January 3.

While thrombolysis is currently contraindicated for patients taking DOACs, some clinicians still administer thrombolysis to these patients. Different selection strategies are used, including the use of DOAC reversal agents prior to thrombolysis, or the selection of patients with low anticoagulant activity, the authors note.

The current study involved an international collaboration. The investigators compared the risk of sICH among patients who had recently taken DOACs and who underwent thrombolysis as treatment for acute ischemic stroke with the risk among control stroke patients who underwent thrombolysis but who had not been taking DOACs.

Potential contributing centers were identified by a systematic search of the literature based on published studies on the use of thrombolysis for patients who had recently taken DOACs or prospective stroke registries that may include patients who had recently taken DOACs.

The study included 832 patients from 64 centers worldwide who were confirmed to have taken a DOAC within 48 hours of receiving thrombolysis for acute ischemic stroke. The comparison group was made up of 32,375 patients who had experienced ischemic stroke that was treated with thrombolysis but who had received no prior anticoagulation therapy.

Compared with control patients, patients who had recently taken DOACs were older; the incidence of hypertension among them was higher; they had a higher degree of prestroke disability; they were less likely to be smokers; the time from symptom onset to treatment was longer; they had experienced more severe stroke; and they were more likely to have a large-vessel occlusion.

Of the patients taking DOACs, 30.3% received DOAC reversal prior to thrombolysis. For 27.0%, DOAC plasma levels were measured. The remainder were treated with thrombolysis without either of these selection methods.

Results showed that the unadjusted rate of sICH was 2.5% among patients taking DOACs, compared with 4.1% among control patients who were not taking anticoagulants.

After adjustment for stroke severity and other baseline sICH predictors, patients who had recently taken DOACs and who received thrombolysis had lower odds of developing sICH (adjusted odds ratio [OR], 0.57; 95% CI, 0.36 – 0.92; P = .02).

There was no difference between the selection strategies, and results were consistent in different sensitivity analyses.

The secondary outcome of any ICH occurred in 18.0% in patients taking DOACs, compared with 17.4% among control patients who used no anticoagulants. After adjustment, there was no difference in the odds for any ICH between the groups (adjusted OR, 1.18; 95% CI, 0.95 – 1.45; P = .14).

The unadjusted rate of functional independence was 45% among patients taking DOACs, compared with 57% among control patients. After adjustment, patients who had recently taken DOACs and who underwent thrombolysis had numerically higher odds of being functionally independent than control patients, although this difference did not reach statistical significance (adjusted OR, 1.13; 95% CI, 0.94 – 1.36; P = .20).

The association of DOAC therapy with lower odds of sICH remained when mechanical thrombectomy, large-vessel occlusion, or concomitant antiplatelet therapy was added to the model.

"This is by far the largest study to look at this issue of thrombolytic use in patients on DOACs, and we did not find any group on DOACs that had an excess ICH rate with thrombolysis," Seiffge said,

He explained that receiving warfarin was at one time an absolute contraindication for thrombolysis, but after a 2014 study suggested that the risk was not increased for patients with an international normalized ratio <117, this was downgraded to a relative contraindication.

"We think our study is comparable and should lead to a guideline change," Seiffge commented.

"A relative contraindication allows clinicians the space to make a considered decision on an individual basis," he added.

Seiffge said that at his hospital, local guidelines regarding this issue have already been changed on the basis of these data, and use of DOACs is now considered a relative contraindication.

"International guidelines can take years to update, so in the meantime, I think other centers will also go ahead with a more liberal approach. There are always some centers that are ahead of the guidelines," he added.

Although the lower risk of sICH seen in patients who have recently used DOACs seems counterintuitive at first glance, there could be a pathophysiologic explanation for this finding, the authors suggest.

They point out that thrombin inhibition, either directly or via the coagulation cascade, might be protective against the occurrence of sICH.

"Anticoagulants may allow the clot to respond better to thrombolysis ― the clot is not as solid as is easier to recanalize. This leads to smaller strokes and a lower bleeding risk. Thrombin generation is also a major driver for blood brain barrier breakdown. DOACs reduce thrombin generation, so reduce blood brain barrier breakdown and reduce bleeding," Seiffge explained. "But these are hypotheses," he added.

Study "Meaningfully Advances the Field"

In an accompanying editorial, Eva A. Mistry, MBBS, University of Cincinnati, Ohio, says the current study "meaningfully advances the field" and provides an estimation of safety of intravenous thrombolysis among patients who have taken DOACs within 48 hours of hospital admission.

She lists strengths of the study as inclusion of a large number of patients across several geographically diverse institutions with heterogeneous standard practices for thrombolysis with recent DOAC use and narrow confidence intervals regarding observed rates of sICH.

"Further, the upper bound of this confidence interval for the DOAC group is below 4%, which is a welcome result and provides supportive data for clinicians who already practice thrombolysis for patients with recent DOAC ingestion," Mistry adds.

However, she points out several study limitations, which she says limit immediate, widespread clinical applicability.

These include use of a nonconcurrent control population, which included patients from centers that did not contribute to the DOAC group and the inclusion of Asian patients who likely received a lower thrombolytic dose.

Seiffge responded that they did adjust for Asian patients but not for the thrombolytic dosage. "I personally do not think this affects the results, as Asian patients have a lower dosage because they have a higher bleeding risk. The lower bleeding risk with DOACs was seen in all continents."

Mistry also suggests that the DOAC group itself is prone to selection bias from preferential thrombolysis of patients receiving DOAC who are at lower risk of sICH.

But Seiffge argued: "I think actually the opposite is true. The DOAC patients were older, had more severe comorbidities, and an increased bleeding risk."

Mistry concludes, "Despite the limitations of the study design and enrolled population, these data may be used by clinicians to make individualized decisions regarding thrombolysis among patients with recent DOAC use. Importantly, this study lays the foundation for prospective, well-powered studies that definitively determine the safety of thrombolysis in this population."

The study was supported by a grant from the Bangerter-Rhyner Foundation. Seiffge received grants from Bangerter Rhyner Foundation during the conduct of the study and personal fees from Bayer, Alexion, and VarmX outside the submitted work. Mistry receives grant funding from the National Institute of Neurological Disorders and Stroke and serves as a consultant for RAPID AI.

JAMA Neurol. Published online January 3, 2023. Full text, Editorial

For more from the | Medscape Cardiology, follow us on Twitter and Facebook.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.