From the Journals

Is thrombolysis safe for stroke patients on DOACs?


 

From JAMA Neurology

Stroke patients receiving thrombolysis do not appear to be at 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,” said senior author David J. Seiffge, MD, Bern University Hospital, Switzerland.

“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,” Dr. 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.”

Dr. 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.

An international investigation

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 noted.

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, 0.57; 95% confidence interval, 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 (aOR, 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 (aOR, 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,” Dr. 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 below 117, this was downgraded to a relative contraindication.

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

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

Dr. 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 and 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,” Dr. Seiffge explained. “But these are hypotheses,” he added.

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