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Recurrence rate after warfarin resumption differs by stroke type

When recommending resuming warfarin following a stroke, clinicians should consider that patients with atrial fibrillation who resumed warfarin after hemorrhagic stroke had a higher rate of recurrence than patients with traumatic intracranial hemorrhage, according to research published in JAMA Internal Medicine.

“The increase in the risk for bleeding associated with antithrombotic therapy causes a dilemma in patients with atrial fibrillation (AF) who sustain an intracranial hemorrhage (ICH),” Peter Brønnum Nielsen, PhD, from the department of clinical medicine at Aalborg University in Denmark, and colleagues wrote. “A thrombotic risk is present; however, a risk for serious harm associated with resumption of anticoagulation therapy also exists.”

There is limited evidence on the benefits and harms of resuming warfarin in patients with AF who sustain an intracranial hemorrhage, according to the researchers. Therefore, they conducted a nationwide observational cohort study of 2,415 patients (1,481 men [61.3%]; mean age, 77.1 years) to determine the prognosis associated with resuming warfarin treatment stratified by the type of ICH — hemorrhagic stroke or traumatic ICH. Participants included those with AF who experienced an incident ICH event during warfarin treatment between Jan. 1, 1998 and Feb. 28, 2016 and completed follow-up by Apr. 30, 2016. The researchers assessed resumption of warfarin treatment after patients were discharged from the hospital.

Of the 2,415 patients, 1,325 had a hemorrhagic stroke and 1,090 had a traumatic ICH. Data indicated that 305 patients in the hemorrhagic stroke group (23%) died during the first year, as did 210 in the traumatic ICH group (19.3%). Compared with patients in the hemorrhagic stroke group who did not resume warfarin therapy, those who did resume treatment had a lower rate of ischemic stroke or systemic embolism (adjusted HR = 0.49; 95% CI, 0.24-1.02) and an increased rate of recurrent ICH (aHR = 1.31; 95% CI, 0.68-2.5); however, these differences were not statistically significant.

Warfarin therapy resumption among patients with traumatic ICH also led to a lower rate of ischemic stroke or systemic embolism (aHR = 0.4; 95% CI, 0.15-1.11). However, compared with patients in the hemorrhagic stroke group, those in the traumatic ICH group who resumed warfarin therapy had a significantly lower rate of recurrent ICH (aHR = 0.45; 95% CI, 0.26-0.76). Resuming warfarin therapy was associated with a decline in mortality among patients with hemorrhagic stroke (aHR = 0.51; 95% CI, 0.37-0.71) and traumatic ICH (aHR = 0.35; 95% CI, 0.23-0.52).

“Spontaneous hemorrhagic stroke and trauma-induced ICH confer different prognoses in patients with AF, and recommendations on resumption of warfarin treatment should consider this difference,” Nielsen and colleagues concluded. “Warfarin treatment resumption after a spontaneous hemorrhagic stroke event was associated with a lower rate for subsequent ischemic events, whereas the relative risk for recurrent ICH was increased; however, statistical uncertainty precludes firm conclusions of excess harm associated with treatment. Resumption of [oral anticoagulant] therapy in patients with traumatic ICH was associated with a lower rate of ischemic events and a lower relative risk for recurrent ICH despite resumption of warfarin treatment. In both groups, warfarin resumption was associated with a lower risk for death within the first year after the event.”

At last year's Cardiometabolic Health Congress, one expert argued that warfarin remains the safe and effective gold standard for patients with AF, while another said newer oral anticoagulants should be used. – by Alaina Tedesco

Disclosure: The researchers report support from an unrestricted grant from the Obel Family.