Atrial fibrillation (AFib) patients who are not treated with oral anticoagulants (OAC) due to a high risk of bleeding are at risk of ischemic and hemorrhagic events, according to a study published September 27 in the journal JACC: Clinical Electrophysiology.

Björn Redfors, MD, PhD, et al., identified 43,251 AFib patients who had no evidence of OAC or low molecular heparin use. More than four out of five patients with OAC contraindications had a CHADS2-VASc score greater than one and 42.9 percent had a CHADS2-VASC-score of at least four. Patients who experienced an event were older than patients who did not and were more likely to previously have had an ischemic stroke, transient ischemic attack or myocardial infarction. They were also more likely to have high CHADS2 and CHADS2-VASc scores.

The incidence of ischemic stroke was 4.1 percent in the overall study cohort and was 12.2 percent among patients with a previous cerebral or intracranial hemorrhage. Hemorrhagic stroke was almost as common as ischemic stroke in this population. The incidence of ischemic stroke increased with increasing CHADS2 or CHADS2-VASc scores in the overall study population and was consistent with current reference rates for a general population of AFib patients. The risk of major bleeding also increased with increasing CHADS2-VASc scores and was considerably higher than in an OAC-treated general population of AFib patients.

The results show that a considerable number of patients with AFib do not receive any anticoagulation therapy despite the fact that the majority of them have CHADS2 and CHADS2-VASc scores consistent with a high risk of ischemic stroke. The risk of both bleeding complications and thromboembolic events were particularly high in patients who previously had a hemorrhagic stroke.

“Our data show that this subset of patients would benefit greatly from alternative methods of stroke prevention that do not impose an increased bleeding risk,” the authors wrote.