AF patients with VTE history at high risk of stroke, systemic embolism

The risk of ischaemic stroke or systemic embolism is comparable between atrial fibrillation (AF) patients with and without previous venous thromboembolism (VTE), a study has found. However, AF patients with previous VTE remain vulnerable due to an excess risk for future VTE.

This nationwide cohort study included 246,313 patients with incident AF from 2000–2017, defined and characterized using Danish health registries. The investigators performed Cox regression analyses to calculate hazard ratios (HRs) and 95 percent confidence intervals (CIs) for the outcomes of ischaemic stroke, systemic embolism, or VTE, according to VTE history. Analyses were adjusted for components of the CHA₂DS₂-VASc score and time-varying use of oral anticoagulation.

Of the patients with incident AF, 6,516 (2.6 percent) had previous VTE. Overall, the adjusted risk of ischaemic stroke or systemic embolism was similar between patients with previous VTE and those without (HR, 0.99, 95 percent CI, 0.90–1.09). Analysis of a composite thromboembolic outcome of ischaemic stroke, systemic embolism or VTE showed that patients with previous VTE remained at increased risk (HR, 1.76, 95 percent CI, 1.64–1.90).

Such findings persisted when stratifying by VTE subtype and when restricting to those with low CHA₂DS₂-VASc scores or the nonanticoagulated subset of the study population.

“Patients and physicians should keep this excess thromboembolic risk in mind when weighing the expected risks and benefits of oral anticoagulation in patients with AF,” the investigators said.