Which components of the CHA2DS2-VASc score are the most important in obstructive sleep apnea patients with atrial fibrillation?

Elevated thromboembolic risk is observed in patients with atrial fibrillation. The arrhythmia often co-exists with other diseases like obstructive sleep apnea (OSA), which adds to the thrombogenic profile and makes the proper assessment of thromboembolic risk difficult. The aim of the study was to establish how the prevalence of thromboembolic risk factors differs in patients with and without OSA. CHA2DS2-VASc score was used to assess thromboembolic risk in continuous atrial fibrillation patients prequalified for atrial fibrillation ablation. All 266 patients included in the study had a polygraphy examination. Patients were divided into a group with apnea-hypopnea index (AHI) <15/h, and those with AHI 15/h or above, who were considered as having OSA. The study population was aged 57.6 ± 10.1 years, and 65.0% of the subjects were male. OSA was diagnosed in 47 patients. In OSA patients, the following CHA2DS2-VASc risk factors had significantly higher prevalence: congestive heart failure (6.5 vs. 0.5%; P = 0.02), arterial hypertension (93.5 vs. 70.9%; P = 0.01), diabetes mellitus (26.1 vs. 6.8%; P = 0.003), and history of vascular disease (23.9 vs. 8.2%; P = 0.006) than in non-OSA patients. Nonsignificant differences were noticed in the history of stroke, age categories, or sex. After dividing patients into four groups, that is non-OSA, mild OSA, moderate OSA, and severe OSA the same risk factors as previously stated remained significant (P < 0.05). The strongest contributors, responsible for elevated thromboembolic risk observed in atrial fibrillation patients with OSA are congestive heart failure, arterial hypertension, diabetes mellitus, and vascular disease. Higher comorbidity burden is another argument for including OSA into the risk assessment schemes in atrial fibrillation patients.