ABSTRACT NUMBER: ESOC2026A983 POSITIONAL OBSTRUCTIVE SLEEP APNEA IS A PREDOMINANT PHENOTYPE IN ACUTE ISCHEMIC STROKE: ASSOCIATIONS WITH DISEASE SEVERITY AND IMPLICATIONS FOR MANAGEMENT

Abstract Background and aims Obstructive sleep apnea (OSA) is highly prevalent during the acute phase of ischemic stroke and is associated with adverse neurological outcomes. Supine positioning is common after stroke and may exacerbate respiratory events. Positional OSA (POSA) represents a potentially modifiable phenotype, but its characteristics in the acute stroke setting remain insufficiently described. Methods We prospectively studied 125 acute ischemic stroke patients using bedside respiratory polygraphy. Patients with >90% supine sleep time (n=30) were excluded from positional phenotype classification due to insufficient non-supine sleep for reliable comparison. POSA was defined as OSA with a supine apnea–hypopnea index (AHI) at least twice the non-supine AHI. Clinical and sleep characteristics were compared between POSA and non-positional OSA groups. Results Mean age was 59.7±11.7 years, 69.5% were male, and median NIHSS was 3 (IQR 2–5). Of 95 eligible patients, 87 (91.6%) had OSA, of whom 69 (79.3%) met criteria for POSA. POSA prevalence was inversely related to OSA severity, ranging from 92.3% in mild OSA to 52.2% in severe OSA (p=0.001 for trend). Patients with POSA had significantly lower overall AHI compared to non-positional OSA (19.4±13.5 vs. 41.6±26.1 events/h; p=0.002). POSA status was not associated with anthropometric measures. Conclusions POSA is the dominant phenotype among acute ischemic stroke patients with OSA, particularly in those with mild-to-moderate OSA. Since prolonged supine positioning is common in acute stroke, even in patients with mild deficits, the high prevalence of POSA suggests that positional therapy could be an effective, targeted intervention. Conflict of interest Tho Phung: nothing to disclose Hoai-Thi-Thu Nguyen: nothing to disclose Giap Vu: nothing to disclose