Impact of Pre-Existing and Newly Diagnosed Atrial Fibrillation on Clinical Outcomes of Patients with Ischaemic Stroke Undergoing Endovascular Thrombectomy: Analysis of Local Data

Background: Atrial fibrillation (AF) is a major risk factor for ischaemic stroke (IS) and adverse long-term outcomes. The impact of pre-existing versus newly diagnosed AF on prognosis after endovascular thrombectomy (EVT) is uncertain. Methods: We conducted a retrospective analysis of patients with IS admitted to Mersey and West Lancashire Teaching Hospitals NHS Trust between January 2016 and November 2023 who underwent EVT. Data were extracted from the Sentinel Stroke National Audit Programme and cross-referenced with hospital medical records. Patients were categorised into three groups based on AF status: no-AF, pre-existing AF, and new-AF. Outcomes included prolonged hospital length of stay (LOS) ≥75th percentile, poor functional outcome (modified Rankin Scale mRS ≥ 3 at discharge), and all-cause mortality (in-hospital, at 30-day, and at 6-month mortality). Logistic regression and Cox proportional hazards models were used for analysis. Results: A total of 138 patients were included (mean ± SD for age: 67.9 ± 13.9 years; 45.7% female). Hospital LOS was longest in the new-AF group (median 35.0 days IQR: 6.0–53.0) compared with the pre-existing AF group (18.0 days 6.0–42.0), and the no-AF group (7.0 days 3.0–28.0), p = 0.024. In adjusted logistic regression, new-AF was significantly associated with prolonged LOS (OR = 2.55, 95%CI: 1.01–6.45, p = 0.048) but showed no association with poor functional prognosis (p = 0.851). Cox regression analysis showed that AF status was not associated with mortality (p = 0.325). Conclusions: Newly diagnosed AF after stroke is associated with prolonged hospitalisation despite comparable rates of successful EVT results but had no effect on functional prognosis or risk of death.