Association of incomplete device apposition with stroke recurrence after patent foramen ovale closure.

BACKGROUND: The mechanisms underlying stroke recurrence after patent foramen ovale (PFO) closure for secondary prevention remain poorly understood. This study evaluated incomplete device apposition (IDA) using cardiac CT angiography (CTA) and investigated its association with stroke recurrence. METHODS: In this prospective cohort study conducted at four centres in China (2020-2026), 233 patients (mean age: 37.01±6.73 years; 48.9% male) without known vascular risk factors were included from 382 consecutive candidates who underwent transcatheter PFO closure with follow-up ≥6 months. Cardiac CTA at 6 months post closure assessed the presence, location and extent of IDA defined as a gap between the left disc and the interatrial septum. Recurrent stroke and new-onset symptoms (atrial tachyarrhythmia, migraine headache, chest pain/discomfort) were recorded and their associations with IDA were analysed. RESULTS: IDA was observed in 55.8% of patients predominantly at the anterior-inferior rim (93.4%). IDA was significantly associated with larger and longer PFOs, larger devices and greater in vivo device thickness (p < 0.001 for all). During a median follow-up of 20.00 (IQR 18.00-24.00) months, patients with IDA had a higher risk of recurrent stroke (log-rank p = 0.022) and new-onset symptoms (log-rank p < 0.001). In eight patients who underwent repeat CTA, device apposition remained stable after 6-month closure. Pathological validation was available in one patient with severe chest pain/discomfort and a well-apposed device had sufficient endothelialisation. CONCLUSION: IDA is common after PFO closure and is associated with increased risks of recurrent stroke and new-onset symptoms. Preventive strategies warrant further investigation. TRIAL REGISTRATION NUMBER: NCT04686253.