Incidence, predictive factors, and prognostic impact of residual shunt after percutenous patent foramen ovale closure

Percutaneous closure of patent foramen ovale (PFO) is indicated for secondary prevention for cryptogenic stroke (CS) in patients under 60 years of age. Despite high technical success of the procedure, residual shunt (RS) has been reported but its incidence, predictive factors, and its long-term influence on stroke recurrence stay on topic debated. The aim of the study was to investigate the incidence of RS six months after percutaneous closure of PFO, its evolution at one-year, predictive factors, and its influence on stroke recurrence. Between February 2013 and October 2021, 174 patients underwent percutaneous closure of PFO in our institution for CS. Clinical, echographic, and procedural characteristics were recorded in a dedicate retrospective database. RS was prospectively evaluated by transthoracic echocardiography (TTE) with saline contrast (at rest and if necessary after Valsalva maneuver) at 6 month and at one year when RS was observed at 6 months. Stroke recurrence was estimated by medical records. Among our cohort of 174 patients, 158 (90.8%) underwent TTE with saline solution at six months. Thirty-one (19.6%) patients had a RS. Eight (5%) patients had a small RS (< 20 bubbles) and 23 (13%) patients had a significant shunt (> 20 bubbles). Seventeen patients with a RS at six months underwent TTE at one year. Three (17.6%) patients had no more RS. The only predictive factor of RS at 6 months was the presence of a right-to-left shunt after saline solution at rest (without it being necessary to unmask it by a valsalve maneuver) before PFO closure (P = 0.005). In contrast, the presence of atrial septal aneurysm, length of PFO tunel, and the size of the prosthesis used were not significatively associated with RS. After a mean follow-up of 24 ± 18months, one patient, without RS, had a recurrent stroke 10 months after PFO closure (related to an antiphospholipid antibody syndrome diagnosis), and one patient with RS had a transient ischemic attack (TIA) 14 months after PFO closure. RS after percutaneous PFO closure is not rare and was observed in 19.6% of cases at 6 months. The incidence may decrease overtime in some cases suggested delayed re-endothelialization of the prosthesis. Detection of PFO at rest before PFO closure, without the need of Valsalva maneuver, was the only predictive factor of RS. Recurrence of stroke or TIA after PFO closure was infrequent (1.1%) and not necessarily related to RS.