Pre-procedural shunt characteristics and residual shunting at 6 months after percutaneous PFO closure

Purpose Contrast transthoracic echocardiography (cTTE) is used to assess the presence and size of a shunt in patients suspected of a patent foramen ovale (PFO), both during normal breathing and the Valsalva manoeuvre. The shunt pattern on cTTE, shunt at rest or shunt only during Valsalva, may reflect anatomical complexity and thereby influence the risk of residual shunting. This study aimed to determine whether pre-procedural shunt characteristics are associated with the presence of residual shunting at 6 months after percutaneous PFO closure. Methods In this retrospective cohort study, patients undergoing percutaneous PFO closure between 2005 and 2024 were included. Patients were divided in two groups based on the initial, pre-procedural cTTE, with group A consisting of patients with a spontaneous shunt and group B consisting of patients with a shunt that was only present during the Valsalva manoeuvre. The presence of any residual shunting between group A and B was compared using the Χ2-test. A multivariable logistic regression was performed to assess the association between shunt pattern and residual shunting at 6 months, correcting for pre-procedural shunt size (graded as small/medium/large based on cTTE) and size of the closure device. Results Of the included patients, 443 patients had available data of the pre-procedural cTTE and the primary outcome of residual shunting at 6 months. A residual shunt was present at 6 months in 37.7% of the patients in group A and 33.3% of the patients in group B (P = 0.41). In the multivariable logistic regression, adjusted for pre-procedural shunt size and device size, no association was observed between pre-procedural spontaneous shunting and residual shunting at 6 months (OR 1.22, 95% CI; 0.77-1.98). The pre-procedural shunt size was not associated with residual shunting, whereas a larger device size was independently associated (OR 1.17, 95% CI; 1.10-1.26). Conclusion In this study the pre-procedural shunt pattern and size were not associated with residual shunting at 6 months. The size of the closure device emerged as an independent predictor of residual shunting, suggesting the features of the closure device in relation to the surrounding structures may play a more prominent role in residual shunting than initial shunt characteristics.