Prevalence, determinants, and impact of significant shunt after percutaneous patent foramen ovale closure

Abstract Introduction Percutaneous closure of patent foramen ovale closure is increasingly performed for secondary prevention of PFO-related arterial embolic event. The clinical significance of postclosure residual right-to-left significant shunt remains unclear. Purpose To describe the prevalence, determinants, and clinical impact of a significant post-closure. Methods The AIR-FORCE is an ongoing prospective international registry of patients undergoing PFO closure from 19 centers in France, Canada and Italy. Only patients undergoing PFO for secondary prevention of an arterial embolic event with at least one available post-closure contrast transthoracic echocardiography (TTE) with agitated saline injection and Valsalva maneuvers were analyzed. Residual shunt was categorized according to the number of bubbles in the left atrial within 3 cardiac cycles at the first available contrast TTE as small (<10), moderate (10-20) or severe (> 20). Determinants of the presence of moderate or severe shunt were evaluated with multivariate logistic regression and its impact on the primary outcome (stroke, transient ischemic attack or peripheral arterial emboly) was evaluated with Cox model adjusted on age and sex. Results A total of 2413 patients, with a median age of 49.3 [40.4-57.4] years, 56% male, undergoing PFO closure between 2001 and 2023 were included. The first contrast TTE, which was performed after a median delay of 3.4 [0.9-5.8] months, reported the presence of moderate or severe residual shunt in 214 (8.9% 95%CI 7.8-10.1) patients. Determinants of the presence of moderate or severe residual shunt at the first contrast TTE were decreased body mass index (per 1kg/m², aOR 0.96 95%CI 0.93-0.99), severe shunt prior to PFO closure (aOR 3.54 95%CI 2.25-5.55) and increased device left disc diameter (per 1mm, aOR 1.08 95%CI 1.05-1.12). With a median follow-up of 2.2 [0.9-4.9] years, a total of 60 events were reported and the presence of moderate or severe residual shunt was associated with an increased risk of the primary outcome (aHR 2.46 95%CI 1.15-5.24) (Figure 1). Conclusions A moderate to severe residual right-to-left intracardiac shunt is not uncommon after PFO percutaneous closure and seems to be associated with an increased risk of arterial emboly recurrence.