Transoesophageal echocardiography with contrast bubble study directly after device placement to assess successful closure of PFO: a predictor for residual shunt at 6 months follow-up?

Abstract Background Pathology studies show that around 25% of the general population has a patent foramen ovale, which mostly remains asymptomatic. However, some patients suffer from cryptogenic stroke and in selected cases, percutaneous PFO closure is indicated to reduce the risk of recurrent stroke. At present, there is no consensus on the optimal timing to assess the presence of residual shunt after closure. Residual shunt is present in up to 25% of all patients and in case of a large residual shunt, may be associated with an increased risk of recurrent stroke. Purpose This study aims to investigate if residual shunt assessed directly after device placement is a predictor for residual shunt at 6 months follow-up. Methods In a single centre, we enrolled 101 patients between April 2023 and June 2024, that underwent PFO closure under transoesophageal echocardiography (TOE) guidance. We performed contrast bubble study with TOE after device placement and compared this with transthoracic echocardiography (TTE) with contrast bubble study at 6 months follow-up. Results The mean age was 48.1 years (SD ±10.7), 53.5% (54 patients) was female, the median RoPE-score was 6 IQR 6-7. Directly after device implantation, 34.7% (35 patients) had none residual shunt, 31.7% (32 patients) had small residual shunt, 9.9% (10 patients) had moderate residual shunt and 23.8% (24 patients) had large residual shunt. At 6 months follow-up with TTE, at rest, 40.6% (41 patients) had the same residual shunt grade compared to TOE, in 58.4% (59 patients) the residual shunt grade decreased and in 1.0% (1 patient) the residual shunt grade increased. With Valsalva manoeuvre this was 31.7% (32 patients), 42.6% (43 patients) and 25.7% (26 patients), respectively. The negative predictive value of TOE shunt assessment after device placement for residual shunt at 6 months follow-up at rest was 97.1% (34 out of 35 patients) and with Valsalva manoeuvre 62.9% (22 out of 35 patients). Our results indicate that 37.1% of patients with residual shunt at 6 months would be missed if there was no follow-up bubble testing with Valsalva planned in these patients. Conclusion This study shows that in patients without residual shunt at the end of the closure procedure, 37.1% shows any degree of residual shunt at 6 months follow-up, with 20.0% being moderate or large. Further research is needed to determine the optimal follow-up moment for residual shunt assessment.Figure 1. Figure 2.