Device-related thrombus after percutaneous intervention for Atrial Septal Defect (ASD) and Patent Foramen Ovale (PFO)

Abstract Background Thrombotic formations on occluder devices following interventional, catheter-based closure of atrial septal defect (ASD) and patent foramen ovale (PFO) are a potentially severe complication. These formations can be detected via transesophageal echocardiography (TEE) during follow-up visits. Since occluder-associated thrombotic formations appear to be rare and clinical experience suggests a higher incidence in patients undergoing ASD occlusion, we assessed this complication in a large cohort of patients undergoing TEE as part of a routine follow up visit after ASD/PFO occluder implantation with the aim to reevaluate the clinical necessity of a TEE in this setting. Secondary endpoints included residual shunt and device malposition. Hypothesis Thrombotic formations on occluder devices detected during follow-up TEE are rare, with a significantly lower incidence in PFO-patients compared to ASD-patients. Patients and Methods For this monocentric, retrospective study, we conducted a keyword search in our departmental database for 'ASD,' 'PFO,' and 'occluder' across all cath lab reports from 2004 to 2023, identifying 1,253 cases. Of these, 985 met the inclusion criteria of having undergone interventional closure of either an ASD or a PFO and a TEE examination performed 1 to 12 months post-intervention. Results The mean age of the population under study was 52 ± 13 years, and 50.1% were female. In the ASD group (n=249), a thrombotic formation was detected in three patients (cumulative incidence: 1.2%; 95% CI: 0.3%–3.2%), whereas no cases were found in the PFO group (n=736, p = 0.003). A residual shunt categorized as 'medium' or 'large' in at least one echocardiographic method was reported in 2.4% (95% CI: 1.0%–4.9%) of ASD patients and 2.9% (95% CI: 1.8%–4.2%) of PFO patients (p = 0.711, Figure). A device malposition/unstable device fit was documented in 0.4% (95% CI: 0.0%–1.9%) of ASD patients and 0.1% (95% CI: 0.0%–0.6%) of PFO patients (p = 0.414). Conclusion Device-related thrombus formation after ASD and PFO closure is rare, with no thrombi detected in a large cohort of PFO patients. Since in addition, the incidence of significant residual shunts was low in both groups the routine use of TEE during follow-up visits, particularly in PFO patients, may be reconsidered. Further studies are needed to refine follow-up strategies and determine which patients would benefit most from continued transesophageal echocardiographic monitoring.Incidence and magnitude residual shunt