Size of transcatheter patent foramen ovale closure device affects atrial function
Authors: Molnar AA , Abraham P , Gulyas G , Meszaros H , Pasztor D , Straub E , Nardai S , Merkely B 
Published: February 2022

Abstract

Funding Acknowledgements
Type of funding sources: None.

Introduction
Interatrial communications such as patent foramen ovale (PFO) are common abnormalities. For most people they are accidental findings; however, in some cases lead to paradoxical embolization. Transcatheter closure of PFO in patients with cryptogenic stroke is associated with reduced rates of recurrent stroke. The size of closure device is established according to anatomical features of atria. However, the impact of atrial septal closure on atrial remodelling is less known.

Methods
We prospectively enrolled 108 patients with cryptogenic ischemic stroke and PFO eligible for transcatheter PFO closure. Thirty-three patients had 6 month clinical follow-up examinations (mean age 46 ± 13 years, 34% females). National Institute of Health Stroke Score (NIHSS) was calculated as marker of clinical severity of the index stroke. Presence of any shunt, atrial volumes and functional parameters were evaluated including left atrial (LA) reservoir, conduit and contraction function before PFO closure and 6 months after procedure. Beyond conventional transthoracic echocardiography (Philips Epiq CVx Ultrasound), two dimensional speckle tracking method was used to assess body surface area-indexed LA maximal volume (LAVmaxi), LA minimal volume (LAVmini), LA volume before left atrial contraction (LApreAi), LA ejection fraction (LAEF), LA reservoir strain (LASres), LA conduit strain (LAScond), LA contraction strain (LAScontr), LA peak systolic strain rates (LASRs), LA peak early diastolic strain rate (LASRe) and LA peak late diastolic strain rate (LASRa) using dedicated software on separate workstation (Cardiac Performance; TomTec Imaging, Unterschleissheim, Germany). Zero reference point was set at the onset of QRS wave.

Results
The index stroke was modest and non-disabling, with an NIHSS 3.2 ± 2.6. Baseline LA volumes and functions were in normal range (LAVi 27.4 ± 10.3 ml/m2; LASres 46.85 ± 19.6 %; LAScond 25.6 ± 15.4%; LAScontr 21.35 ± 12.15 %; LASRa -1.9 ± 0.77 s-1). The 6 month clinical follow-up examinations revealed no significant differences (all p values &gt;0.05) in atrial volumes and strain parameters. However, LASRa was significantly lower (-1.4 ± 0.82 s-1, p = 0.01). Closure device size (25mm vs 30mm) and smoking proved to be independent predictors of 25% decrease of LASRa (p = 0.06, p = 0.03, respectively). No new cerebral ischaemic events, aortic erosions, atrial fibrillation, significant residual shunts or device thrombosis and displacement were recorded during the follow-up.

Conclusion
PFO-associated strokes in young and middle-aged individuals are mainly non-disabling. Transcatheter interatrial closure was safe and effective in our study without promoting unfavourable anatomical atrial remodelling during short-term follow-up, however, it may affect active atrial contraction. Smoking and larger devices may decrease the rate of atrial deformation at short-term follow-up. Shorter PFO occluders are preferable in case of anatomical applicability.