Mid-term follow-up of interventional closure of atrial septal defect using Solysafe™ Septal Occluder — Impact of standardized fluoroscopy for complication detection

Abstract

Interventional closure of secundum type atrial septal defects (ASD II) and patent foramen ovale (PFO) has been developed as standard of care for the majority of pediatric patients, with different types of occlusion devices available [1]. The SolysafeTM Septal Occluder (Swissimplant AG, Solothurn, Switzerland) has been developed for interventional closure of ASD II and PFO and has been evaluated in clinical studies for adult [2,3] and pediatric patients [4]. In August 2010, due to a voluntary recall of SolysafeTM Septal Occluder (SSO) by Swissimplant caused by sporadic clinical reports about irregularities of the device in follow-up controls the use of SSO stopped immediately [www.swissimplant.com]. Therefore, we analyzed the incidence of irregularities associated with SSO during mid-term follow-up in our institution by analyzing patients after successful implantation of SSO. Criteria for ASD closure using SSO were size of balloon stretched ASD diameter between 5 and 25 mm, relevant left to right shunt, determined by Fick with Qp: Qs≥1.5:1, and/or echocardiographic signs of right atrial or right ventricular volume overload. The procedure was performed as recently published [2,4]. Post-procedural follow-up included clinical assessment, transthoracic echocardiography, electrocardiography (ECG) including Holter. Data are presented as mean±standard deviation, range, and percentages. We focussed our analysis on the results of standardized fluoroscopic loops recorded after recall of the device in August 2010. We performed four radiographic views (straight anterior posterior, straight lateral, lateral and en-face profile of the device) as recommended by the company. SSO were successfully implanted in 51 pediatric patients (male: female=24:27) at an age (mean±SD) of 8.0±4.6 years (range 1.6– 17.8 years) and a bodyweight of 29.1±18.1 kg (9.5–86) between April 2007 and June 2010. ASD II presented as solitary defects (n=39), two defects (n=11), or multiple defects (n=1) with a significant left to right shunt: Qp:Qs=1.7±0.7 (1.0–4.0), native and balloon stretched size of 10.0±3.9 mm (5–20) and 12.5±4.7 mm (6.5–23), respectively, determined by transesophageal echocardiography. During midterm follow-up of 2.1±0.9 years (0.5–3.7), patients were clinically asymptomatic and echocardiography revealed a complete closure rate of 94.9% (48 of 51 patients). All patients were clinically asymptomatic, routine ECG and Holter ECG did not show any significant findings. Transthoracic echocardiography did not reveal signs of wire fractures. But, fluoroscopy showed new complications in two patients (3.9%), not determined by transthoracic echocardiography before. The cases are presented in the section below. In a 7.9-year-old boy a 25 mm SSO was implanted. Left-to-right shunt (Qp:Qs) was 1.6 to 1. Two defects with a native size of 11 mm and 3 mmwere found in trans-thoracic echocardiography. The balloon stretched diameter of the larger defect was 16 mm and completely occluded both defects during balloon sizing. The post-procedural course was uneventful, transthoracic echocardiography did not reveal any residual shunt. But, two years after implantation, fluoroscopy revealed a fixed singular fracture of one wire loop not leaving the perimeter of the occluder occurred (Fig. 1). Without any further therapeutic consequences, the patient is still asymptomatic after six months follow-up including normal Holter electrocardiography. In a second boy (age 5.0 years, body weight 19 kg) 30 mm SSOwas implanted in a solitary central defect with native and stretched diameter of 20 and 23 mm, respectively. During follow-up a small residual shunt remained. Two years later, fluoroscopy visualized multiple fractures of wire loops on both sides of the device, with embolization of wire parts to the left and right pulmonary lower lobe artery (Fig. 2). Due to fractured wire ends striking out of the septum on both sides causing injury of the anterior mitral valve leaflet, cardiac surgery was performed with complete explantation of the SSO including successful mitral valve repair and patch closure of the ASD (Fig. 3). Postoperative course and further follow-up was uneventful (N6 months). In the past, fractured legs of ClamshellTM devices have been frequently seen, but did not lead to significant complications over a 12 year follow-up [1]. Similarly, fractures in the CardioSEALTM and STARFlexTM devices have been described, but the incidence and the