Safety, Feasibility, and Long-Term Results of Percutaneous Closure of Atrial Septal Defects Using the Amplatzer Septal Occluder Without Periprocedural Echocardiography

Abstract: Objectives. We sought to assess the safety and efficacy of percutaneous closure of atrial septal defects (ASDs) under fluoroscopic guidance only, without periprocedural echocardiographic guidance. Background. Percutaneous closure of ASDs is usually performed using simultaneous fluoroscopic and transthoracic, transesophageal (TEE), or intracardiac echocardiographic (ICE) guidance. However, TEE requires deep sedation or general anesthesia, which considerably lengthens the procedure. TEE and ICE increase costs. Methods. Between 1997 and 2008, a total of 217 consecutive patients (age, 38 ± 22 years; 155 females and 62 males), of whom 44 were children ≤16 years, underwent percutaneous ASD closure with an Amplatzer ASD occluder (AASDO). TEE guidance and general anesthesia were restricted to the children, while devices were implanted under fluoroscopic guidance only in the adults. For comparison of technical safety and feasibility of the procedure without echocardiographic guidance, the children served as a control group. Results. The implantation procedure was successful in all but 3 patients (1 child and 2 adults; 1.4%). Mean device size was 23 ± 8 mm (range, 4-40 mm). There was 1 postprocedural complication (0.5%; transient perimyocarditis in an adult patient). At last echocardiographic follow-up, 13 ± 23 months after the procedure, 90% of patients had no residual shunt, whereas a minimal, moderate, or large shunt persisted in 7%, 1%, and 2%, respectively. Four adult patients (2%) underwent implantation of a second device for a residual shunt. During a mean follow-up period of 3 ± 2 years, 2 deaths and 1 ischemic stroke occurred. Conclusion. According to these results, percutaneous ASD closure using the AASDO without periprocedural echocardiographic guidance seems safe and feasible. 

J INVASIVE CARDIOL 2015;27(3):157-162

Key words: atrial septal defect, percutaneous closure

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An atrial septal defect (ASD) prevails in about 4 of 100,000 newborns, with a 3:1 female preponderance. ASDs account for approximately one-third of congenital heart disease detected in adults, and 75% of them are ostium secundum defects (ASD II) located in the region of the fossa ovalis.¹ Spontaneous closure is unlikely in adults, and a relevant proportion of patients eventually develop symptoms due to atrial arrhythmias, cardiac failure, pulmonary hypertension, or paradoxical embolism. This results in a shortened overall life expectancy.^2,3 Surgical ASD closure, first performed in 1953, has been shown to significantly reduce mortality as compared to medical treatment in symptomatic patients.^4-6 Since the first percutaneous intervention reported by King and Mills in 1976,⁷ percutaneous closure has become the technique of choice in suitable pediatric and adult patients with ASD II.

According to a recent meta-analysis of non-randomized studies of ASD II closure in 3082 patients, of whom 1270 were treated surgically and 1812 percutaneously, patients treated surgically had a 5.4-fold and 3.8-fold higher risk of total and major complications, respectively, and a 2.5-times longer hospital stay.⁸ However, these data have yet to be confirmed in a randomized trial. In a retrospective population-based cohort study comparing 383 surgical and 335 percutaneous cases,⁹ percutaneous ASD II closure was associated with a higher long-term reintervention rate, but long-term mortality was not inferior to surgery. Considering the excellent safety results, the acceptable cost¹⁰ of the percutaneous technique, and the expected reduction in morbidity and mortality, it has been suggested that the intervention should be performed early after diagnosis at any age (body size permitting) and irrespective of symptoms.¹¹

Most ASD II cases that are 35 mm or smaller by echocardiography can be closed percutaneously. Percutaneous ASD II closure is usually performed with the Amplatzer ASD occluder (AASDO; St. Jude Medical), using simultaneous fluoroscopic and transthoracic (TTE), transesophageal (TEE), or intracardiac echocardiographic (ICE) guidance. However, TEE requires deep sedation (with a risk of bronchoaspiration due to the supine position) or general anesthesia. Despite almost comparable global charges,¹² ICE catheters are still not reimbursed by health insurance agencies in many countries, limiting their use. Additional venous cannulation doubles the risk of vascular access complications. Besides, both considerably lengthen the procedure. While some interventional cardiologists have adopted closing a patent foramen ovale (PFO) without periprocedural TEE or ICE,^13-15 this is hardly the case for ASD closure. Particular concerns include the risk of device embolization or failure to detect multiple defects. 

We investigated the safety, feasibility, and long-term efficacy of percutaneous ASD II closure under fluoroscopic guidance only, without peri-interventional echocardiography, and compared the results to the conventional procedure with general anesthesia and TEE guidance. The children (patients ≤16 years old) served as the control group.

Methods

Patients. Between 1997 and 2008, a total of 217 consecutive patients underwent percutaneous ASD II closure with AASDOs at our institution. Patients with prior implantation of other devices, prior incomplete surgical ASD closure, or complex congenital heart disease were excluded from the analysis. In children, general anesthesia with intubation and both TEE and fluoroscopic guidance were used. In adults, devices were implanted under local anesthesia and fluoroscopic guidance only. The procedure and follow-up evaluation were approved by the local ethics committee and patients gave written informed consent.

Echocardiography. Preprocedural TEE was routinely performed in all adult patients screened for percutaneous ASD closure in order to examine ASD morphology and to exclude additional abnormalities, such as an anomalous pulmonary venous drainage. ASD II was diagnosed in the presence of a tissue defect within or adjacent to the fossa ovalis associated with left-to-right shunt detected on TTE or TEE. In children, the preoperative evaluations consisted of repeated TTE studies to assess volume overload and enlargement of the right heart in order to determine the appropriate time for closure. 

Amplatzer ASD occluder. The AASDO is a self-expandable, nitinol, wire-mesh double disc with a broad connecting neck between the discs and polyethylene terephthalate inlays. The device comes in sizes of 4-40 mm (diameter of the connecting neck, for disc add up to 14 mm depending on device size), and is deployed through a venous sheath with diameters up to 12 Fr (4 mm) for the largest 40 mm AASDO (Figure 1). The Amplatzer cribriform occluder is designed to close multifenestrated (“Swiss cheese”) ASDs. It has a narrow waist that allows placement through one of the central holes of the interatrial septum, with the discs also covering the surrounding holes. For medium-to-large centrally located defects, the AASDO has the best procedural results reported so far, with the lowest rates of device embolization, residual shunt,^16,17 and thrombus formation^18,19 among available devices. It is generally the device of choice for closing ASDs, particularly those with a deficient anterior rim.²⁰ In recent reports, comparable device performances were described for the structurally closely related Occlutech Figulla ASD occluder (Occlutech).^21,22 

Percutaneous ASD closure. Percutaneous ASD II closure was performed from the right femoral vein. In males >40 years old and females >50 years old, or in patients with particular risk factors or signs or symptoms of coronary artery disease, a coronary angiogram was performed during the same procedure before ASD closure. Shunt volume was determined in selected patients using the Fick principle by stepwise oxymetric measurements in the superior vena cava, inferior vena cava, right ventricle, and pulmonary artery.

Balloon sizing of the defect was performed in all cases in order to choose the appropriate device size. An AASDO was used in all cases. Device size was selected depending on the ASD diameter as assessed during balloon sizing of the defect (Figure 2). In cases where the balloon was firmly stabilized in the ASD on a regular 0.035˝ guidewire, the device was selected about 30% larger than the ASD diameter as assessed by determination of the diameter of the waist of the sizing balloon. In other cases, oversizing was 50% or more.

After confirming a secure position by a push-and-pull maneuver (wiggling), a right atrial angiography was performed to assess correct positioning in a projection showing the device in strict profile with no overlap of the discs. Contrast medium was injected through the delivery sheath. The contrast was followed through to the left atrium (levophase) depicting the correct position of the left disc during the ensuing left atriogram. The device was finally released from the delivery system. 

Patients were allowed to resume full physical activity a few hours after the procedure, which was often performed on an outpatient basis in adults. They were treated with acetylsalicylic acid 100 mg once daily for 3-6 months and most patients also took clopidogrel 75 mg once daily for 1-3 months for antithrombotic protection until full device coverage by endocardium. Contrast TTE was performed in all patients (children and adults) before discharge in order to confirm unchanged device position. 

Follow-up evaluation. All adult patients were scheduled for a 6-month contrast TEE, while contrast TTEs were performed in children at 3 months and 1 year. In case of a significant residual shunt, implantation of a second device or surgical closure was recommended. Patients were actively followed for major adverse events using questionnaires, personal interviews, or telephone contacts. Questions addressed survival, signs and symptoms of heart failure, arrhythmias, cerebrovascular or peripheral embolic events, and device- or medication-related problems. Vital status was ascertained from hospital records and municipal civil registries. For suspected events, relevant medical records and documentation of imaging procedures were collected from hospitals and referring physicians.

Statistical analysis. Intention-to-treat analysis was performed. Continuous variables are expressed as mean ± one standard deviation, and were compared by a two-sided, unpaired t-test. Categorical variables are reported as counts and percentages, and were compared by c² analysis. Binary logistic regression was used to identify independent factors predicting occurrence of new-onset atrial arrhythmia and residual shunt at 6 months. Statistical significance was assumed with a P<.05. All data were analyzed with the use of SPSS software, version 17.0 (SPSS, Inc).

Results

Baseline characteristics. Demographic data are summarized in Table 1. The ASD II was found fortuitously in 90 patients (41%), following a stroke or a transient ischemic attack (TIA) in 33 patients (15%), because of dyspnea in 51 patients (23%), arrhythmia in 23 patients (11%), chest pain in 10 patients (5%), dizziness with or without syncope in 8 patients (4%), and a myocardial infarction presumably due to paradoxical embolism, or a decompression illness in 1 patient (0.5%). Signs of right heart overload (defined as right ventricular dilatation at echocardiography or electrocardiographic signs of right heart overload) were more often found in children than in adults (73% vs 45%; P=.01).

In-hospital outcomes. Procedural outcomes are shown in Table 2. The adult patients had larger ASDs and higher pulmonary pressure values. The implantation procedure (release of a device) was successful in all but 3 patients (1 child and 2 adults; 1.4%). The 3-year old child underwent surgical closure 1 day after the intervention because of large residual shunt due to poor device position. In the 2 adult patients, stable positioning of the largest available device (40 mm) could not be achieved and the procedure was aborted without releasing the device. These ASDs were surgically closed a few weeks later.

In the 173 adults, the mean diameter of the defect was 15 ± 7 mm (range, 2-36 mm) at TEE before the intervention, and the stretched balloon diameter was 20 ± 8 mm (range, 3-38 mm). Mean device size (diameter of the neck between disks) was 23 ± 9 mm (range, 7-40 mm). Total procedural time, including percutaneous ASD closure in all cases, incidental coronary angiography in 106 patients (61%), and percutaneous coronary intervention in 13 patients (8%), was 44 ± 22 minutes (median, 39 minutes). Fluoroscopy time was 10 ± 7 minutes (median, 8 minutes). There was 1 procedural complication without long-term sequelae (0.6%), ie, transient perimyocarditis, possibly related to the device.

In the 44 children, the mean diameter of the defect was 12 ± 3 mm (range, 7-26 mm) at TEE, and the stretched balloon diameter was 17 ± 5 mm (range, 7-40 mm). Mean device size was 20 ± 6 mm (range, 12-40 mm). There were no procedural complications. Total procedure time was 66 ± 21 minutes (median, 63 minutes) and fluoroscopy time was 12 ± 16 minutes (median, 9 minutes). Contrast TTE within 24 hours of percutaneous ASD closure detected a residual shunt in 30% of adults and 9% of children (P=.01). 

Follow-up. No thrombi were detected on the device and there were no other device-related complications. Patients with larger ASDs, defined as a device size >25 mm (n = 83), needed more frequent surgical closure after transcatheter intervention as compared to patients with smaller ASDs (<25 mm; n = 134; 5% vs 0%; P=.01). Moreover, increasing diameter of the defect was predictive of the persistence of a residual shunt at 6 months (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.0-2.0; P=.048).

Adults. Follow-up with contrast TEE at 6 months was completed in 80% of the patients and with TTE in an additional 16%. Complete ASD closure as assessed by contrast TEE or TTE was achieved in 89% of patients, whereas a minimal, moderate, or large residual shunt persisted in 9%, 1%, or 1% of patients, respectively. One patient with a large residual shunt was referred for surgical closure 6 months after transcatheter intervention. 

Four patients (2%) underwent a second percutaneous intervention due to the persistence of a residual shunt through the former ASD. In 1 patient with Swiss cheese ASD,²³ complete closure was achieved after three interventions with implantation of 4 AASDOs (8 mm, 14 mm, and 2 x 20 mm). In 1 patient, a residual shunt due to partial device dislocation was successfully closed using 2 Amplatzer vascular plugs implanted during two procedures performed 2 and 3 years after the initial intervention. In the 2 remaining patients, closure was achieved using a second AASDO (20 and 22 mm, respectively) without complication. Thus, complete percutaneous closure was finally achieved in all 4 of these patients. No significant differences in procedural outcome were found between older patients (≥60 years old; n = 34) and patients <60 years old.

Children. Contrast TTE at 1 year (obtained in 80% of patients) showed complete closure in 97%. In 1 patient (3%), a large residual shunt persisted at the lower border of the device, with sustained right heart enlargement. Surgical closure was performed 1 year after device implantation.

Late clinical outcome. Three patients (1%) were lost to follow-up. During a mean follow-up period of 2.8 ± 2.3 years (median, 2.2 years; range, 0.5-14.7 years), there were 2 deaths (73-year-old female, 19 months after device implantation, cause unknown; 56-year-old male, 9 years after device implantation, terminal hepatic cirrhosis). No autopsy has been performed in the 73-year-old woman, so late atrial wall erosion cannot be excluded as a cause of death. A 27-year-old female suffered an ischemic stroke due to acute occlusion of the basilar artery 4 years after ASD closure. Selective intraarterial lysis was successfully performed and the patient had no long-term sequelae. Contrast TEE 8 days after the event showed no thrombus on the device, and confirmed correct position without residual shunt. The etiology of the ischemic stroke remained unclear. No transient ischemic attack, peripheral embolic event, or decompression illness was reported. Dyspnea stratified according to New York Heart Association (NYHA) classification improved significantly in adult patients (NYHA 2.5 ± 0.5 to NYHA 1.3 ± 0.5; P<.001).

Atrial arrhythmia. New-onset atrial arrhythmias occurred in 19 adults (9%), but in no children. Thirteen patients (6%) reported non-sustained palpitations and 6 patients (3%) were diagnosed with new-onset atrial fibrillation. Treatment with antiarrhythmic drugs was initiated in 3 cases and 1 patient underwent successful electric cardioversion. 

Adults had significantly more documented postinterventional arrhythmias than children (11% vs 0%; P=.02). Smoking (OR, 3.6; 95% CI, 1.1-11.9; P=.03), presence of a residual shunt at day 1 (OR, 3.8; 95% CI, 1.2-12.0; P=.02), and larger ASDs (OR, 1.2; 95% CI, 1.0-1.3; P=.06) were independent predictors of the occurrence of atrial arrhythmia. Patients with right heart enlargement at echocardiography more often experienced episodes of atrial fibrillation (5% vs 0%; P=.01).

Discussion

This study is the largest series of consecutive patients treated at a single center reported to date to investigate the safety, feasibility, and long-term clinical efficacy of percutaneous ASD closure with the AASDO under fluoroscopic guidance only without periprocedural TTE, TEE, or ICE. On the basis of these data, percutaneous ASD closure using a simplified technique seems to be feasible in comparison to the conventional intervention with additional imaging as performed in the children comparator group.

The procedure itself was about 20 minutes shorter in the adult patients (including coronary angiogram in 61% of patients and PCI in 8% of patients, and discounting anesthesia preparation and wake-up phase in children). As an alternative, other groups suggested the use of ICE,^24,25 which is more comfortable for the patient, but increases the invasive risk due to the necessity of a second femoral venous cannulation.

The procedural outcomes are summarized in Table 2. Adult patients had more residual shunts at discharge (30% vs 9% in the children group). However, the adult patients had larger baseline shunts requiring larger devices and some of them presented with complex defects, eg, Swiss cheese ASD. Children with similar complex anatomical characteristics were more likely to be primarily referred for surgery. However, besides these important anatomical considerations, the present non-randomized study is not able to determine whether this difference was due to the lack of echocardiographic guidance. The discrepancy abates but remains statistically significant after endothelialization of the devices. At 6 months, complete occlusion was achieved in 88% of the adults vs 97% of the children (P=.01). It is noteworthy that contrast TEE was generally used for follow-up in adults, while children underwent contrast TTE only. TTE has a lower sensitivity for residual shunts than TEE. Hence, the residual shunt rate in the children’s group may have been underestimated despite their generally good TTE windows. Importantly, 66% of the residual shunts in the adults were minimal, without any clinical significance, and did not require further intervention. The rate of repeat procedures (second percutaneous intervention or surgery) was similar in both groups (3% in adults vs 5% in children). As already established for PFO closure devices,¹³ the analysis of the data confirmed the plausible association between larger defects and the presence of residual shunts during follow-up. The intervention was as feasible and safe in older adults (≥60 years old) as in younger adults.

Atrial free-wall erosion, a rare but dramatic complication allegedly associated with device oversizing, was not observed in this study during the mean follow-up period of almost 3 years. However, very late erosions occurring up to 8 years after implantation have been described.²⁶

Another important concern is the incidence of atrial arrhythmias, in particular new-onset atrial fibrillation occurring after device implantation. The incidence of symptomatic new-onset atrial arrhythmias in our study was 9% (3% atrial fibrillation), which is comparable to recent reports specifically investigating this issue after ASD closure with AASDOs.^27,28 We identified smoking, the presence of a residual shunt at day 1, and larger ASD II size as independent predictors of atrial arrhythmias. Furthermore, patients with right heart enlargement at echocardiography more often experienced episodes of atrial fibrillation.

Conclusion

In this sizable series of percutaneous ASD II closures without TTE, TEE, or ICE guidance in adults, device success was close to 100%, and the periprocedural complication rate was below 1%. The complication rates and incidence of repeat procedures were statistically similar among adults undergoing ASD II closure under fluoroscopic guidance only as compared to children in whom general anesthesia with intubation and TEE were invariably utilized. However, only a randomized study would be able to confirm this statement. Of note, all adult patients underwent routine TEE for initial diagnosis of ASD and assessment of suitability of percutaneous closure. Our data suggest that a simplified procedure of ASD closure without use of TEE is a valuable alternative to the standard procedure in experienced centers.

Study limitations. Limitations include the retrospective non-randomized design of the study and the absence of a true control group, since children undergoing ASD closure are different from adults. Moreover, patients did not undergo systematic screening with Holter monitoring. As a consequence, asymptomatic patients with paroxysmal atrial fibrillation before or after the intervention may have been missed. 

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From the Department of Cardiology, Bern University Hospital, Bern, Switzerland.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Windecker reports honoraria from AstraZeneca, Eli Lilly, Abbott, Biosensors, Boston Scientific, and Bayer; research grants to the institution from St. Jude, Biotronik, Medicines Company, Abbott, Medtronic, Boston Scientific, and Edwards Lifesciences. Dr Meier reports research grants and speaker’s fees from St. Jude Medical, Astra Zeneca, Bayer, Daiichi Sankyo, Eli Lilly, Medtronic, Boston Scientific, and Pfizer Corporation. The remaining authors disclose no conflicts of interest regarding the content herein.

Manuscript submitted April 7, 2014, provisional acceptance given April 25, 2014, final version accepted June 30, 2014.

Address for correspondence: Bernhard Meier, MD, FACC, FESC, Professor and Chairman of Cardiology, Cardiology, Bern University Hospital, 3010 Bern, Switzerland. Email: bernhard.meier@insel.ch