PATIENTS AND METHODS

Between May 1998 and February 2000, 43 consecutive patients who were resident in the UK (median age 7 years, range 2.1–56.8 years) underwent closure of a haemodynamically significant secundum ASD. Patients were assessed by a standard echocardiographic protocol. All had full transthoracic examinations with a Sonos 2000 ultrasound system (Hewlett Packard, Palo Alto, California, USA) with a transducer appropriate to size and body weight (2.0–7.5 MHz). All patients had echocardiographic evidence of right ventricular dilatation.

Suitability for non-surgical closure was assessed according to the technique described by Reddy and colleagues.⁶ The diameter of the ASD was measured as were distances to the mitral valve, coronary sinus, pulmonary veins, superior vena cava, and inferior vena cava. Patients were not randomised to treatment groups. Those with suitable margins on transthoracic echocardiography were offered non-surgical closure.

The surgical group consisted of patients with deficient margins on two dimensional transthoracic echocardiography, patients in whom attempted non-surgical closure had failed, and patients with defects suitable for non-surgical closure but who opted for surgery. Subjects were prospectively followed up for up to one year.

Non-surgical closure

All procedures were performed under general anaesthesia. A detailed transoesophageal echocardiogram was obtained using the Sonos 2000 ultrasound system. No patients were found to have unsuitable margins on transoesophageal echocardiogram.

Cardiac catheterisation was carried out through the femoral vein. Pulmonary angiography was performed to exclude anomalous pulmonary venous return. Balloon sizing was determined using either a Meditech (Boston Scientific, Natick, Massachusetts, USA), Robicsek (BVM Medical, Earl Shelton, UK) or Fogarty (Baxter, Deerfield, Illinois, USA) balloon catheter. An Amplatzer ASD closure device of a size equal to the stretched defect diameter was deployed.

Surgical closure

Surgical closure was carried out using the standard technique under cardiopulmonary bypass by one of two cardiothoracic surgeons using direct suture or autologous pericardial patch.

Complications

Complications were prospectively recorded and divided into those affecting management and incidental findings. Patients were considered to have a pericardial effusion if there was a global collection greater than 3 mm on the echocardiogram. All patients with a postprocedural pericardial effusion had increased follow up surveillance until it resolved completely.

Non-invasive measurements

Non-invasive assessment consisted of end inspiratory chest radiography, standard 12 lead ECG, and transthoracic echocardiogram and was carried out before the procedure, on day 1, at six months, and at one year postprocedure. Patients after surgical closure of an ASD also had an echocardiogram on the day before discharge. All Amplatzer patients had a transoesophageal echocardiogram at three months after device insertion as part of our institutional protocol. Right ventricular dimensions were measured by transthoracic echocardiography in both groups of patients according to the technique of Ning and colleagues.⁷ Briefly, measurements were taken from the endocardium of the anterior wall of the right ventricle to the septum at the level of the tricuspid annulus in a four chamber apical view at end diastole. Three measurements were taken at the expiratory phase, with the least respiratory variation and the average taken.

Cost

An institutional accountant calculated cost per case based on information supplied on staff and disposables used, catheter laboratory or theatre time, anaesthetic costs, laboratory or clinical tests, and hospital stay. Patients were questioned about time taken off work or school using a confidential postal questionnaire sent after their discharge home.

Statistical analysis

Statistical analysis between the two groups was performed using the Mann-Whitney U test and Fisher's exact test. A probability value of p < 0.05 was considered significant.

RESULTS

Patient groups

Table 1 summarises the demographic characteristics of the groups, which differed demographically and anatomically. The Amplatzer group was older (median 9.7 years) than the surgical group (median 5.5 years) (p = 0.01) and had smaller defects (median 13 v 19 mm). These differences are explained by the selected nature of the groups, with the technical limitations of Amplatzer ASD occlusion favouring smaller defects in larger patients.

One patient in the Amplatzer group presented again four years after surgical ASD closure with right ventricular dilatation caused by patch dehiscence. The residual leaks were successfully occluded with two Amplatzer devices.

Procedural success and complications

There were no deaths in either group. Transcatheter deployment was successful in 24 of 27 (89%) patients. Three patients had successful Amplatzer ASD closures despite multiple defects that had not been recognised on precordial echocardiography. Device placement failed because a stable device position could not be achieved in two patients. In another an Amplatzer device was successfully deployed but embolised within the first 24 hours to the right ventricle. All three patients underwent successful surgical ASD closure (in two cases some months later) and were included in subsequent surgical analysis. Surgical closure was successful in all 19 patients.

Complications affecting management were observed in 4 of 19 (21%) surgical patients (one had pericardial pain requiring non-steroidal anti inflammatory drugs, one had global pericardial effusion requiring drainage (250 ml in the first 24 hours), one patient had anaemia requiring haematinics in addition to an incidental pericardial effusion, and one had further incidental pericardial effusion). However, only 10 of the 19 surgical patients (53%) were completely free from complications. The five remaining complications were minor (small pneumothoraces in three, junctional tachycardia in one, and a small pleural effusion on predischarge chest radiography) and did not require specific treatment.

Non-invasive follow up

Small leaks around the inferior margin of the device were seen in 3 of 22 patients on early postprocedural scans (on day 1 and transoesophageal echocardiogram at three months). These had all resolved by the six month echocardiogram.

Reduction in right ventricular end diastolic diameter (RVEDD) and cardiothoracic ratio (table 1) are expressed as the percentage change relative to the original preoperative measurements. Two patients in the Amplatzer group were pregnant during follow up and did not have chest radiography. The median reduction in RVEDD and cardiothoracic ratio at six months' follow up was similar for both groups.

The Amplatzer median RVEDD reduction at the six month follow up was 17.5% (range 0–45.8%) and the surgical median RVEDD reduction was 15.1% (range 0–56%) (p = 0.15) (fig 1). The Amplatzer group median cardiothoracic ratio reduction was 7.9% (range 0–28%) compared with a surgical median reduction of 7.5% (range 0–31%) (p = 0.56). The change in RVEDD in both groups was not predicted by ASD size or patient age.

There was a decrease in RVEDD at six months in all but five patients (three non-surgical, two surgical). In one of these patients there was a subsequent decrease in the RVEDD (21%) at the one year follow up with resolution of paradoxical septal motion. There was no change in the RVEDD in two other patients by 12 months and no 12 month follow up data are available on the remaining two.

Cost and patient stay

The median inpatient stay for the non-surgical group was one day (range 1–2 days) and for the surgical group six days (range 4–20 days) (p < 0.01). Patients returned to normal daily activities after a median two weeks (range 0.2–26 weeks) for the Amplatzer group and a median 5.5 weeks (range 4–9 weeks) (p < 0.01) for the surgical group.

The median cost to the institution per successful procedure was £5375 (range £5252–£8349) for the Amplatzer ASD group compared with £5412 (range £5112–£7512) for the surgical group (p = NS). The main cost differences were for equipment (median Amplatzer £2974 v surgical £408) and inpatient stay (median Amplatzer £300 v surgical £2410).

DISCUSSION

While it is established that both surgical and transcatheter closure of ASDs carry a low mortality^5,8–12 the two techniques have so far been compared only retrospectively.¹³ The aim of our study was to compare prospectively both techniques in detail. We considered effectiveness in terms of procedural success, complications, subsequent regression of right ventricular volume loading, cost, hospital stay, and time to return to normal activities.

Fewer patients undergoing Amplatzer ASD occlusion had a successful initial procedure than those undergoing surgery, in contrast to an earlier report quoting almost complete success rates for both procedures.¹³ The three technical failures in the Amplatzer group (subsequently requiring surgery) and the successful Amplatzer ASD occlusion after surgical dehiscence illustrate the complimentary role for both techniques in patients in whom the primary procedure fails. Most series quote cardiac complication rates of approximately 10–20% after surgical ASD closure.^13–15 In the comparative study by Berger and colleagues¹³ there was also no significant difference in the overall subsequent complication rate between surgical and Amplatzer ASD closure. We found a significant difference between the numbers of patients in each group who were affected by at least one complication (11% and 47% for non-surgical and surgical closure, respectively, p < 0.02). However, after excluding minor postsurgical complications that did not affect management (small pneumothoraces, junctional tachycardia), there was no significant difference between the two groups (11% and 21%, respectively, p = NS). Both techniques were similarly effective in reducing right ventricular dilatation at six months' follow up. There are few data on resolution of right ventricular volume loading after ASD closure.^7,16,17 Berger and colleagues¹⁷ describes normalisation within one week of closure, but other authors^7,16 report that ventricular dilatation can persist for up to five years. In our study, we saw almost no change in tricuspid annular diameter in early postprocedural scans (< 6 months). Although there was some resolution of right ventricular dilatation by six months, all of the patients were still outside the age corrected normal range for RVEDD.^18,19 Further regression was seen in some of the patients with follow up data at one year but still none of these subjects had normal RVEDD.

Cost analysis shows that the two procedures have similar resource implications in this National Health Service costing framework. Comparison of median cost does not reflect the cost burden of the additional Amplatzer devices used in unsuccessful closure attempts and the two devices used in a single patient. The mean Amplatzer ASD closure cost is £363 higher than the cost of surgical closure. The main areas of difference between the groups were the high cost of the Amplatzer device and longer hospital stay in the surgical patients. Similar differences in cost break down were reported by Prieto and colleagues²⁰ and Gray and associates²¹ in comparisons of surgical with non-surgical persistent ductus arteriosus closure.

Median time to return to normal activities was significantly shorter in the Amplatzer group and much shorter than the 3–14 days reported by Berger and colleagues.¹³ Interestingly, the range of time taken off work or school was wide in both groups, which was often contrary to the advice given to the patients on the timing of return to normal activities.

Conclusions

Amplatzer ASD closure has a lower chance of success with a single procedure than surgery. Overall there were more complications in the surgical group but the majority of these were minor and did not require any change in management. Resolution of right ventricular dilatation is similar after both types of treatment. Hospital stay and time taken to return to normal activities was significantly shorter for the Amplatzer group patients, but median cost was similar for both groups.