Traditional single patch versus the “Australian” technique for repair of complete atrioventricular canal defects

Modified Single-Patch versus Two-Patch Repair for Atrioventricular Septal Defect: A Systematic Review and Meta-Analysis

BACKGROUND

We performed a meta-analysis of studies to determine whether the modified single-patch technique offers benefits when compared to the two-patch repair. The postoperative outcomes examined in this study were cardiopulmonary bypass time, cross-clamp time, duration of mechanical ventilation, intensive care unit length of stay, total hospital length of stay, need for reoperation, need for reoperation for left ventricular outflow tract obstruction or left atrioventricular valve regurgitation, need for pacemaker implantation, and mortality during follow-up.

METHODS

A review was conducted to identify studies comparing a modified single-patch repair versus two-patch repair. A fixed-effects model was utilized for end points with low heterogeneity and a random-effects model for end points with significant heterogeneity. Meta-regression was also performed to determine the influence of other factors on the variables of interest.

RESULTS

A total of 964 unique manuscripts were screened, with 10 being included in the final analyses. There were a total of 724 patients, with 353 (49%) having undergone repair utilizing a modified single-patch repair. Mean age at repair for modified single-patch repair and two-patch repair was 8.81 and 9.03 months, respectively. Significant differences were noted in cardiopulmonary bypass time and cross-clamp time with mean difference of -28.53 and -22.69 minutes, respectively. In comparison to the two-patch repair, both times were decreased in modified single-patch repair. No significant difference was noted in any other variables.

CONCLUSIONS

Modified single-patch repair for atrioventricular septal defects requires less cardiopulmonary bypass and cross-clamp time but does not significantly impact the examined postoperative outcomes.

A review of the Nunn modified single patch technique for atrioventricular septal defect repair

Atrioventricular septal defect (AVSD) is a common congenital cardiac surgical problem. Over the years, younger and smaller infants are having operations for this condition before irreversible cardio pulmonary changes occur. Traditionally a single or two patch techniques have been used to repair this defect. However, in the past two decades an innovative method of modified single patch technique popularized by Dr. Graham Nunn has gained worldwide popularity. This review discusses the origin, surgical principles, technique and outcomes of this method, popularly known as Nunn or Australian technique. Research comparing the modified single patch technique to classic single and double patch techniques has shown good preservation of atrioventricular valve function, no residual ventricular septal defect (VSDs), low incidence of left ventricular outflow obstruction, preserved conduction, easy reproducibility, and improved perioperative and long-term mortality.

Modified Single-Patch Technique Versus Two-Patch Technique for the Repair of Complete Atrioventricular Septal Defect: A Meta-Analysis

Technical selection for surgical repair of complete atrioventricular septal defect (CAVSD) still remains controversial. This meta-analysis aimed to compare the modified single-patch (MP) technique with the two-patch (TP) technique for patients with CAVSD. Relevant studies comparing the MP technique with the TP technique were identified through a literature search using MEDLINE, EMBASE, Google Scholar, Cochrane Library, and the China National Knowledge Infrastructure databases. The variables were ventricular septal defect (VSD) size, cardiopulmonary bypass (CBP) time, aortic cross-clamp (ACC) time, intensive care unit stay, hospital stay, and other outcomes involving mortality, left ventricular outflow tract obstruction, atrioventricular valve regurgitation, residual septal shunt, atrioventricular block, and reoperation. A random-effect/fixed-effect model was used to summarize the estimates of mean difference/odds ratio with 95% confidence interval. Subgroup analysis stratified by region was performed. Fifteen publications involving 1034 patients were included. This meta-analysis demonstrated that (1) VSD size in the MP group was significantly smaller; (2) CBP time, ACC time, and hospital stay in the MP group experienced improvement; (3) Other postoperative outcomes showed no significant differences between two groups; and (4) The trends in China and other countries were close. The MP and TP techniques had comparable outcomes; however, the MP technique was performed with significantly shorter CBP and ACC times in patients with smaller VSDs. Given this limitation of data, the results of comparison of the two techniques in patients with larger VSDs remain unknown. Further studies are needed.

Surgical repair of complete atrioventricular defect (Nunn technique)

Two procedures have been traditionally used for the surgical repair of complete atrioventricular canal. The single-patch technique includes the division of valve leaflets, and the use of one patch to close the ventricular and the atrial septal defects, whereas the double-patch technique uses two separate patches, without the division of the bridging leaflets. Between 1997 and 2007, another technique emerged, the modified single-patch technique, or the 'Australian' technique, whereby the ventricular septal defect (VSD) is closed by the direct apposition of the bridging leaflets against the crest of the defect. Because of the absence of the ventricular septal patch, concerns have been raised about the possible left ventricular outflow tract obstruction (LVOTO), or atrioventricular valve (AVV) distortion, especially in case of a deep VSD, or if the defect extends superiorly. The results of the modified single-patch technique in terms of mortality, immediate and long-term AVV function and LVOTO have been similar to the standard techniques in most reports. This article will describe in detail the operative technique and review the relevant literature.

Surgical management of complete atrioventricular septal defect: associations with surgical technique, age, and trisomy 21

OBJECTIVES

We sought to evaluate the contemporary results after repair of a complete atrioventricular septal defect and to determine the factors associated with suboptimal outcomes.

METHODS

The demographic, procedural, and outcome data were obtained within 1 and 6 months after repair of a complete atrioventricular septal defect in 120 children in a multicenter observational study from June 2004 to 2006.

RESULTS

The median age at surgery was 3.7 months (range, 9 days to 1.1 years). The type of surgical repair was a single patch (18%), double patch (72%), and a single atrial septal defect patch with primary ventricular septal defect closure (10%). The incidence of residual septal defects and the degree of left atrioventricular valve regurgitation (LAVVR) did not differ by repair type. The median interval of intensive care stay were 4 days, ventilation use 2 days, and total hospitalization 8 days. All were independent of the presence of trisomy 21 (80% of the cohort). The in-hospital mortality rate was 2.5% (3/120). The overall 6-month mortality rate was 4% (5/120). The presence of associated anomalies and younger age at surgery were independently associated with a longer hospital stay. The age at repair was not associated with residual ventricular septal defect or moderate or greater LAVVR at 6 months. Moderate or greater LAVVR occurred in 22% at 6 months, and the strongest predictor for this was moderate or greater LAVVR at 1 month (odds ratio, 6.9; 95% confidence interval, 2.2-21.7; P < .001).

CONCLUSIONS

The outcomes after repair of complete atrioventricular septal defect did not differ by repair type or the presence of trisomy 21. An earlier age at surgery was associated with increased resource use but had no association with the incidence of residual ventricular septal defect or significant LAVVR.