Anatomically sound, simplified approach to repair of "complete" atrioventricular septal defect

Overview: history, anatomy, timing, and results of complete atrioventricular canal

The past 50 years have been marked by major advances in the care of children with complete atrioventricular canal defects. There have been important contributions from surgeons, cardiologists, and pathologists to provide us with our current understanding of the anatomy of atrioventricular canal defects and excellent surgical outcomes. In this monograph we will discuss the surgical contributions of Lillehei, Kirklin, McGoon, Maloney, Trusler, Wilcox, and Nunn. The improvements in outcomes achieved by these surgeons were made possible by the pathology and anatomy clarifications provided by Lev, Rastelli, and Anderson.

The double patch repair for complete atrioventricularis communis

This article is a review of our experience with the two-patch repair of complete atrioventricularis communis. From October 1988 through December 2005, 222 infants and children underwent surgery. There were six early (2.7%) and six late (2.7%) deaths. Reoperation was required in 22 patients (10%) for residual or recurrent mitral regurgitation or stenosis, subaortic stenosis, repair of a ventricular septal defect with or without pulmonary stenosis, placement of a right heart valved conduit, and/or placement of a permanent cardiac pacemaker. All patients survived second operations and no child required early or late mitral valve replacement. The two-patch repair is a reliable surgical technique resulting in low mortality and a low need for reoperation.

Echo-morphological correlates in patients with atrioventricular septal defect and common atrioventricular junction

It is now well recognized that patients fulfilling the diagnostic criterions for the group of hearts usually described as atrioventricular canal malformations, or atrioventricular septal defects, can present with shunting at atrial level, at both atrial and ventricular levels, and on occasion, with shunting only at ventricular level.1,2It is also well recognized that, in most instances, the patients with shunting exclusively at atrial level have separate atrioventricular valvar orifices for the right and left ventricles, this arrangement often described as the “ostium primum” variant of atrial septal defect.3Morphological and echocardiographic studies, however, have shown that, in this variant presumed to represent deficient atrial septation, it is the atrioventricular septal structures, rather than the atrial septum, which are deficient, the phenotypic feature being the presence of a common atrioventricular junction.4,5In this review, we will show how, using modern day echocardiographic techniques, particularly the newly developed potential for three-dimensional display, it is an easy matter to identify the presence or absence of the common atrioventricular junction, and then to demonstrate the various relationships between the valvar leaflets, the septal structures, and the common junction itself which determine the options for clinical presentation within the group.

Surgical repair of atrioventricular septal defect with common atrioventricular valve in early infancy

The repair of atrioventricular septal defect with a common atrioventricular valve is reconstructive surgery at its best, and hence one of the favourite operations performed by paediatric cardiac surgeons. In the past, the post-operative course from such patients was dominated by the occurrence of pulmonary hypertension crises, which were responsible for significant morbidity and mortality. Nowadays, repair is generally undertaken early in infancy, and this approach has mitigated the problems emanating from pulmonary hypertension. Coupled with a better understanding of the anatomy, and adaptation of the surgical techniques, repair can now be achieved safely at around 2 to 4 months of life, without increasing the risk of postoperative regurgitation across the reconstructed left atrioventricular valve. In this review, we discuss the surgical techniques required for, and clinical results of, such early repair.

No patch technique for complete atrioventricular canal repair

We describe our initial experience with a new technique, consisting in direct closure of the ventricular septal defect component of the AV canal, by directly attaching the common bridging leaflets to the crest of the ventricular septum with interrupted sutures. After closure of the cleft, the ostium primum defect was closed with a running suture suturing the border of the septum primum to the newly created AV valve annulus. Three patients were operated upon. There was no mortality. Mean ischemic time was 39 min and mean pump time 77 min. All patients remained in sinus rhythm. At follow-up only trivial or mild mitral regurgitation was observed. This new technique permits the repair of complete AV canal without the need for any patch. It is fast, simple and reproducible.

Complete atrioventricular canal

Complete atrioventricular canal (CAVC), also referred to as complete atrioventricular septal defect, is characterised by an ostium primum atrial septal defect, a common atrioventricular valve and a variable deficiency of the ventricular septum inflow. CAVC is an uncommon congenital heart disease, accounting for about 3% of cardiac malformations. Atrioventricular canal occurs in two out of every 10,000 live births. Both sexes are equally affected and a striking association with Down syndrome was found. Depending on the morphology of the superior leaflet of the common atrioventricular valve, 3 types of CAVC have been delineated (type A, B and C, according to Rastelli's classification). CAVC results in a significant interatrial and interventricular systemic-to-pulmonary shunt, thus inducing right ventricular pressure and volume overload and pulmonary hypertension. It becomes symptomatic in infancy due to congestive heart failure and failure to thrive. Diagnosis of CAVC might be suspected from electrocardiographic and chest X-ray findings. Echocardiography confirms it and gives anatomical details. Over time, pulmonary hypertension becomes irreversible, thus precluding the surgical therapy. This is the reason why cardiac catheterisation is not mandatory in infants (less than 6 months) but is indicated in older patients if irreversible pulmonary hypertension is suspected. Medical treatment (digitalis, diuretics, vasodilators) plays a role only as a bridge toward surgery, usually performed between the 3rd and 6th month of life.

Predictive Value of Intraoperative Transesophageal Echocardiography in Complete Atrioventricular Septal Defect

BACKGROUND

Intraoperative transesophageal echocardiography and follow-up transthoracic echocardiography have been useful in assessing cardiac function in complete atrioventricular septal defects. However, it has been suggested that a discrepancy exists between intraoperative and postoperative findings, and that intraoperative findings cannot reliably predict long-term results. This study aims to determine whether this discrepancy exists and to assess whether it is possible to predict follow-up results using intraoperative transesophageal echocardiography.

METHODS

A retrospective analysis was made in 35 patients who underwent biventricular repair by one surgeon between November 1997 and January 2004. All patients received intraoperative transesophageal echocardiography and follow-up transthoracic echocardiography at 19.1 +/- 18.02 months (range, 7 days to 5 years; median, 15.1 months).

RESULTS

In left-sided atrioventricular valve regurgitation, 34.3% (12 of 35) of patients showed discrepancy during follow-up, and 28.6% (10 of 35) showed progression of regurgitation (from grade I to II). In right-sided atrioventricular valve, 11.4% (4 of 35) of patients showed discrepancy, 9.6% (3 of 35) showed progression of regurgitation (from grade I to II).

CONCLUSIONS

In complete atrioventricular septal defects, intraoperative transesophageal echocardiography did not show the same findings as that of follow-up transthoracic echocardiography in some cases. However, this discrepancy is not so great as to require reoperation in early to midterm follow-up. Therefore, intraoperative transesophageal echocardiography may be used as tool to predict durability of surgical results and to decrease the incidence of reoperation in complete atrioventricular septal defects.

Repair of complete atrioventricular septal defects in patients weighing less than 5 kg

BACKGROUND

The aim of this study was to evaluate the impact of weight less than 5 kg at operation on mortality and morbidity in patients with atrioventricular septal defect (AVSDc) undergoing total correction.

METHODS

Between January 1990 and December 2002, 190 consecutive patients with AVSDc underwent total biventricular correction. They were divided into two groups: group I (n = 64 patients weighing < 5 kg) and group II (n = 126 patients weighing > 5 kg). Associated major cardiac malformations were found in 49 (25.8%) patients. Associated left atrioventricular valve (LAVV) malformations were found in 35 (18.4%) patients. The mean follow-up time was 4.1 +/- 2.9 years (range 2 months-10.7 years).

RESULTS

The in-hospital mortality in group I was 7.8% (5 patients) versus 8.7% (11 patients) in group II (p = 0.95). Major associated cardiac malformations (p < 0.001) and pulmonary hypertension (p = 0.006) were found to be strong predictors for poor postoperative survival. At discharge the mean LAVVR grade in group I was 1.45 +/- 1.2 versus 1.2 +/- 1 in group II (p = 0.13). The actuarial overall survival rates at 1, 3, 5, and 7 years were 96.5%, 92.5%, 91.5%, and 89% respectively and the actuarial overall reoperation free survival rates at 1, 3, 5, and 7 years were 95%, 87%, 84%, and 73%. Twenty-three patients underwent reoperation due to severe left atrioventricular valve regurgitation (LAVVR). Strong predictors for overall reoperation free survival were the operation year before 1995 (p < 0.001), postoperative LAVVR greater than or equal to 2 (p = 0.006), major associated cardiac malformations (p = 0.00034), associated LAVV malformations (p = 0.0044), and non or partial LAVV cleft closure (p = 0.012). The actuarial survival rates between patients weighing less than 5 kg versus patients weighing more than 5 kg were similar (p = 0.51); instead the overall reoperation free survival was significantly lower in patients weighing less than 5 kg (p = 0.022) according to the log-rank test. Weight less than 5 kg (p = 0.023, beta = -0.6) was one of the predictors for reoperation due to severe LAVVR in this series.

CONCLUSIONS

We may conclude that in the current era repair of AVSDc can be carried out successfully in patients less than 5 kg, however, weight less than 5 kg at initial complete repair seems to be a predictor for late reoperation due to LAVVR. Suture separation at the cleft site or between the leaflets of the newly created mitral valve and the patch remain the main causes of postoperative LAVVR in patients weighing less than 5 kg.

Complete versus partial atrioventricular canal: equal risks of repair in the modern era

OBJECTIVE

To assess the authors' hypothesis that with modern techniques, the current risks of repair for both complete and partial atrioventricular canal (AVC) are equal.

SUMMARY BACKGROUND DATA

Repair of complete AVC in infancy has traditionally carried a substantial mortality. In contrast, partial AVC has been considered low-risk for repair and can be performed later in childhood.

METHODS

This was a retrospective review of 63 infants and children who underwent complete (n = 40) or partial AVC repair (n = 23) from 1990 to 2001. Among complete AVC patients, the ventriculoseptal defect was repaired via an individualized approach according to each patient's specific anatomy: direct suturing without a patch (n = 5) and/or interposition of a small pericardial patch with a running suture (n = 35). In all 63 patients the left AV valve cleft was closed with interrupted sutures, and all atrial defects were closed with a pericardial patch. Data were analyzed with the Student test and Fisher exact test.

RESULTS

Results are expressed as the mean +/- SEM. Age at operation was 6.3 +/- 2.0 months for complete AVC and 47.5 +/- 6.1 months for partial AVC (P <.001). Bypass time was 65.2 +/- 2.3 minutes for complete AVC and 58.3 +/- 3.9 minutes for partial AVC ( P=.1). Reoperation rate was 7.5% (3/40) for complete AVC and 13.0% (3/23) for partial AVC ( P=.6). Early mortality was 2.5% (1/40) for complete AVC and 0% (0/23) for partial AVC ( P=.6).

CONCLUSIONS

Compared to partial AVC, patients presenting for complete AVC repair are significantly younger and manifest more complex anatomy and pathophysiology. However, utilizing modern techniques, including an individualized surgical approach to the ventricular component, repair of complete AVC yields reoperation and early mortality rates similar to those of partial AVC.

The challenge of pediatric cardiac services in the developing world

Pediatric cardiac services are too expensive for most developing nations. Problems other than cardiac disease take priority when it comes to budget allocations. Poor health infrastructure and referral systems, malnutrition, and the HIV/AIDS pandemic aggravate the situation, and the increasing economic divide is threatening what services do exist. We highlight how the practice of pediatric cardiac surgery in South Africa compares with first-world standards and outline some of the problems faced by pediatric cardiac services in developing nations.

A modified 'single patch' technique for complete atrioventricular septal defect correction

We propose a modified single-patch technique consisting in plication of the patch on the left side, which then is sutured with the free edge of the left atrioventricular valve. The proposed technique offers all the advantages of the single-patch technique and at the same time provides additional tissue for reconstructing appropriately the left atrioventricular valve in cases with leaflet tissue deficiency such as severely dysplastic valve, double orifice left atrioventricular valve. This modification augments the left atrioventricular valve tissue appropriately to the orifice size, promotes leftward displacement and improved coaptation with the mural leaflet.

Surgical repair of complete atrioventricular septal defect

BACKGROUND

The objective of this study was to assess the outcome of complete atrioventricular septal defect repair from 1981 to 2000.

METHODS

One hundred seventy-two consecutive patients with atrioventricular septal defect were operated on by a single surgeon using a consistent operative technique (single patch; "cleft" closure). The patients' age range was from 5 weeks to 9 years (mean, 10.8 +/- 1.2 months).

RESULTS

Overall operative mortality was 15 of 172 (8.7%) and this decreased significantly from 12 of 73 (16.4%) in the first decade to 3 of 99 (3.0%) in the second decade (p = 0.0021) with no operative deaths in the last 51 patients. Operative mortality was related to decade of operation (p = 0.0021) and to use of crystalloid cardioplegia (p = 0.0047) by univariate analysis, and to decade of operation (p = 0.0016) and postoperative time on ventilator (p = 0.0023) by multivariate analysis. Actuarial long-term survival including operative deaths was 79.0% +/- 3.8% at 15 years. Ten of 157 (6.4%) operative survivors have undergone reoperation for late mitral regurgitation (9 mitral valve repair, 1 mitral valve replacement) with one death. Four of 8 patients surviving late mitral valve replacement have subsequently required mitral valve repair. Freedom from late reoperation for severe mitral regurgitation was 89.9% +/- 3.1% at 15 years. Freedom from late reoperation for mitral regurgitation did not decrease in the second decade (84.2% +/- 6.6% at 10 years) versus the first decade (94.5% +/- 3.1%) (p = 0.0679).

CONCLUSIONS

Although operative mortality for repair of atrioventricular septal defect has decreased dramatically during the past decade, the incidence of late reoperation for mitral regurgitation has not improved, and better techniques to eliminate late mitral regurgitation are needed.

Direct closure of ostium primum defect in the repair of atrioventricular septal defect

BACKGROUND

Patch closure is generally performed for atrial septation of an atrioventricular septal defect. We recently developed a new surgical technique for repairing atrioventricular septal defects that avoids the use of any patch material for closing the atrial septal defect. We report our experience with this procedure.

METHODS

Seven patients (complete type: 5, partial type: 2) underwent this new operation. The diameters of the atrial septal defects were measured by transesophageal echocardiography. The preoperative electrocardiograms were compared with those taken after the operations.

RESULTS

Diameters of the atrial defects ranged from 3 to 10 mm. Electrocardiograms before and after the operations did not change. No significant atrioventricular valve regurgitation and no residual shunts were detected by postoperative echocardiography.

CONCLUSIONS

This method simplifies the repair of atrioventricular septal defects. In the short-term results, no arrhythmia and no valve regurgitation was seen.

Simplified single patch technique for the repair of atrioventricular septal defect

OBJECTIVE

Because of the complexity of traditional 1- and 2-patch techniques for the repair of complete atrioventricular septal defect, we modified our repair technique to avoid the use of any ventricular septal patch material. We report our prospective experience with this simplified 1-patch technique.

METHOD

Forty-seven consecutive patients between May 1995 and August 1998 underwent repair with the use of this technique without modification. Repair was done in all patients by direct suturing of the common atrioventricular valve leaflets to the crest of the ventricular septum. No division of valve leaflets was necessary. A single pericardial patch was used to close the defect in the atrial septal component. Follow-up included electrocardiography and echocardiographic assessment of ventricular function, atrioventricular valve function, and adequacy of the left ventricular outflow tract.

RESULTS

There were 2 deaths (4%), only 1 cardiac related, in the series. There were 17 male patients and 30 female patients. Mean age at repair was 5.6 months (median, 3.4 months). Associated lesions were repaired in 19 patients (40%). Mean follow-up was 1.85 years (median, 1.9 years). There was no heart block. There were no significant residual ventricular septal defects detected and no left ventricular outflow tract obstruction seen on echocardiography in any patient to date. Mitral valve status after operation was assessed as no incompetence in 13 patients (28%), minimal in 19 patients (40%), mild in 12 patients (26%), and moderate in 3 patients (6%).

CONCLUSION

The repair of complete atrioventricular septal defect by direct suturing of the atrioventricular valve leaflets to the crest of the ventricular septum with a single-patch technique greatly simplifies the repair and does not lead to left ventricular outflow tract obstruction nor interfere with valve function.

Interventricular communication in complete atrioventricular septal defect

BACKGROUND

Little attention has been paid to whether the interventricular communication in complete atrioventricular septal defect is different beneath the superior and inferior bridging leaflets, a feature of obvious surgical significance.

METHODS

We searched for a defect under the bridging leaflets and examined the valve morphologies in 98 autopsied and 86 surgical patients. Of the overall specimens, 27 were associated with Fallot's tetralogy, and a further 20 had subaortic stenosis, aortic coarctation, or both. In the autopsied specimens, we also measured the degree of deficiency of the ventricular septum.

RESULTS

No communication was found under the inferior bridging leaflet in 30% (29 of 98) of the specimens. All 29 hearts except two without such communications showed an undivided inferior leaflet. In contrast, all patients undergoing operation except 1 had a communication beneath both bridging leaflets (p < 0.001). The absence of a communication beneath the inferior leaflet was observed more in hearts with Fallot's tetralogy (seven of 14) or those with subaortic stenosis, aortic coarctation, or both (eight of 18) than in those without associated anomalies (14 of 66; p < 0.01). Those with a communication under the inferior leaflet showed a greater deficiency of the inlet ventricular septum than did those without it (p < 0.001).

CONCLUSIONS

In a certain percentage of patients with complete atrioventricular septal defect, there will be no communication under the inferior bridging leaflet. Surgeons should be aware of this possibility, particularly when confronted with a patient with obstruction in either ventricular outlet.

Primum atrial septal defect in children: early results, risk factors, and freedom from reoperation

BACKGROUND

Repair of primum atrial septal defect in children usually is associated with a low operative mortality, except for a subgroup of children with congestive heart failure. To determine the early mortality and incidence of reoperation in children with primum atrial septal defect, we analyzed retrospectively the results of patients who underwent repair of this defect.

METHODS

Between July 1982 and December 1996, 180 children underwent repair of primum atrial septal defect. The mean age at repair was 4.6 years (median, 3.6 years; range, 1 month to 16.4 years); of the 180 children, 23 were infants less than 1 year of age. Absent or mild symptoms were present in 145 (80%), whereas 34 (20%) of children presented with severe symptoms or congestive heart failure.

RESULTS

Early mortality occurred in 3 (1.6%); 2 were less than 1 year of age. Follow-up ranged from 2 months to 14.5 years (mean, 6 +/- 4.2 years). Actuarial survival is 98% at 10 years with no late deaths. Age less than 1 year is a predictor of death. During follow-up, 17 (9%) of the 180 patients underwent reoperation, 5 of whom were in the infant group. Five underwent reoperation for subaortic obstruction, and 12 for left atrioventricular valve regurgitation of whom 11 were repaired; and 1 required valve replacement. Age and preoperative moderate-to-severe left atrioventricular valve regurgitation were predictors of reoperation.

CONCLUSIONS

Results of the repair of primum atrial septal defect during childhood are favorable. Infants have a higher risk for death and reoperation. Left atrioventricular valve insufficiency and subaortic stenosis are important late complications and can be repaired safely at reoperation.