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Eur J Cardiothorac Surg 2000;18:473-479
© 2000 Elsevier Science NL

Results of primary two-patch repair of complete atrioventricular septal defect

^a Department of Cardio-thoracic Surgery, University Hospital Rotterdam, Rotterdam, Netherlands
^b Department of Clinical Epidemiology, University Hospital Rotterdam, Rotterdam, Netherlands
^c Department of Pediatric Cardiology, University Hospital Rotterdam, Rotterdam, Netherlands

Received 6 September 1999; received in revised form 5 June 2000; accepted 12 July 2000.

Corresponding author. Tel. +31-10-4635412; fax: +31-10-4633993
e-mail: klomp{at}thch.azr.nl

	Abstract

Top Abstract 1. Introduction 2. Materials and methods 3. Results 4. Discussion Appendix A. Conference... References

 
Objective: The policy of primary repair of complete atrioventricular septal defect (CAVSD), using a two-patch technique, was evaluated with special attention to the risk of implantation of a prosthetic atrioventricular (AV) valve. Methods: From 1986 to 1999, all 97 patients who underwent primary repair for CAVSD were included in a retrospective analysis. Seventy-five patients (75%) had Down's syndrome. Preoperative echocardiographic AV valve regurgitation was absent or limited in 85 (88%), moderate in seven (7%) and severe in five (5%). Fifty-six patients (58%) were on diuretics, six (6%) on artificial ventilation and four (4%) were on inotropic support. The mean age at operation was 10.2 months (SD, 16.4), with a mean weight of 5.9 kg (SD, 3.7). Results: Early mortality comprised three patients (4%), and late mortality two patients. Follow up was complete and comprised 402 patient-years (mean, 4.5 years; SD, 3.2). The cumulative survival at 10 years was 93% (95% CI, 89–97%). Multivariate analysis with regard to mortality revealed no associations with any of the analyzed factors. Eight patients were reoperated, all for regurgitant left AV valve. The reoperation-free survival at 10 years was 83% (95% CI, 75–91%). Multivariate analysis with regard to reoperation showed being on preoperative diuretics to be a decreasing risk factor (Odd's Ratio (OR), 0.13; 95% CI, 0.00–0.99; P=0.005) and significant postoperative left AV valve regurgitation to be an increasing risk factor (OR, 9.90; 95% CI, 1.90–53.0; P=0.001). Only one prosthetic valve was implanted (annual linearized risk of 0.002/patient-year). At the latest follow up of the surviving patients, left AV valve regurgitation was absent or limited in 83 (90%) and moderate in nine (10%). Right AV valve regurgitation was absent or limited in all 92 (100%) patients. All surviving patients are thriving well, seven (8%) of whom are on diuretics. Conclusions: Primary repair of CAVSD with a two-patch technique, including cleft closure of the left AV valve, has good clinical and functional results without problems for the right-sided AV valve. The need for prosthetic valve implantation for the left AV valve is minimal.

Key Words: Complete atrioventricular septal defect • Primary repair • Bridging leaflet separation • Two-patch technique

	1. Introduction

Top Abstract 1. Introduction 2. Materials and methods 3. Results 4. Discussion Appendix A. Conference... References

 
The surgical strategy with regard to complete atrioventricular septal defect (CAVSD) has converged to primary complete repair at 3–6 months of age [1–6]. Not infrequently, however, the results of this approach are somewhat obscured in the literature, because most surgical reports also include previously banded patients [1–5,7,8]. This present day policy of primary repair of CAVSD has a limited early mortality and accomplishes adequate functional results [3,6,9,10]. In the long term, the reconstructed left atrioventricular (AV) valve performs well, especially since the recognition that cleft closure contributes positively to these results [1,3,6–9]. However, these results can only be accomplished with a certain number of reoperations and sometimes prosthetic valve implantation can not be avoided [1,3,8,11].

Despite an ever increasing knowledge on the function of the left AV valve after surgery for CAVSD [5,7,9,11], information on the right AV valve is scarce. Although the long-term results of reconstruction of the right AV valve do not pose a clinical problem, detailed information on postoperative valve function is not readily available [12].

The policy of primary repair of CAVSD, using a two-patch technique with cleft closure on both the left and right AV valves, was evaluated with special attention for the function of the left and right AV valves and for the risk of prosthetic AV valve implantation.

	2. Materials and methods

Top Abstract 1. Introduction 2. Materials and methods 3. Results 4. Discussion Appendix A. Conference... References

 
From 1986 to 1999, all 97 patients who underwent primary biventricular repair for CAVSD were included in a retrospective analysis. In all these patients, a shunt at a ventricular level below the common AV valve was present, and the superior and inferior leaflets were not attached to each other. Additional anomalies other than CAVSD were exclusion criteria. Eleven patients with imbalanced ventricles, all right-dominant, are included. During this period, no CAVSD patients were initially palliated with banding of the pulmonary artery, nor were any Fontan-type operations carried out in this group. The mean age at operation was 10.2 months (SD, 16.4; range, 1.6–99.1); 57 patients were younger than 6 months of age. The mean weight at operation was 5.9 kg (SD, 3.7; range, 3.0–29.0). Seventy-five patients (75%) had Down's syndrome. In all patients, the diagnosis was made on echocardiography. On preoperative echocardiography, AV valve regurgitation was absent or limited in 85 (88%), moderate in seven (7%) and severe in five (5%). At present, preoperative diagnostic studies are exclusively done by echocardiography. In the early part of the series, an additional cardiac catheterization was carried out on 33 patients. Fifty-six patients (58%) were on diuretics, six (6%) on artificial ventilation and four (4%) on inotropic support.

Surgery was performed using continuous extracorporeal circulation with moderate hypothermia (rectal temperature, 28°C) and cardioplegic arrest (a single antegrade dose of St. Thomas Hospital Cardioplegic solution, 10 ml/kg body weight). The surgical reconstruction consists of a two-patch technique. All operations were done through a right atriotomy parallel to the right AV groove, extending from the right atrial auricle to the level of the entrance of the inferior caval vein. The retrospective data on AV valve morphology recognized Rastelli type A in 31 patients, type B in 21 and type C in 45, of which 20 were free floating [13]. In one patient, a double orifice of the inferior bridging leaflet was registered. In three patients, a diminutive or absent left lateral leaflet was registered. Cold saline solution was used to fill the ventricular chambers and float the AV valve tissue into a closed position to establish the line of coaptation between the superior and inferior components of the valve and to identify the proper line of division into right and left parts of these components in Rastelli types B and C (Fig. 1a,b) . In Rastelli type A, no surgical division is necessary. The chordal anatomy is left intact.

View larger version (88K): [in this window] [in a new window]   Fig. 1. (a) View through a right atriotomy (ra), atrial septum not drawn, coronary sinus (cs) indicated. The superior and inferior bridging leaflet (sbl, ibl) are divided at the proper line in Rastelli types B and C. In Rastelli type A, no surgical division is necessary. (b) Exposure of the VSD. (c) The VSD is closed by sewing in a semi-oval Gore-Tex patch onto the right side of the defect with a running suture. (d) At the AV level, the superior bridging leaflet and the right superior leaflet in Rastelli type A and the respective parts of both superior and inferior bridging leaflets in Rastelli types B and C are included in the running suture line and sewed to the VSD patch, taking care of adequate coaptation at the meeting point of the superior and inferior leaflets on both the right and left sides. (e) Closing of the ASD is started with a running suture to fix an autologous pericardial patch, starting in the commissure between the right mural leaflet and the inferior bridging leaflet, following the hingepoint level of the leaflet, and continuing onto the previous suture line at the AV level of the VSD patch. After repair of the left AV valve, the closure of the ASD is completed by further sewing in the pericardial patch. From the commissure between the right mural leaflet and the inferior bridging leaflet, the patch follows the right atrial wall to the bottom of the coronary sinus in order to avoid the AV nodal area with preservation of coronary sinus drainage to the right atrium. From this point on the border of the ASD is followed to reach superiorly the AV ring again. If indicated, the right-sided AV valve is now repaired.

The ventricular septal defect (VSD) was closed by sewing in a semi-oval Gore-Tex patch (Gore, Flagstaff, NJ) onto the right side of the defect with running 5.0 Surgilene (American Home Products, Madison, NJ; Fig. 1c). At the AV level, the superior bridging leaflet and the right superior leaflet in Rastelli type A and the respective parts of both superior and inferior bridging leaflets in Rastelli types B and C were included in the running suture line and sewn to the VSD patch, taking care of adequate coaptation at the meeting point of the superior and inferior leaflets on both the right and the left sides (Fig. 1d). Closure of the atrial septal defect (ASD) was begun with a running Prolene (Johnson and Johnson, New Brunswick, NJ) to fix a glutaraldehyde-pretreated autologous pericardial patch, starting in the commissure between the right mural leaflet and the inferior bridging leaflet, following the hingepoint level of the leaflet and continuing onto the previous suture line at the AV level of the VSD patch (Fig. 1e). At this stage, the suturing at the left AV valve circumference at septal level is complete and valve testing can be done. Using horizontal interrupted sutures Prolene 6.0, the left-sided cleft was then completely closed in patients with a tri-leaflet left AV valve after reconstruction, or partially closed in patients with bi-leaflet left AV valve in the absence of a left lateral leaflet. Effectively, the left-sided cleft was closed in 80 patients (82%). Valve competence was repeatedly tested with saline injection through the valve orifice. If considered indicated, commissuroplasty was applied. On the left-sided AV valve this was done in 34 patients (35%). Elongation of the base of the left superior and inferior leaflets [3] was not applied in our series, nor were chordal plasty or transfer. The closure of the ASD was then completed by further sewing in the pericardial patch. From the commissure between the right mural leaflet and the inferior bridging leaflet, the patch follows the right atrial wall to the bottom of the coronary sinus in order to avoid the AV nodal area with preservation of coronary sinus drainage to the right atrium (Fig. 1f). Nevertheless, in the early part of the series, the coronary sinus drainage was put to the left in seven cases. From this point on the border of the ASD was followed to reach superiorly the AV ring again. In case of a second ASD, both were closed with the pericardial patch. The right AV valve was floated into a closed position, and, if indicated, the right-sided coaptation area of the superior and inferior bridging leaflets was closed with interrupted Prolene 6.0 sutures (Fig. 1e). This was done in 44 patients (45%). Commissuroplasty on the right-sided AV valve was done in only two patients (2%).

The mean cardiopulmonary bypass time was 106 min (SD, 26; range, 71–195 min). The mean aortic crossclamp time was 71 min (SD, 17; range, 43–146 min). After bypass, epicardial or transesophageal echocardiography is applied to evaluate the reconstruction.

In the postoperative period, pulmonary hypertensive episodes were registered in five patients. The mean duration of postoperative ventilation was 2.2 days (SD, 2.8; range, 1–15). Seventy-three patients were ectubated on the first postoperative day. The mean duration of intensive care stay was 3.7 days (SD, 5.5; range, 1–42). Seventy-six patients left the intensive care within 2 days.

Follow up was completed with the end of medical records and echocardiographic reports on the last visit to the outpatient clinic.

The statistical methodology uses means, SDs and ranges where appropriate. The association of clinical characteristics with mortality or reoperation was tested univariately by means of odd's ratios and multivariately with the Cox proportional hazard model. A P value of smaller than 0.05 is regarded as significant. Survival and freedom of reoperation were analyzed according to Kaplan–Meier estimates with 95% CIs.

	3. Results

Top Abstract 1. Introduction 2. Materials and methods 3. Results 4. Discussion Appendix A. Conference... References

 
Early mortality comprised three patients (3%). Two patients died due to an intractable pulmonary hypertensive reaction at 0 and 10 days after operation, respectively, and one patient died 9 days after operation due to multi-organ failure. Late mortality occurred with two patients, one died suddenly at home after 1.5 months in acute respiratory failure, one died after 5.5 years in chronic cardiac failure. This last patient postoperatively required a permanent pacemaker for total heart block. He had a mild left AV valve regurgitation directly after operation, which later developed into moderate to severe. At 4.5 years, a failed attempt at valve repair was done with subsequent implantation of a St. Jude 27 mitral valve prosthesis (St. Jude Medical, St. Paul, Minneapolis, MN). In the other four patients, regurgitation of the left AV valve before death was absent or mild in three and severe in one.

Follow up was complete and comprised of 402 patient-years (mean, 4.5 years; range, 0.4–12 years). The cumulative survival at 10 years was 93% (95% CI, 89–97%; Fig. 2) .

View larger version (7K): [in this window] [in a new window]   Fig. 2. Cumulative survival after primary correction of CAVSD. The vertical axis is truncated for graphical reasons.

View larger version (8K): [in this window] [in a new window]   Fig. 3. Cumulative freedom from death and reoperation after primary repair of CAVSD. The vertical axis is truncated for graphical reasons.

Univariate analysis with regard to reoperation revealed possible beneficial effects of being on diuretics preoperatively (OR, 0.09; 95% CI, 0.01–0.75; P=0.007) and closing the left-sided cleft (OR, 0.17; 95% CI, 0.04–0.77; P=0.01), and possible negative effects of division of the inferior bridging leaflet (OR, 0.09; 95% CI, 0.01–0.75; P=0.007), postoperative left-sided AV valve regurgitation (OR, 11.11; 95% CI, 1.90–100.0; P=0.0005) and the occurrence of postoperative pulmonary hypertensive events (OR, 0.07; 95% CI, 0.04–0.15; P=0.05; Table 2).

	4. Discussion

Top Abstract 1. Introduction 2. Materials and methods 3. Results 4. Discussion Appendix A. Conference... References

 
The results of CAVSD repair have improved, as evidenced by a decline of early mortality for primary repair to 2–5% [3–6,7,9]. The estimates of survival 10 years after repair of CAVSD are reported as 78–91% [3,4,6,7,9], with a freedom from any reoperation of 83–95% [3,4,6,9]. Although the preferred age at operation is often advocated as 3–6 months of age, the realized figures frequently show a higher age at operation [6,9]. In our series, 57 patients (59%) were operated under the age of 6 months, but age at operation was not correlated, negatively or positively, with outcome, as measured by death or reoperation.

In our institution, these results were accomplished by a modified two-patch technique. With appreciation of the presence of an indentation in the superior (Rastelli type A) and inferior bridging leaflets, division of the superior (Rastelli types B and C) and inferior bridging leaflets was routinely applied in our series. Our technique of operation provides superior access to all margins of the VSD, and allows ample orientation cranially on the left ventricular outflow and the aortic valve and caudally on the conduction axis. No weaving in between chordae is necessary. In addition, our protocol includes the closure of the cleft on the left AV valves. Our technique is safe, and the technical aspects of our surgical technique were not a risk factor as evidenced in the multivariate analysis of death and reoperation.

Failure of repair of the left AV valve is still an important factor in early mortality [1,3,4,7,9]. Significant early left AV valve regurgitation is an indication for early reoperation, especially because remarkably often the valve can be additionally repaired [1,3,4,6,7,9,11]. The incidence of early reoperation for regurgitant left AV valve is being reported as 2–12% [1,7–9,11]. This was confirmed in our series. We confirm that early AV valve regurgitation is correlated with not closing the left-sided cleft at correction. This caused most of the reoperations resulting from corrective surgery in the early part of the series, when some of these clefts were left untouched. The risk of early reoperation for regurgitant AV valve, is also reported to be increased in the presence of additional valvular anomalies, such as a double orifice left AV valve [7,9,11]. We confirm that severe regurgitation of the left AV valve is a risk factor for early reoperation [7,9], although this is not a uniform finding [5]. In addition, we found no correlation between reoperation for regurgitant AV valve and Rastelli type [7,9,13].

At reoperation, the regurgitant left-sided AV valve, most often, can again be repaired. However, every now and then, the implantation of a prosthetic valve is necessary. The risk of a left-sided prosthetic AV valve was 0.002/patient-year in our series, and can be deduced from other series as 0.003–0.006/patient-year [3,9]. Freedom from left AV valve replacement at 10 years is reported as 90% [3]. The prosthetic valve in our series was only 1 year in situ, the patient died 1 year after prosthetic valve implantation in chronic cardiac failure.

We confirm that right AV valve regurgitation is a rare cause for reoperation after repair of CAVSD. This did not occur in our series. Right AV valve regurgitation may be more frequent in patients with persistent pulmonary hypertension or right ventricular dysfunction in the course of associated tetralogy of Fallot [12].

We conclude that in primary repair of CAVSD with a two-patch technique, AV valve repair at leaflet level, including routine cleft closure on the left AV valve, has good clinical and functional results and needs a minimal number of prosthetic valve implants. Most long-term survivors have minimal or no regurgitation of either AV valve.

	Footnotes

 
Presented at the 13th Annual Meeting of the European Association for Cardio-thoracic Surgery, Glasgow, Scotland, UK, September 5–8, 1999.

	Appendix A. Conference discussion

Top Abstract 1. Introduction 2. Materials and methods 3. Results 4. Discussion Appendix A. Conference... References

 
Dr D. DiCarlo (Rome, Italy): Please comment on your techniques of closing the cleft because we would seem to have a lot of dehiscence nowadays.

Dr Bogers: In our series there were only three patients who had a dehiscence of the cleft from the original operation. In the early part of the series, there were also a few clefts left open. At reoperation, we closed the total number of eight of these clefts. This was done by interrupted single Prolene sutures.

Dr T. Ebels (Groningen, The Netherlands): If I understood correctly, you divide the bridging leaflets and then use two patches. Can you explain to me the technical advantage of using a two-patch technique while dividing the leaflets? Because usually when one divides leaflets, one uses just one patch.

Dr Bogers: All the different techniques are applied for the same reason, to have a good exposure of what we are doing. In this regard, I reported that there, for instance, were no residual VSDs and we had no reoperation for an LVOT obstruction. And I think, that at least in part, that is because the exposure is optimal in this way.

	References

Top Abstract 1. Introduction 2. Materials and methods 3. Results 4. Discussion Appendix A. Conference... References

 

1. Backer C.L., Mavroudis C., Alboliras E.T., Zales V.R. Repair of complete atrioventricular canal defects: results with the two-patch technique. Ann Thorac Surg 1995(60):530-537.
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4. Michielon G., Stellin G., Rizolli G., Casarotto D.C. Repair of complete common atrioventricular canal defects in patients younger than for months of age. Circulation 1997;96(Suppl II):316-322.
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6. Reddy V.M., McElhenny D.B., Brook M.M., Parry A.J., Hanley F.L. Atrioventricular valve function after single patch repair of complete atrioventricular septal defect in infancy: how early should repair be attempted?. J Thorac Cardiovasc Surg 1998;115:1032-1040.[Abstract/Free Full Text]
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8. Ross D.A., Nanton M., Gillis D.A., Murphy D.A. Atrioventricular canal defects: results of repair in the current era. J Card Surg 1991;6:367-372.[Medline]
9. Günther T., Mazzitelli D., Haehnel C.J., Holper K., Sebening F., Meisner H. Long-term results after repair of complete atrioventricular septal defects: analysis of risk factors. Ann Thorac Surg 1998;65:754-760.[Abstract/Free Full Text]
10. Santoro G., Marini B., di Carlo D., Formigari R., Santoro G., Marcelletti C., Pasquini L. Patient selection for repair of complete atrioventricular canal guided by echocardiography. Eur J Cardio-thorac Surg 1996;10:439-442.[Abstract]
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