Eur J Cardiothorac Surg 2008;33:40-47. doi:10.1016/j.ejcts.2007.09.037
Copyright © 2008, European Association for Cardio-thoracic Surgery. Published by Elsevier. All rights reserved.
Biventricular repair in children with complete atrioventricular septal defect and a small left ventricle
Eva Maria Delmo Waltera,*,
Peter Ewertb,
Roland Hetzera,
Michael Hüblera,
Vladimir Alexi-Meskishvilia,
Peter Langeb,
Felix Bergerb
a Department of Cardiovascular and Thoracic Surgery, Deutsches Herzzentrum Berlin, Germany
b Department of Pediatric Cardiology and Congenital Heart Diseases, Deutsches Herzzentrum Berlin, Germany
Received 27 December 2006;
received in revised form 13 September 2007;
accepted 26 September 2007.
* Corresponding author. Address: Deutsches Herzzentrum Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. Tel.: +49 30 4593 2167; fax: +49 30 4593 22100. (Email: delmo-walter{at}dhzb.de).
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Abstract
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Objective: Biventricular repair of complete atrioventricular septal defect (CAVSD) with small left ventricle aims to restore the normal loading conditions of the left ventricle. This report retrospectively evaluates the outcome of biventricular repair in 19 children with CAVSD and a small left ventricle. Methods: Our computer database was searched for all patients with CAVSD operated on between January 1988 and December 2005. Patients who underwent biventricular repair of CAVSD were considered for investigation if they had a preoperative left ventricle-to-right ventricle long axis ratio (LAR) of <1.1 as determined by cardiac catheterization. Results: There were 259 patients who underwent surgical correction of complete atrioventricular septal defect. Nineteen (10.3%) of 184 patients who underwent biventricular repair had small left ventricle based on LAR measurements. These children had no other associated congenital heart anomalies and had no previous surgery. Nine of these children had associated Trisomy 21. There were 10 (52.6%) males and 9 (47.4%) females, with age of 1–210 (122 ± 67) days and weight of 2.5–9.0 (5.26 ± 1.7) kg at surgery. Mean LAR was 0.76 ± 0.14. Two patients (10.5%) died on the 8th and 11th postoperative day, respectively. Both had very small left ventricle (LAR of 0.45 and 0.60, respectively) and received ECMO support for postoperative low output syndrome and intractable pulmonary hypertension. A patient with an LAR of 0.62 who had ECMO support for postoperative myocardial failure underwent successful heart transplantation on the 21st postoperative day. The long-term survivors (89.5%) with LAR > 0.65 had an uncomplicated postoperative course, had undergone regular follow-up (65 ± 36 months) with echocardiographic assessment of the left ventricle, and had good left ventricular function. There was no early reoperation for residual ventricular septal defect, left AV valve regurgitation, or left ventricular outflow tract obstruction. Late reoperation was performed in three patients (17.4%) who underwent mitral valve repair for significant regurgitation in the 18th, 59th, and 87th month postoperatively. Conclusions: Biventricular repair of CAVSD with small left ventricle in infants and children whose LAR is >0.65, although not without risks, improve patients’ functional and clinical status even in long-term follow-up. Particular caution should be taken in patients with LAR of <0.65, since these are patients who may not be amenable to biventricular repair, but for whom univentricular palliation may be more suitable.
Key Words: Atrioventricular septal defect • Small left ventricle • Biventricular repair • Long axis ratio
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1. Introduction
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Surgical correction of complete atrioventricular septal defects (CAVSD) preoperatively diagnosed with small left ventricle (LV) poses a challenge for cardiac surgeons in terms of surgical option. There are as yet no proven guidelines for deciding between biventricular repair and univentricular palliation [1,2], and more than one strategy has been suggested [3–9]. Cohen and Rychik [1] reported a large group of patients with unbalanced AVSD, wherein they used echocardiographic measurements of atrioventricular valve index (AVVI) which is left valve area divided by right valve area. They suggested that only patients with AVVI > 0.67 (balanced) can safely undergo biventricular repair. However, it was also hypothesized that right ventricle (RV) volume overload results in right-to-left septal bowing and contributes to the appearance of a hypoplastic LV, which can actually accommodate a greater potential volume [10]]. Hence, surgical decision-making depends not only on AVVI but also on absolute LV volume and on the potential volume as well. However, the definition of ventricular hypoplasia as determined preoperatively remains unclear, and mainly criteria that have been applied to other conditions with small left ventricles are used [11].
Univentricular palliation is mostly performed to correct unbalanced CAVSD with hypoplastic left ventricle [2,8,10]. We believe that biventricular repair, if feasible, remains a satisfactory option. Hence, we developed a surgical guideline using left ventricle/right ventricle (LV/RV) long axis ratio (LAR) in our institution for the management of CAVSD with small left ventricle and retrospectively analyzed the surgical outcome in 19 patients who underwent biventricular repair.
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2. Patients and methods
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Medical records and computer databases were reviewed at our institution for demographic, perioperative, and outcome data of all patients with CAVSD operated on between 1988 and 2006. Of the 259 children, 184 underwent primary biventricular repair for CAVSD. Nineteen children were considered for retrospective analysis because they had CAVSD with small left ventricle. A small left ventricle is defined on the basis of angiographic measurements based on a model developed at our institution, expressed as the left ventricle/right ventricle long axis ratio <1.1, where the length of the left/right ventricle is measured in the long axis during ventriculography. These children had no additional cardiac anomalies and no previous palliative operations. The left-sided AV valve morphologic features, particularly the shape of the leaflets, the arrangement of the subvalvular apparatus at the ventricular surface of the leaflet, and the pattern of division of the tendinous cords, were specifically noted as they arise from the papillary muscles in the operative records of these 19 patients.
2.1 Angiographic measurements
All 19 patients considered for retrospective investigation had preoperative cardiac catheterization. Measurements of LV-to-RV long axis ratio were matched with intraoperative findings. Ventricular lengths were obtained by measuring the distance from a plane where the left AV valve and right AV valve are on the same level to their respective apices in the long axis (Fig. 1
). Sizes were measured three times from different frames and averaged.
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Fig. 1. Measurements of LV-to-RV long axis ratio (LAR) where ventricular lengths were obtained by measuring the distance from a plane where the left AV valve and right AV valve are on the same level to their respective apices in the long axis.
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2.2 Surgical technique
Repair was performed using continuous extracorporeal circulation with moderate hypothermia (rectal temperature 24–28 °C) in all patients. Myocardial protection was provided with crystalloid cardioplegia. A pericardial patch was harvested at the beginning of the procedure for closure of the atrial septal defect (ASD). All operations were performed through a right atriotomy parallel to the right AV groove, extending from the right auricle to the level of the entrance of the inferior caval vein. The remains of the atrial septum was incised up to the atrial wall to avoid tension and deformation of the left-sided valves which would later provide optimal suspension and mobility of the reconstructed valves (Fig. 2a). Cold saline solution was used to fill the ventricular chambers and float the atrioventricular (AV) valves into a closed position to evaluate valvular anatomy, establish the line of coaptation between the superior and inferior components of the valve, and identify the proper line of division into right and left parts of these components (Fig. 2b). The AV valves basically consisted of five-leaflet common atrioventricular valve, with a common orifice. A stay suture was placed to mark the point that effectively joined the antero-superior and postero-inferior bridging leaflets (Fig. 2c).
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Fig. 2. (a) Exposure of AVSD anatomy, identification of ASD and VSD, and extended atrial septectomy (broken lines). (b) Assessment of the relationship among the common atrioventricular valves by administration of cold saline solution. (c) The AV valves basically consisted of five-leaflet common atrioventricular valves, with a common orifice. A stay suture was placed to mark the point that effectively joined the left superior and left inferior bridging leaflets. (d) VSD closure: To enlarge the orifice of the left AV valve, the ventricular septal patch was placed more to the right of the ventricular crest and the defect closed by sewing more onto the right side of the defect multiple interrupted pledgeted 5-0 Tevdek sutures and individually sutured to the inferior portion of a precisely fashioned semi-oval Weavenit patch. (e) Another set of interrupted sutures was then passed through the superior portion of the VSD patch, which was then sutured through the left superior and inferior leaflets to partition the valve into right and left components. These sutures were then individually passed through the previously harvested and untreated autologous pericardium, which will later be used to close the ASD. (f) Sutures were then tied, which now obliterated the ventricular component of the defect by approximating leaflet tissue to the septal crest. (g) Reconstruction of the left-sided AV valves: The stay suture previously applied to join the left superior and inferior leaflets was then tied. Another stay suture was placed at the point of the first papillary muscle-derived chordal support of the cleft and placed on tension to facilitate apposition of the two leaflet components and avoid purse string-like effect. Closure was done in an interrupted fashion with Prolene 7-0 and reinforced with pericardial pledgets when the leaflet tissue appeared friable. (h) To assess the quality of the valve reconstruction, cold saline solution was injected into the left ventricle, and if necessary, additional interrupted sutures were placed on the cleft. (i) ASD closure: ASD was then closed with the previously harvested untreated autologous pericardial patch with a running 6-0 Prolene suture following the right atrial wall to the bottom of the coronary sinus in order to avoid the AV nodal area and preserve the coronary sinus drainage to the right atrium. (j) Reconstruction of the right-sided AV valves: The central portion of the right superior and inferior leaflets was approximated into a closed position, with interrupted Prolene 6-0 sutures. (k) If indicated, multiple interrupted Prolene 6-0 sutures were applied. (l) Valve competence was repeatedly tested with saline injection through the valve orifice. ASD, atrial septal defect; AV, atrioventricular; AVSD, atrioventricular septal defect; IVC, inferior vena cava; LAVV, left atrioventricular valve; LIL, left inferior leaflet; LLL, left lateral leaflet; LSL, left superior leaflet; LV, left ventricle; AVV, right atrioventricular valve; RIL, right inferior leaflet; RLL, right lateral leaflet; RSL, right superior leaflet; RV, right ventricle; SVC, superior vena cava; VSD, ventricular septal defect.
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Biventricular repair consists of a double-patch technique. To enlarge the orifice of the left AV valve, the ventricular septal patch was placed more to the right of the ventricular crest. Since the ventricular component was small, the ventricular septal defect (VSD) was closed by sewing multiple interrupted pledgeted 5-0 Tevdek sutures (Deknatel division of Howmedica, Inc., New York, NY) more onto the right side of the defect and individually sutured to the inferior portion of a precisely fashioned semi-oval Weavenit patch (Impra, Inc., Tempe, AZ, USA) and then tied (Fig. 2d). The aforementioned patch was inserted cautiously to avoid chordal distortion. Care was also taken to avoid potential conduction tissues. Another set of interrupted sutures were then passed through left superior and inferior common bridging leaflets to partition the valve into right and left components at the points where the leaflets naturally abutted the crest of the interventricular septum, and then through the leading edge of the VSD patch bringing the antero-superior and postero-inferior leaflet components closer together and increasing the area of central coaptation (Fig. 2e). These sutures were then individually passed through the previously harvested and untreated autologous pericardium, which will later be used to close the atrial septal defect. They were then tied, which now obliterated the ventricular component of the defect by approximating leaflet tissue to the septal crest (Fig. 2f). The distance from the left-sided AV valve level to the crest of the interventricular septum was accurately assessed to reconstruct the left-sided AV valves at the appropriate height to avoid left ventricular outflow tract obstruction. The atrioventricular valves were now sandwiched between ventricular and atrial patches with interrupted monofilament sutures. The stay suture joining the left superior and inferior bridging leaflets were then used to initially close the cleft in the anterior leaflet of the left-sided AV valve. Another stay suture was placed at the point of the first papillary muscle-derived chordal support of the cleft and placed on tension to facilitate apposition of the two leaflet components and avoid purse string-like effect (Fig. 2g). In this series of 19 patients, the left-sided AV valves consisted of superior and inferior bridging leaflets with a space (cleft), in between, and a mural (posterior) leaflet. These leaflets were found to be of equal size and uniformly triangular, with their base continuous with the aortic valve through the region of the valvar fibrous continuity. The edges of the cleft component were attached to the crest of the ventricular septum through chordae tendinae, which were neither thickened nor fibrosed. These chordae emerged from each side of the cleft and were inserted into their respective papillary muscles on each side of the left ventricular outflow tract. Hence the superior and inferior leaflets were approximated to a point in which these chordae insert on the leading edge of these leaflets. The cleft between the left-sided superior and inferior bridging leaflets was closed in 11 patients and partially closed in 9 patients because of tissue deficiency (n
= 4) and left-sided obstruction, i.e. membrane or muscular hypertrophy (n
= 5). Thus, when necessary, simultaneous membranectomy and myectomy of the left ventricular outflow tract was performed. Closure was done in an interrupted fashion with Prolene 7-0 (Ethicon, Johnson and Johnson Intl, St. Stevens, Woluwe, Belgium) and reinforced with pericardial pledgets, when the leaflet tissue appeared friable. During cleft closure, a minimal acceptable mitral valve diameter was maintained according to patient age to avoid mitral stenosis. To assess the quality of the valve reconstruction, cold saline solution was injected into the left ventricle, and if necessary, additional interrupted sutures were placed on the cleft (Fig. 2h). Attempts to gain leaflet tissue area for the mitral component, to bring the left superior and inferior leaflet component closer together and to increase the area of central coaptation, were done by extending the atrial septal defect further towards the atrial wall, as previously described (see Fig. 1a), enabling the left-sided AV valve leaflets to fall downward, avoiding restriction of anterior leaflet mobility as well as increasing valve surface area and preventing leaflet puckering, thus improving leaflet coaptation. The atrial septal defect was then closed with the previously harvested untreated autologous pericardial patch with a running 6-0 Prolene suture (Ethicon, Johnson and Johnson Intl, St. Stevens, Woluwe, Belgium) starting in the commissure between the right mural leaflet and the inferior bridging leaflets, hence, avoiding placement sutures along the crura on both sides. Suturing continues following the free edge of the right atrial wall to the bottom of the coronary sinus in order to avoid the AV nodal area and preserve the coronary sinus drainage to the right atrium (Fig. 2i). From hereon, the border of the ASD was followed to reach the superior AV ring again. The right AV valve was floated into a closed position, and, if indicated, the right side coaptation area of the superior and inferior bridging leaflets was closed with interrupted Prolene 6-0 (Ethicon, Johnson and Johnson Intl, St. Stevens, Woluwe, Belgium) sutures (Fig. 2j and k). Valve competence was repeatedly tested with saline injection through the valve orifice (Fig. 2l).
Annuloplasty, commisuroplasty, chordal plasty or chordal transfer, and elongation of the base of the superior and inferior leaflets were not done in this series of patients.
After intracardiac repair had been completed, pulmonary and left atrial monitoring lines were positioned, the patient was rewarmed, and cardiopulmonary bypass was discontinued. Patients in the series were later assessed with transesophageal echocardiography before and after the repair.
The records of follow-up, including echocardiography, were complete. No patient was lost to follow-up.
2.3 Statistical analysis
Data are expressed as the mean ± standard deviation and ranges where appropriate. Early mortality was defined as hospital death or death within 30 days after operation. Categorical variables as well as the association of LV/RV LAR with mortality and reoperations were analyzed with Pearson's chi-square test, two-tailed Fisher's exact tests of the displayed proportions, and odds ratios. The relationship of bypass and ischemic times to mortality and reoperations was analyzed using the Mann–Whitney U-test. The correlation of biventricular repair and LV/RV LAR with mortality and reoperations was analyzed by means of odds ratios. A p-value of 0.05 or less was considered significant. Survival and freedom from reoperation were analyzed according to Kaplan–Meier estimates with 95% CI. A p-value of 0.05 or less was considered significant.
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3. Results
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3.1 Patient demographics
Nineteen patients were identified to have complete atrioventricular septal defect with small left ventricle according to our definition. Nine (47.4%) patients had associated Down's syndrome. There were 10 (52.6%) males and 9 (47.4%) females; age at surgery was 1–210 (122 ± 67) days and weight was 2.5–9.0 (5.26 ± 1.7) kg. Mean left ventricle-to-right ventricle long axis ratio was 0.76 ± 0.14.
3.2 Operative outcome
Mean cardiopulmonary bypass time was 110.8 min + 48.1 (range 44–232 min) while mean aortic cross-clamp time was 62.2 min + 17 (range 15–89 min). Sixteen patients (84.1%) had successful biventricular repair of the defect. These patients had an LV/RV LAR > 0.65 (mean 0.80 ± 11). In three patients (15.2%), who had severe left ventricular hypoplasia (LAR of 0.45, 0.60, and 0.62, respectively), weaning from cardiopulmonary bypass was not possible because of pulmonary hypertension and low output cardiac syndrome. Extracorporeal membrane oxygenation (ECMO) support was then instituted. Two patients (10.5%, LAR of 0.45 and 0.60) died on the 8th and 11th postoperative day, respectively, from intractable pulmonary hypertension. The third patient with an LAR of 0.62 had ECMO support for postoperative myocardial failure and subsequently underwent successful heart transplantation on the 21st postoperative day. This patient is doing well 7 years after transplantation.
3.3 Postoperative outcome
Mean duration of postoperative ventilation was 70.7 h (SD 14.9, range 10–624 h). Sixteen patients (84.1%) were extubated on the first postoperative day. The mean duration of the intensive care stay was 3.2 days (SD 5.2, range 1–26).
Except for one patient, who had temporary AV block grade I postoperatively for 10 h, no patient had rhythm disturbances and all had an uncomplicated postoperative course. All patients were examined in the early postoperative period by echocardiography to determine patch leaks, residual VSD, and left AV valve insufficiency. In discharge echocardiography, three patients had mild mitral valve regurgitation and two patients had mild tricuspid regurgitation. No patient had stenosis of the AV valves (Table 1
).
3.4 Follow-up
The postoperative course of the 17 surviving patients was uncomplicated and they were seen regularly, and transthoracic echocardiography was performed to assess ventricular function, valve function, and the status of the left ventricular outflow tract. There was no reoperation for residual VSD, residual ASD, or subaortic stenosis. The long-term survivors (89.5%) with LAR > 0.65 (0.80 ± 0.11) had undergone regular follow-up with good left ventricular function as assessed by echocardiography.
Follow-up was complete and comprised 1114-month patient-years (mean ± SD: 58.6 ± 9.12 months, range 0–150 months). The cumulative survival at 10 years was 89.5 ± 7.0% (Fig. 3
).
3.5 Mortality
Univariate analysis showed LAR < 0.65 (OR 1.286, 95% CI 1.19-433.75, p
= 0.004); pulmonary hypertensive crisis (OR 12.787, 95% CI 0.000–0.006, p
= 0.000); and ECMO support (OR 8.968, 95% CI 0.003–0.018, p
= 0.001) to be associated with death (Table 2
).
Univariate analysis of death included the factors: gender, age at operation, weight, associated Down's syndrome, left AV valve regurgitation, and prolonged postoperative ventilation. It revealed none of the tested factors to be associated with death. The Mann–Whitney U-test showed no statistical differences in bypass or cross-clamp times with regard to mortality and reoperation (Table 3
).
3.6 Reoperation
Univariate analysis of gender, age at operation, weight, Down's syndrome, LV/RV LAR, prolonged postoperative ventilation and postoperative left side AV valve regurgitation was performed. It revealed postoperative left-sided valve regurgitation as the only independent negative risk factor (OR 16.574, 95% CI 0.000–0.001, p
= 0.000) (Table 4
).
At the latest follow-up, mitral regurgitation was non-existent in 13 (81.25%) patients and mild in 3 (18.75%). Tricuspid valve regurgitation was absent in 14 (87.5%) and mild in 2 (12.5%) patients.
Three patients underwent mitral valve repair for moderate-to-severe mitral valve regurgitation in the 18th, 59th, and 87th month postoperatively, respectively. Reoperation-free survival at 5 years was 84.79 ± 10.3% while event-free survival at 5 years was 75.5 ± 11.0% (Fig. 4
).
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4. Discussion
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This retrospective study demonstrates that small size of the left ventricle in CAVSD may not necessarily be absolute and that the left ventricle has the potential to increase to a size that is sufficient to support the systemic circulation. In this regard, it was surmised that the volume-loaded right ventricle compresses the already small left ventricle, whereas after surgical correction of the CAVSD, primarily because of reversal of septal deviation, the left ventricle is allowed to attain its full status as a ventricle. Preoperative establishment of left ventricular size is definitely required to decide whether univentricular or biventricular repair is indicated. The key parameter, the long axis ratio, is independent of septal deviation; hence, it is not only simple but may also be far better than volumetry with its complex measurements.
Skillful surgical maneuver is a beneficial factor in the increase in LV size, as also reported by van Son et al. [2]. The volume of the left ventricle was increased surgically by attachment of the ventricular septal patch a little more to the right of the ventricular crest than is usually done in the repair of CAVSD, thus contributing to the adequacy in LV size after operation. Precision must be exerted in the sizing of the patch, as oversizing results in patch redundancy with the potential for left AV valve regurgitation. It is our protocol to close the cleft whenever possible. The most controversial issue in the surgical treatment of CAVSD is the necessity of closing the mitral cleft [3]. Although several studies have reported that closure of the cleft can lead to stenosis of the left AV valve orifice, this has not been demonstrated in our series. This was probably the case because an age-related minimal normal valve diameter was used as a guide in all cases during cleft closure to prevent valve stenosis, as was also reported by Alexi et al. [3]. In fact, Alexi et al. [12] in our institution and others stated in their previous study that incidence of left-sided AV valve insufficiency seemed to be higher in patients with an initially unsutured cleft. Thus, we believe that the low incidence of late left-sided AV valve insufficiency may be attributed to routinely suturing the cleft up to the minimal valve diameter and transecting the residual atrial septum.
Avoiding placement of sutures on the crura of the left-sided AV valves during closure of the ASD increases valve surface area and prevents leaflet puckering, thus improving leaflet coaptation. Fraisse et al. [13] have done an extensive study on the pathogenetic features and management of cleft MV, and have stated that cleft mitral valve may represent a ‘forme fruste’ of an AV septal defect. They further stated that in patients with mitral regurgitation and AVSD, the smaller size of the mural leaflet along with two closely spaced papillary muscles may complicate repair and inaccurate cleft approximation may result postoperatively in significant mitral regurgitation or stenosis after insufficient or excessive closure.
Our two-patch technique of operation for biventricular repair provides greater access to margins of the VSD, hence allowing sufficient orientation on the left ventricular outflow, the aortic valve, and the conduction axis. No weaving in between chordae is necessary. We considered our surgical technique to be safe, and its technical aspects were not a risk factor as evidenced in the multivariate analysis of death and reoperation.
The principal determinant of successful biventricular repair of CAVSD with small left ventricle appears to be related to the competence of the left AV valve and LV size. Indeed, at a median follow-up of 58.6 months, 13 patients had no left AV valve regurgitation, 3 had mild regurgitation, and none of the patients had any restriction of inflow or outflow. Significant left AV valve regurgitation is an indication for early reoperation especially because remarkably often the valve can be additionally repaired [12]. Many authors reported that management of left-sided AV valve in the repair of complete atrioventricular septal defects remains an area of controversy. Alexi et al. reported that there are several factors contributing to left AV valve regurgitation besides a cleft that was left open during the operation or a dehiscence of cleft sutures, such as isolated dilatation of the valvar ring, severe valve deformity, dysplastic AV valve with marked loss of leaflet tissue, and double orifice left AV valve. The incidence of early reoperation for regurgitant left AV valve is 2–12% [6]. We confirm in our series that severe regurgitation of the left AV valve is the most important risk factor for reoperation.
Because all 16 surviving children in this series underwent biventricular repair sustained by an adequate left ventricle postoperatively, we were not able to determine the factors related to outcome. The presence of a small left ventricle (LV-to-RV area ratio as low as 0.66) did not preclude successful biventricular repair. LV-to-RV long axis ratio <0.65 in the preoperative angiogram was clearly a predictor of failure. Although our findings cannot be compared directly with that of Cohen and Rychik [1], we agree that the true LV size may presumably be misleading, and our series suggested that the size of the left ventricle may be altered by surgical manipulation.
We therefore agree with van Son et al. that even the diminutive preoperative left ventricular dimensions should not contraindicate biventricular repair, even though the future behavior of the valvular components must regularly be evaluated.
Results of biventricular repair of complete CAVSD with small left ventricle in our series are deemed satisfactory as evidenced by low early mortality, the absence of late mortality, and low incidence of reoperation. The reported incidence of survival 10 years after biventricular repair of CAVSD is 78–91% with freedom from any reoperation of 93%. Although the preferred age at operation is often advocated as 3–6 months of age, the actual figures frequently show a higher age at operation. In our series, 70.9% of patients were operated on below 6 months of age, but age at operation was not correlated negatively or positively with outcome, as measured by death and reoperation.
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5. Limitations
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The retrospective nature of this study imposed several inherent limitations. First, the patient population was small. Second, the technical quality of the angiograms varied. Third, the decision to pursue a biventricular strategy was made by individual surgeons. It is not possible to know what the outcome of children in whom the biventricular approach failed would have been if they had undergone single ventricle palliation. Fourth, comparative preoperative and postoperative echocardiograms and angiograms were not uniformly available in the patients studied. Finally, it could have been better if other parameters to assess absolute and relative LV sizes, including LV end-diastolic/end-systolic volumes, LV-to-RV area ratio, left AV valve-to-total AV valve diameter ratio, LV long dimensions, and LV-to-RV long dimension ratio, were used in consonance with angiographic measurements both pre- and postoperatively.
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6. Conclusions
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In this small series of children with CAVSD with small left ventricle, biventricular repair was successfully accomplished. Based on these results, we conclude that biventricular repair of CAVSD with small left ventricle may be extended to those with LAR > 0.65. Biventricular repair in children with LAR < 0.65, on the basis of our experience, should be used with caution, as it imposes the greatest risk factor for death. Our study has shown that long-term survivors have minimal or no regurgitation of either valve. We also believe that the low incidence of late left-sided AV valve insufficiency may be attributed to routinely suturing the cleft up to the minimal valve diameter and transecting the residual atrial septum. We confirm that right AV valve regurgitation is not a cause of reoperation after repair of CAVSD.
We believe that the lower limit of LV size must be reconsidered in the context of ventricular configuration. Further studies with larger patient populations are needed to determine the value of preoperative LAR in predicting postoperative LV adequacy. This study has broad implications for the management of CAVSD in which the left ventricle is initially judged to be small or even hypoplastic, but for which biventricular repair may be feasible.
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Acknowledgments
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We thank Anne M. Gale, Editor in the Life Sciences, for editorial assistance. We also appreciate the assistance of Julia Stein, Astrid Benhennour, Christine Detschades, Daniela Moeske-Scholz, Heike Schultz, and Helge Haselbach.
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Footnotes
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\#9734; Presented at the Cardiac Surgery in the 3rd Millennium Biological Solutions 1st International Congress under the Auspices, of the European Academy of Art and Sciences in Salzburg. Austria, November 30–December 1, 2005.
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References
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Abstract
1. Introduction
