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Interact CardioVasc Thorac Surg 2007;6:737-740. doi:10.1510/icvts.2007.161778 © 2007 European Association of Cardio-Thoracic Surgery
Surgical treatment of complete atrioventricular septal defect with the two-patch technique: early-to-mid follow-upCardiac Surgery Department, Pro-Cardíaco Hospital, General Polidoro Street 192, Botafogo, Rio de Janeiro, RJ, 22280-000 Brazil Received 19 June 2007; received in revised form 15 August 2007; accepted 17 August 2007
*Corresponding author. Av. Sernambetiba 4.600 Block 5 Apt: 903, Rio de Janeiro, RJ, 22630-011 Brazil. Tel./fax: +55 21 2535 6066.
We report our results on surgical treatment of complete atrioventricular septal defects using the two-patch technique. Forty patients with complete atrioventricular septal defects were operated on in the period from November 1995 to January 2004 and retrospectively analyzed. The age at the time of surgery ranged from 4 months to 20 years (average=18.8±37 months). Their weights ranged from 3 to 39 kg (average=7.6±5.8 kg). Associated tetralogy of Fallot was present in 20% of the cases (8 patients). Monitoring was complete until January 2007, corresponding to a follow-up ranging from 36 to 135 months (average=74±33.7 months). The surgical mortality rate was 2.5% and the hospital mortality rate was 5%. A third patient died from a brain abscess two years after surgery. Over the long-term, two patients needed further operations: one was submitted to mitral plasty due to severe residual mitral insufficiency, one year later; the other underwent a resection of a sub-aortic membrane after three years. Differences were evaluated using the Student-t or Mann–Whitney tests. Surgical treatment of complete atrioventricular septal defect using the two-patch technique results in low morbidity and mortality in early-to-mid term follow-up.
Key Words: Atrioventricular defects; Tetralogy of Fallot; Congenital heart disease
Defects of the atrioventricular septum arise from the abnormal development of the endocardial cushion in the central part of the heart resulting in malformation of the atrial and ventricular septa as well as the mitral and tricuspid valves. Both partial and complete forms are described. In the complete form, the result is an intercommunication between the four cardiac cavities leading to a volume overload in all of them. Around two-thirds of patients suffer from Down syndrome. There may be associated anomalies such as tetralogy of Fallot (TOF), a double outflow tract and systemic venous return anomalies, which all make surgical treatment more difficult [1]. The complete form has a more complex treatment and worse prognosis than the partial form. The two-patch technique was first used by Trusler [2] in 1976. This involves closure of the VSD, implanting the septal part of the atrioventricular valves in the patch, closure of the mitral cleft in the majority of cases and closure of the ASD with a second patch. The mortality rate for surgical treatment classically lies in the 5–10% range [3] but has been improving recently. The coexistence of associated anomalies is a factor that worsens the prognosis. The object of this report is to describe the rationale behind our approach, to find the best way of treating complete atrioventricular septal defects (CAVSD) and to present our findings from 40 cases.
2.1. Patients Forty patients with CAVSD were operated on in the period from November 1995 to January 2004 and retrospectively analyzed. The age at the time of surgery ranged from 4 months to 20 years (average=18.8±37 months) with 62.5% of the patients being less than 1-year-old. Their weights ranged from 3 to 39 kg (average=7.6±5.8 kg). Seventy percent of the patients suffered from Down syndrome. Associated TOF was present in 20% of the cases (8 patients). Four (10%) patients had already undergone earlier palliative surgical procedures (three Modified Blalock-Taussig and one pulmonary artery bandaging). The Rastelli classification of the cases was A: 25/40 (62.5%), C: 15/40 (37.5%). The patients have been fully monitored through to January 2007, corresponding to a follow-up ranging from 36 to 135 months (average=74±33.7 months). The surgical technique chosen for treating the CAVSD in all patients involved the use of two patches. Access is via a median thoracic incision and a full sternotomy (in four patients, surgery was performed with a lower partial sternotomy). Extracorporeal circulation (ECC) is established in the conventional way using the bicaval technique. We always inspect the presence of the associated arterial channel before starting the extracorporeal circulation (ECC). We use moderate hypothermia (25–28 °C). The caval veins were ligated, the aorta was transversally pinched and hypothermic blood cardioplegia was injected into the root of the aorta at 20–30 min intervals. The single atrioventricular (AV) valve was inspected through the right atrium and, after transvalvular injection of saline, we chose the exact place where the single atrioventricular valve is separated into the right (RAVV) and left valves (LAVV). Next the ventriculoseptoplasty was performed attaching a strip of bovine pericardium with a continuous suture and/or separate stitches on the borders of the ventricular sept using polypropylene 6-0. The left and right AV valves were sutured using polypropylene 6-0 at the top of the bovine pericardium pledget. For all the patients in our sample, the cleft of the left AV valve was closed using polypropylene 7-0 cross stitches. Whenever necessary, the LAVV underwent a posterior annuloplasty using a polypropylene 5-0 suture supported on a bovine pericardium pledget. The defect in the atrial septum was corrected also with a strip of bovine pericardium or autologous pericardium using a continuous polypropylene suture. Coronary sinus was placed to drain physiologically in the right atrium in all cases. When there was associated TOF, this malformation was treated during the same surgical procedure. The VSD was closed with a strip of bovine pericardium through the atrium approach without the need to use the ventriculotomy route. The way of treating right ventricle outflow tract obstruction (RVOTO) was in all cases to increase the right ventricle (RV) outflow tract, resection of the muscular trabeculae and position a transannular patch, using a strip of bovine pericardial monocuspid valve if necessary. This transannular expansion was only performed after an evaluation and attempt to preserve the native pulmonary valve. Immediate postoperative care was conducted in the neonatal or adult ICU. Milrinone and dopamine were utilized routinely in all patients. Those who developed pulmonary artery hypertension crisis after surgery received appropriate treatment with nitric oxide inhalation and sildenafil through the naso gastric tube. Patients that kept a moderate to severe MI were discharged using diuretics and oral vasodilators. The averages of the variables of interest are given with their respective standard deviations. As for the comparison between the sub-groups with or without associated TOF, the statistical significance was evaluated using the Student-t or Mann–Whitney tests. The programs used were SPSS 12.0 and Sigma Stat 3.0.
One hundred percent of the cases were followed up to January 2007. The hospitalization time ranged from 4 to 50 days (average=10.3 days), where 58.9% of the patients remained in hospital for fewer than eight days. The surgical mortality rate was 2.5% (one case of low cardiac output syndrome and pulmonary arterial hypertension) and the hospital mortality rate was 5% (one severe case of low cardiac output syndrome, pancreatitis and SIRS). A third patient died from non-cardiac related causes (brain abscess) two years after surgery. Over the long-term, two patients needed further operations: one underwent a mitral plasty due to severe residual mitral insufficiency one year later; the other was re-operated on to resection a sub-aortic membrane after three years. The main results are given in Table 1. The occurrences of residual defects that did not require further surgery are shown in Table 2. The six patients who kept moderate or severe MI were discharged on the use of medication. All of them had dysfunctional common AV valve in the preoperative period. Four of them were classified as Rastelli A and two as Rastelli C. The one with severe MI was the one reoperated, the others were asymtomatic under clinical treatment alone. Associated TOF did not increase mortality or reoperation rates, but postoperative pulmonary insufficiency was more common, as shown in Table 3.
There has been a considerable advance in the surgical treatment of CAVSD over the last few decades. Mortality as low as 3–6% [4, 5] is being achieved not only through changes in the technical procedures, but also because of improved physiological control during ECC, more efficient myocardial protection and better postoperative care. Considering this last topic, the improved management of postoperative pulmonary artery hypertension crisis using nitric oxide and pharmacologic resources decreased significantly the operative mortality. One of the changes in the surgical technique was proposed more than 20 years ago with the use of two patches instead of only one when closing ventricular and atrial septal defects. We report on the experience of the Pró-Cardíaco Hospital over an 8-year period, where only the two-patch technique was used. As for the population studied, we must first stress the patients wide range of ages. Despite the majority being under one year old (62.5%), six patients with CAVSD were of school age when they were operated on and one patient was 20 years old. Of the 40 patients that underwent operations, 37 are still alive (showing an actuarial survival curve of 92.5% after being followed for an average of 74±33.7 months). Of the three deaths, one occurred on the first day after the operation as a consequence of low cardiac output syndrome in an infant with systemic pulmonary arterial hypertension and a history of countless earlier hospitalizations. Another death occurred on the 50th postoperative day due to low cardiac output syndrome, pancreatitis and SIRS. A late death occurred after two years as a result of a brain abscess. There was a need to reoperate on two patients (5%). One of these was due to severe residual mitral insufficiency (MI), and the other, the presence of a sub-aortic membrane. Bando et al. [6] have studied the reoperation risk factors and found that the presence of a double orifice left AV valve, severe preoperative MI, severe MI in the immediate postoperative period and pulmonary hypertensive crisis were significant. In this study, 8.9% of patients needed to undergo reoperations and of these, almost half were due to severe MI, making this the main reason for reintervention. Eighty percent of patients presented none or trivial MI during the postoperative monitoring period. The only case of severe MI in the postoperative monitoring period had already presented severe insufficiency of the common AV valve during the preoperative period. Left AV valve incompetence is a constant concern in both early and late postoperative CAVSD correction. This depends on the prior existence of insufficiency in the common AV valve, the surgical technique chosen and the age of the patient at the time of the surgery [7]. Long-term echo Doppler monitoring of these patients shows that there is a tendency for this insufficiency not to change after the first month of surgery [8]. The other reoperation in our sample was due to sub-aortic membrane restricting output from the left ventricle. We did not classify this as a complication relating to the surgical procedure since the appearance of this sub-aortic membrane is an independent event, related to the treatment of the long, narrow left ventricle outflow tract, which is common in patients with CAVSD. The role of the initial palliative surgery in the form of pulmonary artery bandaging has changed in recent years. There is a trend [9] towards carrying out the definitive repair procedure sooner and without any initial palliative treatment. We do not perform pulmonary artery bandaging as palliative surgery, even on patients with severe CAVSD. The only case in our sample had been transferred from a different institution. The experience of other services shows greater use of this resource (13–45%) [6, 9]. The proportion of patients with CAVSD who also presented TOF was 20%, a higher rate than that found in the literature [4, 5, 9], which ranges from 5% to 10%. Right ventricular outflow tract obstruction with TOF present was treated with a ventriculotomy, resectioning the trabeculae and positioning a transannular patch with a monocuspid valve. When compared to the 32 patients that were suffering from CAVSD alone, these eight patients with associated TOF did not present worse results with respect to both mortality and reoperation as shown in Table 3. Our series may be still too short for definite conclusions on the impact of associated TOF. There is a trend for these patients to be operated on later than those with CAVSD alone. Right ventricular outflow tract obstruction prevents the development of pulmonary artery hypertension (PAH) and enables surgery to be delayed. Pulmonary insufficiency (PI) was, as expected, present only in this sub-group. The echocardiography study in the late postoperative period classified 2/8 (25%) of the cases as having moderate PI and 2/8 (25%) as having severe PI, which is quite common in the transannular treatment. As far as the early palliatives in these eight cases are concerned, three (37.5%) underwent a pulmonary systemic shunt. In our opinion, primary treatment of the lesion must, whenever possible, be given preference. The early palliative not only adds an inherent mortality, but also tends to make definitive surgery more difficult (increasing the level of reoperations) without offering any mortality benefits [10].
The two-patch surgical technique for treating the complete form of atrioventricular septal defect is effective, safe, associated to a low mortality rate and a low need for reoperation on an early-to-mid term follow-up. Associated TOF did not increase mortality or reoperation, but increased postoperative pulmonary insufficiency.
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Abstract
1. Introduction