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Ann Thorac Surg 2002;73:96-101
© 2002 The Society of Thoracic Surgeons

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Original article: cardiovascular

How to diminish reoperation rates after initial repair of tetralogy of Fallot?

^a Clinics for Cardiovascular Surgery, University Hospital, Geneva, Switzerland
^b Pediatric Cardiology, University Hospital, Geneva, Switzerland

Accepted for publication September 14, 2001.

* Address reprint requests to Dr Christenson, Clinic for Cardiovascular Surgery, University Hospital, rue Micheli-du-Crest 24, CH-1211 Geneva 14, Switzerland
e-mail: jan.christenson{at}hcuge.ch

	Abstract

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Background. Complete correction of tetralogy of Fallot has good long-term results. Right ventricular outflow tract obstruction and pulmonary insufficiency occur which require reintervention. The present study evaluated the efficacy of reoperation following complete correction of tetralogy of Fallot, the sites of recurrences and impact of techniques used at first operation.

Methods. Between 1980 and 1999, 501 patients underwent complete correction of tetralogy of Fallot. Reoperation rate was 7.4%. Residual or recurrent right ventricular outflow tract stenosis was seen in 25 patients (68%), and 7 patients (19%) had severe pulmonary insufficiency. Age at redo was 9.1 ± 6.4 years. Restenosis was most frequently observed (75%) at the bifurcation of the pulmonary artery. Extended 1-patch enlargement was used until 1989 and thereafter changed to a 2-patch technique.

Results. Valvar-supravalvar 1-patch technique had a redo rate of 33.3%, compared with 4.3% for the 2-patch technique, p = 0.0264, with excellent freedom from reoperation rate. At reoperation right ventricular-pulmonary artery (RV-PA) conduits managed 29 patients and 3 had supravalvar patch enlargement. Hospital mortality was 5.4% (2 of 37). Twenty-five patients (68%) were in New York Heart Association functional class I to II at end of the follow-up, and none required further interventions.

Conclusions. Redo rate following complete correction of tetralogy of Fallot was 7.4%. Right ventricular outflow tract pathology was the dominant reason for reoperations (86%). At reoperation, RV-PA conduits was the most frequently used technique. Reoperation was efficient in reducing the RV-PA gradient, had low hospital and late mortality. A 2-patch valvar-supravalvar enlargement at first operation reduced the risk for redo in long-term follow-up.

	Introduction

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The surgical approach for correction of tetralogy of Fallot (TOF) have changed considerably since the first successful palliative procedure was performed in 1944 by Blalock and Taussig [1]. It took substantial time before it was fully recognized that there are different types of TOF with variable complexity and severity, requiring modifications in the surgical approach; one fundamental concept must be recognized, namely that the repair must be compatible with a normal tissue and organ growth. It was not until in the 1970s and 1980s that consensus on indications based on anatomy and clinical presentations was reached [2, 3]. In 1999, an international nomenclature and data base in Pediatric Cardiac Surgery was first established [4, 5]. Even though numerous reports in the literature have demonstrated excellent immediate and long-term outcomes after surgical correction of TOF [6–9], this patient group continues to be at risk for long-term mortality (sudden death from arrhythmia) and morbidity such as important tricuspid and pulmonary regurgitation, ventricular septal patch leaks and, perhaps most important, development of right ventricular outflow tract (RVOT) stenosis or obstruction [6–11]. The need for reoperation following surgical correction of TOF may occur early or late, and overall reoperation rates have been reported between 3.3% and 16.5% [12–14].

Since RVOT stenotic lesions are the main reason for reoperation, we have reviewed our experience from 537 patients undergoing surgical correction of TOF. We focused on patients with RVOT lesions, with the plan to modify surgical technique at the primary operation so that late stenotic lesions could be diminished.

	Material and methods

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Patient population
Between January 1, 1980 and December 31, 1999, 537 patients underwent primary surgical correction/repair of tetralogy of Fallot at our institution. Thirty-six (6.7%) of the patients had palliative procedures, while 501 patients underwent complete correction of TOF; this latter group form the basis for this report.

Definition of TOF
Ninety of the patients in this series came from African countries through humanitarian associations. Usually in this population, the mean age at the time of initial repair is higher than that of local patients. In all these cases, the cardiac malformation was characterized by underdevelopment of the right ventricular infundibulum with anterior and leftward displacement of the conal septum and its parietal extension associated with right ventricular outflow tract stenosis and a large subaortic ventricular septal defect (VSD).

The locations of lesions following the Society of Thoracic Surgeons nomenclature were isolated subvalvar (infundibular) lesions in 162 patients (32.2%), subvalvar plus valvar (transannular) lesions were seen in 98 patients (19.6%), while supravalvar in combination with subvalvar or valvar lesions were present in 241 patients (48.1%). Surgical correction of uncomplicated TOF (n = 260 patients, 48.4%) consisted of subvalvar trabecular resection and (a) valvulotomy without subvalvar enlargement in 36 patients and valvulotomy plus transannular patch (TAP) in 111 patients; (b) subvalvar enlargement plus pulmonary valvulotomy in 78 patients; and (c) TAP only in 35 patients. The transannular patch was sized according to Pacifico curve determining the appropriate diameter of the Hegar dilator based on the body surface area. In cases of complex TOF (n = 205 patients, 38.2%), 107 patients had an extended TAP repair and 27 patients with anomalous left anterior descending artery (LAD) had a correction achieved by a double patch procedure.

Thirty-six patients (6.7%) with TOF and pulmonary sub-atresia were managed by right ventricular-pulmonary arterial (RV-PA) conduits; woven Dacron (C. R. Bard, Haverhill, MA) grafts in 5, autologous nonvalvulated grafts in 4, xenograft in 1 and, valved homografts in 26 patients (24 aortic and 2 pulmonary valved homografts). Thirty-four patients have had palliative procedures done prior to the total correction of their TOF (24 had Blalock, 7 Brock, and 3 Waterston operations).

The mean age at time of surgery was 5.3 ± 4.0 years, ranging from 10 hours to 37 years of age. The age distribution is shown in Table 1. The average body surface area (SA) was 0.63 ± 0.21 m², the preoperative PA-RV gradient 70.1 ± 15.2 mm Hg, and cardiac output was 3.92 ± 0.89 L/min. Criteria for reoperation for patients with RVOT stenosis was the presence of a PA-RV gradient greater than 50 mmHg.

The pulmonary artery anatomy is rather peculiar and defined on either different views of catheterization (opacification of the PA) or during operation in cases which were not investigated by catheterization. We observed that only one of the pulmonary artery branches has the same anatomical direction as the main stem of the PA, either the right or the left pulmonary artery (Fig 1). In patients with stenosis of the origin of the left PA or the entire pulmonary artery bifurcation, it appears therefore important to modify the patch enlargement technique used in accordance to the anatomy of the pulmonary arch in each individual case. This led us in 1989 to change our technique accordingly, and to apply a 2-patch enlargement technique in those cases where the right PA had the same direction as the main PA and the left PA took off at a rather acute angle (n = 22), and in those cases where the left PA had the same direction as the main PA and the right PA took off at a rather acute angle (n = 1) (Fig 2).

View larger version (12K): [in this window] [in a new window]   Fig 1. The pulmonary arch morphology. Please note that only one of the pulmonary artery (PA) branches has the same flow direction as the main stem of the PA, either the left PA (I) or the right PA (II).

View larger version (23K): [in this window] [in a new window]   Fig 2. Reconstruction of the origin of the pulmonary artery (PA) branches for patients with left PA stenosis. (a) The left PA has the same axis as the main PA; Surgical technique: 1-patch enlargement extending into the left PA. If the right PA is the branch with the same axis as the main PA: (b) 1-patch extending into the left PA is not a suitable technique because of later risk of "kinking" which will lead to restenosis; (c) A 2-patch enlargement technique avoids the risk of "kinking" and will reduce the risk for later restenosis.

Statistical analysis
All statistical analyses were performed using computer software StatView version 4.5 (Abacus Concepts, Berkeley, CA). Student’s t test (one-sample paired test), Mann-Whitney, and Fisher’s exact test were employed to assess differences between groups for statistical significance, where appropriate. A probability level of p less than 0.05 was regarded as significant. The Kaplan-Meier product limit method was used for calculating reoperation free intervals for Groups A and B.

	Results

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Immediate postoperative results
The hospital mortality after complete correction of TOF was 1.4% (7 of 501 patients) compared with a hospital mortality of 25% (9 of 36) after palliative procedures. Following complete correction of TOF, the postoperative PA-RV gradient was significantly decreased compared with the preoperative value, 70.1 ± 15.2 versus 15.5 ± 9.6 mm Hg (ranging from 0 to 40 mm Hg), p < 0.001, while cardiac output increased from 3.92 ± 0.89 L/min to a postoperative value of 4.38 ± 0.65 (ranging from 2.9 to 5.4) L/min, p less than 0.0001.

Follow-up
Complete follow-up was achieved in 368 patients (73%) between 1 and 20 years after complete correction of TOF. Mean follow-up time was 9.6 ± 5.4 years. Patients lost for follow-up were referred for surgery from developing countries worldwide and follow-up correspondence was sometimes difficult.

During the follow-up, 11 patients died, 3.0% (11 of 368). Four died after reoperations (36%), 4 had sudden death, most likely due to asymptomatic arrhythmia, and 1 died from sepsis, 1 because of massive aortic insufficiency, and finally 1 patient succumbed in a road traffic accident. At the end of the follow-up, 328 patients (90%) were in New York Heart Association (NYHA) class I, 32 patients in NYHA class II, and 8 patients in NYHA class III. Ninety percent of all operated patients reached adult age. Systemic catheterization in 218 patients during follow-up revealed the presence of a mild PA-stenosis (gradient less than 25 mm Hg, diastolic murmur without hemodynamic importance) in 85 patients (39%). A moderate PA-stenosis (gradient 25 to 30 mm Hg, diastolic pulmonary pressure less than telediastolic right ventricular pressure) was observed in 17 patients (8%), while severe PA-stenosis (gradient greater than 50 mm Hg) was seen in 4 patients (2%). One hundred and twelve patients (51%) had no detectable PA insufficiency. Thirty-seven patients, 7.4% (37 of 501) required reoperation following complete correction of TOF and were separately analyzed below.

Analysis of 37 reoperations after complete correction of TOF
Age at reoperation was 9.1 ± 6.4 years (ranging from 0.5 to 29 years). The overall average time interval from the primary operation to the reoperation was 5.0 ± 5.9 years (ranging from 1 month to 25 years). Twenty-four percent (9 of 37) underwent reoperation within 1 year after the primary operation. Twenty patients (54%, 20 of 37) had their reoperation within the time interval 1 to 9 years following the primary operation, while 22% (8 of 37) had their reoperation more than 10 years after the primary repair.

The indications for reoperations are shown in Table 2. The majority of the reoperations, 68% (25 of 37), were performed because of RVOT stenosis or obstruction. One patient had a xenograft tube calcification that required a conduit replacement. The remaining patients presented with subvalvar lesions in 3, valvar lesions in another 3, while the majority of the patients (75%, 18 of 24) had supravalvar lesions at reoperation. Eight of those patients had pulmonary trunk stenotic lesions and 10 patients presented with more distal obstructive PA lesions, equally distributed between the left and right PA.

Five of the 7 patients who underwent reoperation due to severe pulmonary insufficiency had either absent (3 patients) or severely stenosed (2 patients) left pulmonary artery at the primary operation, and all of them were managed by RV-PA conduits (valved homografts) at the reoperation. The reoperation rates in relation to the type of surgical correction technique used at the primary repair of TOF in 241 patients with PA lesions are shown in Table 3.

During follow-up, yet another patient died of unknown cause 2 years after reoperation. The remaining patients were all in excellent condition without major residual hemodynamic lesions at the end of the follow-up.

Subgroup analysis
There was a marked difference in reoperation rate between two different repair techniques used for enlargement of the PA trunk and the PA bifurcation in patients with left PA stenosis or stenosis of the entire bifurcation at the primary correction. When a 1-patch enlargement technique extending into the left PA was used (Fig 2a) the reoperative rate was 33.3% (Group A, 16 of 48) which was significantly higher, p = 0.0264, compared with the reoperation rate observed when a 2-patch enlargement technique was employed (Group B), where the observed reoperation rate was only 4.3% (1 of 23). The latter technique consists of one longitudinal patch for the PA-trunk and a second transversal patch to achieve adequate enlargement of the PA bifurcation and the origin of the two pulmonary arteries (Fig 2c). The reason for reoperation for Group A was recurrent stenosis of the left PA or the entire bifurcation and, for Group B, recurrent stenosis of the entire bifurcation in the only reoperation case in this group. There was one death following reoperation for Group A, 6.3% (1 of 16) and none for Group B.

Mean follow-up for Group A was 12.9 ± 8.2 years and, for Group B, 5.6 ± 2.7 years. Preoperative and postoperative PA-RV gradients for Groups A and B are shown in Table 4, and actuarial freedom from reoperation for the 2 groups is presented in Figure 3.

View larger version (16K): [in this window] [in a new window]   Fig 3. Kaplan-Meier freedom of reoperation in patients undergoing correction of tetralogy of Fallot using 1-patch enlargement (Group A) and 2-patch enlargement (Group B) of the pulmonary artery bifurcation.

	Comment

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The incidence of reoperation after repair of TOF is reported to be between 5% and 14% [6–9, 12–15], which corresponds to 6.8% in the present series. Many reasons for restenosis of the RVOT can be identified such as restricted growth of the RVOT in patients with transannular patch enlargement, miscalculated sizing of the RVOT at the time of repair (early residual stenosis), angulation or stenosis of the left PA (congenital or after Blalock shunt), and compression/angulation of the PA bifurcation caused by RV hypertrophy or dilatation. Primary repair in infancy does not increase risk for reintervention on the RVOT [17]. It has been clearly demonstrated that early repair of TOF can yield excellent results, and initial palliation does not preclude early complete repair [18]. In a recent study by Knott-Craig and associates [17], primary complete repair was done in 68% and staged repair in 21%. Twenty-three percent of their patients had complex processes, including atresia in 53 of 68 patients [17]. In the present series, RVOT restenosis was the most common reason for reoperation, 65% (24 of 37 patients).

The most common location of recurrent RVOT is at the pulmonary bifurcation or at the origin of the pulmonary artery branches [14]. In our series, this location for restenosis was indeed the most common, 75% (18 of 24 patients). The concept that severe pulmonary regurgitation results in symptoms at longer-term follow-up is supported by Oechslin and coworkers’ [14] findings that 75% of the patients in their study required reconstruction of the RVOT, often for symptomatic pulmonary regurgitation. Pulmonary regurgitation is reported to be well tolerated through childhood and adolescence in the absence of important additional lesions [6, 19]. The ability of a patient to tolerate pulmonary valve regurgitation varies considerably, and recent studies by Gatzoulis, Norgaard, and their associates [20, 21] have demonstrated the protective effect of a poorly compliant right ventricle. Oechslin and colleagues [14] found that long-term complications of the RVOT are the most prevalent reasons for reoperation and were often associated with sustained ventricular tachycardia. When pulmonary valve insufficiency was the cause, the patient’s condition improved substantially with implantation of an orthotopically positioned prosthetic pulmonary valve, and the operative risk was minimal and perioperative morbidity was low [14]. Residual pulmonary insufficiency which required a reintervention occurred in 7 patients (18.9%), which again corresponds well with previous reports in the literature [8, 9]. Narrowing of the left pulmonary artery is a critical point in the treatment of TOF. This stenosis may be congenital, but can also be acquired as a complication during shunt procedure. An untreated left PA stenosis will result in pulmonary insufficiency and right ventricular enlargement as an eventual consequence. A vicious circle has started, because right ventricular enlargement will ultimately lead to compression and angulation of the PA bifurcation, which in its turn augments the severity of the PA stenosis. A left pulmonary artery stenosis should therefore, if possible, be corrected, and great attention should be directed towards this problem during shunt operations.

Due to the special anatomical features of the PA bifurcation, great attention should also be directed towards identifying the anatomical situation, particularly in patients with left PA stenosis, and the patch enlargement technique should be chosen according to the anatomy in each individual case in order to avoid early restenosis requiring reoperation.

The recurrence rate of RVOT at this level might indeed depend on the technique used to enlarge the pulmonary bifurcation. If an extended 1-patch enlargement technique is employed, particularly in patients with a stenosis of the origin of the left pulmonary artery which take off in a rather acute angle, the risk for restenosis is high (reoperation rate, 33.3%; Fig 2b). This is in bright contrast to a recurrence rate of 4.3% when instead a 2-patch enlargement technique was used, thus avoiding kinking and narrowing of the origin of the left PA. Our data on freedom from reintervention correspond to those reported by Knott-Craig and associates [17] where freedom from reintervention at 20 years was 68% ± 4% for TOF with pulmonary stenosis, but are significantly better than the 43% ± 16% for TOF with pulmonary atresia, reported by them, when we applied the 2-patch enlargement technique.

The method of choice for patients with restenosis of the RVOT, and certainly for patients with massive pulmonary valve insufficiency requiring reoperation, is implantation of a valved conduit [14, 16, 17, 20, 21]. Homografts are presently the best choice of conduit even though we recently experienced a case with massive calcifications in homograft 3 months postimplantation. The use of homograft is not a definite rule.

As closing remarks, we can conclude that 90% of the patients who have undergone complete repair of tetralogy of Fallot do reach adult age, and can live a normal life. However, ventricular arrhythmia constitutes the major threat to the patients on long term, because they occur more frequently with increasing age, can be asymptomatic, thus most likely be the main reason for late sudden death among TOF patients. Selection of patch enlargement technique at the primary complete correction of TOF is of importance, since when the appropriate technique is used, early restenosis requiring reoperation can significantly be diminished.

	References

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This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Bernard Faidutti Jan T. Christenson Afksendiyos Kalangos Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Faidutti, B. Articles by Kalangos, A. Search for Related Content PubMed PubMed Citation Articles by Faidutti, B. Articles by Kalangos, A. Related Collections Congenital - cyanotic