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© 2004 European Association of Cardio-Thoracic Surgery
Total anomalous pulmonary venous connection with dysmorphic pulmonary vein: a risk for postoperative pulmonary venous obstructionDepartment of Pediatric Cardiac Surgery, Sakakibara Heart Institute, 2-5-4 Yoyogi, Shibuya-Ku, Tokyo 151-0053, Japan
* Corresponding author. Tel.: +81-3-3375-3111; fax: +81-3-3375-9218 Received July 28, 2003; received in revised form April 21, 2004; accepted June 7, 2004
Pulmonary venous obstruction after repair of total anomalous pulmonary venous connection remains potential and understanding of its mechanisms is warranted. Morphology of the pulmonary vein was qualitatively analyzed in 48 consecutive patients undergoing repair of non-isomeric total anomalous pulmonary venous connection. Pulmonary venous drainage was supracardiac in 26, cardiac in 7, infracardiac in 13, and mixed in 2. Nine had dysmorphic pulmonary venous confluence or tributary veins (Group A). Four had excessive (  5) tributary veins with a hypoplastic confluence (Type 1 abnormality). In the other four cases, the vertical vein was atretic (Type 2 abnormality). In a case with cardiac type, pulmonary veins had stenosis at orifices (Type 3 abnormality). The rest ( Group B) had normal pulmonary vein. Eight patients (7 in Group A and 1 in Group B) developed postoperative pulmonary venous obstruction. Overall actuarial survival was 90.0% after 2.3 months up to 10 years. Actuarial freedom from pulmonary venous obstruction was 79.5% after 5.0 months up to 10 years. It was 22.2% at 1 year among Group A compared with 96.7% at 10 years among Group B  Morphological analysis of the pulmonary vein best predicted the incidence of postoperative pulmonary venous obstruction.
Key Words: Total anomalous pulmonary venous connection; Pulmonary venous obstruction; Venous disease; Reoperation; Mortality; Morbidity
Surgical outcome of total anomalous pulmonary venous connection (TAPVC) has improved owing to accumulated knowledge of the disease and advanced perioperative management [1–3]. In the current era when intravenous prostaglandin E1 is available, TAPVC is virtually the only true surgical emergency. Early detection of pulmonary venous obstruction (PVO) and prompt surgery have contributed to the improved surgical results. Postoperative PVO, however, is yet to be eradicated and frequently requires reoperation, which associates high mortality [4]. Mechanisms of PVO are generally classified into intrinsic (intimal hyperplasia of the pulmonary vein) and extrinsic (surgical obstruction). However, discrimination of these two mechanisms is often difficult. Hypoplastic confluence [2] or atresia of the connector vein [5,6] has been considered a risk for mortality and postoperative PVO. However, prevalence and surgical problems of these abnormalities have not been discussed in detail. The aim of this study was to investigate the prevalence of dysmorphic pulmonary vein in TAPVC patients and assess its impact on development of postoperative PVO.
Hospital and outpatient records of 48 consecutive cases of simple non-isomeric TAPVC undergoing total repair between October 1992 and March 2003 were reviewed. Patients with patent foramen ovale, atrial septal defect, or patent ductus arteriosus were included. There were 37 males and 11 females. The median age at repair was 14 (range 0–325) days and the mean body weight was 3.5±1.0 (range 2.1–7.2)kg. Thirty-one patients (64.6%) were newborns (  28 days after birth). Our policy was to perform surgery on an emergent basis whenever there was a sign of severe pulmonary congestion or hypoxia. Eighteen patients (37.5%) had been on mechanical ventilation before operation. Diagnosis was usually made by echocardiography alone (32 patients; 66.7%). In the remaining 16 patients, cardiac catheterization was done mainly to delineate pulmonary venous drainage, which was not clear by echocardiography. Drainage of pulmonary vein was supracardiac in 26 (Darling type [7] IA: 20, IB: 6), cardiac in 7 (IIA: 3, IIB: 4), infracardiac in 13, and mixed (IB+III) in 2. The morphology of the pulmonary vein was investigated qualitatively by preoperative echocardiogram, angiogram, operation record, or combination of them. Findings focused included the number of tributary veins, gross appearance of the confluence, presence of the stenosis within the tributary veins, and presence of diffuse stenosis or atresia of the connector (vertical) vein. Operation was done through a median sternotomy. A high flow (150 cm3/min), moderate hypothermic (30 °C) cardiopulmonary bypass was employed. Cardiac arrest was achieved by infusion of blood cardiplegic solution. In cases with supra- and infracardiac TAPVC, initial approach to the confluence was done from the right side of the heart (right-side approach). If exposure of the pulmonary vein was difficult in cases with supracardiac TAPVC, the pulmonary vein was exposed between the aorta and the superior vena cava (superior approach). A left atrial incision was made with a guidance of a right-angled clamp inserted through the atrial septal defect. The anastomosis between the pulmonary venous confluence and the left atrium was done in a side-to-side fashion using a running suture of 7-0 polydioxanone (PDS II®, Ethicon, Inc., Somerville, New Jersey). Patch augmentation of the confluence or the left atrium was done in neither of the cases. In cases with cardiac TAPVC, the orifice of the pulmonary vein confluence was detected through a right atrial incision. This orifice was rerouted to the atrial septal defect by cutting the primum atrial septum and the roof of the coronary sinus if the anatomy was type IA. Serial echocardiograms were taken routinely to detect PVO after operation. PVO was suspected if followings were present: (1) flow acceleration (>1.5 m/s) within the pulmonary venous channel, (2) narrowing of the confluence or tributary veins, and (3) elevated right ventricular pressure (>50% of the systemic pressure) as estimated by maximal flow velocity of the tricuspid regurgitation flow if existed. Patients were then brought forward for cardiac catheterization to confirm PVO. Preoperative variables included in the risk analysis for postoperative PVO were gender, age, body weight, preoperative mechanical ventilation, preoperative oxygen saturation, diagnoses (supracardiac, infracardiac, paracardiac and mixed), surgeon (A vs. others), and presence of dysmorphic pulmonary vein. Statview statistical software for Windows, version 4.5 (Abacus Concepts, Inc., Berkeley, CA) was used for data analysis. Values were expressed as mean±SD for continuous variables and median for discontinuous variables. Multivariable risk analysis for the incidence of postoperative PVO (binary outcome) was done using logistic regression model. Survival analysis was done using Kaplan–Meier product limited method with inter-group comparison using log-rank test.
The mean follow-up period was 27.9±30.2 (range 0.5–125.7) months. The pulmonary vein to the left atrial anastomosis was done by right-side approach in 32 cases and by superior approach in 10 cases. The intra-atrial rerouting was done in six cases with cardiac TAPVC. The mean cardiopulmonary bypass time and aortic cross clamp time were 80.7±22.4 and 42.0±11.2 min, respectively. The median intubation period after operation was 3 (range 0–135) days. There were four mortality cases at 0.1, 0.7, 2.0 and 2.3 months. The actuarial survival was 90.0% after 2.3 months up to 10 years. All of them had supracardiac TAPVC and progressive postoperative PVO. None of the mortality cases was related to acute pulmonary hypertensive crisis.
Other four patients required reoperation for postoperative PVO at 0.3, 2.0, 3.7 and 5.0 months. The actuarial freedom from postoperative PVO resulted in death or reoperation was 79.5% after 5.0 months up to 10 years. All patients who survived operation had good functional status at the time of latest follow-up. The actuarial freedom from PVO for cases that had been on mechanical ventilation was 80.2% at 10 years with an incidence of 3/18 (16.7%). It was 79.7% at 10 years for those without preoperative PVO (not mechanically ventilated) with an incidence of 5/30 (16.7%). The difference was not significant (
In nine patients, the pulmonary vein had significantly dysmorphism (Group A). The morphology of the pulmonary vein was considered normal if four pulmonary veins were draining into the well-formed confluence with patent connector (vertical) vein to the systemic circulation (
In two cases with supracardiac TAPVC and two cases with infracardiac TAPVC, tributary veins were draining asymmetrically without forming distinct pulmonary venous confluence (Hypoplastic confluence; Type 1 abnormality). All had excessive tributary veins (
According to logistic regression analysis, presence of dysmorphic pulmonary vein was the only risk factor delineated for postoperative PVO Actuarial freedom from postoperative PVO compared between those with and without dysmorphic pulmonary vein is shown on Fig. 2.
In two cases with mixed TAPVC, connectors were draining into both superior vena cava and hepatic vein. However, the pulmonary veins were draining symmetrically and there was a well-formed confluence. These patients did not develop PVO after operation.
The anatomical variation of TAPVC is diverse because of various potential connections of persistent splanchnic vein [8]. Obstruction of the pulmonary venous pathway may exist. The survival rate after repair of TAPVC has improved [1] and the reported early mortality is less than 10% in many centers [2,3]. However, reported incidences of PVO after repair are still about 5–10% [9,10]. Usually PVO is classified into that related to intimal hyperplasia of the pulmonary vein (intrinsic) and that related to surgical stricture (extrinsic) [11]. Postoperative PVO, if occurs, is associated with a high mortality [4]. In many instances, intimal hyperplasia follows extrinsic PVO and hence differentiation of these two mechanisms involved in the development of PVO is difficult. PVO before operation used to be delineated as a risk factor for mortality and postoperative PVO. Of recent, prompt indication of the operation has been advocated once the PVO is detected [12]. Together with an advancement of neonatal open-heart surgery, this risk factor has been neutralized [1]. Our data also showed that preoperative mechanical ventilation for pulmonary congestion/hypoxia (preoperative PVO) seems to be no more a risk of mortality and morbidity after repair.
The ideal morphology of the pulmonary vein includes four pulmonary veins draining symmetrically into the well-formed confluence with an unobstructed connector vein. In four cases (Type 1 abnormality), the pulmonary vein showed common anatomical features including (1) excessive (
Only one patient with a normal pulmonary vein required reoperation. There were obstructions of ipsilateral 2 pulmonary veins. Failure of adequate geometrical alignment might be involved. Extensive dissection of pulmonary veins might also help avoiding torsion or retraction of the pulmonary vein. Side-to-side anastomosis has been our routine practice except for cardiac TAPVC. However, considering the difficulty of this anastomosis in Type 1 abnormality, other modification like in situ pericardial repair [4] may offer better prognosis in the severe form. The major limitation to this study was a short follow-up period because of recent increase of surgical cases at our hospital. Risk analysis for postoperative PVO seemed relevant because all of them occurred within 5 months after repair. However, longer follow-up is mandatory to assure long-term patency of the pulmonary vein. In summary, we estimate that mechanisms of postoperative PVO involve (1) intrinsic obstruction, (2) anastomotic stricture, (3) torsion or retraction of pulmonary veins by inadequate geometrical alignment of the anastomosis, and (4) progression of preexisting stenosis of pulmonary veins. Genuine intrinsic PVO may accompany atresia of the connector vein with a thick pulmonary venous wall. Presence of preoperative respiratory compromise (PVO) or classical morphological typing did not predict postoperative mortality and morbidity associated with PVO. Instead, morphological analysis of the pulmonary vein best predicted the incidence of postoperative PVO. Accurate suture technique or certain modification may assure patency of the dysmorphic pulmonary vein associated with TAPVC.
ICVTS on-line discussion Author: Dr. Antonio Corno, CHUV, Department of Cardiovascular Surgery, 46 rue du Bugnon, Lausanne, CH-1011 Switzerland Date: 19-Jul-2004 Message: This is a very important contribution to an unsolved problem: how to prevent, and possibly reduce, the incidence of obstruction of pulmonary veins after the repair of total anomalous pulmonary venous connection (TAPVC). The reported observation constitute the first study addressed to the specific morphology of the pulmonary veins. Practical questions for the Authors, in order to take as much as possible advantage from their observations, are the following: • Do they consider these morphological characteristics as correlated or not with the type of hemodynamics? Is there any potential difference in patients with TAPVC with restricted pulmonary blood flow (apparently excluded in this study)? • Is there any other pre-operative tool that could be used to further investigate the morphological aspects of the anomalous veins, like MRI or multi-sliced CT? doi:10.1016/j.icvts.2004.06.004
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Abstract
1. Introduction
log-rank test). When classified morphologically into supracardiac, cardiac, and infracardiac TAPVC, incidences were 5/26 (19.2%), 1/7 (14.3%), and 2/13 (15.4%), respectively. The freedom from PVO at 10 years was 78.1, 75.0, and 79.1%, respectively. The 
-value of this difference was 0.96. 
Group B). 
log-rank test).
