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Click here to read this article as a CME activity
a The Cardiac Centre, Hospital for Sick Children and the University of Toronto, Toronto, Ontario, Canada
b King Faisal Heart Institute, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
Accepted for publication May 21, 2007.
* Address correspondence to Dr Alsoufi, King Faisal Heart Institute (MBC 16), King Faisal Specialist Hospital and Research Centre, PO Box 3354, Riyadh, 11211, Saudi Arabia (Email: balsoufi{at}hotmail.com).
Presented at the Forty-third Annual Meeting of The Society of Thoracic Surgeons, San Diego, CA, Jan 29–31, 2007.
| Pediatric cardiac surgery:
The Annals of Thoracic Surgery CME Program is located online at http://cme.ctsnetjournals.org. To take the CME activity related to this article, you must have either an STS member or an individual non-member subscription to the journal.
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Abstract |
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Methods: Between 1982 and 2006, 306 consecutive patients underwent surgery for PAPVC; of these, 236 (77%) were children with a median age of 5.3 years (range, 0.47 to 18 years). Clinical and echocardiographic follow-up was obtained.
Results: PAPVC was right-sided in 214 patients (90%), left-sided in 17 (7%), and bilateral in 5 (2%). Anomalous veins were partial in 186 patients (79%) and involved the entire lung in 50 (21%). The most common type was right PAPVC into the superior vena cava in 175 (74%), with 87% associated with sinus-venosus atrial septal defect; followed by right PAPVC into the right atrium in 29 (12%), left PAPVC into the innominate vein in 22 (9%), and scimitar syndrome in 15 (6%). Repair strategy included intracardiac baffle in 203, pulmonary vein implantation in 22, and SVC division with reimplantation on the right atrial appendage in 14. There was no early or late mortality. Freedom from reoperation, vena cava obstruction, pulmonary vein obstruction, and pacemaker implantation at 15 years was 97%, 97.8%, 86%, and 99.1%, respectively. Pulmonary vein obstruction was significantly more common in patients with scimitar compared with others (22.4% versus 98.3%, p < 0.0001). Postoperative quantitative lung perfusion scans in 13 of 15 scimitar patients showed decreased right lung perfusion (mean, 22.5%).
Conclusions: Surgical treatment of PAPVC is associated with excellent outcomes and low time-related morbidity. However, management of children with scimitar syndrome is complicated by an exceptionally high incidence of postoperative pulmonary venous obstruction and abnormally diminished perfusion of the right lung.
Partial anomalous pulmonary venous connection (PAPVC) is characterized by the failure of one or more pulmonary veins to connect with the left atrium during fetal development. As an alternative, the anomalous pulmonary veins connect to the right atrium or to one or more of its venous tributaries [1–3]. PAPVC has been noted in 0.6% to 0.7% of autopsies but has been described less frequently in clinical series [1, 2].
Although surgical repair of PAPVC has been performed with excellent early outcomes for multiple decades, there have been numerous concerns about postoperative problems related to obstruction of the vena cava or pulmonary veins after baffle redirection of pulmonary venous blood into the left atrium or to anastomotic strictures after implantation of the anomalous pulmonary veins directly on the left atrium [4, 5]. An additional concern is related to postoperative dysrhythmias that have been reported in multiple series after surgical repair of PAPVC [4, 5]. Furthermore, scimitar syndrome is associated with lung hypoplasia, sequestration, and complex intracardiac anatomy that precludes effective baffling and thus influences long-term outcomes after surgical repair [6–9].
In this current series we report the outcomes of treatment strategies in the management of various types of PAPVC at our institution during the past 25 years and examine time-related morbidity associated with various operations used in their management.
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Patients and Methods |
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Partial Anomalous Pulmonary Venous Connection Characteristics
PAPVC is the anomaly in which some, but not all, of the pulmonary veins connect to the right atrium or to one or more of its venous tributaries [1–3, 10]. No concise classification system has been proposed for this disorder. We have adopted a classification that was modified from the one used in Kirklin and Barrett-Boyes [2] as follows:
Operative Technique
The surgical procedures varied according to the type of the anomalous connection. All operations have been previously illustrated by other groups.
In the right PAPVC-to-SVC type, two different strategies were used. The first was division of the SVC with reimplantation into the right atrium appendage, as described by Warden and colleagues [11] and others [12–14]. The SVC was cannulated close to the innominate vein. The SVC was divided above the highest anomalous pulmonary vein and the caudad stump was oversewn. The tip of the right atrial appendage was cut and anastomosed to the cephalad end of SVC. An autologous pericardial patch was then sutured to the margin of the sinus venosus defect, baffling the SVC orifice to direct the blood flow from the anomalous pulmonary veins into the left atrium.
The second strategy that was used more often, in 161 patients, was the intracardiac baffle, usually with a double-patch technique [15]. The SVC was cannulated high, close to the innominate vein. An incision was made on the lateral SVC wall just over the insertion of the anomalous pulmonary veins. This was extended in a cephalad manner to incorporate the junction of all anomalous pulmonary veins with the SVC and in a caudad manner into the right atrium while remaining at its lateral posterior wall to avoid the sinus node. The ASD was created or enlarged if needed. An autologous pericardial patch was used to baffle the blood from the orifices of the anomalous pulmonary veins into the left atrium through the ASD. The SVC incision was closed primarily on occasion but more commonly with an additional patch of autologous pericardium.
In the PAPVC–to–right atrium type, a single autologous pericardial patch was used to close the ASD and baffle the drainage of the pulmonary veins into the left atrium.
In the scimitar type, a long baffle of autologous pericardium was placed within the lumen of the IVC to channel the anomalous pulmonary vein effluent to the right atrium, then through an ASD into the left atrium. A period of circulatory arrest was often required to distinguish the pulmonary vein orifice from the hepatic veins that were close together. The IVC diameter was often augmented with a patch to prevent caval obstruction. In addition to intracardiac baffling, procedures such as control of aberrant aortopulmonary sources of blood flow and coarctation repair were often needed in scimitar patients.
Finally, in left PAPVC, the left atrial appendage tip was amputated, the vertical vein connecting the pulmonary and the innominate veins was divided, and the caudad end was implanted on the left atrial stump. This procedure was occasionally performed off cardiopulmonary bypass (CPB) with control obtained with vascular clamps; however, CPB was often required in cases associated with an ASD or when a bilateral PAPVC was present.
Since the introduction of transesophageal echocardiography (TEE) at our institution, evaluation of repair was done by intraoperative TEE to rule out residual shunts and caval or pulmonary venous obstruction.
Follow-Up
Late outcomes were determined from recent office visits at the Hospital for Sick Children, when available, or from correspondence with the patients’ outside cardiologists. Freedom from pulmonary venous or vena caval stenosis was determined by reviewing serial echocardiograms in addition to perfusion scans and angiograms for the scimitar patients. Mean follow-up was 10.6 ± 11.1 years.
Statistical Analysis
Data were analyzed with SAS 9 software (SAS Institute, Inc, Cary, NC) and presented as frequency, median with range, or mean ± standard deviation, as appropriate, with the number of nonmissing values indicated. Unrelated two-group comparisons were done with unpaired, two-tailed t tests for continuous variables and 
2 or Fisher exact tests for categoric data. Estimates for long-term survival or freedom from morbid events were made by the Kaplan-Meier method. Differences between survival curves were evaluated with the log-rank statistic.
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Results |
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TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionReferences |
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PAPVC were right-sided in 214 patients (90%), left-sided in 17 (7%), and bilateral in 5 (2%). Anomalous pulmonary veins were partial in 186 patients (79%) and involved the entire lung in 50 (21%).
The most common anomaly type was right PAPVC into SVC in 175 (74%); of those, 153 (87%) were associated with SV-ASD and the remaining 23 (13%) had an intact atrial septum. During the same study period, 172 patients were operated on for SV-ASD. Among those, PAPVC was reported to be present in 153 (89%) and absent in 19 (11%). Right PAPVC into the right atrium was the second most common type, in 29 (12%), followed by left PAPVC into innominate vein in 22 (9%), and scimitar syndrome in 15 (6%).
Repair strategy included intracardiac baffle in 203, direct pulmonary vein implantation in 23, and SVC division with reimplantation into right atrial appendage (Warden technique) in 14.
Freedom From Morbid Events
There was no early or late mortality in this series. Four reoperations occurred during the follow-up period. Two patients with PAPVC to SVC after intracardiac baffle had evidence of right pulmonary venous obstruction required reoperation and revision using the Warden technique. Two additional patients with scimitar syndrome required reoperation: 1 patient for patch augmentation of IVC stenosis caused by the intracardiac baffle, and the other for complete occlusion of the baffle. The latter patient underwent ASD closure, baffle removal, and had no perfusion of the right lung, which was left draining into the right atrium. Freedom from cardiac reoperations at 15 years was 97.8% ± 1.4%.
Only 1 patient required placement of a permanent pacemaker after surgical repair of scimitar syndrome. The 15-year freedom from pacemaker implantation for the entire cohort was 99.1% ± 0.8%. None of the patients with PAPVC to the SVC required a permanent pacemaker for bradyarrhythmias, although 1 patient with preoperative sick sinus syndrome underwent concomitant PAPVC surgery and placement of permanent epicardial pacemaker leads.
Late vena cava obstruction developed in 3 patients. The 15-year freedom from vena cava obstruction for the entire cohort was 97.8% ± 1.3%. IVC stenosis developed in 2 patients with scimitar syndrome, with 1 requiring reoperation. For the subset of patients with right PAPVC-to-SVC anomaly, SVC obstruction developed in 1 patient after SVC reimplantation into the right atrial appendage and was treated medically, whereas no significant obstruction of the SVC developed in the patients who underwent the intracardiac baffle repair.
Finally, pulmonary vein stenosis developed in 9 patients during the follow-up period. The 15-year freedom from pulmonary vein stenosis for the entire cohort was 86% ± 7.7%. Obstruction of the right superior pulmonary veins developed in 2 patients after baffle repair of right PAPVC to the SVC. Both required reoperation and revision of the repair, with SVC division and reimplantation into the right atrial appendage (conversion to Warden technique). Pulmonary vein stenosis developed in 7 other patients with scimitar syndrome, and 1 underwent reoperation and baffle removal.
Freedom from pulmonary venous obstruction was significantly lower for patients with scimitar syndrome compared with the nonscimitar patients: 22.4% versus 98.3% (log rank p < 0.0001; Fig 1).
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Diagnosis was confirmed by cardiac catheterization in 14 patients. At catheterization, the median calculated shunt fraction (Qp/Qs) was 2.5:1 (range, 0.9 to 3.7:1), the average mean pulmonary artery pressure was 28 mm Hg, and the mean oxygen saturation in the IVC was 86% versus 66% in the SVC.
All intracardiac repairs were done with the patient supported by CPB. Deep hypothermic circulatory arrest (mean 54 ± 22 minutes) was used in 8 children. The intracardiac repair consisted of baffling the anomalous venous channel with autologous pericardium through the right atrium and into the left atrium through an ASD, which had to be created surgically in 3 patients with an intact septum. Concomitant procedures were performed in 10 patients and included ligation of arterial collateral in 4, IVC patch augmentation in 4, and 1 patient each with coarctation repair, enlargement of right ventricular outflow tract, and patch enlargement of the right pulmonary artery.
During the follow-up period, postoperative cardiac catheterization was performed in 10 patients and quantitative perfusion scans in 13. Postoperative pulmonary venous stenosis was documented in 7 patients. Postoperative quantitative lung perfusion scans in 13 of 15 patients showed decreased right lung flow of a mean 22.5% ± 15.8% (range, 0% to 59%).
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TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionReferences |
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Right Partial Anomalous Pulmonary Venous Connection to Superior Vena Cava and Sinus Venosus–Atrial Septal Defect
The goal of surgical repair is to close the intraatrial communication and to create an unobstructed drainage of the right anomalous pulmonary veins to the left atrium and of the SVC to right atrium. Several techniques have been described to achieve those goals:
Although baffle repair of those defects has been historically associated with important surgical morbidity such as obstruction of the pulmonary vein orifices, SVC stenosis or obstruction, sinus node injury, and atrial bradyarrhythmias, more recent series have reported more favorable outcomes with minimal or no morbidity [3, 4, 13, 15–17].
Our current technique for the treatment of those patients is intracardiac baffle using autologous pericardial patch through a lateral right atrial and transcaval approach that is often supplemented with an additional patch to augment the SVC. We have avoided injury to the sinus node and therefore chronic bradyarrhythmia and tachyarrhythmias in all of our patients by limiting our incision at the SVC–right atrium junction to the lateral and posterior area. In addition, we have had no incidence of significant SVC stenosis or obstruction. After single-patch baffle earlier in our series, 2 patients had stenosis of the pulmonary veins pathway underneath the baffle. The use of the double-patch technique allows a more aggressive creation of a larger pathway to reroute the right anomalous pulmonary veins and potentially can avoid this problem without increasing the risk of significant SVC stenosis.
We have recently applied the limited lateral transcaval approach popularized by Nicholson in multiple adult patients with excellent early results. The Warden technique was used in our series in 14 patients and was associated with no pulmonary vein stenosis or arrhythmias; however, obstruction of the SVC–right atrium anastomosis site developed in 1 patient. Although we acknowledge the utility of this technique, especially in patients with high insertion site of the anomalous pulmonary veins into the SVC and those with pulmonary vein obstruction complicating the baffle repair, we rarely resort to this technique in our current practice owing to the very low incidence of surgical morbidity after double-patch baffle repair.
Right Partial Anomalous Pulmonary Venous Connection to Right Atrium
In our series, 29 patients had PAPVC into the right atrium in association with a large secundum ASD with deficient posterior limbus. Their preoperative echocardiograms showed anomalous drainage of the pulmonary veins. This type may represent anomalous drainage rather than true anomalous connection because the plane of division between the right and left atrium posteriorly is unclear; thus, the right pulmonary veins appear to have anomalous connection to the right atrium. Surgical treatment of those defects is therefore simple and consists of a single-patch closure of the defect that separates the left and right atrium posteriorly that allows the pulmonary veins to drain into the left atrium. This repair has been associated with no surgical morbidity.
Left Partial Anomalous Pulmonary Venous Connection
Left PAPVC draining into the right atrium through a vertical vein into the innominate vein is a relatively rare form of PAPVC and was found in 22 patients in our series. It was isolated left-sided in 17 patients or bilateral and associated with right PAPVC to the SVC in 5 patients. Twelve patients had associated ASD.
Our surgical technique involves direct implantation of the anomalous pulmonary vein into the left atrial appendage. Although this can be accomplished without the use of CPB; CPB was often needed for associated right-sided PAPVC or ASD closure. Despite concerns about stenosis of the pulmonary veins at the anastomosis site, we have had no late morbidity in our series. Although none of the follow-up echocardiograms showed any evidence of left pulmonary vein obstruction or stenosis, it is uncertain whether echocardiography can definitively rule out pulmonary vein stenosis. Additional studies such as magnetic resonance imaging (MRI), computed tomography (CT) scanning, or ventilation perfusion nuclear scans may be more sensitive and complementary in detecting pulmonary venous stenosis. All of our patients were asymptomatic during their last follow-up clinic visit.
Scimitar Syndrome
The children with scimitar syndrome are an interesting group of PAPVC patients. In addition to PAPVC into the IVC, which is the sine qua non of scimitar syndrome, these patients often have the associated anomalies of hypoplasia of the right lung, with dextroposition of the heart, and anomalous systemic arterial supply from the infradiaphragmatic aorta to a portion of the right lung [6–9, 18–23].
The age of initial presentation in our series spanned from early infancy to adulthood, and the symptoms depended on the severity of associated anomalies. When patients presented during infancy, the symptoms were usually severe and included failure to thrive, tachypnea, and congestive heart failure. Historically, the reported prognosis of those patients has been poor [6–9, 18–23]. When patients presented in later childhood, however, symptoms were frequently absent or minimal and limited to mild dyspnea or history of lung infections.
The additional associated anomalies contribute to the clinical presentation of the patients. Symptoms of congestive heart failure are usually related to a significant left-to-right shunt from PAPVC in addition to other intracardiac communications such as atrial or ventricular septal defects and the anomalous arterial supply to the right lung. Moreover, pulmonary hypertension is frequent, multifactorial, and is related to increased left-to-right shunt and thus pulmonary blood flow, pulmonary hypoplasia, stenosis of the anomalous pulmonary vein, and the presence of an anomalous high pressure systemic arterial supply to the right lung.
At our institution, failure to respond to medical treatment or the presence of a continuous, large left-to-right shunt (Qp/Qs > 2:1) were indications for surgical intervention. Although we, and others, have performed occlusion of the abnormal aortopulmonary collaterals with coil embolization, with temporizing effects, the results have not been consistent [9, 22, 23]. Preoperative perfusion scans were not widely available in our series. It is highly likely that right lung perfusion was diminished in those patients preoperatively.
Several surgical techniques for repair of scimitar syndrome have been described including (1) intracardiac patch baffling between the anomalous vein and the left atrium through the ASD [6, 7, 21], (2) direct implantation of the anomalous vein to the left atrium [8, 24, 25], and (3) division and implantation of the anomalous vein into the posterolateral wall of the right atrium with patch baffling into the left atrium [20].
We have mainly applied the first technique in our series, and our results have been disappointing, especially in younger children. Several anatomic factors may have contributed to our poor results, including original pulmonary vein orifice stenosis, the acute angle of almost 180° that the pulmonary venous blood must take as it traverses the baffle into the left atrium through the ASD, and potential shrinkage of the pericardial patch used as a baffle.
Alternative techniques have been described that may avoid some of the shortcomings of the intracardiac baffle strategy. Shumacker and Judd [20] reported good outcomes with division of the anomalous vein off the IVC and mobilization and implantation on the right atrial posterolateral wall. This technique may allow a shorter, more straightforward pathway and enlargement of stenotic vein orifices by incising them longitudinally. More recently Brown and colleagues [20] reported excellent intermediate results after direct implantation of the anomalous pulmonary vein on the left atrium in 9 patients with a technique done without CPB through a right thoracotomy; however, this technique is only applicable to patients without associated defects.
Although these alternative techniques may offer improved results, they are not without limitations. Direct implantation into the atrium may also be associated with obstruction of the pulmonary veins at the anastomosis site [20]. Huddleston and colleagues [9] have recommended a right pneumonectomy in those patients where the anomalous vein travels posterior to the right lung hilum.
Most patients with very limited or absent perfusion of the right lung complicating surgical repair in our series were asymptomatic on follow-up due to right lung hypoplasia and compensation of the left lung flow. Although some surgeons have recommended pneumonectomy to prevent pulmonary hypertension in failed repairs or nontransferable veins [9], this has not been needed postoperatively in our experience despite several patients with pulmonary venous obstruction.
Conclusion
Surgical treatment of PAPVC is generally associated with excellent early outcomes and low time-related morbidity. Nonetheless, children with scimitar syndrome continue to present a management challenge. Their picture is complicated by complex associated anomalies and lung hypoplasia. Intracardiac baffle technique has been associated with a high incidence of pulmonary vein stenosis, and alternative techniques may prove to be superior.
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Discussion |
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And the second question is, there’s two of your patients that you used intracardiac baffle. Can you tell us about those, would those patients have been better served with the Warden procedure?
DR ALSOUFI: Both patients initially had intracardiac baffle with a single patch and required a later revision with the Warden technique following development of pulmonary vein stenosis, and they did fine. In our series we have had no pulmonary vein stenosis in patients who had undergone the Warden procedure. Nonetheless, we have been in general very satisfied with the low incidence of pulmonary vein stenosis, especially with the double-patch technique, which continues to be our procedure of choice in the pediatrics population.
The Warden procedure has not been done at Sick Kids for many years, and I have not been personally involved in any single surgery. I don’t what kind of suturing technique was used in the past.
DR CARL L. BACKER (Chicago, IL): What material did you use for the patch? Was that autologous pericardium?
DR ALSOUFI: It is untreated autologous pericardium.
DR BACKER: The next question I have is regarding the left-sided anomalous vein. Were those all approached through a median sternotomy? Were some done through a left thoracotomy? Joe Dearani published a nice article on CTSNet where he described operating on these patients through a left thoracotomy without bypass. What was your approach for the left-sided anomalous connection?
DR ALSOUFI: All procedures were done through a sternotomy. Cardiopulmonary bypass was not needed in few patients with isolated left PAPVC. However, it was utilized in most of them because of the presence of bilateral PAPVC in 5 patients or concomitant atrial septal defects that required surgical closure.
DR BACKER: I know you looked at the incidence of the requirement for a pacemaker, which was very low. When we reviewed our patients with this type of anomaly, what we found was that they didn’t necessarily need pacemakers. However, with the two-patch technique, where the second patch was used to enlarge the SVC, we had a very high incidence of absence of normal sinus rhythm. These patients had a low atrial rhythm that did not increase normally with exercise. We felt that that was another reason to transition to the Warden technique. Did you look specifically at electrocardiogram (ECG) tracings for more subtle indications of sinus node dysfunction?
DR ALSOUFI: Our end point was any dysrhythmia or conduction anomaly that required a permanent pacemaker implantation. Late follow up ECGs and response to exercise were not widely available to assess for sinus node dysfunction.
DR FRANK A. PIGULA (Boston, MA): I just had one quick comment and question. I mean, you have really defined two separate populations: the scimitars and the nonscimitars. And in your scimitar group, you had 7 patients that had recurrent pulmonary vein stenosis but only 2 that required reoperation. So I guess my question is how you manage that, both initially and subsequently in the scimitar group?
DR ALSOUFI: All of them had cardiac cath reevaluation. Interestingly, none of them was found to have pulmonary hypertension, and none of them required pneumonectomy or lung transplantation. In fact, on the last follow-up, most of them were asymptomatic.
It may be that even though they have developed pulmonary vein stenosis, their right lungs remained viable and did not contribute to the later development of pulmonary hypertension and the fatal progressive disease that we saw in infants who did not receive surgery.
DR MARSHALL L. JACOBS (Philadelphia, PA): Did the scimitar group include any neonates or very young infants? Despite what you pointed out were less satisfactory results than the other lesions, if you had no mortality amongst the scimitars and there were some neonates or infants, then that is very commendable, surprisingly good results. And if not, was there a conscious decision not to operate on profoundly symptomatic neonates with scimitar?
DR ALSOUFI: In the current series, 6 patients had the infantile type of scimitar syndrome, with presentation less than 1 year old, and although all of them developed postoperative pulmonary stenosis, they are all alive. In a previous study that was published from Toronto, they compared infants with scimitar syndrome who had surgery and those who did not. There was a significant mortality, 5 out of 12, in infants who did not receive surgery and all because of pulmonary hypertension. So obviously, surgery was only offered to a selected group of infants, while those who were sicker were not offered surgical repair.
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