INTRODUCTION
Scimitar syndrome is a rare form of partial anomalous pulmonary venous return (PAPVR). PAPVR by itself is relatively uncommon and constitutes 0.5% to 1% of all congenital heart diseases[ 1 ] . The syndrome was first described in 1836, consisting of anomalous pulmonary venous drainage from the right lung to the inferior vena cava, in which the descending anomalous vein (mostly vertical) forms the shadow of curving soft tissue along the right cardiac border on chest radiography, which resembles the short curved Turkish sword or “scimitar”[ 2 ] .
The true incidence of Scimitar syndrome is unknown, since many of the patients are asymptomatic, the approximate incidence that has been reported is 1 to 3 per 100,000 live births[ 3 ] . There is often a constellation of findings associated with Scimitar syndrome , including hypoplasia of the right lung, possible pulmonary hypertension, dextroposition of the heart, and anomalous systemic arterial supply (ASAS) with or without pulmonary sequestration[ 4 ] .
We present an unusual case of Scimitar syndrome associated with a tracheoesophageal fistula (TEF) Vogt type IIIb as an example of successfully prolonged compensation of serious cardiac defect and precise follow-up management.
CASE PRESENTATION
A female (term) neonate was born via cesarean section. Fetal echocardiography was not performed, while obstetric ultrasound observations were without special remarks. The pregnancy had been complicated by maternal arterial hypertension. Immediately after birth, the infant presented breathing difficulties along with signs of choking and aspiration (foam on the mouth), suspicious of esophageal atresia, and was therefore transferred to our institution for further treatment and evaluation. On admission, the infant appeared vitally stable, spontaneously breathing with the support of up to 2 L of oxygen via nasal cannula. Esophageal atresia with distal TEF in the membranous portion of the middle to the lower third of the trachea has been confirmed. Ligation of the distal TEF and termino-terminal (T-T) anastomosis of esophageal parts was performed through a right-side incision. She recovered with minor complications.
Further examination revealed wet rales bilaterally as well as prominent and splitting second heart sound on the right side of the chest. A chest and abdominal X-ray showed a globally enlarged heart moved to the right (dextroposition), with a central position in the thorax and suspicious enlargement of the right atrium. The hypoplasia of the upper right lobe was also suspected. Dextrocardia, as well as heterotaxy syndrome, could be ruled out with high probability, because there are normally lobulated lungs with the normal position of the liver, spleen, and stomach. An echocardiogram demonstrated situs solitus in dextroposition, with a slightly enlarged right atrium and ventricle, concordant atrioventricular and ventriculoarterial connections and normal drainage of the left-sided pulmonary veins to the left atrium, without a clear definition of right-sided pulmonary veins drainage and without visible additional anomalies.
To clarify the remaining doubts, we additionally performed thoracic computed tomography angiography (CTA) to confirm the diagnosis of Scimitar syndrome . CTA showed dilatation of the right atrium, right ventricle, and main pulmonary artery (inner diameter 1.6 cm), with a single right pulmonary vein that had an anomalous connection to the right atrium by scimitar-like vein emptying into the dilated suprahepatic inferior vena cava, just distal to the inferior vena cava-right atrium junction (Figure 1A , Supplementary Figure 1, https://links.lww.com/CARDIOPLUS/A8 https://links.lww.com/CARDIOPLUS/A9 Figure 1B ). Repeated echocardiography demonstrated spontaneous closure of ductus arteriosus without indirect signs of pulmonary hypertension and no need for therapeutic intervention.
Figure 1.: Computed tomography angiographic presentation of the Scimitar syndrome with pulmonary sequestration. A , The entire right lung is drained by a single pulmonary vein (arrow), which has an anomalous inflow into the suprahepatic segment of the inferior vena cava (*); B , Lung sequestration: an anomalous arterial supply of the right lower pulmonary lobe by phrenic artery (arrow) which arrives from the systemic circulation.DA: right atrium.
A repeated barium esophagogram demonstrated no esophageal leakage with circular stenosis (inner diameter 2–3 mm) at the level of T-T anastomosis. The patient has been fed from the start via nasogastric tube, with gradually advancing meal portions. In the postoperative period, she had problems with vomiting and weight gain, so she had another endoscopic evaluation, without the need for dilatation. It was concluded that the cause of feeding problems was the uncoordinated swallowing and poorly developed structures of the hypopharynx, which increased the risk of food aspiration. The airway was finally secured by placing a permanent tracheostomy (Figure 2 ).
Figure 2.: Postoperative sagittal computed tomography image showing permanent tracheostomy (arrow).
Findings obtained by non-invasive diagnostic methods [X-ray, echogram (ECHO), computed tomography] were verified by cardiac catheterization and selective angiography. By injection of contrast into the trunk of the pulmonary artery and its recirculation through the right lung, the confluence of pulmonary veins was shown, which flows into the suprahepatic segment of the wide vena cava inferior (Figure 3A ), while the presentation of the left pulmonary veins appeared normal. The normal inflow of pulmonary veins from the left lung into the left atrium was shown after the selective injection of contrast into the left pulmonary artery (Figure 3B ). Direct application of contrast into the confluence of right pulmonary veins showed a presentation of the Scimitar syndrome in posterior-anterior (Figure 3C ) and lateral projection (Figure 3D ). A summary of described findings is presented in Figure 4 , which shows an obvious positional anomaly that is neither dextrocardia nor levocardia, but clockwise rotation of the heart (dextroposition or dextroversion). There is a normal inflow of the left pulmonary veins into the left heart and the right pulmonary veins into the vena cava inferior, and the gastric tube due to the postoperative esophageal stenosis can be seen.
Figure 3.: Selective angiography of Scimitar syndrome . A , Application of contrast into the trunk of the pulmonary artery (1 ) and inflow of the left pulmonary veins into the left atrium (2 ) with inflow of the right pulmonary veins into the vena cava inferior via a common confluence (arrow)-posterior-anterior projection; B , Application of contrast into the left pulmonary artery with normal presentation of the left pulmonary veins inflow into the left (arrow)-lateral projection; C , Direct contrast application into the confluence of the right pulmonary veins, which flow into the vena cava inferior, followed by visualization of the right atrium (posterior-anterior projection); D , Lateral projection of the Scimitar syndrome .
Figure 4.: Final angiographic reconstruction of the heart in a child with Scimitar syndrome , including dextroposition, lung sequestration, and tracheoesophageal fistula . The heart is in a dextroversion and clockwise rotation-from the vena cava inferior we entered into the right atrium which is located in front of and below the right ventricle. The right ventricle is mostly located on the right side (normally it is on the left). Contrast has been applied into the wide trunk of the pulmonary artery (at catheter tip) (1). After recirculation, we can see the left atrium (typical presentation of the left auricle) (2) and left ventricle, which is normally filled with blood from the left pulmonary veins (3). At the same time, a confluence of the right pulmonary veins from the right lung is shown, which flows into the vena cava inferior at its opening to the right atrium (4). Additionally, there is a gastric tube in the stomach (5) because of slight postoperative stenosis of esophageal anastomosis.
The final decision was to continue medical management of TEF, provide further follow-up and perform complete surgical repair of the PAPVR later at the most appropriate time. The patient was discharged in stable condition with a plan of close follow-up with a pediatric cardiologist and pediatric cardiothoracic surgeon for continuous evaluation and treatment of Scimitar syndrome after an excellent general condition has been achieved. The details of the patient’s clinical course and overall treatment are shown in Table 1 .
Time
Events
Diagnosis was made at birth-first clinical presentation
Delivery was completed by cesarean section (37 + 2 weeks of gestation, birth weight: 3,010 g, birth length 52 cm, Apgar score 10/10), shortly after delivery plenty of foam was noticed, which suggested possible esophageal atresia.
The first day of life
Chest X-ray showed dextrocardia without signs of heterotaxy, atelectasis of the right upper lobe of the lung, and was highly suggestive of esophageal atresia with a distal TEF.Scimitar syndrome ).
19th day of life
Esophagography revealed a circular stenosis of the esophagus at the anastomosis site (2 mm wide), with prestenotic dilatation (10 mm long), without signs of remaining fistula.
At the age of 2 months
Bronchoscopy showed significant tracheomalacia and laryngomalacia.Scimitar syndrome ).
3-month follow-up
Without recurrence of esophageal stenosis, closed TEF, adequate physical progress. Cardiopulmonary stable, without signs of pulmonary hypertension.
12-month follow-up
Cardiac catheterization and selective angiocardiography confirmed partial abnormal inflow of the right pulmonary veins into the RA, left-right shunt is >50%, but so far without signs of pulmonary hypertension.
CT: Computed tomography; RA: Right atrium; TEF: Tracheoesophageal fistula ; VCI: Inferior vena cava.
The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013) and approved by institutional ethics board (UHC Zagreb, Croatia, 2020). Written informed consent was obtained from the patients parents for publication of this case report and accompanying images. A copy of the written informed consent is available for review by the editorial office of this journal.
DISCUSSION
Scimitar syndrome has also been termed “hypogenetic lung syndrome” or “venolobar syndrome ” in the previous literature. Associated congenital cardiovascular anomalies are seen in 75% of neonates and 36% of children with Scimitar syndrome . These include atrial septum defect (ASD), ventricular septum defect (VSD), coarctation of aorta, abnormalities of aortic arch, and abnormal relationship of the pulmonary arteries and bronchi[ 5 ] . Common non-cardiovascular anomalies include horseshoe lungs, small right hemithorax with diaphragmatic eventration, vertebral anomalies, scoliosis, hepatic herniation, absent inferior vena cava, and meningomyelocele[ 6–9 ] .
Scimitar syndrome can be presented through a wide spectrum of clinical presentations. However, in infancy, it is very often presented with dyspnea and respiratory distress syndrome, due to pulmonary overcirculation, associated pulmonary sequestration or hypoplasia of the lungs, as well as the presence of pulmonary hypertension. A typical triad of dextroposition of the heart, right lung hypoplasia, and respiratory distress is highly suspicious for this specific syndrome[ 5 ] . To our knowledge, there are only a few described rare cases of Scimitar syndrome associated with TEF, but none of them with type IIIb (esophageal atresia with distal TEF), which is presented in our case report . The diagnosis of this particular Scimitar syndrome was made by echocardiography and CT thoracic angiography. Through continuous follow-up, we concluded that there were no signs of pulmonary hypertension despite pulmonary sequestration. A distal TEF (type IIIb) was successfully surgically occluded, which provided conditions for the formation of T-T anastomosis of esophagus. Postoperatively, esophageal stenosis was suspected, due to difficulties with the establishment of oral nutrition, but it was ruled out by endoscopic treatment.
It was concluded that feeding difficulties were a result of uncoordinated swallowing due to poorly developed structures of the hypopharynx, which resulted in frequent food reflux that was a real danger for aspiration problems. At the same time, the postoperative course was complicated by difficult separation from mechanical ventilation, due to tracheomalacia and laryngomalacia, so an endotracheal cannula was implanted. Consequently, the number of respiratory infections was reduced and oral feeding has been achieved, followed by a slow progression in body weight.
CONCLUSION
Finally, it was decided to delay the complete surgical repair of partial anomalous venous return until after the first year of life, when there will be more appropriate conditions, which is also a time when there is lower expected mortality and lower residual pulmonary venous obstruction.
According to the unusual presentation and course of our case, we would like to emphasize how important precise follow-up management and prolonged compensation of serious cardiac defects are for a prospective clinical outcome.
AUTHOR CONTRIBUTIONS
IN and DŠ wrote the manuscript and participated in collecting data. AM participated in collecting data. DB and MHP performed the imaging examination, DB also participated in collecting data. IM and MHP revised the manuscript and participated in the writing of the paper.
CONFLICTS OF INTEREST STATEMENT
The authors declare that they have no conflict of interest with regard to the content of this manuscript.
DATA SHARING STATEMENT
All data generated or analyzed during this study are included in this published article.
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