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Scimitar Syndrome in a 3-Month-Old Infant

Updated: May 7, 2021

Howard Weber, MD, FSCAI; Khushboo Parikh, MD


Scimitar Syndrome is a rare congenital cardiac anomaly characterized by partial or complete anomalous pulmonary venous drainage of the right lung to the Inferior Vena Cava (IVC), either above or below the diaphragm.[1,2] It accounts for 3%–6% of all the partial anomalous pulmonary venous returns.[3] Scimitar Syndrome is frequently associated with hypoplasia of the right lung, dextroposition of the heart, hypoplasia or malformations of the right pulmonary artery, anomalous systemic supply of the lower lobe of the right lung from the abdominal aorta or its branches and pulmonary hypertension.[5]

Patients diagnosed before the first year of life were reported to have major associated cardiac defects and a worse prognosis.[2] Management of the scimitar vein with respect to timing and type of intervention remains controversial.[1]

We describe a case of 3-month-old infant with Scimitar Syndrome and pulmonary hypertension, diagnosed during the evaluation of a cardiac murmur in the setting of respiratory distress.

FIGURE 1 Enlarged cardiomediastinal silhouette. Increased interstitial edema and subsegmental airspace opacification throughout the right lung.

Case Presentation

A 3-month old previously healthy infant presented to an outside hospital with a cough, congestion and fussiness. She was noted to have saturations in the 80s in the Emergency Department. O2 supplementation was offered and she was admitted to the hospital. Chest X-ray demonstrated an enlarged cardiothoracic silhouette and increased interstitial edema (Figure 1). During the hospitalization the patient was noted to have a murmur warranting an echocardiogram. The study revealed a moderately-enlarged right atrium and right ventricle with suprasystemic right ventricular pressures. A moderate high secundum Atrial Septal Defect (ASD) with left-to-right shunting was noted. Only the left pulmonary veins were seen draining into the left atrium, and the right pulmonary veins were not well-defined. The decision was made to transfer the patient to a tertiary care center.

The following morning a cardiac CT scan was obtained to better delineate the underlying cardiac anatomy with special attention to the pulmonary veins. The CT scan showed complex right-partial anomalous pulmonary venous return, with two separate right pulmonary veins draining into IVC. An associated right aortopulmonary collateral arising from the celiac artery, and a mildly hypoplastic right pulmonary artery were noted. The scan also confirmed the echocardiographic finding of marked right atrial and ventricular enlargement. This confirmed the diagnosis of Scimitar Syndrome.

The patient was weaned off the oxygen and she remained stable on room air. Three days later the patient was taken to the catheterization lab. Angiograms performed in the catheterization lab revealed a 3.3 mm tortuous collateral arising from the abdominal aorta, which drained into the posterior aspect of the right lower lobe via two separate branches (Figures 2 and 3). The aortopulmonary collateral was coil embolized using a total of 3 Gianturco coils (one 4 mm diameter x 5 cm long, one 3 mm diameter x 4 cm long and one 2 mm diameter x 2.5 cm long). Repeat angiograms demonstrated complete occlusion of the aortopulmonary collateral.

Following a discussion with a cardiothoracic surgeon, and 3 days post-cardiac catherization, the patient underwent suture closures of the Atrial Septal Defect and tricuspid valve annuloplasty. Post-operative measured right ventricular pressures off cardiopulmonary bypass were 1/2 systemic.

Postoperative follow-up echocardiograms revealed moderately depressed RV function, moderate tricuspid regurgitation and systemic right ventricular pressures. The patient was placed on IV milrinone and supplemental oxygen with improvement of RV systolic function, although the pulmonary artery pressures remained at a systemic level. The patient was started on sildenafil and increased to 1 mg/kg q8hr; ultimately the pulmonary artery pressures decreased to 1/2 systemic prior to hospital discharge.

The patient was discharged home on 1 L O2 supplementation and sildenafil with plans to repair the scimitar vein at a later date.

To read the full article, please go to the March 2016 Issue of CCT.


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