Scimitar Syndrome

Scimitar Syndrome is a kind of Congenital Heart Defect (CHD) which is also referred to as Hypogenetic Lung Syndrome or Pulmonary Venolobar Syndrome. This kind of disease is very rare and mainly characterized by anomalous pulmonary venous drainage to the inferior venacava.^(1,2)

Scimitar Syndrome was first described in the year 1960 by Catherine Neil. Halasz et. al. first used the term ‘Scimitar’ in order to describe the radiographic appearance of an anomalous pulmonary vein.⁽³⁾ When it is characterized by the partial anomalous drainage it is called Partial Anomalous Pulmonary Venous Return (PAPVR), but if it is characterized by total anomalous drainage then it is called as Total Anomalous Pulmonary Venous Return (TAPVR). The syndrome which is mainly associated with Partial Anomalous Pulmonary Venous Return (PAPVR) is more commonly known as Scimitar Syndrome.⁽¹⁾

A lot of people suffering from scimitar syndrome remains asymptomatic and are able to lead a normal life. At times, it is very difficult to detect the symptoms of this disease since there are many patients who have Scimitar Syndrome yet were diagnosed only in their adolescence or adulthood as they remained asymptomatic or mildly symptomatic for several years of their life. The major characteristic feature of scimitar syndrome includes right pulmonary hypoplasia resulting in the moving of the heart to the right side (cardiac dextroposition), underdeveloped right pulmonary artery.^(1,3) At times, some patients may also have an anomalous systemic arterial blood supply to the hypoplastic lung from the descending aorta.⁽⁴⁾ In order to diagnose scimitar syndrome, several investigations need to be done over some period of years to detect the severity of the disease or associated abnormalities.

To diagnose Scimitar Syndrome, doctors mainly ask for the following tests:

• Transthoracic or Transesophageal echocardiography
• Angiography either CT angiography or MR Angiography.

The incidence of scimitar syndrome is found to be 1 to 3 per 1,00,000 live births having a 2:1 female predominance.^(5,6) However, the true incidence can be higher as many patients are asymptomatic. A large number of patients are incidentally diagnosed while doing tests for dyspnea, chronic fatigue, chest radiograph or when a person is evaluated for recurrent chest infections.^(7,8,9)

When it comes to treatment of scimitar syndrome, surgery should be considered in the presence of significant left to right shunting as well as pulmonary hypertension. While doing the surgery, the surgeon needs to create an interatrial baffle so that the pulmonary venous blood can return into the left atrium. However, there is another process that the surgeon can follow in treating scimitar syndrome and that is re-implanting the anomalous vein directly into the left atrium.⁽⁴⁾ In asymptomatic cases, the patient is usually observed and only if symptoms surface, it is managed through conservative measures. If anomalous arterial blood supply from the descending aorta to the hypoplastic right lung is confirmed, then embolization of the MAPCA (Major Aortopulmonary Collateral Artery) should be done.⁽²⁾

Scimitar Syndrome is a congenital pulmonary malformation of heart, lungs and blood vessels. This disease is rare having more predominance in female. People who are asymptomatic are able to live a normal life without much complication. When person suffering from scimitar syndrome has co-morbidities, the condition can be severe and the prognosis can be poor especially in case of infants.

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