Scimitar vein with anomalous pulmonary venous return in an adult.

Abstract

An asymptomatic 40-year-old female was referred for preoperative clearance for gynecological surgery. The patient’s routine preoperative electrocardiogram (EKG) (Fig. 1) and chest x-ray (Fig. 2) were abnormal and for this reason the patient was referred for preoperative cardiac evaluation. Physical examination was significant for a prominent pulmonic component (P2) of the second heart sound (S2), with wide splitting but physiological respiratory variation. A grade 2 systolic murmur was heard along the left sternal border. History, reported from another institution, included an evaluation for a suspected atrial septal defect (ASD) based on an abnormal EKG and finding of an enlarged right heart by echocardiography. At that time, saline contrast studies via the right antecubital vein, with normal respirations and following release of the Valsalva maneuver, failed to demonstrate any evidence of a right to left shunt. Calculation of a pulmonicto-systemic flow ratio (Qp/Qs) was not performed. Based on the above, an echocardiogram was performed. The right heart was somewhat enlarged suggesting volume overload. Pulmonary artery pressures were normal (pulmonary artery systolic pressure <30 mmHg) as calculated by Doppler of the tricuspid regurgitant jet, and Qp/Qs calculated as 1.4:1. Subcostal imaging demonstrated drainage of an anomalous vessel (scimitar vein) into the inferior vena cava (IVC), near the IVC-RA junction and just above the diaphragm (Fig. 3). Computed tomography (CT) also demonstrated drainage of the scimitar vein near the IVC-RA junction and also a single small right pulmonary vein was noted to drain into the left atrium. The left pulmonary veins appeared normal (Fig. 4). Scimitar syndrome is a form of partial anomalous pulmonary venous connection (PAPVC), defined as a partial or total anomalous pulmonary venous return of the right lung to the IVC (just below or above the right hemidiaphragm) or less commonly the azygous system. The finding of a PAPVC is found in up to 0.7% of adult autopsies, with the Scimitar syndrome comprising up to 5% of these. Hypoplasia of the right lung with a dextroposition of the heart is often noted. Malformation of the right pulmonary artery, bronchial vessels, and an anomalous arterial blood supply to the right lung from the thoracic or abdominal aorta may be found. Up to 25% of patients with scimitar syndrome have associated defects, the most common being a secundum type ASD. Of patients found to have a secundum type ASD, about 10 percent will have a PAPVC, but not necessarily the scimitar syndrome. The infantile form may present as early as immediately after birth, having respiratory distress or other signs of heart failure, with right lung haziness on chest x-ray. Pulmonary hypertension with an infantile presentation is associated with a poor outcome. Other associated cardiovascular abnormalities are uniformly found in this form. The adult form is often asymptomatic, with diagnosis after the first year of age. Most lead a normal life without surgical correction. If, however, the Qp/Qs is more that 1.5–2: 1, patients may develop fatigue, exertional dyspnea, recurrent chest infection, and pulmonary hypertension. Use of the term “scimitar” was first coined by Halasz et al. describing the appearance of the anomalous right pulmonary vein by chest x-ray. The phrase “scimitar syndrome” was first used by Neill et al. The scimitar syndrome is a constellation of findings which includes the scimitar vein Address for correspondence and reprint requests: Edmund Kenneth Kerut, MD, Heart Clinic of Louisiana, 1111 Medical Center Blvd, Suite N613, Marrero, Louisiana 70072. Fax: 504-349-6621; E-mail: kenkerut@gmail.com