[Association of lung volume with shunt size in Starnes' procedure in neonates with severe Ebstein's anomaly]

Our modification of Starnes' procedure reduces right ventricular volume using only "suture plication" to improve surgical outcomes. However, shunt size in the procedure varies widely between patients. As this may be related to small lung volume, we estimated lung volume in each patient using computed tomography (CT).Since 2007, we have performed Starnes' procedure in 4 patients. Preoperative cardiothoracic ratio was 89±4.5%. Age and body weight at operation were 4.3±2.6 days and 2.6±0.2 kg, respectively. Anatomic slices 3 mm thick were acquired in transverse planes by CT. Total lung volume was calculated by accumulating those slices. Total lung volume and lung volume/body weight were 97.2±34.1 ml, 36.8±11.5 ml/kg, respectively. In one patient, a 3 mm prosthetic graft was needed to place a clip to regulate blood flow. Another patient required an additional shunt. The patient with the smallest lung volume required treatment with an extracorporeal lung-assistance device. Chest X-rays of neonates with severe Ebstein's anomaly usually show a "wall-to-wall" heart. However, lung volume varies widely between patients. Estimation of lung volume using CT is useful. In patients with smaller lung volume, a larger shunt than usual may be required to obtain the necessary pulmonary blood flow.