A Case of functional mitral stenosis after intraatrial rerouting of left superior vena cava draining into the left atrium

Abstract

Left superior vena cava (LSVC) draining into the left atrium (LA) may result in right-to-left shunt, potentially causing cyanosis. We report a 9-year-old boy with functional mitral stenosis after correcting the LSVC draining into the LA. The patient underwent intraatrial rerouting using an autologous pericardial baffle together with intracardiac repair of the double outlet right ventricle at the age of 1 year. We confirmed that the intraatrial baffle was preventing the mitral inflow soon after this intervention. Functional mitral stenosis had increased to the moderate grade eight years after the surgery. Moreover, the intraatrial route was occluded, and blood from the upper body flowed to the inferior vena cava through the markedly dilated hemiazygos vein. We established cardiopulmonary bypass and cardiac arrest and observed the occluded ostium of the intraatrial rerouting of the LSVC through right atriotomy. The mitral valve was concealed by the rerouting baffle. We completely resected these tissues and had no mitral injury or regurgitation. The postoperative recovery of the patient was uneventful. Based on this result, the surgical strategy for this patient group, such as rerouting pathways and the material of the baffle, must be carefully reconsidered, according to the anatomy of each case. J. Med. Invest. 73 : 537-541, August, 2026