How Early Veno-Venous Malformation Can Jeopardize a Perfect Kawashima Repair: A Compilation of Two Cases and Review of Literature.

Systemic veno-venous malformation (VVM) often develops following a Kawashima operation (KO), a procedure that makes a connection between the superior vena cava (SVC) and the pulmonary artery (PA) in the setting of a blocked inferior vena cava (IVC), in the presence of complex cyanotic congenital heart disease (CCHD) of a single ventricle. This case report describes two 12- to 13-month-old female patients weighing 6 kg who underwent the Kawashima operation. We found that VVM could be identified using cineradiography, above and below the diaphragm, following a Kawashima operation. We noted a significant decline in systemic oxygen saturation beginning on postoperative day 9 in one patient, temporally associated with angiographic identification of systemic VVMs, while the second patient maintained stable room-air saturations throughout follow-up despite similar hepatic venous incorporation. These findings suggest that targeted radiographic evaluation for systemic VVMs may be useful in selected patients with early postoperative desaturation following the Kawashima operation, enabling timely risk stratification and surveillance.