Pulmonary-to-systemic flow ratio: lung cancer with partial anomalous pulmonary venous return.

We investigated the usefulness of pulmonary-to-systemic flow ratio as an indicator for vascular reconstruction for pulmonary resection in two patients with primary lung cancer complicated by partial anomalous pulmonary venous return. The lung cancer and partial anomalous pulmonary venous return were in different lobes; therefore, intraoperative pulmonary-to-systemic flow ratio was measured. In one case, the pulmonary-to-systemic flow ratio was 1.06, and surgical repair was deemed unnecessary. In the other case, the pulmonary-to-systemic flow ratio was 2.20; because of the high risk of postoperative right heart failure, we performed pulmonary resection and partial anomalous pulmonary venous return repair. The patients were discharged without postoperative heart failure or cardiovascular events. With the growing use of three-dimensional computed tomography and incidental detection of partial anomalous pulmonary venous return, pulmonary-to-systemic flow ratio is useful to determine the necessity of vascular reconstruction in addition to pulmonary resection.