Usefulness of open lung biopsy for corrective surgery on incomplete atrioventricular septal defect associated with severe pulmonary hypertension and right to left shunting

In congenital heart defects, it is sometimes difficult to decide the operative indication in patients, who has severe pulmonary hypertension (PH) and right to left shunting, from clinical symptoms and cardiac catheterization. We here report a case of incomplete atrioventricular septal defect. The patient is 9 months old with the Down's syndrome. The cardiac catheterization showed severe PH and right to left shunting. Preoperative mean pulmonary artery pressure was 75 mmHg, pulmonary systemic pressure to systemic pressure ratio (PP/PS) was 1.17, pulmonary systemic flow to systemic flow ratio (QP/QS) was 0.79, pulmonary systemic resistance to systemic resistance ratio (RP/RS) was 1.54 and pulmonary vascular resistance (PVR) was 9.6 woodunits.m2. These data suggested that the irreversible pulmonary vascular disease was present. However the PVR decreased from 9.6 to 3.6 woodunits.m2 after inspiration of 100% oxygen. We therefore performed open lung biopsy for further evaluation of the pulmonary vascular bed. The pathological findings obtained at lung biopsy indicated that there was no irreversible pulmonary vascular disease. This case was diagnosed suitable for a corrective surgery. Total repair was performed and the subsequent clinical course was satisfactory. We thus suggest that the open lung biopsy is useful to decide the surgical indication when it is difficult to determine an operative indication from hemodynamic measurement alone.