A rare case of large ventricular septal defect with minimal pulmonary vascular obstructive changes in a 41-year-old woman.

We describe a case of large ventricular septal defect (VSD) with minimal obstructive changes in the small pulmonary arteries of a 41-year-old woman. Before cardiac catheterization, some laboratory findings led us to consider that surgical closure of the defect would not be possible. However, because hemodynamic examinations showed only mildly elevated pulmonary vascular resistance, we patch-closed the VSD successfully. The histology of lung specimens showed only minimal obstructive changes in the small pulmonary arteries. Considering the size of the VSD and the age at which we hemodynamically evaluated the patient, the mildness of the pulmonary vascular obstructive changes appeared to be atypical in the natural course of a VSD of this size.