Young adult who has gone from being acyanotic to now being cyanotic

CXR of Eisenmenger syndrome due to ventricular septal defect / VSD
CXR AP at 4 years of age (above) shows mild prominence of the pulmonary arteries bilaterally. CXR AP at 24 years of age (below) shows marked enlargement of the pulmonary arteries bilaterally with peripheral pruning of the pulmonary vasculature.

The diagnosis was Eisenmenger syndrome due to ventricular septal defect.