ABSTRACT
A 1-year-old baby boy underwent Mustard operation for simple transposition of the great arteries. He began to complain of fatigability with moderate cyanosis and polycytemia at the age of 23. Cardiac catheterization revealed baffle leaks at the superior vena cava (SVC) channel, but baffle stenosis was not diagnosed then. After the patch closure of the baffle leaks, he suffered from hypoxia and high SVC pressure. Baffle stenosis at the entry of the SVC channel into the functional right atrium was diagnosed by re-catheterization. Patch enlargement of the baffle stenosis was successfully performed. We must take it into consideration that baffle leaks following Mustard operation often coexist with baffle stenosis, requiring vigorous pre- and intra-operative exploration.