Coronary artery pattern and outcome of arterial switch operation for transposition of the great arteries. A successful outcome of an arterial switch operation (ASO) for dextro-transposition of the great arteries (D-TGA) depends in large part on the transfer of the coronary arteries to the neoaorta without distortion or narrowing. However, the origins and distribution of the coronary arteries are quite variable in D-TGA; therefore, the entire experience with ASO at the Children's Hospital in Boston was reviewed. From 1983 through November 1989, 314 patients underwent surgery for D-TGA with the intent to perform an ASO. An ASO was actually performed in 290 patients, and 20 patients died, with 12 deaths (4.2%) clearly related to problems with the coronary arteries (CA deaths). The ASO was aborted to a Senning operation in 24 patients (7.6%), primarily due to coronary anatomy. Eight coronary patterns were identified and related to the outcome of the ASO. In 182 patients with the "usual" coronary pattern for D-TGA (i.e., anterior descending and circumflex arteries from the left sinus and right coronary artery from the right sinus), five CA deaths occurred, and two patients had Senning operations. Sixty-seven patients had right coronary and circumflex arteries from the right sinus and anterior descending arteries from the left sinus. Three CA deaths occurred, and one patient had a Senning operation. Single right coronary artery was found in 14; 12 had ASOs with three CA deaths (25%); and two had Senning operations. One late death was due to diffuse narrowing of the single right coronary artery. Single left coronary artery occurred in 11 patients, and seven had ASO with no early but one late "sudden" death, whereas four had Senning operations. 