Over a 13-year period, 20 infants and children underwent transsternal approach for repair of coarctation and associated cardiac defects. Fifteen patients (75%) were operated on in the last 6 years. Thirteen patients (group 1) had intracardiac shunts and 7 (group 2), intracardiac obstruction or valvular insufficiency. Group 1 had a mean age of 0.8 +/- 1.9 years versus 4 +/- 3 years for group 2 (p = 0.05). There were 12 patients (92%), 7 months old or less in group 1. Aortic arch hypoplasia was present in 6 patients in group 1. A large patent ductus arteriosus was present in 5 of these 6 patients versus no patent ductus arteriosus in patients without aortic arch hypoplasia (p = 0.006). The mean pulmonary blood flow to systemic blood flow ratio in group 1 was 3.8 +/- 2 and the mean right ventricular to left ventricular ratio, 0.8 +/- 0.2. The coarctation repair fell mostly into three types: side patch aortoplasty (8), ductal tissue excision and patch aortoplasty of the concavity of the aortic arch (6), and subclavian aortoplasty (4). There was one early death (5%) which was due to sepsis in a newborn. Another newborn who had subclavian aortoplasty needed a left carotid artery--descending aorta bypass conduit early because of aortic arch hypoplasia. All patients were followed to 12 years (mean follow-up, 4.3 +/- 3.5 years). There were no late deaths. Two patients had recurrent coarctation, 1 after an end-to-end repair and the other because of incomplete arch enlargement after a side patch aortoplasty.(ABSTRACT TRUNCATED AT 250 WORDS)