Balloon arterioplasty of recurrent coarctation after the modified Norwood procedure in infants.

Coarctation of the reconstructed aorta after the modified Norwood procedure for hypoplastic left heart syndrome is a relatively common occurrence that can have significant adverse effects. From 1992-98, 65 infants with hypoplastic left heart syndrome or variants thereof underwent a modified Norwood procedure. Of the 50 survivors of Stage I palliation, 10 (20%) were subsequently diagnosed with clinically significant obstruction of the aortic arch at a median age of 5.1 months. Eight of these patients underwent coarctation balloon arterioplasty. All 8 patients underwent successful dilation of the coarctation, with a decrease in the pressure gradient from 43+/-20 to 4+/-5 mm Hg and an increase in aortic diameter at the site of obstruction from 3.5+/-0.5 to 7.0+/-1.0 mm (both P<0.001). There was also a significant increase in lower extremity systolic blood pressure. Although there was no immediate increase in cardiac output after dilation in most patients, ventricular function was improved in 3 patients within 24-48 hr of the procedure and in all but 2 at the most recent follow-up (median 2 years). Two patients developed bradycardia during wire placement that required cardiopulmonary resuscitation. Two others died suddenly during the follow-up period. All surviving patients have undergone subsequent palliative procedures; none have required repeat intervention for arch obstruction. We found a 20% incidence of coarctation in survivors of the modified Norwood procedure. Balloon arterioplasty is effective in relieving this obstruction, and should be carried out promptly upon diagnosis to minimize its deleterious effects on ventricular function. Balloon dilation, however, should be considered a high-risk procedure in these fragile infants, and special attention must be given to cardiovascular support.