Immediate and follow-up results of balloon angioplasty of postoperative recoarctation in infants and children. The purpose of this article is to present immediate and follow-up results of balloon angioplasty of aortic recoarctations following previous surgery in infants and children. During a 45-month period that ended in June 1989, nine infants and children, ages 6 months to 7 years, underwent balloon angioplasty of recoarctation with resultant reduction in peak-to-peak systolic pressure gradient from 52 +/- 20 mm Hg (mean +/- SD) to 16 +/- 8 mm Hg (p less than 0.001) and increase in coarctation segment size from 3.4 +/- 1.4 mm to 6.1 +/- 1.6 mm (p less than 0.01). None required surgical intervention. There were no significant complications. Follow-up catheterization (16 +/- 7 months) data in six children and follow-up clinical (17 +/- 6 months) data in all children were available for review. Both the residual coarctation pressure gradient (6 +/- 6 mm Hg) and coarctation segment size (8.2 +/- 2.4 mm) remain improved (p less than 0.001) when compared with pre-balloon angioplasty values and the pressure gradient fell further (p less than 0.01) when compared with that measured immediately after balloon angioplasty. None developed restenosis, although one child required surgical relief of severe narrowing of isthmus of the aortic arch. None developed aneurysms. On the basis of this experience and that reported in the literature and because of high morbidity and mortality rates associated with repeat surgery for postoperative recoarctation, we recommend balloon angioplasty as the procedure of choice for relief of postoperative recoarctation with significant hypertension. 