Twenty 1-month-old piglets were subjected to aortic transection and primary repair either with a posterior-running, anterior-interrupted nonabsorbable suture (group 1) or a circumferential continuous absorbable suture (group 2) technique. Mean piglet weight increased by 886% at six months and 1,184% at nine months. Aortic cross-sectional areas increased by 243% and 340%, respectively. Grossly visible, though minimal, stricture formation was noted in three pigs from group 1 and was associated with an overall 5.8% average anastomotic stricture at six months and 3.5% at nine months in group 1, compared with 0.2% and -0.1%, respectively, in group 2. Adhesion formation, fibrosis, and foreign-body reaction were common in group 1 but negligible in group 2. This corresponded to a mean wall thickness measured at nine months of 2.0 +/- 0.9 mm in group 1 and of 1.0 +/- 0.4 mm in group 2.