Growth changes in the thoracic aorta of the piglet following patch angioplasty

Patch repair of the thoracic aorta using prosthetic graft material in neonates and infants has been advocated, but long-term results have not confirmed that the residual aorta grows. In this study five piglets had portions of aortic tissue excised, ranging from 38% to 72% of the aortic wall. Each pig underwent patch angioplasty repair of the thoracic aorta with prosthetic graft material. Piglets achieved full growth at approximately six months. Aortic catheterization and contrast angiography were done in each animal before it was killed. Growth and histologic study of the aorta was documented at postmortem examination. There were no blood pressure gradients at rest or with isoproterenol hydrochloride (Isuprel)-epinephrine challenge in four of the five piglets. In one animal that underwent a 72% resection of the aortic circumference, a 20-mm gradient was present at rest. It was concluded that the thoracic aorta in piglets will grow adequately to allow patch grafting of up to 70% of the aortic circumference.