GROWTH OF THE AORTIC ANASTOMOSIS, ANNULUS, AND ROOT AFTER THE ARTERIAL SWITCH PROCEDURE PERFORMED IN INFANCY

Background. We investigated the size and growth potential of the neoaortic root and aortic anastomosis after the arterial switch operation (ASO) for D-transposition of the great arteries (D-TGA) performed in infants. Circumferential suture lines connecting the great arteries and extensive surgery on the arterial roots to transplant the coronary arteries are essential parts of the ASO. However, little is known about the growth of the aortic anastomosis, the neoaortic root, and the neoaortic annulus after the ASO performed in infancy. Methods and Results. Serial echocardiograms on 50 patients with D-TGA who underwent ASO in infancy at our institution were reviewed, and the size of the aortic anastomosis, the neoaortic root, and the neoaortic annulus were compared with similar structures in a group of 312 control subjects. Before surgery, the native pulmonary root (future neoaortic root) was 1.59 SD larger (P<.001) and the native pulmonary annulus (future neoaortic annulus) was 1.4 SD larger (P<.001) in infants with D-TGA than the aortic root and annulus of control patients. At a mean of 22 months (12 months to 6 1/2 years) after surgery, the diameter of the aorta at the anastomosis was 0.45 SD smaller than the ascending aorta of control subjects (P<.001). The neoaortic root was 2.9 SD larger (P<.001) and the neoaortic annulus was 1.6 SD larger (P<.001) than the comparable structures in the control population. Most important, growth of the aortic anastomosis was commensurate with somatic growth, but the dilation of the neoaortic root appeared to be progressive over time. The neoaortic root was significantly more dilated in patients with a history of pulmonary artery banding (P<.001) and in patients with neoaortic regurgitation (P<.001). The presence of a ventricular septal defect was not significantly related to postoperative neoaortic root size. Conclusions. This study underlines the importance of continued acquisition and examination of the data regarding the long-term outcome of the arterial switch operation performed in infancy.