Relation of Neoaortic Root Dilation and Aortic Insufficiency after Arterial Switch Operation

Park, Han Ki; Park, Young Hwan; Kim, Do Kyun; Hong, Yoo Sun; Lee, Jong Kyun; Choi, Jae Young; Cho, Bum Koo

Abstract

BACKGROUND: Arterial switch operation (ASO) has been the most effective surgical option for transposition of the great arteries. But, the inappropriate dilation of the neoaortic root has been reported and its effect on neoaortic valve function and growth of aorta has not been well documented. MATERIAL AND METHOD: Forty-eight patients who underwent cardiac catheterization during follow up after arterial switch operation were included in this study. Arterial switch operation was performed at a median age of 18 days (range 1~211 days). Preoperative cardiac catheterization was performed in 26 patients and postoperative catheterization was performed in all patients at 15.8+/-9.6 months after ASO. Postoperative ratios of the diameters of neoaortic annulus, root and aortic anastomosis against the descending aorta were compared to the size of preoperative pulmonary annular, root and sinotubular junction. Preoperative and operative parameters were analyzed for the risk factors of neoaortic insufficiency. RESULT: There were two clinically significant neoaortic insufficiencies (grade> or =II/IV) during follow up, one of which required aortic valve replacement. Another patient required reoperation due to aortic stenosis on the anastomosis site. Postoperatively, neoaortic annulus/DA ratio increased from 1.33+/-0.28 to 1.52+/-.033 (p=0.01) and neoaortic root/DA ratio increased form 2.02+/-0.40 to 2.56+/-0.38 (p<0.0001). However, the aortic anastomosis/DA ratio showed no statistically significant difference (p=0.06). There was no statistically significant correlation between the occurrence of neoaortic insufficiency and neoaortic annulus/DA ratio and neoaortic root/DA ratio. Non-neonatal repair (age>30 days) (p= 0.02), preopeative native pulmonaic valve stenosis (p=0.01), and bisuspid pulmonic valve (p=0.03) were the risk factors for neoaortic insufficiency in univariate risk factor analysis.
CONCLUSION
After ASO, aortic anastomosis site showed normal growth pattern proportional to the descending aorta, but neoaortic valve annulus and root were disproportionally dilated. Significant neoaortic valve insufficiency rarely developed after ASO and neoaortic annulus and root size do not correlate with the presence of postoperative neoarotic insufficiency. ASO after neonatal period, preoperative native pulmonary valve stenosis, and bicuspid native pulmonic valve are risk factors for the development of neoaortic insufficiency.