Technique of Coronary Button Transfer Has no Impact on Neoaortic Root Size in Simple Transposition

Abstract

We studied the effect of various coronary transfer techniques (CTT) on neo-aortic root size after an arterial switch operation (ASO) in simple transposition by excluding the impact of recognized predisposing factors. One hundred and seventy-eight patients with simple transposition were reviewed retrospectively (January 2004-December 2018) and grouped as Punch Hole (n=83/178), Nonpunch Hole (n=65/178; Trapdoor or Standard) and Mixed (n=30/178). Factors predicting the neo-aortic root z-scores- annulus, mid-sinus, and sinotubular junction (STJ) were analyzed by uni/multivariable linear regression. Follow-up was 6 years, Interquartile range (IQR) 3.4,10.6. Preoperative aortic (7.4 mm, IQR 6.9,8) and pulmonary annulus (7.5 mm, IQR 6.8,8.1) sizes were identical (P=0.831). The changes in preoperative, postoperative, and latest median z-scores for neo-aortic annulus (-0.2, IQR -1.2,0.9; 0.0, IQR -0.9,0.9; 0.9, IQR -0.4,2.6; P < 0.001), mid-sinus (1.1, IQR-0.1,2; 2.6, IQR 1.6,3.7; 2.9, IQR 1.8,4.3; P < 0.001) and STJ (-0.1, IQR -0.8,1.1; 2.1, IQR 0.7,3; 2.4, IQR 1,3.5; P < 0.001) were significant. On multivariate analysis, preoperative pulmonary annulus z-score predicted the latest neo-aortic annulus z-score [Beta estimate (BE)=0.32, 95% confidence interval (CI)=0.03,0.62; P=0.03] and STJ z-score (BE= 0.45, 95% CI= 0.20,0.70; P < 0.0001). CTT did not predict any of the latest neo-aortic z-scores (all P > 0.05). Mild plus neo-aortic regurgitation (neoAR) was not significantly different across CTT groups [punch hole 20% (n=15/74), mixed 37% (n=11/30), nonpunch hole 21% (n=13/62); Fisher-exact P=0.186], one patient required valve replacement for severe neoAR. The neo-aortic root enlarges significantly over time at all 3 levels following an ASO in simple transposition, however, this is not significantly influenced by the CTT utilized.