Fate of the aortic root after arterial switch operation

Objective: Concerns have been voiced about possible dilation and insufficie ncy of the neo-aortic valve after the arterial switch operation (ASO). Aims : To determine growth of the neo-aortic valve and the aortic anastomosis af ter ASO and the prevalence of insufficiency or stenosis. Patients and metho ds: Since 1977, 144 consecutive patients (pts) underwent ASO for transposit ion of the great arteries (TGA). Median follow-up was 8.65 years (0.1-22.5 years). Simple TGA was present in 97 pts and 47 had TGA with ventricular se ptal defect (VSD). Detailed echocardiography included measurements of aorti c diameter at four levels. The 608 measurements were compared with publishe d normal values. Results: The mean aortic valve z-score was 1.5, without si gnificant change with age (P = 0.75). Under 4 months, moan valve z-score wa s 0.63 +/- 2.20, between 5 and 12 months 2.56 +/- 2.30 (P < 0.0001). Gradua l grow th occurs thereafter. The aortic sinus follows an identical growth p attern. The aorta at the anastomosis, is initially smaller than normal (z-s core -0.64). After 3 months the z-score is 0.83, followed by continued grow th of 0.1 z-score per year. At the last visit, the aortic valve z-score was above 2 in 51 patients, between -2 and 2 in 72 and less than -2 in six pat ients, none of whom had a flow velocity above 2 m/s.,z-score of patient wit h VSD remained above those without VSD (P < 0.0001). Aortic insufficiency w as grade 2/4 in three patients, grade 3/4 in one and grade 4/4 in one. No p atient developed aortic stenosis. Conclusion: After ASO the neo-aortic valv e and sinus are larger than normal, representing the natural size differenc e in the prenatal situation and influence of associated cardiac malformatio ns. Ln the first year of life, rapid dilatation of the new aorta is observe d, followed by growth towards normalization of the valve and sinus size. St enosis at the anastomosis was not observed. Aortic dilatation by itself is rarely associated with significant insufficiency. (C) 2001 Elsevier Science B.V. All rights reserved.