Size and Stiffness of the Pulmonary Autograft after the Ross Procedure in Children

Progressive dilatation of the pulmonary autograft is one of the greatest concerns after the Ross procedure. Increased stress in the arterial wall may cause changes in the elastic properties of the pulmonary autograft, and thus lead to pathological dilatation. The present study aimed to investigate the changes in the autograft diameter and stiffness during follow-up after the Ross procedure. A total of ten patients underwent the Ross procedure at our institution between 2003 and 2011. Echocardiography was used to measure the diameters of the pulmonary autograft at the level of the annulus, sinus of Valsalva, and sinotubular junction. The stiffness index was calculated from the angiographic data, and compared with that of 16 age-matched control children. The diameters of the pulmonary autograft increased throughout the follow-up period, particularly at the level of the sinus of Valsalva and at the sinotubular junction. The aortic root was stiffer in Ross patients compared with control children (7.9 +/- 1.8 vs. 3.9 +/- 0.7 immediately postoperatively, p<0.01; 10.1 +/- 2.8 vs. 4.2 +/- 1.4 at 5 years postoperatively, p<0.01). Although no significant relationship was found between the stiffness index and the autograft diameter, the stiffness index tended to increase over time. Dilatation of the pulmonary autograft was accompanied by progressive change in aortic stiffness. Longer follow-up is warranted to clarify the impact of this change in aortic stiffness on autograft failure.