Thus, in addition to the dilation at the sinuses of Valsalva associ- ated with the Ross repair, dilation of the native ascending aorta above the sinotubular junction can also occur. Although patients with conotruncal abnormalities (TOF, dextrotransposition of the great arteries [d-TGA] after arte- pulmonary atresia with VSD, trun- cus arteriosus) commonly have aortic diameters of 40 mm to 50 mm, aortic complications are extremely rare (only Therefore, there is no strong justification for empiric prophylactic surgery in such patients based solely on aortic diameter. Watchful observation has often been recommended unless surgery is being undertaken for other indications.S4.2.4.2-15 However, there are rare patients who develop substantially greater aortic enlargement and for whom prophylactic surgery may have more of a role. Risk factor management such as control of hypertension is important. There are no RCTs evaluating the efficacy of medical therapy to reduce the rate of progression of aortic dilation or incidence of aortic dissection in this population. See Online Data Supplement 36 for referenced studies. 4.2.5. Supravalvular Aortic Stenosis Recommendations for Supravalvular Aortic Stenosis Referenced studies that support recommendations are summarized in Online Data Supplement 37. 