Risk Factors for Neo-Aortic Root Enlargement and Aortic Regurgitation Following Arterial Switch Operation

Abstract

The objectives of this study were to evaluate changes in dimension of the neo-aortic annulus, aortic root, and aortic anastomosis following arterial switch operation (ASO) and to identify risk factors for developing abnormal neo-aortic root enlargement and aortic regurgitation (AR). Prior studies report development of neo-aortic root dilatation and AR in a small subset of patients after ASO. Predisposing factors for neo-aortic root dilatation and development of moderate/severe AR are poorly understood. We performed a retrospective review of all patients with d-transposition of the great arteries (d-TGA) or double-outlet right ventricle with subpulmonary ventricular septal defect (VSD) who underwent ASO from May 1986 to January 2001. Serial echocardiograms were reviewed to measure neo-aortic annulus, root, and anastomosis diameter (z scores) and to determine progression of AR. Potential risk factors were assessed for developing neo-aortic root enlargement and AR. There were 119 patients (44 female and 75 male): 73 patients had simple d-TGA, 36 had d-TGA with ventricular septal defect, and 10 had a Taussig-Bing heart. The median duration of follow-up was 65 months (range, 12-180). The median neo-aortic root (z = 0.55+/-2.2; p < 0.01) and aortic annulus dimensions (z = 1.57+/-1.75; p < 0.01) were significantly increased over the study period. Aortic anastomosis diameter correlated with growth of the ascending aorta (z = 0.55+/-1.24). Development of severe neo-aortic root enlargement was associated with prior pulmonary artery (PA) banding (p < 0.01), the presence of a VSD (p = 0.03), and Taussig-Bing anatomy (p < 0.01) but was independent of coronary arterial anatomy, coronary arterial transfer technique, or associated lesions (p > 0.05). At latest follow-up, there was no or trivial AR in 88 patients, mild AR in 29 patients, and moderate to severe AR in 3 patients. Risk factors for developing mild or worse AR included severe or rapid neo-aortic root dilatation (p < 0.01). Only 3 patients required surgical intervention for AR. Despite the significant prevalence of neo-aortic root enlargement at intermediate follow-up after ASO, there is a low incidence of significant AR. Prior PA banding, the presence of VSD, and Taussig-Bing anatomy are risk factors for severe root enlargement. Surgical intervention for AR was rare (2%), however, serial surveillance of such patients is vital to monitor for neo-aortic root enlargement and potential aortic valve dysfunction.

Implications of Early Aortic Stiffening in Patients With Transposition of the Great Arteries After Arterial Switch Operation

“…Aortic root enlargement after ASO has previously been reported from our group 4 and by other echocardiographic studies. 19,20 A CMR study by Grotenhuis et al 8 in 15 TGA patients also revealed significantly increased aortic root diameters. Furthermore, they showed that patients with AR had even larger aortic root diameters.…”

Pathophysiology of Congenital Heart Disease in the Adult

“…Progressive dilatation and valvar insufficiency of the reconstructed aortic root may be problematic and may necessitate valve replacement later in life. 35 Branch pulmonary artery stenosis may result from pulling the main pulmonary artery trunk forward to anastomose it to the former aortic root. 36 This may be a clinically important afterload for the RV or may significantly redistribute pulmonary blood flow from 1 lung to the other if the degree of obstruction of the branches is unequal.…”

Monitoring the Patient with Transposition of the Great Arteries: Arterial Switch Versus Atrial Switch

“…Neoaortic regurgitation is a concern, and is present to some degree in the majority of adult patients [19••]. In young adults with ASO, an up to 3% incidence of moderate-severe neoaortic regurgitation has been reported [62,63]. Neoaortic regurgitation is related to root dilatation and to the need for pulmonary artery banding prior to definitive repair or repair of an associated VSD [61,62,64,65].…”