1.69%/patient-year in a mixed pediatric population.134,143 Freedom from pulmonary homograft replacements after the Ross procedure is 90% at 12-year follow-up,142 with a right ventricular outflow tract deterioration rate of 1.66%/patient-year.134 Overall, the risk of reoperation is approximately 10% at 10 years, either on the autograft or the right ventricular conduit.142 In young adult patients, the overall survival and freedom from reintervention were not significantly different following the Ross procedure compared with mechanical valve replacement at mean follow-up of 14 years.144 Aortic–Left Ventricular Tunnel Introduction and Anatomy This very rare congenital heart disease represents an abnormal connection between the ascending aorta and the left ventricle The tunnel originates in the aorta, in most cases just above the right coronary artery in the right coronary sinus of Valsalva The tunnel courses down along the base of the aortic valve toward the left ventricle and enters the left ventricle immediately below the right coronary leaflet of the aortic valve Rarely the tunnel may arise from the left coronary sinus or end in the right ventricle or left atrium A tunnel bypassing the valve can compromise the structural support of the right coronary sinus and result in aortic regurgitation Aneurysmal dilatation of the intracardiac tunnel can cause subpulmonary obstruction by displacing the infundibular septum anteriorly Rarely the coronary artery can arise from within the tunnel Externally, a bulge in the area of aortic root and the right ventricular infundibulum can be seen Two anatomic types have been described: either a slitlike opening with no aortic distortion or large oval opening at the aortic end with or without aortic valve distortion predisposing to development of intracardiac and/or extracardiac aneurysm.145 Pathophysiology, Clinical Features, and Investigations Half of the patients present in early infancy with congestive heart failure caused by severe volume load to the left ventricle Associated lesions such as aortic stenosis, aortic atresia, right ventricular outflow tract obstruction, and ventricular septal defect are rare but can modify the clinical presentation.146 The electrocardiogram demonstrates left ventricular hypertrophy, with or without repolarization abnormalities due to left ventricular strain or ischemia Echocardiogram and Doppler flow studies are highly reliable in estimating morphology, flow in the tunnel, and functional and morphometric parameters of the left ventricle (Fig 44.22) The presence of paravalvar regurgitation renders it difficult to evaluate the status of native aortic valve by echocardiogram Additional anatomic imaging with magnetic resonance imaging, computed tomography, or catheterization can be useful, in particular with identifying the coronary ostia in relationship to the tunnel FIG 44.22 Transthoracic echocardiographic images from a parasternal long and short axis show an aortic–left ventricular tunnel (arrow) Note the aortic regurgitation arising above the valvar leaflets AO, Aorta; LV, left ventricle; T, tunnel Management Aortic–left ventricular tunnels are primarily addressed surgically Symptomatic neonates and infants undergo surgical repair on an urgent or semiurgent basis