**1. Introduction**

[9] Orihashi, K. Intraoperative imaging in aortic valve surgery as a safety net (Chapter 1). IN: Motomura N, ed. Aortic Valve Surgery. InTech Co., Croatia, (2011). , 3-18.

[10] Taniguchi, S, Noguchi, M, Onohara, D, et al. Aortic valve replacement with 17-mm St. Jude Medical Regent prosthetic valves for a small calcified aortic annulus in elder‐

[11] Coutinho, G. F, Correia, P. M, Paupério, G, et al. Aortic root enlargement does not increase the surgical risk and short-term patient outcome? Eur J Cardiothorac Surg

[12] Karimov, J. H, Cerillo, A. G, Solinas, M, et al. Stentless aortic valve implantation in heavily calcified aorta. J Cardiovasc Med (Hagerstown) (2009). , 10, 813-4.

[13] Di Matteo G Masala N, Swanevelder J, et al. Clinical outcome of a simplified techni‐ que for aortic valve replacement with stentless bioprostheses. J Heart Valve Dis

[14] Shin, H, Mori, M, Suzuki, R, et al. Apicoaortic valved conduit with an apical connec‐ tor for aortic stenosis with a calcified aorta. Gen Thorac Cardiovasc Surg (2009). , 57,

[15] Chahine, J. H, Rassi, I, & Jebara, V. Apico-aortic valved conduit as an alternative for aortic valve re-replacement in severe prosthesis-patient mismatch. Interact Cardio‐

[16] Crestanello, J. A, Zehr, K. J, Daly, R. C, et al. Is there a role for the left ventricle api‐ cal-aortic conduit for acquired aortic stenosis? J Heart Valve Dis (2004). , 13, 57-62.

[17] Chung, S, Park, P. W, Choi, M. S, et al. Surgical experience of ascending aorta and aortic valve replacement in patient with calcified aorta. Korean J Thorac Cardiovasc

[18] Iliopoulos, D. C, Deveja, A. R, Satratzemis, V, et al. Deep hypothermic arrest for aort‐ ic valve replacement in case of porcelain aorta. Asian Cardiovasc Thorac Ann

[19] Okamoto, H, Fujimoto, K, Tamenishi, A, et al. Aortic valve replacement in a heavily calcified "porcelain" aorta. Jpn J Thorac Cardiovasc Surg (2001). , 49, 453-6.

[20] Ooi, A, Iyenger, S, Langley, S. M, et al. Endovascular clamping of porcelain aorta in aortic valve surgery using Foley Catheter. Heart Lung Circ (2006). , 15, 194-6.

[21] Kudo, M, Misumi, T, & Koizumi, K. Aortotomy and endarterectomy of the ascending aorta for aortic valve replacement in a patient with porcelain aorta. Surg Today

[22] Orihashi, K, Kurosaki, T, & Sueda, T. Everted leaflet of a bovine pericardial aortic

valve. Interact Cardiovasc Thorac Surg (2010). , 10, 1059-60.

ly patients. Gen Thorac Cardiovasc Surg (2010). , 58, 506-10.

(2011). , 40, 441-7.

516 Calcific Aortic Valve Disease

(2009). , 18, 111-8.

vasc Thorac Surg (2009). , 9, 680-2.

Surg (2012). , 45, 24-9.

(2009). , 17, 415-6.

(2005). , 35, 1000-3.

467-70.

Congenital aortic stenosis (AS) is caused by abnormal morphological development of the aortic valve. [1, 2] Valvular abnormalities may be accompanied by supra- or subvalvular stenosis. The embryogenic process that forms aortic valves begins approxi‐ mately 31–32 days of gestation. Cavity formation in the basal portion of the truncus arteriosus is a key process in the development of the leaflet and sinus of Valsalva, which are important components of the aortic valve. Therefore, incomplete formation of the cavity causes various morphological abnormalities of the aortic valve, including bicuspid valve with or without commissural fusion, tricuspid valve with commissural fusion, monocuspid valve, and myxomatoid leaflet valve (dysplastic valve). The most frequent type of congenital AS is a bicuspid aortic valve, [3] accounting for approxi‐ mately 90% of AS cases.

Although the morphological features of the aortic valve are closely associated with the AS severity, the pathophysiology and resultant clinical manifestation of AS are funda‐ mentally determined by the severity of the stenosis (effective orifice area). In this sense, congenital AS in children is classified into 2 major types: severe AS that be‐ comes symptomatic and necessitates interventions during the neonatal period or early infancy and a milder form of AS with signs and/or symptoms that develop later in childhood.

In this chapter, we will outline the pathophysiology, clinical characteristics, and man‐ agement of congenital AS observed in children (from fetus to adolescence) for each type of AS mentioned above. We will also briefly discuss the differences in ventricular adaptation, which are strongly linked to the clinical manifestation of AS, to the in‐ creased afterload caused by AS between children and adults.

© 2013 Saiki and Senzaki; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
