Management of Congenital Aortic Stenosis by Catheter Techniques

Aortic valve stenosis constitutes 3-6% of congenital heart diseases with an incidence of 1-4 per 10,000 live births (Khalid et al, 2006). The prevalence of aortic stenosis at birth is 0.03% (Mahle et al, 2010). If left untreated, it can lead to considerable morbidity and mortality in neonates, infants, children and adults. Until three decades ago, the only treatment that could be offered to children with aortic stenosis was surgical valvotomy and valve replacement in adults. In 1983 balloon valvuloplasty was introduced as the initial palliation of choice for aortic valve stenosis in children and adolescents. Later in 1985, the procedure was extended to infants with critical aortic stenosis (Pass & Hellenbrand, 2002). Over the past 25 years advancement in technique and equipment has radically improved the safety and outcome of balloon valvuloplasty of aortic valve. Pathologically the stenosed aortic valve may be tricuspid (trileaflet), bicuspid or unicuspid (Fernandes et al, 2007). The latter is the result of failure of separation of the three leaflets with stenosis being centrally located. Rarely the annulus may be hypoplastic or secondary calcification may develop in children and adolescents. Bicuspid aortic valve is seen on 1-2% of general population (Bermudez, 2007). Natural history of bicuspid aortic valve is not well defined in children but has a spectrum ranging from critical stenosis to no stenosis or regurgitation (Han et al, 2007). After the fourth decade it can progress to aortic stenosis and regurgitation due to thickening, fibrosis and calcification, imparting rigidity to the fused cusps or due to infective endocarditis. There is associated aortopathy with bicuspid aortic valves, in adults as well as children, in which dilatation of ascending aorta is seen increasing the incidence of aortic dissection. Factors related to aortic dilatation are severity of aortic stenosis and regurgitation and jet angle of left ventricular ejection (Mahle et al, 2010).