[Geometrical study on intra-arterial aortoinfundibuloplasty]

Newly-developed procedure for aortic annular enlargement was geometrically examined on its optimal annular augmentation. Valve prosthesis is accommodated by anterior annular split extending into aortopulmonary and infundibular septum and, eventually, protrudes into pulmonary valvular orifice in this procedure. Relationship between residual pulmonary valvular area (PVA) and aortic annular incremental radius (x) is given by: PVA = (r+x)2 [pi - 2 pi x/(r+x) + sin (2 pi x/(r+x))], where r is original aortic annular radius. Optimal aortic annular augmentation maximizing PVA and saving original PVA is 1.33 times and 1.70 times of original diameter respectively. Animal experiments employing six mongrel dogs demonstrated no significant increase of systolic peak pressure gradient in right ventricular outflow tract after the procedure standardized by this geometrical idea. Our procedure would bear radical enlargement of small aortic annulus.