Prosthetic Aortic Stenosis

Abstract

A cause of early death after aortic valve replacement with a caged-ball prosthesis is obstruction to left ventricular outflow because the prosthesis is too large for the aortic root. Of 68 patients dying within two months of aortic valve replacement, death in ten, each of whom had had intractable low cardiac output after operation, was attributed at necropsy to prosthetic aortic stenosis, despite the use of small sized (8A Starr-Edwards) prostheses in seven of them. The diameters of the aorta at the sinotubular junction, determined from the preoperative cineangiograms, in the seven patients with prosthetic stenosis were < 30 mm in all. Poppet clearances, defined as the differences between poppet and aortic root diameters, ranged from 4 to 12 mm (avg. 9). In contrast, the diameters of the aortas at the sinotubular junctions in eight control patients (unobstructed prosthetic aortic valves and early death from other causes) were > 30 in all but one, and the poppet clearances ranged from 12 to 19 mm (avg. 15). Thus, prosthetic aortic stenosis is likely to develop after aortic valve replacement with rigid-framed caged ball valves if the preoperative aortograms disclose aortic diameters at the sinotubular junctions to be < 30 mm. In such patients, either the aorta must be widened for a caged-ball prosthesis or a central flow valve must be used.