Evaluation of surgical treatment of acquired and congenital aortic stenosis

Abstract

Summary The surgical treatment of aortic stenosis has not matched the success of the surgical treatment of mitral stenosis, and must be considered still in the developmental phase. Advances in classification and understanding of the various types of aortic stenosis and of the various stages in the life history of the disease have clarified the problems which must be solved by improvements in surgical methods. In adults with pure calcific aortic stenosis who are under age 60 and have not yet developed congestive heart failure, the closed transaortic or transventricular operation results in worthwhile relief of symptoms in two-thirds of cases, with an operative mortality which may be as low as 10 per cent. When heart failure has occurred the operative mortality is 30 per cent or more and only one in four has a good result from operation. In any event the procedure is palliative because of the formidable valve pathology which is almost always found. Open heart surgery has so far been attended by a high mortality and little evidence of better results, which may be possible only with prosthetic valve replacement. In carefully selected cases, good results may be obtained from combined operations for aortic and mitral stenosis. The clinical course and factors influencing the surgical result in most of these patients resemble those in pure mitral stenosis. The role of the associated aortic stenosis requires critical assessment by left heart eatheterization to determine the need for the double operation. Congenital aortic stenosis is of various types, all of which are best dealt with by open heart surgery in the opinion of most surgeons. These patients should be evaluated for surgery regardless of symptoms because of the risk of sudden death. Noncalcific valvular stenosis is a surgically favorable lesion, but serious regurgitation may be induced, even in direct vision operations. Subvalvular stenosis is often a formidable lesion which cannot be completely relieved, as is the rare supravalvular stenosis. The residual pressure gradient which often remains after surgical attack on the stenotic lesion is often functional, due to secondary muscular hypertrophy, and may be expected to regress with time. Rarely, usually in adults, subvalvular aortic stenosis is entirely functional, due to idiopathic muscular hypertrophy, and surgery has no place in the treatment of this condition. The selection of patients for operation for congenital aortic stenosis must be based on a careful assessment of all the circumstances, including the site and severity of the obstruction as revealed by left heart catheterization.