The dawn of surgical treatment of aortic insufficiency

Before the development and introduction in the clinical practice of the heart-lung machine in 1953, to allow intracardiac procedures to be performed under cardiopulmonary bypass (CPB), certain cardiac operations could be accomplished only on a beating heart under mild hypothermia or with the use of cross-circulation, as utilized by Walton C. Lillehei to successfully repair even complex congenital heart malformations. In 1953, Hufnagel and Harvey reported the successful implantation of a ball valve prosthesis into the thoracic aorta. This historical operation was performed on September 11, 1952 at Georgetown University Hospital in Washington, DC, in a female patient with severe aortic valve insufficiency. This device, designed to replicate the mechanism of a liquor bottle stopper, produced almost one century ago, consisted in a tubular chamber, with an inlet and an outlet, containing a hollow ball to reduce its gravity; indeed, a pressure of just 5 mmHg was enough to move the poppet in a completely open or closed position. The whole device was molded from a single piece to obtain a smooth surface. Initially, the entire prosthesis was made of methyl methacrylate (Lucite); subsequently the ball was changed with one made by a hollow nylon core covered by silicone rubber to reduce prosthetic noise. As Hufnagel himself stated: “This valve was developed for the treatment of aortic insufficiency and to serve as a prototype to test the possibility that a valvular prosthesis would satisfactorily function within the cardiovascular system.” In those years the CPB machine was still unavailable while replacement of the ascending aorta had not yet been performed. Therefore, Hufnagel was forced to insert this device into the descending aorta and implanting a prosthesis in that location was certainly made possible by the demonstration that the thoracic aorta could be safely temporarily clamped, as occurred during the first landmark operations performed by Robert Gross to close a patent ductus arteriosus or repair an aortic coarctation.