Copyright 2011 From the collection of Farzan Filsoufi, M.D.
In the early 1950's, the development of cardiopulmonary bypass became a reality after 20 years of research led by John Gibbons and his wife, Mary. John Gibbons performed the first successful cardiac operation on a human using heart-lung machine on May 6, 1953. The procedure was an atrial septal defect closure in an eighteen year old girl. The availability of extracorporeal circulation opened the era of open heart surgery with direct access to intracardiac structures including the mitral valve.
Lillehei performed the first mitral valve repair under direct vision for mitral regurgitation in 1956. Subsequently other repair techniques were described. Most these techniques, however, were palliative leading to over-narrowing of the mitral orifice and were associated with high failure rate. In addition, in many instances, valvular lesions were too advanced to be repairable and valve replacement would have been the only therapeutic option. In the late 1950's, intense research efforts were undertaken to develop a reliable prosthetic substitute to replace the damaged mitral valves. As the history showed only the efforts of very few, including those of Starr's, proved to be fruitful.
Albert Starr started his career as a young cardiothoracic surgeon at the University of Oregon Medical School in 1958. During the same period, he initiated his collaboration with Lowell Edwards who was a retired mechanical engineer on the design of a prosthetic valve in the mitral position.
The first implanted valves in the animal model were made of Silastic leaflets mounted in a rigid Teflon ring and surrounded by a Dacron cloth sewing margin. The results were disappointing because of a high rate of early thrombotic events and this design was abandoned. After designing and implanting several types of valves using various materials in laboratory, they decided to use a moving, free-floating poppet as in a ball valve.
As Starr recognized himself, ball valves were already available but their design was suboptimal leading to an extremely high early failure rate. Their first effort was to develop a mitral ball-valve prosthesis which would have the advantage of being independent of subvalvular attachment. After several months of intense research, Starr and Edwards made their own ball valve with new and improved materials. The case of the caged-ball valve was cast in one piece stainless steel or Stellite 21. The surface was then silicone coated. The knitted Teflon cloth fixation ring was attached by Teflon spreader rings and braided Teflon thread. The ball was made of Silastic. The first procedure was performed on August 25, 1960.
In their landmark article, Starr and Edwards reported eight cases of mitral valve replacement with their first generation of mechanical valve. Two patients died postoperatively and two had serious postoperative complications. At the time of the publication of their work, in 1961, most patients were doing well and were free of cardiac symptoms. For the first time, long-term survival could be obtained following mitral valve replacement.
In the discussion of their landmark paper, Starr and Edwards wrote:
"...the results presented in this report, in terms of extracorporeal accelerated fatigue testing and animal and human implantation, suggest that under certain circumstances the use of the ball-valve mitral prosthesis is justified. The indications for mitral replacement with this prosthesis are related to the operative findings and the comparative risks and advantages of replacement versus more conservative surgical management.However, the advantages of the prosthesis over plastic procedures on the mitral in terms of predictability of hemodynamic result must be balanced by the unknown long-term hazards involved in total dependence upon an intracardiac appliance. For this reason the only indication for mitral replacement in this series has been the operative findings of a hopelessly diseased valve not amendable to any reasonable plastic procedure in a patient with severe symptomatology (functional class III or IV) for whom prior permission for the use of the prosthesis has been obtained."
The pioneering work of Starr and Edwards opened the era of valve replacement surgery. Following this early experience, results improved steadily with a significant decrease in hospital mortality and mitral valve replacement became a routine procedure.
Starr and Edwards continued their research and Starr-Edwards ball valve went through several design and material modifications until the final product became available in 1964.
The design of the valve was also adapted to function as an aortic prosthesis. The cage was only constituted with three struts to align the aortic commissures. The sewing ring was extended downstream to be more suitable for the aortic annulus. The first clinical experience with the aortic valve prosthesis took place on September 1961.
Forty years after Cutler's initial work, surgeons had at their disposal a relatively simple, reproducible and reliable procedure to treat effectively their patients with valvular heart disease.
For his pioneering work which impacted the life of millions patients with valvular disease across the world, the Lasker foundation awarded Dr Albert Starr in 2007.