Ross Procedure Sections: Introduction | History | Anatomy | Pros & Cons | Patient Selection | Technique | Results | Pediatric Ross

History

The challenge to provide a suitable replacement for diseased human heart valve has been an ongoing process. Although a major forward advance was made with the development of man-made or artificial valves, there were still remaining problems, such as:

• Failure of artificial heart valves to grow in concert with the growing child.
• Lifelong risk of thromboembolism (clotting on the valve leading to stroke or other sequelae)
• Lifelong risk of valve thrombosis (clots which froze the mechanical leaflets)
• Requirement for lifelong blood thinning agents (i.e. Coumadin)
• Complications of anticoagulation (i.e. spontaneous bleeding)
• Audible noise when the valve closes (clicking sound)
• Risk of late infection (prosthetic endocarditis)

Intrepid surgeons in the early days of valve surgery experimented with human cadaver valves (so called homografts or allografts). However, there were problems with sizing and suturing cadaver heart valves, along with the expected problems of procurement and long term storage. In addition, these valves were still not native tissue from the same patient, but actually transplanted tissue obtained after the donors death. Most methods of preservation and long-term storage rendered all the cellular elements non-viable. Thus even homograft (cadaver) valves suffered from unique problems, such as structural deterioration, difficult implant surgery, and occasional size mismatching.

In the struggle to design the ideal heart valve, it became apparent to some surgeons that no replacement valve could provide a design as suited for the job as a normal semilunar 3-leaflet heart valve itself. Thus the road to pulmonary autografting was begun by Mr. Donald Ross of London, England. After more than 3 decades of development, the procedure he pioneered has now been shown to provide the closest approximation to an ideal aortic valve replacement as possible. All of the aortic valve reconstruction is done with native tissue transplanted from the patients own pulmonary valve. This operation, in its current modification, provides the best hemodynamic and functional result, nearly identical to a natural aortic valve.

The heart-lung machine was invented in 1954 by Dr. Gibbon of Philadelphia but was not readily available to other centers until the early 1960s. This device was the single major advance necessary before surgeons could safely enter the heart and replace or repair diseased cardiac structures. Initially, the heart-lung machine was only used to facilitate the repair of congenital malformations of the heart. However, surgeons were eager to apply this new technology to repair heart valves damaged by rheumatic fever in patients of all ages. After the invention of the heart-lung machine, what was needed was a suitable replacement for the diseased heart valve. In 1961, the first clinically successful replacement for the human mitral valve was implanted by Albert Starr, M.D. of Portland, Oregon. In conjunction with an engineer named Lowell Edwards, a functioning heart valve made from a steel cage enclosing a silicone rubber ball and was first used to replace the human mitral valve diseased by rheumatic fever. Although the mortality rate for these initial operations was nearly 50%, the Starr-Edwards valve proved to the medical and surgical community that it was feasible to replace a human heart valve with a man-made device and achieve both survival and relief of symptoms.

Unfortunately, both the heart-lung machine and the replacement valves available at that time were crude and less than ideal. A Starr-Edwards valve was certainly better than dying from end-stage mitral disease, but patients implanted with this device suffered from clotting on the valves, stroke, noise, and ingrowth of healing tissue (pannus) which eventually obstructed the valve orifice.

Demonstrating that the human mitral valve could be replaced quickly lead to similar successes with diseased aortic valves. Anatomically, the aortic valve is the gate which protects the heart chamber from receiving back the blood that after it just pumped. Without the aortic valve, blood would leave the heart, but just wash right back in, making the circulation ineffective. There are many common conditions which destroy the aortic valve, including rheumatic fever, infection (also known as endocarditis), and degenerative processes. In addition, one of the more common congenital defects of the heart is a 2 leaflet (bicuspid) aortic valve. Many of these bicuspid valves are, or become, obstructive placing great strain on the pumping chamber below which must work much harder to push blood forward into the circulation.

The Starr-Edwards design enjoyed some early successes in aortic valve replacements. However, as with the mitral replacements, problems with clotting, stroke, obstruction, inadequate hemodynamics across the valve etc. were seen. Other valve designs were created, but all with similar complications. It was clear to some surgeons that a better alternative needed to be created. With the usefulness of the heart-lung machine which permitted the surgeon to operate inside the living human heart, the challenge was now to design a replacement heart valve that was not prone to such complications.

Mr. Donald Ross, working at Guy's Hospital in London became interested in replacing the aortic valve with a human graft. This concept was bold, yet logical. The human pulmonary autograft was designed the same way nature intended for a normal aortic valve to be. Thus it had the potential to be a truely ideal replacement for the diseased valve. Before this could be accomplished, many surgical and technical challenges remained to be overcome.

One of the first challenges was designing an operative technique whereby a semilunar valve could be sewn to the remaining aortic annulus after removal of the diseased valve. Mr. Ross steadily developed these techniques in his laboratory at Guys Hospital, London during the early 1960's. On July 24, 1962, Mr. Ross accomplished the first implantation of a human cadaver valve in the aortic (subcoronary) position. In August of the same year, Sir Brian Barrett-Boyes at the Green Lane Hospital in New Zealand accomplished the same feat. Both surgeons forged ahead with the concept of replacing the diseased aortic valve with a human cadaver transplant, subsequently known as a homograft. Within three and 1/2 years, Mr. Ross had performed 110 human aortic homograft replacements, achieving progressive improvements in post-operative survival. However, it was still many years before these intrepid surgeons could perfect the difficult surgical technique of sewing the free-hand human valve into place without any distortion and leakage. And there remained considerable problems with procurement and storage of human cadaver heart valves. Attempts to sterilize the grafts with irradiation and/or chemicals such as beta-propriolactone caused premature failure of the grafts and these techniques were later abandoned. In fact, the declining long term results and limited availability discouraged many surgeons from even attempting the operation with homograft substitutes. In 1972, the first animal tissue heart valves became available and most surgeons turned to this new alternative which was quickly made available in quantities to meet the clinical demand.

In this same year, Mr. Ross reported the first successful use of freeze-drying or cryopreservation techniques for long term shelf storage of procured valves. Subsequently Mark O-Brien from Brisbane, Australia reported a standardized technique of antibiotic sterilization followed by controlled rate freezing and cryopreservation of human cadaver valves. Dr. Kirklin, one of Americas foremost congenital heart surgeons, imported the O'Brien storage techniques to his busy center in Birmingham Alabama in 1981. This eventually lead to a commercial venture solely to procure, store, and distribute homograft valves and tissue for surgeons throughout the country. This was the first industrial effort to standardize the methods of valve processing and quality control not previously available.

While the field of mechanical and/or animal tissue replacement valves developed rapidly, Ross, Barrett-Boyes, and a few others continued to develop the concept that the best replacement for the disease aortic valve was another human aortic valve. However, problems with this approach also arose. Despite the initial promise of this technique, the human cadaver aortic replacements (i.e. homografts) began to wear out, leading to leakage. And there continued to be difficulties with surgical implantation techniques, size mismatching, and limited supply and storage problems.

At Stanford University in Palo Alto, California, Drs. Lower and Shumway performed an initial set of experiments in animals where the pulmonary valve was transplanted to the aorta to prevent regurgitation. They never did attempt this in humans. Donald Ross was the first to propose that the native pulmonary valve could be transplanted to the aortic position in actual patients. This operation provided a major step toward an ideal aortic valve replacement for the following reasons. Firstly, the pulmonary valve has the same 3 leaflet configuration as the normal aortic valve. Secondly, the pulmonary valve is roughly the same size as the aortic valve within the same patient, making surgical sizing less problematic. And finally, the supply problem was partly solved since every patient carried his/her own pulmonary valve to begin with. Fortunately, the pulmonary valve was rarely the site of attack for rheumatic fever or other pathology, making it a likely donor for the aortic position. What remained was to effect a replacement for the donated pulmonary valve, and the evolution of surgical techniques to accomplish the feat. To this latter goal, Mr. Ross has dedicated an entire surgical career, proving the success of his concept only after almost 30 years of diligent work.

The first pulmonary autotransplant was performed by Mr. Ross at Guy's Hospital on June 8, 1967, and the patient is still doing well 28 years later. In the 1990s, surgeons around the world are finally understanding the advantages of the Ross procedure, and endeavoring to duplicate the techniques and results pioneered by Mr. Ross. In the United States, interest in the pulmonary autotransplant did not begin until the late 1980's when Dr. Ronald Elkins at the University of Oklahoma and Dr. Lorenzo Gonzalez-Lavin of the Deborah Heart-Lung Institute of New Jersey took up the procedure. An international registry of Ross patients is now being maintained by Dr. James Oury of The International Heart Valve Center at St. Patricks, Hospital and in Missoula, Montana. The Registry currently includes almost 2000 patients operated by 196 different surgeons, most of them beginning programs within the last 5 years.

Today, the name "Ross procedure" represents a transplant of the patients own pulmonary valve to the aortic position, with reconstruction of the missing pulmonary valve using a human cadaver homograft. There are several variants of Dr. Ross' original surgical technique. The manner and placement of the donated valve can also differ, as will be discussed. The sequence, or steps in the operation, as well as the suture techniques also vary from center to center. However, the fundamental principles remain the same throughout. The Ross procedure currently is the only aortic valve operation that replaces the diseased aortic valve entirely with native tissue. Anticoagulant drugs are not needed post-operatively. The rates of infection and stroke are negligible, and certainly far lower than with any other valve replacement. And finally, the longevity of the operation has now being verified. Over an average of 18 years, only 15% of patients will need a second valve operation. The long term freedom from complications and reoperations has made the Ross procedure the modern choice for aortic valve replacement in children and adults with a long (> 20 years) life expectancy. It is the ideal for young women with aortic valve disease who are planning to bear children and other individuals who have a contraindications to anticoagulation (i.e. Coumadin).

Despite the advantages of the Ross in many patients, this procedure is more difficult and time-consuming than any other surgical procedure on the aortic valve. In addition, despite the modern emphasis on organ donation, replacement homografts for the donated pulmonary valve remain relatively scarce. Thus, the Ross operation is not for every patient with aortic valve disease. A separate discussion of the surgical indications and contraindications is included in this Learning Center presentation for your review.

Ross Procedure Sections: Introduction | History | Anatomy | Pros & Cons | Patient Selection | Technique | Results | Pediatric Ross

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