Consider this problem. A young or middle aged patient needs an aortic valve replacement. Perhaps she was born with a bicuspid valve, or perhaps she grew up in the East and had rheumatic heart disease. Regardless, her aortic valve is end stage and must be replaced. She may be pregnant. What do you do?
The current practice is to give these subjects a mechanical aortic valve. Older subjects would get a tissue (bioprosthetic) valve, but the latter have shorter lives and would almost certainly necessitate replacement after 10 years or so.
Therefore, despite the daunting prospect of lifelong anticoagulation, mechanical aortic valves are preferred in younger subjects.
Donald Ross, British cardiac surgeon, thought of an alternative in 1967. Working at Guy's Hospital, London, he replaced a diseased aortic valve with the patient's own pulmonary valve- an autograft. He then put in a homograft (a cadaveric valve of human origin rather than porcine valve) in the vacant pulmonary position to complete the switch.
His rationale was that a living valve would be physiologically more suitable, the pulmonary valve would share many of the aortic valve's attributes, there would be no immunologic rejection and anticoagulation would be avoided. The background to this was that Star & Edwards had pioneered the first mechanical aortic valve prosthesis in 1960 across the pond, and two years later, Ross himself had performed an aortic valve replacement with a cadaveric graft.
He wasn't happy though. The homografts simply did not last long enough in the aortic position.
Over the next few years, the Ross procedure gained acceptance and was performed in thousands of patients. However, it gained a reputation for being a technically challenging procedure and as the new generation of mechanical valves became available, it became less popular despite the fact that 80% of transplant recipients survived 20 years or longer without re-operation.
In the current issue of JAMA Cardiology, Mazine & colleagues publish a mata-analysis that looks back at five decades of the Ross procedure. Comparing around 1500 such procedures with just over 1900 mechanical valve replacements in young to middle aged patients, they found that the Ross procedure led to reduced all cause mortality, longer survival, better quality of life, haemodynamic performance and left ventricular function than mechanical valves. Rates of major bleeding & stroke were less frequent with the Ross procedure. As expected, re-operations were marginally less common with mechanical valves. These days, most such re-operations would be in the nature of modern percutaneous procedures- TAVR.
Despite the generally held view that the Ross procedure is technically more challenging, peri-operative mortality & morbidity did not differ in the 2 groups. Subjects who had mechanical valves were at a higher risk of needing a permanent pacemaker subsequently.
The Ross procedure cannot be performed in all patients. It is best avoided in those with familial aortopathy and in those with hereditary or acquired connective tissue disease.
It took a while, but after half a century, Donald Ross's groundbreaking procedure has been finally vindicated.
The current practice is to give these subjects a mechanical aortic valve. Older subjects would get a tissue (bioprosthetic) valve, but the latter have shorter lives and would almost certainly necessitate replacement after 10 years or so.
Therefore, despite the daunting prospect of lifelong anticoagulation, mechanical aortic valves are preferred in younger subjects.
Donald Ross, British cardiac surgeon, thought of an alternative in 1967. Working at Guy's Hospital, London, he replaced a diseased aortic valve with the patient's own pulmonary valve- an autograft. He then put in a homograft (a cadaveric valve of human origin rather than porcine valve) in the vacant pulmonary position to complete the switch.
His rationale was that a living valve would be physiologically more suitable, the pulmonary valve would share many of the aortic valve's attributes, there would be no immunologic rejection and anticoagulation would be avoided. The background to this was that Star & Edwards had pioneered the first mechanical aortic valve prosthesis in 1960 across the pond, and two years later, Ross himself had performed an aortic valve replacement with a cadaveric graft.
He wasn't happy though. The homografts simply did not last long enough in the aortic position.
Over the next few years, the Ross procedure gained acceptance and was performed in thousands of patients. However, it gained a reputation for being a technically challenging procedure and as the new generation of mechanical valves became available, it became less popular despite the fact that 80% of transplant recipients survived 20 years or longer without re-operation.
In the current issue of JAMA Cardiology, Mazine & colleagues publish a mata-analysis that looks back at five decades of the Ross procedure. Comparing around 1500 such procedures with just over 1900 mechanical valve replacements in young to middle aged patients, they found that the Ross procedure led to reduced all cause mortality, longer survival, better quality of life, haemodynamic performance and left ventricular function than mechanical valves. Rates of major bleeding & stroke were less frequent with the Ross procedure. As expected, re-operations were marginally less common with mechanical valves. These days, most such re-operations would be in the nature of modern percutaneous procedures- TAVR.
Despite the generally held view that the Ross procedure is technically more challenging, peri-operative mortality & morbidity did not differ in the 2 groups. Subjects who had mechanical valves were at a higher risk of needing a permanent pacemaker subsequently.
The Ross procedure cannot be performed in all patients. It is best avoided in those with familial aortopathy and in those with hereditary or acquired connective tissue disease.
It took a while, but after half a century, Donald Ross's groundbreaking procedure has been finally vindicated.
No comments:
Post a Comment