Prosthetic valve implantation has revolutionized the management of valvular heart disease . The original concept valve was a ball in a cage valve , still considered as a fascinating discovery. It was conceived by the young Dr Starr and made by Engineer Edwards .This was followed by long hours of arguments, debates and experiments that ran into many months . The silent corridors of Oregon hospital Portland USA remain the only witness to their hard work and motivation. At last, it happened , the first human valve was implanted in the year 1960. Since then . . . for nearly 50 years these valves have done a seminal job for the mankind.
With the advent of disc valve and bi-leaflet valve in the later decades of 20th century , we had to say a reluctant good-bye to this valve.
There is a lingering question among many of the current generation cardiologists and surgeons why this valve became extinct ?
Starr and Edwards with their child !
We in India , are witnessing these old warrior inside the heart functioning for more than 30 years.From my institute of Madras medical college which probably has inserted more Starr Edwards valve than any other during the 1970s and 80s by Prof . Sadasivan , Solomon victor , and Vasudevan and others .
It is still a mystery why this valve lost its popularity and ultimately died a premature death.The modern hemodynamic men working from a theoretical labs thought this valve was hemodynamically inferior. These Inferior valves worked like a power horse inside the hearts the poor Indian laborers for over 30 years.
A Starr Edwards valve rocking inside the heart in mitral position
The cage which gives a radial support* mimic sub valvular apparatus, which none of the other valves can provide.
* Mitral apparatus has 5 major components. Annulus, leaflets, chordae, pap muscle, LV free wall.None of the artificial valves has all these components. Though , we would love to have all of them technically it is simply not possible. The metal cage of Starr Edwards valve partially satisfies this , as it acts as a virtual sub valvular apparatus.Even though the cage has no contact with LV free wall, the mechano hydrolic transduction of LV forces to the annulus is possible .
Further , the good hemodyanmics of this valve indicate , the cage ensures co axial blood flow across the mitral inflow throughout diastole. .Unlike the bi-leaflet valve , where the direction of blood flow is determined by the quantum of leaflet excursion in every beat . In bileaflet valves each leaflet has independent determinants of valve motion . In Starr Edwards valve the ball is the leaflet . In contrast to bi-leaflet valve , the contact area of the ball and the blood in Starr Edwards is a smooth affair and ball makes sure the LV forces are equally transmitted to it’s surface .
The superiority of bi-leaflet valves and disc valves (Over ball and cage ) were never proven convincingly in a randomized fashion . The other factor which pulled down this valve’s popularity was the supposedly high profile nature of this valve. LVOT tend to get narrowed in few undersized hearts. This can not be an excuse , as no consistent efforts were made to miniaturize this valve which is distinctly possible.
Sudden deaths from Starr Edwards valve .
- Almost unheard in our population.
- The major reason for the long durability of this valve is due to the lack of any metallic moving points .
- Absence of hinge in this valve confers a huge mechanical advantage with no stress points.
- A globe / or a ball has the universal hemodynamic advantage. This shape makes it difficult for thrombotic focus to stick and grow.
Final message
Science is considered as sacred as our religion . Patients believe in us. We believe in science. A good durable valve was dumped from this world for no good reason. If commerce is the the main issue ( as many still believe it to be ! ) history will never forgive those people who were behind the murder of this innocent device.
Cardiologists and Cardio thoracic surgeons are equally culpable for the pre- mature exit of this valve from human domain. Why didn’t they protest ? We can get some solace , if only we can impress upon the current valve manufacturers to give a fresh lease of life to this valve .
http://www.heartlungcirc.org/article/S1443-9506%2810%2900076-4/abstract
Dr.S.Venkatesan MD 