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Brian P. Priest, MD, Cardiac Surgery
The Chester County Hospital and Health System
Published: February 28, 2011
Fifty years ago, the first artificial heart valves were implanted in adults for diseases of the aortic and mitral valves. These valve replacements required lifelong blood thinners, a nine-inch chest incision and placement on a cardiopulmonary bypass machine; at the time these were acceptable trade-offs in light of the benefits of the procedures, but the eventual goals were to find some way around them.
By 1972, heart valves made from pig and horse tissue could be implanted without the need for blood thinners, but these valves had a limited life span. Subsequent special treatment of these valves expanded their duration to 15 to 20 years, but the implantation still required a large chest incision and a bypass machine.
About 15 years ago, the drive to reduce the size of the chest incision began. Currently, most isolated aortic valve or mitral valve surgery can be done through a small three-inch incision on the right side of the chest. In 90% of mitral valve cases, the valve can be repaired rather than replaced.* In most instances, these minimally invasive procedures are done between the ribs and no bones are broken in the process.
But despite better valve replacements, smaller incisions and the ever-increasing ability to repair rather than replace mitral valves, the cardiopulmonary bypass machine still remains; fortunately, new technologies may reduce its necessity. Ten years ago, the first "stented" aortic valve replacement was performed in Europe. In this procedure, a valve implant was affixed to a large metal wire stent and was directed across the aortic valve opening. The stented valve was then deployed by expanding the stent in the aortic valve position with a large balloon device. This procedure can often be done via a large artery in the groin and therefore no longer requires the cardiopulmonary bypass machine. This procedure called TAVI (trans-catheter aortic valve implantation) has been trialed in the United States recently and has shown significant improvement in survival for patients who were ineligible for open-heart surgery. This new technology will likely be released for use by the end of 2011 for patients who are not routine surgical candidates. Other catheter-based procedures for the replacement and repair of mitral valves are also being tested in Europe and the United States.
These new technologies require the build-out of innovative "hybrid" operating rooms, necessitate greater cooperation between cardiologists and cardiac surgeons, and will result in an increase in the number of adult valve procedures. Soon the Chester County community and other areas outside of urban academic medical centers will have local access to these new procedures and cutting-edge technology. In the beginning, these new modalities will be used only on patients who are not deemed surgical candidates. However, as the technology grows and improves, this expertise will be expanded to the general population that requires valve surgery.
After half a century, we can now finally see the end of the road for adult heart valve procedures: no more blood thinners, no more large chest incisions and no more cardiopulmonary bypass machines.
*Aortic valves still usually require replacement.
This article was published as part of the Daily Local News Medical Column series which appears every Monday. It has been reprinted by permission of the Daily Local News.
Last Updated: 3/2/2011