April 13, 2010 -- Less-invasive "valve-in-valve" implants may help repairprosthetic animal-tissue heart valves in people who are not healthy enough to undergo a second open heart surgery, a study shows.
The research is published in the April 27 issue of Circulation.
A second surgery to replace a leaky or faulty valve is considered riskier than the first. An otherwise healthy 80-year-old man has a 5% chance of dying from a secondary aortic valve replacement surgery and a 10% risk of death from a secondary mitral valve replacement surgery, according to information cited in the new study. These risks increase along with any co-existing health problems.
The valve-in-valve surgery, however, is less invasive and thus may be less risky. "This finding may have important implications with regard to valve replacement in patients at prohibitive risk with conventional surgery," report the researchers, who were led by John G. Web, MD, of St. Paul's Hospital in Vancouver, Canada.
Heart valve replacement surgery typically involves replacing the faulty or leaky valve with a pig or cow tissue valve. Mechanical valves last longer than tissue valves, but they increase the risk of other complications.
Replacing Faulty Heart Valves
In the new procedure, surgeons insert the new valve on a balloon-tipped catheter via a small incision made between the ribs or in a blood vessel in the leg. The new valve is then threaded to the heart and placed inside the old valve. The balloon is inflated, widening both valves and letting the new one take over.
In the study, all of the 24 high-risk patients with failed valves survived the initial valve-in-valve procedure. Ten people had failed aortic valves, seven had failed mitral valves, six had failed pulmonary valves, and one had a failed tricuspid valve.
Two men with failed mitral valves died after the initial surgery. The first passed away the day following the procedure and the second died 45 days after the surgery. The other patients were alive with "satisfactory valve function" after a follow-up of several months and in some cases after almost three years, the study showed.
Not every individual would be a candidate for valve-in-valve transplants, the researchers point out. The original artificial valve must be large enough for the new valve to fit inside.
In an editorial published in the same journal as the study, Blase A. Carabello. MD, a professor and vice chairman of medicine at Baylor College of Medicine and the Veteran Affairs Medical Center in Houston, says the new study will help usher in a new era in cardiology.
The new findings "go far beyond the fact that 24 ill patients received valve-in-valve replacement. They focus on the next step in the therapy of valvular heart disease," he writes.
That said, there is still a lot that is unknown about the proper use of this type of therapy, and many questions will need answering before these therapies can be offered to patients.