What Percent Of Pig Heart Valve Replacements Fail?
July 1st, 2009It is one of the most important decisions for patients as they prepare for heart valve replacement surgery. That question is, “Which type of heart valve replacement device should I choose?”
There are several considerations that patients and their caregivers must evaluate relative to this question. Such considerations include durability, patient age, ongoing drug therapy, lifestyle, valve noises, activity levels, etc. I specifically remember creating a pros-and-cons list with Robyn (my wife) for each option prior to my own aortic valve replacement surgery.
Medtronic Mosaic Pig Valve Replacement
Another patient consideration specific to mechanical and tissue valve selection is failure rates. As you can read in prior blogs, patients want to avoid valve replacement re-operations should the device fail while functioning in the human heart.
Unfortunately, I have been unable to locate published heart valve failure rates specific to each type of pig valve, cow valve, mechanical valve and homografts.
However, I just reviewed a very interesting study published by The Washington School Of Medicine about pig valve replacement failure rates that made my eyebrows jump to the top of my forehead. Here are the highlights from that study:
- Pig heart valves used to replace defective aortic valves in human patients failed much earlier and more often than expected.
- Between 2001 and 2005, four out of 106 patients with the pig valves implanted in the aortic position developed severe impairment after less than four years, and the patients required surgery to replace the valves.
- In the four patients affected, the pig valves failed after 3, 14, 19 and 44 months. Each patient underwent a second operation to replace the defective valve with a valve made from cow heart tissue. No patient died as a direct consequence of the pig heart valve impairment.
Jennifer S. Lawton, M.D., a Washington University cardiothoracic surgeon at Barnes-Jewish Hospital, notes that the valves are expected to last 10 to 15 years in patients over 70. All four patients who needed a “redo” operation were over 70.
Dr. Jennifer Lawton – Heart Surgeon
“We noticed an increased incidence of this complication,” says Lawton, associate professor of surgery. “We were very concerned, and we believe it is important for others to know about it. A four percent failure rate may not sound like a lot, but we would not expect that many of the valves to fail in such a short period of time.”
The pig heart valves that failed early were Medtronic Mosaic porcine valves produced by Medtronic. Following an examination of the valve, pathologists noted that the valves’ leaflets had thickened and stiffened making them much less mobile than normal. Plus, the leaflets were covered with numerous bumps, but the exact nature of these tissue growths couldn’t be determined. The cause of early valve failure, whether it is related to patient factors or valve factors, remains unclear, the researchers say.
“After valve replacement surgery, patients typically get an echocardiogram to check valve structure at three, six and twelve months and then yearly after that,” Lawton says. “If symptoms such as shortness of breath, chest pain or light-headedness occur, more frequent exams may be conducted. If patients have had a pig valve implanted, I would tell them that most likely they will be fine, but if they have symptoms they need to see their cardiologist and get an echocardiogram.”
As a result of Dr. Lawton’s findings Barnes-Jewish Hospital and Washington University are no longer implanting the Medtronic Mosaic.
Keep on tickin!
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| About The Author: Adam Pick is a double, heart valve surgery patient and author of The Patient's Guide To Heart Valve Surgery. This unique book integrates clinical research with the personal experiences of 135 former patients to help future patients and their caregivers better understand the problems, the opportunities and the realities of heart valve surgery. To learn more about Adam and his heart valve surgery book, click here. |
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