Valve-in-Valve Implants Effective for High-Risk Patients

April 27, 2010—The American Heart Association announced the publication of a study that found that replacing failing artificial animal-based heart valves by implanting mechanical valves inside them is an effective option for high-risk patients. John G. Webb, MD, et al published the study in Circulation (2010;121:1848–1857).

In the study, 24 high-risk patients in Canada and the United Kingdom whose previous implants failed received transcatheter valve-in-valve implantation. Factors that made the patients in the study risky or ineligible as surgical candidates included two or more previous open-chest surgeries, severe pulmonary hypertension, and various heart or other complications. The procedure was first done approximately 5 years ago, but only isolated cases have been reported on so far, Dr. Webb stated.

According to the American Heart Association, the new study presents data from a significant number of patients and involves all four heart valves. Ten patients in the study had failed aortic valves, seven patients had failed mitral valves, six patients had failed pulmonary valves, and one patient had a failed tricuspid valve. All patients survived the transcatheter procedure, but one mitral valve patient whose implantation was converted to open surgery had a stroke and renal failure and died the next day. Another mitral valve patient died 45 days after the surgery.

The investigators reported that no patient had more than mild regurgitation after implantation. Thirty-day mortality was 4.2%. Mortality was related primarily to learning-curve issues early in this high-risk experience. At baseline, 88% of patients were in New York Heart Association functional class III or IV; at the last follow-up, 88% of patients were in class I or II. At a median follow-up of 135 days (interquartile range, 46–254 d) and a maximum follow-up of 1,045 days, 91.7% of patients remained alive with satisfactory valve function.

The investigators stated that although reoperation is the standard treatment for deteriorated prosthetic valves, this approach has significant risks. They cite calculations from the Society of Thoracic Surgeons that predict an 80-year-old man with no other health problems faces a 5% risk of death for reoperation on an aortic valve, 10% risk for a mitral reoperation, and more substantial risk if he has other complications. Almost all of the patients receiving mitral or aortic valve replacements were elderly (age ≥ 75 years). Patients with pulmonary or tricuspid surgical valves were considerably younger. Those patients typically have congenital heart disease and frequently have required multiple surgeries in the past. Most of the patients were men, but Dr. Webb expects the findings would be consistent in women.

Finally, Dr. Webb observed that previously implanted valves have many different shapes, sizes, and manufacturers, so it is difficult to assess how universally the transcatheter valve implants will function. He advised, “The procedure only works well if the original surgical valve is large enough for the new transcatheter valve to fit inside it. Most surgical valves are large enough, but not all. If the surgical valve is small, the new valve may open more fully than the old valve but not as well as you would like. Nevertheless, generally, the transcatheter valves work very well for treating leaky, failed surgical valves.”