An emerging technique in Europe in which surgeons replace diseased heart valves through catheters rather than with open heart surgery, may have enormous promise for thousands of U.S. patients denied the procedure because they are too fragile.
But more research, some of which is expected to be published next month, is needed to evaluate its comparative benefit, according to a report published yesterday in the Annals of Internal Medicine.
Heart valve disease, in which the valve becomes too narrow, is blamed for about 20,000 deaths a year. About 95,000 open heart surgeries to replace the valve are now performed in the U.S. but about one-third of patients with the condition are denied because they can not undergo general anesthesia for between three and six hours, and a five to six day hospitalization, nor can they withstand the 12 week recovery.
A less invasive option, such as replacement of a damaged valve with prosthetic valves made from bovine or porcine pericardium mounted within a stent and delivered through a catheter, may be their solution. About 15,000 such procedures have been performed globally to date, but in the U.S., the procedure has been limited to clinical trials.
Researchers at the Duke Evidence-based Practice Center prepared the Annals article at the request of the federal Agency for Healthcare Research and Quality. It found that "short-term outcomes are generally good, with successful implantation and 30-day survival rates of 94% and 89%, respectively."
"As the U.S. population ages, the number of patients with heart valve disease will increase so more Americans will need options for safe, effective heart valve replacement," said AHRQ Director Carolyn Clancy, MD said in a statement. "This report identifies what is known about this emerging procedure and where the research is lacking to give patients more options about their treatment."
Unfortunately, of the 62 published studies representing 856 patients that were evaluated by the Duke researchers, direct comparisons between catheter versus traditional surgical valve replacement could not be accurately compared because of differences in patient groups who underwent the procedure.
Clinical trials are underway in the U.S. comparing three arms: valve replacement through a catheter, valve replacement through open heart surgery and medical management of disease. One study is expected to be presented at the Transcatheter Cardiovascular Therapeutics meeting in Washington, D.C. next month.
"Further studies are needed to evaluate factors related to improved long-term results, particularly those that assess the effect of noncardiac conditions on outcomes, and the effectiveness and cost-effectiveness of the various PHVs (percutaneous heart valves) compared with conventional heart valves and other PHVs."