As drug-eluting stents increasingly co-opt the lucrative bypass surgeries that have kept many a hospital afloat, researchers are gearing up to launch a powerfully sized test of the technology in diabetic patients.
Cardiologists are increasingly turning to the new and high-priced stents to prop open the clogged arteries of an ever-fattening population-and in doing so, are thinning profit margins in hospital cardiovascular suites. Diabetics represent a large portion of those patients.
Diabetes is considered an emerging epidemic in the U.S. with 16 million confirmed cases and another 20 million people at high risk for developing it, said Valentin Fuster, director of the cardiovascular center at Mount Sinai Medical Center in New York, which will be leading the clinical trial. Coronary artery disease accounts for 80% of all deaths among diabetics, compared with 30% among nondiabetics.
Unhampered by the device industry's vested interests, the approximately five-year trial will encompass 2,400 patients at 100 facilities around the world, including 70 in the U.S. The patients will be randomized, with half undergoing coronary artery bypass grafts, which until now have been the standard treatment for diabetics with coronary artery disease, and the other half undergoing angioplasty procedures that will employ the ground-breaking technology.
The study, dubbed the Freedom trial, is being funded with a $25 million grant from the National Heart, Lung, and Blood Institute. Fuster, the grant recipient, said the study would launch Sept. 1 with results after three to five years of patient follow-up becoming available six years from now. Boston Scientific Corp. and Cordis Corp., the two highly competitive companies that have drug-eluting stents on the market, agreed to supply the stents for free, but the trial will be brand-neutral and only seeks to determine, in general, if stenting transcends bypass surgery for diabetic patients, Fuster said.
Besides pitting angioplasty against bypass surgery in this particular patient population, the researchers will recruit another 2,000 patients to build a large registry to serve as a basis for other studies on diabetic patients with cardiac disease. The studies will investigate such issues as genetic markers for progression of the disease, aspirin-resistance and cognitive impairment as a result of surgery, Fuster said.
"This is very unique and certainly the most complex (clinical trial of its kind) and fascinating because it really goes to a group that is growing rapidly in this country-diabetes and obesity," he said.
The study echoes a series of studies in the early 1990s that compared bypass surgery with angioplasty for patients with more than one blocked vessel. The bypass angioplasty revascularization investigation trial enrolled 1,829 patients who were followed for an average of 5.4 years. The researchers found no significant difference between procedures in five-year survival for patients with multivessel disease-except for diabetics, who fared significantly better with bypass surgery. Based on the studies, the National Institutes of Health issued a clinical alert in 1995 recommending bypass surgery over angioplasty for diabetic patients. The alert was issued even after several major advances in both surgical approaches and has had little effect on actual practice, according to Fuster.
Since the introduction of drug-eluting stents in the U.S. market in April 2003, hospitals have been steeling themselves for a precipitous decline in bypass surgeries as a new population of sickly patients, particularly diabetics, migrates to angioplasty procedures. The drug-eluting wire mesh scaffolds, which are designed to prevent the formation of scar tissue after a clogged artery is propped open, are quickly overtaking the older generation of bare-metal stents-at nearly three times the cost (March 15, p. 12).
Thomas Love, director of surgery at 418-bed United Hospital in St. Paul, Minn., said drug-eluting stents are employed in well over 85% of all angioplasties performed at the hospital, and diabetic patients, who typically have complicated, smaller vessels, are getting them virtually 100% of the time.
The hospital has seen a steady decline in bypass surgeries over the last few years, which has only been exacerbated by drug-eluting stents, Love said. About three years ago, United cardiac surgeons performed 800 bypass surgeries per year. Last year volume was halved to 400, and this year only 200 to 300 bypass surgeries will be performed. Diabetics are migrating to angioplasty as well. "Stents seem to be the way to go with diabetics," Love said.
Financially speaking, the sea change in cardiac care won't be a revenue boon for Mount Sinai even though it is one of the top hospitals in New York that perform angioplasty. The hospital makes more money on bypass than on angioplasty though profit margin never drives clinical decisions, said Deborah Marin, Mount Sinai's chief medical officer and executive vice president. As is the case everywhere, bypass surgery volumes have been plummeting, she said. Meanwhile, Mount Sinai cardiologists are reaching for drug-eluting stents over bare-metal stents more than 80% of the time, she added.
"We're very worried from a fiscal perspective," Marin said. "The cost of drug-eluting stents is not equal to reimbursement."
Still, the Freedom trial is an important one that will "give a nonindustry bent" on the angioplasty vs. bypass surgery issue, Marin said. "It is such a large, multicenter study that it will erode away the bias of one stent against another. I think it's going to give very definitive answers in terms of this population of patients," she said.
Cordis is looking forward to the trial results with confidence, said Terri Mueller, a company spokeswoman. "The Cypher stent has already demonstrated excellent clinical performance in difficult-to-treat patients, including diabetics," she said. The company just announced the results of a trial pitting bypass surgery against the Cypher in the treatment of multivessel disease, she noted. The trial involved 606 patients at 45 European centers.
Officials at Boston Scientific were not available for comment, a spokeswoman said.