Drug-eluting stents may not offer the early advantage over coronary artery bypass grafts (CABG) seen with bare-metal devices, researchers reported here.
In a single-center observational study, drug-eluting stents and CABG had similar 30-day and three-year outcomes for coronary patients, said James M. Wilson, M.D., of the Texas Heart Institute at St. Luke's Episcopal Hospital in Houston, and colleagues.
The study, presented at the American Heart Association's Conference on Arteriosclerosis, Thrombosis, and Vascular Biology here, represented one of the first reports on outcomes of drug-eluting stents versus bypass grafting.
In previous studies, bare-metal stents had better outcomes at one year that then eroded to equivalence at three years and disadvantage compared with CABG at long-term follow-up, Dr. Wilson said.
"It's a little worrisome that we don't have that early advantage we had with the bare-metal stents," he said. "This surprised us."
Dr. Wilson and colleagues looked at in-hospital and three-year follow-up data from 1,598 unselected coronary-artery patients who underwent isolated primary revascularization by drug-eluting stents or CABG.
Patients were case matched by procedure propensity score to ensure similar patient characteristics between groups. For both, the average age was 64, about 7% had an urgent procedure, about 30% had diabetes, and about 75% had more than one diseased vessel.
Early, 30-day major adverse cardiac and cerebrovascular event findings were:
Similar overall (3.78% CABG versus 5.01% DES, P=NS).
Not significantly different for myocardial infarction between groups (1.67% versus 2.22%, P=NS).
Significantly lower stroke rate with drug eluting stents (1.11% versus 0.11%, P<0.01).
Similar for 30-day mortality (1.67% versus 2.22%, P=NS).
Identical target vessel and target lesion revascularization rates by CABG (0.11% versus 0.11%, P=NS).
Significantly different target vessel and target lesion revascularization rates by drug eluting stents between groups (0.00% versus 1.78%, P<0.01).
For mid-term outcomes, the researchers looked at mortality at three years post-revascularization. They found no statistically significant difference between CABG and drug eluting stents (6.6% versus 9.0%, P=NS).
While drug-eluting stents were expected to offer advantages over bare-metal stents, overconfidence in patient selection appears to have erased any advantage, Dr. Wilson concluded.
"With drug-eluting stents, the data from randomized trials was so exciting I think we began to treat the more difficult lesions with hopes of long-term success," he said.
An FDA advisory panel concluded late last year that drug-eluting stents are safe and effective when used as indicated in stable patients with single-vessel disease. An estimated 60% of the six-million drug-eluting stents implanted worldwide are used off-label in complex lesions and high-risk patients.
"We have a stent that has a reduced likelihood of failure long term but the patients we've chosen to put them in have given away the early advantage," Dr. Wilson said. "If we were to use our patient selection criteria that we used for bare metal stents our outcomes might be more favorable."
Continued follow-up in this and other studies are needed to show how drug-eluting stents stack up to surgery long term, he added.
"What I think is going to be most interesting is when we extend our survival curves out to five to 7.5 years, and maybe those curves start to separate," Dr. Wilson said. "Right now all we can say is they are close enough to each other that we can't make any predictions."
"This is the type of study that will be very helpful," commented Sidney Smith, M.D., of the University of South Florida in Tampa and a past president of the American Heart Association, who was not involved in the study.
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