Abciximab could be a great equalizer for diabetic heart patients
Abciximab could be a great equalizer for diabetic heart patients
When teamed with angioplasty, stenting, new drug gets good outcomes
Despite its "super-aspirin" nickname in the popular press, the anti-clotting agent abciximab isn’t aspirin at all. Still, researchers say it may be responsible for some super feats anyway, such as acting like a great equalizer. They recently found that among diabetic heart patients who undergo balloon angioplasty and stenting, those who also received the new drug could expect nearly the same good outcomes as nondiabetic patients. That’s good news, considering how notorious re-stenosis can be, especially when a patient has diabetes.
Abciximab, a potent anticoagulant sold under the brand name ReoPro, produced a marked reduction in mortality rates for diabetic patients who are predisposed to re-stenosis after balloon angioplasty and stenting.
Most surprising to one analyst was the long-term prevention of re-stenosis for stent patients who received a 12-hour bolus of abciximab after the procedure.
These results from the multicenter study EPISTENT (Evaluation of Platelet IIb/IIIa Inhibitor for Stenting Trial), which included 491 diabetics, were reported in the Dec. 21 issue of the journal Circulation.
Lead author Steven Marso, MD, interventional cardiology fellow at MidAmerica Heart Institute of St. Luke’s Hospital in Kansas City, MO, says the study "is an important step forward" in the effort to improve outcomes for diabetic patients with coronary heart disease, because balloon angioplasty, even with the addition of stenting, has produced outcomes that are "less than ideal," with a re-stenosis rate averaging 25% or more six months after the procedure.
Patients in the EPISTENT study were randomized to three groups:
1. stent and placebo;
2. stent and abciximab;
3. balloon angioplasty and abciximab.
The diabetic patients who received a single bolus of abciximab after stenting got these benefits:
• Their one-year death rate was just 1.2%; those who got the stent and a placebo had a rate of 4.1%.
• Their rate of myocardial infarction was 6.2%, compared to 12.7% in the stent-placebo groups.
• And the balloon-stent-abciximab group’s six-month re-stenosis rate was 8.1%, compared to 16.6% for stent-placebo and 18.4% for balloon-abciximab. The re-stenosis rate with balloon angioplasty alone is (in general in the United States) estimated to be as high as 60%.
The death rate for the ballon-stent-abciximab group is approximately the same as what is found in nondiabetic patients undergoing balloon angioplasty and stenting, which Marso describes as helping to "level the playing field for patients with diabetes."
EPISTENT subjects had single-vessel disease. Balloon angioplasty and stenting were considered appropriate treatments for those patients.
"These results would suggest that the use of stents and abciximab should become a standard of treatment in the vast majority of patients," wrote Eric J. Topol, MD, chairman of the trial and chairman of cardiology at the Cleveland Clinic, in a formal statement.
Topol noted that, based on these results, the addition of abciximab to the standard balloon angioplasty and stent procedure could save 8,000 lives a year. "Approximately 600,000 people will undergo some type of percutaneous coronary revascularization in the U.S. in 1999. If all of these patients were treated with the combination of stents and abciximab, these data would indicate that as many as 8,000 lives could be saved per year."
Angioplasty vs. bypass
Other research has shown the benefit of surgery over ballooning in diabetic patients. In the Bypass Angioplasty Revascularization Investigation (BARI), investigators found their diabetic participants had better outcomes and five-year survival when they went the bypass route. The BARI patients were different from than those in the EPISTENT study, however, because the bypass recipients had multivessel disease.
The diabetics randomized to coronary bypass surgery had a higher five-year survival rate, but more importantly, only 8% of the diabetic patients randomized to surgery had re-stenosis as compared to more than half of the angioplasty group.
"The question of whether stenting plus abciximab might produce results equal to bypass is yet to be answered." says Marso. He cautions that clinicians need to pay particular attention to the contrast dye used in stenting and angioplasty because of the propensity for kidney toxicity in diabetic patients. "We need to be particularly vigilant for anyone with evidence of proteinuria or elevated creatinine levels."
Marso’s EPISTENT findings were enthusiastically supported in an accompanying editorial by Spencer B. King II, MD, professor of medicine and cardiology and director of interventional cardiology at Emory University in Atlanta.
What is particularly surprising is that no earlier studies have shown abciximab to reduce re-stenotic events long after the procedure has been done, he says. So after six months, more patients are spared the pain, risk, and expense of undergoing another procedure.
"The late events probably represent a very different mechanism from the early clotting events. We just didn’t expect it." He adds that the BARI results were originally surprising, too, but eight years of ongoing Emory University research now affirms the improved long-term bypass survival rate for diabetics.
King pointed out in his editorial that Marso’s study compares hypertensive, obese diabetic patients and nonhypertensive, nonobese, nondiabetic patients. "It will be interesting to compare diabetics with and without insulin resistance in a larger cohort in future trials," King wrote.
He notes that there are many aspects of heart disease in diabetics that are different from the manifestations of the disease in nondiabetics. "They clearly had a more aggressive re-stenosis rate, perhaps because of altered platelet function. It’s a different manifestation of the disease, in my opinion."
King and Marso agree that abciximab may level the playing field as suggested by EPISTENT, giving diabetic patients a chance of survival at least comparable to their nondiabetic counterparts.
"Unless there is some reason not to, on diabetic patients, I use abciximab or some similar drug. I certainly use it on the ones I think have a possibility of an acute thrombotic events," King explains.
[For more information, contact Steven Marso at (816) 932-5742 and Spencer King at (404) 712-4677.]
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