PHILADELPHIA – At 2 years post surgery, safety and efficacy outcomes for the Resolute zotarolimus-eluting coronary stent were similar between non–insulin-requiring patients with diabetes and those without diabetes.
Moreover, even the outcomes for the insulin-requiring patients were superior to results seen with other drug-eluting stents (DES) that have been published in the literature, said Dr. Scott W. Lee, of the department of medicine at Loma Linda (Calif.) University and medical director of global clinical research for Medtronic Diabetes, Northridge, Calif.
Patients with diabetes and coronary artery disease have significantly higher event rates because of endothelial dysfunction, impaired platelet function, altered coagulation/fibrinolysis, and increased smooth muscle proliferation. "From a surgery point of view, many patients with diabetes and heart disease were not even candidates for stent placement 20 years ago. They immediately went on to bypass surgery because of the complexity of their coronary artery disease," Dr. Lee commented.
Since then, current revascularization guidelines support the use of drug-eluting stents for the treatment of obstructive coronary artery disease in patients with diabetes. In March of this year, the Food and Drug Administration approved the Resolute stent for patients with symptomatic ischemic heart disease, including those with diabetes.
In a previous pooled analysis of data on 5,130 patients from five of Medtronic’s clinical trials on the Resolute DES, 878 of the total 1,535 patients with diabetes were compared with 1,302 diabetes patients with DES from the literature in order to define a performance standard. The rate of target vessel failure for the 878 Resolute patients at 12 months was found to be 7.8%, significantly less than the 14.5% seen in the literature among diabetes patients who received other drug-eluting stents. At 24 months, target vessel failure was still lower, at 12.1%, Dr. Lee noted.
Now, new 2-year data come from a post hoc descriptive analysis of the 878 from the Medtronic trials who were matched with 1,903 Resolute stent recipients without diabetes. Even with the same extent of vessel disease, the patients with diabetes had higher metabolic risk. They were slightly older (65.2 vs. 63.6 years) and were more likely to have hypertension (88% vs. 73%) and hyperlipidemia (86% vs. 76%). Males made up a smaller proportion of the diabetic group, 66% vs. 74%.
Target lesion failure – defined as cardiac death, target vessel myocardial infarction, or target lesion revascularization – was higher among those with diabetes at 2 years, 9.6% vs. 7.1%. However, that 9.6% is still "far lower" than the 14.5% published rate in the literature for DES in patients with diabetes, Dr. Lee noted.
When the diabetes patients were further divided into the 250 who were insulin requiring (including both type 1 and type 2 patients) and the 628 who were not, there was a continuum of risk: Target lesion revascularization rates by 2 years were similar between the non–insulin-requiring patients, 4.3%, and the nondiabetics, 3.4%. Among the insulin-requiring diabetes patients, 6.5% had target lesion revascularization.
Cardiac death/myocardial infarction rates were also similar between the non–insulin-requiring diabetic group and the nondiabetics, at 3.9% and 4.1% respectively, and were higher among the insulin-requiring diabetes patients, at 8.6%. "Again, this event rate is still lower than what is in the published literature," Dr. Lee noted.
Stent thrombosis rates were low – less than 1% – across all three groups, he said.
"I think it’s reassuring that there are other options available with regard to acute disease management that are specifically outcome driven," Dr. Lee concluded.
There are plans to study the Resolute DES in diabetes patients in a randomized, prospective study, he said in response to an audience member’s question.
In an interview, session moderator Dr. Alan Garber commented, "This study is very interesting. ... Restenosis has really plagued the patients with diabetes. Thus far, drug-eluting stents have not produced the relief [that] we would like to see in patients with diabetes. Things are better, to be sure, but they haven’t normalized restenosis rates in diabetes patients, compared to nondiabetic patients. This looks to be a substantial advancement in improving rates of restenosis that, although not normal, are closer to normal," said Dr. Garber, professor of medicine, biochemistry and molecular biology and molecular and cellular biology at Baylor College, Houston.
But, he added, "It’s not a head-to-head study. It’s a retrospective post-hoc analysis, but it looks to be better and therefore would justify doing a head-to-head prospective trial. I think cardiologists should consider [using Resolute in patients with diabetes], but a definitive randomized prospective head-to-head trial would be required to be sure."