AHA 2008: Revascularization, MI, and Mortality Benefits at Three Years in Diabetic Patients Treated With Drug-Eluting Stents

November 10, 2008

November 10, 2008 (New Orleans, Louisiana) — Three-year data from the Massachusetts stent registry have shown the use of drug-eluting stents in a real-world diabetic patient population is associated with reduced mortality, MI, and target vessel revascularization (TVR). The results, say investigators, highlight the preserved efficacy of drug-eluting stents observed in other randomized trials and also suggest no increased safety concerns in long-term follow-up.

Dr Laura Mauri

"I would say that what we see consistently from the randomized trials is that there is clear efficacy in the need for repeat revascularization procedures," said senior investigator Dr Laura Mauri (Brigham and Women's Hospital, Boston, MA). "That is now augmented by the fact that there is excellent safety in patients who have a similar ability to take dual antiplatelet therapy. I think that's an important caveat. We have to judge and get to know our patients as individuals and determine [the type of stent] on a case-by-case basis."

Presenting the results today during the late-breaking clinical-trials session here at the American Heart Association 2008 Scientific Sessions, Mauri pointed out that patients with diabetes mellitus have a higher prevalence of ischemic heart disease, and PCI has limitations in this population. Diabetic patients, for instance, have higher rates of restenosis and higher rates of periprocedural MI and mortality, as well as higher event rates in follow-up.

"Diabetes has been an important area to look at the safety of drug-eluting stents because there have been conflicting data regarding safety in this important subset of patients," said Mauri. "It's also a patient population that is rapidly growing across the world, certainly in the US, and now represents approximately one-third of all angioplasty performed."

The results are also published online in Circulation [1].

Mortality Benefit Surprising

It's a patient population that is rapidly growing across the world, certainly in the US, and now represents approximately one-third of all angioplasty performed.

The Massachusetts registry includes all patients treated with stents between April 1, 2003 and September 30, 2004 at non-US government hospitals in the state. Mauri and colleagues have previously presented two-year results for the entire registry population and two-year results for acute MI patients treated with a drug-eluting stent. For the current analysis, the researchers looked specifically at diabetic patients--more than 5000 patients in total--and used propensity-score matching to be able to evaluate outcomes at three years in 1476 patients treated with a drug-eluting stent and 1476 patients treated with a bare-metal stent.

In the propensity-score analysis of matched patients, researchers showed significantly lower rates of TVR among those treated with the drug-eluting stent. In addition to efficacy, there was also a safety benefit, with absolute mortality rates 3.2% lower and MI rates 3.0% lower in the drug-eluting stent arm.

Propensity Score-Matched Risks and Matched Risk Differences at Three Years in Diabetic Patients Treated With Drug-Eluting vs Bare-Metal Stents

Outcome Drug-eluting stents, n=1476 (%) Bare-metal stents, n=1476 (%) Rate difference p
Death 17.5 20.7 -3.2 0.02
MI 13.8 16.9 -3.0 0.02
TVR 18.4 23.7 -5.4 <0.001

"I wouldn’t make a blanket statement, but, in general, there is great benefit to the use of drug-eluting stents in diabetic patients, and there does not appear to be a trade-off in terms of safety," said Mauri.

During a morning press conference announcing the results, Mauri said they were surprised by the data but speculated that longer duration of antiplatelet therapy among patients treated with the drug-eluting stent, usually between three to six months compared with just one month among those treated with a bare-metal stent, had a possible effect on the mortality findings. In addition, she said that patients who received a drug-eluting stent underwent more complete revascularization, with more vessels treated, and this also could have had an effect on death rates. Finally, simply preventing restenosis, as was observed, could translate into a mortality benefit at three years.

Commenting on the findings, Dr David Williams (Brown University, Providence, RI) said the mortality reduction with drug-eluting stents in diabetic patients is provocative, but the advantage is not firmly established.

"The mortality benefit might only show up in the more complicated patient," said Williams. "The original patients are sort of vanilla patients that we put into randomized trials to get the devices approved, but the patients being treated in daily practice are much more complicated than that. . . . It's not unusual that we see the most potent therapy showing a benefit in the sicker patient."

Williams has also published data on the use of different stent types in this patient population and observed similar, but not entirely consistent, findings. Although there was a reduction in repeat revascularization with the drug-eluting stent, his group did not observe a reduction in death or MI among insulin-requiring diabetics. They did, however, observe a reduction in death and MI patients not requiring insulin.

Like Mauri, Williams said drug-eluting stents are favored over bare-metal stents in diabetic patients, but the selection greatly depends on the patient's ability to take dual antiplatelet therapy for sustained periods of time. Investigators did not present or publish an analysis of the benefit stratified by drug-eluting stent type.

The Massachusetts Department of Public Health sponsors the registry. Mauri reports honoraria from Abbott vascular, Boston Scientific, Cordis, and Medtronic Vascular.

  1. Garg P, Normand SL, Silbaugh TS, et al. Drug-eluting or bare-metal stenting in patients with diabetes mellitus. Circulation 2008; DOI: 10.1161/circulationaha.108.820159. Available at: https://circ.ahajournals.org.

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