DES Outcomes Vary by Diabetes Status, Lesion Complexity

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Diabetes increases the need for repeat revascularization after drug-eluting stent (DES) implantation only in patients with complex lesions, according to a study published online March 12, 2014, ahead of print in the Journal of the American College of Cardiology. Yet the higher risk of cardiac death or MI faced by diabetic patients still stands, even in those with more simple lesions.

For the patient-level pooled analysis, researchers led by Gregg W. Stone, MD, of Columbia University Medical Center (New York, NY), reviewed 1-year follow-up data on DES-treated patients from 18 randomized trial databases maintained at the Cardiovascular Research Foundation (New York, NY). Included were the TAXUS, SIRIUS, ENDEAVOR, and SPIRIT series of trials as well as the COMPARE, ACUITY, and HORIZONS-AMI trials. Indications ranged from stable angina to ACS.

In all, 3,467 of 18,441 patients (18.8%) had diabetes.

Diabetes Portends Poor Results

Analysis of 3,167 propensity score-matched pairs showed that the diabetes and nondiabetes groups had similar levels of lesion severity and length, though diabetic patients had slightly smaller vessels.

At 30 days, there were no significant differences in outcome by diabetes status. At 1 year, diabetes independently predicted higher risks of repeat revascularization, cardiac death or MI, and MACE (all-cause death, MI, or TVR; table 1).

Table 1. Outcomes by Diabetes Status at 1 Year

Propensity-adjusted multivariable analysis found no difference in outcomes among diabetes patients regardless of necessity for insulin.

When the matched groups were further stratified according to lesion complexity, diabetic patients with ACC/AHA type B2/C lesions experienced higher rates of repeat revascularization than did their counterparts with type A/B1 lesions. Rates of cardiac death or MI and MACE were higher across the board for diabetic patients than for nondiabetic patients, with no interaction between diabetes and lesion type (table 2). The same patterns were seen when lesion types A, B1, B2, and C were analyzed separately.

Table 2. Diabetes vs. No Diabetes by ACC/AHA Lesion Type

Patients without diabetes had similar levels of TLR and TVR irrespective of whether their lesions were A/B1 or B2/C.

“The findings … demonstrate favorable intermediate-term results in patients with [diabetes] after treatment of non-complex lesions with DES,” the researchers conclude.

“Unfortunately,” they say, “diabetic patients often present with advanced coronary artery disease and left ventricular dysfunction, due in part to impaired sensory perception of ischemia. As the global incidence of [diabetes] is increasing, randomized trials focusing on the early detection and treatment of atherosclerotic coronary disease in diabetic patients might be warranted to determine whether earlier revascularization with DES or CABG, coupled with improved systemic therapies, might improve the prognosis in [diabetes].”

Diabetes Should Not Deter PCI for Non-Complex Lesions

In a telephone interview with TCTMD, Dr. Stone said it makes sense that diabetic patients with “very complex and diffuse multivessel coronary artery disease would have relatively poor outcomes with PCI, whereas most diabetic patients with discrete, isolated lesions on the coronary tree would have a relatively favorable prognosis with PCI. That’s what we found, at least in terms of repeat revascularization procedures.

“However,” he continued, “there’s also another component of diabetes, which relates likely to diffuse inflammation and global vascular atherosclerotic instability, that places diabetic patients at increased risk regardless of the angiographic severity of atherosclerosis. This probably applies to both PCI and bypass surgery.”

Dr. Stone acknowledged that the various DES types may have different outcomes in diabetics, but said he expected that all limus-eluting stents would be consistent.

An implication of the current study, Dr. Stone noted, is that “if patients have multiple complex lesions, they’re most likely going to be served better by bypass surgery…. Whereas if patients have 1 or a few non-complex lesions, the fact that they’re diabetics should not at all inhibit PCI.”

In an editorial accompanying the JACC paper, Stephen G. Ellis, MD, of the Cleveland Clinic (Cleveland, OH), advises that “in general PCI in diabetics should still be reserved for those patients either with acute coronary syndromes or elective patients with relatively simple anatomy at the lower end of diabetic risk spectrum for cardiovascular death or MI. Further, we need better therapies to [quiesce] the diabetic vasculopathy so that focal therapy of specific symptoms-causing stenoses can be associated with better long term outcomes.”

Study Does Not Speak to Which Treatment Is Best

Dimitrios Karmpaliotis, MD, PhD, also of Columbia University Medical Center, cautioned that the analysis, while offering insight into the interplay between diabetes, PCI, and repeat revascularization, must be carefully interpreted.

To begin with, the analysis did not incorporate trials comparing different treatment modalities, he stressed. “It doesn’t tell us whether PCI is better than CABG or medical therapy. It just tells us within the context of PCI which lesions do and do not do well in patients with diabetes,” Dr. Karmpaliotis said, adding that longer-term follow-up is also needed before drawing definitive conclusions.

Moreover, the population is heterogeneous, and by virtue of being derived from randomized trials, is highly selected, he said, adding, “They may not be representative of a real-world, all-comers situation.”

According to Dr. Karmpaliotis, DES PCI "may be a reasonable approach" in diabetic patients with multivessel disease who have well-controlled risk factors and relatively simple lesions. That being said, he added: “Both atherosclerosis and diabetes are essentially systemic diseases. Stents do take care of the acute mechanical issues, but we need to be very aggressive at treating the underlying disease.”

Note: Dr. Stone and several study co-authors are faculty members of the Cardiovascular Research Foundation, which owns and operates TCTMD.

 

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Source:
1. Kedhi E, Généreux P, Palmerini T, et al. Impact of coronary lesion complexity on drug-eluting stent outcomes in patients with and without diabetes mellitus: analysis from 18 pooled randomized trials. J Am Coll Cardiol. 2014;Epub ahead of print.

2. Ellis SG. Presence of diabetes doesn’t matter for PCI outcomes with simple coronary lesions: can that be true [editorial]? J Am Coll Cardiol. 2014;Epub ahead of print.

 

 

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