Sirolimus-Eluting Stents Superior to Paclitaxel-Eluting Stents in Diabetics
Abstract & Commentary
By Andrew J. Boyle, MBBS, PhD, Assistant Professor of Medicine, Interventional Cardiology, University of California, San Francisco. Dr. Boyle reports no financial relationships relevant to this field of study.
Source: Lee SW, et al. A randomized comparison of sirolimus-versus paclitaxel-eluting stent implantation in patients with diabetes mellitus. J Am Coll Cardiol. 2008; 52:727-733.
Diabetic patients are at higher risk for in-stent restenosis and stent thrombosis than their non-diabetic counterparts. Thus, they make up a high-risk subgroup of patients undergoing percutaneous coronary intervention (PCI). As the incidence of diabetes is increasing, we are likely to see greater numbers of diabetic patients undergoing PCI. To date, however, most clinical trials involving PCI have enrolled all-comers, and we, therefore, have to rely on subgroup analysis to determine which therapies are best in this high-risk group. Studies specifically enrolling diabetic patients are warranted.
Lee et al performed a multi-center, randomized, controlled trial among 400 diabetics with angina or documented ischemia and a native coronary artery lesion > 50% who were undergoing PCI. They randomized them after the guidewire had crossed the lesion to receive sirolimus-eluting stents (SES) (n = 200) or paclitaxel-eluting stents (PES) (n = 200). In a 2 X 2 factorial design, they also randomized the patients to dual anti-platelet therapy (aspirin 200 mg daily + clopidogrel loading dose of 300 mg, followed by 75 mg daily for at least six months) or triple anti-platelet therapy (aspirin + clopidogrel + cilostazol loading dose of 200 mg immediately after the procedure and 100 mg twice/day for six months). To confirm the presence of diabetes, all patients had to be taking insulin or oral hypoglycemic agents, or they had to have an elevated fasting glucose level documented. The primary end point of this trial was in-segment restenosis on six-month angiographic follow-up study (defined as in-segment stenosis of at least 50%). The secondary end points included six-month angiographic outcomes such as in-segment late loss and the rate of in-stent restenosis at six months (defined as in-stent stenosis of at least 50%), stent thrombosis, target vessel revascularization (TVR), and major adverse cardiac events (MACE), including death, myocardial infarction (MI), and target lesion revascularization (TLR). Repeat coronary angiography was mandatory at six months after stenting, or earlier if indicated by clinical symptoms or evidence of myocardial ischemia and quantitative coronary angiography (QCA) analysis was performed. Clinical follow-up was to nine months.
There were no differences in baseline characteristics between patient groups. Angiographic success was achieved in 99.5% of cases in each group. The use of glycoprotein IIb/IIIa inhibitors was at the operator's discretion and occurred in 5.5% of the SES group and 3.5% of the PES group (p = ns). Follow-up angiography was performed in 330 patients (82.5%): 176 (88%) SES and 154 (77%) PES patients. In-segment restenosis, the prespecified primary end point, was identified in seven (4.0%) SES and 32 (20.8%) PES patients (p < 0.001).
Other angiographic findings were also better in the SES group vs PES group, including larger in-stent diameter (2.44 ± 0.51 mm vs 2.01 ± 0.67 mm; p < 0.001), smaller percent in-stent restenosis (14.1 ± 15.2% vs 26.3 ± 22.0%; p < 0.001) and lower late loss (0.13 ± 0.43 mm vs 0.53 ± 0.57; p < 0.001). In addition, the pattern of restenosis was more focal in the SES group and more diffuse in the PES group.
The rates of death and myocardial infarction (MI) were the same in the SES-and PES-treated groups; however, there was a lower rate of target lesion revascularization (TLR) in the SES group (2.0% vs 7.5%; p = 0.017).
The combined major adverse cardiac event rate (death/MI/TLR) was lower in the SES group, driven by the lower TLR, despite no difference in death or MI. The addition of cilostazol tended to reduce in-segment restenosis in both SES and PES groups, but the absolute measure was not statistically significant (p = 0.861). Stent thrombosis occurred in one patient in the SES group and none in the PES group over the nine-month clinical follow-up. Lee et al concluded that in diabetic patients, SES implantation resulted in a significantly reduced risk of six-month angiographic restenosis and nine-month TLR or MACE without a significant difference in MI or death compared with PES implantation.
Commentary
This study is welcome because it has specifically addressed the issue of which drug-eluting stent, SES or PES, and is better in diabetic patients in a prospective fashion, rather than relying on subgroup analysis from a study that enrolled all comers. Lee et al have demonstrated a reduction in in-stent restenosis in the SES treated patients, with a subsequent reduction in repeat procedures. This may translate into improved patient satisfaction and reduced costs associated with PCI in SES-treated diabetic patients. These findings are in keeping with the suggestion of reduced in-stent restenosis using SES based on previous registries, meta-analyses, and sub-group analyses from randomized trials. However, it should be emphasized that the follow-up angiography six months in this study and may, therefore, have underestimated the true extent of in-stent restenosis that may have become apparent at later time-points.
Diabetic patients are at higher risk for in-stent restenosis and stent thrombosis than their non-diabetic counterparts.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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