A Tight Spot: Drug-Eluting Stents Seem to Top Other Options for Small-Vessel Disease

A new analysis based on trials using older stent types shows that early-generation sirolimus-eluting stents (SES) rank best in terms of angiographic and clinical outcomes for patients with stenoses in small coronary arteries. The findings suggest that newer-generation DES would be preferred for these patients in contemporary practice.

SES came out ahead of paclitaxel-eluting stents (PES), drug-coated balloons (DCB), BMS, and standard balloon angioplasty for the endpoint of percent diameter stenosis at 6 to 9 months after the procedure. This translated into a significantly lower TLR rate, George Siontis, MD, PhD (University Hospital Bern, Switzerland), and colleagues report in a study published online June 15, 2016, ahead of print in JACC: Cardiovascular Interventions.

Commenting on the study for TCTMD, Giuseppe Biondi Zoccai, MD (Sapienza University of Rome, Italy), said the findings are consistent with current practice, in which DES are the first choice when the vessel is suitable and DCB remain a good option when clinicians and patients want to avoid a permanent metal implant.

On the other hand, standard balloons and BMS “are not reasonable choices any longer,” he said.

Although early-generation SES—namely, the Cypher stent from Cordis/Johnson & Johnson—are no longer available, Biondi Zoccai noted, “we can safely assume that the best new-generation drug-eluting stents are at least as effective and safe as Cypher . . . [and] most likely better.”

The study authors agree, pointing out that new-generation DES have lowered risks of stent thrombosis and repeat revascularization compared with older DES. Nevertheless, they say, “additional randomized trials are warranted evaluating the role of new-generation DES to corroborate the results of this meta-analysis.”

Biondi Zoccai said that future trials likely will not compare newer DES with older stents or DCB, but rather with bioresorbable scaffolds, which currently have some limitations stemming from thicker struts. “Definitely in small vessels it would make sense to have a stent which disappears, even if it is associated with a little bit more restenosis,” he said. For the time being, however, small vessels are widely believed to be a contraindication to bioresorbable stent use—something the US Food and Drug Administration was urged to consider in the recent advisory panel review of the Absorb BVS (Abbott Vascular).

Angiographic, Clinical Superiority

Siontis and colleagues performed a network meta-analysis of 19 randomized trials published between 1998 and 2012 to enable direct and indirect comparisons of various interventions for small-vessel disease. The trials included a total of 5,072 patients, most of whom (62%) presented with stable CAD.

Early-generation SES came out on top in terms of the primary angiographic outcome of percent diameter stenosis, followed by PES (standardized mean difference [SMD] -0.44%), DCB (SMD -0.89%), BMS (SMD -1.43%), and standard balloon angioplasty (SMD -1.58%). DCB did not differ significantly from the last two groups, however.

Looking at absolute differences in percent diameter stenosis, SES provided significant reductions of 18%, 29%, and 32% compared with DCB, BMS, and balloon angioplasty, respectively. The 9% difference versus PES fell shy of statistical significance.

As for clinical outcomes, SES reduced the likelihood of TLR compared with all other approaches, with odds ratios ranging from 0.16 versus balloon angioplasty to 0.39 versus PES. DCB ranked best for MI, although there were no significant differences between all of the interventions, excluding balloon angioplasty. Mortality was comparable across groups.

Some Caveats

In an accompanying editorial, Fernando Alfonso, MD, PhD, and Marcos García-Guimaraes, MD (Hospital Universitario de La Princesa, Madrid, Spain), say Siontis et al “should be commended for selecting this sound methodology to unravel the best evidence currently available from randomized clinical trials comparing coronary interventions in small vessels.”

But they note some caveats, including the varying definition of small vessels across studies and the lack of trials using new-generation DES.

“This study provides robust evidence demonstrating the superiority of first-generation SES compared with other classical coronary interventions in patients with small vessels,” they write. “However, from a practical standpoint, the optimal strategy for the current treatment of these lesions cannot be inferred from the present study, as new-generation DES were not included and first-generation SES and PES are no longer available. . . . Therefore, we are more than ready for dedicated head-to-head randomized clinical trials aimed to confirm the expectations generated by novel DES and novel DCB in this challenging anatomic scenario.”

• Sources:
• Siontis GCM, Piccolo R, Praz F, et al. Percutaneous coronary interventions for the treatment of stenosis in small coronary arteries: a network meta-analysis. J Am Coll Cardiol Intv. 2016;Epub ahead of print.
• Alfonso F, García-Guimaraes M. Optimal coronary interventions in small vessels: is size all that matters? J Am Coll Cardiol Intv. 2016;Epub ahead of print.

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