SCAAR: Second-Generation DES Improve Hard Outcomes

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Patients treated with percutaneous coronary intervention (PCI) with second-generation drug-eluting stents (DES) have a lower risk of restenosis, stent thrombosis (ST), and death at 2 years compared with those treated with first-generation DES. Despite these differences, both DES eras achieve better survival than bare-metal stents (BMS), according to a study published January 9, 2012, online ahead of print in the European Heart Journal.

For the retrospective analysis, Stefan James, MD, PhD, of Uppsala University Hospital (Uppsala, Sweden), and colleagues studied data taken from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR) of 94,384 consecutive stent implantations in 61,351 patients from November 2006 to October 2010.

Patients were divided into 3 groups depending on the type of stent implanted. BMS were used in 64,631 patients, first-generation DES in 19,202, and second-generation DES in 10,551.

Drastic Improvement with Newer Designs

Prespecified endpoints including restenosis (assessed by angiographic visual estimation > 50% or by fractional flow reserve ≤ 0.80) and clinically driven TLR as well as definite ST all were lowest with second-generation DES at 2 years (table 1).

Table 1. Clinical Outcomes at 2 Years

 

BMS
(n = 64,631)

First-Generation
DES
(n = 19,202)

Second-Generation
DES
(n = 10,551)

Restenosis

7.4%

5.8%

3.9%

TLR

5.5%

4.9%

3.1%

Definite ST

1.4%

1.3%

0.6%

 
Compared with first-generation DES, second-generation devices were less likely to result in either restenosis (adjusted HR 0.62; 95% CI 0.53-0.72) or definite ST (adjusted HR 0.57; 95% CI 0.41-0.79) out to 2 years. The newer devices held a similar advantage over BMS, also lowering the risk of restenosis (adjusted HR 0.29; 95% CI 0.25-0.33) and definite ST (adjusted HR 0.38; 95% CI 0.28-0.52).

Cumulative risk of TLR by PCI up to 2 years was significantly lower with the newer devices than with older DES (adjusted HR 0.60; 95% CI 0.51-0.70) or BMS (adjusted HR 0.32; 95% CI 0.28-0.38). First-generation DES also improved upon the results of BMS, reducing restenosis (adjusted HR 0.46; 95% CI 0.43-0.51), definite ST (adjusted HR 0.67; 95% CI 0.56-0.80), and TLR by PCI (adjusted HR 0.54; 95% CI 0.50-0.60).

Mortality at 2 years for all patients was 5.6% (6.8% BMS, 3.4% first-generation DES, and 1.9% second generation DES). The risk of death was lower in the second-generation DES group than in the first-generation DES group (adjusted HR 0.77; 95% CI 0.63-0.95) and the BMS group (adjusted HR 0.55; 95% CI 0.46-0.67). Yet even first-generation DES-treated patients obtained lower mortality (adjusted HR 0.72; 95% CI 0.64-0.81) compared with those who received BMS.

‘Very Reassuring’ Results

In a press release, Dr. James said that while less restenosis was expected with second-generation stents, the biggest surprises from these findings were the observed improvements in ST and mortality.

“The low rates of restenosis and stent thrombosis correspond with the results of several recent randomized trials, and this may well translate into mortality reduction in a sufficiently large study population,” he commented.

Dr. James and colleagues attributed the positive results to “improved stent designs with thinner struts and more biocompatible polymers [having] an important impact on drug elution profiles, endothelial coverage, and functional recovery.”

Praising the authors for a “well designed and carefully performed” study, Deepak L. Bhatt, MD, MPH, of Brigham and Women’s Hospital (Boston, MA), told TCTMD in an e-mail communication that the findings reflect the progress made in stent technology over the last several years.

"It is difficult to say anything definitive based on these sorts of nonrandomized comparisons, but it is very reassuring that the newer-generation DES appear to be at least as safe and efficacious as the older ones,” he said, noting that the possibility of less ST and death with newer-generation DES, particularly in comparison with BMS, was “an exciting observation” that should be confirmed in randomized clinical trials.

Potential Confounders

Similarly, the authors warn that their “results need to be interpreted with caution,” as differences in baseline characteristics could have altered the findings. However, they state that the large sample size could also have provided “more power to detect differences in low-frequency events such as death.”

Gregg W. Stone, MD, of Columbia University Medical Center (New York, NY), told TCTMD in a telephone interview that though a randomized trial would be needed to confirm these findings, there may no longer be any clinical equipoise.

“People are so confident that the newer drug eluting stents are much more effective than bare metal stents, and it would no longer be ethical to randomize most patients,” he said. “The one situation where it might still be ethical to do a randomized trial between drug eluting stents and bare metal stents would be in patients with STEMI because in that situation, bare metal stents are still used in approximately 50% of patients.”

In addition, Dr. Bhatt said that the “potential impact of different durations of dual antiplatelet therapy for BMS versus DES may have influenced the results,” adding that ongoing randomized trials of different durations of dual antiplatelet therapy will be able to answer this question.

Although “the longer duration of dual antiplatelet therapy prescribed with DES may reduce long-term adverse event rates independently of stent selection,” the authors note, “this limitation does not apply to the comparison between old and new DES for which the recommended duration of dual antiplatelet therapy was the same.”

Study Details

Stent length, number of restenotic lesions, and presence of chronic total occlusions at the index procedure were higher in both DES groups vs. BMS, with a higher rate of restenotic lesions in the first- vs. second-generation DES patients.

Patients were treated with devices including:

  • BMS: Multilink, Multilink MiniVision, and Flexmaster (Abbott Laboratories, Abbott Park, IL), Driver and Micro Driver coronary (Medtronic, Santa Rosa, CA), Liberté (Boston Scientific, Natick, MA), Braun Coroflex Blue (B. Braun Melsungen AG, Berlin, Germany), and Chrono stent (CID, Saluggia, Italy)
  • First-generation DES: Cypher and Cypher Select (Cordis/J&J, Miami, FL), Taxus Express and Taxus Liberté (Boston Scientific), and Endeavor (Medtronic)
  • Second-generation DES: Endeavor Resolute (Medtronic), XienceV, Xience Prime (Abbott Laboratories), and Promus and Promus Element (Boston Scientific)

 


Source:
Sarno F, Lagerqvist B, Fröbert O, et al. Lower risk of stent thrombosis and restenosis with unrestricted use of ‘new-generation’ drug-eluting stents: A report from the nationwide Swedish Coronary Angiography and Angioplasty Registry (SCAAR). Eur Heart J. 2012;Epub ahead of print.

 

  • Dr. Bhatt reports receiving research grants from Amarin, AstraZeneca, Bristol-Myers Squibb, Eisai, Ethicon, Medtronic, Sanofi-Aventis, and The Medicines Company.
  • Dr. Stone reports consulting for Abbott Vascular, Boston Scientific, and Medtronic.

 

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Disclosures
  • Dr. James reports receiving research grants from Medtronic, Terumo, and Vascular Solutions.

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