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Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet].

Meta-analysis comparing the effect of drug-eluting versus bare metal stents on risk of acute myocardial infarction during follow-up

R Moreno, C Fernandez, L Calvo, A Sanchez-Recalde, G Galeote, R Sanchez-Aquino, F Alfonso, C Macaya, and JL Lopez-Sendon.

Review published: 2007.

CRD summary

This review concluded that, compared with bare-metal stents, the use of drug-eluting stents was associated with a significant decrease in angiographic restenosis, resulting in a decrease in subsequent revascularisations and incidences of myocardial infarction during the 12 months' follow-up after stent implantation. In view of the limited reporting of review methods, the conclusion should be interpreted with caution.

Authors' objectives

To determine whether drug-eluting stents (DES) decrease the incidence of myocardial infarction (MI) at midterm follow-up.

Searching

MEDLINE and abstract supplements of major scientific meetings of the European Society of Cardiology, American College of Cardiology, American Heart Association and Transcatheter Cardiovascular Therapeutics were searched until January 2006.

Study selection

Study designs of evaluations included in the review

Randomised controlled trials (RCTs) were eligible for inclusion.

Specific interventions included in the review

Studies of coronary stents commercially available in Europe by February 2006 were eligible for inclusion. The DES included in the review were Cypher, Taxus, Endeavor, Janus, Xience V and Axxon.

Participants included in the review

Inclusion criteria were not specified in terms of the participants. The participants in the included trials had been treated with either DES or bare metal stents (BMS). The mean age of the participants ranged from 59 to 67 years. The proportion of women ranged from 12 to 37%. The proportion of participants diagnosed with diabetes mellitus ranged from 2 to 100%. Where reported, the reference vessel diameter ranged from 2.20 to 3.32 mm and the minimum lumen diameter from 0 to 1.27 mm.

Outcomes assessed in the review

Inclusion criteria were not specified in terms of the outcomes. The outcomes assessed in the included studies were major adverse cardiac events, death, target lesion revascularisations, restenosis, stent thrombosis, incidence of acute MI, and incidence of Q-wave and non-Q-wave acute MI (AMI). The definition of AMI in most trials was a new increase in serum creatinine kinase of at least twice the upper limit of the normal reference range, with a concomitant increase in the MB fraction of the enzyme (Q-wave or non-Q-wave infarction depending on the development of new Q waves on the electrocardiogram). In most trials perioprocedural infarction was included in the cumulative incidence of AMI during follow-up. Follow-up ranged from 6 to 12 months.

How were decisions on the relevance of primary studies made?

The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.

Assessment of study quality

The authors did not state that they assessed validity.

Data extraction

The authors did not state how the data were extracted for the review, or how many reviewers performed the data extraction.

Odds ratios (ORs) for AMI and 95% confidence intervals (CIs) were calculated by comparing DES and BMS rates using raw data for each study; intention-to-treat data were used.

Methods of synthesis

How were the studies combined?

The studies were pooled using DerSimonian and Laird random- effects, Peto or fixed-effect models according to tests for heterogeneity. The results were presented in forest plots.

How were differences between studies investigated?

Statistical heterogeneity was using the Q test and the I-squared statistic.

Results of the review

Twenty-five RCTs (n=9,791) were included in the review.

The risk of AMI was significantly lower in patients allocated to DES than those allocated to BMS: 3.3% versus 4.2% (OR 0.79, 95% CI: 0.64, 0.97, p=0.03; based on 22 trials); there was a relative risk decrease of 21% in the risk of AMI (95% CI: 3, 36). There was no evidence of statistical heterogeneity between the trials.

The OR was 0.69 (95% CI: 0.49, 0.97) in trials evaluating DES containing sirolimus, 0.88 (95% CI: 0.66, 1.18) in trials evaluating DES containing paclitaxel, and 0.78 (95% CI: 0.44, 1.40) in trials evaluating DES containing other drugs.

When 19 trials were pooled, the rate of Q-wave AMI did not differ in patients allocated to DES and those allocated to BMS: 0.7% versus 0.6% (OR 1.20, 95% CI: 0.65, 2.20, p=0.56). The risk of non-Q-wave infarction was 2.7% in patients allocated to DES compared with 3.4% in those allocated to BMS (OR 0.79, 95% CI: 0.60, 1.05, p=0.11; 16 trials).

Authors' conclusions

A significant decrease in angiographic restenosis associated with the use of DES leads not only to a decrease in the need for subsequent revascularisation procedures but also to a decreased incidence of MI during the first 12 months of follow-up after stent implantation.

CRD commentary

The inclusion criteria were defined in terms of the intervention and study design, but not in terms of the participants or outcomes. The search strategy was limited to one electronic database and abstracts of scientific meetings, thus it is possible that pertinent studies have been missed. Since it was unclear whether language restrictions had been applied and all studies were published in English, it is unclear whether language bias has been introduced into the review. The methods used to select the studies and extract the data were not reported, so it is difficult to comment on the risk that bias and errors have been introduced during the review process. The included studies were restricted to RCTs but, since the quality of these studies was not formally assessed, the results from these studies and any synthesis might not be reliable.

The methods used to combine the studies seem appropriate and statistical heterogeneity was assessed, but only a few outcomes were formally synthesised. The authors noted the limitation of the short follow-up of 12 months or less. As the quality of the included studies and the methods used to conduct the review were not reported, overall, it is difficult to comment on the strength of the evidence underpinning the authors' conclusions. These conclusions must therefore be regarded with caution.

Implications of the review for practice and research

The authors did not state any implications for practice or further research.

Bibliographic details

Moreno R, Fernandez C, Calvo L, Sanchez-Recalde A, Galeote G, Sanchez-Aquino R, Alfonso F, Macaya C, Lopez-Sendon J L. Meta-analysis comparing the effect of drug-eluting versus bare metal stents on risk of acute myocardial infarction during follow-up. American Journal of Cardiology 2007; 99(5): 621-625. [PubMed: 17317360]

Indexing Status

Subject indexing assigned by NLM

MeSH

Equipment Design; Follow-Up Studies; Humans; Immunosuppressive Agents /administration & dosage; Myocardial Infarction /etiology; Randomized Controlled Trials as Topic; Risk Assessment; Stents

AccessionNumber

12007001255

Database entry date

16/05/2008

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.

CRD has determined that this article meets the DARE scientific quality criteria for a systematic review.

Copyright © 2014 University of York.

PMID: 17317360

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