American Heart Journal
Volume 160, Issue 2 , Page e9, August 2010

Effectiveness and safety of drug-eluting stents in vein grafts: A meta-analysis

Novara, Italy

Article Outline

 

We read with interest the study by Joyal et al titled “Effectiveness and safety of drug-eluting stents in vein grafts: A meta-analysis.”1 However, there are several methodological drawbacks that flawed the present analysis. First of all, literature research and inclusion process of the observational studies are incomplete for a meta-analysis largely driven by nonrandomized data. In particular, recent observational studies2, 3, 4 with >2000 patients enrolled were not included in the prespecified analysis for observational studies. In addition, selection as an end point of overall “MACEs” is incorrect because of different single clinical outcomes incorporated in MACE definition applied in several trials. Second issue of concern is that internal validity of studies included was not investigated. Meta-analyses of observational studies face the challenge of incorporating studies with various quality levels. Including studies of various quality levels can mask or reverse effect direction.5 The “Newcastle-Ottawa Scale” for assessing quality of nonrandomized studies in meta-analyses is quite comprehensive and has been recommended by the Cochrane Non-Randomized Studies Methods Working Group.6 Third issue is the “publication bias” that was not investigated in the study of Joyal et al; studies with negative results can take longer to be published, and results not conforming to the desired outcome may not even be reported. An investigation of this bias can be performed using a graphical test, such as a funnel plot, which is created by plotting the estimated treatment effect against the study size.7 Finally, significant heterogeneity was found in the analysis of data. However, no effort was made to explain it. Investigation of heterogeneity is a key issue when dealing with observational nonrandomized studies,5 where potential uncontrolled confounders might flaw pooled estimates of the meta-analysis.

Back to Article Outline

References 

  1. Joyal D, Filion KB, Eisenberg MJ. Effectiveness and safety of drug-eluting stents in vein grafts: A meta-analysis. Am Heart J. 2010;159:159–169.e4
  2. Brodie BR, Wilson H, Stuckey T, et al. Outcomes with drug-eluting versus bare-metal stents in saphenous vein graft intervention results from the STENT (Strategic Transcatheter Evaluation of New Therapies) group. JACC Cardiovasc Interv. 2009;2:1105–1112
  3. Goswami NJ, Gaffigan M, Berrio G, et al. Long-term outcomes of drug-eluting stents versus bare-metal stents in saphenous vein graft disease: results from the Prairie “Real World” Stent Registry. Catheter Cardiovasc Interv. 2010;75:93–100
  4. Shishehbor MH, Hawi R, Singh IM, et al. Drug eluting versus bare-metal stents for treating saphenous vein grafts. Am Heart J. 2009;158:637–643
  5. Navarese EP, Lupi A, Buffon A, et al. Meta-analysis of non-randomized studies in interventional cardiology: a critical appraisal. Ital J Pub Health. 2009;6:
  6. In:  Higgins JPT,  Green S editor. Cochrane handbook for systematic reviews of interventions version 5.0.1 [updated September 2008]. The Cochrane Collaboration; 2008;Available at: www.cochrane-handbook.org
  7. Easterbrook PJ, Berlin JA, Gopalan R, et al. Publication bias in clinical research. Lancet. 1991;337:867–872

PII: S0002-8703(10)00433-3

doi:10.1016/j.ahj.2010.05.027

Refers to article:

  • Effectiveness and safety of drug-eluting stents in vein grafts: A meta-analysis

    Dominique Joyal, Kristian B. Filion, Mark J. Eisenberg
    American Heart Journal February 2010 (Vol. 159, Issue 2, Pages 159-169.e4)

American Heart Journal
Volume 160, Issue 2 , Page e9, August 2010

Article Tools