LETTERS TO THE EDITOR
Coronary stenting versus balloon angioplasty in small vessels
Pierfrancesco Agostoni, MD*,
Giuseppe G.L. Biondi-Zoccai, MD and
Antonio Abbate, MD
* Catheterization Laboratory, Section of Cardiology, Department of Biomedical and Surgical Sciences, University of Verona, Piazzale A. Stefani 1, 37126 Verona, Italy
(Email: agostonipf{at}genie.it).
We read with interest the study by Moreno et al. (1), which demonstrated, through a
meta-analytic technique, the significant reduction of restenosis due to stent in
comparison to percutaneous transluminal coronary angioplasty in small-vessel coronary
artery disease. However, the investigators failed to emphasize that substantial statistical
heterogeneity was present, as shown in their overall analysis in Figure 1 (p for
heterogeneity = 0.019).
We believe that this constitutes a methodological flaw in the study. Indeed, substantial
heterogeneity is considered by several investigators to be a contraindication to quantitative pooling
analysis (2), although other authorities recommend the need for summary measures for
the best estimate of the impact of an intervention, albeit that correct methodological
techniques are used to investigate the differences among single trials (3).
Furthermore, Moreno et al. (1) tried to assess, by means of linear regression analysis, the
possible association of several angiographic variables with the benefit of stents,
finding a significant inverse relationship between reference vessel diameter (RVD) and the risk reduction of angiographic restenosis after stent placement with respect to balloon angioplasty (i.e., the smaller the vessel, the larger the benefit of stenting). However, we believe the correct methodological tool to address whether a covariable may
have a significant effect on the outcome in a meta-analysis is meta-regression (4).
Using this technique (which weights each study according to its statistical weight [i.e.,
the inverse of the variance]) to analyze the very same data presented in their study, we
did not find any significant relation between RVD and risk reduction of angiographic
restenosis after stent placement.
Moreover, another recent trial, published only as an abstract (5), did not confirm the
investigators' hypothesis. Indeed, in front of the smallest mean RVD of all the trials on small-vessel
disease (2.17 mm), there was a nonsignificantly increased risk of restenosis (relative
risk 1.14 [95% confidence interval 0.89 to 1.48]) after stenting.
Finally, meta-analytic techniques allow quantitative assessment of treatment effects from pooled
data. With the widening of their use and because of potential errors, improper analyses
may result in misleading conclusions; thus, optimal methodological procedures should
be utilized to validate findings.
 |
References
|
|---|
1. Moreno R, Fernandez C, Alfonso F, et al. Coronary stenting versus balloon angioplasty in small vesselsA meta-analysis from 11 randomized trials. J Am Coll Cardiol 2004;43:1964-1972.[Abstract/Free Full Text]
2. Petitti DB. Meta-Analysis, Decision Analysis and Cost-Effectiveness Analysis: Methods for Quantitative Synthesis in Medicine2nd ed.. New York, NY: Oxford University Press; 2000.
3. Lau J, Ioannidis JP, Schmid CH. Summing up the evidence: one answer is not always enough Lancet 1998;351:123-127.[CrossRef][Web of Science][Medline]
4. Thompson SG, Higgins JP. How should meta-regression analyses be undertaken and interpreted? Stat Med 2002;21:1559-1573.[CrossRef][Web of Science][Medline]
5. Hausleiter J, Kastrati A, Mehilli J, et al. A randomized trial comparing phosphorylcholine-coated stents with balloon angioplasty in small coronary arteries in patients with symptomatic coronary artery diseaseThe ISAR–SMART-2 trial (abstr). Circulation 2003;108(Suppl IV):IV569.
This article has been cited by other articles:
|
|
|
|
 
P. Agostoni, G. G.L. Biondi-Zoccai, G. L. Gasparini, M. Anselmi, G. Morando, M. Turri, A. Abbate, E. P. McFadden, C. Vassanelli, P. Zardini, et al.
Coronary stenting in small vessels: reply
Eur. Heart J.,
August 1, 2005;
26(15):
1562 - 1563.
[Full Text]
[PDF]
|
|
|
|
|
|
|
P. Agostoni, G. G.L. Biondi-Zoccai, G. L. Gasparini, M. Anselmi, G. Morando, M. Turri, A. Abbate, E. P. McFadden, C. Vassanelli, P. Zardini, et al.
Is bare-metal stenting superior to balloon angioplasty for small vessel coronary artery disease? Evidence from a meta-analysis of randomized trials
Eur. Heart J.,
May 1, 2005;
26(9):
881 - 889.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
Top
References