Division of Interventional Cardiology
Hospital Clínico San Carlos
Martín Lagos s/n 28040 Madrid
Spain
E-mail address: raulmorenog{at}terra.es
Unidad de Medicina Preventiva e
Investigacion
Hospital Clínico San Carlos
Martín Lagos, s/n 28040 Madrid
Spain
División of Interventional Cardiology
Hospital Clínico San Carlos
Martín Lagos, s/n 28040 Madrid
Spain
One year ago, we published a meta-analysis demonstrating that coronary stenting is superior to balloon angioplasty with provisional stenting in small coronary arteries.1 We already responded clearly2 to the three criticisms raised by Agostoni et al.3 in a letter to the editor. According to Agostoni et al.,2 one limitation of our meta-analysis is that the primary endpoint was angiographic restenosis.3 We are very surprised about this comment, because angiographic restenosis was the primary endpoint of all the studies included in the meta-analysis.
In the present meta-analysis by Agostoni et al.,3 they have also demonstrated that coronary stenting is a better strategy than balloon angioplasty in small vessels, and we are obviously agreeing with the conclusions. Indeed, their data, including 13 trials, provided a similar odds ratio for restenosis (0.71) compared to our study (0.77). However, their conclusion about the benefit of coronary stenting only when a <20% residual stenosis is obtained after balloon angioplasty is not supported, because of two obvious and serious limitations.
First, in their methods, they used a pre-defined criterion of optimal angioplasty when residual stenosis after balloon angioplasty was <20%. In the trials included in this meta-analysis, this criterion was not pre-defined by the authors, and therefore the authors of the meta-analysis cannot pre-define it post hoc. Instead, the trials included in their meta-analysis defined >30% (Park, ISAR-SMART) or >50% (COAST, BESMART, RAP, SISA, SVS, Kinsara) as cut-off values of residual stenosis after balloon angioplasty as criteria for suboptimal balloon angioplasty. Moreover, provisional stenting has been defined as a coronary stent implantation only in the presence of >35% residual stenosis after balloon angioplasty.4,5
The second limitation is that the authors have not taken into consideration the fact that residual stenosis in the balloon arms in all the trials has been provided in an intention-to-treat analysis, and therefore this residual stenosis is not given by patients treated only with balloon, but also in those in which finally a coronary stent was implanted (cross-over from balloon to stent). Residual stenosis, after having excluded patients with cross-over from balloon to stent, should have been needed to perform such an analysis.
These two limitations invalidate conclusions of the authors supporting provisional stenting in small vessels. We may be tempted to use meta-analytic techniques without profound knowledge of the trials included. Also, in order to avoid improper conclusions, it is very important to respect the criteria and endpoints for which the trials included in the meta-analysis were performed.
References
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