Department of Cardiology
Isala Klinieken
Locatie Weezenlanden
Groot Wezenland 20
8011 JW Zwolle
The Netherlands
Tel: +31 38 4242198
Fax: +31 38 4243222
E-mail address: v.r.c.derks{at}isala.nl
Department of Cardiology
Isala Klinieken
Locatie Weezenlanden
Groot Wezenland 20
8011 JW Zwolle
The Netherlands
Department of Cardiology
Isala Klinieken
Locatie Weezenlanden
Groot Wezenland 20, 8011 JW Zwolle
The Netherlands
Department of Cardiology
Isala Klinieken
Locatie Weezenlanden
Groot Wezenland 20
8011 JW Zwolle
The Netherlands
With great interest, we read the paper by Gyöngyösi et al.1 who describe the results of the ReoPro-BRIDGING trial. However, we feel that the study results should be interpreted with caution. The primary endpoint is the corrected TIMI frame count (CTFC) of the infarct related vessel (IRV) at initial angiography. However, the limitation of CTFC is that it can only be measured in patients with TIMI 2 flow or more, as the dye will not reach the distal landmark in patients with TIMI 0 or 1 flow. At initial angiography, 5070% of patients will have TIMI 0 or 1 flow of the IRV, despite the pre-treatment with aspirin, heparin, and a glycoprotein 2b/3a blocker. Therefore, in the sample-size calculation, one should correct for the 5070% of patients in whom the primary endpoint cannot be assessed.
We also have concern about the assumption that CTFC would be a median of 16.1 frames higher in the intervention group when compared with the control group, on the basis of the difference in CTFC in patients treated with thrombolytic therapy and in healthy controls. First of all, the median CTFC values in either the abciximab or the control group were much higher than the values of patients after thrombolytic therapy (39.1) or healthy controls (23). Secondly, by using the comparison of lytic treated patients vs. healthy controls, one assumes that after pre-treatment with abciximab, 100% of IRV's have normal restoration of flow. This is highly optimistic and far from daily life experience.
In addition, no referral is made to other randomized controlled trials with the same design and 2b/3a blocker used, which did not show a difference in the initial TIMI flow.2,3 In these studies, the rate of initial TIMI 3 flow in the control or placebo arm was considerably higher than the 7% found in the ReoPro-BRIDGING study. If only one patient in the placebo arm would have been scored as TIMI 3 flow, instead of TIMI 2 flow, the difference would no longer be statistically significant (P=0.11).
Therefore, the results of the study should be interpreted with caution, as the study is underpowered to detect a difference in the primary endpoint, especially due to the fact that the primary endpoint could be assessed in <50% of the study population.
References
|