CORRESPONDENCE: LETTER TO THE EDITOR
Reply
Pedro Silva-Orrego, MD*,
Paola Colombo, MD, PhD and
Riccardo Bigi, MD
* Niguarda Hospital, via Bizzoni 5, Milan, 20125, Italy (Email: pedrosilva{at}tiscali.it).
We appreciated the comments by Dr. Napodano and colleagues and would like to address their concern. The DEAR-MI (Dethrombosis to Enhance Acute Reperfusion in Myocardial Infarction) study (1) included consecutive randomization of acute myocardial infarction (AMI) patients fulfilling the inclusion criteria regardless of angiographic evidence of thrombus based on the assumption that thrombus is always present in AMI. Compared with angioscopy, the presence of intracoronary thrombus is significantly underestimated by angiography (2). In our randomized population, 73% of controls and 81% of patients undergoing aspiration showed an occluded vessel with Thrombolysis In Myocardial Infarction (TIMI) flow grade 0/1 at the initial angiogram, which is a good indicator of the presence of thrombus. Macroscopic thrombus retrieval was observed in 95% of patients undergoing aspiration; moreover, at the multivariate analysis, thrombus removal, but not the presence of occluded vessel, was predictive of myocardial reperfusion. Thus, our results cannot be ascribed to differences in thrombus burden, in our opinion.
The low prevalence of TIMI flow grade 3 in both groups seems to depend on the rigid lecture method we applied rather than a poor epicardial reperfusion, as demonstrated by the very favorable corrected TIMI frame count representing a more objective measure of epicardial flow.
We also acknowledge that the rate of myocardial blush (MBG) grade 2 + 3 observed in the control group of our study is higher than previously reported (3,4). However, both stenting and glycoprotein IIb/IIIa inhibitors were not consecutively used in previous studies; in addition, patients with previous infarction, or by pass-grafting, and cardiogenic shock were not included in our study. In any event, the difference between MBG grades 2 and 3, representing the key point of the issue, was significantly more favorable among patients undergoing aspiration.
Finally, the ischemic time was similar in the 2 groups of our study. Therefore, although we are aware of the importance of this variable in achieving a good reperfusion, we do not believe it affected the results of our study.
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References
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- Silva-Orrego P, Colombo P, Bigi R, et al. Thrombus aspiration before primary angioplasty improves myocardial reperfusion in acute myocardial infarction: the DEAR-MI study J Am Coll Cardiol 2006;48:1552-1559.[Abstract/Free Full Text]
- White CJ, Ramee SR, Collins TJ, et al. Coronary thrombi increase PTCA risk Circulation 1996;93:253-258.[Abstract/Free Full Text]
- van’t Hof AWJ, Liem A, Suryapranata H, Horntje JCA, de Boer MJ, Zijlstra F, Zwolle Myocardial Infarction Study Group Angiographic assessment of myocardial reperfusion in patients treated with primary angioplasty for acute myocardial infarction: myocardial blush grade Circulation 1998;97:2302-2306.[Abstract/Free Full Text]
- Sorajja P, Gersh BJ, Costantini C, et al. Combined prognostic utility of ST-segment recovery and myocardial blush after primary percutaneous coronary intervention in acute myocardial infarction Eur Heart J 2005;26:667-674.[Abstract/Free Full Text]
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