CORRESPONDENCE: LETTER TO THE EDITOR
Reply
Francesco Burzotta, MD, PhD,
Filippo Crea, MD, FACC and
Leonarda Galiuto, MD, PhD*
* Institute of Cardiology, Catholic University of the Sacred Heart, Policlinico A. Gemelli, Largo A. Gemelli, 8, 00168 Rome, Italy (Email: lgaliuto{at}rm.unicatt.it).
Drs. M.I. and S.G. Worthley provide comments on the results of our recently published substudy of the REMEDIA (Randomized Evaluation of the Effect of Mechanical Reduction of Distal Embolization by Thrombus-Aspiration in Primary and Rescue Angioplasty) trial (1). To date, various small-to-medium-sized prospective randomized trials have been performed testing the efficacy of thrombectomy and/or distal protection in patients with ST-segment elevation acute myocardial infarction (STEMI) (2). The overall results have to be considered conflicting and inconclusive. Differences in the device used (never tested in a head-to-head randomized trial), study populations, and reperfusion marker are expected to play a major role in determining such heterogeneous findings. The role of the clinical characteristics of the study population has been documented in the subgroup analysis of the REMEDIA trial showing that the benefit of thrombus-aspiration in myocardial reperfusion was observed only in patients with persistently occluded culprit artery after guidewire crossing and/or with a higher thrombus burden (3) and confirmed by the subgroup analysis of the AIMI (Angiojet Rheolytic Thrombectomy in Patients Undergoing Primary Angioplasty for Acute Myocardial Infarction) trial showing a strong trend toward reduction in final infarct size only in patients with angiographically visible thrombus treated by rheolytic thrombectomy (4). Similarly, the neutral findings of the PROMISE (Protection Devices in PCI Treatment of Myocardial Infarction for Salvage of Endangered Myocardium) study must be interpreted with caution as the study population included a heterogeneous variety of both STEMI and non-STEMI patients (5).
As for the influence of reperfusion marker in the results, if we move from the widely available and easy-to-assess markers of reperfusion (blush and ST-segment resolution) to more sophisticated evaluations of microvascular function/integrity, the number of patients necessary to observe an effect is significantly lower. The number of patients studied in the REMEDIA contrast echo substudy fitted our power calculation (1). Nevertheless, the observed findings of our study are original and interesting as they suggest that microvascular obstruction as evaluated after 24 h and at follow-up is significantly reduced by thrombus-aspiration; conversely, they question the effect of thrombus-aspiration on left ventricular remodelling, possibly because several factors other than microembolization influence remodelling (1).
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References
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- Galiuto L, Garramone B, Burzotta F, et al. Thrombus aspiration reduces microvascular obstruction after primary coronary intervention: a myocardial contrast echocardiography substudy of the REMEDIA trial J Am Coll Cardiol 2006;48:1355-1360.[Abstract/Free Full Text]
- Burzotta F, Testa L, Giannico F, et al. Adjunctive devices in primary or rescue PCI: a meta-analysis of randomized trials Int J Cardiol 2007In press.
- Burzotta F, Trani C, Romagnoli E, et al. Manual thrombus-aspiration improves myocardial reperfusion: the randomized evaluation of the effect of mechanical reduction of distal embolization by thrombus-aspiration in primary and rescue angioplasty (REMEDIA) trial J Am Coll Cardiol 2005;46:371-376.[Abstract/Free Full Text]
- Ali A, Cox D, Dib N, et al. AIMI Investigators Rheolytic thrombectomy with percutaneous coronary intervention for infarct size reduction in acute myocardial infarction: 30-day results from a multicenter randomized study J Am Coll Cardiol 2006;48:244-252.[Abstract/Free Full Text]
- Gick M, Jander N, Bestehorn HP, et al. Randomized evaluation of the effects of filter-based distal protection on myocardial perfusion and infarct size after primary percutaneous catheter intervention in myocardial infarction with and without ST-segment elevation Circulation 2005;112:1462-1469.[Abstract/Free Full Text]
Related Article
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Is Thrombus Aspiration the Appropriate "Remedy"?
- Matthew I. Worthley and Stephen G. Worthley
J. Am. Coll. Cardiol. 2007 49: 1670.
[Full Text]
[PDF]
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References