Author + information
- Nick E.J. West, MD, MA⁎ ( )(, )
- Stephen P. Hoole, MA, DM and
- Liam McCormick, MBBS
- ↵⁎Department of Interventional Cardiology, Papworth Hospital, Papworth Everard, Cambridge CB23 3RE, United Kingdom
We read with interest the 15-month follow-up of the DEDICATION (Drug Elution and Distal Protection in Acute Myocardial Infarction) trial reported by Kaltoft et al. (1). The authors find that, in patients undergoing primary percutaneous coronary intervention (pPCI) randomized to receive distal protection (DP) with embolic filter devices, the rates of stent thrombosis and both clinically driven target lesion revascularization (TLR) and target vessel revascularization (TVR) were significantly higher than in patients randomized to standard pPCI. This finding is perhaps not so surprising when the physical characteristics of the devices used and recognized complications of their use are considered.
The majority of DP devices used in the trial were FilterWire EZ devices (Boston Scientific, Natick, Massachusetts), whereas a smaller proportion of patients in the study received the SpiderX device (eV3 Inc., Minneapolis, Minnesota); this device has the advantage of being available in a variety of different sizes that may be tailored to the patient's particular coronary anatomy. The FilterWire EZ, however, is available in only 1 size, designed for vessel reference diameters between 3.5 and 5.5 mm. The median vessel diameter and the diameter of stent deployed in the patients receiving DP devices were 3.5 mm, implying therefore that a substantial proportion of patients receiving such devices had native vessel reference diameters smaller than the minimum vessel size designated for the FilterWire EZ.
Furthermore, even when appropriately sized, the FilterWire EZ has been demonstrated to cause histological evidence of substantial intimal disruption (2), and simple extrapolation might indicate that an oversized device may lead to deeper medial injury similar to that observed in experimental models of deliberate vascular injury leading to predictably observed restenosis (3).
Therefore, the findings of the study in terms of the increased rates of restenosis that presumably led to observed higher rates of TLR and TVR (1) may be explained by the utility of devices oversized for target vessel pPCI. Further analysis of the differences in TLR/TVR rates in patients receiving the different types of devices would therefore be informative and, although numbers in the study may be relatively small, might further inform the debate as to whether DP devices should be barred outright in pPCI, or alternatively that appropriately sized DP devices may still have some utility.
- American College of Cardiology Foundation
- Kaltoft A.,
- Kelbaek H.,
- Klovgaard L.,
- et al.
- Lindner V.,
- Fingerle J.,
- Reidy M.A.