Author + information
- William Nicholson, MD∗ ()
- ↵∗Reprint requests and correspondence:
Dr. William Nicholson, York Hospital, Department of Cardiology, 1001 S. George Street, York, Pennsylvania 17403.
The technical approach to bifurcation lesions in percutaneous coronary intervention consists of a complex array of potential strategies. Although an upfront 2-stent strategy may be applicable in some cases, the predominant approach is to stent the main vessel (MV) and provisionally treat the side branch (SB). With this approach, many operators prefer to wire both the MV and the SB, leaving the SB wire in position while stenting the MV. This obligates the SB wire to being jailed behind the MV proximal stent struts. In the case of SB occlusion after MV stenting, the jailed wire may create a more favorable angle and serve as a target for the operator to advance a new guidewire into the SB for intervention. For years, it has remained a subject of controversy as to what wire design should be used for the initial SB wiring and jailing. Operator concern has mainly been balanced between the fear of a non–polymer-jacketed wire getting stuck and potentially fracturing versus the anxiety of shearing off the polymer coating in a jacketed wire. In this issue of JACC: Cardiovascular Interventions, Pan et al. (1) provide us with an elegant study that provides an answer to this question and should largely put this discussion to rest.
The investigators present a well-designed prospective study in which 235 consecutive patients undergoing bifurcation stenting were randomized to initial wiring of the SB vessel with either a polymer-covered or non–polymer-covered wire. After MV stenting, the SB wires were removed and underwent microscopic analysis to evaluate for evidence of damage to both the external cover and inner spring coils surrounding the wire core. The primary endpoint of resistance to damage of the jailed wire was overwhelmingly in favor of the polymer-covered wires. Only 2 of 114 polymer-coated wires sustained any microscopic damage, and in both cases the damage was classified as mild. This is juxtaposed with the observation that nearly one-half (49%) of the non–polymer-coated wires were damaged to at least some degree, with 2 having severe damage to the inner spring coils, exposing the wire core. Although no complete wire fractures were observed in the study, the investigators make a reasonable assertion that the increased severity of damage observed would be a surrogate marker in the continuum leading to fracture.
Nearly every high-volume complex percutaneous coronary intervention operator has either had the misfortune of experiencing a wire fracture or has assisted in attempting to remedy the situation for a colleague who has. The question posed to the interventional community following this study is “Why would I ever again jail a non–polymer-coated wire?” At first glance, the answer seems obvious that the theoretical concern of shearing off the polymer coating is dramatically outweighed by the occurrence, now shown to be common, of significant non–polymer-covered wire damage. Although the binary outcome of finding very rare microscopic damage to a polymer-covered jailed wire likely mitigates the immediate intraprocedural dreaded and potentially disastrous complication of wire fracture, there may be more than meets the stereoscopic microscopic eye.
Chatterjee et al. (2) performed electron microscopic evaluation of 20 polymer-covered guidewires used for SB protection during bifurcation stenting and found that 80% of the wires displayed some degree of polymer shearing. It is likely that polymer-covered shearing does in fact frequently occur but cannot be appreciated unless the wire is subjected to more intense scrutiny with an electron microscope. Although one may dismiss this finding because of its lack of translation to immediate adverse procedural sequelae, leaving behind microscopic residual polymer in the distal coronary bed may be of clinical consequence. Grundeken et al. (3) looked at autopsied hearts in patients who had undergone coronary stenting. Histological samples from the myocardial territory of the stented coronary vessel showed the presence of foreign material identified as embolized hydrophilic coating in 10% of the cases. This occurred in cases in which the polymer-coated wire was not even subjected to the stress of having been jailed. Interventionalists should take some solace in the fact that although there is likely microscopic shearing and embolization of hydrophilic coating in many cases, the present study did not show any difference in the secondary outcomes of periprocedural acute myocardial infarction and major adverse cardiac events after a mean follow-up period of 29 months.
Guidewire design and iteration is a complex field that has led to tremendous improvements in procedural success and efficiency. Interventionalists become passionate about their workhorse wire choices and preferences, but a thorough understanding of wire design is often deficient. In controversial topics such as that addressed in this study, it is important to have intimate knowledge of the equipment. This disconnect between what one understands about the wire being used and its actual true design is exemplified by the fact that many physicians who subscribed to the notion that trapping a polymer-covered wire was ill advised have likely been doing so unwittingly. Figure 1 demonstrates the basics of wire design. If an operator has previously subscribed to the notion that a polymer-covered wire should not be jailed, and chose a BMW Universal for this application, it should be recognized that only the distal 45 mm of this wire is not covered. In effect, operators making this choice have been jailing a polymer-covered wire all along.
Although I will certainly continue to follow future studies to see whether microscopic embolization of polymer material translates to adverse clinical events, my primary attention is focused on the procedure I am undertaking today. The investigators should be commended on a well-executed and valuable contribution to the interventional community, and from this point on, my practice will be to jail only polymer-covered wires.
↵∗ Editorials published in JACC: Cardiovascular Interventions reflect the views of the authors and do not necessarily represent the views of JACC: Cardiovascular Interventions or the American College of Cardiology.
Dr. Nicholson has reported that he has no relationships relevant to the contents of this paper to disclose.
- American College of Cardiology Foundation
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