Old Technique, New Use: Novel Use of a Buddy Wire to Deploy
a Detached Stent

Case Report

A 72-year-old female with a non-ST-elevation myocardial infarction and 10 years post-coronary artery bypass surgery presented to our hospital. She had a left internal thoracic artery (LITA) anastomosed to her left anterior descending (LAD) artery, and reverse saphenous vein grafts (SVG) to her diagonal and obtuse marginal (OM) vessels in 1996. She subsequently underwent bare-metal stent implantation in her mid-right coronary artery and in the ostium of her vein graft to the OM in 2004. Coronary angiography revealed that the LAD was occluded and the circumflex and bifurcating OM1 had severe proximal stenosis (Figure 1). The right coronary artery and the LITA to the LAD were widely patent. Both saphenous vein grafts to the diagonal and OM were occluded at their origins. Thus, the only reasonable target for intervention appeared to be the native circumflex and OM1 vessels.
The left main artery was engaged with a GL3.5 Viking^® (Guidant Corp., Indianapolis, Indiana) 6 Fr guiding catheter, and a Pilot 50™ (Guidant) wire was passed into the distal OM1. A 2.0 x 20 mm balloon was used to predilate the severe stenosis in the OM and circumflex artery. A localized dissection was visualized post-balloon inflation (Figure 2). Next, several attempts to pass a 2.5 x 24 mm, 2.5 x 12 mm Liberté™ (Boston Scientific Corp., Natick, Massachusetts) and 2.5 x 12 mm Mini-Vision^® (Guidant) stents failed. The 2.0 x 20 mm balloon was therefore used to dilate the proximal circumflex at high pressures to provide a larger lumen for the stents. Unfortunately, the 2.5 x 12 mm Liberté and 2.5 x 8 mm Mini-Vision stents again failed to cross the proximal circumflex artery. An Extra-Sport™ (Guidant) buddy wire was introduced into the circumflex vessel for support, and a 2.5 x 8 mm Mini-Vision stent again failed to cross the proximal circumflex. Upon attempting to withdraw this stent, there was resistance and the balloon became detached from the stent. It was noted that the detached stent was immobile in the proximal circumflex artery (Figure 3). The primary Pilot 50 wire was left in place through the detached stent. At this point, we attempted to pass a second Pilot 50 wire around the stent and were successful in doing this, however, a 1.5 x 11 mm Mercury^® balloon (Abbott Laboratories, Abbott Park, Illinois) would not cross around the stent over the wire. Snaring and other retrieval techniques with braiding were not acceptable options in our opinion, since this would cause us to lose wire access to the already dissected distal vessel, and we suspected that rewiring this would be extremely difficult. Next, we attempted to pass an ACE™ 2.0 x 20 mm fixed-wire, low-profile balloon (Boston Scientific) around the stent so as to crush it, however, although the wire would cross, the balloon component would not. Our next thought was to try to deploy the stent in its current position. We therefore tried several times unsuccessfully to pass a 1.5 x 11 Mercury balloon over the original wire through the detached stent. We then used an Extra-Sport wire, and after about 20 minutes, we were able to pass this second wire through the center of the detached stent and distally through the dissected segment; this was done while leaving the primary Pilot 50 wire in place, also through the center of the detached stent. Therefore at this point, there were 2 wires in the central lumen of the detached unexpanded stent. Another attempt at passing the 1.5 x 11 Mercury balloon now over this second wire was easily achieved, and it was inflated to 18 atm (Figure 4). Next, a 2.0 x 20 mm balloon was passed again easily over the Extra-Sport wire and was inflated at 12 atm. A Zoom cine angiogram was taken to ensure deployment of the Vision stent, demonstrating expansion of the entire Vision stent (Guidant) (Figure 5). The stent was then upsized with a 2.5 x 12 Maverick^® balloon (Boston Scientific), which then allowed us to pass 2.5 x 8 and 2.5 x 12 Mini-Vision stents beyond the first (now deployed) stent to thoroughly cover the dissected segment. Finally, a 2.75 x 12 Vision stent was inflated in the ostial circumflex and distal left main and postdilated with a 3.25 x 8 mm Quantum balloon (Boston Scientific). A good result was obtained, with TIMI 3 flow and no residual dissection (Figure 6). The patient was free of limiting angina, reinfarction or rehospitalization at 1 month postprocedure.

Discussion

Stent dislodgement from its balloon catheter is a difficult scenario and still occurs in today’s delivery systems. Several successful retrieval techniques exist, however, most entail losing the primary wire as access to the vessel. In cases of stent loss and vessel dissection, this may not be an optimal strategy. The stent-crush technique may be a viable method to deal with this in small-caliber and calcified vessels, however, this is often not possible. If techniques exist to deploy detached stents at the site of loss (if the stent size-to-vessel caliber ratio is reasonably matched), this may represent a reasonable alternative to retrieval in difficult cases. In our patient, with a distal dissection and a dislodged stent, we preferred to utilize a stent-crush or deployment technique rather than a retrieval technique with subsequent loss of the primary wire. After several failed attempts to balloon-crush the lost stent, we attempted to deploy it. We presume, due to the altered architecture of the proximal stent struts that were grated against calcified vessel tissue during the withdrawal attempt, that we were not able to pass a small, low-profile balloon through the detached stent over the primary wire. We therefore used the technique of “buddy wiring”, often utilized in tortuous or calcified native vessels to aid in passing balloons and stents. We managed to pass a second wire through the center of our lost stent, and were subsequently able to pass a small balloon and then deploy the stent with successively larger balloons, thereby salvaging the lost stent and completing the procedure. This technique of utilizing a buddy wire through the center of a lost stent to aid in deploying a detached stent has never been described previously in the literature.
It is possible that the second wire entered the stent in a different orientation and angle, thereby enabling passage of the balloon, which had been unsuccessful several times previous to this. The use of an Extra-Sport may have offered some benefits. The soft tip enhances steerability through stent struts, while its larger core diameter and Teflon coating may enhance deliverability of balloons and stents through the detached stent, as well as providing a vessel-straightening effect. In other situations, a partial stent crush technique may also be a possibility for deploying a detached stent if the second wire goes in through a proximal side strut and then through the center lumen of the detached stent.
One limitation of our approach is the assumption that the stent is detached at a site in the vessel where it can be deployed with reasonable stent apposition to the vessel wall. The passage of a second wire through the center of an undeployed stent can also be a technically challenging procedure and requires meticulous wiring. Our case demonstrates that the well-known technique of “buddy wiring” can be successfully applied in a completely new scenario of detached stent deployment.

References

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