Editor’s Note: This case highlights the difficulties encountered in stent retrieval. As interventionalists, we all need to be familiar with the use of snares and peripheral catheters and sheaths, which are essential for stent retrieval (still on the guidewire or embolized). Large-bore sheaths from the contralateral approach may help to remove the frayed dislodged stents. Also, plaque modification of calcified lesions is essential for proper stent delivery and expansion. — Samin K. Sharma, MD, Mount Sinai Medical Center, New York, New York
Attempting stent delivery to calcified and/or tortuous coronary lesions is associated with increased procedural complications. Unsuccessful stent delivery to the target lesion has been associated with both micro and macroscopic damage to the stent structure.1,2 Partial deployment or fraying of the stent may hinder recapture into the guiding catheter. Vigorous attempts to recapture the stent may result in complete dislodgment of the stent from the balloon, leading to stent loss. Coronary stent loss is a rare but potentially catastrophic complication of percutaneous coronary intervention (PCI). The occurrence of stent loss during PCI is associated with higher rates of bleeding, myocardial infarction, emergency coronary artery bypass grafting and death.3 A variety of treatment strategies for “salvage” after stent dislodgment have been described, including in situ deployment, retrieval and crushing of the stent with another stent.4,5 In the following case, we describe a case of unsuccessful delivery of a coronary stent complicated by deformation of the proximal stent edge rendering the stent unable to be retrieved through the guiding catheter. Intravascular removal of the stent from the balloon with subsequent use of a peripheral vascular crossover sheath to snare the frayed stent is described.
Case Report. An 82-year-old male with a history of hypertension presented with rest angina and transient ST-segment elevation in his anterior precordial electrocardiographic (ECG) leads. Coronary angiography demonstrated a hazy 95% stenosis of the proximal left anterior descending (LAD) coronary artery with heavy calcification and a mid-LAD that was also heavily calcified and tortuous with a long 80% stenosis (Figure 1). In addition, the patient had a focal 80% lesion in his first obtuse marginal coronary artery and a non-dominant right coronary artery. Given the rest symptoms and ECG findings, intervention was undertaken for the LAD. A 6 French (Fr) guiding catheter was used to engage the left main from the right femoral approach. The patient had been loaded with aspirin and was treated during the procedure with intravenous heparin and eptifibitide. The mid and proximal LAD lesions were initially dilated with a 2.0 mm diameter compliant balloon, followed by a 2.5 mm diameter non-compliant balloon to 12 atm. The lesions that were dilated appeared to yield and a 2.5 x 20 mm Xience everolimus-eluting stent (Abbott Vascular, Abbott Park, Illinois) was advanced into the LAD. The stent was advanced to the midpoint of the LAD tortuosity, but attempts to advance the stent to cover the mid LAD lesion were unsuccessful, despite the use of a “buddy wire” for support. The decision was made to remove the stent from the coronary vessel and consider additional predilation. However, once in the left main, the stent would not re-enter the guiding catheter upon withdrawal. Given TIMI 3 flow in the LAD with no apparent dissection, the guiding catheter, stent delivery system, and coronary wire were pulled back as one unit into the right common femoral artery. Under fluoroscopy, the proximal stent edge appeared frayed and had taken on a “trumpet-like” appearance (Figure 2). Initially, attempts were made to remove the stent system from the ipsilateral femoral approach. The guide catheter was first pulled into the 6 Fr femoral sheath. The stent-balloon system was then pulled back to the tip of the sheath; however, similar to the guiding catheter, the frayed stent would not pass through the tip of the 6 Fr femoral sheath. At this point, given the lack of apparent deformation of the distal stent edge, the decision was made to try a contralateral retrieval technique. An 8 Fr sheath was placed in the left femoral artery and an exchange-length, extra-support Terumo glidewire (Terumo Medical, Somerset, New Jersey) was advanced into the right external iliac artery using a 5 Fr Soft-Vu Omni Flush catheter (AngioDynamics, Latham, New York) for support. The Omni Flush catheter and the short 8 Fr sheath were exchanged out for an 8 Fr Ansel modification peripheral sheath (Flexor Check-Flo Introducer, Cook Incorporated, Bloomington, Indiana). In preparation for retrieval, the stent was removed from its balloon by gently pulling it down against the tip of the right femoral sheath, thus stripping off the undeployed stent. Great care was taken to ensure that it remained on the wire. The balloon catheter and guide were completely removed from the patient. A 4 mm diameter, 120 cm Amplatz Gooseneck snare device (ev3, Plymouth, Minnesota) was introduced through the Ansel sheath and advanced into the right femoral artery. The coronary wire in the right femoral artery was advanced by a second operator to meet the snare. After 2 attempts, the coronary wire was successfully snared and the snare was “walked down” the wire to the stent (Figure 3). The stent was then snared in its mid body and externalized from the patient through the Ansel sheath (Figure 4). Repeat coronary angiography was performed, and revealed continued TIMI 3 flow in the LAD. The patient was chest-pain free and given the severe calcification and tortuosity of the mid LAD, further PCI was not attempted. The patient underwent successful two-vessel coronary artery bypass grafting 24 hours later.
Discussion. This case provides an excellent example of the perils associated with stent delivery in calcified arteries, particularly when there is superimposed vessel tortuosity. It is likely that the proximal stent edge became frayed during attempts to withdraw the stent back through a highly calcific vessel. Damage to undelivered stents has been described previously and appears to disrupt the polymer coating.2 Although this process can occur with any stent, we speculate that thinner strut-cell designs may be more prone to mechanical disruption of the stent structure.
The inability to recapture the stent system into the guiding catheter can be particularly vexing and highlights one of the advantages of large-diameter guides when treating calcified vessels. Deformation of the proximal stent edge (as opposed to the distal edge) is particularly difficult to manage as even partial re-entry into the guiding catheter is often not possible. Numerous issues related to retrieval of frayed stents warrant mention. First, in the present case, the coronary guidewire and guiding catheter were removed from the LAD without adverse consequences. If maintenance of wire access is needed, obtaining radial arterial access and re-wiring the coronary vessel is a reasonable approach. Removal of the stent system away from the left main and aortic arch was felt to be important in this case to prevent embolization of the stent into a “high-risk” circulation (carotids). Secondly, it is also important to note that upsizing the 6 Fr femoral sheath to an 8 Fr sheath (or larger) with an 0.35 inch diameter guidewire for support is not possible when there is a coronary wire in the femoral vessel and certainly not while there is a stent-balloon system in place. The limitation in this situation is that an 8 Fr femoral sheath dilator will not accommodate both a 0.35 inch diameter guidewire and a 0.014 inch diameter coronary guidewire. One could attempt to place a sheath without a dilator, particularly in a thin patient, although kinking of the sheath and potential damage to the femoral artery are important limitations. Theoretically, using an oversized coronary balloon to dilate the tip of the femoral sheath is an option to allow passage of the frayed stent — though the authors have not attempted this. Lastly, contralateral access and placement of a large-diameter crossover peripheral sheath is a useful technique, as highlighted by this case. Hussain et al have also previously described use of the crossover technique to retrieve a detached coronary embolic protection filter and embolized stent from the contralateral femoral artery.1 Maintenance of the embolized stent on its guidewire is important in reducing the effort required for successful snaring. Advancement of the guidewire to meet the snare and then advancement of the snare down the wire is a useful technique in this particular situation.Conclusion. This case reinforces the concept of adequate lesion predilation and use of rotational atherectomy whenever possible for calcified lesions. Aggressive attempts to deliver stents to such lesions can lead to stent deformation. When fraying of stent struts does occur, familiarity with snares and the peripheral crossover technique are important skills for successful retrieval.
- Hussain F, Rusnak B, Tam J. Retrieval of a detached partially expanded stent using the SpideRX and EnSnare devices — First report. J Invasive Cardiol 2008;20:E44–E47.
- Kitahara H, Kobayashi Y, Yamaguchi M, et al. Damage to polymer of undelivered sirolimus-eluting stents. J Invasive Cardiol 2008;20:130–133.
- Brilakis ES, Best PJ, Elesber AA, et al. Incidence, retrieval methods, and outcomes of stent loss during percutaneous coronary intervention: A large single-center experience. Catheter Cardiovasc Interv 2005;66:333–340.
- Bolte J, Neumann U, Pfafferott C, et al. Incidence, management, and outcome of stent loss during intracoronary stenting. Am J Cardiol 2001;88:565–567.
- Satler LF. Incidence, retrieval method, and outcomes of stent loss in percutaneous coronary intervention: A large, single-center experience. Catheter Cardiovasc Interv 2005;66:341–342.