Balloon sandwich technique for retrieval of fractured delivery wire of pipeline stent

Abstract

Delivery wire fracture of flow-diverter stents are rare but have been described. We describe a video case of a successful technique to retrieve such a fractured delivery wire by using a balloon microcatheter and the intermediate catheter when other proven methods may fail.

Introduction

The use of flow-diverter stents for the treatment of cerebral aneurysms is on the rise given the long-term durability and favorable occlusion rates with relatively low complication rate.¹ There have been a few observational multicenter studies demonstrating the efficacy and safety of flow-diverter stents for small intracranial aneurysms.^2,3 Flow-diverter stents provide higher occlusion and lower retreatment rates without any significant increase in morbidity or mortality in patients with intracranial aneurysms <10 mm.⁴ It was also seen that treatment with flow-diverter stents was cost-effective compared with stent-assisted coiling.⁵ The caveat is that most of these studies are retrospective or observational and a randomized study would be beneficial to truly establish which treatment modality is better. In USA, currently the only food and drug administration (FDA) approved flow diverter is the pipeline flex (Medtronic, Minneapolis, MN, USA). The deployment of the pipeline flex stent in the intracranial circulation across the aneurysm is potentially more challenging than simply unsheathing (unlike other aneurysm-bridging self-expanding stents.) There is a learning curve to the deployment process and includes a fair bit of pushing and pulling the delivery wire or the entire system.⁶ The stent and its delivery system are designed to sustain the torque and tension during this pulling and pushing of the stent but inadvertent complications may occur during this process. Wire fracture of the pipeline stent delivery system is a rare complication but has been previously reported.⁷ We present a video case of fractured delivery wire during pipeline flex stent deployment that we were unable to retrieve with the usual retrieval devices and eventually used a balloon technique to successfully retrieve the wire.

Clinical case

A 57-year-old female was incidentally found to have bilateral ophthalmic aneurysms with the left side measuring approximately 7 mm and right side approximately 4 mm in orthogonal diameter (Figure 1(a)). She underwent successful pipeline flex stent embolization of the left aneurysm. We then proceeded to treat the right ophthalmic aneurysm with a pipeline flex stent. Our usual set up for pipeline stent delivery is a tri-axial system comprising of a 6F shuttle guide catheter, a 0.058 inch Navien intermediate catheter (Medtronic, Minneapolis, MN, USA) and a 0.027 inch Marksman microcatheter (Medtronic). The patient was adequately pretreated with aspirin and clopidogrel for the procedure. After deployment of the pipeline stent (3.0 mm × 18 mm), we attempted to re-sheath the delivery wire. To re-sheath the delivery wire, we advanced the microcatheter gently over the delivery wire while maintaining mild tension on the delivery wire. We were successful in capturing the proximal markers and the entire length of core wire under the device but as we neared the distal marker the wire fractured proximal to the proximal marker (Figure 1(b) and (c)). Once we realized the wire had fractured inside the microcatheter, we attempted to retrieve the fractured wire by manipulating the intermediate or microcatheter, but were unsuccessful (Figure 1(d) and (e); see video). We then removed the microcatheter and attempted to use a gooseneck snare device through the intermediate catheter but were unsuccessful in securing the wire (Figure 1(f)). Subsequently we used a 4 mm × 10 mm Hyperglide balloon microcatheter (Medtronic) and navigated it through to the distal end of the intermediate catheter. We inflated the balloon and sandwiched the fractured wire between the inflated balloon and the intermediate catheter and the entire system was pulled out successfully (Figure 1(g) and (h)). The pipeline stent was well opposed to the vessel wall but during the manipulation, the pipeline stent migrated down and did not adequately cover the distal aneurysm neck, so we successfully placed another telescoping pipeline flex stent (3.25 mm × 18 mm) that completely covered the prior stent as well as the aneurysm with good stagnation of contrast in the aneurysm (Figure 1(i) and (j)). No thrombus formation on the stent or delivery wire was noted and the patient had normal neurological exam post procedure. Angiographic follow up at 6 months demonstrated complete occlusion of aneurysm.

Figure 1.

(a) DSA, lateral view, showing the pre-treatment broad based ophthalmic aneurysm. (b) Post pipeline stent deployment DSA, lateral view, showing the distal tip of the delivery wire (short arrow) in relation to the aneurysm. The microcatheter (arrow head) and intermediate catheter (long arrow) are seen. (c) Unsubtracted DSA showing the outline of the pipeline stent (white arrow) with the distal tip of the delivery wire at the distal end of the stent (small arrow). Microcatheter (arrow head) and intermediate catheter (long arrow). (d and e) Unsubtracted DSA, lateral view, after the fracture of the wire, proximal to the proximal marker (short arrow), manipulation of the microcatheter (long arrow) was unable to free the wire tip off the stent. Resheathing marker (arrow head). (f) Unsubtracted DSA, oblique view, the microcatheter is removed and through the intermediate catheter the lasso (white arrow) of the snare is advanced to the vicinity of the proximal marker (black arrow) and resheathing marker (arrow head). (g) Unsubtracted DSA, lateral view, a balloon catheter (long arrow) is advanced distal to the proximal marker (arrow head) through the intermediate catheter (short arrow). (h) Unsubtracted DSA, lateral view, with the balloon catheter inflated (long arrow) the delivery wire is sandwiched against the intermediate catheter lumen (short arrow). Proximal markers (double arrows). Pipeline stent (arrow head). (i) Unsubtracted DSA, lateral view, overlapping pipeline stent (double arrow) placed to ensure complete coverage of the aneurysm. (j) DSA delayed run, lateral view, stagnation of contrast seen in the aneurysm (arrow) post overlapping pipeline placement.

DSA: digital subtraction angiography.

Discussion

Fracture of the delivery wire of pipeline stent is rare based on few reported cases in literature, but interestingly most cases involved the posterior circulation aneurysms.^7–10 Amongst the reported cases the most common cause of wire fracture is the lead wire being stuck in a perforator. In one case, the authors fractured the delivery wire on purpose by torqueing, since they were not able to free the lead wire stuck in the perforator.¹¹ In two cases the delivery wire was abandoned in the intracranial circulation and fortunately the patients did not suffer any late neurological complications. In the fourth case, the delivery wire was retrieved using a microsnare.⁸ Most of these cases (3/4) were also associated with thrombus formation over the stent/wire and required use of abciximab.^7,8,11 The balloon sandwich technique has been previously described in the interventional cardiology and peripheral vasculature literature with good success.^9,12 The advantage of this technique for pipeline stent fractured wire primarily depended on the use of a tri-axial system, as we were able to recognize the fracture while the distal tip remained in the intermediate catheter, and then opposed the fractured wire between the balloon and the intermediate catheter. After reviewing the angiogram, we speculate that the distal end of the lead wire was caught into the distal tines of the stent that caused it to fracture during the resheathing process (see video). Although we hope that most pipeline deployments are uneventful, wire fracture complications do occur and this balloon sandwich technique may be a useful to keep in one’s armamentarium to retrieve the fractured wire.

Declaration of conflicting interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.