Novel solution for luminal access loss into the double-layered LVIS Blue™ construct

Abstract

We described a novel solution for a challenging case of double-layered LVIS Blue™ (LB) stent construct retraction into a large cavernous aneurysm. The double-layered LB stent construct was used as a flow diverter for treatment of a large cavernous aneurysm. Our solution comprised a balloon angioplasty and placement of balloon-mounted cardiac-stent construct through the side wall of the LB construct, with eventual placement of a Pipeline Flex inside of the final conduit.

Introduction

Among the various types of cerebrovascular lesions, large cavernous aneurysms may present challenge for open surgery and are therefore primarily considered for endovascular treatment. Historically, deconstructive procedures were considered as standard of care, but this has changed in the recent years with the advent of flow diverters (FDs). Using FDs has significantly simplified treatment of these complex lesions, while significantly decreasing associated morbidity and mortality.¹ However, individual anatomical conditions may vary and occasionally, standard techniques may fail. Under such circumstances, alternative and new techniques may have to be employed. This may be associated with yet unknown complication profiles of those newer techniques and paucity of developed ‘bail out’ techniques.

In our example, when standard FD could not be utilized because of failure to open on a curve, double stenting with LVIS Blue™ (LB) stent (MicroVention Inc., Tustin, CA, USA) was utilized as an alternative. This technique has already been described elsewhere, where a double-layered LB stent construct may be used for its flow diversion effect.² Just like with a regular FD (e.g. the Pipeline embolization device (PED), Medtronic, Inc., Irvine, CA, USA) or any other stent, stent retraction into the aneurysm may occur with loss of access to the distal vascular lumen (Figure 2).

Figure 2.

While re-advancing the Headway 21 microcatheter over the delivery system of the second stent, the proximal end of the whole LB stent construct retracted into the aneurysm Thus distal luminal access was lost.

Case description

A 66-year-old right-handed lady presented with a large left cavernous carotid internal carotid artery aneurysm that was increasing in size on follow-up imaging. Given the increasing size of the aneurysm, treatment was recommended. Informed consent was duly obtained.

Intervention

The patient was started on 90 mg of Brilinta (ticagrelor, AstraZeneca, Inc., Wilmington, DE, USA) and 81 mg of Aspirin. Therapeutic level of P2Y12 receptor inhibition (TP2Y12) levels were confirmed on the morning of the intervention. Standard right common femoral artery approach was used and a 6 French (6F) short sheath placed. A diagnostic catheter, in conjunction with a Glidewire® was used to selectively catheterize the left internal carotid artery. A three-dimensional rotational angiography was also performed. We confirmed the presence of a large (21 × 16 × 15 mm) cavernous aneurysm with a 13 mm neck (Figure 1). The patient was fully heparinized. A working angle was determined from the rotational angiogram. Using the standard technique, a 6F long guidesheath was exchanged for the diagnostic catheter. A 0.058" Navien intermediate catheter (ev3/Covidien, Irvine, CA, USA) over a 0.027" Marksman microcatheter (ev3/Covidien, Irvine, CA, USA) was then navigated proximal to the aneurysm over a 0.014" Synchro 2 microwire (Stryker Neurovascular, Fremont, CA, USA). The microwire and microcatheter were navigated distal to the aneurysm. An appropriately sized PED was loaded and advanced to the tip of the microcatheter. The PED and microcatheter were pulled back to the appropriate landing zone distal to the aneurysm. Through a combination of unsheathing and wire advancement, the PED was deployed without success. A second PED device was tried in a similar fashion and also failed to deploy. Next, the Marksman microcatheter was exchanged for a Phenom microcatheter (Medtronic, Irvine, CA, USA). A third PED device was deployed in a similar fashion and failed again.

Figure 1.

A three-dimensional rotational angiography of the left Internal carotid artery confirmed the presence of a large (21 x 16 x 15 mm) cavernous aneurysm.

Next, the decision was made to proceed with creation of a double-layered LB telescoped construct, with the aim of achieving the same flow-diverting effect as with PED.² A Headway 21 (MicroVention, Inc., Tustin, CA, USA) microcatheter was exchanged for the Phenom microcatheter. An appropriately sized LB stent was loaded into the microcatheter and advanced. It was unsheathed from the supraclinoid segment of the ICA through the aneurysm into the petrous ICA. First, the LB was re-accessed with the Headway 21 microcatheter over its delivery system. Second, the LB stent was loaded into the microcatheter and deployed inside the first one. While re-advancing the Headway 21 microcatheter over the delivery system of the second stent, the proximal end of the whole LB stent construct retracted into the aneurysm (Figure 2). Thus, distal luminal access was lost.

Multiple attempts to retrieve the LB construct with a gooseneck snare (Amplatz Goose Neck Microsnare Kit, SK200, eV3, Plymouth, MN, USA) and Mindframe Capture LP stentriever (Mindframe, Irvine, CA, USA) were unsuccessful.

In order to traverse the double-layered LB construct, we used the Duo 167 (MicroVention, Inc., Tustin, CA, USA) microcatheter over a Synchro 2 microwire (Figure 3). Once this was accomplished, the Duo 167 was navigated into the left middle cerebral artery (LMCA) over Synchro 2 microwire. The Synchro 2 was exchanged for a Luge (Boston Scientific, Inc, Natick, Massachusetts, USA) exchange length wire. A 4 mm NC Trek (Abbott Vascular, Santa Clara, CA, USA) balloon was advanced over the Luge wire into the LB construct wall. Angioplasty of the side wall of the LB construct was performed in order to allow advancement of the other stents (Figure 4). Next, three Integrity stents (Medtronic, Minneapolis, MI, USA) (2.75 × 12, 2.74 × 14, and 2.75 × 18 mm) were deployed sequentially, starting from the mid portion of the LB construct, through its sidewall to the proximal petrous ICA (Figure 5). Lastly, a Marksman catheter was advanced over the Luge wire inside the LB–Integrity construct. A 4.5 × 25 mm PED FLEX was deployed inside the stent construct (Figure 6).

Figure 3.

In order to traverse double layered LB construct we used Duo 167 microcatheter over Syncro 2 microwire.

Figure 4.

Balloon angioplasty of the side wall of LB construct was performed in order to allow advancement of the other stents.

Figure 5.

Three Integrity stents were deployed sequentially, starting from the mid portion of LB construct, through its sidewall to the petrous ICA.

Figure 6.

A PED FLEX was deployed inside the stent construct.

In our example, because other techniques failed, the LB stent construct was re-accessed through its two layers of the side wall (Figure 3). Balloon angioplasty was performed and balloon-mounted cardiac stents were sequentially deployed, thus re-establishing connection of the distal LB stent construct with the proximal Internal carotid arteryaartery (ICA) (Figure 5). Finally, PED was deployed inside the cardiac stent montage to achieve flow diversion of the entire aneurysm. This technique resembles a very well-described Y-stenting technique.³ This, to our knowledge, has never been performed through a double-layered LB stent construct in a clinical setting. We believe that this technique should become part of interventionist’s armamentarium as one of the ‘bail out’ options in challenging circumstances.

The patient emerged from the general anesthesia neurologically unchanged.

Discussion

The flow-diversion effect of the double-layered LB stent construct has been well documented.² Using Y-stent configuration has also been well described, using a single-layered LB stent³. This is the first description in the literature to our knowledge of using a cardiac-stent–PED construct through a double-layered LB stent construct.

FD retraction into the aneurysm is a rare, but very challenging complication. Possible ‘bail out’ options may include parent artery sacrifice, which was not an acceptable option in our patient, who had isolated left ICA circulation without a high-flow bypass. Placing such a bypass urgently while being on double antiplatelet medications may be associated with high risks. While reversing antiplatelet medications preoperatively would have subjected the patient to risk of uncontrolled thrombosis of her ICA. Other possible options may include stent retrieval with Snares, stentriever (e.g. Mindframe) or an Alligator device (Chestnut Medical Technologies, Menlo Park, CA, USA). In our case, those options failed. The Alligator device was not available because of the company’s recall.

Although in our example, a successful bail-out strategy was devised as the case progressed, we believe that more attention should be dedicated to developing such types of bail out strategy at bench research and computational modeling levels, utilizing similar approaches to the works cited here of Wang et al.² and Makoyeva et al.³ This is especially important in the field where new tools are being constantly, rapidly and in large number introduced, thus limiting the time for each device to be tested in real-life challenging circumstances.

Conclusion

The successful management of a large cavernous carotid artery aneurysm requires expertise on the part of the neurosurgeon, together with the use of state-of-the-art techniques and equipment. Real-life behavior of complex technology such as that of a complex construct of multiple stents may not be possible to predict accurately. Keeping an open mind and spirit of innovation may contribute to favorable resolution of even unknown or unexpected complications.

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.