A nonstandard custom-made device to treat a type IA endoleak 6 years after Nellix implantation

Abstract

The Nellix graft has been withdrawn from the market for the early graft failures associated with sac enlargement and rupture. To manage this complication, open conversion has been described as the main solution. However, we report the case of an 85-year-old female patient admitted with a type IA endoleak on a Nellix graft, with 70-mm aneurysmal sac, and treated with a custom-made device manufactured by Cook, to fit the peculiar graft conformation and patient’s anatomy. In this case, accurate prosthesis design and surgical planning were essential to complete the procedure with no intraoperative complications.

Endovascular aneurysm sealing (EVAS) using the Nellix System (Endologix) was introduced with the aim of reducing the incidence of type II endoleaks and reinterventions after conventional endovascular aneurysm repair.^1,2

This endoprosthesis was constructed on the concept of abdominal aortic aneurysm (AAA) sac sealing, with two polymer-filled endobags, covering balloon-expandable stents.

EVAS has been demonstrated to undergo severe adverse events, as previously reported,^3,4 and failures were identified in almost one-half of the interventions, with the appearance of type IA endoleaks, sac growth, and rupture.⁵

Graft explantation is the most frequent surgery used for correction of type IA endoleaks after EVAS, although the development of new technologies provides a good alternative for the treatment of elderly patients with several comorbidities. We report the case of a type IA endoleak repair on a Nellix device in an octogenarian patient, using a custom-made fenestrated device with a peculiar design.

Case report

An 85-year-old female patient was admitted to the vascular surgery unit with a type IA endoleak, detected on a routine follow-up computed tomography angiography (CTA). The patient underwent EVAS using the Nellix System 6 years before, for a 55-mm infrarenal AAA. In her medical history, she reported arterial hypertension, dyslipidemia, atrial fibrillation and severe chronic obstructive pulmonary disease. At the last CTA, a type IA endoleak was detected with neck evolution and development of a juxtarenal AAA, loss of the proximal graft sealing, distal stents migration, and an sac diameter increase that had reached 70 mm (Fig 1). Nevertheless, a preocclusive stenosis at the origin of the superior mesenteric artery (SMA) was enhanced.

Fig 1.

Three-dimensional volume rendering preoperative computed tomography angiography (CTA), showing the Nellix stent migration and the type IA endoleak.

Considering her age and comorbidities, the patient was judged unfit for open surgery, so endovascular treatment was deemed the best option. In consideration of the Nellix conformation and the patient’s anatomy, with a distance to the neo-aortic bifurcation from the lowest renal artery of 41 mm and an inner aortic diameter of 19 mm, a custom-made device (CMD) manufactured by Cook (Cook Medical) was planned, with special characteristics: a proximal diameter of 32 mm and a distal diameter of 12 mm, designed to end directly inside the endoprosthesis stent; four fenestrations for the revascularization of the visceral vessels, with a dedicated pre-cannulation system for the left renal artery (RA) and SMA; and a 2-cm branch dedicated to the revascularization of the other Nellix branch. Imaging measurements were obtained using the multiplanar reconstruction feature of OsiriX software and verified by the Cook Planning Center. Nevertheless, this CMD was designed to fit inside a 20 Fr sheath (Fig 2), and the manufacturing time was 4 weeks.

Fig 2.

Custom-made device (CMD) design with four fenestrations for the visceral vessels, the precannulation system, and a branch for the left iliac stent.

The surgery was performed via bilateral percutaneous transfemoral and right humeral accesses. In the first instance, a balloon-expandable covered stent VBX 7 × 29 mm (W L. Gore) was placed in the SMA to treat the stenosis and to allow a better catheterization. The right humeral access was needed to use the pre-cannulation system to facilitate the SMA cannulation. After ballooning of the entire right stent using a 12-mm Mustang (Boston Scientific), the prosthesis was inserted and released using a partial-deploy technique. Then, using the pre-cannulation system, the fenestrations for left RA, right RA, SMA, and then celiac trunk were sequentially cannulated (Fig 3), and after complete graft release, VBX ballon-expandable stents were chosen and placed in the visceral vessels.

Fig 3.

Intraoperative fluoroscopy, after custom-made device (CMD) partial release, shows renal arteries (RAs) and superior mesenteric artery (SMA) cannulation.

The left branch was then revascularized using a Cook ZISL 11-59 from a dedicated branch of the CMD to the left Nellix stent. At the end of the procedure, the aneurysm was completely excluded, and the visceral vessels were well-visualized (Fig 4). The patient was discharged home within 5 postoperative days without complications. The 30-day postoperative CTA showed the graft and visceral vessels patency, with complete sac exclusion (Fig 5).

Fig 4.

Completion angiography at the end of the procedure.

Fig 5.

Three-dimensional volume rendering reconstruction at the 30-day postoperative reconstruction.

The patient was then enrolled in the standard follow-up protocol for complex aortic procedures, including a 6-month and 12-month duplex ultrasound and 1-year CTA. The patient signed a written informed consent for CMD implantation in an approved device use and the publication of the present case report, imaging included.

Discussion

The treatment of type IA endoleak following endovascular aneurysm repair included several options: from the open conversion to the endovascular relining.^6,7

EVAS using the Nellix system has demonstrated to undergo major adverse events, with failures in almost one-half of the implants, due to type IA endoleaks with subsequent sac growth and rupture.⁸ To treat these cases, initially the use of a Nellix-in-Nellix device presented favorable initial results; however, this strategy is no longer applicable⁹ because the device has been withdrawn from the market.¹⁰

In peculiar conditions, such as an unusually short distance between the lowest RA and the aorto-iliac bifurcation, Mesnard et al have described the possibility of an innovative one-piece custom-made bifurcated fenestrated stent graft.¹¹

Proximal extension using the chimney technique has been studied, but according to guidelines, the use of parallel graft techniques should only be considered as an option in the emergency setting or as a bailout.¹²

Physician-modified endovascular grafts are nowadays gaining more space^13,14 due to their adaptability to different configuration and the absence of manufacturing time. However, the presence of a high neo-bifurcation, as well as the great distance between the visceral vessels and RAs origin, did not make this a viable option for this case. Nevertheless, for the legal implication, we prefer to choose this option only in urgent or emergent cases.

Then the patient was judged unfit for surgical repair,¹⁵ and the possibility of designing a CMD within 4 weeks was deemed the best solution. In our country, in fact, CMDs are available upon physician request and hospital financial approval. However, the use of these devices is subject to regional regulatory approvals and may not be available in all countries. In this context, a peculiar geometry was studied to achieve the best result in this complex anatomy. The distal diameter was chosen of 12 mm to allow the distal landing zone inside the previously implanted Nellix stent graft. The necessity to revascularize the left stent was achieved designing a 2-cm outer branch with the diameter of 10 mm. The fenestrations were designed with a dedicated pre-cannulation system, due to the narrow visceral aorta.

Lastly, all these features were designed to be inserted in a low-profile 20 Fr sheath, to easily access inside the chromo-cobalt 10 mm Nellix stent, and to secure the possibility of crossing this stent, a pre-dilatation with a 12 mm balloon was performed before the CMD insertion.

Nevertheless, we prefer the right upper extremity access, because it gives more comfort to the surgeon, exposure to less radiation, and can be faster.¹⁶

In this case, the prosthesis design and surgical planning were essential to secure the procedural success and avoid complications.

The long-term durability of this geometry should be evaluated in longer term follow-up CTAs to confirm the promising postoperative findings.

Conclusions

In the case presented, we report the efficacy and feasibility of a peculiar CMD in the presence of a Nellix graft. In this case, particular attention should be paid to the design and to the preoperative planning to avoid complications.

Funding

None.

Disclosures

None.