Novel Technique for the Treatment of Type Ia Endoleak After Endovascular Abdominal Aortic Aneurysm Repair

A Single Centre Long Term Follow Up of the Nellix Endovascular Aneurysm Sealing System

OBJECTIVE

To evaluate the clinical performance at long term follow up of endovascular aneurysm sealing (EVAS, Endologix Inc. Nellix, Irvine, CA, USA) in the treatment of abdominal aortic aneurysm (AAA).

METHODS

Observational, prospective, single centre study of primary AAA interventions with EVAS (n = 117) from November 2013 to November 2016. Endpoints were primary technical success, Nellix device failure, freedom from open surgical conversion (OSC), freedom from secondary intervention, sac rupture, total mortality, and aneurysm related mortality at long term follow up.

RESULTS

The median age was 75 years (interquartile range [IQR] 70, 81 years) and 83% were male. The median AAA diameter was 58 mm (IQR 54, 60 mm). The median length of follow up was 6.2 years (IQR 5.6, 6.8 years). Primary technical success was 100%. Median time to Nellix failure was 5.6 years (IQR 3.3, 7.4 years). Freedom from Nellix failure at five and seven years was 54% (95% confidence interval [CI] 54.2 - 63.8%) and 36% (95% CI 22.3 - 49.7%), respectively. Freedom from OSC at five and seven years was 63% (95% CI 53.2 - 72.8%) and 59% (95% CI 47 - 71%), respectively. The secondary intervention rate was 11.4/100 person years. Freedom from secondary intervention at five and seven years was 52% (95% CI 42.2 - 61.8%) and 51% (95% CI 41.2 - 60.8%), respectively. The cumulative mortality rate at five and seven years was 36% and 54%, respectively. Secondary sac rupture occurred in 9.4% (11/117) with a rate of 2/100 person years. Aneurysm related mortality was 12% (14/117) with a rate of 2.5/100 person years. The median survival was four years (IQR 3, 5.6 years). Thirty day mortality for acute OSC was 67% (n = 3) and 17.1% (6/35) for elective OSC.

CONCLUSION

Long term follow up showed an increased failure rate. Diligent surveillance after endovascular AAA treatment is mandatory, especially when promising new devices are put into clinical use.

Combining Endovascular Aneurysm Sealing with Chimney Grafts - 5 Year Follow-Up after 47 Procedures

BACKGROUND

To evaluate longer-term results of a cohort treated with primary chimney endovascular aneurysm sealing (ChEVAS) for complex abdominal aortic aneurysms or secondary ChEVAS after failed endovascular aneurysm repair/endovascular aneurysm sealing.

METHODS

A single-center study was conducted of 47 consecutive patients (mean age 72 ± 8 years, range 50-91; 38 men) treated with ChEVAS from February 2014 to November 2016 and followed through December 2021. The main outcome measures were all-cause mortality (ACM), aneurysm-related mortality, occurrence of secondary complications and conversion to open surgery. Data are presented as the median (interquartile range [IQR]) and absolute range.

RESULTS

35 patients received a primary ChEVAS (=group I) and 12 patients a secondary ChEVAS (=group II). Technical success was 97% (group I) and 92% (group II); 30-day mortality was 3% and 8%, respectively. The median proximal sealing zone length was 20.5 mm (IQR 16, 24; range 10-48) in group I and 26 mm (IQR 17.5, 30; range 8-45) in group II, respectively. During a median time of follow-up of 62 months (range 0-88), ACM amounted to 60% (group I) and 58% (group II); aneurysm mortality was 29% and 8%, respectively. An endoleak was seen in 57% (group I: 15 type Ia endoleaks, four isolated type Ib, and 1 endoleak type V) and 25% (group II: 1 endoleak type Ia, one type II, and 2 type V), aneurysm growth in 40% and 17%, migration in 40% and 17%, resulting in 20% and 25% conversions in group I and II, respectively. Overall a secondary intervention was performed in 51% (group I) and 25% (group II), respectively. The occurrence of complications did not significantly differ between the 2 groups. Neither the number of chimney grafts, nor the thrombus ratio significantly affected the occurrence of abovementioned complications.

CONCLUSIONS

While initially delivering a high technical success rate, ChEVAS fails to provide acceptable longer-term results both in primary and secondary ChEVAS, resulting in high rates of complications, secondary interventions and open conversions.

Editor's Choice - Focused Update on Patients Treated with the Nellix EndoVascular Aneurysm Sealing (EVAS) System from the European Society for Vascular Surgery (ESVS) Abdominal Aortic Aneurysm Clinical Practice Guidelines

OBJECTIVE

After alerts on EndoVascular Aneurysm Seal (EVAS) failure were raised, the European Society for Vascular Surgery (ESVS) Abdominal Aortic Aneurysm (AAA) Clinical Practice Guidelines Writing Committee (WC) initiated a task force with the aim to provide guidance on surveillance and management of patients with implanted EVAS devices.

METHODS

Based on a scoping review of risk for late serious aortic-related adverse events in patients treated with EVAS for AAA, the ESVS AAA Guidelines WC agreed on recommendations graded according to the European Society of Cardiology (ESC) grading system.

RESULTS

EVAS has a very high incidence of late endograft migration resulting in proximal type 1 endoleak with risk of rupture, requiring open conversion with device explantation. The reported mortality rate for elective explantation varies between 0% and 14%, while acute conversion for rupture has a very dismal prognosis with a 67 - 75% mortality rate.

CONCLUSION

It is recommended that all patients in whom a Nellix device has been implanted should be identified, properly informed, and enrolled in enhanced surveillance. If device failure is detected, early elective device explantation should be considered in surgically fit patients.

Engineering In Situ Weldable Vascular Devices

(1) Background: The minimally invasive implantation of medical devices is largely limited by their insertion profile, and, therefore, minimizing them constitutes a leading trend in the field. (2) Methods: This study introduces the in situ welding strategy, whereby the components of the stent grafts used to treat abdominal aortic aneurysms were decoupled, deployed sequentially, and welded together at the aneurysmal site, greatly reducing their insertion profile. Polyurethane elastomers were used to produce the graft and to coat the metallic struts of the stent to render it in vivo weldable. Results: The composition of the polyurethanes was fine-tuned, so to minimize the insertion profiles and optimize the welding properties and the clinical performance of the devices assembled. The stent and graft were deployed successively in pigs via a small 8F introducer, in situ welded, and the patency of the bi-component device was confirmed over a three-month post-implantation period. The strength of the stent/graft welded connection was fully retained, with no de-welding observed. Conclusions: The in situ welding strategy resulted in implantations that were easier to perform and markedly less injurious to tissues and organs, largely expanding the applicability of these ultra-minimally invasive procedures to especially frail segments of the population.

The Dilemma after Sealing an Endovascular Aortic Aneurysm - Three Ways Out

INTRODUCTION

Endovascular aneurysm sealing (EVAS) was commercially introduced in 2013. The initial results of EVAS were positive, leading to its widespread use. The mid- and long-term reports showed greater than expected rates of migration, which led to a recall of the device. In the present article, we describe our experience in managing type Ia endoleaks and migration occurring with the Nellix system in three different ways: open repair with Nellix explantation, Nellix-in-Nellix application (NINA technique), and the use of the multibranched Colt device originally dedicated to the treatment of thoracoabdominal aneurysms.

MATERIALS AND METHODS

From February 2014 to June 2021, we performed 20 procedures for failed EVAS or ChEVAS (migration, type Ia endoleak, secondary aneurysm rupture). All patients treated for EVAS failure were male, aged 65 - 79.

RESULTS

Seven Nellix explantations were performed. Three patients were admitted to our hospital with ruptured aneurysms that occurred 3 weeks to 4 years (mean 124 weeks) after EVAS, and another four with type Ia endoleak. In all but one case, removal of the Nellix system was easy. In two patients, tube grafts were implanted and in the remaining five cases, bifurcated grafts were implanted. In four patients, graft legs were anastomosed with the internal iliac arteries. One patient with secondary aneurysm rupture died from multiorgan failure on the 4th postoperative day. In two cases, transient renal failure was noticed in the perioperative period. All patients were admitted to the intensive care unit for 1 to 4 days (mean 2 days). The mean hospital stay was 9 days. All patients stayed in follow-up (3 - 56 months), but no other complications occurred. Eight patients were treated with the NINA technique: five for distal migration of the Nellix and three for failed ChEVAS. Four patients had a NINA procedure performed with three chimneys, three with two and one with one chimney. In one case, two iliac limbs were implanted to avoid kinking of the external iliac arteries. The median hospitalization time after the procedure was 9 days (range 3 - 12). Four patients developed transient acute renal insufficiency in the perioperative period. The follow-up ranged between 4 and 72 months. In one patient, deterioration of preexisting chronic renal insufficiency developed 5 months after the procedure, but dialysis was not required. One patient died from exacerbation of heart failure 7 months after the NINA procedure. The Colt device was implanted in five patients for the treatment of distal migration with type Ia endoleaks. None of the patients developed any signs of spinal cord ischemia. All patients were admitted to the intensive care unit for 1 or 2 days. In two cases, transient acute renal failure was noticed in the perioperative period. The mean hospital stay was 9 days. All patients remained in follow-up (6 - 22 months). In one case, the occlusion of the celiac trunk branch was found in contrast computed tomography 1 month after implantation of the Colt device, but without any symptoms. No other complications occurred.

CONCLUSIONS

Normal strategies for the management of complications for late failure of EVAR, including stent-graft extensions, are not suitable after EVAS; therefore, alternatives are necessary. Conversion to open repair carries an extensive burden on the patient, so it is not recommended for patients with high surgical risk. The use of a Nellix-in-Nellix application to treat late failure of EVAS is not within the instructions for use but could be an effective strategy for a type Ia endoleak with or without migration. The use of this technique has been extremely limited since the Nellix system was recalled from the market. The use of the Colt multibranched device may be an alternative option, but due to the small number of patients, this method needs further evaluation.