Endovascular treatment of abdominal aortic aneurysms with the Powerlink Endograft System: Influence of placement on the bifurcation and use of a proximal extension on early and late outcomes

Infrarenal Aortic Treatment With AFX2 Endograft: Results From a Multicentric, International, Non-Randomized, Prospective Registry-the AFX2-LIVE Study

INTRODUCTION

To confirm real-world clinical practice results reported with anatomically fixed bifurcated endograft, a physician-initiated study was designed-AFX2-LIVE registry.

MATERIALS AND METHODS

From November 2019 to August 2021, investigators enrolled all consecutive patients treated with AFX2 (Endologix Inc., Irvine, CA, USA) endograft. Patients with abdominal aortic aneurysms (AAAs), penetrating aortic ulcers (PAU), and isolated infrarenal aortic dissections were included. Clinical and anatomical data, including baseline, intraoperative, and in-hospital details, as well as follow-up data, were collected in an anonymized prospectively compiled database. The primary endpoint of this study was to evaluate the technical and clinical success of endovascular aortic repair (EVAR) using AFX2 endograft.

RESULTS

A total of 535 patients were enrolled from 43 Italian and Spanish centers and analyzed according to the protocol. Four hundred eighty-nine patients were male (91.4%), with a mean age of 75±8.92 years (range 52-94). Four hundred sixty-six patients (87.1%) were treated for AAA, 49 (9.3%) for PAU, and 20 (3.6%) for isolated abdominal aortic dissection. A proximal extension was needed in 48% of the cases. Assisted technical success was achieved in all but one patient (99.8%). At 30 days follow-up, no AAA-related deaths were recorded, and nine patients (1.6%) required reintervention. At a mean follow-up period of 15.22±13.65 (range 1-53) months, data were available for 479 patients (89.5%). Clinical success was achieved in 98.2% (95% confidence interval [CI]: 96.4-99.1) at 3 months, 93.9% (95% CI: 90.1-96.1) at 1 year, and 74.1% (95% CI: 62.8-82.4) at 4 years follow-up. The estimated freedom from all-cause mortality was 97.7%, 93.4%, 81.6%, 77.5%, and 70.9%, and freedom from AAA-related mortality was 100%, 99.6%, 99.6%, 99.6%, and 97.3% at 3, 12, 24, 36, and 48 months, respectively. Twenty reinterventions (3.7%) were required in 19 patients, of which 3 late open conversions (0.6%) were performed, and 2 AAA-related deaths were observed.

CONCLUSION

This study demonstrated excellent clinical and technical success rates of EVAR with anatomically fixed endografts, providing valuable insights into real-world clinical outcomes.

CLINICAL IMPACT

The AFX2-LIVE study could have a significant impact by providing robust evidence supporting the effectiveness and safety of EVAR using bifurcated endografts with anatomical fixation in real-world clinical practice, ultimately leading to improved outcomes and enhanced patient care in the management of abdominal aortic pathologies.

Unibody bifurcated aortic endograft: device description, review of the literature and future perspectives

The unibody (Powerlink/AFX/AFX2) Endovascular AAA device (Endologix Inc., CA, USA) presents a unique design with its long main body and two innate limbs. The device is designed to be deployed and sits on the native aortoiliac bifurcation and represents the only one-piece bifurcated endograft designed to use anatomical fixation for endograft stabilization. According to published literature, the unibody device seems to represent a valid choice in the treatment of abdominal aortic aneurysms. This particular device would seem to satisfactorily perform even in the treatment of more compressed aneurysms (also in off-label association with parallel grafts) and in occlusive pathologies. Ongoing studies will provide new real-life data in a large and unselected patient population to better understand the device’s advantages and limitations.

Two Decades of Abdominal Aortic Endovascular Repair With the Anatomical FiXation at the Aortic Bifurcation in a Large Single-Center Experience

OBJECTIVE

The introduction of new endograft models improved long-term results of abdominal aortic aneurysm (AAA) endovascular repair (EVAR), but most of them maintained an old and unchanged design: a short body and long legs shifting up the flow divider. This study assessed the long-term results of EVAR with unimodular endoprosthesis fixed at the aorto-iliac bifurcation (Anatomical FiXation), in a large, unselected cohort.

MATERIALS AND METHODS

In a single-center, retrospective cohort study, 623 patients selectively treated between 1999 and 2016, were analyzed. Follow-up protocol included at least a computed tomography angiography within 3 months and a duplex ultrasound and clinical exam yearly. All enrolled patients were analyzed by 2020. The primary outcomes were technical success, clinical success, and survival. Secondary outcomes included survival-free from late-open-conversion (LOC), reintervention, and endoleaks.

RESULTS

Median age was 74±11 years and the follow-up 93±54 months. The technical success was achieved in 99.4% and the 30-day clinical success was 98.4%. A 5-year clinical success of 97.7% was registered and at 10 years success was 96.7%. The overall survival at 1, 5, 10, and 15 years was 92.4%, 79.5%, 64.9%, and 45.5%, respectively. Six (0.98%) AAA-related death were registered, 3 caused by infection of the endograft and 3 for secondary rupture. LOCs were 9 (1.47%) and reintervention-free survival at 1, 5, 10, and 15 years were 88.4%, 78.0%, 76.2%, and 74.6%, respectively. Freedom from endoleaks was 88.8% at 1 year and 72.7% at 15 years. A total of 63 high-flow endoleaks were registered (43 type I, 7 type IIIa, 12 type IIIb, and 1 type Ib+IIIb). No migrations were recorded, and the graft limb thrombosis rate was 1.14%. From a multivariate analysis resulted that long-term clinical success appeared to be reduced in patients affected by diabetes [odds ratio (OR) 0.24; p=0.04] and in presence of calcified and thrombotic iliac accesses (OR 0.16; p=0.006).

CONCLUSION

EVAR with the Anatomical FiXation was confirmed to be safe, feasible, and effective to prevent AAA rupture in the long term as well. However, the overall survival remains afflicted by cardiovascular accident. The original concept of unibody bifurcated design allowed a very low rate of graft thrombosis and zeroed the risk of migration and related reintervention.

Modeling and Computational Comparison of the Displacement Forces Exerted between the AFX Unibody Aortic Stent Graft and its Hybrid Combination with a Nitinol-based Proximal Aortic Cuff

BACKGROUND

The bifurcated AFX (Endologix, Inc, Irvine, CA, USA) aortic stent-graft is the sole unibody endograft for the management of Abdominal Aortic Aneurysms (AAA). In order to improve the AFX central sealing and clinical efficacy in challenging cases, a replacement of the central chromium-cobaltium AFX extension with a Nitinol-based proximal aortic cuff has been suggested. Yet, comparative data regarding the hemodynamic performance of this design is missing. Aim of this study was to compare the displacement forces (DF) acting on the hybrid AFX-Endurant design, with the classic AFX and Endurant endografts, in angulated and non-angulated cases based on patient-specific Computational Fluid Dynamics (CFD) simulations.

METHODS

3D endograft models of 11 treated AAA cases were reconstructed from Computed Tomography Angiography (CTA) imaging data: 5 cases of AFX, 3 cases of the combination AFX-Endurant and 3 cases of the classic Endurant design. The DF on the main-body, the iliac limbs, and the entire stent-graft was calculated by processing the velocity and pressure fields generated by pulsatile CFD simulations.

RESULTS

The range of total DF (acting on the whole endograft structure) in the AFX, hybrid AFX-Endurant and Endurant group was 2.5-5.2N, 2.0-5.9N and 1.9-2.9N respectively, with the maximum total DF being lower for Endurant. The DF on the main-body of the classic and hybrid AFX cases were higher than the right and left iliac limbs (2.5-4.9N vs. 0.6-5.3N and 0.7-3.6N respectively). Conversely, the DF on the main-body of the Endurant cases was comparable to the force exerted on the right and left limbs. When separating the cases with respect to their neck angulation, the DF on all endograft parts (main-body, limbs) and on the endograft as a whole were lower for the hybrid AFX-Endurant group compared to the classic AFX and Endurant groups, for cases with almost straight neck.

CONCLUSION

The off-label use of the hybrid AFX-Endurant stent-graft does not seem superior to the conventional AFX or Endurant endografts in angulated cases but was associated with lower DF than AFX or Endurant in non-angulated cases. The clinical value and utility of these findings remain to be elucidated.

Unibody Endograft Using AFX 2 for Less Invasive and Faster Endovascular Aortic Repair: Protocol for a Multicenter Nonrandomized Study

Background

Since the introduction of endovascular aortic repair (EVAR) for treatment of abdominal aortic aneurysms (AAAs), progressive improvements in results have been achieved. However, conventional bifurcated stent grafts have been proven to have a nonnegligible risk of failure and secondary intervention, principally due to the lack of adequate proximal sealing. The unique AFX 2 Endovascular AAA System (Endologix, Irvine, CA) unibody device, which provides different sealing and fixation features compared with conventional devices, seems to overcome these limitations.

Objective

The aim of this study is to evaluate intraoperative, perioperative, and postoperative results in patients treated with the AFX 2 Endovascular AAA System endografts for elective AAA repair in a large cohort of consecutive patients.

Methods

All eligible EVAR patients will be included in this observational, multicenter, prospective, nonrandomized study. The number of patients to be enrolled is 500.

Results

The primary endpoint of the study is to evaluate the technical and clinical success of EVAR with unibody endografts in short- (90-day), mid- (1-year), and long-term (5-year) follow-up periods. The following secondary endpoints will also be addressed: operative time, intraoperative radiation exposure, contrast medium usage, AAA sac shrinkage at 12-month and 5-year follow-up, and any potential role of patients’ baseline characteristics and device configuration on primary endpoint. The actual start date of the investigation was November 2019. The final patient is expected to be treated by the end of December 2020, and the estimated study completion date is December 2025.

Conclusions

This study will provide verified real-world data on AAAs treated by AFX 2 endografts and followed for a long-term interval.

International Registered Report Identifier (IRRID)

PRR1-10.2196/16959

Management of late main-body aortic endograft component uncoupling and type IIIa endoleak encountered with the Endologix Powerlink and AFX platforms

OBJECTIVE

Junctional component separation producing type IIIa endoleak after endovascular abdominal aortic aneurysm repair (EVAR) is an uncommon but serious complication requiring unanticipated reinterventions. This retrospective study analyzed main-body EVAR component uncoupling and type IIIa endoleaks encountered with Powerlink and AFX (Endologix Inc, Irvine, Calif) endografts during an 8-year period.

METHODS

Type IIIa endoleaks were identified from a database of secondary interventions and clinical surveillance. Operative reports, medical records, and computed tomography studies were reviewed. Clinical and imaging characteristics were analyzed over time, and differences were compared at appropriate follow-up intervals.

RESULTS

Since 2006, 701 patients underwent primary EVAR using Endologix Powerlink (352 patients, 2006-2011) or AFX (349 patients, 2011-2014) endografts. Endoleaks required 32 secondary interventions (4.6%), including type Ia in 4 patients (1 proximal extension and 3 explants); type Ib in 8 patients (all distal extensions for enlarging iliac aneurysms); type II in 1 patient (explant); type IIIa in 17 patients (2.4%), who were the subject of this report; and type IIIb in 2 patients (both EVAR relining). The 17 patients with type IIIa endoleak were an average age of 71 years, and 14 (82%) were men. The mean preoperative abdominal aortic aneurysm (AAA) diameter was 70 ± 18 mm. The repair was elective in 16 patients and an emergency in one. Ten cases were performed with Powerlink and seven with AFX. Analysis of serial computed tomography scans found significant changes in AAA diameter; renal-to-bifurcation straight-line, centerline, and greater curvature lengths; EVAR angulation; and loss of EVAR component overlap. The average time from EVAR to reintervention was 32 months. Three patients returned with a ruptured AAA and three with AAA thrombosis, and three of these patients (18%) died ≤30 days of the emergency reintervention. Secondary procedures included EVAR relining with additional bridging components in 14 patients (82%), explant in 2, and axillobifemoral bypass in 1. No new cases of endograft uncoupling have been identified in patients treated with AFX since December 2012 after adoption of revised instructions for use.

CONCLUSIONS

Although a small number of secondary interventions were needed after EVAR with the Endologix Powerlink or AFX endografts, most were undertaken for late main-body component uncoupling and type IIIa endoleak, which can occur after sideways displacement of the endograft in large and angulated AAAs. Patients treated before 2013 under the old instructions for use should be evaluated for signs of impending component separation and monitored annually, noting that expected indicators of endograft failure, such as increasing AAA diameter and endoleak, may be absent.

Late open conversion after endovascular abdominal aortic aneurysm repair

OBJECTIVE

This study determined the incidence, the surgical details, and the outcome of late open conversion after failed endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm.

METHODS

A review of English-language medical literature from 1991 to 2014 was conducted using the PubMed and EMBASE databases to find all studies involving late conversion after EVAR for abdominal aortic aneurysm. The search identified 26 articles encompassing 641 patients (84% men; median age, 73.5 years).

RESULTS

Mean interval from the initial implantation was 38.5 ± 10.7 months. The cumulative single-center open conversion rate was 3.7%. The indications for late open conversion included endoleak in 62.4%, infection in 9.5%, migration in 5.5%, and thrombosis in 6.7%. Operations were urgent in 22.5% of the patients. The 30-day mortality was 9.1%. Mortality rates were different between elective (3.2%) and nonelective patients (29.2%). Five aneurysm-related deaths (1.5%) and two graft infections (0.6%) occurred during a median follow-up of 26.4 months (range, 5-50.2 months).

CONCLUSIONS

The number of patients with failed EVAR and without further options for endovascular salvage is growing. Endoleak remains the most important weakness of EVAR as the leading cause of late open conversion. Such procedures, although technically demanding, are associated with relatively low mortality rates when performed electively. Open repair still represents a valuable solution for many patients with failed EVAR.

The ‘docking maneuver’ for Gore Excluder positioning in the treatment of abdominal aortic aneurysms with an ectatic neck

The aim was to present a technical modification to the ‘funnel technique’ that allows endovascular repair of infrarenal abdominal aortic aneurysms with an ectatic neck. The body of the Excluder endograft is opened inside the aneurysm, using the slow deployment technique, stopping as soon as the contralateral limb is open. The gate is cannulated in the usual fashion. A percutaneous transluminal angioplasty (PTA) balloon is introduced in the contralateral limb and inflated to nominal pressure. By pulling the introducer of the Excluder delivery system on one side and the PTA balloon on the other, the graft is positioned on the bifurcation with the contralateral leg inside the common iliac artery. At this point, the ipsilateral iliac leg is deployed and the thoracic endograft can be positioned through the abdominal component. Finally, the contralateral iliac leg is deployed. The technique described offers a simple method to treat aortic abdominal aneurysms with an ectatic neck by positioning a bifurcated abdominal graft in such a way that subsequent insertion of the thoracic component is facilitated.

Conversion to open repair after endografting for abdominal aortic aneurysm: a review of causes, incidence, results, and surgical techniques of reconstruction

PURPOSE

To review the incidence, causes, and mortality rates of early and late conversion to open surgery after endovascular aneurysm repair (EVAR) of abdominal aortic aneurysm (AAA).

METHODS

A systematic search of the English-language literature from 2002 to 2009 was performed by interrogation of the PubMed, MEDLINE, and EMBASE databases. Studies were included if they: (1) had >100 patients treated with EVAR and (2) provided adequate data to calculate incidence and associated mortality rates. The search yielded 13 articles with sufficient data to analyze early conversion (12,236 patients, 178 conversions) and 15 articles with available data for late conversion (14,298 patients, 279 conversions).

RESULTS

The rate of early conversion among the 13 articles reviewed ranged from 0.8% to 5.9%; more recent studies carried lower rates of early conversion. Mortality rates of early conversion varied between 0% and 28.5%. Overall, there were 178 (1.5%) early conversions among the 12,236 AAAs treated with EVAR, with an average mortality of 12.4%. The rates of late conversion ranged from 0.4% to 22%. Of the 14,289 AAA patients undergoing endovascular repair, 279 (1.9%) required late conversion; the mortality rate was 10%.

CONCLUSION

Though the incidence is gradually declining, secondary interventions persist as the Achilles' heel of EVAR. A lifelong follow-up strategy for AAA patients treated with EVAR is essential for early detection and treatment of complications of the procedure. Vascular surgeons should be familiar with the complex open conversion procedures.

Thoracic Endograft for Abdominal Aortic Aneurysms, an Unusual Application for Severe Neck Angulation: Case Report and Literature Review

Our goal was to achieve complete proximal sealing in severe aortic neck angulation (SNA) during endovascular aneurysm repair (EVAR) of a patient with an abdominal aortic aneurysm (AAA) unfit for surgery. An 82-year-old patient with an infrarenal AAA of 9.8 cm with an SNA of 90° was admitted for acute coronary syndrome. Following coronary treatment, the patient was considered unfit for surgery and therefore was evaluated for EVAR. Aneurysm sac exclusion was obtained with the deployment of a Powerlink bifurcated graft (Endologix Inc, Irvine, CA) inside a Relay thoracic endograft (Bolton Medical, Florida) placed just below the most distal renal artery. At 6 months, computed tomographic angiography confirmed correct graft placement, complete aneurysm exclusion, and a reduction in the aneurysmal sac. In AAA patients with an SNA at high risk of EVAR failure, the adaptability of a thoracic endograft could be considered for proximal sealing.

Analgesia during abdominal aortic aneurysm endovascular repair: remifentanil vs. fentanyl-midazolam--a randomized controlled trial

BACKGROUND AND OBJECTIVE

Endovascular repair offers a less surgically invasive procedure for abdominal aortic aneurysms but nevertheless, still requires analgesic sedative cover to ensure an acceptable level of patient comfort and cardiorespiratory stability. The peculiarity of this kind of operation is that painful stimuli are concentrated in specific moments separated by intervals devoid of pain, so the insurgence of pain can be predicted and prevented with a bolus of analgesic, making a continuous infusion not essential, but potentially useful in achieving a better analgesic stability. The primary objective of the study was pain control measured by Visual Analogue Scale; secondary endpoints were cardiorespiratory stability and an acceptable level of sedation.

METHODS

The sedative analgesic protocols of two groups of randomly allocated patients, undergoing abdominal aortic aneurysm endovascular repair, were compared. The experimental group received remifentanil infusion (0.03-0.1 microg kg min) and the control group received intravenous doses of fentanyl and midazolam (1-3 microg kg and 0.05-0.1 mg kg, respectively).

RESULTS

Fifty patients were investigated out of 60 enrolled. There were no relevant differences concerning cardiorespiratory stability and level of sedation, but pain levels were significantly lower in the experimental group: mean Visual Analogue Scale 0.35+/-0.40 vs. 1.49+/-0.62 (P<0.001) and area under the curve 17.48+/-5.09 vs. 33.05+/-8.19 (P<0.001).

CONCLUSION

Both techniques were shown to be safe and most importantly effective in offering cardiovascular stability and analgesia for American Society of Anaesthesiologists III-IV patients undergoing endovascular abdominal aortic aneurysm repair. However, remifentanil continuous infusion proved to offer significantly more stable pain control compared with the currently used combination fentanyl-midazolam.