Computational prediction of proximal sealing in endovascular abdominal aortic aneurysm repair with unfavorable necks

BACKGROUND AND OBJECTIVE

Endovascular aortic aneurysm repair (EVAR) has become the standard treatment for abdominal aortic aneurysms in most centers. However, proximal sealing complications leading to endoleaks and migrations sometimes occur, particularly in unfavorable aortic anatomies and are strongly dependent on biomechanical interactions between the aortic wall and the endograft. The objective of the present work is to develop and validate a computational patient-specific model that can accurately predict these complications.

METHODS

Based on pre-operative CT-scans, we developed finite element models of the aorta of 10 patients who underwent endovascular aortic aneurysm repair, 7 with standard morphologies and 3 with unfavorable anatomies. We simulated the deployment of stent grafts in each aorta by solving mechanical equilibrium with a virtual shell method. Eventually we compared the actual stent ring positions from post-operative computed-tomography-scans with the predicted simulated positions.

RESULTS

A successful deployment simulation could be performed for each patient. Relative radial, transverse and longitudinal deviations were 6.3 ± 4.4%, 2.5 ± 0.9 mm and 1.4 ± 1.1 mm, respectively.

CONCLUSIONS

The numerical model predicted accurately stent-graft positions in the aortic neck of 10 patients, even in complex anatomies. This shows the potential of computer simulation to anticipate possible proximal endoleak complications before EVAR interventions.

Long-Term Outcomes Following Transarterial Embolisation of Proximal Type I Endoleaks Post-EVAR

PURPOSE

To describe the long-term outcomes following transarterial embolisation for type Ia endoleaks (ELIa) in patients who failed or were unsuitable for standard endovascular/surgical options.

MATERIALS AND METHODS

A retrospective single-centre observational study was performed between October 2010 and April 2018. Technical success rates and long-term outcomes were evaluated. A sub-analysis was performed comparing outcomes of covered aortic endografts and Nellix endovascular aneurysm sealing systems.

RESULTS

A total of 34 transcatheter embolisations were performed for ELIa in 27 patients (13 endografts and 14 patients with Nellix systems). A combination of Onyx and coils was used most frequently (18/34), followed by Onyx alone (14/34) and coils alone (2/34). Technical success was achieved in 33/34 (97%) procedures . Seven early complications occurred with no immediate mortality, 5 of which involved migration/reflux of embolic into the endograft-all successfully managed via endovascular approach. Following the surveillance period (mean 25 months), 13/26 (50%) of patients were free from recurrent endoleak. Sac expansion occurred in 42% (11/26). 21/26 patients died; 6 due to aneurysm sac rupture, 10 due to unrelated causes, and 5 had no cause of death available. No significant difference in survival was found between patients with an endograft or Nellix graft-Chi-squared value - 0.011 (p < 0.05 = 3.84).

CONCLUSIONS

Transcatheter embolisation for type Ia endoleaks is a safe and effective option in a select patient cohort-where traditional endovascular and surgical options are unsuitable or have failed. The procedure may prevent recurrence in some whilst delaying rupture and death in others.

Multicentre experience with an iliac fenestrated device

OBJECTIVES

The aim of this study was to present a multicentre experience of technical results and mid-term follow-up using a custom-made iliac fenestrated device (Terumo Aortic, Inchinnan, Renfrewshire, UK) for the treatment of iliac aneurysms and endoleaks.

METHODS

A multicentre retrospective evaluation of 22 patients (3-12 per institution) with either an iliac artery aneurysm or endoleak treated with an iliac fenestrated device was performed. Data were gathered from 3 departments of vascular and endovascular surgery at 3 European institutions.

RESULTS

Ten of the included patients (45.5%) were treated for an endoleak and 12 had aorto-iliac aneurysms (54.5%). Two patients underwent bilateral fenestrated device implantation for a total of 24 devices included in this analysis. Primary technical success was 91.7% (22 of 24 implanted devices). One of the 24 internal iliac arteries could not be cannulated and was covered (primary assisted technical success rate 95.8%) and 1 patient required a relining of the stent graft due to a mid-grade stenosis opposite the internal iliac artery fenestration. Survival at the last available follow-up (mean 15.2 ± 12.0 months, range 0.5-36.6 months) was 90.9%.

CONCLUSIONS

The present investigation adds to a growing body of literature on custom-made endografts and their usefulness in achieving endovascular repair without compromising blood flow via important arterial branch vessels, such as the internal iliac artery. It presents encouraging technical and mid-term follow-up data from consecutive patients treated for iliac aneurysms or endoleaks using this custom-made device. The technique may help avoid adverse sequelae associated to a coil-and-cover approach when iliac branch devices are not feasible.

Systematic review of embolization of type I endoleaks using liquid embolic agents

OBJECTIVE

The long-term success of endovascular aneurysm repair (EVAR) is limited by complications, most importantly endoleaks. In case of (persistent) type I endoleak (T1EL), secondary intervention is indicated to prevent secondary aneurysm rupture. Different treatment options are suggested for T1ELs, such as endo anchors, (fenestrated) cuffs, embolization, or open conversion. Currently, the treatment of T1EL with liquid embolic agents is available; however, results are not yet addressed. This review presents the safety and efficacy of embolization with liquid embolic agents for treatment of T1ELs after EVAR.

METHODS

A systematic literature search was performed for all studies reporting the use of liquid embolic agents as monotherapy for treatment of T1ELs after EVAR. Patient numbers, technical success (successful delivery of liquid embolics in the T1EL) and clinical success (absence of aneurysm related death, endoleak recurrence or additional interventions during follow-up) were examined.

RESULTS

Of 1604 articles, 10 studies met the selection criteria, including 194 patients treated with liquid embolics; 73.2% of the patients were male with a median age of 71 years. The overall technical success was 97.9%. Clinical success was 87.6%. Because the median follow-up was only 13.0 months (range, 1-89 months), data on long-term success are almost absent. Four cases (2.1%) of secondary aneurysm rupture after embolization owing to endoleak recurrence were reported. All ruptures occurred in aneurysms exceeding initial treatment diameter of 70 mm.

CONCLUSIONS

Initial technical success after liquid embolization for T1EL is high, although long-term clinical success rates are lacking. Within this review, the risk of secondary rupture is comparable with untreated T1EL at 2% with a median follow-up of 13 months, regardless of the initial success of embolization. In general, no decrease in secondary aneurysm rupture after embolization of T1EL after EVAR is demonstrated, although the results of late embolization are debated.

Novel open technique for repair of endograft migration

Widespread adoption of endovascular aneurysm repair has led to increased incidence of late complications, such as endograft migration. Treatment options have to be tailored to the patient's health, quality of proximal aorta, and extent of migration. Complete or partial endograft removal is associated with significant morbidity and mortality. We describe a case in which open repair with endograft preservation was employed, with the additional benefit of a sutured proximal anastomosis.

ChEVAS: Combining Suprarenal EVAS with Chimney Technique

Endovascular sealing with the Nellix(®) endoprosthesis (EVAS) is a new technique to treat infrarenal abdominal aortic aneurysms. We describe the use of endovascular sealing in conjunction with chimney stents for the renal arteries (chEVAS) in two patients, one with a refractory type Ia endoleak and an expanding aneurysm, and one with a large juxtarenal aneurysm unsuitable for fenestrated endovascular repair (EVAR). Both aneurysms were successfully excluded. Our report confirms the utility of chEVAS in challenging cases, where suprarenal seal is necessary. We suggest that, due to lack of knowledge on its durability, chEVAS should only been considered when more conventional treatment modalities (open repair and fenestrated EVAR) are deemed difficult or unfeasible.