Latest evidence on chimney endovascular repair of abdominal aortic aneurysms and the renal artery angulation pitfall

This article summarizes the key findings in literature up to date on the endovascular treatment of complex abdominal aortic aneurysms (AAAs) employing the chimney technique. Additionally, an unexplored pitfall is described regarding the target vessel angulation. Although balloon-expandable covered stents present more favorable configuration in downward-oriented target vessels, transverse and upward-oriented target vessels may benefit from other endovascular techniques imploring careful case planning and further investigation on the topic.

Comparative outcomes of physician-modified fenestrated/branched endovascular aortic aneurysm repair in the setting of prior failed endovascular aneurysm repair

OBJECTIVE

Endovascular treatment of aortic aneurysms involving renal-mesenteric arteries, especially in the setting of prior failed endovascular aneurysm repair (EVAR) typically requires fenestrated/branched endovascular aneurysm repair (F/BEVAR) with a custom-made device (CMD). CMDs are limited to select centers, and physician-modified endografts are an alternative treatment platform. Currently, there is no data on the outcomes of physician-modified F/BEVAR (PM-F/BEVAR) in the setting of failed prior EVAR. The purpose of this study was to evaluate the use of PM-F/BEVAR in patients with prior failed EVAR.

METHODS

A prospective database of consecutive patients treated at a single center with PM-F/BEVAR between March 2021 and November 2022 was retrospectively reviewed. The cohort was stratified by presence of a failed EVAR (type Ia endoleak or aneurysm development proximal to a prior EVAR) prior to PM-F/BEVAR. Demographics, operative details, and postoperative complications were compared between the groups using univariate analysis. One-year survival and freedom from reintervention were compared using the Kaplan-Meier method.

RESULTS

A total of 103 patients underwent PM-F/BEVAR during the study period; 27 (26%) were in the setting of prior EVAR. Patients with prior failed EVAR had similar age (75.2 ± 7.7 vs 71.5 ± 8.8 years; P = .058), male gender (n = 24 ; 89% vs n = 57 ; 75%; P = .130), and comorbid conditions except higher incidence of moderate-to-severe chronic obstructive pulmonary disease (n = 7 ; 26% vs n = 7 ; 9%; P = .047). Overall, aneurysm diameter was 65.5 ± 13.9 mm with aneurysms categorized as juxta-/pararenal in 43% and thoracoabdominal in 57%, with no differences between the groups. Twelve patients (14%) presented with symptomatic/ruptured aneurysms. The average number of target arteries incorporated per patient was 3.8. Four different aortic devices were modified with a greater proportion of Terumo TREO devices used in the failed EVAR group (P = .03). There was no difference in procedure time, radiation dose, or iodinated contrast use between groups. Overall technical success was 99%. Rates of 30-day mortality (n = 0 ; 0% vs n = 3 ; 4%; P = .565) and major adverse events (n = 6 ; 22% vs n = 16 ; 21%; P = 1.0) were similar between groups. For the overall cohort, rates of type 1 or 3 endoleak, branch vessel stenosis/occlusion, and reintervention were 2%, 1%, and 8%, respectively, with no difference between groups. One-year survival (failed EVAR 94% vs no EVAR 82%; P = .756) was similar between groups.

CONCLUSIONS

PM-F/BEVAR is a safe and effective treatment for patients with aneurysms involving the renal-mesenteric arteries in the setting of prior failed EVAR where additional technical challenges may be present. Additional follow-up is warranted to demonstrate long-term efficacy, but early results are encouraging and similar to those using CMDs.

The Challenge of Endoleaks in Endovascular Aneurysm Repair (EVAR): A Review of Their Types and Management

An abdominal aortic aneurysm (AAA) is a dilatation of the abdominal aorta above 3 cm or 50% greater than the segment above. It is a dangerous condition accounting for a substantial number of deaths per year and increasing at an alarming rate. Various factors come into play in the development of AAAs, which this study has elaborated on, including smoking and old age, demographics, and comorbid conditions. Endovascular aneurysm repair (EVAR) is a newer treatment modality used for AAAs in which an endograft device is placed into the aorta, thereby creating a bypass tract from the aneurysm and generating flow mimicking that of the natural aorta. It is minimally invasive and associated with less postoperative mortality and reduced hospital stay. However, EVAR is also associated with significant postoperative complications, including endoleaks, which were reviewed in depth. Endoleaks are postprocedural leaks into the aneurysm sac that are usually identified immediately after graft placement and indicate treatment failure. They are of five subtypes, categorized according to their mechanism of development. The most common type is type II endoleaks, and the most dangerous is type I endoleaks. Each subtype has multiple management options with varying rates of success. Prompt identification along with appropriate treatment of endoleaks can lead to better postoperative outcomes and improved quality of life for patients.

Use of Chimney Technique Does Not Improve the Outcome of Endovascular Aneurysm Repair in Patients With a Hyperangulated and Short Proximal Aortic Neck

PURPOSE

We hypothesized that extending the proximal landing zone with the chimney technique could be beneficial in patients with a hyperangulated proximal aortic neck, defined as more > 60 degrees.

MATERIAL AND METHODS

We retrospectively analyzed the outcome of prospectively collected data of patients treated by endovascular aneurysm repair (EVAR) for infrarenal aortic aneurysm with a hyperangulated proximal aortic neck. In all, 104 out of 130 patients were treated without (Group A) and 24 with the chimney endovascular aortic repair (ChEVAR, Group B). Primary outcome was technical and clinical success according to the reporting standards of the Society of Vascular Surgery.

RESULTS

The use of the chimney technique was associated with a significantly longer operation duration (167 vs. 93 min, p < .001), longer fluoroscopy time (44 vs.30 min, p = < .001), and larger amount of contrast medium used (149 vs. 127 ml, p = .03) but did not significantly improve technical (79.2% vs. 87.7%) and clinical success (54.2% vs. 68.9%). Aneurysm-related mortality was higher in group B (8.3% vs. = 0%, p < .001). Type IA endoleak was high in both groups at completion angiography (11.3% in Group A vs. 12.5% in Group B) and at follow-up (10.4% in Group A vs. 4.5% in Group B) without significant difference between the groups.

CONCLUSIONS

Our data did not show a benefit of the primary use of the chimney technique in patients with a hyperangulated and short neck, although more studies are required to support this conclusion. Other strategies or new technologies are required for improving EVAR results in aneurysm patients with severe angulated proximal and short neck.

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.

Long-term chimney/snorkel endovascular aortic aneurysm repair experience for complex abdominal aortic pathologies within the PERICLES registry

OBJECTIVE

The early and short-term efficacy of the snorkel/chimney technique for endovascular aortic aneurysm repair (ch-EVAR) have been previously reported. However, long-term ch-EVAR performance, vessel patency, and patient survival remain unknown. Our study evaluated the late outcomes to identify possible predictors of failure within the PERICLES (performance of the chimney technique for the treatment of complex aortic pathologies) registry.

METHODS

Clinical and radiographic data from patients who had undergone ch-EVAR from 2008 to 2014 in the PERICLES registry were updated with an extension of the follow-up. Regression models were used to evaluate the relevant anatomic and operative characteristics as factors influencing the late results. We focused on patients with ≥30 months of follow-up (mean, 46.6 months; range, 30-120 months).

RESULTS

A total of 517 patients from the initial PERICLES registry were included in the present analysis, from which the mean follow-up was updated from 17.1 months to 28.2 months (range, 1-120 months). All-cause mortality at the latest follow-up was 25.5% (n = 132), with an estimated patient survival of 87.6%, 74.4%, and 66.1% at 1, 3, and 5 years, respectively. A subgroup of 244 patients with 387 chimney grafts placed (335 renal arteries, 42 superior mesenteric arteries, 10 celiac arteries) and follow-up for ≥30 months was used to analyze specific anatomic and device predictors of adverse events. In the subgroup, the technical success was 88.9%, and the primary patency was 94%, 92.8%, 92%, and 90.5% at 2.5, 3, 4, and 5 years, respectively. The mean aneurysm sac regression was 7.8 ± 11.4 mm (P < .0001). Chimney graft occlusion had occurred in 24 target vessels (6.2%). Late open conversion was required in 5 patients for endograft infection in 2, persistent type Ia endoleak in 2, and endotension in 1 patient. The absence of an infrarenal neck (odds ratio, 2.86; 95% confidence interval, 1.32-6.19; P = .007) was significantly associated with long-term device-related complications. A sealing zone diameter >30 mm was significantly associated with persistent or late type Ia endoleak (odds ratio, 4.86; 95% confidence interval, 1.42-16.59; P = .012).

CONCLUSIONS

The present analysis of the PERICLES registry has provided the missing long-term experience for the ch-EVAR technique, showing favorable results with more than one half of the patients surviving for >5 years and a chimney graft branch vessel patency of 92%. The absence of an infrarenal neck and treatment with a sealing zone diameter >30 mm were the main anatomic long-term limits of the technique, requiring adequate preoperative planning and determination of the appropriate indication.

Chimney technique with endoanchors in treatment of late type 1a endoleak after endovascular aortic repair

The late type Ia endoleak after endovascular aortic repair could be a challenging issue. Over the last years, in case of short or enlarged neck, fenestrated and branched stent grafts have been increasingly employed with improving results. However, these devices have limited use in urgent/emergent cases as custom graft manufacturing takes long time, and may not be fit in patients with particular anatomic features. In this setting, chimney and relining remain an alternative but sometimes may not be adequate. According to literature, the use of the endoanchors associated to chimney technique can improve the procedure results in primary endovascular aortic repair. We treated two patients with a late type Ia endoleak after endovascular aortic repair with a simultaneous relining, single renal chimney, and endoanchors implant. These patients were valuated unfit for open repair with neck configuration unadapt for a simple relining, ballooning, or stenting. The patient conditions were unfavorable for an endovascular repair with branched endovascular aortic repair–fenestrated endovascular aortic repair. The same procedure was performed in both patients. Postoperative angio-computed tomographic scan demonstrated the resolution of the endoleak with patency of renal graft. Our preliminary experience, in these selected cases, demonstrate the feasibility of the technique in late type Ia endoleak.

Predictors of inadequate EndoAnchors aortic wall penetration for the Endosutured therapy in hostile neck patients

BACKGROUND

The use of EndoAnchors is increasing; however, not much about appropriate use in terms of aortic wall penetration (AWP) is described. We aim to evaluate the procedural and anatomical conditions related with borderline (b) or absence (ab) of AWP when checked on first CT-scan after the Endosutured aortic repair (ESAR) for hostile neck anatomies (HNA).

METHODS

This study with NCT04100499 is a single center prospective evaluation of patients receiving EndoAnchors for prevention or treatment of a proximal EVAR failure. AWP was evaluated on first CT-scan and findings correlated with neck anatomical features and procedural data. The sum of borderline and absence of AWP was considered as Inadequate - In-AWP (failure). Adjunctive procedures, reinterventions, all-cause mortality, absence of type Ia EL and aneurysm related mortality are also described.

RESULTS

Forty-eight patients were treated during the study period and 43 high-surgical risk patients were finally included in the study for analysis with at least one HNA criteria (58%) and associating two in 21% or even three in 21%. A total of 250 EndoAnchors were deployed at a median 6 (range, 4-10) per case. From those, 31 (12.5%) achieved b-AWP and 11 (4.4%) ab-AWP, meaning 42 (16.8%) EndoAnchors with In-AWP. Univariate-analysis showed being an occasional user and a therapeutic case as predictor for at least one and more failures. The only predictor on multivariate analysis for two or more EndoAnchors with In-AWP was being an occasional user. Cumulative-survival and freedom from type-Ia EL at 2-years was 84% and 95%; respectively.

CONCLUSIONS

Outcomes of the ESAR therapy should be validated according to their aortic wall penetration checked on first CT-scan. EndoAnchors use in HNA should not be considered an easy approach for the endovascular technique, especially for therapeutic cases. An individual and specific case analysis counterbalancing inadequate use of the device in unexperienced users should be evaluated against the increased risk of proximal failure as in standard EVAR alone during HNA treatment.

Gutter Characteristics and Stent Compression of Self-Expanding vs Balloon-Expandable Chimney Grafts in Juxtarenal Aneurysm Models

Purpose: To assess in silicone juxtarenal aneurysm models the gutter characteristics and compression of different types of chimney graft (CG) configurations. Materials and Methods: Fifty-seven combinations of Excluder C3 or Conformable Excluder stent-grafts (23, 26, and 28.5 mm) were deployed in 2 silicone juxtarenal aneurysm models with 3 types of CGs: Viabahn self-expanding (VSE; 6 and 13 mm) or Viabahn balloon-expandable (VBX; 6, 10, and 12 mm) stent-grafts and Advanta V12 balloon-expandable stent-grafts (ABX; 6 and 12 mm). Setups were divided into 4 groups on the basis of increasing CG and main graft (MG) diameters. Two independent observers assessed gutter size and type as well as CG compression on computed tomography scans using postprocessing software. Results: In the smaller diameter combinations (6-mm CG and 23-, 26-, and 28.5-mm MGs), both VSE (p=0.006 to 0.050) and ABX (p=0.045 to 0.050) showed lower gutter areas and volumes compared with VBX. In turn, the VBX showed a nonsignificant tendency to decreased compression, especially compared to ABX. Use of the Excluder C3 showed a 6-fold increase in type A1 gutters (related to type Ia endoleak) as compared to the Conformable Excluder (p=0.018). Balloon-expandable stent-grafts (both ABX and VBX) showed a 3-fold increase in type A1 gutters in comparison with self-expanding stent-grafts (p=0.008). Conclusion: The current study suggests that use of the Conformable Excluder in combination with VSE chimney grafts is superior to the other tested CG/MG combinations in terms of gutter size, gutter type, and CG compression.

The role of fEVAR, chEVAR and open repair in treatment of juxtarenal aneurysms: a systematic review

INTRODUCTION

Open repair (OR), fenestrated endovascular aneurysm repair (fEVAR) and endovascular exclusion using parallel graft (chEVAR) are complementary procedures used for treatment of juxtarenal abdominal aortic aneurysm (jrAAA). The aim of our study was to assess available literature and analyze dispersion of OR, fEVAR and chEVAR procedures among reported papers related to treatment of jrAAA.

EVIDENCE ACQUISITION

The PubMed database was systematically searched using predefined strategy and key words related to treatment of jrAAA on September 28th, 2019. Studies were assessed for eligibility using the inclusion and exclusion criteria with at least five patients treated with at least one of the procedures while systematic reviews, meta-analysis, reviews, comments, editorials and letters were excluded as well as studies without clear classification of the location of the aneurysm, studies not specifying the number of patients treated with each of the techniques or not discriminated between aortic pathologies (juxtarenal, paravisceral and thoracoabdominal), hybrid procedures, endoanchors or with branched stent-graft.

EVIDENCE SYNTHESIS

Overall, 1533 papers were identified while papers that met inclusion criteria were either representing experience of single institution (87 papers) or from multicenter studies (6 papers), national or international registries (18 papers). In the period between January 1977 and December 2017, treatment of 5664 patients with jrAAA was reported in 87 papers as a single institution report. Out of them 2531 (45%) were treated with OR, 2592 (46%) with fEVAR and 541 (9%) with chEVAR. Out of 29 institutions reporting OR, there were 11 (37.9%) with more than 100 treated patients while 21 (41.1%) out of 51 institutions that reported more than 50 jrAAA treated with fEVAR. Only four institutions reported results of all three treatment modalities.

CONCLUSIONS

Based on the results reported in the literature, regardless of its complexity and costs, fEVAR for jrAAA has been accepted in substantial number of hospitals worldwide, while number of reported procedures is reaching OR.

FEVAR/BEVAR have limitations and do not always represent the preferred option for juxtarenal reconstruction

Following the definition given by the recent ESVS guidelines, juxtarenal abdominal aortic aneurysm (JAAA) is defined as an aneurysm extending up to but not involving the renal arteries, necessitating suprarenal aortic clamping for open surgery, i.e. a short neck (<10 mm). JAAA repair always represents a challenge intervention, either by open or endovascular means, mostly related to the renal arteries involvement. Concerning endovascular repair, different options can be considered. Among them, fenestrated endografts (FEVAR) should be considered as a first option1, due to their reported safety and efficacy. However, when the anatomy is not favorable or when FEVAR devices are not available in an emergency setting for instance, other alternatives can be considered like parallel graft or chimney technique (ChEVAR). Do nothing is the last alternative when medical and anatomical circumstances are absolutely poor. In the following pages, we will review the limitations of FEVAR and branched endografts, the better indications and anatomical conditions for a successful repair with ChEVAR technique and its current clinical results reported in the literature.

Outcomes of endovascular treatment of endoleak type Ia after EVAR: a systematic review of the literature

INTRODUCTION

Endovascular repair of infra-renal aortic aneurysm (EVAR) has become treatment of choice. However, individuals undergoing EVAR have a high re-intervention rate. The aim of this study is to evaluate the current endovascular treatment modalities of endoleak type Ia (ET Ia) treatment after EVAR and their outcome.

EVIDENCE ACQUISITION

A systematic review and meta-analysis was performed. MEDLINE, EMBASE and Cochrane databases were searched with PRISMA methodology for studies reporting on endovascular treatment of ET Ia after EVAR. Studies presenting treatment of intra-operative ET Ia were excluded.

EVIDENCE SYNTHESIS

Two international registries, fourteen non-randomized retrospective and twelve case-report studies were included reporting on 356 patients. Reported endovascular techniques included fenestrated-, branched-, chimney EVAR, endovascular sealing (EVAS), endoanchors, embolization techniques, cuff and/or "giant" Palmaz stents. Technical success rate ranged from 90% to 100%, with intra-operative mortality rate of 0%. During early period, persistence of ET Ia was 3.4% (9/262) and the re-intervention rate was 3.5% (8/227). The 30-day mortality rate was 2% (7/356). Mean follow-up was 22.4 months±18. Presence of ET Ia was 5.9% (21/356), and the reintervention rate was 5.1% (18/349). The mortality rate was 13% (26/203), while the primary patency rate of TVs ranged from 94.3% to 100%.

CONCLUSIONS

A multitude of techniques for endovascular repair for ET Ia exists. No strong evidence supports one specific technique. The early and mid-term outcomes are encouraging in terms of ET Ia resolution, mortality and morbidity rates.