Chimney Endovascular Aneurysm Repair Research Articles

Initial experience of endovascular aneurysm repair at the Dr. Eduardo Liceaga General Hospital of Mexico

Background: Abdominal aortic aneurysm (AAA) is the permanent and irreversible dilation of the lower part of the aorta where the vessel expands, making it susceptible to rupture, which represents a high mortality incident. Methods: A review of clinical records was carried out from September 2021 to March 2023, patients who were diagnosed with aortic aneurysm were included in whom endovascular exclusion of abdominal and thoracic aortic aneurysm was performed at the General Hospital of Mexico by the angiology vascular and endovascular surgery department. Results: 18 endovascular repairs of aortic aneurysms were performed, of which 15.4% were female (n=6) and 84.6% male (n=12). The average proximal neck diameter in the thoracic aorta was 31 mm, average proximal neck diameter in infrarenal AAA 22.2 mm, average aneurysmal diameter in infrarenal segment 63.8 mm, thoracic 31 mm. Regarding the type of endovascular procedure, 11.1% were repaired with the fenestrated endovascular aneurysm repair (FEVAR) technique, and the same proportion with chimney endovascular aneurysm repair (ChEVAR), for a resolution with conventional EVAR of 77.7%. Complications occurred in 3 patients, 2 of which resulted in type 1a and 1b endoleaks that were reoperated and repaired with a proximal cuff, balloon angioplasty, and embolization of the aneurysmal sac with coils. Conclusions: Aortic aneurysm remains a major cause of death in adults because of aortic rupture despite advances over the past two decades that have been made in the endovascular management of large, symptomatic, and ruptured. Timely treatment is essential to prevent rupture and poor patient outcomes.

Long-term outcomes of chimney endovascular aneurysm repair procedure for complex abdominal aortic pathologies

ObjectiveThe aim of this study was to update our earlier experience and to evaluate long-term outcomes of chimney endovascular aortic repair performed for selected cases with complex abdominal aortic aneurysm. MethodsA single-center retrospective cohort study was conducted on 51 consecutive patients who underwent chimney endovascular aortic repair procedure, deemed unfit for open surgical repair and fenestrated endovascular aneurysm repair, from October 2009 to November 2019. Kaplan-Meier analyses were used to assess the estimated overall survival, freedom from aneurysm related mortality, freedom from reintervention, freedom from target vessel instability, and freedom from type Ia endoleaks. ResultsFifty-one patients (mean age, 77.1 ± 7.5 years) with a mean preoperative maximum aneurysm diameter of 74.2 ± 20.1 mm were included. Mean follow-up duration was 48.6 months (range, 0-136 months). Estimated overall survival at 5 and 7 years was 36.3% ± 7.1% and 18.3% ± 6.0%, respectively. Freedom from aneurysm-related mortality was 88.6% ± 4.9% at 7 years. Estimated freedom from type Ia endoleaks at 7 years was 91.8% ± 3.9%. A total of 21 late reinterventions were performed in 17 patients (33%). Most of them were performed to treat type II endoleaks with sac growth (47.6%; n = 10) and type Ib endoleak (23.8%; n = 5). Estimated freedom from reintervention at 7 years was 56.3% ± 7.9%. Estimated freedom from target vessel instability at 7 years was 91.5% ± 4.1%. ConclusionsThe 7-year results of chimney endovascular aortic repair procedures performed in our center confirm the long-term safety and effectiveness of this technique in a series of high-risk patients with large aneurysms. The present study has, to the best of our knowledge, the longest follow-up for patients treated with chimney endovascular aortic repair, and it provides data to the scarce literature on the long-term outcomes of this procedure, showing acceptable to good long-term results.

A Comparison Between Chimney EVAR and Branched or Fenestrated EVAR for the Treatment of Juxtarenal Aneurysms: A Single-center Experience

A Comparison Between Chimney EVAR and Branched or Fenestrated EVAR for the Treatment of Juxtarenal Aneurysms: A Single-center Experience

In Vitro Radiological Evaluation of Different Types of Chimney Stents Using a Silicon Flow Model with Adjustable Physiological Simulating Conditions

To evaluate invitro the performance of invivo published covered or bare metal chimney stents (ChSs) in combination with the Endurant II abdominal endograft (Medtronic) as the only CE approved main graft (MG) in the treatment of juxtarenal abdominal aortic aneurysms with the chimney endovascular aneurysm repair (chEVAR) technique. Bench top experimental study. A silicon flow model with adjustable physiological simulating conditions and patient based anatomy was used to test nine different MG-ChS combinations: Advanta V12 (Getinge); BeGraft+ (Bentley); VBX (Gore & Associates Inc.); LifeStream (Bard Medical); Dynamic (Biotronik); Absolute Pro (Abbott); double Absolute Pro; Viabahn (Gore) lined with Dynamic; and Viabahn lined with EverFlex (Medtronic). Angiotomography was performed after each implantation. DICOM data were analysed blindly twice per observer by three independent experienced observers. Each blinded evaluation was performed at one month intervals. The main analysed parameters were the area of gutters, MG and ChS maximum compression, and the presence of infolding. Bland-Altman analysis confirmed adequate results correlation (p < .05). Each employed ChS showed significantly different performance favouring the balloon expandable covered stent (BECS). The smallest gutter area was seen in the combination with Advanta V12 (0.26 cm2). MG infolding was observed in all tests. The lowest ChS compression was observed in the combination with BeGraft+ (compression 4.91%, D ratio 0.95). In our model, BECSs showed higher angulations than bare metal stents (BMSs) (p < .001). This invitro study shows the variability of performance with each theoretically possible ChS and explains the divergent ChS outcomes in the published literature. BECS in combination with the Endurant abdominal device confirms their superiority vs. BMS. The presence of MG infolding in each test underlines the need for prolonged kissing ballooning. Angulation evaluation and comparison with other invitro and invivo publications demands the need for further investigation in transversely or upwardly oriented target vessels.

Transrenal Endovascular Aneurysm Repair–A Novel Approach for Abdominal Aortic Aneurysms with Difficult Neck Anatomy

The endovascular approach to treating ruptured or symptomatic abdominal aortic aneurysms (AAA) with difficult neck anatomy still poses a major challenge. This study proposes and evaluates the outcomes of a novel technique, Transrenal Endovascular Aneurysm Repair (Tr-EVAR) which utilizes the top ring 'valley' and 'peak' configuration of the Anaconda stent graft to achieve proximal seal in AAAs with an unfavourable neck. All patients treated with Tr-EVAR over a period of 10 years were identified retrospectively. Demographic, clinical and outcome data were collected, and survival analysis was performed. The time-to-event was analysed using Kaplan-Meier curves for complication-free survival, reintervention-free survival, and overall survival. During the study period, 36 patients ruptured, symptomatic or large AAAs having unfavourable necks and not fit for open repair underwent Tr-EVAR. Two patients died in the first 30 days post-procedure (5.6%). The overall survival at 1 year, 3 years and 5 years were 86%, 72% and 54% respectively with a mean overall survival of 74.0 months (SE 7.8, 95% CI 58.7 - 89.3) which was comparable to chimney EVAR. The complication-free survival and reintervention-free survival at 1 year, 3 years,5 years were 75%, 61%, 42% and 78%, 64%, 45% respectively. Tr-EVAR can be considered as an off-the-shelf solution for urgent cases not fit for open repair with unfavourable neck features for standard EVAR. Careful patient selection and planning have generated acceptable immediate, mid-and long-term results comparable to those presented by chimney EVAR in the literature.

Comparative clinical study of short-term outcomes between table fenestrated and chimney endovascular aneurysm repair for hostile neck aneurysms.

Hostile neck abdominal aortic aneurysm (AAA) is challenging for standard endovascular aneurysm repair (EVAR). We sought to compare fenestrated endovascular aneurysm repair (fEVAR) and chimney endovascular aneurysm repair (chEVAR) for hostile neck AAA. Patients were identified retrospectively. Hostile neck anatomy was defined as a proximal neck length of <15mm or angulation >60°. The choice of fEVAR or chEVAR was based on neck anatomy and physician preference. Type I endoleak (T1EL) was the primary outcome. Other outcomes included type III endoleak (T3EL), visceral stent occlusion, renal insufficiency, reintervention, and mortality. A total of 84 patients were included from April 2012 to December 2021. fEVAR and chEVAR patients were 48 and 36 cases, respectively. Both groups showed similar rate of T1EL, T3EL, visceral stent occlusion, renal insufficiency, reintervention, and mortality. However, chEVAR patients had a more tortuous neck (61.1% vs. 16.7%, p < 0.001), while fEVAR patients had a greater neck size (29.5 ± 6.3mm vs. 24.5 ± 4.8mm, p < 0.001) and more reconstructing target arteries (2.2 ± 1.1 vs 1.3 ± 0.6, p < 0.001). fEVAR and chEVAR show similar safe and effective outcomes in well-selected hostile neck. fEVAR might be able to reconstruct multiple visceral arteries, and chEVAR seems justified in patients with poor anatomical suitability for fEVAR.

Cause-specific Long-Term Mortality After Physician-Modified Branched/Fenestrated Endovascular Aortic Repair

Physician-modified endografts (PMEG) are being increasingly used for treatment of complex aortic diseases. Several series describe short and mid-term outcomes, but limited long-term data is available. Here we sought to evaluate the long-term causes of death after PMEG, and the association with type and complexity of repair. A single, high-volume, academic aortic referral center retrospectively reviewed all consecutive branched/fenestrated PMEG procedures from 2010 to 2016, which allowed all subjects the opportunity for 5 or more years of survival time. All subjects were deemed either high anatomic and/or physiologic risk for open repair. Commercial custom and chimney EVAR procedures were excluded. Death certificates, obituary websites, and electronic medical records were reviewed to assign cause-specific mortality. The primary end point was all-cause mortality. Secondary end points included cause-specific-death categorized as: major adverse cardiovascular event (myocardial infarction, malignant arrythmia, congestive heart failure, sudden death), malignancy, pulmonary (chronic obstructive pulmonary disease/respiratory failure), infection, aorta-related, and other (including metabolic, stroke, and trauma). Kaplan-Meier methodology was used to estimate survival. A total of 232 consecutive PMEG procedures were analyzed (male, 72%; mean age, 73 ± 8 years). Indications included thoracoabdominal aneurysm (extent I-V; 58%), pararenal AAA (33%), postsurgical pseudoaneurysm or failed EVAR (6%), chronic dissection (2%), and penetrating paravisceral ulceration (1%). A majority were performed electively (75%, n = 174) while the remaining were completed for symptomatic or intact (20%, n = 47) and emergent or ruptured (5%, n = 11) presentations. We included 762 target vessels (celiac, n = 179; superior mesenteric artery, n = 204; renal, n = 379) and most procedures had four-vessel revascularization (61%, n = 142). The 30-day mortality rates were: elective, 3% (n = 5/174) and nonelective, 14% (n = 8/58). Secondary interventions occurred in 18% (n = 42). The mean survival was 4.9 ± 3.2 years (median, 5.4; interquartile range, 1.9-7.5; 95% confidence interval [CI], 4.9-6.1) and 57% (n = 132/232) died during follow-up. Among 132 documented deaths, 10% (n = 13/132) occurred before hospital discharge and/or at 30 days or less, whereas 90% (n = 119/132) occurred after 30 days and/or after hospital discharge. Cause-specific mortality was attributed to major adverse cardiovascular events (21%), other causes (18%), aorta related (13%), unknown (13%), pulmonary (12.5%), infection (12.5%), and malignancy (10%). Causes of late aorta-related death (n = 16/232, 6.9% overall; 12.1% of all deaths recorded) were rupture (n = 5) and mesenteric ischemia (n = 2), respectively. Freedom from long-term all-cause and aorta-related mortality was: 5-years, 56 ± 3% and 90 ± 2%; 8-years, 43 ± 4% and 87 ± 3%, respectively (Fig 1). Nonelective presentation had higher long-term risk of all-cause and aorta-related mortality (all-cause: hazard ratio [HR], 1.6; 95% confidence interval, 1.1-2.4; aorta-related: HR; 3.2; 95% confidence interval, 1.2-8.5) (Fig 2). Four-vessel repairs were associated with improved survival (vs fewer than 4 vessels: HR, 0.6; 95% confidence interval, 0.4-0.9). PMEG in high-risk patients was durable and provided excellent long-term outcomes in patients deemed high risk for open repair. Cardiovascular morbidity is the most significant factor leading to late mortality after PMEG. Aorta-related mortality is low; however, elective repairs with more proximal coverage appear to be protective from poor long-term outcomes.Fig 2Freedom from aorta-related death after physician-modified endograft (PMEG) by presentation (includes perioperative deaths).View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Chimney endovascular aneurysm repair (ChEVAR) for hostile neck complex aneurysm.

Recent guidelines recognize the role of chimney endovascular aneurysm repair (ChEVAR) in the treatment of complex aortic disorders. The optimal configuration and number of visceral vessels that can be incorporated is still controversial. We aim to review outcomes from a multi-institutional decade-long experience with ChEVAR. Patients undergoing ChEVAR with multiple (≥2) chimney branches were selected from a prospectively maintained database at the two academic university hospitals. All patients were poorly suited for fenestrated or branched endograft repair (F/BEVAR) and deemed poor-risk for open surgery. Forty-nine multiple ChEVAR were performed in 44 men and 5 women, with complete outcome data at a mean follow-up of 18months. Overall, 2 patients died during follow-up (4%) with no aneurysm-related mortality and two ruptures after ChEVAR (4.1%) due to a type Ib endoleak from iliac limb pullout and persistent gutter-flow, both repaired with endovascular means. No stroke or spinal cord ischemia was noted during the follow-up period. Reintervention was undertaken in eight patients (16.3%) with five reinterventions for persistent gutter-flow and four chimney graft-associated. Three-vessel ChEVAR was performed in 16 patients, with two-vessel ChEVAR in 33 patients for a total of 114 chimney branches (mean 2.3 chimneys per patient). There were 21 superior mesenteric artery (SMA), 45 right renal, 46 left renal artery (LRA), and two accessory LRA chimneys placed. Antegrade configuration of chimney branches was chosen in 43 patients (88%). There were no significant differences between three-vessel and two-vessel ChEVAR upon univariate analysis in aneurysm size (65.6 vs 60.5mm; p = 0.059), iliac diameter (7.3 vs 7.1mm; p = 0.85), or endograft oversizing (30 vs 32.5%; p = 0.43). Three-vessel ChEVAR was associated with a larger aneurysm neck diameter (28.4 vs 25.0mm; p = 0.021), shorter native infrarenal neck (0.5 vs 3.37mm; p = 0.002) as well as longer seal zone (36.33 vs 22.67mm; p = 0.005) compared with two-vessel ChEVAR. At follow-up, there were no significant differences in gutter area between three-vessel and two-vessel ChEVAR (18.9 vs 15.7mm3; p = 0.73) nor the rate of persistent gutter-flow (12.5 vs 9.1%; p = 0.71). Reintervention to multiple chimney grafts and for persistent gutter-flow is higher compared to single chimneys and demands close surveillance. However, based upon this combined transantlantic experience, we believe multiple ChEVAR provides a reasonable and safe option for complex aortic aneurysm repair when open or custom endografts are not available or indicated based on their Instructions For use, even when triple chimney grafts are required. The optimal configuration for multiple ChEVAR still warrants further study, although theoretical preliminary advantages may exist for a combination of antegrade and retrograde chimneys.

Incidence of Contrast-Induced Nephropathy and Post-Operative Outcomes in Patients Undergoing Chimney Endovascular Aortic Aneurysm Repair.

Chimney endovascular aortic aneurysm repair (ch-EVAR) has become a valid alternative to treat complex aneurysms but the occurrence of contrast-induced kidney injury (CI-AKI) is poorly known. This study investigated the incidence and the impact of CI-AKI on post-operative outcomes after ch-EVAR. Consecutive patients who underwent ch-EVAR between July 2010 and 2021 were retrospectively included. CI-AKI was defined based on plasma creatinine levels within 7days after the intervention according to the "Kidney Disease Improving Global Outcomes" (KDIGO) classification. Among 102 patients included, CI-AKI occurred in 14 cases (13.7%). The 30-day post-operative mortality and complications were significantly higher in patients who developed CI-AKI compared with those who did not (50 vs 9.1%, P = .001 and 57.1 vs 20.5%, P = .007). Over a median follow-up of 24months (3-39), overall mortality was also significantly higher (78.6 vs 33.0%, P = .002). The pre-operative platelet-to-lymphocyte ratio (PLR) was significantly higher in patients who developed CI-AKI (224.5 vs 147.6, P = .008). CI-AKI is frequent after ch-EVAR and is associated with worse post-operative outcomes. This should increase awareness of clinicians to optimize preventive and therapeutic strategies.

Results from a nationwide prospective registry on open surgical or endovascular repair of juxtarenal abdominal aortic aneurysms.

Juxtarenal abdominal aortic aneurysms (JRAAAs) can be treated either with open surgical repair (OSR) including suprarenal clamping or by complex endovascular aneurysm repair (cEVAR). In this study, we present the comparison between the short-term mortality and complications of the elective JRAAA treatment modalities from a national database reflecting daily practice in The Netherlands. All patients undergoing elective JRAAA open repair or cEVAR (fenestrated EVAR or chimney EVAR) between January 2016 and December 2018 registered in the Dutch Surgical Aneurysm Audit (DSAA) were eligible for inclusion. Descriptive perioperative variables and outcomes were compared between patients treated with open surgery or endovascularly. Adjusted odds ratios for short-term outcomes were calculated by logistic regression analysis. In all, 455 primary treated patients with JRAAAs could be included (258 OSR, 197 cEVAR). Younger patients and female patients were treated more often with OSR vs cEVAR (72± 6.1 vs 76± 6.0; P< .001 and 22% vs 15%; P= .047, respectively). Patients treated with OSR had significantly more major and minor complications as well as a higher chance of early mortality (OSR vs cEVAR, 45% vs 21%; P< .001; 34% vs 23%; P= .011; and 6.6% vs 2.5%; P= .046, respectively). After logistic regression with adjustment for confounders, patients who were treated with OSR showed an odds ratio of 3.64 (95% confidence interval [CI], 2.25-5.89; P< .001) for major complications compared with patients treated with cEVAR, and for minor complications, the odds ratios were 2.17 (95% CI, 1.34-3.53; P= .002) higher. For early mortality, the odds ratios were 3.79 (95% CI, 1.26-11.34; P= .017) higher after OSR compared with cEVAR. In this study, after primary elective OSR for JRAAA, the odds for major complications, minor complications, and short-term mortality were significantly higher compared with cEVAR.

Impact of renal chimney intra-aortic stent length on branch and end-stent angle in chimney endovascular aneurysm repair and endovascular aneurysm sealing configurations.

Practice patterns and durability of parallel stent graft techniques in complex endovascular aneurysm repair (EVAR) remain poorly defined. We aimed to quantify and compare the impact of renal chimney intra-aortic stent length (IASL) on geometric deformations of renal arteries in complex EVAR. Thirty-eight nonconsecutive patients underwent EVAR utilizing parallel stent graft techniques (chimney EVAR [chEVAR], n = 28; chimney endovascular aneurysm sealing [chEVAS], n = 10) between 2010 and 2016. A total of 59 renal chimney stent grafts were used. Geometric quantification was derived from three-dimensional model-based centerline extraction. Renal chimney intra-aortic stent length (IASL) was defined as the length of chimney stent that extended from the proximal edge of the chimney stent to the ostium of the corresponding renal artery. Mean IASL for both left and right renal arteries in the cohort was 35.7mm. Renal arteries containing chimney IASL <30mm trended toward a greater branch angle (135.4 vs. 127.8°, p = .06). Left renal arteries showed significantly greater branch angle among those with IASL <40mm (135.5 vs. 121.7°, p = .045). Mean IASL for renal arteries in chEVAR was significantly longer compared to chEVAS (39.2 vs. 26.3mm, p = .003). No difference was noted in overall branch angle or end-stent angle based on procedure type. ChEVAR with IASL <30mm had significantly greater end-stent angle (48.2 vs. 33.5°, p = .03). In contrast, chEVAS patients showed no difference in end-stent angle based on IASL thresholds, but did have significantly greater branch angle among those with IASL <30mm when grouped by both all renal arteries (133.5 vs. 113.5°, p = .004) and right renal arteries (134.3 vs. 111.6°, p = .02). Renal chimney stents with longer IASL appear to exhibit less renal artery deformation, suggesting a more gradual and perpendicular transition of the chimney stent across the renal ostium.

Multicenter Mid-Term Outcomes of the Chimney Technique in the Elective Treatment of Degenerative Pararenal Aortic Aneurysms

Purpose Chimney endovascular abdominal aortic aneurysm repair (CHEVAR) has predominantly been described as an alternative technique for the management of urgent presentations of degenerative pararenal aortic aneurysms (dPAAs). However, the role of CHEVAR in the treatment of asymptomatic patients remains unknown. The aim of current multinational study was to evaluate the outcomes of elective CHEVAR of dPAAs. Material and Methods Retrospective analysis of 267 consecutive dPAA patients treated with elective CHEVAR at 13 European and US centers from 2008 to 2014. Primary endpoints were 30 days and out of hospital CHEVAR-related mortality. Secondary endpoints included persistent type Ia endoleak or endotension, angiographically confirmed occlusion and/or high-grade chimney graft (CG) or involved splanchnic vessel stenosis identified at index procedure and/or during follow-up, as well as CHEVAR-related re-intervention. Results Mean follow-up time was 25.5±13.3 months. The 442 visceral vessels were involved and mean number of CGs per patient was 1.63±0.7. 436 targeted vessels were successfully cannulated. The aortic graft intentionally covered 6 renal arteries and immediate technical success was 98.6%. The 30 days mortality was 1.9% (n=5), while the in-hospital complication rate was 10.1% (n=27) including 3 strokes, 1 permanent dialysis, and 1 intestinal ischemia. No 30 day type Ia endoleaks were detected and 3.2% of CGs (n=14, including the intentionally covered) had evidence of occlusion and/or stenosis. The overall CHEVAR-related mortality was 2.2% (n=6). Freedom from primary and secondary type Ia endoleak/endotension rates at 3 years was 93.0% and 98.0%, respectively. Primary and secondary CG patency was 87.0% and 89.0%. Primary and secondary endovascular freedom from any endpoint at 3 years was 81.0% and 94.0% respectively. Conclusion Elective use of CHEVAR in the management of dPAAs seems to be durable. These results are comparable to published outcomes with other total endovascular strategies, which justifies an expanded role for CHEVAR in the treatment of asymptomatic patients presenting with dPAAs.

A Case of Abdominal Aortic Rupture Treated by Chimney EVAR

腹部大動脈修復部位の感染破綻により大動脈破裂を発症した症例に対して，Chimney techniqueを用いて止血術を行い救命した症例を経験したので報告する．症例は62歳，女性．下行結腸癌術後リンパ節転移に対して4回の手術歴があり，4回目の術中に腹部大動脈を損傷し血管修復術と左腎臓摘出術を行った．術後，直腸吻合部の縫合不全による腹膜炎を発症し，大動脈修復部位の感染にひき続いて大動脈破裂を発症した．破裂部位は左腎動脈レベルの近傍であった．大動脈破裂症例であること，腹腔内や後腹膜に高度の癒着が予想され開腹による直接止血は困難であることを考慮し，ステントグラフト留置にはややネック長は短かったが，Chimney techniqueを用いて止血術を行った．術後，endoleakや腎機能悪化を認めず，救命することができた．大動脈破裂症例に対するChimney techniqueは緊急時の治療選択の1つとして有用と考えられた．

How to Deal with the Achilles Heel of the Chimney Endovascular Technique for Complex Aortic Pathologies

In the last decade, the chimney EVAR (CHEVAR) has rapidly evolved. It started as a bailout option to save aortic branches in case of inadvertent coverage during EVAR and developed within 10 years of published evidence to a valid endovascular treatment option of complex abdominal aortic pathologies. Recently, the technique was included in the ESVS 2019 guidelines for treatment of abdominal aortic aneurysms (AAA).4 Despite this tremendous evolution from a bailout approach to a therapeutic modality a gutter-related endoleaks remain the Achilles heel of the technique.

Chimney Endovascular Aneurysm Repair from Below

Chimney endovascular aneurysm repair (ChEVAR) is able to repair a juxtarenal abdominal aortic aneurysm (JRAAA) when open or fenestrated/branched repair are not possible. For placement of the chimney graft(s) upper extremity access is necessary, however, not all patients have a suitable aortic arch anatomy for this. A successful ChEVAR is described with a single chimney graft placed from femoral access using steerable sheath technology.

Use of Stainless-Steel, Balloon-Expandable Chimney Grafts Is Durable Though Caution Is Required When Lining Angulated Renal Arteries

Purpose: To analyze the overall performance of flexible nitinol stents used to line chimney grafts (CGs) during chimney endovascular aneurysm repair (chEVAR) of pararenal pathologies. Materials and Methods: A retrospective review was conducted of all 116 elective patients (mean age 74.3±7.2 years; 103 men) who underwent chEVAR with balloon-expandable Advanta V12/iCAST CGs in combination with the Endurant stent-graft between January 2009 and December 2017 at a single center. CG lining with a nitinol stent was electively performed in 43 target vessels of 32 patients. The Kaplan-Meier method was used to estimate the primary outcomes of CG patency and freedom from reintervention (FFR) at the patient level and according to the use of a stent to line the CG. Estimates are reported with the 95% confidence interval (CI). Adjusted odds ratios (ORs) were calculated to identify any confounding effect between the presence/absence of a stent lining or according to the number of CGs. Results: The mean radiological follow-up was 27.3 months (range 22.1–32.6). During this time, 8 CGs (4.7%) became occluded, 6 of them were lined with stents. Restoration of patency was possible in 3 of the 4 occluded stents that were associated with symptoms. First-year primary patency estimates were 96.9% (95% CI 92.5% to 100%) for the unlined group vs 77.1% (95% CI 58% to 95.3%; p=0.001) for the lined group, while FFR was 87.6% (95% CI 79.9% to 95.2%) vs 83.4% (95% CI 68.1% to 98.6%; p=0.82), respectively. Lining represented an independent risk factor for CG occlusion (OR 9.9, p=0.006). Conclusion: CG lining performed mainly in angulated renal arteries during chEVAR was significantly associated with CG occlusion. These findings highlight the importance of not having the distal part of the CG impinge on the angulated segment of the target vessel.

Current assessment and management of endoleaks after advanced EVAR: new devices, new endoleaks?

ABSTRACT Introduction In recent years there has been an increasing application of advanced EVAR techniques to tackle complex clinical and anatomical scenarios. In a bid to overcome the limitations of the traditional stent-grafts, newer EVAR endografts and techniques have been developed and introduced into clinical practice, permitting endovascular management of difficult infrarenal, juxta-renal and thoracoabdominal aneurysms for which previously there was no endovascular solution. As a consequence, we are now confronted with unique patterns of endoleak requiring customized clinical-radiological assessment and treatment. Despite the increasing body of evidence regarding new EVAR techniques and related endoleaks, current guidelines do not specifically address these issues. Objectives Our review aims to assess risk factors, development, and management strategies of these endoleaks, in the most recent infrarenal EVAR devices and in more complex fenestrated EVAR (FEVAR) and Chimney EVAR (Ch-EVAR). Expert opinion Most new devices have demonstrated types of endoleaks that need specific imaging and treatment, as in EVAS, FEVAR, and ChEVAR. Knowledge of specific stent-graft characteristics and the nature of endoleaks associated with the various procedures facilitates the application of relevant useful imaging. In addition, it should aid development of a customized and practically relevant approach to patient management during intervention and follow-up.

Outcomes of elective use of the chimney endovascular technique in pararenal aortic pathologic processes

ObjectiveIn the treatment of pararenal abdominal aortic aneurysms and aortic pathologic processes, chimney endovascular aneurysm repair (CHEVAR) represents an alternative technique for urgent cases. The aim of the study was to evaluate the outcomes of CHEVAR in the elective setting. MethodsWe performed a retrospective analysis of prospectively collected records of 165 consecutive asymptomatic CHEVAR patients who were treated between March 2009 and January 2018 with the Endurant stent graft (Medtronic, Santa Rosa, Calif). A total of 244 chimney grafts (CGs) were implanted. The primary end point was clinical success, defined as freedom from procedure-related mortality, persistent type IA endoleak, occlusion or high-grade stenosis (>70%) of CGs, and any chimney technique-related secondary procedure for the entire follow-up period. Secondary clinical success included patients with successful treatment of a primary end point with a secondary endovascular procedure. ResultsAll 244 targeted chimney vessels were successfully cannulated. Total perioperative morbidity was 7.8% (n = 13), including 3 (1.8%) cases of bowel ischemia, 1 (0.6%) patient with renal ischemia, and 1 patient (0.6%) with stroke. Median follow-up was 25.5 ± 2.2 months. Both 30-day and follow-up procedure-related mortality rates were 1.8% (n = 3). Primary and secondary freedom from persistent type IA endoleak rates were 96.4% (n = 159) and 99.4% (n = 164), respectively. Primary and secondary CG patency rates were 92.2% (n = 225) and 95.9% (n = 234), respectively. The rate of reinterventions related to the chimney technique was 10.9% (n = 18), and 83.3% of them were performed by endovascular means. The estimated cumulative primary patency and freedom from persistent type IA endoleak were 87.5% and 95.3%, respectively, and the primary and secondary clinical successes rates at midterm were 80.3% and 87.5%, respectively. ConclusionsThe elective use of CHEVAR with the Endurant stent graft in our series showed favorable midterm clinical results, which are similar to the published results of other total endovascular modalities. A prospective randomized trial of elective treatment of pararenal abdominal aortic aneurysms and aortic pathologic processes with current endovascular options is needed to assess the value of CHEVAR in the elective setting.

Stroke rate after endovascular aortic interventions in the Society for Vascular Surgery Vascular Quality Initiative

ObjectiveThe stroke rate after endovascular aneurysm repair (EVAR), particularly complex EVAR such as fenestrated EVAR (FEVAR) and chimney EVAR (chEVAR), is not well defined. Whereas stroke is a well-established risk of thoracic endovascular aortic repair (TEVAR), the impact of procedural characteristics on stroke remains unclear. Therefore, we characterized the risk of stroke after endovascular aortic interventions in the Vascular Quality Initiative database and identified procedural characteristics associated with stroke. MethodsWe performed a retrospective cohort study of patients undergoing infrarenal EVAR, complex EVAR, and TEVAR within the Vascular Quality Initiative between 2011 and 2019. Complex EVAR included FEVAR (with either a Food and Drug Administration-approved custom-manufactured device or physician-modified endovascular graft) and chEVAR. We excluded emergent procedures. The primary outcome was in-hospital stroke. We used multivariable logistic regression to identify procedural characteristics associated with stroke. ResultsWe identified 41,540 EVARs, 1371 complex EVARs, and 4600 TEVARs. The in-hospital stroke rate was 0.1% after EVAR, 0.9% after complex EVAR, and 2.9% after TEVAR. In patients undergoing EVAR, aneurysm diameter >6.5 mm (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.1-2.7; P = .03) and use of a proximal extension cuff (OR, 3.3; 95% CI, 1.4-7.9; P < .01) were independently associated with stroke. Among complex EVARs, stroke rate was 0.7% after FEVAR with a custom-manufactured device, 0.4% after FEVAR with a physician-modified endovascular graft, and 2.1% after chEVAR (P = .08). In multivariable analysis, arm access was associated with 8.4-fold higher odds of stroke (95% CI, 1.7-41; P < .01). Whereas chEVAR was associated with higher odds of stroke in crude analysis, this association did not persist after adjustment for arm access (OR, 1.0; 95% CI, 0.2-4.4; P = .99). In patients undergoing TEVAR, more proximal landing zones were associated with higher risk of stroke compared with zone 4/5 (zone 3: OR, 2.0 [95% CI, 0.9-4.2]; zone 2: OR, 3.8 [95% CI, 1.8-8.2]; zone 0/1: OR, 6.3 [95% CI, 2.8-14]). In terms of procedural characteristics, any involvement of the left subclavian artery was associated with stroke (bypass: OR, 2.5 [95% CI, 1.5-4.0]; stent: OR, 2.7 [95% CI, 0.9-8.5]; covered or occluded: OR, 2.5 [95% CI, 1.5-4.1]). ConclusionsStroke, although rare after elective EVAR, is substantially more common after complex EVAR and TEVAR. Increasing procedural complexity in complex EVAR and TEVAR is associated with a higher stroke rate, a risk that should be factored into clinical decision-making. The strong association between stroke and upper extremity access during complex EVAR is alarming and warrants further study.

Chimney Endovascular Repair of Primary Mycotic Aneurysms Involving the Paravisceral Aorta

Primary mycotic aneurysm of the aorta (MAA) is a rare and potentially life-threatening disease. Endovascular aneurysm repair (EVAR) of MAAs involving the paravisceral aorta has been rarely reported. The purpose of this study is to report our experience with chimney EVAR (CHEVAR) in patients with MAAs involving the paravisceral aorta. We performed a retrospective review of all patients treated with EVAR at our institution during the years 2009-2019. Of those, we identified the patients who were treated with CHEVAR for MAAs. Diagnosis of MAAs was based on clinical presentation, abnormal laboratory results, and a computed tomography scan suggestive of a MAA. The data collected included patient demographics, clinical presentation, the antibiotic regimen before and after the surgery, preoperative imaging, surgical details, and perioperative and long-term morbidity and mortality. During the study period, we performed 54 cases of CHEVARs for aortic aneurysms. Of those, 8 (15%) were performed for mycotic aneurysms involving the visceral segment. Six (75%) were men, and the mean age was 68 years (range: 59-76). All patients were symptomatic at the time of diagnosis, presenting with either back or abdominal pain. A total of 16 visceral vessels (celiac trunk, 2; superior mesenteric artery, 7; right renal artery, 4; and left renal artery, 3) were revascularized with parallel grafts (PGs). Six patients required 2 PGs, 1 patient required 3 PGs, and 1 patient had a single PG inserted. Fifteen (94%) PGs were upward-pointing chimney stent grafts, and 1 was placed in a downward-pointing "periscope" configuration. Eight visceral arteries in 6 patients were sacrificed, either by preoperative occlusion or intentional coverage with the endograft during the procedure. The vessels sacrificed included 4 celiac trunks and 4 renal arteries (3 main branches and 1 accessory renal artery). Technical success was achieved in all patients. One patient expired in the perioperative period. One patient developed an infection-related complication. One patient experienced worsening of his renal function and eventually required dialysis. Of the 4 patients who underwent intentional sacrifice of a kidney, all experienced a moderate decrease in renal function from the baseline ( mean preoperative and postoperative serum creatinine 0.76mg/dL and 1.2mg/dL, respectively, increase of 43%). The mean follow-up was 8months (range: 3-28months). During this period, 2 patients expired, 1 from an aneurysm-related cause. No stent occlusion of the PGs occurred and no reintervention due to endoleaks was required. No patient required explanation of the stent grafts or conversion to an open repair. CHEVAR is a feasible and safe treatment modality for MAAs involving the visceral segment. Occasionally, intentional occlusion of the selected visceral arteries may be required to minimize the risk of gutter endoleaks in this urgent setting. Further follow-up is needed to accurately assess the durability of this repair.