Chimney Endovascular Aneurysm 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.

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.

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

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. A single-center study was conducted of 47 consecutive patients (mean age 72±8years, 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. 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 20.5mm (IQR 16, 24; range 10-48) in group I and 26mm (IQR 17.5, 30; range 8-45) in group II, respectively. During a median time of follow-up of 62months (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. 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.

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.

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.

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.

Initial Outcomes of Patients With Perirenal or Suprarenal Abdominal Aortic Aneurysms Treated in the chEVAS ONE Phase II Trial

The chimney endovascular aneurysm sealing (chEVAS) endograft uses parallel chimney grafting to the renal and visceral vessels with a Nellix EVAS system as an alternative endovascular repair of perirenal and suprarenal aortic aneurysms. The advantages of ChEVAS include a bilateral lower access profile (14F), off the shelf technology, and a potential reduction in the incidence of gutter leaks owing to the polymer filling of the aneurysm sac and aortic neck by the EVAS endobag. We report the early single-institution experience in using this novel technology as a part of the chEVAS ONE (chimney endovascular aneurysm sealing of new expanded indication) trial.

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.

Ongoing migration of chimney endovascular aneurysm sealing

Ongoing migration of chimney endovascular aneurysm sealing

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.

Electrocardiography-gated computed tomography angiography analysis of cardiac pulsatility-induced motion and deformation after endovascular aneurysm sealing with chimney grafts

ObjectiveTo evaluate the proximal stability of the chimney endovascular aneurysm sealing configuration (chEVAS) during the cardiac cycle by investigating the cardiac pulsatility-induced movement and deformation. MethodsWe retrospectively analyzed postoperative electrocardiogram-gated computed tomography angiography scans of 11 chEVAS cases (9 primary chEVAS plus 2 chEVAS-in-chEVAS). ChEVAS procedures were conducted between September 2013 and June 2016. Motion and deformation of the EVAS stents, the chimney grafts, and the stented branch vessels were evaluated during the cardiac cycle using an established combination of image registration and segmentation techniques. ResultsElectrocardiogram-gated computed tomography angiography scans of 11 chEVAS configurations including 22 EVAS stents and 20 chimney grafts were analyzed. The three-dimensional displacement was at most 1.7 mm for both the EVAS stents and the chimney grafts. The maximum change in distance between components was no more than 0.4 mm and did not differ between EVAS-to-EVAS stent and EVAS stent-to-chimney stent (0.2 ± 0.1 mm vs 0.2 ± 0.1 mm; P = .823). The mean change in chimney deflection angle was 1.2 ± 0.7°; the maximum change was greatest for the superior mesenteric artery (SMA) (2.6°). The EVAS stent-to-chimney angles for the left renal artery, right renal artery, and SMA varied on average by 0.7 ± 0.3° (range, 0.4°-1.3°), 1.0 ± 0.3° (range, 0.5°-1.7°), and 0.8 ± 0.4° (range, 0.3°-1.3°), respectively, during the cardiac cycle. The end-stent angles for the left renal artery, right renal artery, and SMA varied on average by 1.7 ± 0.9° (range, 0.5°-3.3°), 1.9 ± 0.8° (range, 0.7°-3.3°), and 1.3 ± 0.4° (range, 0.7°-1.6°), respectively, during the cardiac cycle. Overall, the end-stent angles varied on average by 1.7 ± 0.8° (range, 0.5°-3.3°). ConclusionsThe chEVAS configuration proved to be stable during the cardiac cycle, as demonstrated by minimal cyclical changes in distance between device components and angulation between the EVAS stents and the chimney grafts. The limited deflection angles of the chimney grafts decrease the risk of bending fatigue, but the more apparent change in end-stent angle distal to the chimney graft may raise concerns regarding late branch occlusion or stenosis.

Early and Mid-Term Outcomes of Open Repair, Fenestrated Stent Graft and Chimney Graft in Juxtarenal Abdominal Aortic Aneurysms

Introduction - Juxtarenal abdominal aortic aneurysm (JAAA) is defined as an infrarenal AAA that is adjacent to or involving the lower margin of the renal artery origins1. Recently, promising results have been reported in peer reviewed journals after fenestrated and chimney graft approaches to repair of JAAA2,3. Open repair, fenestrated endovascular aneurysm repair (FEVAR) and chimney endovascular aneurysm repair (Ch-EVAR) are effective methods to treat this condition, but the comparative effectiveness of these treatment modalities is unclear4. Upon completion of a hybrid vascular intervention room at our institution and careful planning and sizing, we started a prospective registry of all JAAA cases performed. Here we present our retrospectively analyzed results, including short and midterm follow-up results in patients with JAAA treated using either endovascular or open repair. Methods - We retrospectively reviewed patients with JAAA (n= 75) who underwent chimney grafts (Ch-EVAR, n = 23), fenestrated stent grafts (FEVAR, n = 20) or open repair (OR, n = 32) between January 2011 and December 2016 at a single institution. Our primary endpoint was peri-operative mortality. Secondary endpoints included renal function impairment, new-onset dialysis, procedural details and postoperative complications. Descriptive statistics are reported as mean ± standard deviation for continuous data and categorical data are presented as number and percentage. Kaplan-Meier analysis was used to estimate freedom from late re-intervention, primary patency of targeted vessel stent grafts and overall survival. Results - There were no statistically significant differences in baseline characteristics among the three groups. Perioperative mortality was not significantly different between groups: 4.3% (1/23) in the Ch-EVAR group, 0% in the FEVAR group and 3.1% (1/32) in the OR group(p = 0.532). Mean follow up time was 36.7 months. There were no statistically significant differences among the three groups in secondary endpoints, except for increased blood loss in the open repair group when compared to the endovascular groups. There were no statistically significant differences in overall survival among groups (p=0.282). Estimated targeted vessel stent patency at 1 and 4 years were 89.5% and 89.5% in the Ch-EVAR group and 93.8% and 93.8% in the FEVAR group, respectively. There were no statistically significant differences in estimated freedom from late re-intervention among groups (82.3% in the Ch-EVAR group, 77.2% in the FEVAR group and 96.4% in the OR group) Conclusion - We were unable to show a ststistically significant difference in outcomes among the treatment options for JAAA repair, which may be due to the size of our series. Nevertheless, our results show that after careful patient selection, we are able to offer our patients good results with fenestrated and chimney graft techniques that are comparable to open surgical procedures, but with a much faster recovery time. All three approaches (Ch-EVAR, FEVAR and open surgery) are effective treatment options for JAAA repair and have comparable short and mid-term outcomes in well-selected patients. Long term follow-up results are needed to determine the optimal management of JAAA. References·Jongkind V, Yeung KK, Akkersdijk GJ, Heidsieck D, Reitsma JB, Tangelder GJ, Wisselink W. Juxtarenal aortic aneurysm repair. J Vasc Surg. 2010;52:760-767·Verhoeven EL, Vourliotakis G, Bos WT, Tielliu IF, Zeebregts CJ, Prins TR, Bracale UM, van den Dungen JJ. Fenestrated stent grafting for short-necked and juxtarenal abdominal aortic aneurysm: An 8-year single-centre experience. Eur J Vasc Endovasc Surg. 2010;39:529-536·Donas KP, Torsello GB, Piccoli G, Pitoulias GA, Torsello GF, Bisdas T, Austermann M, Gasparini D. The protagoras study to evaluate the performance of the endurant stent graft for patients with pararenal pathologic processes treated by the chimney/snorkel endovascular technique. J Vasc Surg. 2016;63:1-7·Katsargyris A, Oikonomou K, Klonaris C, Topel I, Verhoeven EL. Comparison of outcomes with open, fenestrated, and chimney graft repair of juxtarenal aneurysms: Are we ready for a paradigm shift? J Endovasc Ther. 2013;20:159-169

Results of chimney endovascular aneurysm repair as used in the PERICLES Registry to treat patients with suprarenal aortic pathologies

BackgroundThe prevailing evidence calls for using chimney/snorkel endovascular repair (ch-EVAR) with one or two chimney grafts. No studies up to now focus on its applicability and results for the treatment of suprarenal aortic pathologies (SRAP). Hence, we evaluated the clinical and radiologic results of ch-EVAR treatment for SRAP placing three or more chimney grafts within the PERICLES Registry. MethodsData from 517 patients suffering complex aortic pathologies treated by ch-EVAR between 2008 and 2014 at 13 European and U.S. centers were retrospectively reviewed and analyzed. ResultsSixty-seven ch-EVAR-treated patients (12.9% of the entire PERICLES cohort) presented SRAP (83.5% elective, 16.5% urgent). The majority of patients (95.5%) received three chimney grafts; four patients received four chimney grafts. The Endurant device was the most commonly used (35.8%) followed by the Zenith abdominal endograft (19.4%). Overall, 204 chimney grafts were placed (56.7% covered self-expandable, 40.3% covered balloon-expandable stents, and 10.4% bare metal balloon-expandable stents). At a median follow-up of 24 months (range, 0.1-67.0 days), 30-day mortality was 6.1% (4 patients), and the overall mortality was 16.4% (11 patients). Overall survival was 87.4% (range, 79.5%-96.0%) at 1 year, 81.8% (range, 72.2%-92.2%) at 2 years and thereafter. Type IA endoleak was noted in nine patients (13.4%) intraoperatively and successfully treated in seven cases (97.1% technical success). Aneurysm sac diameter significantly decreased from 70.5 ± 19.3 mm to 66.9 ± 20.6 mm (P < .001) at last follow-up. Ischemic stroke or transient ischemic attack were noted in two patients (2.9%). Chimney occlusion was detected in six renal arteries (9.5%) and two superior mesenteric arteries (3.2%). No patients required chronic hemodialysis. All occluded superior mesenteric artery grafts were successfully rescued using endovascular approaches. ConclusionsThe midterm use of ch-EVAR for the treatment SRAP seems to be safe, highlighting its applicability for the treatment of rupture threatening pathologies and seal zone lengthening as in type IA endoleaks after EVAR. However, the incidence of type IA endoleaks, chimney graft occlusions, and ischemic stroke rates is higher compared with the prevailing single chimney evidence. Longer follow-up with more cases is needed to establish the exact performance of this treatment in SRAP.

CTA Assessment of Midterm Morphological Changes to Chimney Grafts Used in the Treatment of Juxtarenal Aortic Aneurysms

Purpose: To evaluate chimney stent-graft position and morphological changes of the aneurysm sac as visualized by postoperative computed tomography angiography (CTA) over a minimum 24-month follow-up period. Materials and Methods: Twenty-one patients (mean age 75.7±8.6 years; 20 men) with juxtarenal aortic aneurysms who underwent successful chimney endovascular aneurysm repair (ch-EVAR) with the Endurant stent-graft and had 2 postoperative CTAs separated by at least 24 months were included in the study. CTA-based measurements of aortic stent-graft migration, target vessel angle, and chimney angle were compared between the serial scans. Results: During a mean follow-up of 34.9 months (range 24–69.2), the mean migration of the aortic stent-grafts was under 5 mm (2.76±2.4 mm). The average migration distance per year was 1.15 mm. The aneurysm diameter reduced a mean 3.25 mm (p=0.048). The right renal artery angle moved significantly upward 6.72° (p=0.025), while the right renal chimney stent-graft moved significantly downward 7.83° (p=0.042). The left renal artery angle also moved upward 1.87° (p=0.388) and the corresponding chimney moved downward 5.68° (p=0.133). During the study period, no type I/III endoleak or chimney occlusion was observed. Conclusion: Midterm morphometric assessment of ch-EVAR using CTA showed significant aneurysm sac shrinkage and a stable 3-year position of the abdominal devices, with the mean downward migration of the aortic stent-graft being <5 mm in the majority of cases. The chimney grafts seem to be prone to take an oblique rather than parallel configuration during follow-up. However, there was no relevant clinical consequence related to this phenomenon.

Chimney Endovascular Aneurysm Repair is now Officially Recommended as an Alternative Treatment Option Based on the New European Society for Vascular Surgery Abdominal Aortic Aneurysm Guidelines of 2019: Do We Want to Keep Looking at the Tree and Not the Forest?

We read the commentary from Alric and Canaud1Alric P. Canaud L. Is chimney EVAR an acceptable endovascular technique?.EJVES Short Rep. 2019; 42: 43https://doi.org/10.1016/j.ejvssr.2019.01.001Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar regarding our case of a symptomatic patient unfit for open repair symptomatic with persistent gutter related type Ia endoleak after chimney endovascular aneurysm repair (ch-EVAR).2Ballesteros-Pomar M. Taneva G.T. Austermann M. Fernández-Samos R. Torsello G. Donas K.P. Successful management of a type B gutter related endoleak after chimney EVAR by coil assisted onyx embolisation.EJVES Short Rep. 2019; 42: 38-42https://doi.org/10.1016/j.ejvssr.2018.12.002Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar The goal of our case presentation was to provide information about possible solutions for suboptimal performance, as a lesson learned after 10 years of clinical experience and treatment of more than 250 cases by ch-EVAR.3Donas K.P. Lee J.T. Lachat M. Torsello G. Veith F.J. Dalman R.L. et al.Collected world experience about the performance of the snorkel/chimney endovascular technique in the treatment of complex aortic pathologies: the PERICLES registry.Ann Surg. 2015; 262: 546-552https://doi.org/10.1097/SLA.0000000000001405Crossref PubMed Scopus (221) Google Scholar, 4Donas K.P. Torsello G.B. Piccoli G. Pitoulias G.A. Torsello G.F. Bisdas T. et al.The PROTAGORAS study to evaluate the performance of the Endurant stent graft for patients with pararenal pathologic processes treated by the chimney/snorkel endovascular technique.J Vasc Surg. 2016; 63: 1-7https://doi.org/10.1016/j.jvs.2015.07.080Abstract Full Text Full Text PDF PubMed Scopus (115) Google Scholar As the authors published when they reported on the role of physician modified endografts “to break the rules you must first master them.”5Canaud L. Gandet T. Ozdemir B.A. Sfeir J. Alric P. Commentary: physician-modified thoracic stent-graft: to break the rules you must first master them.J Endovasc Ther. 2018; 25: 464-465https://doi.org/10.1177/1526602818779394Crossref PubMed Scopus (1) Google Scholar And, in this context, we believe that presentation of successful management of challenging cases with persistent post-operative flow to the aneurysm sack is of particular importance, having as a sustained goal of optimising the outcome in favour of the patient. The authors are wondering whether ch-EVAR is in general, an alternative option. The answer could be very easily given from recommendation 97 of the European Society for Vascular Surgery (ESVS)'s newest guidelines regarding juxtarenal aneurysms.6Wanhainen A. Verzini F. Herzeele I Van Allaire E. Bown M. Cohnert T. et al.European Society for Vascular Surgery (ESVS) 2019 clinical practice guidelines on the management of abdominal aorto-iliac artery aneurysms.Eur J Vasc Endovasc Surg 2019. 2018; https://doi.org/10.1016/j.ejvs.2018.09.020Abstract Full Text Full Text PDF Scopus (1165) Google Scholar It is stated that ch-EVAR can be considered as an alternative option when fenestrated endografting (f-EVAR) is not indicated or not available. The level of evidence (C) is the same as for f-EVAR,6Wanhainen A. Verzini F. Herzeele I Van Allaire E. Bown M. Cohnert T. et al.European Society for Vascular Surgery (ESVS) 2019 clinical practice guidelines on the management of abdominal aorto-iliac artery aneurysms.Eur J Vasc Endovasc Surg 2019. 2018; https://doi.org/10.1016/j.ejvs.2018.09.020Abstract Full Text Full Text PDF Scopus (1165) Google Scholar and our case is in full alignment with this recommendation. There is no evidence in the new guidelines supporting other alternative therapies rather than chimney grafts as the authors of the commentary suggested. In summary, the use of chimney grafts is no longer a matter of faith but a fact. The evidence in the literature supports its complementary role for the treatment of juxtarenal aneurysms and in agreement with that the ongoing ENCHANT Study as a fully prospective multicentre trial of ch-EVAR (clinicaltrials.gov identifier: NCT03320252) will provide further evidence bringing the technique to a higher level of evidence (B) than f-EVAR (C). Do we want to keep looking at the tree and not the forest?

Assessment of changes in stent graft geometry after chimney endovascular aneurysm sealing

BackgroundChimney endovascular aneurysm sealing (ch-EVAS) could potentially minimize gutter-associated endoleaks in patients with juxtarenal abdominal aortic aneurysms resulting from the use of the conformable endobags surrounding the chimney stent grafts (ch-SGs). The aim of the present study was to quantify the (non)apposition of the endobags in the proximal aortic neck, migration of the endograft stent frames, and changes in geometry of the ch-SGs during the follow-up period. MethodsThe prospective data from 20 patients undergoing elective ch-EVAS were retrospectively reviewed. The aortic anatomy was analyzed on preoperative and postoperative computed tomography scans. The (non)apposition of the endobags in the aortic neck, Nellix (Endologix, Irvine, Calif) stent frame migration, and chimney graft geometry and migration were assessed. ResultsThe median preoperative infrarenal neck length was 4.0 mm (interquartile range [IQR], 0-6.0 mm). The median seal length in the juxtarenal aortic neck at the first follow-up was 23.0 mm (IQR 18.0-30.8 mm). Five type IA endoleaks were identified on postoperative imaging; one at 1 month and four newly diagnosed at 1 year. Of these five type IA endoleaks, two were type Is1 (not extending into the aneurysm sac) and did not need reintervention and other three were type Is2 (extending into the aneurysm sac). One of these patients died of malignancy before reintervention could be performed. Bilateral ch-SG occlusions in one patient were documented at the 1-month follow-up (patient needed hemodialysis) and two patients with a new single ch-SG occlusion were found at the 1-year follow-up. No reinterventions were performed for the ch-SG occlusions. An occluded Nellix stent frame in one patient was treated with femorofemoral crossover bypass. Kaplan-Meier estimate of reintervention-free survival was 85.0% after 1 year. Migration ≥5 mm of the proximal end of the Nellix stent frames was observed in 20.0% of the patients, but no reintervention was performed at the 1-year follow-up. Imaging showed 20.1% of the available sealing surface was not used, and the nonapposition surface increased to 30.6% of the preoperative aortic neck surface at 1 year. Median migration was 3.5 mm (IQR, 2.4-5.0 mm) and 3.1 mm (IQR, 2.0-4.8 mm) for the left and right proximal end of the Nellix stent frames, respectively, and was 3.0 mm (IQR, 2.2-4.8 mm) for the proximal end of the ch-SGs at 1 year of follow-up. ConclusionsSubstantial distal migration of the Nellix endograft and positional changes of the ch-SGs in the juxtarenal aortic neck were observed at 1 year of follow-up, resulting in a 25.0% type IA endoleak rate, with three of these type IA endoleaks extending into the aneurysm sac. The reintervention-free survival rate was 85.0% at 1 year in this cohort of 20 patients. Careful follow-up after ch-EVAS is advised because changes are often subtle. The authors have stopped the ch-EVAS procedure so far. Long-term follow-up data on the stability of the Nellix endograft and the consequences of migration on ch-SGs is required before this technique should be used in clinical practice.