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Background: A considerable number of patients with abdominal aortic aneurysms (AAA) is not eligible for standard endovascular repair. These complex cases require alternative surgical approaches including the readily available chimney graft endovascular aneurysm repair (Ch-EVAR) or sealing (Ch-EVAS). The optimal configuration for Ch-EVAR or Ch-EVAS is important for success but not yet known. Objective: The aim of the present study was to analyze current data of the outcomes of in-vitro chimney graft treatment in complex AAA. Methods: A systematic review following PRISMA guidelines was conducted including studies reporting on gutter size, main graft compression, and chimney graft compression in in-vitro configurations. Results: The search resulted in 285 articles. 11 studies considering 219 individual tests could be included. Gutter size was comparable between Ch-EVAR and Ch-EVAS configurations. In Ch-EVAR set-ups, the deployed BECG were Advanta V12, VIABAHN®, and BeGraft. One type of SECG was used: VIABAHN®. The four types of main grafts (MG) deployed were: Endurant™ I/II; EXCLUDER Conformable AAA Endoprosthesis and AAA Endoprosthesis, and AFX™ Endovascular AAA Delivery System. In the EVAS-configurations, the Nellix® EVAS system was deployed. In general, SECG presented smaller gutters with higher chimney graft compression. 30% main grafts oversizing seems to give the smallest gutters without high risk of infolding of MG. Oversizing, EndoAnchors, and secondary endobag filling (in Ch-EVAS) reduced gutter sizes. CG ballooning during the entire polymer injection in Ch-EVAS prevented CG compression. Conclusion: In-vitro investigations provide insight in optimal Ch-EVAR and Ch-EVAS configurations for simulated complex AAA repair. The findings above might aid physicians in their planning to potential CG set-ups and can be used in future research to refine the most optimal configuration for chimney graft technique in complex AAA. [ABSTRACT FROM AUTHOR]

Steep aortic arch (such as Type III arch) and small angle between the chimney artery and aortic arch are two anatomic conditions suitable for chimney grafts (CGs). The more the number of chimneys, the higher the incidence of endoleak and branch occlusion; thus, the triple-chimney technique should be avoided unless the lesion involves zone 0 and no other better option is available, or a pending rupture is present and requires emergent repair. For the oversize of multiple chimneys, we suggest that the aortic stent and chimney stent should be increased by 5%, respectively, on the basis of single chimney. Moreover, the direction of the chimney stent is decided by the relative position of the proximal tear in patients with dissection. When the tear is located in the anterior segment, the chimney graft should be deployed behind the aortic stent graft, close to the posterior wall of the thoracic aorta, and in front of the aortic stent grafts when the tear is located in the posterior segment. In conclusion, if the endoleak is small and the patient's condition is stable with no obvious discomfort, for most of the patients, the endoleak will disappear spontaneously in the follow-up. If the endoleak is large, microcoil could be implanted through the narrow and long gap to block the endoleak under the guidance of ultrasound. CGs technique needs to be scrutinized continuously as new data emerge. Special configurations of aortic and chimney endograft need to be developed to better treat aortic pathologies involving supra-arch branches.

A 63-year-old man presented for the treatment of abdominal aortic aneurysm in the setting of bilateral internal iliac artery compromise from prior peripheral arterial disease treatments. The inferior mesenteric artery (IMA) measured 5 mm. Patient underwent coronary artery stenting 6 months prior and experienced left leg claudication. He underwent endovascular aneurysm repair with chimney IMA grafting and a femorofemoral bypass with uneventful recovery. At 1 year, computed tomography angiogram shows no flow in the aneurysm sac, and his left leg claudication resolved. Endovascular aneurysm repair with chimney IMA grafting for colonic perfusion preservation is a reasonable alternative to open surgical repair with IMA reimplantation in high-risk patients.

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 7 days 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 24 months (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. [ABSTRACT FROM AUTHOR]

Thoracoabdominal aneurysms pose technical challenges for endovascular repair due to involvement of visceral and renal vessels. We report a case series of four patients diagnosed with thoracoabdominal aneurysm who underwent complex endovascular repair with Fenestrated Device and chimney grafts (FEVARCh). FEVARCh is a technically feasible approach for repair of thoracoabdominal aneurysms that involve renal, superior mesenteric, and celiac arteries for patients not appropriate for open surgical repair. Further studies are needed to understand the implications of resultant Type 1a endoleaks and strategies to minimize the displacement of the main body graft with adjunct chimneys. [ABSTRACT FROM AUTHOR]

Background: This study aimed to share the experience in applying the chimney graft technique combined with embolization for treating aortic arch rupture under emergency conditions and evaluating early-term results in these patients.Methods: This study retrospectively included patients with ruptured aortic arch lesions who received the chimney graft technique combined with embolization between March 2016 and March 2021. The primary endpoint was a technical success, deemed as successful stent graft deployment to the planned location, patency of the target branch vessel, and absence of significant type I endoleak. The secondary endpoint was clinical success defined with the size of false lumen in follow-up remaining unchanged or decreasing over time, 30-day mortality, complication, and primary patency of chimney graft.Results: This study included 12 patients (age, 61 ± 12 years; male, 83%). Five patients (42%) received single chimney, one patient (8%) received double chimney, and six patients (50%) received triple chimney. Intraoperative type I endoleak occurred in six patients (50%) who underwent endovascular embolization in the primary operation. Post-operative type I endoleak, evaluated by computed tomography angiography examination following the primary operation, occurred in seven patients (58%), including one patient who received endovascular embolization two times. All patients with post-operative type I endoleak were successfully re-treated using coil and Onyx glue within 1 week, and the median length of stay was 22 ± 11 days (range: 7–44 days). Overall technical success was 100%. Eleven patients had completed their follow-up (median, 12 months, range: 1–34 months), and one patient was out of contact. The 30-day mortality was 9% (1/11, post-operative death of a patient with cerebral hemorrhage). No major complications and no chimney compression, migration, occlusion, or stenosis were recorded during follow-up. Seven patients (58%) have ≥6 months of clinical follow-up time with appropriate imaging. In four (57%) of these patients, diameter stabilization was detected, whereas three (43%) experienced significant reduction (≥5 mm).Conclusion: The patients in this study had satisfactory early-term outcomes. The chimney graft technique combined with coil and Onyx glue embolization may be a safe and effective treatment for ruptured aortic arch lesions under emergency conditions.

Objective: To quantify dynamic gutter phenomena and endograft deformations during double chimney thoracic endovascular aortic repair (ch-TEVAR) in a physiological model of the thoracic aorta subjected to pulsatile haemodynamic conditions., Methods: Two in vitro procedures revascularizing the brachiocephalic trunk and left common carotid artery were performed representing both balloon-expandable (BE, Ankura-BeGraft) and self-expandable (SE, Ankura-Viabahn) double ch-TEVAR configurations. Retrospectively gated computed tomography (CT) was used to evaluate endograft behaviour. Device interactions were characterised according to gutter volume, gutter surface deviation, and endograft deformation (D-ratio) at end-diastolic and peak-systolic aortic pressure., Results: Use of BE chimney grafts resulted in three times total gutter volume compared to SE chimney grafts. Gutter volumes were observed to vary dynamically between the end-diastolic and peak-systolic phases of the cardiac cycle, with the most substantial change associated with the BE configuration. Chimney graft deformations were dependent on device type, with SE devices exhibiting up to twice the deformation as BE devices. When adjacent, SE chimney grafts were observed to support each other, and thus tended towards a more consistently circular shape., Conclusion: Gutter and chimney graft behaviour were dependent on device type, and exhibited both spatial and temporal variability. This study emphasises notable differences between BE and SE double ch-TEVAR configurations which should be considered when evaluating risk of endoleak. The findings reported here also support the use of gated CT to better identify device-related complications with ch-TEVAR, and can be used in the design of next generation devices., Competing Interests: Declaration of conflicting interestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Authors Jakub Kwiecinski, Raman Uberoi, Mohammed Hadi, Christopher P. Cheng, and Zhong You declare that they have no conflict of interest.

Purpose: To assess the incidence of migration after endovascular aneurysm sealing (EVAS) in conjunction with chimney grafts (chEVAS) for repair of abdominal aortic aneurysms (AAAs). Materials and Methods: A retrospective, observational cohort study was conducted of 31 patients (mean age 75.7 years; 27 men) treated for juxtarenal AAA between April 2013 and December 2018 at single centers in New Zealand and the Netherlands. The majority of patients received >1 chimney graft (13 single, 13 double, and 5 triple) during chEVAS. Six patients had only the first postoperative scan, so the migration analysis was based on 25 patients. Results: Median seal length assessed on the first postoperative computed tomography scan was 36.5 mm. The assisted technical success rate was 93.5% with 2 technical failures. Median time to final imaging follow-up was 17 months in 25 patients. At the latest follow-up, there were no cases of caudal migration >10 mm. Freedom from caudal movement of 5 to 9 mm was estimated as 86.1% at 1 year and 73.9% at 2 years; freedom from clinically relevant migration (movement requiring reintervention) was 100% at both time intervals. However, at 3 years there were 2 cases of caudal movement of 5 to 9 mm and a type Ia endoleak warranting reintervention. No correlation between migration and aneurysm growth (p=0.851), endoleak (p=0.562), or the number of chimney grafts (p=0.728) was found. During follow-up, 2 patients (7%) had aneurysm rupture and 10 (33%) had reinterventions. Eight patients (27%) died; 2 were aneurysm-related (7%) and due to the consequences of a reintervention. Conclusion: In the 2 years following chEVAS, there was no caudal migration >10 mm, but nearly a quarter of patients had caudal movement of 5 to 9 mm. A trend was observed toward ongoing migration that required intervention at 3-year follow-up. chEVAS is technically challenging and should be considered only for patients with no viable alternative treatment option. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the midterm outcomes of thoracic endovascular aortic repair (TEVAR) using chimney grafts (ch-TEVAR) or thoracic stent-grafts with fenestrations made on the back table (f-TEVAR) to treat thoracic aortic dissection (TAD) and thoracic aortic aneurysm (TAA). Materials and Methods: A retrospective analysis was conducted of 474 consecutive patients (mean age 62.3±10.7 years; 346 men) treated with either f-TEVAR (n=110) or ch-TEVAR (n=364) for 352 TADs (81 f-TEVAR and 271 ch-TEVAR) or 122 TAAs (29 f-TEVAR and 93 ch-TEVAR) from 2008 to 2016. The primary endpoints at 30 days and during follow-up were overall mortality, aorta-related mortality, and major complications. The secondary endpoints were endoleak and reintervention. The patency of the target branches, cost of hospitalization, and the use of antiplatelet drugs were also analyzed. Results: Intraoperative type I endoleaks were treated in 69 (14.6%) cases (4 f-TEVAR and 65 ch-TEVAR, p<0.01) to achieve 100% technical success. Four (0.8%) patients died within 30 days [1 (0.9%) f-TEVAR and 3 (0.8%) ch-TEVAR]. Perioperative cerebral ischemia (1 fatal stroke) occurred in 9 (1.9%) patients: (1 f-TEVAR and 8 ch-TEVAR, p=0.39). During the mean follow-up of 50.6±20.0 months (49.5±18.3 months in f-TEVAR and 50.9±20.6 months in ch-TEVAR), 11 (2.3%) patients died of an aorta-related event. Type I endoleak was present in 40 (8.4%) patients (1 f-TEVAR and 39 ch-TEVAR, p<0.01). Eleven (2.3%) patients experienced stent-graft migration and 13 (2.7%) had a retrograde dissection. One hundred (16.9%) of the 593 branch stents occluded (4/75 in the f-TEVAR group and 96/518 in the ch-TEVAR group, p<0.01). The branch reintervention rate was 7.2% (34/474). The f-TEVAR group had a significantly higher probability of freedom from branch occlusion (92%) than the ch-TEVAR group (83%, p=0.007). Conclusion: Off-the-shelf techniques employing chimney grafts and homemade fenestrations are both suitable options for TAD and TAA involving the supra-aortic branches, with a low incidence of reintervention. Fenestrated TEVAR seems to have more favorable short- and midterm outcomes. Further study of these off-the-shelf techniques for aortic arch repair is warranted. [ABSTRACT FROM AUTHOR]

Purpose: To report the use of the Nellix endovascular aneurysm sealing (EVAS) system in the management of proximal stent-graft collapse associated with thrombosis following endovascular aneurysm repair (EVAR).Case Report: A 76-year-old man was admitted for proximal collapse of an aortic extension following bifurcated AFX stent-graft implantation associated with chimney grafts in both renal arteries and the superior mesenteric artery 1 month prior. Imaging identified thrombosis of the aortic stent-graft and the iliac limbs. A Nellix EVAS was placed into the AFX stent-graft to recanalize the aneurysm lumen and address the aortic thrombosis. There was no endoleak, and the renovisceral chimney stent-grafts remained patent over a follow-up of 25 months.Conclusion: While further studies are required to generalize its use, EVAS appears to be feasible in the management of aortic stent-graft collapse. [ABSTRACT FROM AUTHOR]

Purpose: To investigate in an in vitro model if secondary endobag filling can reduce gutter size during chimney endovascular aneurysm sealing (chEVAS).Materials and Methods: Nellix EVAS systems were deployed in 2 silicone juxtarenal aneurysm models with suprarenal aortic diameters of 19 and 24 mm. Four configurations were tested: EVAS with 6-mm balloon-expandable (BE) or self-expanding (SE) chimney grafts (CGs) in the renal branches of both models. Balloons were inflated simultaneously in the CGs and main endografts during primary and secondary endobag filling and polymer curing. Computed tomography (CT) was performed immediately after the primary and secondary fills. Cross-sectional lumen areas were measured on the CT images to calculate gutter volumes and percent change. CG compression was calculated as the reduction in lumen surface area measured perpendicular to the central lumen line. The largest gutter volume and highest compression were presented per CG configuration per model.Results: Secondary endobag filling reduced the largest gutter volumes from 99.4 to 73.1 mm3 (13.2% change) and 84.2 to 72.0 mm3 (27.6% change) in the BECG configurations and from 67.2 to 44.0 mm3 (34.5% change) and 92.7 to 82.3 mm3 (11.2% change) in the SECG configurations in the 19- and 24-mm models, respectively. Secondary endobag filling increased CG compression in 6 of 8 configurations. BECG compression changed by -0.2% and 5.4% and by -1.0% and 0.4% in the 19- and 24-mm models, respectively. SECG compression changed by 10.2% and 16.0% and by 7.2% and 7.3% in the 19- and 24-mm models, respectively.Conclusion: Secondary endobag filling reduced paragraft gutters; however, this technique did not obliterate them. Increased CG compression and prolonged renal ischemia time should be considered if secondary endobag filling is used. [ABSTRACT FROM AUTHOR]

Purpose: To analyze the results of isolated left subclavian artery (LSA) revascularization during thoracic endovascular aortic repair (TEVAR) using carotid-subclavian bypass (CSbp) or chimney grafts (CGs).Methods: A retrospective multicenter, observational study identified 73 patients (mean age 68±13 years, range 22-87; 56 men) with acute or chronic thoracic aortic lesions who underwent TEVAR with isolated LSA revascularization using either CSbp (n=42) or CGs (n=31) from January 2010 and February 2017. Primary endpoints were TEVAR-related mortality, postoperative stroke, freedom from type Ia endoleak, and LSA patency.Results: Primary technical success was achieved in all cases. Early TEVAR-related mortality was 4.2% (CSbp 2% vs CG 6%, p=0.571). Two (3%) patients had major ischemic strokes (one in each group). Mean follow-up was 24±21 months (range 1-72; median 15). Estimated freedom from TEVAR-related mortality was 93%±3% (95% CI 84.3% to 97.0%) at 12 and 36 months, with no significant difference between CSbp and CG (p=0.258). Aortic reintervention did not differ between the groups (CSbp 5% vs CG 6%, p=0.356); nor did freedom from type Ia endoleak (CSbp 98% vs CG 87%, p=0.134). Gutter-related endoleaks occurred in 4 (13%) CG patients, but none of the patients experienced sac enlargement or the need for reintervention and none died. Primary patency of the LSA was 100% for the entire group during the observation period.Conclusion: In our experience, LSA revascularization proved most satisfactory and equally effective with both the CSbp and CG techniques, without discernible differences at midterm follow-up. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this retrospective analysis was to evaluate the performance of the chimney (ch) technique in the treatment of type Ia endoleaks after standard endovascular aneurysm repair (EVAR).Methods: Between January 2008 and December 2014, 517 chEVAR procedures were performed in 13 US and European vascular centers (PERICLES registry). Thirty-nine patients (mean age 76.9±7.1 years; 33 men) were treated for persistent type Ia endoleak and had computed tomography angiography or magnetic resonance angiography follow-up at >1 month. Endurant abdominal stent-grafts were used in the 20 cases. Single chimney graft placement was performed in 18 (46%) patients and multiple in 21 (54%). Overall, 70 visceral vessels were targeted for revascularization.Results: Technical success was achieved in 35 (89.7%) cases; 3 persistent type Ia endoleaks and 1 chimney graft occlusion were detected within the first 30 days. Thirty-day mortality was 2.6%. Two other deaths (not aneurysm related) occurred during a mean follow-up of 21.9 months (0.23-71.3). Primary patency of the chimney grafts was 94.3% at 36 months. In a subgroup analysis comparing Endurant to other stent-grafts, no significant differences were observed regarding persistent endoleak [1/20 (5%) vs 2/19 (11%), p=0.6] or reintervention [1/20 (5%) vs 0/19 (0%)].Conclusion: The present series demonstrates that chEVAR in the treatment of post-EVAR type Ia endoleaks has satisfactory results independent of the abdominal and chimney graft combinations. Midterm results show that chEVAR is an effective method for treating type Ia endoleaks. [ABSTRACT FROM AUTHOR]

Purpose: To assess the dynamic behavior of chimney grafts during the cardiac cycle. Methods: Three chimney endovascular aneurysm repair (EVAR) stent-graft configurations (Endurant and Advanta V12, Endurant and Viabahn, and Endurant and BeGraft) were placed in silicone aneurysm models and subjected to physiologic flow. Electrocardiography (ECG)-gated contrast-enhanced computed tomography was used to visualize geometric changes during the cardiac cycle. Endograft and chimney graft surface, gutter volume, chimney graft angulation over the center lumen line, and the D-ratio (the ratio between the lengths of the major and minor axes) were independently assessed by 2 observers at 10 time points in the cardiac cycle. Results: Both gutter volumes and chimney graft geometry changed significantly during the cardiac cycle in all 3 configurations (p<0.001). Gutters and endoleaks were observed in all configurations. The largest gutter volume (232.8 mm3) and change in volume (20.7 mm3) between systole and diastole were observed in the Endurant-Advanta configuration. These values were 2.7- and 3.0-fold higher, respectively, compared to the Endurant-Viabahn configuration and 1.7- and 1.6-fold higher as observed in the Endurant-BeGraft configuration. The Endurant-Viabahn configuration had the highest D-ratio (right, 1.26-1.35; left, 1.33-1.48), while the Endurant-BeGraft configuration had the lowest (right, 1.11-1.17; left, 1.08-1.15). Assessment of the interobserver variability showed a high correlation (intraclass correlation >0.935) between measurements. Conclusion: Gutter volumes and stent compression are dynamic phenomena that reshape during the cardiac cycle. Compelling differences were observed during the cardiac cycle in all configurations, with the self-expanding (Endurant-Viabahn) chimney EVAR configurations having smaller gutters and less variation in gutter volume during the cardiac cycle yet more stent compression without affecting the chimney graft surface. [ABSTRACT FROM AUTHOR]

Purpose: To report the results of the ASCEND Registry of cases involving endovascular aneurysm sealing (EVAS) in combination with chimney grafts (chEVAS) for the treatment of para- and juxtarenal aortic aneurysms (AAA).Methods: A retrospective, multicenter registry established in 8 vascular centers between 2013 and 2016 recorded the treatment results and follow-up of chEVAS procedures for nonruptured AAAs; data were analyzed using standardized outcome measures. In the observation period, 154 patients (mean age 72.3±7.7 years; 124 men) underwent elective treatment for de novo juxtarenal and pararenal aneurysms and formed the study group.Results: Sixty-two (40.3%) of the cohort were treated using a single parallel graft, 54 (35.1%) with double chimneys, 27 (17.5%) with triple chimneys, and 11 (7.1%) with 4 chimneys. The 30-day mortality was 2.8%, and there were 4 perioperative strokes (1 fatal). At 1 year, the freedom from all-cause mortality was 89.8% and the freedom from aneurysm-related mortality was 94.3%. There were 3 endoleaks within 90 days of the procedure, one type Ia and 2 type Ib. The freedom from type Ia endoleaks was 95.7% at 1 year. There were no types II or III endoleaks in this series; the freedom from all endoleaks was 94.2% at 1 year. Freedom from reintervention at 1 year was 89.2%. Target vessel patency rates at 1 year were 97.7%, 99.3%, 100%, and 100% for the left renal, right renal, superior mesenteric artery, and celiac axis stents, respectively.Conclusion: The ASCEND Registry supports a proof of concept for the use of polymer technology and EVAS with parallel grafts in managing patients with complex aortic disease. The future role of chEVAS will be defined by studies that assess mid- to long-term durability. [ABSTRACT FROM AUTHOR]

Purpose: To determine how many endovascular aneurysm sealing (EVAS) procedures with/without off-label use of chimneys (ChEVAS) could have been performed in a cohort of patients who had undergone fenestrated endovascular aneurysm repair (FEVAR).Methods: Sixty patients (median age 76.3 years; 54 men) who underwent FEVAR in our institution between 2013 and 2015 were selected for the study. The median aneurysm diameter was 62.0 mm (interquartile range 59.3, 69.0). Preoperative computed tomography angiograms (CTA) were anonymized and sent to 2 physicians with experience of more than 40 ChEVAS interventions. These ChEVAS planners were blinded to the study purpose and asked to agree upon an EVAS/ChEVAS plan. The primary outcome was the percentage of the FEVAR patients in whom an EVAS/ChEVAS was technically possible. The secondary outcomes were a comparison of seal zones, number of target vessels, and device cost.Results: An EVAS-based intervention would have been technically possible in 56 (93.3%) of the FEVAR patients. The median proximal aortic seal zone was significantly more distal in the EVAS/ChEVAS procedures vs the FEVAR cases (zone 8 vs zone 7, p<0.001) and fewer target vessels were involved (median 2 vs 3, p<0.001). The cost of the EVAS/ChEVAS device was 66% of the FEVAR device. Planners would not currently advocate an EVAS-based intervention in 43 (76.8%) of these 56 patients due to concerns regarding the risk of migration associated with the lumen thrombus ratios observed.Conclusion: EVAS is technically feasible in the majority of patients undergoing FEVAR in our institution but currently advocated in only 23.2%. The seal zone was more distal, fewer target vessels were involved, and the device cost was lower in the planned EVAS/ChEVAS interventions. [ABSTRACT FROM AUTHOR]

Background: The chimney graft (CG) technique has been proposed as a complete endovascular supra-aortic branch reconstruction for aortic pathologies. Due to the rapid growth of thoracic endovascular aortic repair (TEVAR) in China, we aimed to investigate the current data of the CG technique in this most populous country. Methods: Studies of supra-aortic branch reconstruction using the CG technique from Chinese centers were collected and analyzed. Results: A total of 294 patients from Chinese centers who underwent TEVAR with CGs were included. There were 301 CGs performed, with a technical successful rate of 97.7%. The rate of early type I endoleaks was 7.1%, and the patency rate of the CGs was desirable. Balloon-expandable bare CGs were significantly associated with good early outcomes and a low rate of endoleaks. Conclusion: Current data from China revealed positive outcomes using CGs for supra-aortic branch reconstruction. Balloon-expandable bare CGs may be the first choice according to the data available but should be considered with caution. [ABSTRACT FROM AUTHOR]

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Purpose: To describe 2 patients with a distally migrated endograft causing a type Ia endoleak and treatment with a proximal cuff and chimney grafts that required EndoAnchors to finally seal the leak.Case Report: Two men, ages 86 and 72 years, presented with stent-graft migration and type Ia endoleak at 5 and 15 years after endovascular repair, respectively. Both were treated with a proximal cuff in combination with a chimney graft to the left renal artery. In both cases, the type Ia endoleak persisted, likely due to gutter formation. Both patients were treated in the same setting with EndoAnchors that instantly resolved the endoleak. At 1-year follow-up, there was no recurrent endoleak or migration, with patent chimney grafts and renal arteries and stable renal function.Conclusion: EndoAnchors may effectively resolve a persistent type Ia endoleak arising from gutter formation after placement of a proximal cuff and chimney grafts. [ABSTRACT FROM AUTHOR]

Objective Chimney endovascular aneurysm repair (Ch-EVAR) is a cheap and immediately available method for treatment of juxtarenal aortic aneurysms (JRAAs). The aim of this study was to report experiences and results with balloon expandable stent (BES) for Ch-EVAR. Methods From January 2008 to June 2013 (mean time, 26 ± 13 months), 42 patients who underwent Ch-EVAR were retrospectively reviewed. All patients were thought to be at high risk for open surgery and were unsuitable (because of financial issues and fear of delays) for fenestrated endovascular aneurysm repair (FEVAR). Results 42 patients (35 males; mean age 71 ± 7 years) underwent chimney procedures for 56 renal arteries with 70 BESs (59 hippocampus and 11 genesis). Median follow up was 26 months (range 6–64 months). Primary technical success was 100%. Thirty day mortality was 0%. Completion angiography showed that eight cases (19%) had a type I endoleak. The 6 month follow up CT scans demonstrated three cases with complete regression of endoleak, two cases without aneurysmal growth, and three cases with an increase in aneurysmal diameter of less than 10 mm. Three patients had contrast induced nephropathy (CIN) after Ch-EVAR, two of whom had acute renal failure (ARF) and continue to require hemodialysis. Two deaths occurred during follow up, both unrelated to the aorta: one with a hemispheric stroke at 6 months and one with respiratory failure at 12 months. Therefore, the overall follow up mortality was 5%. Occlusion of one chimney stent occurred 3 months after the procedure, meaning renal artery patency rate was 98%. The aneurysm diameter reduced from 74 ± 9 mm to 64 ± 10 mm during follow up ( p < .05). Conclusion Ch-EVAR can be used to treat JRAAs with suitable anatomical conditions. However, complications of type I endoleak were not uncommon, and, therefore, further studies are required to prove its efficiency for JRAAs. [ABSTRACT FROM AUTHOR]

After abdominal aortic aneurysm repair, progressive degeneration of the aneurysm can be challenging to treat. Multiple comorbidities and previous operations place such patients at high risk for repeat surgery. Endovascular repair is a possible alternative; however, challenging anatomy can push the limits of available technology. We describe the case of a 71-year-old man who presented with a 5.3-cm pararenal aneurysm 4 years after undergoing open abdominal aortic aneurysm repair. To avoid reoperation, we excluded the aneurysm by endovascular means, using visceral-artery stenting, a chimney-graft technique. Low-profile balloons on a monorail system enabled the rapid exchange of coronary wires via a buddy-wire technique. This novel approach facilitated stenting and simultaneous angioplasty of multiple visceral vessels and the abdominal aorta. [ABSTRACT FROM AUTHOR]

Purpose: To show the feasibility of the Nellix device in conjunction with a chimney technique for treating juxtarenal aneurysms in two patients who were deemed unsuitable for fenestrated endovascular aneurysm repair or open surgery. Case Reports: Two men aged 83 and 81 years were referred with a juxtarenal abdominal aortic aneurysm (66 and 69 mm, respectively). Both were considered for open surgery as well as custom-made fenestrated stent-graft but deemed unsuitable for both options. They were both treated using the Nellix endoprosthesis in combination with chimney grafts to preserve the renal arteries. Technical success was achieved in both cases, with successful aneurysm exclusion and target vessel preservation (the right renal artery in the first case and both renal arteries in the second). At 6 months, duplex ultrasound and computed tomographic angiography of the first patient showed no signs of endoleak and patent renal arteries. The second patient developed a right retroperitoneal hematoma with minor extravasation near the lower pole of the right kidney for which coil embolization was necessary. The subsequent clinical sequelae led to respiratory insufficiency and ultimately death. Conclusion: The use of the Nellix endoprosthesis combined with chimney grafts is technically feasible. The addition of chimney grafts can increase the applicability of endovascular aneurysm sealing to treat short-neck and juxtarenal aneurysms. Further studies are needed to confirm these findings and establish longer term outcome. [ABSTRACT FROM AUTHOR]

Purpose: To investigate in an in vitro juxtarenal aneurysm flow model the feasibility and efficacy of using a sac-sealing endoprosthesis in a chimney graft configuration. Methods: In two experiments, a Nellix sac-sealing endoprosthesis was used as the main graft in a double-branched chimney graft configuration, using a self-expanding Viabahn stent-graft and a balloon-expandable Advanta V12 stent-graft in a pressurized silicone juxtarenal aneurysm flow model. In two consecutive experiments, the chimney graft balloons were inflated (1) at the beginning of and (2) to simulate varying renal ischemic times half-way through the injection of the sac-sealing polymer into the Nellix endobags. The balloons and were kept inflated until the endobags were filled and the polymer was cured. The aneurysm model was connected to a roller pump, pumping gelatin-water at a rate of 100 beats per minute. Before and after 24 hours of continuous flow, computed tomography (CT) scans were made using contrast injection. The CT scans were reconstructed and analyzed for gutter cross-sectional area, total gutter volume, chimney graft compression, and volume of space between the aneurysm wall and the endoprosthesis. Results: Differences in gutter size between both types of chimney grafts were minimal. Chimney graft compression exceeded 50% if the balloons were inflated in the chimney grafts halfway through polymer injection into the endobag. Twenty-four hours of flow did not influence chimney graft patency or gutter size. Conclusion: In a juxtarenal aneurysm flow model, we demonstrated the technical feasibility of a sac-sealing endoprosthesis in a chimney graft configuration. This early evidence suggests that balloon dilation of chimney grafts should occur over the entire period of polymer injection and curing to prevent considerable chimney graft compression. [ABSTRACT FROM AUTHOR]

Purpose: To report the use of parallel grafts to extend the proximal landing zone for stent-graft repair of aortic transection involving an aberrant right subclavian artery (ARSA). Case Report: A 28-year-old patient was referred for treatment of traumatic aortic transection with contained rupture at the level of an ARSA. Immediate thoracic endovascular aortic repair (TEVAR) was planned because of hemodynamic instability. To achieve rapid sealing and maintain perfusion to both subclavian arteries, a chimney stent to the left subclavian artery (LSA) and a periscope stent-graft to the ARSA were deployed successfully. After surgical repair of all fractures, the patient was discharged 1 month after the initial injury in good condition. Imaging follow-up at 10 months showed a stable repair, patent parallel grafts, and no complications. Conclusion: TEVAR with chimney and periscope grafts proved to be a safe and quick treatment for a patient requiring ARSA repair in acute aortic transection. This technique maintained blood flow to the ARSA and LSA in a totally endovascular approach, which could be very valuable in transection cases where bypass surgery to supra-aortic branches is compromised or deemed challenging due to thoracic wall and/or neck trauma. Parallel grafting can be a valuable tool to address any acute aortic pathology as it can be performed with off-the-shelf devices. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the performance of periscope and/or chimney grafts (CPGs) in the endovascular treatment of pararenal or thoracoabdominal aneurysms using off-the-shelf devices. Methods: Between February 2002 and August 2012, 77 consecutive patients (62 men; mean age 73±9 years) suffering from pararenal aortic (n=55), thoracoabdominal (n=16), or arch to visceral artery aneurysms (n=6) were treated with aortic stent-graft implantation requiring chimney and/or periscope grafts to maintain side branch perfusion. CPGs were planned in advance and were not used as bailout. A standardized follow-up protocol including computed tomographic angiography, laboratory testing, and clinical examination was performed at 6 weeks; 3, 6, and 12 months; and annually thereafter. Results: Technical success was achieved in 76 (99%) patients; 1 branch stent-graft became dislocated from a renal artery, which could not be re-accessed. Overall, 169 target vessels (121 renal arteries, 30 superior mesenteric arteries, 17 celiac trunks, and 1 inferior mesenteric artery) were addressed with the chimney graft configuration in 111 and the periscope graft configuration in 58. In total, 228 devices were used for the CPGs: 213 Viabahn stent-grafts and 15 bare metal stents. Over a mean 25±16 months (range 1-121), 9 patients died of unrelated causes. Nearly all (95%) of the patients demonstrated a decreased or stable aneurysm size on imaging; there was a mean 13% shrinkage in aneurysm diameter. Twenty patients had primary type 1/111 endoleaks at discharge; in follow-up, only 3 of these were still present (no secondary or recurrent endoleaks were noted). Additional endovascular maneuvers were required for CPG-related complications in 13 patients from intervention throughout follow-up. Overall, 4 CPGs occluded (98% target vessel patency); no stent-graft migration was observed. Renal function remained stable in all patients. Conclusion: In this series, the use of CPGs has proven to be a feasible, safe, and effective way to treat thoracoabdominal and pararenal aneurysms with maintenance of blood flow to the renovisceral arteries. Nearly all of the aneurysms showed no increase in diameter over a >2-year mean follow-up, which supports the midterm adequacy of the CPG technique as a method to effectively revascularize branch vessels with few endoleaks or branch occlusions. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the feasibility of using endoanchor technology to reduce chimney graft-related gutter size in a juxtarenal aneurysm model. Methods: In silicone juxtarenal aortic aneurysm models with two sizes of branch arteries and two sizes of aorta, single chimney graft (CG) configurations were constructed using 6-mm Atrium balloon-expandable stent-grafts in association with two sizes of Gore Excluder main grafts (23 and 28.5 mm). Configurations without Aptus EndoAnchors, with suprarenat placement of EndoAnchors, and with additional infrarenal placement of EndoAnchors were investigated. A total of 12 CG configurations were scanned using 64-slice computed tomography. Gutter volume and gutter areas at the top and bottom of the sealing zone were measured with image processing software. Results: The combination of supra- and infrarenal placement of endoanchors led to a reduction in gutter volume compared to unanchored configurations. The same configurations also led to a decrease in gutter area at the bottom of the sealing zone. Conclusion: It is feasible to reduce gutters in CG configurations with the use of endoanchors in an in vitro juxtarenal aneurysm model. [ABSTRACT FROM AUTHOR]

Purpose: To present a technique for transfemoral implantation of parallel grafts into the renal arteries in patients with anatomy or morphology that blocks standard antegrade chimney graft delivery. Technique: In a totally percutaneous approach, a 5-F pigtail angiographic catheter is passed into the aorta above the renal arteries via a 0.035-inch hydrophilic guidewire, followed by an 8-F sheath. The target vessel is cannulated with the hydrophilic wire followed by a 5-F reverse curve catheter; the wire is changed for a Rosen wire. The main stent-graft body is delivered and parked at the level of the aortic bifurcation. The Viabahn chimney endocraft is advanced ~1 to 2 cm into the target renal artery and deployed such that its proximal end faces downward; its distal end is fixed in place with an inflated angioplasty balloon. A stiff guidewire is inserted coaxially through the 8-F sheath, the Rosen guidewire is removed, and the 8-F sheath is carefully pushed over the stiff guidewire, lifting the sheath and chimney endograft upward. With the chimney reoriented cranially, the aortic stent-graft is deployed immediately. The abdominal stent-graft and the chimney graft(s) are molded synchronously using kissing balloons. Conclusion: Transfemoral placement of chimney covered stents by the lift technique in cases of unsuccessful or hazardous catheterization of the target vessels via the upper extremity is safe and feasible in centers experienced with the standard chimney technique. [ABSTRACT FROM AUTHOR]

Purpose: To report a new technique to preserve the internal iliac artery (IIA) in cases of aortoiliac aneurysms. Technique: Under bilateral common femoral artery (CFA) exposure, a crossover sheath was inserted from the contralateral CFA to the ipsilateral IIA involved in the common lilac artery (CIA) aneurysm. A Viabahn stent-graft was positioned 2 cm inside the IIA. The main body abdominal stent-graft was inserted through the ipsilateral CFA with distal sealing in the external iliac artery (EIA). The gate was cannulated, and the limb extension was positioned in the contralateral CIA near the IIA orifice. After the first Viabahn deployment, a second device was deployed with a minimum 1-cm overlap inside the first Viabahn and 2 mm distal to the limb extension. For bilateral CIA aneurysms, the Viabahn and extension limb were landed in the EIA with IIA embolization. In the past year, this technique has been used in 5 patients with success. There was no acute branch occlusion or type I endoleak from the IIA or chimney graft gutters on imaging studies up to 6 months. Conclusion: This technique is easy to use and avoids the brachial access of the sandwich technique and the additional cost of an iliac branch device. [ABSTRACT FROM AUTHOR]

Purpose: To report endovascular repair with the chimney technique of type B aortic dissection involving a right-sided aortic arch (RAA). Case Reports: Two hypertensive men aged 48 and 42 years with symptoms of aortic dissection resistant to medical therapy underwent emergent thoracic endovascular aortic repair with the chimney technique to extend the proximal landing zones. Both patients had right-sided arches with mirror image branching. One patient required a bare metal chimney stent to maintain perfusion to the right subclavian artery, while the other patient had a chimney stent to revascularize the right common carotid artery. Short-term follow-up (1 year and 1 month, respectively) showed that there was positive aortic remodeling, and the chimney stents were patent. Conclusion: Chimney TEVAR seems safe and effective for Stanford type B dissection in patients having RAA with mirror image branching and no sufficient proximal fixation zone. [ABSTRACT FROM AUTHOR]

Purpose: To report the initial use of a transseptal snare-assisted pull-down technique to facilitate stent-graft passage in the aortic arch. Case Report: A 27-year-old man with Takayasu arteritis presented with large aneurysms in the aortic arch and descending aorta. During thoracic endovascular aortic repair (TEVAR), stent-graft passage through the aortic arch was impossible due to recurrent upward prolapse of the delivery system in the arch aneurysm. The problem was resolved in two steps. First, antegrade ascending aortic access was obtained through a transseptal sheath. The sheath was stabilized by an indwelling transseptal guidewire held taut by a snare in the descending aorta. Next, simultaneously pushing inward on the stent-graft system from the groin and pulling down on the stiff delivery guidewire using another snare introduced through the transseptal sheath moved the wire/delivery system as a unit through the arch. Both aneurysms were successfully excluded; flow into the aortic arch branches was preserved using chimney grafts. Conclusion: Use of antegrade ascending aortic access through a stabilized transseptal sheath and snare-assisted pull down of the delivery system to facilitate retrograde stent-graft passage in the aortic arch made it possible to complete the TEVAR procedure in difficult arch anatomy. [ABSTRACT FROM AUTHOR]

Purpose: To determine gutter size and stent-graft geometry in an in vitro juxtarenal aneurysm model using various chimney graft (CG) configurations. Methods: Two silicone juxtarenal aortic aneurysm models were constructed combining different diameters of the aorta and renal artery. In a single-branched CG configuration, 2 sizes (23 and 28.5 mm) of Excluder stent-grafts were tested individually with 2 sizes of 2 types of CGs: Advanta balloon-expandable (BE) stent-grafts (6X59 and 12x61 mm) and Viabahn self-expanding (SE) stent-grafts (6x50 and 13x50 mm). All combinations were tested with a short (10-mm) and long (20-mm) sealing zone between the CG and main graft (total 16 configurations). Immediately after deployment, the CG configuration was scanned using a 64-slice computed tomography scanner. Gutter sizes were measured at different levels of the sealing zone. Results: At the top of the sealing zone, the gutters were significantly larger in the BE CGs compared to SE CGs in combination with the 23-mm main graft (p=0.021). At the bottom of the sealing zone, there were no statistically significant differences (p=0.77). No significant differences were seen using the 28.5-mm main graft. Median gutter size was larger in the 6-mm CGs. The length of the sealing zone had no influence on gutter size. Significant compression of the main graft was found using 12 or 13-mm CGs compared to 6-mm CGs (p=0.001). Conclusion: In this in vitro study, the CG configurations with BE stent-grafts show larger gutters than configurations with SE stent-grafts in small main grafts. Main graft compression is increased using wider CG stent-grafts. [ABSTRACT FROM AUTHOR]

Purpose: To review the literature reporting open surgical and endovascular treatment of juxtarenal aortic aneurysm (JAA). Methods: A systematic search of the PubMed database was carried out to identify English-language articles published between January 2001 and July 2012 on the management of JAA with open surgery, fenestrated endovascular aneurysm repair (F-EVAR), and the chimney graft technique (Ch-EVAR). The search found 20 studies with a total of 1725 patients (76% men; age range 66-74 years) undergoing open surgery, 10 studies detailing 931 patients (87.6% men; age range 72-75 years) receiving F-EVAR, and 5 studies comprising 94 patients (75% men; age range 68-82) reporting Ch-EVAR. Results: A total of 2465 vessels were targeted with fenestrations and 151 with chimney grafts (CG); intraoperative target vessel preservation was 98.6% and 98.0%, respectively. Cumulative 30-day mortality was 3.4%, 2.4%, and 5.3% for open surgery, F-EVAR and Ch-EVAR, respectively (p=NS). Impaired renal function was noted in 18.5%, 9.8%, and 12% following open surgery, F-EVAR, and Ch-EVAR, respectively (open vs. F-EVAR: p<0.001). New-onset dialysis was required postoperatively in 3.9%, 1.5%, and 2.1%, respectively (open vs. F-EVAR: p<0.001). Postoperative cardiac complications were noted in 11.3%, 3.7%, and 7.4%, respectively (open vs. F-EVAR: p<0.001). The incidence of ischemic stroke was 0.1% and 0.3% following open surgery and F-EVAR, but 3.2% after Ch-EVAR (open vs. Ch-EVAR: p=0.002; F-EVAR vs. Ch-EVAR: p=0.012). Early proximal type I endoleak was lower after F-EVAR compared to Ch-EVAR (4.3% vs. 10%, respectively, p=0.002). Conclusion: Open surgery remains a safe and effective treatment option for good risk patients with JAA. F-EVAR is associated with low operative mortality, compares favorably to open surgery in terms of morbidity, and current midterm data indicate that it can be a valid treatment option in both low- and high-risk patients. Early results of Ch-EVAR demonstrate feasibility only. In view of the limited number of reports and the lack of long-term data, the technique should be considered only in acute poor surgical risk patients, as a bailout in case of unintentional renal artery coverage, or in elective poor surgical cases that are not suitable for F-EVAR. [ABSTRACT FROM AUTHOR]

Purpose: To present the 24-month radiological follow-up data for patients with pararenal aortic pathologies treated with chimney and periscope grafts during endovascular repair. Methods: Between January 2008 and December 2011, 124 high-risk patients with complex pararenal aortic pathologies were treated using the chimney technique at 2 European vascular and cardiovascular centers with advanced experience of the described technique. In particular, 50 patients were treated at Site 1 and 74 at Site 2. Forty (32.2%) patients (32 men; mean age 79.2±4.9 years) completed computed tomographic angiography follow-up at 24 months postoperatively. Results: The overall technical success was 100%, and the early- and midterm procedurerelated mortality was 0%. Three (2.4%) patients had a perioperative type la endoleak that persisted; two were treated by transbrachial perigraft embolization and cuff implantation. The last patient is under radiological surveillance due to a "low-flow" type la endoleak and stable sac size. A type II endoleak was detected in 7 (5.6%) patients. During the 2-year follow-up, significant shrinkage (>5 ram; n=22) or stable aneurysm diameter (n=14) was seen in 36 (90%) of the cases. Overall, mean aneurysm sac shrinkage was 12% (p=0.002) and 10% (p=0.014) for the 2 centers, respectively (overall IO=0.008). The causes for sac progression in the 4 (10%) patients were a type la endoleak, 2 type II endoleaks, and endotension. Conclusion: The present study demonstrates that the use of chimney and/or periscope endografts for pararenal aortic pathologies achieves and maintains successful exclusion of the aneurysm in 90% of the cases at 24 months of radiological follow-up. In centers experienced with this approach, the chimney technique may represent a reliable therapeutic modality in selected patients. [ABSTRACT FROM AUTHOR]

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