Chimney Grafts Research Articles

Long-term Results of Endovascular Aneurysm Sealing in Treatment of Infrarenal Abdominal Aortic Aneurysm With Unfavourable Morphology

Introduction: Endovascular aneurysm repair (EVAR) is a less invasive alternative of treatment of patients with abdominal aortic aneurysm (AAA). Its applicability however is limited by the AAA anatomy. Endovascular aneurysm sealing originally emerged as an endovascular solution for AAA repair with very promising early results. The purpose of this study was to report long-term results of EVAS of AAAs with unfavourable anatomy for EVAR. Methods: A prospectively maintained database of 42 patients with EVAR-unfavourable anatomy treated by EVAS was analysed. The median age of the patients was 74 (IQR 67-80) years. The median diameter of AAA was 61 (IQR 56-71) mm. The EVAS consisted of implantation of two balloon expandable aorto-iliac stent-grafts surrounded by polymer filled endobags. In case of proximal AAA neck shorter than 5 mm chimney grafts were implanted. The final angiographic result, intra- and early post-operative complications were noted. A follow-up included a clinical assessment angio-CT 4-6 weeks and 12 months after the procedure and duplex Doppler at 12 months intervals thereafter. In case of any abnormalities detected in either clinical or duplex Doppler examination an angio-CT was performed. Patency of the aorto-iliac stents and chimney grafts, occurrence of graft failure and all additional interventions and/or events were noted in the database. The graft failure was defined as AAA growth of more than 5mm, type I endoleak, occlusion of the stent-graft or chimney graft or aneurysm rupture. All-cause mortality (ACM) and aneurysm related mortality (ARM) were analysed with Kaplan-Meier estimates. Results: The procedure was completed in all patients. Twenty-eight chimney grafts were implanted in 19 patients. There were two intraoperative ruptures, one of an aortic neck that required conversion to an open repair and one of an external iliac artery that was successfully treated with implantation of a self-expandible covered stent. One patient died in an early postoperative period. The median follow-up period was 24 (IQR 12-34) months. The cumulative ACM was 15, 21 and 35% at 12, 24 and 36 months respectively and the cumulative ARM was 8, 11 and 27% at 12, 24 and 36 months respectively. Three out of five aneurysm related deaths were due to a secondary aorto-duodenal fistula. The cumulative incidence of graft failure was 20, 27 and 42% at 12, 24 and 36 months, respectively. Cumulative incidence of endoleak was 5, 9 and 23% at 12, 24 and 36 months, respectively.The graft failure increased significantly both ACM (p = 0,012) and ARM (p = 0,00003). The implantation of chimney grafts at the initial procedure increased significantly ARM (p=0,008). The presence of endoleak did not have any significant influence on ACM and ARM. Conclusion: Patients treated with EVAS for AAA with EVAR-unfavourable anatomy, especially those with chimney grafts, have a high risk of graft failure and subsequent death. These patients require more rigorous monitoring than patient after standard EVAR. Disclosure: Nothing to disclose

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

Prospective Registry Study of a New Technique for Simplified FEVAR and Chimps by a Guidewire Fixator Verified Feasibility

Introduction - Endovascular treatment of complex aortic aneurysms is technically technically demanding, unpredictable, and involves significant risk related to long duration, radiation exposure and contrast use. A new technique to complete complex aortic repair that includes fenestrated, branched, chimney and snorkel grafts has been developed. The new technique is based on the concept of distal guidewire fixation provided by a new tool, a Guidewire Fixator. The aim of the new method is to provide predictable, simplified stentgraft treatment of complex aneurysms. Following CE- approval a Post Market Clinical Follow up study was performed to verify method feasibility. Methods - The study includes aortic arch repair using pre-loaded fenestrated stentgrafts and chimney techniques for complex abdominal and thoracoabdominal aneurysms. In the fenestrated case, the guidewire fixator was used to secure the distal position of the guidewire in the left subclavian artery, thereby obviating brachial access and a through-and-through guidewire. The stentgraft was then advanced and positioned over both the leading wire and the branch wire anchored by the fixator. After stentgraft deployment, the guidewire fixator was removed and a bridging covered stent was positioned in the left subclavian artery to complete the procedure. The technique used for the chimney and snorkel cases served to provide wire stability during deployment of the parallel grafts. A guidewire fixator was placed in the renal artery or the SMA. The covered stents for the visceral arteries were deployed simultaneously with the main aortic graft. Feasibility was verified through uneventful procedure completion, CT verification of branch patency within 30 days, and assessed by the surgeon evaluation of device handling, performance, and evaluation of procedure related benefits and problems through a questionnaire. Results - The left subclavian single branch case procedures were completed without brachial access. In the chimney procedures, the guidewire fixator provided distal fixation and stability during the entire deployment sequence and served to simplify precise positioning of the chimney grafts. The surgeon assessment of the device and procedure feasibility is presented. Conclusion - The different treatment methods were successfully completed by the novel guidewire fixation technique. Postoperative CT-angiography and Duplex examination verified patency of the targeted arterial branches. The surgeon assessment of the guidewire fixator technique supported significant benefits and provided valuable information on desired refinements of the technique.

A 10mm Aortic Arch Sealing Ring Distal to the Second Chimney Seem to Prevent a Gutter Endoleak in Aortic Arch Tevar

Introduction - A common problem when using the chimney graft technique for arch pathologies is the "gutter” endoleak, a type Ia endoleak resulting in pressure of the aneurysm sac. The chimney technique used for the renal arteries, though, seems to have less of these problems. The aim of the present study was to define the possible anatomical and technical parameter that might predict the occurrence of gutter endoleak or type Ia endoleak (EL Ia) in patients treated using chimney graft technique in aortic arch. Methods - We performed a review of our institutional endovascular aortic database of patients who had undergone TEVAR with chimney graft technique (ChTEVAR) as a debranching method of the supraaortic arteries between 2010 and 2017. Results - ChTEVAR was performed in 35 patients with a chimney in the left common carotid artery (LCCA) in eight patients, in the brachiocephalic trunk (BCT) in two patients and in both LCCA & BCT in 25 patients. The Gore® cTAG® Thoracic Endoprosthesis was used as a main stent-graft in all patients, Excluder® Iliac leg was used as a chimney in the BCT and Viabahn® (n=32) or Atrium Advanta V12® (n=3) as a chimney in the LCCA (off-label use). Five patients had an EL Ia and they all had a sealing ring distal to the most distal chimney of less than 10mm (P <.036). The rate of stent-graft oversizing (median 14%, IQR: 10-15% vs. 12%, 7-18% ), the diameter of the proximal (35mm, 34-37mm vs. 37mm, 33-41mm) and distal landing zones (26mm, 23-34mm vs. 30mm, 24-34mm) as well as the aortic diameter directly proximal to the pathology (36mm, 30-39mm vs. 34mm, 28-37mm) did not differ between the patients with and without EL Ia respectively (P>0.05). Furthermore, the patients with an EL Ia had a larger preoperative aortic arch curve diameter (P.033). A proximal overlap (chimney/aorta) >52.5 mm from the LCCA towards the aortic valves was also associated with an EL Ia (P.015). Conclusion - A sealing ring distal to the most distal chimney more than 10mm prevented from ELIa. In contrast to other studies, a longer overlap between the LCCA stent graft and the aorta would predict an ELIa. The relatively few patients and the single center nature require larger studies to verify the present results.

False Lumen Thrombosis and Aortic Diameter Changes in 6 Segments of Aorta Following TEVAR Procedure for Acute Complicated Type B Aortic Dissection

Introduction: Thoracic endovascular aortic repair (TEVAR) has proved its role in obliterating primary intima tear, increasing true lumen(TL)/false lumen (FL) ratio, depressurizing or enhancing thrombosis of FL and therefore preventing FL rupture for acute complicated type B aortic dissection (cTBAD). [1,2] However, persistently patent false lumen due to endoleaks surrounding aortic stent grafts (ASG), stent-induced new entry (SINE) and reentry of distal aorta is not uncommon. Enlargement of lower thoracic and upper abdominal aorta could follow. [2] Deteriorating blood flow of FL-perfused branch vessels(FPBV) is also a concern after TEVAR. [4] Methods: From Jan. 2015 to Jul. 2018, all cTBAD undergoing TEVAR procedures were retrospectively reviewed. Atypical TBAD including traumatic aortic injury and intramural hematoma was excluded. Series of follow-up computed tomography (CT) were meticulously reviewed to define classification of FL thrombosis, change of FL/TL ratio, aortic diameter change in 6 segments of aorta. The associated morbidity, including FPBV, mortality and re-intervention were also traced. Results: Total 42 patients, aged 24 to 86(mean55), 36 males and 6 females received TEVAR procedures for cTBAD in mean 20.2 hours from visit to operation room. Patients were discharged on postoperative day 2-120(mean 13). There were 9.5% 30-day mortality and 2.4% late mortality. 16.7% early complications included ischemic bowel, limb weakness, retrograde dissection, stroke and AKI etc. 26.2% late complications included chronic respiratory failure, pSINE, dSINE, renal infarction, chimney graft occlusion etc. Comparing to the pre-operative sizes, diameter of upper thoracic aorta and lower thoracic aorta showed no statistically significant change in the 3-year follow-up CT series. 100% and 56.7% patient's diameter of middle thoracic aorta increased in the 15 days(D)(p=0.03) and 3 months(M)(p=0.03) respectively after operation. 50% patient's diameter of upper abdominal aorta significantly started increasing during 15D to 3M after operation(p< 0.01). Middle abdominal aorta and lower abdominal aorta started increasing during 3M to 9M(p< 0.01) and 9M to 24M(p< 0.01) after operation. The FL/TL ratio in lower thoracic aorta was decreased and zero in 42.1% and 39.5% patients respectively. The FL/TL ratio in upper abdominal aorta was increased and zero in 36.8% and 23.7% patients respectively. Extent of false lumen thrombosis was 5.3% with retrograde type A aortic dissection, 23.7% with thrombosis above the stent graft, 73.8% with thrombosis throughout thoracic aorta and 10.5% complete thrombosis throughout native aorta. Conclusion: cTBADs have been managed by TEVAR with relatively high mortality and morbidity in our center due to questionable decision-making and loss of branch vessel revasculization. The morphology of aortic remodeling was disclosed with enlarging middle thoracic aorta initially and then enlargement of upper and middle abdominal aorta. Besides, the FL thrombosis is satisfying.[Survival and Freedom from Re-intervention in TEVAR for cTBAD]View Large Image Figure ViewerDownload Hi-res image Download (PPT) Disclosure: Nothing to disclose

Closing the gap between type A and type B aortic dissections.

Given its rarity little is known about natural history, surgical indications, and results of acute non-A non-B dissections. With this review, we aim to review the current knowledge of this subject. non-A non-B aortic dissections should be differentiated from type B aortic dissections. A strikingly high proportion of these patients have a complicate course requiring treatment and the mortality of patients treated with medical therapy is substantially higher compared to type B dissections. Surgical and endovascular treatment can be accomplished safety, with very good results in terms of mortality and morbidity also in the acute setting. Several treatments options are available including endovascular repair with thoracic endovascular aortic repair (TEVAR) associated with Chimney grafts or carotid to subclavian by pass, open arch replacement mainly by means of the frozen elephant trunk technique and hybrid arch repair with debranching of the supra-aortic vessel and zone 0 TEVAR. considering the high rate of complication, the high mortality of patients managed medically and the safety of surgical and endovascular repair, early invasive treatment of non-A non-B dissections may be further considered. The treatment should be tailored to the morphology of the dissected aorta with TEVAR reserved to more distal lesions and open arch replacement with the FET technique for more proximal lesions.

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.

Quantitative Stent Graft Motion in ECG Gated CT by Image Registration and Segmentation: In Vitro Validation and Preliminary Clinical Results

The dynamic endovascular environment of stent grafts may influence long term outcome after endovascular aneurysm repair (EVAR). The sealing and fixation of a stent graft to the aortic wall is challenged at every heartbeat, yet knowledge of the cardiac induced dynamics of stent grafts is sparse. Understanding the stent-artery interaction is crucial for device development and may aid the prediction of failure in the individual patient. The aim of this work was to establish quantitative stent graft motion in multiphasic electrocardiogram (ECG) gated computed tomography (CT) by image registration and segmentation techniques. Experimental validation was performed by evaluating a series of ECG gated CT scans of a stent graft moving at different amplitudes of displacement at different virtual heart rates using a motion generating device with synchronised ECG triggering. The methodology was further tested on clinical data of patients treated with EVAR devices with different stent graft designs. Displacement during the cardiac cycle was analysed for points on the fixating stent rings, the branches or fenestrations, and the spine. Errors for the amplitude of displacement measured invitro at individual points on the wire frame were at most 0.3mm. In situ cardiac induced displacement of the devices was found to differ per location and also depended on the type of stent graft. Displacement during the cardiac cycle was greatest in a fenestrated device and smallest in a chimney graft sac anchoring endosystem, with maximum displacement varying from 0.0 to 1.4mm. There was no substantial displacement measurable in the spine. A novel methodology to quantify and visualise stent graft motion in multiphasic ECG gated CT has been validated invitro and tested invivo. This methodology enables further exploration of in situ motion of different stent grafts and branch stents and their interaction with native vessels.

In Vitro Evaluation of Balloon-Expandable Chimney Grafts in the Renal Arteries Combined With the Endurant Endograft

Purpose: To compare balloon-expandable covered stents (BECS) available for use as renal chimney grafts to the Advanta V12 approved for use with the Endurant endograft. Materials and Methods: A silicone model was manufactured based on preoperative computed tomography angiography (CTA) scans of a patient with a 7-cm juxtarenal aneurysm treated with an Endurant bifurcated endograft and an Advanta V12 covered stent for the 6-mm-diameter right renal artery. The model was placed in a flow box filled with a 37°C blood-mimicking solution equipped with a pulsatile pumping system (140/60 mm Hg). The tested BECS were the Advanta V12, the VBX, and the BeGraft+. A 36-mm-diameter Endurant II endograft with a 16-mm-diameter contralateral limb and a 6×59-mm BECS chimney graft were used in 9 consecutive tests (3 for each combination). After each implantation, the model was placed in the CT scanner, and 2 radiologists blinded to the test device independently measured the gutter areas and the patent chimney graft lumen at the level of the Endurant’s suprarenal stent, at the level of the chimney’s maximum curvature, and 10 mm inside the renal artery. The intraclass correlation coefficients (ICC) were calculated to assess interreader reliability. Results: The mean gutter areas were 19.3±7, 20.2±8, and 22.3±8 mm2 for the Advanta, VBX, and BeGraft+, respectively (all p>0.05). At the level of the aortic endograft’s suprarenal stent struts, the mean diameter of the Advanta V12, VBX, and BeGraft+ were 4.46±0.3, 4.12±0.4, and 4.12±0.3 mm, respectively (all p>0.05). At the level of the maximum chimney graft angulation, the mean diameters were 3.77±0.3, 4.16±0.1, and 3.74±0.3 mm, respectively (all p>0.05). In the right renal artery, the mean diameters were 3.91±0.2, 4.05±0.9, and 4.3±0.4 mm, respectively (all p>0.05). The ICCs varied between 0.7 and 0.9, indicating good agreement between readers. Conclusion: These in vitro findings showed comparable results between the Advanta V12 and the available BECS used in conjunction with the Endurant endograft according to the instructions for use. Further clinical evaluation is needed to confirm these results.

A Shorter Aortic Arch Sealing Ring (< 10 mm) Distal to the Most Distal Chimney Seems to Be an Additional Important Factor Contributing to a Gutter Endoleak in Aortic Arch TEVAR

The aim of the present study was to define the possible anatomical and technical parameter that might predict the occurrence of gutter endoleak or type Ia endoleak (EL Ia) in patients treated with the chimney graft (CG) technique for the brachiocephalic trunk (BCT) and left common carotid artery (LCCA) due to aortic arch pathologies. We reviewed our institutional endovascular aortic database of patients, who between 2010 and 2018 had undergone thoracic endovascular aortic repair (TEVAR) with chimney graft technique (ChTEVAR) as a debranching method of the supraaortic arteries. ChTEVAR was performed in 45 patients of whom a chimney in both the LCCA and the BCT was used in 32 patients, only in the LCCA in twelve patients, and only in the BCT in one patient. Eight patients (17.8%) had an EL Ia (based on postoperative computed tomography angiography). No late EL Ia was detected during the follow-up period. All patients with a postoperative EL Ia received 2 CGs with one each for the BCT, and LCCA had either no or a sealing ring distal to the most distal chimney of less than 10mm versus patients with a longer sealing zone (P=0.043). Patients with an endoleak did not differ from those without endoleak with respect to stent-graft oversizing, the diameter of the proximal and distal landing zones, or the aortic diameter directly proximal to the pathology. A sealing ring distal to the most distal chimney of more than 10mm seems to be associated with a reduced risk of an EL Ia. The relatively few patients and the single-center nature require larger studies to verify the present results.

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.

Endovascular Hybrid Repair of True Ascending Aortic Aneurysms Using Double Graft Wrapping to Prepare a Landing Zone for Ascending Aortic Stent-Graft Placement: A Cohort Study

Purpose: To describe a hybrid procedure that avoids cardiopulmonary bypass to treat patients with true ascending aortic aneurysms without a suitable proximal landing zone for endovascular repair. Material and Methods: Thirteen consecutive patients (mean age 75.9±6.5 years; 8 women) with true ascending aortic aneurysms were treated with the endovascular hybrid repair of true aortic aneurysms (EHTA) approach, which consists of a conventional sternotomy with double wrapping of the ascending aorta followed by staged stent-graft placement. Via sternotomy, a polypropylene mesh trimmed to downsize the aneurysm is placed around the dilated ascending aorta and sutured to the adventitia. A similarly trimmed polytetrafluoroethylene graft is placed loosely around the first wrap to avoid adhesions and secure the proximal landing zone. There is no need for cardiopulmonary bypass. A few days later, a standard thoracic stent-graft is deployed via either a transaxillary or transfemoral access; chimney or bypass grafts are used as needed to revascularize the supra-aortic vessels. Results: The ascending aortic diameter was reduced from a mean 5.7 cm (range 4.8–6.5) to 3.9 cm (range 3.2–4.3) after wrapping. The mean interval between surgery and stent-graft placement was 5 days. In this interval, 2 patients with significant reduction in the diameter of the ascending aorta elected to forego placement of a stent-graft. Of the 11 patients who underwent the full hybrid EHTA procedure, the ascending aortic stent-graft was combined with a chimney graft in the innominate artery in 4 cases. In 1 patient, a supra-aortic debranching procedure using a bifurcated Dacron graft to the innominate and left common carotid arteries was performed after wrapping with the polypropylene mesh. There was no mortality or neurological complication. A sternal wound infection required a prolonged hospital stay. At a mean follow-up of 13.8 months (range 3–24), there has been no death, type I endoleak, or sign of aneurysm enlargement on imaging. Conclusion: This technique permits complete endovascular exclusion of an ascending aortic aneurysm in a less invasive approach than standard open repair. Although this is only a small cohort of patients without long-term follow-up, it seems that this hybrid procedure is associated with low morbidity and mortality. It offers a beating-heart approach to treat true ascending aortic aneurysms in selected high-risk patients.

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.

Preliminary outcome of Nellix-in-Nellix extensions in patients treated with failed endovascular aneurysm sealing

BackgroundThe 1-year results of the use of the Nellix (Endologix Inc, Irvine, Calif) endovascular aneurysm sealing (EVAS) device were initially promising. However, midterm complications including migration and aneurysm growth occurred more frequently than expected, which provided an incentive to refine the instructions for use. Strategies for the management of complications arising after endovascular aneurysm repair are often not applicable for EVAS, given the unique configuration of the Nellix device, and new techniques are needed. This study analyzes the clinical outcomes of both elective and emergency deployment of a new Nellix device within a primarily placed device, for failure of EVAS, which we refer to as a Nellix-in-Nellix application (NINA). MethodsThis is a global, retrospective, observational cohort study focusing on the early outcome of NINA for failed EVAS, including data from 11 European institutions and 1 hospital in New Zealand. ResultsA total of 41 patients were identified who underwent a NINA procedure. Of these, 32 (78%) were placed electively and 9 (22%) were placed on an emergency basis. Seven patients were initially treated with chimney EVAS (n = 5 in the elective NINA group and n = 2 in the emergency NINA group). The average time between the primary EVAS procedure and NINA was 573 days (interquartile range, [IQR] 397-1078 days) and 478 days (IQR, 120-806) for the elective and emergency groups, respectively. The indication for elective NINA was endoleak with migration (50%), endoleak without migration (25%), migration without endoleak (16%), and other (9%). Chimney grafts were used in 21 of 32 patients in the elective group and 3 of 9 patients in the emergency group. Technical success was achieved in 94% of patients in the elective group and 100% of patients in the emergency group. At latest follow-up (median, 104 days; IQR, 49-328 days), there were three aneurysm-related deaths (9%), no ruptures, and five device-related reinterventions (16%) within the elective group. In the emergency group (median follow-up, 23 days; IQR, 7-61 days), there were four aneurysm-related deaths and three aneurysm-related reinterventions. ConclusionsIn conclusion, a NINA can be used to treat late failures of EVAS with an acceptable technical success rate and can be used when more established treatment options are unfeasible or contraindicated. The durability of this technique needs to be further reviewed.

Handmade stent graft fenestration to preserve left subclavian artery in thoracic endovascular aortic repair†.

This study aimed to evaluate the efficacy and safety of a handmade fenestrated stent graft over an aortic stent graft for preserving the left subclavian artery (LSA) in thoracic endovascular aortic repair (TEVAR). From July 2015 to October 2018, a total of 32 consecutive patients with various thoracic aortic pathologies who underwent TEVAR in which handmade fenestration over a thoracic aortic stent graft was used for LSA were included. Outcomes including technical success, procedure-related complications, perioperative mortality and morbidity and graft patency were analysed. Twenty-four patients (75.00%) presented with aortic dissection, 5 patients (15.63%) with thoracic aortic aneurysm and 2 patients (6.25%) with penetrating aortic ulcer; 1 patient (3.13%) required re-TEVAR due to endoleak and sac expansion from previous TEVAR for thoraco-abdominal aneurysm. TEVAR was performed in a zone 2 landing with single fenestration for LSA (26 patients, 81.25%), zone 1 landing with double fenestration for both LSA and left common carotid artery (5 patients, 15.63%) or zone 1 landing with single fenestration for LSA and a chimney graft for left common carotid artery (1 patient, 3.13%). The technical success rate, defined as the successful alignment of fenestration to LSA, was 93.75%. At a mean follow-up of 17.3 months, 4 cases of endoleak and 2 cases of stent graft-induced new entry were noted, 3 of which were treated endovascularly. Our preliminary results demonstrate the viability of preserving LSA blood flow in TEVAR using a handmade stent graft fenestration to treat various aortic pathologies in various clinical situations and the technical feasibility and short-term results that may justify the use of this method in emergency cases.

Outcomes of Chimney Thoracic Endovascular Aortic Repair for an Aortic Arch Aneurysm

Chimney thoracic endovascular aneurysm repair (TEVAR) has advantages that include no requirements for special devices; however, problems have been identified such as gutter leaks. The aim of this study is to evaluate the short- and mid-term results of TEVAR with chimney technique including the safety, efficacy, and risk factors for occurrence of gutter endoleak in this technique. A retrospective single-center study was conducted on 55 consecutive patients who underwent first-time chimney TEVAR for arch aneurysms in the past 7years. This consisted of 33 cases of single-chimney (SC) TEVAR and 22 cases of double-chimney (DC) TEVAR. The outcomes of these 55 cases of SC-TEVAR and DC-TEVAR were retrospectively examined. Risk factors for endoleaks in chimney TEVAR were also examined. Operative mortalities of 3.0% and 4.5% were observed in SC-TEVAR and DC-TEVAR, respectively. Incidences of stroke were 12.1% in the SC-TEVAR and 4.5% in the DC-TEVAR, resulting in endoleaks in 16 patients (48.5%) in SC-TEVAR and 6 patients (27.3%) in DC-TEVAR. Only 1 of the 77 chimney grafts was occluded, with a patency rate of 98.7%. SC-TEVAR and small distance from the common carotid artery were the risk factors of type I endoleaks. Overall survival rates over a period of 1, 3, and 5years were 82.3%, 78.0%, and 57.7%, respectively, in the SC-TEVAR group and 95.2%, 89.3%, and 76.5%, respectively, in the DC-TEVAR group. Freedom from aneurysm-related death over 1, 3, and 5years was 82.3%, 69.0%, and 57.7%, respectively, in the SC-TEVAR group and 95.2%, 89.3%, and 89.3% in the DC-TEVAR group. Freedom from secondary intervention over 1, 3, and 5years was 80.2%, 64.7%, and 47.2%, respectively, in the SC-TEVAR group and 95.0%, 74.0%, and 74.0%, respectively, in the DC-TEVAR group. The short- and mid-term results of chimney TEVAR were worse than expectation. Especially, the results of SC-TEVAR were not acceptable because of extremely high incidence of type I endoleak and high incidence of stroke.

Outcomes of the Chimney Technique for Endovascular Repair of Aortic Dissection Involving the Arch Branches

The results of different chimney techniques in different zones of aortic arch were analyzed, so as to provide clues to decrease the complications of chimney thoracic endovascular repair (cTEVAR). Between April 2012 and April 2017, 234 patients with aortic dissection involving arch branches received cTEVAR. Among these patients, 156 (66.7%) received single chimney (SC), 48 (20.5%) received double chimneys (DCs), and 30 (12.8%) received triple chimneys (TCs). A total of 342 chimney grafts (CGs) were used. All chimney grafts were successfully implanted, and no migration or occlusion was observed during follow-up. Mortality of this cohort was 1.7% (4/234). Three (3/234, 1.3%) patients suffered from cerebral vascular events. Seventy-five (75/234, 32.1%) had intraoperative type I endoleak. Twenty-seven (27/75, 36.0%) of them were found to have automatically disappeared in the follow-up period. The false lumens of 33 (33/75, 44.0%) were found to be stable, and 15 (15/75, 20%) were found to have expanded and were successfully retreated by endoleak embolization. The proximal tear located in zone 0 had higher instant endoleak rate than zone 1, zone 2, and zone 3 (P=0.041; P=0.042; P=0.009). TC were found to have more instant endoleak than SC (P<0.001) and DC (P=0.012). But in the follow-up period, there was no significant difference. TCs and the proximal tear locating in zone 0 were found to be with higher instant endoleak rate, and it may need more rigorous follow-up. Some of the endoleak after cTEVAR could automatically disappear and some could be completely re-treated by gutter embolization procedure.

Deployment of stent graft in an excessively higher position above the renal artery induces a flow channel to the aneurysm in chimney endovascular aortic aneurysm repair: an in vitro study.

We aimed to investigate the influences of the sealing length above the renal artery (RA) on gutter formation, non-apposed regions between the aortic wall, stent graft (SG), and chimney graft and incidence of flow channel to the aneurysm in chimney endovascular aortic aneurysm repair (Ch-EVAR) using a juxtarenal abdominal aortic aneurysm model. Neck diameter and length of the silicone model were 24 and 4mm, respectively. In double Ch-EVAR configuration using Advanta V12, 12 combinations were tested three times with two sizes [28.5 (20%-oversize) and 31 (30%-oversize) mm] of Excluder SG, three sealing lengths above the RA (10, 20, and 30mm), and two deployment positions (anatomical and cross-leg). Gutter area, non-apposed region, and flow channels to the aneurysm were analyzed using micro-computed tomography. Average gutter area and non-apposed region of 30%-oversize SG were significantly smaller than those of 20%-oversize SG (p = 0.05). Furthermore, the non-apposed region of 30%-oversize SG with a 30-mm sealing length was significantly larger than that of the other sealing lengths. For 20%-oversize SGs, flow channel to the aneurysm was observed, except for the anatomical deployment with the sealing length of 10mm. For 30%-oversize SGs, flow channel was absent, except for the SG with a 30-mm sealing length in both deployment positions. These flow channels were frequently formed through a valley space, existing in the lower unibody above the two limbs. Our data indicated that the optimal sealing length should be chosen in consideration of the device design difference due to the device diameter in Ch-EVAR.

Sealing Devices in Chimney Aortic Repair (CH EVAS) Versus Chimney Aortic Repair with Conventional Devices (CH EVAR): A Systematic Review.

The aim of this study was to review the literature about the occurrence of postoperative type I endoleak (EL) and chimney graft thrombosis (CGT) after the use of sealing devices in chimney endovascular aortic repair (Ch EVAS), compared to chimney EVAR using conventional devices (Ch EVAR). A systematic review of the literature on PubMed and MEDLINE with the terms "Chimney" and "Parallel grafts" was performed. The review was set up following the PRISMA guidelines. Case series about the use of the chimney/snorkel technique during endovascular repair of juxtarenal/pararenal aneurysms (AAA) were considered. Only papers with full text available in English and reporting complete data with at least 1month of follow-up about at least 5 cases were included in the analysis. In total, 90 papers were assessed for eligibility. According to the inclusion criteria, only 25 papers could be analyzed (20 in the Ch EVAR group and 5 in the Ch EVAS group). A type I EL occurred in 9.3% after Ch EVAR (95% CI 7.1-12.2%) and in 8.3% after Ch EVAS (95% CI 3.5-18.5%), being not significantly different. CGT occurred in 10.7% of cases after Ch EVAR (95% CI 8.8-13%) and in 8.8% of cases after Ch EVAS (95% CI 3.3-21.3%), being also not significantly different. The reported rate of type I EL and CGT occurring after Ch EVAR tended to be slightly higher than those reported after Ch EVAS, even if the difference was not statistically significant.