Development of Off-the-shelf Stent Grafts for Juxtarenal Abdominal Aortic Aneurysms

Outcome Analysis Comparing Asymptomatic Juxtarenal Aortic Aneurysms Treated with Custom-Manufactured Fenestrated-Branched Devices and the "Off-The-Shelf" Zenith p-Branch Device

BACKGROUND

Numerous endovascular options have been used for the repair of juxtarenal aortic aneurysms (JRAAs) over the last 15 years. This study aims to compare the performance between the Zenith p-branch device and custom-manufactured fenestrated-branched devices (CMD) for the treatment of asymptomatic JRAA.

METHODS

A single-center retrospective analysis of prospectively collected data was performed. Patients with a diagnosis of JRAA submitted to endovascular repair between July 2012 and November 2021 were included in the study, being divided into 2 groups: CMD and Zenith p-branch. The following variables were analyzed: preoperative information: demographics, comorbidities, and maximum aneurysm diameter; procedural data: contrast volume, fluoroscopy time, radiation dose, estimated blood loss, and technical success; and postoperative data: 30-day mortality, duration of intensive care unit and hospital stay, major adverse events, secondary interventions, target vessel instability, and long-term survival.

RESULTS

From a total of 373 physician-sponsored investigational device exemption (Cook Medical devices) cases performed at our institution, 102 patients presented the diagnosis of JRAA. Of these, 14 patients were treated with the p-branch device (13.7%) and 88 (86.3%) with a CMD. Both groups presented similar demographic composition and maximum aneurysm diameter. All devices were successfully deployed, with no type I or III endoleaks observed at procedure completion. The contrast volume (P = 0.023) and radiation dose (P = 0.001) were significantly higher in the p-branch group. No significant difference was observed between the groups for the remaining intraoperative data. No paraplegia or ischemic colitis has been observed during the first 30 days after the surgical procedures. There was no 30-day mortality in either group. One major cardiac adverse event was registered in the CMD group. Early outcomes were similar in both groups. No significant difference was found between the groups with respect to the presence of type I or III endoleaks during the follow-up. From a total of 313 target vessels stented in the CMD group (mean of 3.55 per patient) and 56 in the p-branch group (mean of 4 per patient), 4.79% and 5.35% presented instability, respectively, with no difference observed between the groups (P = 0.743). Secondary interventions were required in 36.4% of the CMD cases and 50% of the p-branch group, but this was not statistically different (P = 0.382). In the p-branch cohort, 2 of 7 reinterventions (28.5%) were target vessel-related and in the CMD group, 10 of 32 secondary interventions (31.2%) were target vessel-related.

CONCLUSIONS

Comparable perioperative outcomes were obtained when appropriately selected patients were treated with either the off-the-shelf p-branch or CMD for JRAA. The long-term target vessel instability does not appear impacted by the presence of pivot fenestrations in comparison to other target vessel configurations. Given these outcomes, delay in CMD production time should be considered when treating patients with large juxtarenal aneurysms.

Emergent endovascular treatment options for thoracoabdominal aortic aneurysm

For a long time, parallel grafting, physician-modified endografts, and, more recently, in situ fenestration were the only go-to endovascular options for ruptured thoracoabdominal aortic aneurysm, offered mixed results, and depended mainly on the operator's and center's experience. As custom-made devices have become an established endovascular treatment option for elective thoracoabdominal aortic aneurysm, they are not a viable option in the emergency setting, as endograft production can take up to 4 months. The development of off-the-shelf (OTS) multibranched devices with a standardized configuration has allowed the treatment of ruptured thoracoabdominal aortic aneurysm with emergent branched endovascular procedures. The Zenith t-Branch device (Cook Medical) was the first readily available graft outside the United States to receive the CE mark (in 2012) and is currently the most studied device for those indications. A new device, the E-nside thoracoabdominal branch endoprosthesis OTS multibranched endograft (Artivion), has been made commercially available, and the GORE EXCLUDER thoracoabdominal branch endoprosthesis OTS multibranched endograft (W. L. Gore and Associates) is expected to be released in 2023. Due to the lack of guidelines on ruptured thoracoabdominal aortic aneurysm, this review summarizes the available treatment options (ie, parallel grafts, physician-modified endografts, in situ fenestrations, and OTS multibranched devices), compares the indications and contraindications, and points out the evidence gaps that should be filled in the next decade.

Five Year Results of Off the Shelf Fenestrated Endografts for Elective and Emergency Repair of Juxtarenal Abdominal Aortic Aneurysm

OBJECTIVE

Fenestrated endovascular aneurysm repair (FEVAR) is a well established treatment for complex abdominal aortic aneurysms (AAAs). FEVAR with custom made devices (CMDs) has limitations in both the emergency and elective settings due to time consuming manufacture. "Off the shelf" (OTS) fenestrated stent grafts are a potential solution. The primary goal was to evaluate the five year outcome of the COOK Zenith p-Branch OTS device at a single centre.

METHODS

Patients with juxtarenal AAA meeting the inclusion criteria for the COOK Zenith p-Branch device were enrolled in a prospective, non-randomised, non-comparative trial from July 2012 to September 2015. Demographic, anatomical, procedure related, and five year follow up data were collected, analysed, and adjudicated by a core laboratory. The primary aims were to assess intervention free survival and overall survival at five years.

RESULTS

Twenty-three patients were treated and 21 completed follow up. Mean time to p-Branch implantation after patient presentation was 28 hours (range 0-122 hours) in emergency cases and 67 days (range 20-112 days) in elective cases. Median procedure time was 283 minutes (range 161-475 minutes) and technical success was 91%. Mean follow up was 45 months (standard deviation ± 24.4 months). The most common adverse events were renal injuries. Primary target vessel patency was 96.4% and 94.0% after one and five years respectively. Mean time to first re-intervention was 469 days (range 0-1 567 days). Survival during the follow up period was 76%, with no aneurysm related deaths.

CONCLUSION

FEVAR with the COOK Zenith p-Branch device is safe and effective for juxtarenal AAA in a selected patient population, in both elective and emergency settings. Long term outcomes are acceptable although inferior to CMDs. Mid and long term outcomes emphasise the p-Branch as a possible endovascular treatment for juxtarenal aortic pathology where CMD is not an option. Further innovation to address target vessel complications is needed, as these seem more prevalent than after repair with CMDs.

Fenestrated Endovascular Aneurysm Repair versus Snorkel Endovascular Aneurysm Repair: Competing yet Complementary Strategies

Juxtarenal/pararenal aortic aneurysms and type IV thoracoabdominal aneurysms pose particular technical challenges for endovascular repair as they involve the visceral segment in addition to insufficient infrarenal neck for the use of standard endovascular aneurysm repair (EVAR) devices. To overcome these challenges, complex EVAR techniques have been developed to extend the proximal landing zone cephalad with maintaining perfusion to vital aortic branches, thereby broadening the applicability of endografting from the infrarenal to the suprarenal aorta. Complex EVAR can be divided into two broad categories: fenestrated endovascular aneurysm repair (FEVAR) and snorkel EVAR. FEVAR is a valid procedure with the standardized procedure, although it remains as a relatively complex procedure with a learning curve. Given time constraints for the custom fenestrated graft, snorkel EVAR may be an alternative for complex repairs in symptomatic or ruptured patients for whom custom-made endografts may not be immediately available. This article discusses these two most commonly used complex EVAR strategies.

Jotec E-Ventus BX Stent Graft Deployment in the FEVAR and Iliac Branch Device: Single Centre Experience

Objectives: To evaluate the outcomes of the E-ventus BX balloon-expandable stent graft system (Jotec, Hechingen, Germany) implanted as bridging stent grafts during fenestrated endovascular aortic repair (FEVAR) and the iliac branch device (IBD) of complex aneurysms.

Methods: This was a single centre retrospective analysis prospective study including all consecutive patients treated by FEVAR and the IBD performed with E-ventus BX stent grafts as bridging stents. Demographics of patients, the diameter and length of the bridging stent grafts, technical success, reinterventions, occlusions, post-operative events, and imaging (computed tomography [CT] scan and ultrasound) were prospectively collected in an electronic database. Follow-ups were performed with clinical assessment and a CT angiogram scan at four weeks after discharge followed by a duplex ultrasound every six months for two years and then a yearly duplex scan afterwards.

Results: Between June 2015 and October 2017, 40 consecutive patients (three females) were treated with custom made fenestrated endografts and the iliac branch device for complex aneurysms, using the E-Ventus BX stent graft. All 82 E-Ventus BX stent grafts were successfully delivered and deployed. There was no in-hospital mortality. The early bridging stents patency rate was 97.6% (80 out of 82). The two-target vessel post-operative occlusion was secondary to kink of the renal stents and failure for re-lining of the renal artery. Of the two patients, only one needed permanent dialysis. On the late follow-up (after 30 days), two other patients demonstrated a renal stent occlusion, with one treated successfully with re-lining of the stent and the other patient treated conservatively. Neither of them needed permanent dialysis. A follow-up was maintained for 36 patients until April 2018 with a median follow-up of 18 months. All bridging stents E-Ventus BX stent grafts remained patent (78 out of 82, 95.1%).

Conclusion: E-Ventus BX stent grafts used as bridging stents during FEVAR and the IBD are associated with favourable outcomes at the mid-term follow-up. Long-term follow-up is required to confirm these promising results.

Technical Aspects of Implanting the t-Branch Off-the-Shelf Multibranched Stent-Graft for Thoracoabdominal Aneurysms

Purpose: To describe the planning and technique for implantation of the t-Branch off-the-shelf multibranched aortic endograft. Technique: Total endovascular repair of thoracoabdominal aneurysms (TAAAs) with branched endografts is one of the most important paradigm shifts in the past decade. The t-Branch endograft, an off-the-shelf multibranched graft introduced in the European market in late 2012, allows treatment of patients with suitable anatomy in both the elective and urgent settings to avoid delays related to manufacturing time of custom-made devices. The steps required for the planning and implantation of the device are described, including some tips and tricks. Conclusion: The use of an off-the-shelf multibranched device is an appealing option in the treatment of TAAAs, especially in the acute setting. Nevertheless, results of complex aortic repairs with this specific device are associated with a learning curve and can be improved by identifying a number of intraoperative risks and paying heed to several technical details.

Anatomical Suitability of the Zenith Off-the-Shelf (p-Branch) Endograft in Juxtarenal Aortic Aneurysms Previously Treated Using the Chimney Technique

Purpose:

To examine the suitability of the Zenith off-the-shelf (p-branch) endograft in patients with juxta- or pararenal abdominal aortic aneurysms (J/PRAA) previously treated with endovascular aneurysm repair incorporating the chimney technique (chEVAR).

Methods:

Between January 2012 and December 2014, high-resolution computed tomography angiograms and clinical data from 50 patients (mean age 79 years; 45 men) with J/PRAAs treated with chEVAR were retrospectively reviewed. Primary anatomical suitability was evaluated according to the Investigational Device Exemption protocol for the Zenith p-branch endograft in a dedicated 3-dimensional vascular workstation. Secondary suitability was defined as any additional intervention needed to overcome adverse anatomical conditions at the access vessels. The Zenith p-branch endograft is available in 2 configurations (A and B), with the main difference being the distance between the superior mesenteric artery (SMA) and the renal fenestrations.

Results:

The p-branch endograft showed a primary suitability of 54% (n=27). Each configuration was suitable in 18 (36%) patients. Main anatomical limitations were the clock position of the left renal artery (LRA; n=7, 14%), the distance between the SMA and LRA (A: n=16, 32%; B: n=16, 32%), and significantly narrowed or calcified iliac arteries. If additional interventions at the access vessels were employed, a secondary suitability of 64% (n=32) could be achieved.

Conclusion:

In this specific group of patients treated with chEVAR, the Zenith p-branch system would be suitable in about half of the patients, which could be raised to two-thirds with ancillary access vessel procedures. A prospective clinical study is warranted to evaluate these results.

Snorkel endovascular abdominal aortic aneurysm repair versus fenestrated endovascular aneurysm repair: is it a competition?

The endovascular treatment of juxtarenal abdominal aortic aneurysm (AAA) can be performed by either a standard endovascular stent graft with additional snorkle grafts to aorta branches (snorkel endovascular aneurysm repair) or implantation of a fenestrated stent graft (fenestrated endovascular aneurysm repair). While many vascular surgeons consider snorkel endovascular aneurysm repair and fenestrated endovascular aneurysm repair to be competing techniques or alternate strategies, published procedural outcomes suggest more complementary roles. In this clinical review, the advantages and disadvantages of these two approaches are debated, as much can be learned from both strategies. Because the indications and circumstances for juxtarenal AAA repair vary based on patient-specific comorbidities and anatomy, it is recommended that vascular surgeons have access to, and experience with, both treatment strategies. Based on published outcomes, patient outcomes, stent-graft patency, and re-intervention rates are generally similar and acceptable compared with open AAA repair. We conclude that there is a time and a place for both snorkel endovascular aneurysm repair and fenestrated endovascular aneurysm repair for the endovascular management of juxtarenal and pararenal AAA anatomy.

Applicability of Zenith p-branch Standard Fenestrated Endograft in Our Series

BACKGROUND

In the endovascular treatment of abdominal aortic aneurysm (AAA) with short or absent infrarenal neck, the delay in the availability of fenestrated device and its high cost, have led to the manufacture of standardized models. Another option is the endografts with stents in parallel; however, regulated criteria for their use and long-term studies are lacking. The aim of this study was to assessed whether the AAA treated with fenestrated device or stents in parallel in our department, complied with the characteristics for the placement of the new endograft p-branch(®). Furthermore, the differences between the p-branch and the implanted prosthesis were analyzed.

METHODS

Single-center and descriptive study of 41 aneurysms treated consecutively from 2008 to 2015. The anatomic characteristics analyzed were: relative distances between the visceral arteries, time position, diameter in the sealing area and number of fenestrations, and its compatibility with the p-branch.

RESULTS

The anatomic compatibility rate with the p-branch options was 73.2% (30 cases). Of the 11 incompatible cases, 6 were due to misalignment of the visceral branches, 2 due to the aortic neck diameter being greater, another because the femoral access was inappropriate, and 2 more due to the fenestration configuration. Of the 30 cases in which compatibility existed, in 12 (40%) the configuration used coincided with the p-branch. In 13 cases, the number of fenestrations was higher than those actually used, with 23 fenestrations carried out and 39 hypothetical fenestrations with the new endograft. In the 5 remaining cases, a fenestration for the celiac trunk was necessary to achieve an adequate seal.

CONCLUSIONS

The p-branch could meet the needs of three-quarters of the aortic anatomies of our series, with favorable expectations on cost and waiting time. However, in most cases either a higher number of fenestrations are needed for visceral arteries or the proximal seal was shorter than would be ideal.

Update on the use of abdominal and thoracic endografts for treating aortic aneurysms

Endovascular abdominal and thoracic aneurysm repair has heralded a paradigm shift in the management of abdominal and thoracic aortic aneurysms. Randomized controlled trials have suggested superior short-term and equivalent long-term outcomes of endovascular repair compared with open surgery. Existing endografts have undergone several modifications to meet anatomic challenges and improve patient results. In the past, endovascular repair has been limited to infrarenal abdominal aortic aneurysms and isolated thoracic aortic aneurysms. The advent of fenestrated and branched endografts have made endovascular repair of thoracoabdominal and juxtarenal aneurysms possible. Continued evolution of endograft technology will maximize the benefit and minimize complications in patients with a range of aneurysmal disease.

Systematic Review of Off-the-Shelf or Physician-Modified Fenestrated and Branched Endografts

Purpose: To determine the safety and efficacy of off-the-shelf fenestrated/branched grafts (OSFGs) and physician-modified stent-grafts (PMSGs) for the treatment of complex abdominal aortic aneurysms. Methods: A systematic search of the MEDLINE database via PubMed from January 2001 through March 2015 retrieved 23 relevant articles evaluating the clinical outcomes following the management of patients with pararenal or thoracoabdominal aortic aneurysms. The 15 articles on PMSGs and 8 on OSFGs contained data on 308 patients (mean age 72.93±2.89 years; 213 men). The safety endpoint was major adverse events; the efficacy outcome measure was clinical treatment success (aneurysm exclusion without type I/III endoleak, permanent paralysis, long-term dialysis, or unresolved major complications). Extracted outcome data were pooled and compared between groups; data are given as the pooled proportions and 95% confidence interval (CI). Clinical data are presented as the weighted mean. Results: Of the 308 patients analyzed, almost one third were operated on an emergency basis. The mean aneurysm diameters were 75.9±17.3 mm (range 56–115) for the PMSGs and 68.1±13.7 mm (range 60–100) for the OSFGs. A total of 936 renal and visceral vessels were targeted. Major adverse events (safety) occurred in 24 (12.8%) PMSG patients (95% CI 8.6% to 18.7%) and in 9 (7.4%) OSFG patients (95% CI 3.7% to 14%). Clinical treatment success (efficacy) was observed in 171/187 (91.4%) PMSG patients (95% CI 86.2% to 94.9%) and in 115/121 (95%) OSFG patients (95% CI 89.1% to 98.0%). Corresponding cumulative 30-day target vessel and branch stent perfusion rates were 97.2% (95% CI 95.1% to 98.4%) and 97.6% (95% CI 95.5% to 98.8%) for the PMSG group and 99.6% (95% CI 98.3% to 99.9%) and 98.4% (95% CI 96.5% to 99.4%) for the OSFG group. Six (3.2%) deaths occurred in the PMSG group only; 2 (1.1%) were aneurysm related. Overall branch patency was recorded in 443/458 (96.7%) and in 468/478 (97.9%) of target vessels in the PMSG and OSFG groups, respectively. Conclusion: Off-the-shelf and physician-modified technology seems effective and safe, in both the elective and acute settings, for the treatment of complex aortic aneurysms. Future research within a randomized trial should investigate the true limitations of these devices.

Suitability of the Zenith p-Branch Standard Fenestrated Endovascular Graft for Treatment of Ruptured Abdominal Aortic Aneurysms

Purpose: To evaluate the anatomic suitability of the Zenith pivot branch (p-branch) fenestrated device in ruptured abdominal aortic aneurysms (rAAA). Methods: Contrast-enhanced computed tomography (CT) images of 206 patients (mean age 75±8 years; 175 men) with rAAA were evaluated in a dedicated 3-dimensional vascular workstation. All aneurysms found unsuitable for standard infrarenal repair were evaluated for Zenith p-branch suitability according to the Investigational Device Exemption protocol for both device configurations (A, pivot fenestrations at the same level; B, right renal fenestration located more cranially). Results: The suitability of the p-branch (A or B configuration) for short neck aneurysms (<15 mm; n=89) was 49%; of the 26 different combinations of exclusion criteria, a mismatch between a renal artery takeoff and the positioning of the corresponding fenestration was the most common. For juxta- and pararenal aneurysms (neck length <10 mm; n=66), suitability was 48%. Suitability assessed by target vessel positioning only (excluding all other limiting factors) was 58% for short neck aneurysms (n=52) and 55% for juxta- and pararenal aneurysms (n=36). Conclusion: Approximately half of patients with short neck rAAAs would be suitable for the Zenith p-branch fenestrated device according to the instructions for use. In almost 60%, the pivot fenestrations can accommodate the corresponding target vessels. More studies are needed to confirm these findings.

The shear stess profile of the pivotal fenestrated endograft at the level of the renal branches: A computational study for complex aortic aneurysms

PURPOSE

This study investigated the impact of the variant angulations on the values and distribution of wall shear stress on the renal branches and the mating vessels of a pivotal fenestrated design.

METHODS

An idealized endograft model of two renal branches was computationally reconstructed with variable angulations of the left renal branch. These ranged from the 1:30' to 3:30' o'clock position, corresponding from 45° to 105° with increments of 15°. A fluid-structure-interaction analysis was performed to estimate the wall shear stress.

RESULTS

The proximal part of the renal branch preserved quite constant wall shear stress. The transition zone between its distal end and the renal artery showed the highest values compared to the proximal and middle segments, ranging from 8.9 to 12.4 Pa. The lowest stress values presented at 90° whereas the highest at 45°. The post-mating arterial segment showed constantly low stress values regardless of the pivotal branch angle (6.3 to 6.6 Pa). The 45° configuration showed a distribution of the highest stress posteriorly whereas the 105°-angulation anteriorly.

CONCLUSIONS

The variant horizontal branch orientation influences the wall shear stress distribution across its length and affects its values only at its transition with the mating vessel. These findings and their potential association with adverse effects deserve further clinical validation.

Fenestrated and chimney endografts for juxtarenal aneurysms: early and midterm results

AIM

To assess the early and short-term outcome of fenestrated and chimney grafting for juxtarenal aortic aneurysms.

MATERIAL AND METHODS

A prospective vascular registry of 28 patients who had undergone elective primary endovascular repair for abdominal aortic aneurysm between December 2007 and August 2011 with infrarenal neck anatomy unacceptable for conventional endovascular repair. Fenestrated endografts were designed based on reconstructed computed tomography (CT) data by the authors. Off-the-shelf grafts and stents were used for chimney cases. Patients were followed up until 31 May 2012.

RESULTS

A total of 21 (75%) patients were treated with fenestrated endografts, while 7 (25%) received chimney grafts. The mean aneurysm diameter was 65 mm (standard deviation = 7 mm) and the median neck length 2.5 mm (range: 0-10 mm). Altogether, 63 (mean = 2.3/patient) visceral arteries were incorporated (42 renal, 21 superior mesenteric arteries). The overall primary technical success rate was 93% (one type I and one type III endoleak). The mean follow-up was 22 months (standard deviation: 14 months). The primary type III endoleak resolved spontaneously with thrombosis of the target vessel, while the patient with primary type I endoleak died of acute myocardial infarction 3 weeks after the procedure. Two late endoleaks developed: one type II endoleak without aneurysm sac growth remains under surveillance, while in another patient, multiple attempts to treat type I endoleak proved unsuccessful and the patient later died of gastrointestinal bleeding. A total of 4 (14%) patients so far required additional procedures. Two patients died within 30 days of the device implantation and another six during the follow-up. No rupture occurred. The cumulative survival for patients with fenestrated endografts was 85% at 1 year and for those treated with chimney technique 57%.

CONCLUSIONS

The treatment of juxtarenal aortic aneurysms seems to be feasible by exploiting various endovascular techniques. Even with a low volume of cases, good immediate and short-term results can be achieved, especially with fenestrated endografts.

Back-table modification of a bifurcated infrarenal stent-graft to aortomonoiliac for emergencies

PURPOSE

To describe a simple and quick technique for converting a Zenith bifurcated stent-graft to an aortouni-iliac device for emergency treatment of hemorrhage when a suitable marketed stent-graft is not readily available.

TECHNIQUE

The technique is described in an emergent case involving a 72-year-old man presenting with an aortoduodenal fistula and acute gastrointestinal bleeding. The Zenith device was prepared and flushed in the typical fashion. An extra stiff Lunderquist wire was advanced through the graft for better stability during the modification. The peel-away sheath was advanced beyond the hemostatic valve to allow partial release of the graft from the back then the grey positioner was retracted while the sheath was held firmly on the table, partially deploying the iliac limbs from the back side of the sheath. An occluding non-absorbable braided suture was placed at the short limb of the bifurcated graft close to the middle of the contralateral limb stent, through the webbing connecting both limbs below the flow divider of the bifurcated Zenith device. The graft was then resheathed using manual pinching of the graft or compression with umbilical tape. In the illustrated case, the stent-graft was intentionally deployed with the uncovered stents below the renal arteries to facilitate easier explantation later on.

CONCLUSION

Back-table modification of stent-grafts is feasible in emergencies for operators familiar with all technical aspects and potential risks of the modifications.

Editor's choice--hybrid treatment of thoracic, thoracoabdominal, and abdominal aortic aneurysms: a multicenter retrospective study

OBJECTIVES

The aim of this study was to assess the results of hybrid techniques for the treatment of thoracic, thoracoabdominal, and abdominal aortic aneurysms based on multicenter results and the various series regarding hybrid procedures reported in the literature.

METHODS

The results of 76 hybrid procedures performed in 19 French university hospital centers between November 2001 and October 2011 were collected. There were 50 men and 26 women, mean age 68.2 (35-86) years. All patients were considered at high risk (ASA≥3) for conventional surgery. Aneurysms involved the thoracic, abdominal, and thoracoabdominal aorta in five, 14, and 57 cases respectively. There were 11 emergent repairs. The revascularization of four visceral arteries was performed in 38 cases. Between one and three visceral arteries were revascularized in the other cases. Visceral artery debranching and stent graft deployment were performed in a one-stage procedure in 53 cases and in a two-stage procedure in 23 cases.

RESULTS

There were 26 (34.2%) postoperative deaths. Nine of the survivors developed paraplegia, of which one resolved completely. Bowel ischemia occurred in 13 cases (17.1%), and one patient was treated by a superior mesenteric artery bypass. Four patients required long-term hemodialysis. Postoperative computed tomography scan showed a type II endoleak in two patients.

CONCLUSIONS

Morbidity and mortality in this study were greater than previously reported. Candidates for hybrid aortic repair should be carefully selected.

Endovascular treatment of abdominal aortic aneurysms

Patients with abdominal aortic aneurysms (AAAs) are usually treated with endovascular aneurysm repair (EVAR), which has become the standard of care in many hospitals for patients with suitable anatomy. Clinical evidence indicates that EVAR is associated with superior perioperative outcomes and similar long-term survival compared with open repair. Since the randomized, controlled trials that provided this evidence were conducted, however, the stent graft technology for infrarenal AAA has been further developed. Improvements include profile downsizing, optimization of sealing and fixation, and the use of low porosity fabrics. In addition, imaging techniques have improved, enabling better preoperative planning, stent graft placement, and postoperative surveillance. Also in the past few years, fenestrated and branched stent grafts have increasingly been used to manage anatomically challenging aneurysms, and experiments with off-label use of stent grafts have been performed to treat patients deemed unfit or unsuitable for other treatment strategies. Overall, the indications for endovascular management of AAA are expanding to include increasingly complex and anatomically challenging aneurysms. Ongoing studies and optimization of imaging, in addition to technological refinement of stent grafts, will hopefully continue to broaden the utilization of EVAR.

Treatment of Hostile Proximal Necks During Endovascular Aneurysm Repair

Endovascular aneurysm repair (EVAR) is a therapy that continues to evolve rapidly as advances in technology are incorporated into new generations of devices and surgical practice. Although EVAR has emerged as a safe and effective treatment for patients with favorable anatomy, treatment of patients with unfavorable anatomy remains controversial and is still an off-label indication for endovascular treatment with some current stent-grafts. The proximal neck of the aneurysm remains the most hostile anatomic barrier to successful endovascular repair with long-term durability. Open surgery for unfavorable necks is still considered the gold standard treatment in contemporary practice, despite the increased mortality and morbidity attributed to suprarenal cross-clamping, particularly in high-risk patients. Evolving technology may overcome the obstacles preventing endovascular treatment of unfavorable proximal neck anatomy; current approaches include purely endovascular as well as hybrid approaches, and generally include strategies that either extend the length of the short neck, move the proximal neck more proximally, or keep the short neck intact. These approaches include the use of debranching techniques, banding, chimneys, fenestrated and branched devices, filling the sac with endobags, endoanchors, and other novel devices. These newer-generation devices appear to have promising short- and midterm results. However, lack of good evidence of efficacy with long-term results for these newer approaches still precludes wide dissemination of endovascular solutions for the hostile proximal neck.