The transition from custom-made to standardized multibranched thoracoabdominal aortic stent grafts

Expert-Based Narrative Review on Contemporary Use of an Off-The-Shelf Multibranched Endograft for Endovascular Treatment of Thoracoabdominal Aortic Aneurysms: Device Design, Anatomical Suitability, Technical Tips, Perioperative Care, Clinical Applications, and Real-World Experience

Advanced endovascular techniques, such as fenestrated stent grafts, are nowadays available that permit minimally invasive treatment of complex abdominal aortic aneurysms. However, thoracoabdominal aortic aneurysm patients have anatomic limitations to fenestrated stent-grafts given a large lumen, that is, the gap between the endograft and the inner aortic wall. This has led to the development of branched endovascular aneurysm repair as the ideal option for such patients. The Zenith t-Branch multibranched endograft (Cook Medical, Bloomington, IN), which has been commercially available in Europe to treat thoracoabdominal aortic aneurysm since June 2012, represents a feasible off-the-shelf alternative for treatment of such pathologies, especially in the urgent setting, for patients who cannot wait the time required for manufacturing and delivery of custom-made endografts. The device's anatomical suitability should be considered, especially for female patients with smaller iliofemoral vessels. Several tips may help deal with particularly complex scenarios (such as, for instance, in case of narrow inner aortic lumens or when treating patients with failure of prior endovascular aneurysm repair), and a broad array of techniques and devices must be available to ensure technical and clinical success. Despite promising early outcomes, concerns remain particularly regarding the risk for spinal cord ischemia and further assessment of long-term durability is needed, including the rate of target vessel instability and need for secondary interventions. As the published evidence mainly comes from retrospective registries, it is likely that reported outcomes may suffer from an intrinsic bias as most procedures reported to date have been carried out at high-volume aortic centers. Nonetheless, with the never-ceasing adoption of new and refined techniques, outcomes are expected to ameliorate.

Endovascular repair of pararenal and thoracoabdominal aortic aneurysms with inner and outer off-the-shelf multibranched endografts: A systematic review and meta-analysis

BACKGROUND

During the last years a great progress has been noted in device technology and operator experience in treating complex aortic aneurysms. Fenestrated and branched custom-made devices require detailed preoperative planning and production time that can take ≤12 weeks. During this awaiting period, aortic-related mortality is increased. To overcome this limitation, off-the-shelf standardized multibranched devices were launched in the market for the treatment of pararenal and thoracoabdominal aortic aneurysms (TAAAs). Our aim was to evaluate systematically all the published studies of off-the-shelf endografts for the treatment of pararenal and TAAAs.

METHODS

We performed a systematic review to identify all the eligible studies that reported outcomes to the off-the-shelf with inner or outer multibranched devices and then conducted a qualitative synthesis and meta-analysis of the results. The main outcomes were technical success, mortality, target visceral vessel instability, major adverse events, and reintervention rates. We estimated pooled proportions and 95% confidence intervals (CIs).

RESULTS

A total of 1605 study titles were identified by the initial search strategy, of which 13 (8 t-Branch, 3 E-nside, 1 We-Flow, and 1 TAMBE) were considered eligible for inclusion in the meta-analysis. A total of 595 patients (70% male) were identified among the eligible studies. In terms of procedures, 64.4% were elective, 19.2% (13.4% outer multibranched group [OMG]; 6.1% inner multibranched group [IMG]) were emergent, and 16.4% (15.6% OMG; 0.8% IMG) were urgent. The pooled technical success was 92.1% (95% CI, 83.8%-96.4%) and 96.9% (95% CI, 92.5%-98.8%) for the outer and inner multibranched endografts, respectively. The pooled 30-day mortality was 10.4 % (95% CI, 6.6%-16.1%,) and 4.2% (95% CI, 2.0%-8.6%) for the OMG and IMG, respectively. The pooled 30-day and late target visceral vessel instability for the OMG was 3.5% (95% CI, 2.0%-6.1%) and 6.2% (95% CI, 4.7%-8.0%) and for the IMG 10.4% (95% CI, 4.5%-22.5%) and 1.6% (95% CI, 0.7%-3.3%) respectively.

CONCLUSIONS

This pooled analysis indicated good technical success and mortality rates for both devices despite the high rate of urgent procedures. Pararenal and TAAAs can be treated safely using the included devices. However, further studies are required to draw additional conclusions for the IMG owing to the small sample size.

Unsuspected Limitations of 3D Printed Model in Planning of Complex Aortic Aneurysm Endovascular Treatment

OBJECTIVE

Static 3-dimensional (3D) printing became attractive for operative planning in cases that involve difficult anatomy. An interactive (low cost, fast) 3D print allowing deliberate surgical practice can be used to improve interventional simulation and planning.

BACKGROUND

Endovascular treatment of complex aortic aneurysms is technically challenging, especially in case of narrow aortic lumen or significant aortic angulation (hostile anatomy). The risk of complications such as graft kinking and target vessel occlusion is difficult to assess based solely on traditional software measuring methods and remain highly dependent on surgeon skills and expertise.

METHODS

A patient with juxtarenal AAA with hostile anatomy had a 3-dimensional printed model constructed preoperatively according to computed tomography images. Endovascular graft implantation in the 3D printed aorta with a standard T-Branch Cook (Cook® Medical, Bloomington, IN, USA) was performed preoperatively in the simulation laboratory enabling optimized feasibility, surgical planning and intraoperative decision making.

RESULTS

The 3D printed aortic model proved to be radio-opaque and allowed simulation of branched endovascular aortic repair (BREVAR). The assessment of intervention feasibility, as well as optimal branch position and orientation was found to be useful for surgeon confidence and the actual intervention in the patient. There was a remarkable agreement between the 3D printed model and both CT and X-ray angiographic images. Although the technical success was achieved as planned, a previously deployed renal stent caused unexpected difficulty in advancing the renal stent, which was not observed in the 3D model simulation.

CONCLUSION

The 3D printed aortic models can be useful for determining feasibility, optimizing planning and intraoperative decision making in hostile anatomy improving the outcome. Despite already offering satisfying accuracy at present, further advancements could enhance the 3D model capability to replicate minor anatomical deformities and variations in tissue density.

Systematic Review and Meta-analysis of Short-term and Mid-term Outcomes After Use of t-Branch Off-the-shelf Multibranched Endograft for Elective and Urgent Treatment of Thoracoabdominal Aortic Aneurysms

OBJECTIVE

To conduct a meta-analysis to assess the safety and efficacy of t-Branch off-the-shelf multibranched endograft for the treatment of thoracoabdominal aortic aneurysm (TAAA).

DATA SOURCES

PubMed, Embase, and Web of Science.

REVIEW METHODS

Online databases were searched from June 2012 to March 2023. The data were pooled together using a random-effects model of proportions. The outcomes overall included technical success, spinal cord ischemia, target vessel occlusion, type I or III endoleak, reintervention, early mortality (30-day), and mid-term outcomes. Subgroup meta-analyses and meta-regression were performed to explore variation among studies.

RESULTS

A total of 15 studies containing 1238 patients were included in the meta-analysis. The overall study quality assessment was found to be moderate to good. The pooled technical success was 97.0% (95% confidence interval [CI]=95.5-98.6, I2=53.01%, 1185/1238 cases, 15 studies). Overall, early mortality was 7.3% (95% CI=4.4-10.1, I2=74.48%, 124/1238 cases, 15 studies). Early spinal cord ischemia was 13.4% (95% CI=9.6-17.2, I2=67.24%, 160/1238 cases, 15 studies), and early type I or III endoleak was 6.0% (95% CI=3.4-8.5, I2=53.71%, 68/1032 cases, 9 studies). Mid-term outcomes showed target vessel occlusion was 4% (95% CI=1.4-6.5, I2=65.18%, 28/528 cases, 10 studies, 5-21.2 months), type I or III endoleak was 4.7% (95% CI=2-7.5, I2=49.74%, 38/512 cases, 10 studies, 5-21.2 months), reintervention was 11.2% (95% CI=8.1-14.3, I2=31.06%, 85/650 cases, 10 studies, 5-21.2 months), and pooled mortality was 13.9% (95% CI=7.2-20.7, I2=76.32%, 84/550 cases, 11 studies, 5-21.2 months). Meta-regression found a significant linear association between higher technical success and earlier publication year (p=0.014) and studies with anatomic inclusion criteria (p=0.037). Urgent patients (p=0.021) and later publication year (p=0.048) were significantly associated with higher early mortality.

CONCLUSION

The use of the off-the-shelf t-Branch multibranched endograft for elective or urgent endovascular TAAA repair is associated with high technical success rates and proved to be safe and effective at early and mid-term follow-up. However, the heterogeneity between the included studies is high, and prospective, randomized studies along with future larger studies with long-term follow-up are needed.

CLINICAL IMPACT

The Zenith t-Branch (Cook Medical, Bloomington, Ind) was approved as a commercially available device in Europe in June 2012. Although a decade has past, the outcomes of t-Branch have rarely been synthesized at the global level. This meta-analysis included 15 studies containing 1238 patients. The meta-analyses included technical success, major adverse events, reintervention, early mortality, and mid-term outcomes. The outcome was very meaningful and representative for the use of t-Branch. It is helpful for endovascular surgeons to make decisions on the treatment of TAAA patients.

Update of T-branch use from the US Aortic Research Consortium

Aortic endograft evolution has altered our approach to treating patients with both standard and complex aortic disease. In particular, fenestrated and branched aortic endografts have allowed for the expansion of therapy to include those patients with extensive thoracoabdominal aortic aneurysms (TAAAs). The fenestrations and branches allow for the aortic endografts to achieve a seal in the proximal and distal aspects of the aorto-iliac tree, to exclude the aneurysm, while maintaining perfusion to the renal and visceral vessels. Historically, many of the grafts used for this purpose are custom made devices designed for a specific patient based on their preoperative computed tomography imaging. One downside to this approach is the time it takes to construct these grafts. Given this, much effort has been directed towards developing "off-the-shelf" grafts which may be applicable to many patients in an immediate-need bases. The Zenith T-Branch device offers an off-the-shelf graft with four directional branches. Its utilization is not applicable to all patients, but can be applied to many patients with TAAAs. Large reported series on outcomes for these devices is limited to centers in Europe as well as within the United States Aortic Research Consortium. While early outcomes appear excellent, long-term outcomes related to aneurysm exclusion, branch patency, and freedom from reintervention are needed and will be forthcoming.

Stent-Graft Fabrics Incorporating a Specific Corona Ready to Fenestrate

In situ fenestration of endovascular stent-grafts has become a mainstream bailout technique to treat complex emergent aneurysms while maintaining native anatomical visceral and aortic arch blood supplies. Fabric tearing from creating the in situ fenestration using balloon angioplasty may extend beyond the intended diameter over time. Further tearing may result from the physiologic pulsatile motion at the branching site. A resultant endoleak at the fenestrated sites in stent-grafts could ultimately lead to re-pressurization of the aortic sac and, eventually, rupture. In an attempt to address this challenge, plain woven fabrics were designed. They hold a specific corona surrounding a square-shaped cluster with a plain weave fabric structure, a 2/2 twill, or a honeycomb. The corona was designed to stop potential further tearing of the fabric caused by the initial balloon angioplasty and stent or later post-implantation motion. The cluster within the corona was designed with relatively loose fabric structures (plain weave, 2/2 twill weave, and honeycomb) to facilitate the laser fenestration. Two commercial devices, Anaconda (Vascutek, Terumo Aortic) and Zenith TX2 (Cook), were selected as controls for comparison against this new design. All the specimens were characterized by morphology, thickness, and water permeability. The results demonstrated that all specimens with a low thickness and water permeability satisfied the requirements for a stent graft material that would be low profile and resistant to endoleaks. The in situ fenestrations were performed on all fabrics utilizing an Excimer laser followed by balloon angioplasty. The fabrics were further observed by light microscopy and scanning electron microscopy. The dimension of the fenestrated apertures was smaller than the balloon's diameter. The tearing was effectively confined within the corona. The clinical acceptability of this concept deserves additional bench testing and animal experimentation.

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.

Comparative Effectiveness of Treatment Modalities for Complex Aortic Aneurysms: A Network Meta-Analysis of Observational Studies

BACKGROUND

To conduct a network meta-analysis comparing multiple treatments for complex aortic aneurysms (CAAs).

METHODS

Medical databases were searched on November 11, 2022. Twenty-five studies (5,149 patients) and four treatments (open surgery [OS], chimney/snorkel endovascular aneurysm repair [CEVAR], fenestrated endovascular aneurysm repair [FEVAR], and branched endovascular aneurysm repair) were selected. Outcomes were branch vessel patency, mortality, and reintervention at short- and long-term followup, and perioperative complications.

RESULTS

Regarding branch vessel patency, OS was the most effective treatment and had higher 24-month branch vessel patency rates than CEVAR (odds ratio [OR], 10.77; 95% confidence interval [CI], 2.08-55.79). FEVAR (OR, 0.52; 95% CI, 0.27-1.00) and OS (OR, 0.39; 95% CI, 0.17-0.93) were better than CEVAR regarding 30-day mortality and 24-month mortality, respectively. Regarding 24-month reintervention, OS was better than CEVAR (OR, 3.07; 95% CI, 1.15-8.18) and FEVAR (OR, 2.48; 95% CI, 1.08-5.73). Regarding perioperative complications, FEVAR had lower acute renal failure rates than OS (OR, 0.42; 95% CI, 0.27-0.66) and CEVAR (OR, 0.47; 95% CI, 0.25-0.92) and lower myocardial infarction rates than OS (OR, 0.49; 95% CI, 0.25-0.97) and was the most effective treatment in preventing acute renal failure, myocardial infarction, bowel ischemia, and stroke, while OS was the most effective treatment in preventing spinal cord ischemia.

CONCLUSIONS

OS might have advantages regarding branch vessel patency, 24-month mortality, and reintervention and is similar to FEVAR regarding 30-day mortality. Regarding perioperative complications, FEVAR might confer advantages in preventing acute renal failure, myocardial infarction, bowel ischemia, and stroke, and OS in preventing spinal cord ischemia.

Systematic Review and Meta-Analysis of Published Studies on Endovascular Repair of Abdominal Aortic Aneurysm With the p-Branch

Background

Endovascular treatment of juxtarenal or pararenal abdominal aortic aneurysms is more popular than open surgery, mainly because it reduces perioperative mortality and morbidity. The custom-made fenestrated devices need to be tailored to each patient, so these devices require extra manufacturing and shipping time. The increased wait time may increase the risk of aneurysm rupture in some patients. In some situations, “Off-the-shelf” (OTS) fenestrated grafts can be used. The Cook Zenith p-Branch device (William Cook Australia, Brisbane, Australia) is a relatively common OTS. This study aimed to systematically evaluate all published experiences with p-Branch.

Methods

We searched PubMed, Embase, and Cochrane to find works of literature that reported on the outcomes of patients treated with the p-Branch stent-grafts. Then we conducted an assessment of quality and meta-analysis of the results. The primary endpoints were the application rate of p-Branch stent-graft (type A, B), technical success rate, and early re-intervention rate. We estimated pooled proportions and 95% CIs.

Results

Initial search of the literature included 111 articles, of which 7 studies were included in the end. A total of 260 patients were enrolled in these studies, and 218 patients were eventually treated with p-Branch. The pooled application rate of type A devices was 48% (95% CI, 29–67%), and pooled application rate of type B devices was 30% (95% CI, 16–44%). The pooled technical success rate was 87% (95% CI, 75–98%). The early re-intervention rate was 10% (95% CI, 3–17%). Midterm renal infarct rate (after 30 days) was 3% (95% CI, 0–6%). Midterm re-intervention rate (after 30 days) was 30% (95% CI, 3–57%). Midterm renal failure rate (after 30 days) was 6% (95% CI, 2–10%).

Conclusions

This pooled analysis indicated an acceptable technical success rate after p-Branch stent-graft implantation, with early and midterm re-intervention rate and renal failure rate that cannot be ignored. The p-Branch repair of juxtarenal abdominal aortic aneurysms may be an appropriate and safe option, especially in emergency situations.

Reversed and Antegrade Iliac Side Branch Stentgraft as an Alternative or Rescue Maneuver in Complex (Thoraco)Abdominal Endovascular Aortic Repair to Preserve Renal Perfusion

Purpose

To describe a technique that can preserve renal perfusion in failed bridging stent implantation of renal arteries or as intentional procedure in emergency cases, when the (thoraco)abdominal aneurysm anatomy does not meet the criteria for instructions for use of an “off-the-shelf” graft. The technique is based on reversed or antegrade integration of a standard iliac side branch graft into the aortic stentgraft system, which allows cannulation of (accessory) renal vessels.

Technique

A standard iliac side branch prosthesis is deployed and re-sheathed in reversed direction on the back table. The endograft is then implanted in the unibody in analogy to an iliac limb. The iliac side branch is cannulated followed by target vessel cannulation and covered bridging stents are deployed for completion. Furthermore, an iliac side branch prothesis can also be used to preserve relevant accessory renal arteries, when implanted in delivered antegrade loading position.

Conclusion

The use of a reversed and antegrade iliac side branch technique to revascularize renal vessels is feasible and safe in selected patients. This technique may also allow to extend the range of an “offthe- shelf” (multibranch) stentgraft, when immediate treatment is required.

Endovascular repair for thoracoabdominal aortic aneurysms: current status and future challenges

Open surgical repair has been the gold standard for treatment of thoracoabdominal aortic aneurysms (TAAA). Currently, open surgical repair has been reserved mostly for young and fit patients with connective tissue disorders, using separate branch vessel reconstructions instead of 'island' patches, and distal perfusion instead of a 'clamp and go' technique. Endovascular repair has gained widespread acceptance because of its potential to significantly decrease morbidity and mortality. Several large aortic centers have developed dedicated clinical programs to advance techniques of fenestrated-branched endovascular aortic repair (FB-EVAR) using patient-specific and off-the-shelf devices, which offers a less-invasive alternative to open repair. Although FB-EVAR was initially considered an option for older and frail patients, many centers have expanded its indications to any patient with suitable anatomy and no evidence of connective tissue disorders, independent of their clinical risk. In this article, we review current techniques and outcomes of endovascular TAAA repair.

Capturing patient anatomy for designing and manufacturing personalized prostheses

Prostheses play a critical role in healthcare provision for many patients and encompass aesthetic facial prostheses, prosthetic limbs and prosthetic joints, bones, and other implantable medical devices in musculoskeletal surgery. An increasingly important component in cutting-edge healthcare treatments is the ability to accurately capture patient anatomy in order to guide the manufacture of personalized prostheses. This article examines methods for capturing patient anatomy and discusses the degrees of personalization in medical manufacturing alongside a summary of current trends in scanning technology with a focus on identifying workflows for incorporating personalization into patient-specific products. Over the next decade, with increased harmonization of both personalization and automated prosthetic manufacturing will be the realization of improved patient compliance, satisfaction, and clinical outcomes.

Insights on Bridging Stent Grafts in Fenestrated and Branched Aortic Endografting

Major branches of the aortic arch and visceral aorta pose a particular challenge for endovascular repair of aneurysms involving these regions. To preserve perfusion through these essential branches, fenestrated and branched endografts have been used. Current fenestrated and branched aortic endografts have evolved into modular devices in which the aortic main body provides appropriate access to the target branch vessel either through reinforced fenestrations or directional cuffs as the hinge point for bridging stent grafts (BSGs). BSGs are used to connect the aortic main body and target branch vessel, and must provide both unhindered flow and a seal. Appropriate selection of BSG for target vessels in branched and fenestrated endovascular aortic repair is critical for technical success and durability. At present, there are no dedicated devices for use as BSGs, and a variety of stent grafts are currently used off-label. In this report, we review the available published series on the performance of presently available BSGs in relation to their design and selection.

Hemodynamic Parameters Predict In-stent Thrombosis After Multibranched Endovascular Repair of Complex Abdominal Aortic Aneurysms: A Retrospective Study of Branched Stent-Graft Thrombosis

Background: Branch vessel occlusion is reported in endovascular repair of aortic pathology. This study aimed to evaluate the hemodynamic indicators associated with in-stent thrombosis (IST) of a branched stent-graft (BSG) after endovascular aortic repair (EVAR) of a complex abdominal aortic aneurysm.

Methods: A retrospective evaluation was performed based on the computed tomography (CT) scans and clinical data of three patients who underwent multi-branched endovascular repair. Patient-specific 3-dimensional models were reconstructed, and hemodynamic analysis was performed for IST. Hemodynamics-related parameters including time-averaged wall shear stress (TAWSS), oscillatory shear stress index (OSI), and relative residence time (RRT) were compared among the individual patients.

Results: The flow velocity, TAWSS, OSI, and RRT were radically changed in the area of the IST. In BSGs, IST tended to occur in the regions of hemodynamic alteration near the bends in the device, where a decreased flow velocity (<0.6 m/s) and TAWSS (<0.8 Pa) and an elevated OSI (>0.2) and RRT (>5 s) were consistently observed.

Conclusions: Hemodynamic perturbations in BSGs cause a predisposition to IST, which can be predicted by a series of changes in the flow parameters. Early hemodynamic analysis might be useful for identifying and remediating IST after multibranched endovascular repair.

Branched Endograft Partial Deployment to Save Space for Vessel Cannulation When Treating Aneurysms with Narrow Aortic Lumen

PURPOSE

To describe a novel technique developed for the treatment of patients with thoracoabdominal aortic aneurysms having narrow aortic lumens using branched endografts.

TECHNIQUE

When treating patients with a narrow aortic inner diameter with branched endografts, we propose a partial graft deployment leaving the distal portion of the device inside the delivery system with the aim of spare space and facilitate target vessel cannulation.

CONCLUSIONS

Partial endograft deployment could be considered in the case of expected difficulty associated with encumbrance deriving from the distal straight graft portion. This technique could be useful to avoid target vessel loss and therein save procedural and fluoroscopy time.

Open vs. endovascular thoracoabdominal aortic aneurysm repair: tale of the tape

Open surgical repair persists as the gold-standard operation for thoracoabdominal aortic aneurysm; however, endovascular repair has become commonplace. Technical considerations in thoracoabdominal aortic aneurysm treatment are particularly complex, insofar as it involves critical branching arteries feeding the visceral organs. Newer, low-profile devices make total endovascular thoracoabdominal aortic aneurysm repair more feasible and, thus, appealing. For younger and low-risk patients, the choice between open and endovascular therapy remains controversial. Despite the advantages of a minimally invasive procedure, data suggest that endovascular aortic repair incurs a greater risk of spinal cord deficit, and the durability of endovascular aortic repair remains unclear. It is difficult to compare outcomes between endovascular and open thoracoabdominal aortic aneurysm repair, primarily because of the current investigational status of endovascular devices, the variety of approaches to endovascular repair, differing patient populations, lack of prospective randomized studies, and minimal medium- and long-tern follow-up data on endovascular repair. When deciding between open and endovascular approaches, one should consider which is more suitable for each patient. Older patients generally benefit from a less invasive approach. Open repair should be considered for young patients and those with heritable thoracic aortic disease. Infection and fistulae are best treated by open repair, although endovascular intervention as a lifesaving bridge to definitive repair has evolved to become a critical component of initial treatment. It is crucial to have technical expertise in both open and endovascular procedures to provide the best aortic repair for the patient. This may require dedicated aortic programs at tertiary institutions.

Performance of Viabahn balloon-expandable stent compared with self-expandable covered stents for branched endovascular aortic repair

OBJECTIVE

The objective of this study was to compare the performance between the Viabahn balloon-expandable stent (VBX; Viabahn [W. L. Gore & Associates, Flagstaff, Ariz]) and a covered self-expandable stent (SES; Fluency [Bard Peripheral Vascular, Tempe, Ariz]) used as bridging stents for directional branches during fenestrated or branched endovascular aneurysm repair of complex aortic aneurysms.

METHODS

Patients with thoracoabdominal aortic aneurysms (type I-IV) or pararenal aortic aneurysms either at high risk for open repair or unsuitable for endovascular repair with commercially available devices were prospectively enrolled in a physician-sponsored investigational device exemption trial. Descriptive statistics of the cohort included demographics, risk factors, and anatomic and device characteristics. Individual branches were grouped as either VBX or SES and had data analyzed for primary patency, branch-related type I or type III endoleaks, branch instability, branch-related secondary intervention, and branch-related aortic rupture or death. Categorical variables were expressed as total and percentage, and continuous variables were expressed as median (interquartile range). Kaplan-Meier curves were used to estimate long-term results. Groups were compared with the log-rank test. P value <.05 was considered statistically significant.

RESULTS

During the period from July 2012 through June 2019, there were 263 patients treated for complex aortic aneurysm (thoracoabdominal aortic aneurysm) with fenestrated or branched endografts. The devices used were either custom-manufactured devices or off-the-shelf p-Branch or t-Branch (Cook Medical, Bloomington, Ind) devices. The median age was 71 years (interquartile range, 66-79 years); 70% were male, and 81% were white. The most common cardiac risk factors were smoking (92%), hypertension (91%), hyperlipidemia (78%), and chronic obstructive pulmonary disease (52%). The total number of vessels incorporated into the repair was 977, with branches representing 18.4% (179 branches). Among these 179 branches, the celiac artery, superior mesenteric artery, right renal artery, and left renal artery received 54 (30%), 56 (31%), 38 (21%), and 31 (18%) branches, respectively. VBX and SES groups represented 96 (54%) and 81 (46%) of the branches implanted. The celiac artery, superior mesenteric artery, right renal artery, and left renal artery received VBX as a bridging stent in 40%, 46.7%, 33.8%, and 32.2% respectively. The overall cohort survival rate was 78.5% at 24 months. There was no branch-related rupture or mortality. Primary patency at 24 months (VBX, 98.1%; SES, 98.6%; log-rank, P = .95), freedom from endoleak (VBX, 95.6%; SES, 98.6%; log-rank, P = .66), freedom from secondary intervention (VBX, 94.7%; SES, 98.1%; log-rank, P = .33), and freedom from branch instability (VBX, 95.6%; SES, 97.2%; log-rank, P = .77) were similar between groups.

CONCLUSIONS

This initial experience with VBX stents demonstrated excellent primary patency and similarly low rates of branch-related complications and endoleaks, with no branch-related aortic rupture or death. Our results demonstrate that in a high-volume, experienced aortic center, the VBX stent is a safe and effective bridging stent option during branched endovascular aortic repair. Multicenter studies with a larger cohort and longer follow-up are necessary to validate these findings.

Midterm Results of Endovascular Treatment for the Patients with Thoracoabdominal Aortic Aneurysms

Treatment of thoracoabdominal aortic aneurysm (TAAA) remains a challenging pathology. Technologies and innovations of endovascular treatment, in particular the evolution of fenestrated and branched stent graft for complex aortic pathologies such as TAAA have provided excellent short-term results. However, the mid-term and long-term results of endovascular treatment for TAAA including endoleaks and branch patency are still unclear. This article provides an overview of available devices and results of endovascular treatment for TAAAs. (This is a translation of Jpn J Vasc Surg 2019; 28: 67–74.)

Long-term durability of multibranched endovascular repair of thoracoabdominal and pararenal aortic aneurysms

OBJECTIVE

The objective of this study was to assess the durability of multibranched endovascular repair of thoracoabdominal aortic aneurysms (TAAAs) and pararenal aortic aneurysms by examining the rates of late-occurring (beyond 30 days) complications.

METHODS

There were 146 patients who underwent endovascular TAAA repair using a stent graft, with a total of 538 caudally oriented self-expanding branches. Four patients died in the perioperative period and were excluded, leaving 142 patients (mean age, 73 ± 8 years; 35 [24.7%] women). Follow-up included clinical examination and computed tomography angiography at 1 month, 6 months, and 12 months and yearly thereafter.

RESULTS

Mean aneurysm diameter was 67 ± 9 mm. Sixty-seven TAAAs (47.2%) were Crawford type I, II, III, or V; 75 (52.8%) were type IV or pararenal. Three patients (2.1%) died >30 days after operation from perioperative complications. During a mean follow-up of 36 months (±28 months), there were four additional aneurysm-related deaths: one (0.7%) as a result of aneurysm rupture in the presence of untreatable type I endoleak, one (0.7%) after conversion to open repair for stent graft infection, one (0.7%) after occlusion of superior mesenteric artery and celiac branches, and one (0.7%) due to bilateral renal branch occlusion. There was one additional open conversion for stent graft infection (0.7%). Nineteen patients (13.3%) underwent 20 reinterventions for late-occurring complications, including 11 (7.7%) for renal branch occlusion or stenosis, 1 (0.7%) for mesenteric branch stenosis, 4 (2.8%) for graft limb occlusion, 1 (0.7%) for type IB endoleak (distal stent graft migration), and 1 (0.7%) for type III endoleak (fabric erosion); 2 (1.4%) open conversions were performed for stent graft infection. There were no late type IA endoleaks. By Kaplan-Meier analysis, freedom from aneurysm-related death was 91.1% and freedom from aneurysm-related death or reintervention was 76.8% at 5 years. The 5-year overall survival rate of 49.1% reflects the high rate of cardiopulmonary comorbidity. Although renal branch occlusion (23 occlusions of 256 renal branches [8.9%]) was the most common late complication, only five patients required permanent dialysis.

CONCLUSIONS

Total endovascular repair of TAAAs and pararenal aortic aneurysms using axially oriented cuffs is safe, effective, and durable in the long term.

Should endovascular approach be considered as the first option for thoraco-abdominal aortic aneurysms?

Open surgical repair has been the gold standard for treatment of thoracoabdominal aortic aneurysms (TAAAs). The technique of open TAAA repair has evolved from the use of "island" patch incorporation to separate branch vessel bypass, from "clamp and go" to routine use of distal perfusion, and towards more extensive repair in patients with connective tissue disorders. Open TAAA repair can be done with excellent results in highly specialized centers. However, these operations continue to carry excessive risk when performed outside large aortic centers, with 30-day mortality estimated on 20% according to statewide and national databases. In octogenarians, the mortality of elective open TAAA repair can be up to 40%. Endovascular repair was introduced as an alternative to open surgical repair in the elderly or higher risk patients using hybrid reconstruction, parallel grafts or fenestrated and branched endografts. Several large aortic centers have developed dedicated clinical programs to advance techniques of fenestrated-branched endovascular repair using patient-specific and off-the-shelf devices, offering a minimally invasive alternative to open repair allowing treatment of increasingly older and sicker TAAA patients. During the last decade, improvements in device design, patient selection, spinal cord injury protocols, and perioperative management have contributed to a continued decline in morbidity and mortality of fenestrated-branched endovascular aortic repair, challenging open surgical repair as the new "gold standard" for treatment of TAAAs. Despite the improved results, endovascular repair is a highly technical procedure that requires vast experience, involves a significant risk of complications, and also, has an impact on patients' physical quality of life. In this article, we review the current technical aspects of endovascular TAAA repair with the main focus on the evidence of open versus endovascular outcomes of TAAA repair.

Outcomes and complications after fenestrated-branched endovascular aortic repair

OBJECTIVE

To report the outcomes of patients enrolled in a physician-sponsored investigational device exemption trial for endovascular treatment of complex thoracoabdominal aortic aneurysms with fenestrated and/or branched devices.

METHODS

This study represents a retrospective analysis of a prospectively maintained database of patients enrolled in a physician-sponsored investigational device exemption trial for endovascular treatment of complex thoracoabdominal aneurysms between July 2012 and July 2017. Subjects included high-risk patients for open repair and patients with unsuitable anatomy for either standard endovascular aneurysm repair or Zenith (Cook Medical, Bloomington, Ind) fenestrated device. Aneurysm classification was based upon Crawford classification. We included the pararenal and paravisceral aneurysms in the type IV aneurysm group, because the repair of these aneurysms usually involved treatment of all four visceral branches. The endografts implanted were custom manufactured devices or off-the-shelf devices based on the Cook Zenith platform. Variables analyzed included preoperative demographics and comorbidities, anatomic aneurysmal characteristics, procedural details, and perioperative complications.

RESULTS

One -hundred fifty patients with a mean age of 71 ± 7.9 years were treated; 69% were male. Tobacco use (93%) and hypertension (91%) were the most common risk factors. Fifty-seven patients (38%) had a history of previous aortic repair. The mean aneurysm diameter was 62 ± 12 mm and 14 (9%) aneurysms were associated with chronic dissection. A total of 573 visceral vessels were incorporated (celiac artery/superior mesenteric artery [287 vessels], renal arteries [275 vessels], and 11 additional vessels) and 539 were stented. The celiac artery/superior mesenteric artery received a fenestrated design in 76.1% of cases. Branch designs were used in the renal artery in 13.2%, with the remainder treated with fenestrations. Spinal cord drainage was used in 51% of patients (76/150). The mean operative time, fluoroscopy time, and estimated blood loss were 283 ± 89 minutes, 83 ± 38 minutes, and 417 ± 404 mL, respectively. There were five patients (3.3%) with intraoperative complications, resulting in one intraoperative death. The early mortality was 2.7% (4/150). Major complications included respiratory failure in 7% (10/150), stroke and myocardial infarction in 0.7% each (1/150), and paraplegia in 2.7% (4/150). Acute kidney injury occurred in 4.7% of patients (7/150), two of whom required temporary dialysis. Thirty-nine percent of patients experienced at least one complication. Early branch vessel patency was 99.8% (525/526). Survival, primary, and primary-assisted branch patency at 2 years of follow-up were 79%, 97%, and 99%, respectively.

CONCLUSIONS

Endovascular repair of complex aneurysms is safe and effective when performed in a high-volume center experienced in aortic disease management. Branch vessels patency and the low incidence of paraplegia and mortality support expanded use to treat most complex thoracoabdominal aortic aneurysms.

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.

Three-Dimensional Modeling Analysis of Visceral Arteries and Kidneys during Respiration

BACKGROUND

Visceral arteries are commonly involved in endovascular repair of complex abdominal aortic aneurysms (AAAs). To improve repair techniques and reduce long-term complications involving visceral arteries, it is crucial to understand in vivo arterial geometry and the deformations due to visceral organ movement with respiration. This study quantifies deformation of the celiac, superior mesenteric (SMA), and renal arteries during respiration and correlates the deformations with diaphragmatic excursion.

METHODS

Sixteen patients with small AAAs underwent magnetic resonance angiography during inspiratory and expiratory breathholds. From geometric models of the aorta and visceral arteries, vessel length, branch angle, curvature, and positions were computed, along with degree of diaphragmatic excursion as indicated by kidney translation.

RESULTS

From inspiration to expiration, the celiac artery exhibited axial shortening of 4.8 ± 6.4% (P < 0.001) and a mean curvature increase of 0.03 ± 0.02 mm(-1), greater than other visceral arteries (P < 0.01). With expiration, the SMA, left and right renal arteries (LRA and RRA) angled upward by -9.8 ± 6.4°, -6.4 ± 6.4°, and -5.2 ± 5.0°, respectively (P < 0.005). All vessels translated superiorly (P < 0.0005) and posteriorly (P < 0.01), and the SMA translated rightward additionally (P < 0.005). The left and right kidneys translated by 22 ± 9 mm and 21 ± 9 mm, mostly superiorly (P < 0.001). Translations of all visceral arteries were moderately correlated to the right kidney (R > 0.50). Correlation of the LRA with the left kidney was greater than that of the RRA with the right kidney.

CONCLUSIONS

The celiac artery exhibited less branch angle change, and greater axial and curvature deformations than the other visceral arteries, due to the vicinity to the liver and influence of the median arcuate ligament. Correlation between visceral arteries and kidney translations revealed that diaphragmatic excursion affects vessel mobility. Weaker correlation of the RRA to the right kidney indicates mechanical shielding from the inferior vena cava.

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.

Visceral branch occlusion following aneurysm repair using multibranched thoracoabdominal stent-grafts

PURPOSE

To identify risk factors for late-occurring branch occlusion following multibranched endovascular repair of thoracoabdominal and pararenal aortic aneurysm.

METHOD

Out of 120 patients who underwent multibranched endovascular aneurysm repair between September 2005 and May 2013, 100 (78 men; mean age 72.4 ± 7.4 years) met the criteria for inclusion in the current retrospective analysis. Demographic data were gleaned from a prospectively maintained database. Mean aneurysm diameter was 66.7 ± 11.7 mm. Multiplanar reconstructions of postoperative computed tomographic angiography were used to measure 6 parameters of renal branch morphology.

RESULTS

All 100 patients had undergone successful placement of multibranched aortic stent-grafts with a total of 95 celiac branches, 100 superior mesenteric artery (SMA) branches, and 187 renal branches. During a mean follow-up of 25.6 months, there were no stent fractures or stent separations, no SMA occlusions, and only 2 (2.1%) celiac artery occlusions, neither of which required reintervention. In contrast, there were 18 (9.6%) renal branch occlusions in 16 patients, all men (p=0.02). Patients with renal branch occlusions were significantly more likely to have a history of myocardial infarction (p=0.004). The mean renal artery length was significantly greater in the occlusion group compared to the non-occlusion group (47.5 ± 13.6 vs. 39.4 ± 14.2, p=0.03). No other aspect of branch morphology was significantly different between the occlusion and non-occlusion groups.

CONCLUSION

Renal branch occlusion was by far the commonest late failure mode after multibranched endovascular aneurysm repair. The current study provides no basis for a change in patient selection or stent-graft design, only a change in the components used to construct renal branches. It is too early to tell the effect this will have.

Thoracoabdominal aortic aneurysm repair: current endovascular perspectives

Thoracoabdominal aneurysms account for roughly 3% of identified aneurysms annually in the United States. Advancements in endovascular techniques and devices have broadened their application to these complex surgical problems. This paper will focus on the current state of endovascular thoracoabdominal aneurysm repair, including specific considerations in patient selection, operative planning, and perioperative complications. Both total endovascular and hybrid options will be considered.

"Off-the-shelf" devices for complex aortic aneurysm repair

BACKGROUND

Fenestrated devices currently require a 3- to 4-week manufacturing period before implantation; as such, there have been efforts to develop "off-the-shelf" (OTS) devices to reduce the time before definitive treatment can be accomplished. We examined all patients treated for complex aortic problems at our institution during the past 12 months to evaluate the suitability and early outcomes of the OTS devices vs commercially available endovascular options.

METHODS

Between July 2012 and September 2013, patients undergoing aortic aneurysm repair were extracted from a prospectively managed aortic database. Two OTS devices, the Cook (Bloomington, Ind) p-Branch and the Endologix (Irvine, Calif) Ventana device, were being evaluated through clinical trials during this time frame. The custom Cook Zenith fenestrated endovascular (ZFEN) device was also available and approved by the U.S. Food and Drug Administration (FDA) during the study period.

RESULTS

Of 224 aortic aneurysms treated at our institution during this period, there were a total of 85 patients with type IV thoracoabdominal aneurysms including juxtarenal aneurysms. Only 23 patients (27%) met anatomic criteria for OTS devices, with 16 patients having these investigational devices implanted. The major exclusion criterion for the p-Branch device was renal axial or circumferential position; the limiting factor for Ventana was infrasuperior mesenteric artery neck length restriction. Five of the patients who would have fit criteria for an OTS device had an FDA-approved (ZFEN) device implanted instead, and two patients opted for open repair as a result of follow-up requirements. An additional 25 patients received custom-designed (ZFEN) devices (n = 30; 35%), whereas 37 (44%) others did not meet criteria for any available endovascular device and were repaired with alternative management strategies. The mean age and maximal aortic diameter of the two cohorts (OTS and ZFEN) were 71.8 years and 72.7 years (P = NS) and 61.3 mm and 58.5 mm (P = NS), respectively. Technical success was 100%, with an overall 30-day mortality of 2.1% (n = 1, ZFEN). Major complications occurred in eight patients (17%; two OTS, six ZFEN).

CONCLUSIONS

Whereas OTS device strategies will reduce the waiting times for patients with complex aortic aneurysmal disease, a significant number will still require custom-made device repair until additional device designs become available. Early experience with OTS devices does not demonstrate any significant renal risks; however, the treatment numbers are low and should be interpreted with caution until larger confirmatory studies are published. Further studies comparing the outcomes of these techniques are required to establish the best approach to handle endovascular repair of complex aortic aneurysm.

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.

Renal autotransplant for subsequent endovascular exclusion of the thoracoabdominal aorta

In the last 20 years, endovascular procedures have radically altered the treatment of diseases of the aorta. The objective of endovascular treatment of dissections is to close the entry point to redirect blood flow toward the true lumen, thereby achieving thrombosis of the false lumen. In extensive chronic dissections that have evolved with the formation of a large aneurysm, the dissection is maintained from the end of the endoprosthesis due to multiple orifices, or reentries, that communicate with the lumens. In addition, one of the primary limitations of this technique is when the visceral arteries have disease involvement. In this report we present a case where, despite having treated the entire length of the descending thoracic aorta, the dissection was maintained distally, leading to progression of the diameter of the aneurysm. After reviewing the literature, and to the best of our knowledge, we describe the first case in which renal autotransplant was performed to allow for subsequent exclusion of the aorta at the thoracoabdominal level using a fenestrated endoprosthesis for the celiac trunk and the superior mesenteric artery.

Respiration-induced deformations of the superior mesenteric and renal arteries in patients with abdominal aortic aneurysms

PURPOSE

To quantify respiration-induced deformations of the superior mesenteric artery (SMA), left renal artery (LRA), and right renal artery (RRA) in patients with small abdominal aortic aneurysms (AAAs).

MATERIALS AND METHODS

Sixteen men with AAAs (age 73 y ± 7) were imaged with contrast-enhanced magnetic resonance angiography during inspiratory and expiratory breath-holds. Centerline paths of the aorta and visceral arteries were acquired by geometric modeling and segmentation techniques. Vessel translations and changes in branching angle and curvature resulting from respiration were computed from centerline paths.

RESULTS

With expiration, the SMA, LRA, and RRA bifurcation points translated superiorly by 12.4 mm ± 9.5, 14.5 mm ± 8.8, and 12.7 mm ± 6.4 (P < .001), and posteriorly by 2.2 mm ± 2.7, 4.9 mm ± 4.2, and 5.6 mm ± 3.9 (P < .05), respectively, and the SMA translated rightward by 3.9 mm ± 4.9 (P < .01). With expiration, the SMA, LRA, and RRA angled upward by 9.7° ± 6.4, 7.5° ± 7.8, and 4.9° ± 5.3, respectively (P < .005). With expiration, mean curvature increased by 0.02 mm(-1) ± 0.01, 0.01 mm(-1) ± 0.01, and 0.01 mm(-1) ± 0.01 in the SMA, LRA, and RRA, respectively (P < .05). For inspiration and expiration, RRA curvature was greater than in other vessels (P < .025).

CONCLUSIONS

With expiration, the SMA, LRA, and RRA translated superiorly and posteriorly as a result of diaphragmatic motion, inducing upward angling of vessel branches and increased curvature. In addition, the SMA exhibited rightward translation with expiration. The RRA was significantly more tortuous, but deformed less than the other vessels during respiration.