Early Results of Physician Modified Fenestrated Stent Grafts for the Treatment of Thoraco-abdominal Aortic Aneurysms

Midterm Results of Physician-Modified Stent Grafts for Thoracoabdominal and Complex Abdominal Aortic Aneurysms Repair

BACKGROUND

To assess midterm results of physician-modified stent grafts (PMSG) for the treatment of emergent complex abdominal and thoracoabdominal aortic aneurysms (TAAA) in high-risk patients.

METHODS

All consecutive patients with emergent complex abdominal or TAAA undergoing PMSG technique between January 2012 and July 2019 were retrospectively included. Indications for PMSG were symptomatic aneurysms and rapidly growing aneurysms >70 mm. Ruptured aneurysms were excluded.

RESULTS

Thirty-three patients (mean age: 74 +/- 11 years) were included. The mean aneurysm diameter was 76 +- 20 mm. Patients presented with TAAA (n = 20, 61%), complex abdominal aortic aneurysms (CAAA, n = 9, 27%), type I endoleak after previous endovascular aneurysm repair (n = 3, 9%) and intramural aortic hematoma (n = 1, 3%). Chimney technique was performed in addition to PMSG in seven cases (21%). Intraoperative adverse events were recorded in seven cases (35%) in the TAAA group and one case (11%) in the CAAA group. In-hospital mortality rate was 15% (n = 3) in the TAAA group and 11% (n = 1) in the CAAA group. Moderate to severe complications were recorded in 45% of cases (n = 15). Spinal cord ischemia occurred in two cases (6%, one case without residual deficit and one with minor motor deficit). One (3%) patient required transient hemodialysis. One patient presented with early aortic rupture and required an open conversion. The mean follow-up duration was 31 months (1-79). Overall survival estimates were 81.4% (95% confidence interval [CI]: 63.1.-91.2) at 1 year and 71.6% (95% CI: 52.6-84.1) at 2 years. Freedom from reintervention rates at 1 and 2 years were 61.2% (95% CI: 41.7-75.9) and 57.4% (95% CI: 37.9-72.8). Target vessel primary patency rates at 1 and 2 years were 99.2% (95% CI: 94.2-99.9) and 97.7% (95% CI: 90.7-99.4).

CONCLUSIONS

PMSG for high-risk patients with complex aneurysms provided acceptable technical success and excellent target vessel patency rates but were associated with a 12% in-hospital mortality rate. Reinterventions were frequent. This technique should be limited to selected high-risk patients for whom the risk of rupture in the short-term is deemed too high to wait for graft manufacturing of custom-made device.

Mid-term Outcomes of Physician-Modified Fenestrated or Branched Endovascular Repair for Post-dissection Thoracoabdominal Aortic Aneurysms

PURPOSE

To report the early experience and mid-term outcomes of physician-modified fenestrated or branched endovascular repair (PM-F/BEVAR) for patients with post-dissection thoracoabdominal aortic aneurysm (PD-TAAA).

METHODS

PD-TAAA patients treated with PM-F/BEVAR between December 2014 and September 2020 in our institution were retrospectively analyzed.

RESULTS

Out of the 39 patients, technical success defined as successful deployment of all stent grafts with patent target vessels (TVs) and exclusion of the lesion without type I or III endoleak was achieved in 35 patients (89.7%). A total of 126 TVs were successfully reconstructed. Thirty-day mortality was 0%. Seven major adverse events occurred including one acute kidney injury, four renal infarctions, one retroperitoneal hematoma and one left renal artery occlusion. Seven type II endoleak and three type III endoleak were detected. During a mean 29.4 ± 15.5 months follow-up period, the mortality was zero. Three renal arteries and one external iliac artery occluded in four patients. No other new onset major adverse event occurred. No patient required reintervention. One type II endoleak spontaneously resolved, while the remaining six remained stable. One early type III endoleak diminished, and one new type III endoleak occurred at 2 months. The primary patency of TV was 96.8% (120/124). Shrinkage or stability of aneurysm diameter can be observed in 38 patients (97.4%). The false lumen thrombosis rate was 89.7% (35/39).

CONCLUSIONS

The present study showed encouraging results of PM-F/BEVAR for treatment of PD-TAAAs.

LEVEL OF EVIDENCE

Level 4, Case Series.

Intraoperative endoprosthesis customization for repair of an aortoenteric fistula in an emergency context: a case report

Aortoenteric fistula is a severe clinical condition and its management remains a major technical challenge for surgeons. In these cases, the conventional surgical approach is associated with high rates of morbidity and mortality. Endovascular surgery is an excellent option in these cases, but considering that the aorta has been treated previously, anatomy may not be compatible with commercially available endovascular devices and so physician-modified endografts may be needed in urgent cases. The case reported involves a secondary aortoenteric fistula, treated on an emergency basis with endovascular techniques, using a physician-modified endograft.

Initial Results of Antegrade Laser Fenestrations Using Image Fusion Guidance and Company Manufactured Stent Grafts in Complex Aortic Aneurysm Repair

OBJECTIVE

The aim was to describe initial outcomes of physician modified stent grafts using antegrade laser fenestrations and image fusion guidance (LEVAR) and company manufactured custom made (CM) stent grafts for the treatment of complex abdominal aortic aneurysms (CAAAs), thoraco-abdominal aortic aneurysms (TAAAs) and type I endoleaks (T1ELs).

METHODS

This was a retrospective single centre study. All LEVAR and Zenith (Cook) CM stent graft procedures between 1 January 2012 and 31 December 2018 were reviewed. Endpoints included intra-operative adverse events (IOAEs), in hospital mortality, re-interventions, target vessel patency, and 12 month outcomes (overall survival, freedom from re-intervention, target vessel patency). Outcomes at 12 months were estimated using the Kaplan-Meier method.

RESULTS

A hundred patients were identified and included in the study. All patients were deemed unfit for open repair. The cohort included 22 LEVAR and 78 CM stent grafts. LEVAR cases included painful aneurysms (n = 5), > 65 mm aneurysms (n = 10), anatomical constrains and/or presence of previous renal stents (n = 7) or cases declined by the manufacturer planning centre (n = 2). IOAEs were recorded in 41% of cases (n = 9) in the LEVAR group vs. 10% (n = 8, p = .002) in the CM group. The in hospital mortality rate in the LEVAR group was 9% (n = 2) vs. 4% (n = 3, p = .30) in the CM group. The median follow up duration was 22 months (7 - 38) in the LEVAR group and 28 months (11 - 78) in the CM group. The estimate of overall survival at one year was 91% in both groups. The freedom from re-intervention rate at one year was 58% in the LEVAR group vs. 87% in the CM group. The target vessel patency rates at one year were 95% in both groups.

CONCLUSION

In high risk patients deemed unfit for open repair, LEVAR may provide satisfactory 12 month overall survival and target vessel patency rates, though reported IOAE, mortality, and re-interventions rates were high thus requiring close and extensive follow up.

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.

Comprehensive Review of Physician Modified Aortic Stent Grafts: Technical and Clinical Outcomes

OBJECTIVE

Physician modified stent grafts (PMSGs) present satisfactory results in selected cases of complex aortic pathologies. However, the technique lacks standardisation and depends on the surgeon and aortic segment. The aim of this article is to review comprehensively the technical details and clinical results of PMSGs related to patients with pathology in all aortic locations.

METHODS

A MEDLINE search (last search 20 April 2020) identified 20 relevant papers in the English language published over the last 20 years evaluating clinical outcomes after a PMSG and specifying the technical details to design it.

RESULTS

Seven hundred and eleven patients were included in the analyses, with 59% being operated on as an emergency. Ninety-two per cent of abdominal aortic segment PMSGs (A-PMSGs) were performed either as an emergency or before 2012. The main indications were available in 670 cases; 435 were degenerative aneurysms (64.9%) and 171 were aortic dissections (25.5%). Most of the endografts used were composed of polyethylene terephthalate, except for the Ankura (expanded polytetrafluoroethylene [Lifetech Scientific, Shenzhen, China]; n = 50, 7.5%). The Valiant (Medtronic, Minneapolis, MN, USA) represented 65% (n = 169) of aortic arch PMSGs (aa-PMSGs) and the Zenith platform (Cook Medical, Bloomington, IN, USA) 51% (n = 139) of A-PMSGs. A snare was used to reinforce the fenestration in 458 PMSGs (66%) and a cautery device cut the fenestration in 484 (75%) PMSGs. No bridging stent was used in 47 (7.0%) PMSGs (these aa-PMSGs had large fenestrations). Technical success ranged from 87.5% to 100% and 30 day mortality from 0% to 8%. Primary branch patency ranged from 96.3% to 100% at 12 month follow up. Zero to 14% of patients experienced type 3 or type 1 endoleak at 14.8 month follow up.

CONCLUSION

PMSG is a useful technique, particularly when validated treatments are not available. However, it is a non-standardised technique and the long term consequences of modifications remain unknown.

Experience with physician-modified Ankura™ endografts for endovascular repair of thoracoabdominal aortic aneurysms

BACKGROUND

The aim of this study was to evaluate the early results of fenestrated/branched endovascular aortic repair (F/B-EVAR) of thoracoabdominal aortic aneurysms (TAAAs) using physician-modified Ankura^™ endografts (PMEGs).

METHODS

Sixteen consecutive patients who underwent F/B-EVAR using PMEGs between July 2017 and December 2018 were retrospectively reviewed. The perioperative mortality and morbidity of the PMEG technique were assessed, and the early results of follow-up were evaluated.

RESULTS

The median age of the patients was 75.3 years old (range: 48-83 years), and 12 (75.0%) patients were male. The median TAAA diameter was 7.1±1.5 cm (range: 5.1-11 cm). The initial technical success rate of vessel revascularization was 98.2% (55 of 56). Target vessel patency was 98.1% (52/53), and freedom from reintervention was 98.1% (52/53) at follow-up. The 30-day mortality rates 6.3%. There was no death during follow-up.

CONCLUSIONS

PMEGs represent an important innovation, with favorable initial results, in the treatment of patients with complex TAAAs who may be unfit for open repair. In addition, they remain a promising option for high-risk patients in need of urgent repair who cannot wait for a custom-made device.

An Innovative Customized Stent Graft Manufacture System Assisted by Three-Dimensional Printing Technology

BACKGROUND

Commercially available thoracic aortic stent grafts rarely match the geometric characteristics of the aorta perfectly, which can lead to complications. Customization maybe a solution for this problem, but the delay inherent in the current manufacturing process makes it unable to meet the urgent requirement of acute aortic events. We established and optimized a rapid design and manufacture system for a customized aortic stent graft assisted by 3-dimensional (3D) printing technology. We also evaluated the preliminary feasibility and capability of this customized stent graft.

METHODS

Seven essential production steps comprised the rapid design and manufacture process for the customized stent graft system assisted by 3D printing technology. Optimization of the manufacture process was refined over time in 3 stages. Bench test and in vivo experiments were used to verify the feasibility of this system and evaluate the preliminary usability of the customized stent graft.

RESULTS

After optimization, the theoretical production time of the customized stent graft was reduced to approximately 12 hours. Bench test showed radial forces against the aorta wall were better distributed in the customized stent graft than in the control stent graft. In vivo experimental results showed that the customized stent graft system worked effectively.

CONCLUSIONS

It was feasible to rapidly design and manufacture a customized aortic stent graft assisted by 3D printing technology, which demonstrated better geometric compliance and physical characters in the bench test and in in vivo experimentation. The manufacturing process could be accelerated to approximately 12 hours, which might be optimized further to meet urgent clinic requirements.

Comparison of Physician-Modified Fenestrated/Branched Stent-Grafts and Hybrid Visceral Debranching Plus Stent-Graft Placement for Complex Thoracoabdominal Aortic Aneurysm Repair

Purpose: To evaluate the immediate postoperative and midterm outcomes of complex thoracoabdominal aortic aneurysm (TAAA) treatment with fenestrated/branched physician-modified endovascular grafts (PMEGs) or open debranching of the visceral aorta with bypass graft revascularization plus endovascular aneurysm exclusion (hybrid repair). Materials and Methods: A retrospective analysis was conducted of 88 patients (mean age 70.0±10.6 years; 73 men) with complex TAAAs who underwent treatment with PMEGs (60, 68%) or a hybrid technique (28, 32%) between 2016 and 2019. The mean aneurysm diameter was 64.5±11.7 mm, and 37 patients (42%) were symptomatic. The Zenith TX2 and Ankura were the main stent-grafts used in the PMEG group. The hybrid technique involved visceral debranching with extra-anatomical bypass graft revascularization and subsequent stent-graft deployment (1- or 2-stage procedure). Results: In the PMEG group, 35 patients received modified stent-grafts with 4 fenestrations, 8 patients had 4 branches per device, and 17 patients had combinations (50 fenestrations and 18 branches) that successfully revascularized 228 of the 240 targets (95%). In the 28 hybrid cases, all 110 target vessels were successfully revascularized with bypass grafts. The overall 30-day mortality was 3.4% (2 PMEG and 1 hybrid), and the early rate of target vessel stenosis/occlusion was 3.3% (5 in PMEG group and 6 in the hybrid repair group). The 30-day morbidity was mainly attributed to pulmonary complications (15%), lower limb ischemia (8%), or spinal cord ischemia with paraplegia (6%). Eleven patients (13%) had deteriorated renal function with a >30% decrease in the glomerular filtration rate. The mean follow-up was 22.3±4.9 months, and mortality was 4.5% (3.3% in the PMEG group vs 7.1% in the hybrid repair group). Conclusion: PMEGs and hybrid techniques seem to be feasible treatment options for aortic aneurysms necessitating visceral vessel revascularization. PMEGs may have a lower morbidity than the hybrid technique, which nonetheless remains an important option available for complex aortic aneurysms.

Consecutive failing proximal landing zones

We report the case of a 77-year-old man who presented with successive aortic aneurysms during a 12-year period. He was first treated in 2006 for an abdominal aortic aneurysm with a bifurcated endograft, then in 2016 for a tender type IV thoracoabdominal aortic aneurysm with a proximal aortic cuff with in situ laser fenestrations. He presented in 2018 with a 9-cm distal thoracic aorta aneurysm managed by an off-the-shelf t-Branch endograft (Cook Medical, Bloomington, Ind). The perioperative course was uneventful, and 6-month follow-up computed tomography scan has shown freedom from endoleaks and branch patency. This case illustrates that apparently “healthy” aortic necks can degenerate after endovascular aneurysm repair.

Current status of endovascular treatment for thoracoabdominal aortic aneurysms

Open surgical repair (OSR) for thoracoabdominal aortic aneurysms (TAAAs) is maximally invasive and associated with high rates of operative mortality and perioperative complications including spinal cord ischemia (SCI), despite improvements in surgical techniques and perioperative care. Elderly patients, patients with a history of aortic surgery, and patients with severe comorbidities are often considered ineligible for this surgery and endovascular treatment may be their only treatment option. Total endovascular aneurysm repair (t-EVAR) without debranching surgery does not require thoracotomy and laparotomy and could improve the outcomes of these patients. t-EVAR includes fenestrated EVAR (f-EVAR), multi-branched EVAR (b-EVAR), and physician-modified fenestration endograft (PMFG). Although these techniques have achieved lower mortality rates than OSR, there are concerns about perioperative complications including limb ischemia, SCI, and long-term outcomes such as endograft migration and endoleaks (ELs). This article provides an overview of available endovascular devices for TAAAs and reviews the short and mid-term results of t-EVAR, as well as alternative options.

Intraoperative adverse events and early outcomes of custom-made fenestrated stent grafts and physician-modified stent grafts for complex aortic aneurysms

OBJECTIVE

Physician-modified fenestrated stent grafts (PMSGs) are a useful option for urgent or semiurgent treatment of complex abdominal aortic aneurysms (CAAAs). The aim of this study was to describe in-hospital outcomes of custom-made fenestrated stent grafts (CMSGs) and PMSGs for the treatment of CAAAs and thoracoabdominal aortic aneurysms (TAAAs).

METHODS

In this single-center, retrospective study, all consecutives patients with CAAAs or TAAAs undergoing endovascular repair using Zenith CMSGs (Cook Medical, Bloomington, Ind) or PMSGs between January 2012 and November 2017 were included. End points were intraoperative adverse events, in-hospital mortality, postoperative complications, reinterventions, target vessel patency, and endoleaks.

RESULTS

Ninety-seven patients were included (CMSGs, n = 69; PMSGs, n = 28). The PMSG group included more patients assigned to American Society of Anesthesiologists class 4 (n = 14 [50%] vs n = 16 [23%]; P = .006) and more TAAAs (n = 17 [61%] vs n = 10 [15%]; P < .0001). Intraoperative adverse events were recorded in eight (11%) patients in the CMSG group vs six (21%) patients in the PMSG group. No intraoperative death or open conversion occurred. In-hospital mortality rates were of 4% (n = 3) in the CMSG group and 14% in the PMSG group (n = 4). Chronic renal failure was an independent preoperative risk factor of postoperative death or complications (odds ratio, 4.88; 95% confidence interval, 1.65-14.43; P = .004). Rates of postoperative complications were 22% (n = 15) and 25% (n = 7) in the CMSG and PMSG groups. Spinal cord ischemia rates were 4% (n = 3) and 7% (n = 2) in the CMSG and PMSG groups. Reintervention rates were 16% (n = 11) in the CMSG group and 32% (n = 9) in the PMSG group. At discharge, target vessel patency rate in CMSGs was 98% (n = 207/210). All target vessels (n = 98) were patent in the PMSG group. Endoleaks at discharge were observed in 24% of the CMSG group (n = 16) vs 8% of the PMSG group (n = 2).

CONCLUSIONS

Our study showed clinically relevant differences of several important in-hospital outcomes in the CMSG and PMSG groups. Larger cohorts and longer follow-up are needed to allow direct comparison. PMSGs may offer acceptable in-hospital results in patients requiring urgent interventions when CMSGs are not available or possible.

Hybrid Repair of an Innominate Artery Mycotic Aneurysm with an "On-The-Table" Customized Endograft

BACKGROUND

The objective of this report is to present a challenging case of a mycotic aneurysm of the innominate artery (IA) in a patient with a bovine aortic arch.

MATERIALS AND METHODS

An 85-year-old woman presented with intermittent fever and positive blood cultures for Staphylococcus aureus. An echocardiogram and a positron emission tomography-computed tomography were performed, showing a hypermetabolic dilation of the IA compatible with a mycotic aneurysm with a type one bovine aortic arch. Conventional open arch repair and total endovascular repair with a custom-made aortic endograft were rejected given the elderly age and need for urgent repair. Treatment was achieved with a hybrid procedure, including a left carotid transposition and exclusion of the aneurysm with a modified Endurant II^® iliac limb (two stents were cut off and it was resheathed in an inverted fashion) released through a prosthetic graft sutured onto the right axillary artery, followed by coil embolization of the sac. One year after the repair, the patient is well with complete exclusion of the aneurysm.

CONCLUSIONS

Under the need for urgent repair, "on-the-table" modification of standard endograft components can be an effective solution for aneurysm exclusion when off-the-shelf endovascular stent grafts do not meet the anatomical requirements.

Treatment of Visceral Transplant Pseudoaneurysms Using Physician-Modified Fenestrated Stent Grafts: Initial Experience

Pseudoaneurysms after visceral transplantation represent a significant risk to patients. We report the successful treatment of three transplant (pancreas, liver and kidney) artery anastomotic pseudoaneurysms using physician-modified fenestrated endovascular stent grafts. In all cases, surgical repair was considered high risk and would have compromised the arterial supply to the graft. The endovascular approach in all cases obviated the need for surgical intervention and maintained graft arterial supply.

Fenestrated Thoracic Endovascular Aortic Repair Using Physician-Modified Stent Grafts (PMSGs) in Zone 0 and Zone 1 for Aortic Arch Diseases

PURPOSE

To evaluate the outcomes of fenestrated thoracic endovascular aortic repair (f-TEVAR) using physician-modified stent grafts (PMSGs) in zone 0 and zone 1 for aortic arch diseases.

METHODS

f-TEVAR using PMSGs in Z0 and Z1 was performed on ten high-risk patients for open surgery from November 2015 to September 2017. Indications were complicated acute type B dissection (ABAD) with retrograde dissection involving the mid-arch (n = 1), distal arch aneurysms (n = 3), mid-arch aneurysms of the inner arch curvature (n = 3) and penetrating aortic ulcer located in the mid- or proximal arch (n = 3). Pre-, intra- and postoperative clinical data were recorded.

RESULTS

The median patient age was 61 (range 45-81) years, and 9 (90%) patients were men. Ten PMSGs (Medtronic Valiant stent grafts, n = 1; Relay thoracic stent grafts, n = 4; Cook TX2 device, n = 5) were deployed. PMSGs were deployed from Z0 and Z1 in 5 and 5 patients, respectively. Double small fenestrations for the left subclavian artery (LSA) and the left common carotid artery (LCCA), respectively, were created in 3 patients. Triple small fenestrations for the innominate artery (IA), the LCCA and the LSA, respectively, were created in 2 patients. One large fenestration for both the IA and the LCCA combined with one small fenestration for the LSA was created in 3 patients. One large fenestration for the LCCA combined with one small fenestration for the LSA was created in 2 patients. Posterior diameter-reducing ties were added to all the devices except to one Valiant stent graft. All but 2 patients underwent elective procedure. Median duration for stent graft modifications was 105 (range 90-125) min. The technical success rate was 90%. Overall mortality was 10% (1/10). One patient died of sudden cardiac arrest intraoperatively after the deployment of the PMSG and all the supra-aortic branch stents. Mean operative time was 106.0 ± 43.0 min, and fluoroscopy time was 30.6 ± 22.9 min. There were no type I or type III endoleaks, perioperative neurological complications or spinal cord ischemia. Median length of stay was 8 (range 4-35) days. Nine patients survived at mean 13.3 (range 6.0-19.0) months follow-up. Retrograde dissection occurred in one patient of Z0 group 40 days post-f-TEVAR and resolved after open repair. During follow-up, all target vessels remained patent without fenestration-related type I or III endoleaks.

CONCLUSIONS

f-TEVAR using PMSGs in Z0 and Z1 for the treatment of aortic arch diseases in high-risk patients is feasible in the hands of experienced operators.

Physician-Modified Fenestrated Endografts for Managing the Ruptured or Symptomatic Aortic Aneurysm: Technique Overview and Clinical Outcomes

PURPOSE:

Fenestrated endovascular aneurysm repair (FEVAR) grafts have a 10- to 12-week manufacturing time and are generally not available for emergency cases of symptomatic or ruptured aortic aneurysm. In the absence of other alternatives, conventional off-the-shelf stent grafts can be modified by trained operators to treat these complex cases. The aim of this study is to present a single-center experience of physician-modified FEVAR.

METHODS:

A retrospective review was performed of all physician-modified FEVAR identified from the hospital endovascular database at a single tertiary referral center between September 1996 and September 2017.

RESULTS:

Eight cases of urgent or emergency endovascular aneurysm repair (EVAR) with physician-modified grafts were identified. Mean follow-up was 44 weeks (range: 5-106 weeks). Outcomes for all implanted grafts (7/8 cases) included 100% technical success, 14% rate of endoleak, no procedure-related complications, no adverse visceral events, 0% 30-day mortality and 100% 1-year target vessel patency, and freedom from aneurysm-related death. There was a 14% (1/7 cases) per patient reintervention rate.

CONCLUSION:

Modifying EVAR grafts is a highly technical process requiring meticulous planning and extensive elective experience with FEVAR. The current series demonstrates that physician modification of endografts for urgent or emergency abdominal aortic aneurysm repair is feasible and a safe alternative to open surgical aneurysm repair.

[Acute aortic syndromes]

Acute aortic syndromes include aortic dissections, intramural hematomas, penetrating ulcers, ruptured or contained ruptured aortic aneurysms. In presence of acute thoracic or dorsal pain, elevated D-Dimers and if acute coronary artery syndrome has been ruled out, additional imaging should be performed to detect acute aortic pathologies. Acute type A dissections involve the ascending aorta. Emergent open repair is the preferred treatment. Acute type B dissections involve the thoracic descending aorta. Endovascular treatment using thoracic stent grafts is indicated in complicated cases (malperfusion, rupture, uncontrolled hypertension) or in cases where risk factors of aortic degeneration are identified. Regarding ruptured abdominal aortic aneurysms, optimization techniques recently led to a reduced postoperative mortality. They include adequate treatment of abdominal compartment syndrome, use of aortic stent grafts, endovascular balloon occlusion and permissive hypotension. Symptomatic complex aneurysms encompass renal and visceral arteries. Nowadays, they can be treated in an urgent setting using new endovascular techniques, such as "off-the shelf" branched stent grafts, parallel techniques, home made or in situ fenestrations of standard stent grafts.

Feasibility of using bulk metallic glass for self-expandable stent applications

Self-expandable stents are widely used to restore blood flow in a diseased artery segment by keeping the artery open after angioplasty. Despite the prevalent use of conventional crystalline metallic alloys, for example, nitinol, to construct self-expandable stents, new biomaterials such as bulk metallic glasses (BMGs) are being actively pursued to improve stent performance. Here, we conducted a series of analyses including finite element analysis and molecular dynamics simulations to investigate the feasibility of using a prototypical Zr-based BMG for self-expandable stent applications. We model stent crimping of several designs for different percutaneous applications. Our results indicate that BMG-based stents with diamond-shaped crowns suffer from severe localization of plastic deformation and abrupt failure during crimping. As a possible solution, we further illustrate that such abrupt failure could be avoided in BMG-based stents without diamond shape crowns. This work would open a new horizon for a quest toward exploiting superior mechanical and functional properties of metallic glasses to design future stents. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1874-1882, 2017.