Spontaneous gyrotropic electronic order in a transition-metal dichalcogenide.

Chirality is ubiquitous in nature, and populations of opposite chiralities are surprisingly asymmetric at fundamental levels1,2. Examples range from parity violation in the subatomic weak force to homochirality in biomolecules. The ability to achieve chirality-selective synthesis (chiral induction) is of great importance in stereochemistry, molecular biology and pharmacology2. In condensed matter physics, a crystalline electronic system is geometrically chiral when it lacks mirror planes, space-inversion centres or rotoinversion axes1. Typically, geometrical chirality is predefined by the chiral lattice structure of a material, which is fixed on formation of the crystal. By contrast, in materials with gyrotropic order3-6, electrons spontaneously organize themselves to exhibit macroscopic chirality in an originally achiral lattice. Although such order-which has been proposed as the quantum analogue of cholesteric liquid crystals-has attracted considerable interest3-15, no clear observation or manipulation of gyrotropic order has been achieved so far. Here we report the realization of optical chiral induction and the observation of a gyrotropically ordered phase in the transition-metal dichalcogenide semimetal 1T-TiSe2. We show that shining mid-infrared circularly polarized light on 1T-TiSe2 while cooling it below the critical temperature leads to the preferential formation of one chiral domain. The chirality of this state is confirmed by the measurement of an out-of-plane circular photogalvanic current, the direction of which depends on the optical induction. Although the role of domain walls requires further investigation with local probes, the methodology demonstrated here can be applied to realize and control chiral electronic phases in other quantum materials4,16.

Observation of the nonlinear Hall effect under time-reversal-symmetric conditions.

The electrical Hall effect is the production, upon the application of an electric field, of a transverse voltage under an out-of-plane magnetic field. Studies of the Hall effect have led to important breakthroughs, including the discoveries of Berry curvature and topological Chern invariants1,2. The internal magnetization of magnets means that the electrical Hall effect can occur in the absence of an external magnetic field2; this 'anomalous' Hall effect is important for the study of quantum magnets2-7. The electrical Hall effect has rarely been studied in non-magnetic materials without external magnetic fields, owing to the constraint of time-reversal symmetry. However, only in the linear response regime-when the Hall voltage is linearly proportional to the external electric field-does the Hall effect identically vanish as a result of time-reversal symmetry; the Hall effect in the nonlinear response regime is not subject to such symmetry constraints8-10. Here we report observations of the nonlinear Hall effect10 in electrical transport in bilayers of the non-magnetic quantum material WTe2 under time-reversal-symmetric conditions. We show that an electric current in bilayer WTe2 leads to a nonlinear Hall voltage in the absence of a magnetic field. The properties of this nonlinear Hall effect are distinct from those of the anomalous Hall effect in metals: the nonlinear Hall effect results in a quadratic, rather than linear, current-voltage characteristic and, in contrast to the anomalous Hall effect, the nonlinear Hall effect results in a much larger transverse than longitudinal voltage response, leading to a nonlinear Hall angle (the angle between the total voltage response and the applied electric field) of nearly 90 degrees. We further show that the nonlinear Hall effect provides a direct measure of the dipole moment10 of the Berry curvature, which arises from layer-polarized Dirac fermions in bilayer WTe2. Our results demonstrate a new type of Hall effect and provide a way of detecting Berry curvature in non-magnetic quantum materials.

Endosutured Aneurysm Repair of Abdominal Aortic Aneurysms with Short Necks Achieves Acceptable Midterm Outcomes-Results from the Peru Registry.

BACKGROUND: The study aims to describe midterm outcomes following treatment of infrarenal abdominal aortic aneurysms (AAAs) with short necks by endosutured aneurysm repair using the Heli-FX EndoAnchor system. METHODS: This is a retrospective study of prospectively collected data from 9 vascular surgery departments between June 2010 and December 2019, including treated AAAs with neck lengths ≤10 mm. The decision for the use of EndoAnchors was made by the treating surgeon or multidisciplinary aortic committee according to each center's practice. There were 2 Groups further assessed according to neck length, A (≥4 and <7 mm) and B (≥7 and ≤10 mm). The main outcomes analyzed were technical success, freedom from type Ia endoleaks (TIaELs), sac size increase, all-cause and aneurysm-related mortality. RESULTS: Seventy-six patients were included in the study, 17 fell into Group A and 59 into Group B. Median follow-up for the cohort was 40.5 (interquartile range 12-61) months. A median of 6 (interquartile range 3) EndoAnchors were deployed in each subject. Technical success was 86.8% for the total group, 82.4% and 88.1% (P = 0.534) for Groups A and B respectively. Six out of 10 (60%) of TIaELs at the completion angiographies showed spontaneous resolution. Cumulative freedom from TIaEL at 3 and 5 years for the total group was 89% and 84% respectively; this was 93% and 74% for Group A and 88% at both intervals in Group B (P = 0.545). In total, there were 7 (9.2%) patients presenting with TIaELs over the entire study period. Two (11.8%) in Group A and 5 (8.5%) in Group B (P = 0.679). There were more patients with sac regression in Group B (Group A = 6-35.3% vs. Group B = 34-57.6%, P = 0.230) with no statistical significance. All-cause mortality was 19 (25%) patients, with no difference (4-23.5% vs. 15-25.4%, P = 0.874) between groups; whereas aneurysm-related mortality occurred in 1 patient from Group A and 3 from Group B. CONCLUSIONS: This study demonstrates reasonable outcomes for patients with short-necked AAAs treated by endosutured aneurysm repair in terms of TIaELs up to 5-year follow-up. EndoAnchor use should be judiciously evaluated in short necks and may be a reasonable option when anatomical constraints are encountered, mainly for those with 7-10 mm neck lengths. Shorter neck length aspects, as indicated by the results from Group A, may be an alternative when no other options are available or feasible.

European Expert Opinion on Infrarenal Sealing Zone Definition and Management in Endovascular Aortic Repair Patients: A Delphi Consensus.

PURPOSE: The purpose of the study was to provide a consensus definition of the infrarenal sealing zone and develop an algorithm to determine when and if adjunctive procedure(s) or reintervention should be considered in managing patients undergoing endovascular aortic repair (EVAR) for infrarenal abdominal aortic aneurysm (AAA). METHODS: A European Advisory Board (AB), made up of 11 vascular surgeons with expertise in EVAR for AAA, was assembled to share their opinion regarding the definition of preoperative and postoperative infrarenal sealing zone. Information on their current clinical practice and level of agreement on proposed reintervention paths was used to develop an algorithm. The process included 2 virtual meetings and 2 rounds of online surveys completed by the AB (Delphi method). Consensus was defined as reached when ≥ 8 of 11 (73%) respondents agreed or were neutral. RESULTS: The AB reached complete consensus on definitions and measurement of the pre-EVAR target anticipated sealing zone (TASZ) and the post-EVAR real achieved sealing zone (RASZ), namely, the shortest length between the proximal and distal reference points as defined by the AB, in case of patients with challenging anatomies. Also, agreement was achieved on a list of 4 anatomic parameters and 3 prosthesis-/procedure-related parameters, considered to have the most significant impact on preoperative and postoperative sealing zones. Furthermore, the agreement was reached that in the presence of visible neck-related complications, both adjunctive procedure(s) and reintervention should be contemplated (100% consensus). In addition, adjunctive procedure(s) or reintervention can be considered in the following cases (% consensus): insufficient sealing zone on completion imaging (91%) or on the first postoperative computed tomography (CT) scan (91%), suboptimal sealing zone on completion imaging (73%) or postoperative CT scan (82%), and negative evolution of the actual sealing zone over time (91%), even in the absence of visible complications. CONCLUSIONS: AB members agreed on definitions of the pre- and post-EVAR infrarenal sealing zone, as well as factors of influence. Furthermore, a clinical decision algorithm was proposed to determine the timing and necessity of adjunctive procedure(s) and reinterventions.

Mid-term outcomes of the use of endoanchors during thoracic endovascular aortic repair in multicentre analysis.

OBJECTIVE: To describe mid-term outcomes of the use of EndoAnchors as an adjunct for arch and thoracic endovascular aortic repair (TEVAR). METHODS: A retrospective multicentre series from nine centres using the Heli-FX EndoAnchor System (Medtronic Inc, Minneapolis, USA) at TEVAR over May 2014-May 2019 is presented. The study is registered at ClinicalTrials.gov with number NCT04100499. The primary outcome was freedom from Type I endoleak at EndoAnchors deployments; secondary outcomes included evaluation of aortic wall penetration (AWP) at first computed tomography scan, EndoAnchor-related issues and mortality. RESULTS: 54 high-risk patients (35 males/19 females, age 73 ± 11 years) with arch, thoracic and thoracoabdominal aneurysmal disease (3 chronic post-dissection and one patch pseudoaneurysm), with a mean neck length 19.7 ± 6.6 mm that were treated with multiple hybrid and endovascular techniques were included. A total of 329 EndoAnchors were used with a mean of 6.1 ± 2.5 per patient. Overall adequate AWP was 86%, whereas arch (Ishimaru's zones 0-2) deployments achieved 80.6% when compared to 87.3% in descending thoracic aorta (dTA); although there was no statistical significance. Freedom from type I endoleaks was 88% at 2 year follow-up, due to 4 type IA endoleaks, two of them successfully treated, one with conservative treatment due to complexity of repair and remaining patient died 1 year later due to endograft infection. There were reported five EndoAnchor-related issues; four losses and one renal stent-graft was crushed due to catheter deflection solved with balloon reinflation. None of the losses had clinical significance. Overall mortality is described for 7 (9.5%) patients, one of them aneurysm-related. CONCLUSIONS: The adjunctive use of EndoAnchors in TEVAR and complex TEVAR procedures achieved acceptable outcomes at midterm in a high-risk series with hostile seal zones. Still, they should be still judiciously used as there is lack of data to suggest a more liberal use; therefore, the landing zone should not be compromised in favour of their use.

The Effect of EndoAnchors on Aneurysm Sac Regression for Patients Treated With Infrarenal Endovascular Repair With Hostile Neck Anatomies: A Propensity Scored Analysis.

PURPOSE: To analyze sac evolution patterns in matched patients with hostile neck anatomy (HNA) treated with standard endovascular aneurysm repair (sEVAR) and endosutured aneurysm repair (ESAR). METHODS: Observational retrospective study using prospectively collected data between June 2010 and December 2019. ESAR group data were extracted from the primary arm of the PERU registry with an assigned identifier (NCT04100499) at 8 centers and those from the sEVAR came from 4 centers. Suitability for inclusion required: no proximal endograft adjuncts (besides EndoAnchor use), ≤15 mm neck length and minimum of 12-months follow-up imaging. Bubble-shaped neck (noncylindrical short neck with discontinuous seal) aspect was analyzed. Both groups were analyzed using propensity score matching (PSM) for aortic neck length, width, angulation, and device fixation type. Main outcome assessed was sac evolution patterns (sac expansion and regression were defined as >5mm increase or decrease, of the maximum sac diameter respectively; all AAAs within this ±5 mm range in diameter change were considered stable) and secondary outcomes were type-Ia endoleaks; other endoleaks and mortality. A power analysis calculation >80% was confirmed for sac regression evaluation. RESULTS: After exclusions, PSM resulted in 96 ESAR and 96 sEVAR patients. Mean imaging follow-up (months) was 44.4±21.3 versus 43.0±19.6 (p=0.643), respectively. The overall number of patients achieving sac regression was higher in the ESAR group (n=57, 59.4% vs n=31, 32.3%; p<0.001) and the cumulative sac regression achieved at 5 years was 65% versus 38% (p=0.003) in favor of the ESAR group. There were no statistically significant differences in type-Ia endoleak and/or other endoleaks. Univariate analysis for sac regression patients in the sEVAR and ESAR group individually showed the bubble-shape neck as a predictor of sac regression failure. There were no statistical differences in overall and aneurysm-related mortality. CONCLUSION: Endosutured aneurysm repair provided improved rates of sac regression for patients with AAA and HNA when compared with sEVAR at midterm and up to 5 years, despite similar rates of type-Ia endoleaks, and the need to consider some important limitations. The presence of bubble-shaped neck was a predictor of sac regression failure for both groups equally. CLINICAL IMPACT: The use of EndoAnchors aids and improves EVAR treatment in hostile neck anatomies by an increased rate of sac regression when compared to EVAR treatment alone in up to 5 year analysis. Moreover, a trend to reduced number of type Ia endoleaks is also achieved, although not significant in the present study. This data, adds to current and growing evidence on the usefulness of EndoAnchors for AAA endovascular treatment.

Endovascular aortic repair with EndoAnchors demonstrate good mid-term outcomes in physician-initiated multicenter analysis-The PERU registry.

OBJECTIVES: We aim to describe real-world outcomes from multicenter data about the efficacy of adjunct Heli-FX EndoAnchor usage in preventing or repairing failures during infrarenal endovascular aneurysm repair (EVAR), so-called EndoSutured-aneurysm-repair (ESAR). METHODS: The current study has been assigned an identifier (NCT04100499) at the US National Library of Medicine (https://ClinicalTrials.gov). It is an observational retrospective study of prospectively collected data from seven vascular surgery departments between June 2010 and December 2019. Patients included in the ANCHOR registry were excluded from this analysis. The decision for the use of EndoAnchors was made by the treating surgeon or multidisciplinary aortic committee according to each center's practice. Follow-up imaging was scheduled according to each center's protocol, which necessarily included either abdominal ultrasound or radiography or computed tomographic scan imaging. The main outcomes analyzed were technical success, freedom from type Ia endoleaks (IaEL), all-cause and aneurysm-related mortality, and sac variation and trends evaluated for those with at least six months imaging follow-up. RESULTS: Two hundred and seventy-five patients underwent ESAR in participating centers during the study period. After exclusions, 221 patients (184 males, 37 females, mean age 75 ± 8.3 years) were finally included for analysis. Median follow-up for the cohort was 27 (interquartile range 12-48) months. A median 6 (interquartile range 3) EndoAnchors were deployed at ESAR, 175 (79%) procedures were primary and 46 (21%) revision cases, 40 associated with type IaEL. Technical success at operation (initial), 30-day, and overall success were 89, 95.5, and 96.8%, respectively; the 30-day success was higher due to those with subsequent spontaneous proximal endoleak seal. At two years, freedom from type IaEL was 94% for the whole series; 96% and 86% for the primary and revision groups, respectively; whereas freedom from all-cause mortality, aneurysm-related mortality, and reintervention was 89%, 98%, and 87%, respectively. Sac evolution pre-ESAR was 66 ± 15.1 vs. post ESAR 61 ± 17.5 (p < 0.001) and for 180 patients with at least six-month follow-up, 92.2% of them being in a stable (51%) or regression (41%) situation. CONCLUSIONS: This real-world registry demonstrates that adjunct EndoAnchor usage at EVAR achieves high rates of freedom from type IaEL at mid-term including in a high number of patients with hostile neck anatomy, with positive trends in sac-size evolution. Further data with longer follow-up may help to establish EndoAnchor usage as a routine adjunct to EVAR, especially in hostile necks.

Preoperative Planning for EndoAnchor Use During Thoracic Endovascular Aortic Repair in the Distal Aortic Arch.

PURPOSE: To describe steps related to intraoperative C-arm orientations that can be taken during preoperative planning of thoracic stent-graft repair to facilitate the deployment of EndoAnchors in the distal aortic arch. TECHNIQUE: Previous experience from transcatheter aortic valve implantation (TAVI) may be helpful in addressing issues with C-arm orientation. In TAVI, preoperative computed tomography (CT) images are routinely obtained to generate a patient-specific curve that represents a virtually complete rotation of the C-arm perpendicular to the annulus. The curve clearly demonstrates that each adjustment in cranial or caudal view needs parallax correction in the left or right anterior oblique direction to remain perpendicular, and vice versa. This experience can be translated to the preoperative planning of EndoAnchor use in the aortic arch. By placing markers along the circumference of the proximal landing zone of the preoperative CT scan, the required C-arm orientations can be determined for each marker. CONCLUSION: Determining the optimal C-arm orientation during preoperative planning will facilitate successful EndoAnchor deployment and may contribute to improved durability of endovascular repair in hostile necks in the aortic arch.

Multicenter Experience With Large Diameter Balloon-Expandable Stent-Grafts for the Treatment of Infrarenal Penetrating Aortic Ulcers.

PURPOSE: To describe the use of large-diameter balloon-expandable stent-grafts (BeGraft aortic stent-graft, Bentley InnoMed GmbH, Hechingen, Germany) in the treatment of infrarenal penetrating aortic ulcer (iPAU). MATERIALS AND METHODS: Retrospective analysis of patients undergoing endovascular treatment with the BeGraft aortic stent-graft in 8 European centers from January 2017 to October 2020. Demographics, perioperative data, and midterm outcomes were collected. Endpoints of the study were technical feasibility, early mortality, and morbidity. RESULTS: A total of 40 patients were included. The mean age was 73.9±7.05 years and 63.2% were male. Indications for treatment included size and morphology (65%), presence of symptoms (29.5%), and contained ruptures (5.5%). Urgent treatment was performed in 5% of cases. Technical success was 97.5%. Median operation time was 58 minutes (19-170 minutes), with 27.5% of patients having additional procedures during the main intervention (1 additional repair with a C-TAG (W.L. Gore & Associates, Inc, Flagstaff, AZ, USA) thoracic endoprosthesis, 5 covered endovascular reconstruction of aortic bifurcation procedures, 3 extensions with proximal cuffs, and 2 percutaneous angioplasties of the common iliac arteries). Percutaneous femoral access was used in 72.5%, while groin cut-down was performed in 27.5%. Repair was successful with only 1 stent in 45% of cases, while 37.5% required 2 stents and nearly 17.5% required 3/4 stent-grafts. The 30-day mortality was 0%, with a 2.5% reintervention rate (1 patient required evacuation of an intra-abdominal hematoma). Median follow-up was 13.9 months (2-39 months), during which no vascular-related reinterventions or deaths were reported. In 4 patients, a type II endoleak was observed. No cases of graft migration, thrombosis, or stent-fracture were observed. CONCLUSIONS: The treatment of iPAU with the BeGraft aortic stent-graft in a selective patient group is feasible with low rate of perioperative morbidity and mortality. Balloon-expandable stent-grafts offer the option to repair iPAUs with a shorter coverage of the aorta using low-profile sheath, that enables treatment in the presence of calcified access vessels and small diameter aortic bifurcations.

The Potential Relation Between polytetrafluoroethylene Grafts after Open Reconstructions for Abdominal Aortic Aneurysm and Perigraft Seromas.

BACKGROUND: The presence of sac enlargement after abdominal aortic aneurysm (AAA) open repair, a condition usually called perigraft seroma (PGS), nearly always has a benign behavior. Some theories implicated for PGS formation include coagulation abnormalities, fibroblast inhibition, low-grade infection, or improper graft handling. METHODS: This is a retrospective study including patients treated for AAA in 2 academic vascular surgery departments from 2007 to 2014, where 1 center preferably used polytetrafluoroethylene (PTFE) grafts whereas the preference of other center was mostly Dacron graft. The definition of PGS was conceived as a fluid collection around the graft on CT scan imaging with a radiodensity ≤25 Hounsfield units, reaching at least 30 mm in diameter and beyond the third postoperative month. Analysis was performed between patients with and without PGS. RESULTS: Seventy-eight patients met the inclusion criteria: 42 received Dacron and 36 PTFE grafts. Twenty-three (29.5%) patients accomplished the PGS diagnosis. Having a PTFE graft was the strongest factor for PGS formation on multivariate analysis. The medium seroma size was 42 mm (range, 30-90.6 mm) and the mean time from AAA repair to PGS detection was 26 months (range, 4-106 months). Three patients of the 23 with PGS required surgical repair, all of them were successfully treated: 2 by endovascular means and the remaining with explantation and Dacron reconstruction. CONCLUSIONS: PGS formation is not an unusual complication after open reconstructions for AAA treatment. This is especially true for PTFE grafts, and thus, closer follow-up is warranted if using this material. Treatment is clearly needed when symptoms appear; however, preventive strategies with either endovascular relining or reopen reconstructions require an individual approach counterbalancing benefits versus risk of the procedures.

Electrically Tunable Valley Dynamics in Twisted WSe_{2}/WSe_{2} Bilayers.

The twist degree of freedom provides a powerful new tool for engineering the electrical and optical properties of van der Waals heterostructures. Here, we show that the twist angle can be used to control the spin-valley properties of transition metal dichalcogenide bilayers by changing the momentum alignment of the valleys in the two layers. Specifically, we observe that the interlayer excitons in twisted WSe_{2}/WSe_{2} bilayers exhibit a high (>60%) degree of circular polarization (DOCP) and long valley lifetimes (>40 ns) at zero electric and magnetic fields. The valley lifetime can be tuned by more than 3 orders of magnitude via electrostatic doping, enabling switching of the DOCP from ∼80% in the n-doped regime to <5% in the p-doped regime. These results open up new avenues for tunable chiral light-matter interactions, enabling novel device schemes that exploit the valley degree of freedom.

Evaluation of EndoAnchor Aortic Wall Penetration After Thoracic Endovascular Aortic Repair.

Purpose: To analyze aortic wall penetration of Heli-FX EndoAnchors after use in seal zones in the aortic arch or descending thoracic aorta during thoracic endovascular aortic repair (TEVAR). Materials and Methods: From May 2014 to May 2019, 25 patients (mean age 70.5±10 years; 16 women) were treated with TEVAR and adjunctive use of the Heli-FX device in 3 academic vascular surgery departments. Computed tomography scans were retrospectively reviewed to determine the location [arch or descending thoracic aorta (DTA)] of the EndoAnchors and the adequacy of aortic wall penetration, defined as adequate (≥2 mm), partial (<2 mm), or inadequate wall penetration (including loss). Endoleaks, reinterventions, and mortality were assessed. Results: A total of 161 EndoAnchors were deployed (median 7 per patient, range 4-9). Twenty-two EndoAnchors were place in the arch (zones 0-2) and 139 in the DTA (zones 3-5). A larger proportion of arch deployments (27%) had suboptimal penetration compared with the DTA (6.5%; p<0.005), resulting in a 91% adequate wall penetration rate for the series overall. Three EndoAnchors were lost (and only 1 retrieved) in 3 different patients, with no additional morbidity; thus, an overall deployment success rate of 88% was achieved. At a mean follow-up of 16.6±14 months, 4 patients required 5 (successful) reinterventions, including one for a type Ia endoleak treated with chimney TEVAR. One patient died 10 months after treatment due to endograft infection, without an opportunity for surgical correction. Conclusion: EndoAnchors have a higher risk of maldeployment in the arch, though this may be attributable to the small learning curve experience in this location. The best aortic wall penetration for this series was in the DTA, where EndoAnchors proved useful for distal endograft fixation during TEVAR.

Systematic Review on the Use of Physician-Modified Endografts for the Treatment of Aortic Arch Diseases.

BACKGROUND: The total endovascular approach is in current evolution, and many series have described variable outcomes for branched technology, chimney techniques, or fenestrated repair; and even a combination of some of them. We aim to describe the current outcomes on physician-modified endograft for the treatment of arch diseases. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were used for this systematic review. The search was applied to MEDLINE, EMBASE, Google Scholar, and Cochrane Central Register of Controlled Trials. We used the following search terms in all possible combinations: home-made, physician-modified, surgeon-modified, on-table modification, hand-made, endograft, endovascular, aortic arch, and TEVAR: a thorough search of the English-language literature published until March 2020 was performed to identify studies using physician-modified endograft for the treatment of arch diseases. Only studies with treatment of 3 patients or more and with a minimum of 6-month follow-up were enrolled in the systematic review, whereas case reports were excluded from the analysis. RESULTS: Six articles participated in the systematic review after the exclusions, including a total of 239 patients for analysis. Four high-volume centers provided data including a high rate of single fenestrations in zone 2, accounting for nearly 70% of the cases. About 80.3% were males, and 67.4% received urgent treatment mainly for acute/subacute dissection (64.4%). Thoracic aortic aneurysm and/or postdissection arch aneurysm was the second leading cause of treatment with 25.9%. There was a technical success of 93.7% reaching up to 98.3% when additional procedures were performed. The 30-day mortality, stroke/transient ischemic attack, paraplegia, and stent-induced new entry rates were 2.9%, 2.1%, 0.4%, and 0.4%, respectively; whereas, overall mortality of the study was 4.6% at a mean follow-up of 33.2 ± 14.8 months. CONCLUSIONS: Endograft modification for aortic arch diseases' treatment demonstrates to be safe and highly effective, especially for aortic dissections needing single zone 2 fenestrations. Although outcomes achieved in the study seem encouraging, these are achieved at high-volume experienced centers, thus, they need to be judiciously evaluated, whereas proctoring may be a good alternative if one patient may benefit from the technique in an unexperienced center.

Partial Renal Coverage after Endovascular Aortic Aneurysm Repair with Suprarenal Fixation Seems Not to be Associated with Early Renal Impairment.

BACKGROUND: Efforts to achieve optimal seal during endovascular aortic aneurysm repair (EVAR) may produce partial coverage of the lowest renal artery and in some cases even occlusion. This coverage might alter the renal ostial flow, which could finally affect renal function. We sought to evaluate the incidence of renal ostium coverage and its possible effects on renal function. METHODS: All patients undergoing elective EVAR with suprarenal fixation devices between January 2014, and December 2017, at our institution were identified. Patients with preoperative and postoperative computed tomography angiography (CTA), as well as the preoperative, postoperative, and one year postintervention creatinine levels and estimated glomerular filtration rate (eGFR) were included in the present study. Patients in hemodialysis, with a preoperative eGFR <30 mL/min, urgent EVAR, neck adjunctive procedures, excessive aortic thrombus, or procedure-related reintervention were excluded. RESULTS: A total of 127 patients received EVAR for aortoiliac aneurysmatic pathologies between January 2014, and December 2017. Forty-three of them met the inclusion criteria having a median follow-up of 18.8 months (range; 12.0-53.9). Twenty-six (60.5%) patients presented at least one criterion of hostile neck condition and 23 (53.5%) had a preoperative eGFR <60 mL/min. The average distance from the proximal endograft fabric to the lower renal artery was 1.5 mm (range, 0.0-6.0) while a total of 15 renal ostia (34.9%) suffered unintended partial coverage (range, 20 to 75% of the renal ostium) in the postoperative CTA. Nine of these patients (60%) had a hostile neck condition. Eight patients (18.6%) suffered significant deterioration (>20% of the eGFR), 27 patients (62.8%) maintained their renal function and 8 (18.6%) presented an improvement of the eGFR in the latest available blood sample. Renal function impairment showed no significant association with renal ostium coverage (P = 0.561), hostile neck condition (P = 0.973), or the diameter of the renal artery (P = 0.835). In the subgroup analysis, patients with the eGFR <60 mL/min did not show significantly greater renal function deterioration (P = 0.568). CONCLUSIONS: Partial renal coverage is not an uncommon phenomenon occurring in one-third of the treated patients. However, it was not associated with renal function impairment in the early term. Further studies with longer follow-up are needed to confirm our results in the long haul.

Adapting Vascular Surgery Practice to the Current COVID-19 Era at a Tertiary Academic Center in Madrid.

BACKGROUND: The epidemic potential of coronavirus infection is now a reality. Since the first case detected in late 2019 in China, a fast worldwide expansion confirms it. The vascular patient is at a higher risk of developing a severe form of the disease because of its nature associating several comorbid states, and thus, some vascular surgery communities from many countries have tried to stratify patients into those requiring care during these uncertain times. METHODS: This is an observational study describing the current daily vascular surgery practice at one tertiary academic hospital in Madrid region, Spain-one of the most affected regions worldwide due to the COVID-19 outbreak. We analyzed our surgical practice since March 14th when the lockdown was declared up to date, May 14th (2 months). Procedural surgical practice, organizational issues, early outcomes, and all the troubles encountered during this new situation are described. RESULTS: Our department is composed of 10 vascular surgeons and 4 trainees. Surgical practice has been reduced to only urgent care, totaling 50 repairs on 45 patients during the period. Five surgeries were performed on 3 COVID-19-positive patients. Sixty percent were due to critical limb ischemia, 45% of them performed by complete endovascular approach, whereas less than 10% of repairs were aorta related. We were allocated to use a total of 5 surgical rooms in different locations, none our usual, as it was converted into an ICU room while performing 50% of those repairs with unusual nursery staff. CONCLUSIONS: The COVID-19 outbreak has dramatically changed our organization and practice in favor of urgent or semiurgent surgical care alone. The lack of in-hospital/ICU beds and changing nursery staff changed the whole availability organization at our hospital and was a key factor in surgical decision-making in some cases.

Expanded Suitability of Ruptured Abdominal Aortic Aneurysms for Total Endovascular Repair Using the Endurant Endograft and Heli-FX EndoAnchors.

PURPOSE: To assess if the suitability of endovascular aneurysm repair (EVAR) of ruptured abdominal aortic aneurysms (RAAAs) can be expanded by combining the Endurant stent-graft with the Heli-FX EndoAnchors. MATERIALS AND METHODS: Contrast-enhanced computed tomography (CT) scans of 90 patients (mean age 73.2±9 years; 87 men) with RAAA admitted between January 2014 and January 2018 in 2 tertiary care centers were analyzed in a 3-dimensional workstation. Anatomical features of the aneurysms according to the instructions for use (IFU) for the Endurant endograft were evaluated and expansion of treatment with Heli-FX EndoAnchors was assessed. RESULTS: Neck length <10 mm was present in 41 (45.6%) patients; 5 had neck diameters outside the IFU and 45 (50.0%) had conical necks. Thrombus and calcium were absent in 63 (70.0%) and 73 (81.1%), respectively. In the study cohort, 44 (48.9%) patients met all the neck criteria, although overall IFU compliance was found in only 35 (38.9%) patients due to iliac-related issues in 21 patients. The adjunctive use of EndoAnchors in the entire study group would enhance the therapeutic range to an additional 24 patients, 8 of whom would need an associated iliac procedure. This represents an expansion of the total EVAR approach from 48.9% to 75.6% of cases if some iliac issues are overcome and from 38.9% to 56.7% without correcting iliac deficiencies. CONCLUSION: The main reason of being unfit for endovascular treatment in this series was neck length <10 mm. Based on this analysis, nearly 40% of RAAA patients would have been candidates for EVAR based on the IFU neck criteria for the Endurant stent-graft. This suitability could be nearly doubled with the use of EndoAnchors and correction of unsuitable iliac anatomy. The use of EndoAnchors has the potential to offer a significant benefit in the endovascular treatment of RAAA patients.

Symptomatic Aortic Bare-Metal Stent Fracture after PETTICOAT Technique for Complicated Type B Aortic Dissection.

BACKGROUND: Aortic bare-metal stent rupture is an exceptional complication, associated with high risk of aorta rupture and death. We describe a successful endovascular approach for a symptomatic aortic bare-metal stent fracture after the provisional extension to induce complete attachment (PETTICOAT) technique. METHODS: A 53-year-old man with a complicated type B aortic dissection (visceral malperfusion) was treated with thoracic endovascular aortic repair (TEVAR) and "PETTICOAT" technique. The 1-, 6-, and 12-month follow-up scans showed progressive aortic remodeling. After 15 months from the initial procedure, the patient was admitted to the emergency department with severe thoracic pain and two syncopal episodes. Urgent angio-computed tomography (CT) showed bare-metal stent rupture and aortic dilatation to 45 mm at the site of stent fracture. RESULTS: He was urgently treated with TEVAR to cover the entire length of the bare-metal stent under local anesthesia and motor-evoked potential (MEP) monitoring. If signs of medullary ischemia are observed in the MEP register, a carotid-subclavian bypass was planned. At 12 months of follow-up, the patient remains asymptomatic. CT scan at 1 month and 12 months showed no signs of endoleak and aortic remodeling to 40 mm. CONCLUSIONS: Although unusual, this case demonstrates the possibility of material fatigue/failure and highlights the need of close imaging follow-up after TEVAR for treatment of aortic diseases.

Impact of the Aortic Graft on Arterial Stiffness and Inflammatory Biomarkers after Endovascular Aortic Repair or Open Surgical Repair in Abdominal Aortic Aneurysm Disease.

BACKGROUND: Abdominal aortic aneurysm (AAA) is an important cardiovascular (CV)-related disease that requires surgical treatment to prevent rupture. The elevation of arterial stiffness (AS) is an increasingly recognized independent determinant of CV morbidity and mortality and plays a special role in atherosclerosis. The importance of the surgical technique used for AAA repair in the long-term outcomes still needs to be clarified, and whether endovascular aortic repair (EVAR) or open surgical repair (OSR) confers high AS measurements and thus worse prognosis in terms of CV morbidity needs further investigation. METHODS: A prospective nonrandomized study that included consecutive patients requiring either EVAR or OSR for AAA disease between February 2015 and January 2016 was conducted. This study is registered on the National Institutes of Health website (ClinicalTrials.gov) and identified with NCT02642952. Several noninvasive measurements of AS and central aortic hemodynamics were obtained before surgery and in the first postoperative control (4-6 weeks), with change from baseline in heart rate-adjusted augmentation index (AIx@75) as main outcome. Likewise, inflammatory circulating biomarkers were also measured in the same time line. RESULTS: We included 44 patients, 25 in the EVAR group and 19 in the OSR group. Subjects who underwent EVAR were older and presented larger aneurysm diameter at baseline. There was a significant decrease in AIx@75 in the EVAR group after treatment (-4.1 ± 8.1%, P = 0.018), for a moderate effect size (d = 0.508), whereas the decreasing trend in the OSR group (-2.5 ± 6.7%, P = 0.127) was not statistically significant. No significant changes in carotid-radial pulse wave velocity (PWVCR) and central blood pressures were observed. The inflammatory markers increased after surgical repair, with significant changes in homocysteine in both EVAR (5.2 ± 6.9 µmol/L, P = 0.002) and OSR (1.8 ± 2.1 µmol/L, P = 0.002) groups. CONCLUSIONS: Our study suggests that both treatments confer better postoperative values of AS measured by AIx@75 and produces no changes in PWVCR, in the early term. Whether this situation is maintained during follow-up needs further investigation.

Multicenter Registry about the Use of EndoAnchors in the Endovascular Repair of Abdominal Aortic Aneurysms with Hostile Neck Showed Successful but Delayed Endograft Sealing within Intraoperative Type Ia Endoleak Cases.

BACKGROUND: The durability of endovascular aortic aneurysms repair (EVAR) is highly related to several anatomical constraints. The term "hostile neck" describes several anatomical features that usually make EVAR treatment technically demanding despite having higher risk of failure. The aim of the study was to describe a multicenter experience with EVAR and an adjunctive use of EndoAnchors in hostile neck anatomies. METHODS: Data were prospectively collected from 4 academic vascular centers including 46 patients with a hostile neck treated by standard EVAR with the adjunctive use of EndoAnchors. Twenty-two of them (47.8%, group A) had an intraoperative type Ia endoleak, and 24 (52.2%) patients were treated in a preventive manner (group B). Primary endpoints were technical and procedural success. Secondary endpoints were regression of the aneurysm sac, freedom from type Ia endoleak, and reinterventions. RESULTS: Neck length and diameter showed no statistical difference in preoperative measures, 9.1 ± 6.9 mm and 8.6 ± 2.8 mm and 25.4 ± 4.7 mm and 27.3 ± 4.7 mm, in group A and B, respectively. Aneurysm sac diameter decreased from 58.2 ± 8 mm and 57.9 ± 9.8 mm to 55.7 ± 8.5 mm and 53.8 ± 10.4 mm in group A and B; respectively, at the last computed tomography scan. Technical and procedural success was 97.8% and 100%, respectively, for group B. Group A showed persistence of type Ia endoleak at completion angiogram in 9 (40.9%) patients. Five of them showed early spontaneous sealing at the first (30 days) computed tomography angiography (CTA), and in the remaining 4, a delayed spontaneous sealing was diagnosed at 12-month CTA. No neck-related secondary procedures were performed. Overall survival was 91%. CONCLUSIONS: Our study shows that additional use of EndoAnchors can successfully improve the sealing of abdominal endografts in case of intraoperative type Ia endoleaks in hostile neck anatomies, representing a safe and effective endovascular alternative in our armamentarium. However, meticulous radiological follow-up is necessary because complete resolution of all observed intraoperative type Ia endoleaks was not observed until the 12-month CTA follow-up.