Secondary Vessel Research Articles

Effect of connected vessels structure on methane explosion characteristics

The effects of connected vessels structure (pipe bending position and angle, vessel shape and volume) and bifurcated pipe on methane explosion characteristics were experimentally researched. Six explosion vessels with different volumes and shapes and a series of bending pipes were adopted respectively. Results indicate that the explosion pressure inside the whole connected vessels presented a trend of rising firstly and then decreasing with the decrease of pipe bending angle. And the increases of primary and secondary volumes could result in the greater explosion pressure inside the two vessels, and the effect of spherical vessel was more significant compared with the cylindrical vessel of same volume. Although the effect of spherical vessel on the pressure rising rate was greater than that of the cylindrical vessel, the effect of smaller volume vessel was more significant. As bifurcated pipe existed, part of the flame and pressure wave was shunted, resulting in the energy weakening, after flame propagation to the secondary vessel. Due to the combined effect of the turbulence enhancing and shunt weakening, different explosion pressures were presented inside the connected vessels under T-L-R, T-L-B and S-T connection forms. Besides, the bending angle of bifurcated pipe also could affect the shunt extents of flame and pressure wave, further affecting the explosion pressure and flame propagation inside the main pipe.

A cadaveric study on the origins of the uterine artery

The uterine artery (UA) is a visceral branch from the anterior division of the internal iliac artery (IIA). Knowledge of the variant origins of this artery is critical during radiologic and surgical procedures of the pelvis, especially those involving the uterus, where managing blood flow is vital. Though its path and destination are well agreed upon, the origin of the UA differs notably, and has led many anatomists to create numerous descriptions for the distinctive variation. This project investigated the origin of the UA in the unique South Texas population of female cadavers donated to the UT Health San Antonio and established a fundamental and comprehensive classification system of the origin of this vessel which readily accommodates previous systems while improving its descriptive terminology. As the UA was identified, its origin was classified into three different ranks—primary, secondary, or tertiary. Primary‐ranked vessels originated directly from the internal iliac artery (IIA) and took three different formations as a separate branch, bifurcation with another vessel, or trifurcation with two other vessels. Secondary‐ranked UAs originated from primary vessels and tertiary‐ranked vessels originated from secondary vessels. 58.97% (23/39) of the UAs studied arose from the IIA as a primary‐ranked vessel, 38.5% (15/39) as a secondary rank, and 2.6% (1/39) as a tertiary rank. 21.7% (5/23) of primary‐ranked UAs took origin from IIA as a separate branch, 56.5% (13/23) as bifurcation with another vessel and 21.7% (5/23) as trifurcation with two other vessels. The UA originated as a bifurcation with the umbilical artery (UmbA) in 13/13 cases. UA origin as a trifurcation was observed in 3 different patterns: 40% (2/5) with the UmbA and the superior vesical artery (SVA); 40% (2/5) with the UmbA and vaginal artery (VA); 20% (1/5) with SVA and the internal pudendal artery (IPA). 93.3% (14/15) of secondary‐ranked UA arose from the UmbA and 6.7% (1/15) from the IPA. We observed a single tertiary ranked UA arising from the vaginal artery (VA), which took origin from the UmbA, a branch of the anterior division of the IIA. It is imperative that the prevalence of these primary‐ranked UA bifurcations and trifurcations be further established since permanent occlusion at the vessel’s origin may subsequently lead to necrosis of unintended tissues. Larger sample sizes amongst differing populations may lead to the discovery of uncommon bifurcation and trifurcation patterns, or with similar vessels in differing proportions. It would also be important to translate the evaluation criteria used in this study into 3D and 4D digital subtraction angiography or cone‐beam computed tomography software for clinical studies. Increasing awareness of the variant origins of the UA will ultimately improve patient treatment outcomes, particularly for female reproductive health.

Distinctive wood anatomy of early-diverging Asteraceae: Barnadesioideae

Abstract Asteraceae subfamily Barnadesioideae (ten genera, c. 90 species), confined to South America, are sister to the remainder of the family. The relative antiquity of the barnadesioids might lead one to expect that they contain more wood features plesiomorphic for the family, but only one character clearly falls in that category. Pits on imperforate tracheary elements are bordered (except for annuals), whereas simple pits occur in two related families, Calyceraceae (part) and Stylidiaceae (all that have been examined); in Goodeniaceae bordered pits only occur. By attaining fully bordered pits in Chuquiraga, the imperforate tracheary elements qualify as an apomorphy, ‘neotracheids’, valuable for resisting embolism formation in dry and cold South American habitats. Neotracheids are found also in Loricaria (Asteraceae: Inuleae), also from these habitats. Neotracheids, like plesiomorphic tracheids, are conductive, unlike fibre tracheids and libriform fibres. Other barnadesioid wood characters adapted to cold and drought include grouping of vessels, high vessel density, shorter vessel elements and helical sculpture (including helical thickenings on lumen-facing walls) of secondary xylem vessels. In Chuquiraga and Dasyphyllum, these helical thickenings are bordered in some species (new report for angiosperms). Some of the barnadesioid adaptations to cold and drought can be found in North American Artemisia spp. (Asteraceae: Anthemideae), especially in montane and desert areas. Wood features of barnadesioids match their respective habits and habitats: a few trees; shrubs of humid, dry or desert areas; a distinctive rhizomatous succulent in the pampas (Schlechtendalia); a scree/gravel perennial (Huarpea) and two genera of annuals, one with succulent leaves (Duseniella) and one with rayless (at least at first) stems in arid and open soils (Doniophyton). Diversity is unusual considering the small size of the subfamily. Examples of endodermal crystals (Arnaldoa only), pith sclereids and primary xylem fibres are cited.

Virtual Flow-T Stenting for Two Patient-Specific Bifurcation Aneurysms.

The effective treatment of wide necked cerebral aneurysms located at vessel bifurcations (WNBAs) remains a significant challenge. Such aneurysm geometries have typically been approached with Y or T stenting configurations of stents and/or flow diverters, often with the addition of endovascular coils. In this study, two WNBAs were virtually treated by a novel T-stenting technique (Flow-T) with a number of braided stents and flow-diverter devices. Multiple possible device deployment configurations with varying device compression levels were tested, using fast-deployment algorithms, before a steady state computational hemodynamic simulation was conducted to examine the efficacy and performance of each scenario. The virtual fast deployment algorithm based on a linear and torsional spring analogy is used to accurately deploy nine stents in two WNBAs geometries. The devices expand from the distal to proximal side of the devices with respect to aneurysm sac. In the WNBAs modelled, all configurations of Flow-T device placement were shown to reduce factors linked with increased aneurysm rupture risk including aneurysm inflow jets and high aneurysm velocity, along with areas of flow impingement and elevated wall shear stress (WSS). The relative position of the flow-diverting device in the secondary daughter vessel in the Flow-T approach was found to have a negligible effect on overall effectiveness of the procedure in the two geometries considered. The level of interventionalist-applied compression in the braised stent that forms the other arm of the Flow-T approach was shown to impact the aneurysm inflow reduction and aneurysm flow pattern more substantially. In the Flow-T approach the relative position of the secondary daughter vessel flow-diverter device (the SVB) was found to have a negligible effect on inflow reduction, aneurysm flow pattern, or WSS distribution in both aneurysm geometries. This suggests that the device placement in this vessel may be of secondary importance. By contrast, substantially more variation in inflow reduction and aneurysm flow pattern was seen due to variations in braided stent (LVIS EVO or Baby Leo) compression at the aneurysm neck. As such we conclude that the success of a Flow-T procedure is primarily dictated by the level of compression that the interventionalist applies to the braided stent. Similar computationally predicted outcomes for both aneurysm geometries studied suggest that adjunct coiling approach taken in the clinical intervention of the second geometry may have been unnecessary for successful aneurysm isolation. Finally, the computational modelling framework proposed offers an effective planning platform for complex endovascular techniques, such as Flow-T, where the scope of device choice and combination is large and selecting the best strategy and device combination from several candidates is vital.

Perceived Limits of Endovascular Treatment for Secondary Medium-Vessel-Occlusion Stroke.

Thrombus embolization during mechanical thrombectomy occurs in up to 9% of cases, making secondary medium vessel occlusions of particular interest to neurointerventionalists. We sought to gain insight into the current endovascular treatment approaches for secondary medium vessel occlusion stroke in an international case-based survey because there are currently no clear recommendations for endovascular treatment in these patients. Survey participants were presented with 3 cases involving secondary medium vessel occlusions, each consisting of 3 case vignettes with changes in the patient's neurologic status (improvement, no change, unable to assess). Multivariable logistic regression analyses clustered by the respondent's identity were used to assess factors influencing the decision to treat. In total, 366 physicians (56 women, 308 men, 2 undisclosed) from 44 countries provided 3294 responses to 9 scenarios. Most (54.1%, 1782/3294) were in favor of endovascular treatment. Participants were more likely to treat occlusions in the anterior M2/3 (74.3%; risk ratio = 2.62; 95% CI, 2.27-3.03) or A3 (59.7%; risk ratio = 2.11; 95% CI, 1.83-2.42) segment compared with the M3/4 segment (28.3%; reference). Physicians were less likely to pursue endovascular treatment in patients who showed neurologic improvement than in patients with an unchanged neurologic deficit (49.9% versus 57.0% responses in favor of endovascular treatment, respectively; risk ratio = 0.88, 95% CI, 0.83-0.92). Interventionalists and more experienced physicians were more likely to treat secondary medium vessel occlusions. Physicians' willingness to treat secondary medium vessel occlusions endovascularly is limited and varies per occlusion location and change in neurologic status. More evidence on the safety and efficacy of endovascular treatment for secondary medium vessel occlusion stroke is needed.

Midterm Outcomes of a Prospective, Nonrandomized Study to Evaluate Endovascular Repair of Complex Aortic Aneurysms Using Fenestrated-Branched Endografts.

The aim of this study was to investigate the midterm outcomes of fenestrated and branched endovascular aortic repair (FB-EVAR) of pararenal (PRA) and thoracoabdominal aortic aneurysms (TAAAs). FB-EVAR has been associated with decreased morbidity compared to open repair, but there is limited midterm data. A total of 430 patients (302 males, mean age 74 ± 8 years) treated by FB-EVAR were enrolled in a prospective, nonrandomized investigational device exemption study. Endpoints included 30-day mortality and major adverse events (MAEs), freedom from all cause and aortic-related mortality, target vessel patency, and freedom from secondary intervention and target vessel instability. There were 133 PRAs and 297 TAAAs with 1673 renal-mesenteric arteries incorporated by fenestrations or directional branches (3.9 ± 0.5 vessels/patient). At 30 days or within the hospital stay if longer than 30 days, there were 4 (0.9%) deaths. MAEs included new-onset dialysis in 8 patients (2%), permanent paraplegia or stroke in 10 patients each (2%), and respiratory failure requiring tracheostomy in 2 patients (0.5%). After a mean follow-up of 26 ± 20 months, there were 3 (0.7%) aortic-related deaths from SMA stent occlusion, gastrointestinal hemorrhage, or complications of open arch repair. At 5 years, freedom from all-cause and aortic-related mortality were 57% ± 5% and 98% ± 1%, respectively. Freedom from secondary intervention was 64% ± 4%, primary target vessel patency was 94% ± 1%, and freedom from target vessel instability was 89% ± 2% at same interval. One patient (0.2%) had nonfatal aneurysm treated using endovascular repair. FB-EVAR is safe and effective for treatment of PRA and TAAAs with low rate of aortic-related mortality and aneurysm rupture on midterm follow-up.

Numerical modelling of the effects of vessel length-to-diameter ratio (L/D) on pressure piling

Pressure piling presents a major explosion hazard in interconnected process vessels. Pressure enhancement in the secondary vessel due to the acceleration of the flame through the connecting pipe can generate a disproportionately more violent explosion than would have been expected based on the concentration of dust in the secondary vessel. Pressure piling is a very complex phenomenon that is difficult to investigate through experimentation. Advanced computational fluid dynamics (CFD) modelling is a promising route to accurately account for all the complexities associated with pressure piling.In this paper, the current state of knowledge concerning pressure piling is presented. Further, the effects of varying the length-to-diameter ratio (L/D) of the primary vessel (Vessel 1) on pressure piling was investigated using numerical modelling. The volumes and volume ratio of the interconnected vessels were kept constant while the L/D of Vessel 1 was varied from 0.5 to 15. The simulations of coal dust explosion were performed using the coalChemistryFoam solver from OpenFOAM version 5.0.1. It is hoped that the findings from this study provide insight into the effects of the geometrical design of interconnected vessels, particularly L/D, on pressure piling. Additionally, this work has implications for the optimal placement of explosion isolation devices intended to actuate before the flame front and pressure escape to downstream vessels.

Effectiveness of very low profile thrombectomy device in primary distal medium vessel occlusion, as rescue therapy after incomplete proximal recanalization or following iatrogenic thromboembolic events

BackgroundRecent progress with smaller retrievers has expanded the ability to reach distal brain arteries. We herein report recanalization, bleeding complications and short-term clinical outcomes with the smallest currently known low...

Three-dimensional Imaging Coupled with Topological Quantification Uncovers Retinal Vascular Plexuses Undergoing Obliteration.

Introduction: Murine models provide microvascular insights into the 3-D network disarray seen in retinopathy and cardiovascular diseases. Light-sheet fluorescence microscopy (LSFM) has emerged to capture retinal vasculature in 3-D, allowing for assessment of the progression of retinopathy and the potential to screen new therapeutic targets in mice. We hereby coupled LSFM, also known as selective plane illumination microscopy, with topological quantification, to characterize the retinal vascular plexuses undergoing preferential obliteration.Method and Result: In postnatal mice, we revealed the 3-D retinal microvascular network in which the vertical sprouts bridge the primary (inner) and secondary (outer) plexuses, whereas, in an oxygen-induced retinopathy (OIR) mouse model, we demonstrated preferential obliteration of the secondary plexus and bridging vessels with a relatively unscathed primary plexus. Using clustering coefficients and Euler numbers, we computed the local versus global vascular connectivity. While local connectivity was preserved (p > 0.05, n = 5 vs. normoxia), the global vascular connectivity in hyperoxia-exposed retinas was significantly reduced (p < 0.05, n = 5 vs. normoxia). Applying principal component analysis (PCA) for auto-segmentation of the vertical sprouts, we corroborated the obliteration of the vertical sprouts bridging the secondary plexuses, as evidenced by impaired vascular branching and connectivity, and reduction in vessel volumes and lengths (p < 0.05, n = 5 vs. normoxia).Conclusion: Coupling 3-D LSFM with topological quantification uncovered the retinal vasculature undergoing hyperoxia-induced obliteration from the secondary (outer) plexus to the vertical sprouts. The use of clustering coefficients, Euler's number, and PCA provided new network insights into OIR-associated vascular obliteration, with translational significance for investigating therapeutic interventions to prevent visual impairment.

Beyond Giant Cell Arteritis and Takayasu's Arteritis: Secondary Large Vessel Vasculitis and Vasculitis Mimickers.

To provide an overview of mimickers of large vessel vasculitis (LVV), by the main presenting manifestation, i.e., systemic, vascular, and cranial manifestations. The main differential diagnoses in patients with giant cell arteritis (GCA) and Takayasu arteritis (TAK) presenting with systemic manifestations (i.e., fever, anorexia, weight loss, night sweats, arthralgia/myalgia, and/or increased inflammatory indexes) are neoplastic, infectious, or other inflammatory conditions. In patients with vascular manifestations (such as peripheral ischemia, vascular stenoses, or aneurysms), atherosclerosis and non-inflammatory vascular diseases should be excluded. In those presenting with predominant cranial symptoms (i.e., temporal headache, jaw claudication, scalp tenderness, transient or permanent vision loss), other causes of headache, cerebrovascular accidents, optic neuropathy, and neuromuscular syndromes need to be considered. The diagnosis of LVV maybe challenging, especially when patients present with atypical or incomplete clinical forms. In these cases, a multidisciplinary approach is strongly recommended.

Antitumor activity of Moringa oleifera (drumstick tree) flower trypsin inhibitor (MoFTI) in sarcoma 180-bearing mice

The plant Moringa oleifera is used as food and medicine. M. oleifera flowers are source of protein, fiber, and antioxidants, and are used to treat inflammation and tumors. This work evaluated the antitumor activity of the M. oleifera flower trypsin inhibitor (MoFTI) in sarcoma 180-bearing mice. Swiss female mice were inoculated with sarcoma 180 cells. Seven days later, the animals were treated intraperitoneally for 1 week with daily doses of PBS (control) or MoFTI (15 or 30 mg/kg). For toxicity assessment, water and food consumption, body and organ weights, histological alterations, and blood hematological and biochemical parameters were measured. Treatment with MoFTI caused pronounced reduction (90.1%–97.9%) in tumor weight. The tumors of treated animals had a reduced number of secondary vessels and lower gauge of the primary vessels compared to the control. No significant changes were observed in water and food consumption or in body and organ weights. Histopathological analysis did not indicate damage to the liver, kidneys, and spleen. In conclusion, MoFTI showed antitumor potential, with no clear evidence of toxicity.

New Insights into the Pathophysiology of Primary and Secondary Lymphedema: Histopathological Studies on Human Lymphatic Collecting Vessels.

Background: Lymphedema is characterized by an accumulation of interstitial fluids due to inefficient lymphatic drainage. Primary lymphedema is a rare condition, including congenital and idiopathic forms. Secondary lymphedema is a common complication of lymph node ablation in cancer treatment. Previous studies on secondary lymphedema lymphatic vessels have shown that after an initial phase of ectasia, worsening of the disease is associated with wall thickening accompanied by a progressive loss of the endothelial marker podoplanin. Methods and Results: We enrolled 17 patients with primary and 29 patients with secondary lymphedema who underwent lymphaticovenous anastomoses surgery. Histological sections were stained with Masson's trichrome, and immunohistochemistry was performed with antibodies to podoplanin, smooth muscle α-actin (α-SMA), and myosin heavy chain 11 (MyH11). In secondary lymphedema, we found ectasis, contraction, and sclerosis vessel types. In primary lymphedema, the majority of vessels were of the sclerosis type, with no contraction vessels. In both primary and secondary lymphedema, not all α-SMA-positive cells were also positive for MyH11, suggesting transformation into myofibroblasts. The endothelial marker podoplanin had a variable expression unrelatedly with the morphological vessel type. Conclusions: Secondary lymphedema collecting vessels included all the three types described in literature, that is, ectasis, contraction, and sclerosis, whereas in primary lymphedema, we found the ectasis and the sclerosis but not the contraction type. Some cells in the media stained positively for α-SMA but not for MyH11. These cells, possibly myofibroblasts, may contribute to collagen deposition.

Consequence prediction for dust explosions involving interconnected vessels using computational fluid dynamics modeling

Combustible dust explosions continue to present a significant threat toward operating personnel and pneumatic conveyance equipment in a wide variety of processing industries. Following ignition of suspended fuel within a primary enclosure volume, propagation of flame and pressure fronts toward upstream or downstream interconnected enclosures can result in devastating secondary explosions if not impeded through an appropriate isolation mechanism. In such occurrences, an accelerated flame front may result in flame jet ignition within the secondary vessel, greatly increasing the overall explosion severity. Unlike an isolated deflagration event with quantifiable reduced pressures (vent sizing according to NFPA 68 guidance), oscillation of pressure between primary and secondary process vessels leads to uncertain overpressure effects. Dependent on details of the application such as relative enclosure volumes, relief area, fuel type, suspended concentration, duct size, and duct length, the maximum system pressure in both interconnected vessels can be unpredictable. This study proposes the use of FLame ACceleration Simulator (FLACS) computational fluid dynamics (CFD) modeling to provide reliable consequence predictions for specific case scenarios of dust deflagrations involving interconnected equipment. Required minimum supplement to the originally calculated relief area (Av) was determined through iterative simulation, allowing for reduced explosion pressures (Pred) to be maintained below theoretical enclosure design strengths (Pes).

Tiba Induced Morphological and Root Anatomical Changes in Lentil

A field experiment was conducted to evaluate the effect of 2,3,5-triiodobenzoic acid (TIBA) at 0, 10, 20, 30 and 40 ppm on the morphological and root anatomical changes of lentil (Lens culinaris Medik. cv. BARI Mosur-7). Foliarly applied TIBA decreased plant height significantly with the increasing concentrations of TIBA. Significantly maximum number of branches and leaves per plant were recorded due to 10 ppm TIBA treatment. Leaves were darker green in plants receiving 10 ppm TIBA due to high chl-a, -b and low carotenoid contents compared to control. Ten ppm TIBA increased root length significantly and root diameter non-significantly than the control plants. Root diameter in plants treated with 10 ppm TIBA increased due to the increase in the width of the cortex, decrease in vessel diameter and enhancement of the formation of more secondary xylem vessels.&#x0D; Journal of Bangladesh Academy of Sciences, Vol. 43, No. 2, 107-112, 2019

Effects of Urtica cannabina to Leymus chinensis Ratios on Ruminal Microorganisms and Fiber Degradation In Vitro.

Simple SummaryUrtica cannabina is an unconventional forage crop that has a wide distribution in northern parts of China and is rich in nutritional values. It has a considerable practical significance in cases of shortage of quality forage, such as Leymus chinensis, which is used for the growth and production of ruminants. Our study found that proper addition ratios of U. cannabina and L. chinensis can increase the fiber digestibility by modulating the rumen microbial community in vitro. We also suggest that proper addition of U. cannabina and L. chinensis ratios may be one of the nutritional strategies that can improve the digestion and absorption performance of fiber feedstuff and potentially alleviate the shortage of quality forage for ruminants.The study was conducted in vitro to investigate the effects of different ratios of Urtica cannabina and Leymus chinensis on fiber microstructure and digestibility in ruminal fluid. The experiment was divided into five groups based on the U. cannabina/L. chinensis ratios: A (0:100), B (30:70), C (50:50), D (70:30), and E (100:0). The culture medium was collected at 0, 1, 3, 6, 12, and 24 h. The results showed that: (1) in vitro crude protein degradability (IVCPD) was higher in group A, whereas in vitro neutral detergent fiber degradability (IVNDFD) was higher in group C (p < 0.05); (2) protozoa count was increased from 1 h to 3 h and decreased afterwards, with significant differences observed in several genera (p < 0.05); (3) microbial crude protein (MCP) contents at 1, 3, 6, and 24 h were higher in groups A and C (p < 0.05); (4) the basic tissue of U. cannabina was gradually degraded. At 24h, the secondary xylem vessel structure was observed in groups B and C, but not in groups D and E. In summary, there was higher neutral detergent fiber (NDF) digestibility, higher rumen MCP contents, and lower protozoa count, showing the significance of the 50:50 ratio for microbial growth and fiber digestibility.

Outcomes of target vessel endoleaks after fenestrated-branched endovascular aortic repair

ObjectiveThe objective of this study was to determine the incidence rate, outcomes, and risk factors of target vessel-related endoleaks after fenestrated-branched endovascular aortic repair (F-BEVAR) for pararenal aneurysms or thoracoabdominal aortic aneurysms (TAAAs). MethodsWe reviewed consecutive patients treated by F-BEVAR between 2007 and 2017. Target vessel endoleaks were identified by computed tomography angiography (CTA). Follow-up included CTA and duplex ultrasound before discharge, at 2 months, at 6 months, and annually thereafter. Primary endoleaks were detected by predismissal CTA; secondary endoleaks were absent on the first CTA and were identified during follow-up. End points were spontaneous resolution of primary endoleaks, secondary interventions, and aneurysm rupture. Multivariable analyses were performed for risk factors of target vessel endoleaks and predictors of spontaneous resolution. ResultsA total of 382 patients (mean age, 75 ± 8 years; 75% male) underwent F-BEVAR for 195 pararenal aneurysms and 187 TAAAs with 1204 renal-mesenteric arteries targeted by 981 fenestrations and 223 directional branches. Fifty-two target vessel endoleaks were identified in 41 patients; 41 were type IIIC (interattachment), 10 were type IC (distal bridging stent sealing zone), and 1 was type IIIB (bridging stent fabric tear). Thirty-three patients (9%) had primary target vessel endoleaks in 41 target vessels (3%). Eight patients (2%) developed 11 secondary target vessel endoleaks. Directional branches were more prone to primary endoleaks (13/223 [6%]) in comparison to fenestrations (28/981 [3%]; P = .03). However, branch endoleaks resolved more often spontaneously (11/14 [79%]) compared with fenestration endoleaks (14/38 [37%]; P = .008). Other risk factors for target vessel endoleaks included inner aortic diameter ≥30 mm at the target vessel origin, four or more targeted vessels, TAAA (for primary endoleaks), and physician-modified endograft (for secondary endoleaks). Four patients with primary endoleaks underwent successful reintervention before discharge, and 29 were observed with a mean follow-up of 24 ± 21 months. Of the 41 primary endoleaks, 25 resolved spontaneously in 20 patients (61%) at first follow-up with no recurrences. Of the observed endoleaks, 11 persisted in 9 patients, and 8 of those endoleaks were treated in 7 patients. All secondary target vessel endoleaks required reintervention. There was one possible aneurysm rupture attributed to persistent secondary target vessel endoleak. ConclusionsTarget vessel endoleak on CTA at discharge occurs in 1 of 10 patients treated by F-BEVAR. Of these, two-thirds resolve spontaneously, especially those affecting directional branches. Among patients with a persistent endoleak, endovascular reintervention is usually successful and aneurysm rupture is rare.

Classification of Factors Associated with Stenosis, Re-Occlusion and Subsequent Re-intervention, Following Deep Venous Stenting for Acute Iliofemoral Deep Venous Thrombosis

Introduction: Post thrombotic syndrome (PTS) is devastating sequela of acute iliofemoral deep venous thrombosis (DVT). Thrombolysis and deep venous stenting aims to restore vessel outflow and reduce PTS in accordance with the open vessel hypothesis. For a proportion of patients, despite initial interventional success, re-occlusion or stenosis will necessitate further treatment. This study aimed to determine and classify the causes of re-occlusion and stenosis following deep venous interventions for acute iliofemoral DVT, with identification of preventable factors to improve future treatment. Methods: A retrospective single centre cohort study of patients successfully lysed for treatment of iliofemoral DVT between November 2013 and 2017 was carried out. Patient records and imaging were examined for: baseline demographics, risk factors, extent of DVT, extent of vessel clearance, stents inserted, quality of in-flow, time to and success of re-intervention, anticoagulation compliance, and secondary vessel patency. Failure was classified as either technical, haematological, flow related or mixed. Technical causes were further subdivided into lack of stenting, failure to address inflow or outflow and device related failure. Results: 143 limbs were identified: 95 without further intervention (66%), and 48 limbs (34%) requiring re-intervention. 45% of cases occurred in the first 6 weeks, with a median time to re-intervention of 45 days. Re-intervention was successful in 31 cases (67%). This was achieved in all cases managed prior to complete vessel occlusion compared to 8/25 (32%) of those presenting with complete occlusion (p=0.001). Need for re-intervention was associated with a younger median age (44 vs. 31, p=0.002), IVC involvement (13% vs. 35%, p=0.002) and presence of a stent across the inguinal ligament (15% vs. 38%, p=0.002). Non-compliance with anticoagulation post-procedurally was found to be strongly associated with re-occlusion: relative risk 3.17 (95%CI 0.29-0.91, p=0.0001). Haematological issues were observed in 33% of re-intervention cases, flow-related issues in 44%% of re-intervention cases, and technical problems were observed in 54% of re-intervention cases. Four cases due to stent fracture or compression were observed. Identified problems were multifactorial in 27% of cases. Overall vessel salvage was achieved in 71% of cases with a single causative factor compared to 54% of cases classified as multifactorial. This did not translate into a statistically significant difference in secondary patency. Conclusion: Re-intervention occurred due to potentially preventable factors in a substantial proportion of patients. Re-intervention following complete vessel re-occlusion carries a lower likelihood of success. This study emphasises the need for precision in stenting technique, for post-procedural surveillance, and for adherence to anticoagulation in order to optimise patient outcome. Disclosure: Cook, BSCI, Optimed, Bard, Medtronic, Vesper, Veniti, Philips-Volcano, BTG

Decrease in Secondary Neck Vessels in Multiple Sclerosis: A 5-year Longitudinal Magnetic Resonance Angiography Study.

Studies have previously shown greater arterial and venous extracranial vascular changes in persons with multiple sclerosis (PwMS) when compared to healthy controls (HCs). To determine the change in the number and size of secondary neck vessels in PwMS and HCs over a 5-year follow-up period. Both at baseline and follow-up, 83 PwMS and 25 HCs underwent magnetic resonance angiography (MRA) imaging and analysis. The number and cross-sectional area (CSA) of all secondary neck vessels (excluding the common/internal carotid, vertebral artery, and internal jugular vein) measured at levels from C2-T1 were determined by semi-automated edge detection/ contouring software. The longitudinal change in the number and CSA of the secondary neck vessels from the PwMS and HCs were analyzed by non-parametric Wilcoxon repeated measure. Benjamini-Hochberg procedure adjusted for false discovery rate (FDR). For over 5 years, PwMS demonstrated a consistent longitudinal decrease in both the number of secondary neck vessels (Z-change between -3.3 and -5.4, q=0.001) and their CSA (Zchange between -2.9 and -5.2, q=0.004). On the contrary, the HCs did not demonstrate a significant longitudinal change in secondary neck vessels over the follow-up period. Due to the longitudinal decrease, the PwMS showed a lower number of secondary neck vessels when compared to HCs measured at follow-up (p<0.029, except for C4 with trending p=0.071). The PwMS changes were also corroborated within each MS phenotype. PwMS demonstrate a significant mid-term decrease in the number and the size of the secondary neck vessels. The clinical relevance of these findings and the effect on intracranial blood flow are currently unknown.

Impact of secondary interventions on mortality after fenestrated branched endovascular aortic aneurysm repair

BackgroundFenestrated and branched endovascular aortic repair (F/BEVAR) is increasingly used to manage pararenal and thoracoabdominal aortic disease (TAAA). Device-related reintervention after F/BEVAR is common, but little is known about its impact on postoperative mortality. The purpose of this analysis was to describe secondary intervention (SI) after F/BEVAR and determine the impact of these procedures on patient survival. MethodsA single-center review was done on all consecutive F/BEVARs performed from 2010 to 2016. Primary end points were incidence of secondary aortic, branch, and/or access vessel‒related SI, and survival. SI was categorized as minor endovascular (branch restenting, access vessel treatment, or percutaneous coil embolization), major endovascular (new aortic graft placement), or open (bleeding, access vessel, and/or aortic). Kaplan-Meier methodology was used to estimate freedom from SI and survival. Multivariable analysis was used to identify predictors of SI. ResultsA total of 308 F/BEVAR procedures were performed (75% physician-modified, 18% custom, 7% Zfen), with 1022 vessels revascularized (celiac, 228; superior mesenteric artery [SMA], 263; renal, 525). There were 117 (39%) extent I-III TAAA, 132 (44%) extent IV TAAA/4-vessel pararenal, and 54 (18%) <4-vessel pararenal repairs performed. Any type of SI occurred in 24% (74) of patients during the mean follow-up of 20 ± 21 months. The majority of reinterventions were endovascular (minor, 53% [n = 39]; major, 32% [n = 24]), whereas 12% (n = 9) were open and 3% (n = 2) hybrid. Primary indication for SI included: 22 (29%) with branch-related endoleaks (1C or III); 15 (22%) with proximal or distal aortic degeneration; 8 (12%) with branch vessel thrombosis/stenosis; 10 (11%) with aortic device type III endoleak/loss of overlap; 4 (6%) with postoperative mesenteric or renal bleeding events; 5 (5%) with type II endoleak; 3 (5%) with access vessel complication; and 2 (3%) with graft infection. Most SIs were elective (65%; n = 48) with the remainder occurring emergently (24%; n = 18) or for symptoms/urgently (11%; n = 8). Compared with endovascular remediation, open SI was more likely to be emergent (89%, 8 of 9; P = .001). Freedom from SI was 80 ± 3% and 64 ± 4% at 1 and 3 years, respectively. One- and 5-year survival with or without SI was: 1 year, 88 ± 4% vs 81 ± 3%; 5 years, 76 ± 5% vs 59 ± 4% (log rank test, P = .06). There was no survival difference based on type of SI (log rank test, P = .3). Extent I-III TAAA (HR, 1.6; 95% CI, 0.98-3.3; P = .06) and history of cerebrovascular disease (HR, 1.8; 95% CI, 0.97-2.6; P = .07) were predictive of SI. ConclusionsSIs after F/BEVAR most frequently involve branch vessel or aortic device remediation procedures; however, they do not negatively impact out-of-hospital survival. These results further highlight the crucial role of imaging surveillance after F/BEVAR to maintain durability. Discussions with patients, periprocedural planning, and the next generation of device design must focus on issues surrounding the risk of device-related SI events.

Decrease in size of secondary neck vessels and cerebral aqueduct enlargement in multiple sclerosis: a 5-year longitudinal MRI study

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