Complete Vessel Research Articles

Development of pre-seeded tissue-engineered vascular grafts in vitro

Current vascular surgery employs reconstruction of occluded blood vessels using autologous grafts. As a considerable proportion of patients lack healthy autologous vessels to be used as the grafts, the development of tissue-engineered, small-diameter vascular grafts has significant clinical relevance. Biodegradable vascular grafts, which have a defined degradation rate upon the implantation, provide an opportunity for the controlled vascular regeneration. Such polymer framework acts as a guiding matrix for organising the patient's newly formed tissues to ensure consistent and complete vessel remodeling. The crucial aspect of tissue-engineered vascular graft regeneration is endothelialisation, as non-endothelialised blood vessels suffer from the thrombosis if having < 5 mm diameter because of low blood flow. This review describes two approaches to stimulate endothelialization. The first is the biofunctionalization of the luminal surface with the bioactive peptides with the following in situ implantation. Using the body as a bioreactor, this approach relies on the selective recruitment of endothelial cells. The second approach includes in vitro pre-seeding of a luminal surface with an endothelial cell monolayer. The development of such pre-seeded vascular grafts requires the choice of an appropriate polymer for the manufacture of a 3D matrix, isolation of endothelial cell culture, and tuning of mechanical stimuli to control the cell specification during the pre-seeding. In addition to the pre-seeding of endothelial cells on the luminal surface, it is necessary to adapt them to the flow to prevent shedding or incorrect orientation. Cell adhesion can be enhanced by the attachment of extracellular matrix proteins to the luminal surface or by mimicking natural blood flow conditions. Sustained mechanical stimuli facilitate the adaptation of endothelial cells to the flow and contribute to the maturation of endothelial progenitor cells.

Preemptive fenestrated endovascular repair aimed at perfusion of cervical branches in acute type B aortic dissection.

Most of the entry tears of uncomplicated type B aortic dissection are located in the distal arch and extends in a retrograde manner to the level of the left subclavian artery. Our objective was to evaluate feasibility and effectiveness using fenestrated sent graft with complete neck vessel preservation to treat uncomplicated type B aortic dissection. We retrospectively reviewed the record of patients with uncomplicated type B aortic dissection who underwent fenestrated thoracic endovascular aortic repair in subacute phase (15-90days) between August 2016 and April 2020. The Najuta fenestrated stent graft was placed proximally beyond he left subclavian artery (zone 0-2) in an attempt to seal the entry while preserving the neck vessels. We evaluated 9 cases (male: 7, female: 2; median age 70years). The median distance from the LSA to the proximal entry was 37mm. The landing zones of the proximal end of the Najuta were zone 0: 3, zone 1: 2, and zone 2: 4 cases. Technical success was 100% with no 30-day death. None of the patients had a stroke, paraplegia or retrograde dissection, and no endoleak was observed. Complete aortic remodeling with false lumen resolution was obtained in all cases while each fenestrated vessels remained patent during the follow-up period. Preemptive thoracic endovascular aortic repair aimed at perfusion of cervical branches using the Najuta fenestrated stent is safe and effective and may be considered as a reasonable treatment option for the treatment is a safe and an effective treatment.

Vessel wall imaging features of Moyamoya disease in a North American population: patterns of negative remodelling, contrast enhancement, wall thickening, and stenosis

BackgroundThis study characterized vessel wall imaging (VWI) features of Moyamoya disease (MMD) in a predominantly adult population at a North American center.MethodsConsecutive patients with VWI were included. Twelve arterial segments were analyzed for wall thickening, degree and pattern of contrast enhancement, and remodeling.ResultsOverall, 286 segments were evaluated in 24 patients (mean age = 36.0 years [range = 1–58]). Of 172 affected segments, 163 (95%) demonstrated negative remodeling. Complete vessel wall obliteration was most frequent in the proximal M1 (17/48, 35%). Affected segments enhanced in 72/172 (42%) (n = 15 for grade II; n = 54 for concentric and n = 18 for eccentric); 20 of 24 (83%) patients had at least one enhancing segment. Both enhancing and non-enhancing segments were present in 19/20 (95%) patients. Vessel wall enhancement was most common in the proximal segments and correlated to the degree of stenosis (p < 0.001), and outer wall diameter (p < 0.001), but not disease duration (p = 0.922) or Suzuki score (p = 0.477). Wall thickening was present in 82/172 (48%) affected segments and was associated with contrast enhancement (p < 0.001), degree of stenosis (p < 0.001), and smaller outer wall diameter (p = 0.004).ConclusionThis study presents VWI findings in North American patients with MMD. Negative remodeling was the most common finding. Most patients had both enhancing and non-enhancing abnormal segments. Vessel wall enhancement was most common in proximal segments, variable in pattern or degree and was correlated to the degree of stenosis and smaller outer wall diameter.

Using 3D Microscope for Hepatic Artery Reconstruction in Living Donor Liver Transplant.

Introduction: This study compares the intraoperative process of hepatic artery anastomosis using conventional microscope and novel 3D digital microscope and discusses our technique and operative set-up. Method: A retrospective comparative cohort study with 46 hepatic artery reconstructions in living donor liver transplant patients. Either an operational microscope (control group) or a 3D digital microscope Mitaka Kestrel View II (study group) was used for hepatic artery anastomosis. We then discuss and share our institution’s experience of improving surgical training. Results: Both operation instruments provide effective and comparable results. There was no statistical difference regarding operational objective results between conventional microscope and exoscope. Both instruments have no hepatic artery size limit, and both resulted in complete vessel patency rate. Conclusions: There was no statistical differences regarding hepatic artery anastomosis between microscope and exoscope cohorts. Microsurgeons should perform hepatic artery anastomosis efficiently with the instruments they are most proficient with. Yet, exoscope provided better ergonomics in the operation room and lessened musculoskeletal strain, allowing surgeons to work in a more neutral and comfortable posture while allowing the first assistant to learn and assist more effectively. Using exoscope with micro-forceps and modified tie technique make artery reconstruction easier.

Automatic Method for Blood Vessel Diameter Measurement on Color Retinal Images

Automatic detection of retinal blood vessels and measurement of blood vessel diameter has become very useful in medical applications, including the diagnosis and monitoring of vascular therapy. This paper present a new method for the detection of retinal blood vessels from fundus images. In addition, it accurately determines the blood vessels diameter. The proposed system consists of several stages starting from the detection of a complete blood vessel network (retinal images), a segmentation process, an extraction of blood vessel centerlines, and a new approach for the measurement of the blood vessel diameters utilizing the circle diameter approach. The application of the proposed method is based on three publicly available databases (DRIVE, STARE, CHASE_DB and HRF), which has been conducted and compared to recently reported measurement techniques. Numerical results demonstrate the efficacy of the proposed method achieving a success rate of 100% with 2.2454×10−4 as mean and 4.5833×10−5 as standard deviation differences. This could be harnessed in the future blood vessel measurement techniques.

DIGITAL ENTERPRISE PLATFORM - ENABLING EFFICIENT CAD, PLM, ERP INTEGRATION ON SHIPYARDS

The design and production of vessels is nowadays supported by a plethora of IT tools. This comprises both tools which are very specific to shipbuilding, like hydrostatic and -dynamic design tools, as well as generic tools, like generic CAD or ERP systems, used also by other industries. Most of these tools started as island solutions, resulting in difficulties to manage the complete vessel design or even all shipyard processes as a holistic approach. Such a holistic approach allows data reuse wherever needed, without manual transfer causing additional effort and potential errors. This paper presents several use-cases for such an approach, which are beneficial for shipyards. Some of them are driven by step-by-step improvements of a shipyard’s operation, whereas others are needed to capitalize on the benefits of a merger of two shipyards.

Life cycle assessment of alternative marine fuels for super yacht

Despite its relatively small size, the global super yacht fleet has considerable environmental impact. The emissions of these vessels, in concert with the wider maritime industry are under increasing scrutiny and pressure to achieve reductions. Ambitious policy targeting reductions in greenhouse gas (GHG), NOx and SOx emissions will require significant changes in vessel propulsion and fuel use. This paper examines the environmental impact of various alternative low-emission fuels for a super yacht. The study investigated well-to-wake energy consumption and the environmental impact of alternative low-emission fuels over the complete vessel lifetime. A comparative Life Cycle Assessment was performed on Marine Gas Oil (MGO), Liquefied Natural Gas (LNG), methanol, biodiesel and hydrogen with various energy production pathways. Results suggested that hydrogen produced using a wind energy pathway offers the most environmentally sound alternative to MGO; with a 93.95% reduction in GHG emissions and 91.95% acidification potential (AP) emissions. Fossil based alternatives have very limited potential to achieve regulatory reduction targets. Global warming potential (GWP) suggest that LNG fuel can reduce 20% to 25% CO2 emission in the Tank-to-Wake phase in comparison with MGO. However, considering CH4 emissions, may result in a 5.4% higher GWP. The results highlight the differences in lifecycle emissions as a result of different production pathways. The paper concludes with recommendations for hydrogen from a renewable production.

Abstract No. 292 Balloon embolization devices deliver more rapid, complete, and lasting artery occlusion

Peripheral artery embolization procedures are performed for a variety of clinical indications including stopping life-threatening bleeding, reducing blood flow to cancerous tumors, and diverting blood away from arterial aneurysms, arteriovenous fistulas, and other vascular malformations. Typically, these procedures involve the implantation of coils or porous vascular plugs to slow blood flow and stimulate the formation of thrombus to achieve complete blood vessel occlusion. These devices often require substantial time to achieve complete occlusion, and can be susceptible to vessel recanalization, all of which can reduce the overall effectiveness of the treatment.

Recursive Centerline- and Direction-Aware Joint Learning Network with Ensemble Strategy for Vessel Segmentation in X-ray Angiography Images

Background and objectiveAutomatic vessel segmentation from X-ray angiography images is an important research topic for the diagnosis and treatment of cardiovascular disease. The main challenge is how to extract continuous and completed vessel structures from XRA images with poor quality and high complexity. Most existing methods predominantly focus on pixel-wise segmentation and overlook the geometric features, resulting in breaking and absence in segmentation results. To improve the completeness and accuracy of vessel segmentation, we propose a recursive joint learning network embedded with geometric features. MethodsThe network joins the centerline- and direction-aware auxiliary tasks with the primary task of segmentation, which guides the network to explore the geometric features of vessel connectivity. Moreover, the recursive learning strategy is designed by passing the previous segmentation result into the same network iteratively to improve segmentation. To further enhance connectivity, we present a complementary-task ensemble strategy by fusing the outputs of the three tasks for the final segmentation result with majority voting. ResultsTo validate the effectiveness of our method, we conduct qualitative and quantitative experiments on the XRA images of the coronary artery and aorta including aortic arch, thoracic aorta, and abdominal aorta. Our method achieves F1 scores of 85.61±3.48% for the coronary artery, 89.02±2.89% for the aortic arch, 88.22±3.33% for the thoracic aorta, and 83.12±4.61% for the abdominal aorta. ConclusionsCompared with six state-of-the-art methods, our method shows the most complete and accurate vessel segmentation results.

Risk factors and classification of reintervention following deep venous stenting for acute iliofemoral deep vein thrombosis

BackgroundAcute iliofemoral deep vein thrombosis (DVT) is associated with the development of post-thrombotic syndrome (PTS). Thrombolysis and deep venous stenting can restore vessel outflow and can reduce the incidence of PTS. However, for a proportion of patients, subsequent stenosis or reocclusion will necessitate further intervention. In the present study, we aimed to identify the risk factors, examine the outcomes (reintervention success and PTS), and develop a classification system for reintervention. MethodsA retrospective single-center cohort study of patients who had undergone successful lysis for iliofemoral DVT from 2013 to 2017. The patients’ records and imaging studies were examined for demographics, risk factors, extent of thrombus and vessel clearance, stenting, flow, reintervention, anticoagulation compliance, Villalta score, and secondary patency. From our findings, a system of classification for patients for whom procedures have failed was developed, constituting technical, hematologic, flow related, or multiple factors. ResultsOf 143 limbs (133 patients), 48 (33.6%) had required reintervention, of which 25 had presented with reocclusion (17.4%). The median time to reintervention was 45 days. The need for reintervention was associated with inferior vena cava thrombus (risk ratio [RR], 2.16; P < .01), stenting across the inguinal ligament (RR, 2.08; P < .01), and anticoagulation noncompliance (RR, 7.09; P < .01). Successful reintervention was achieved in 31 limbs (64.6%): 23 of 23 (100%) treated before occlusion vs 8 of 25 (36.4%) treated after occlusion (RR, 32.31; P < .01). A greater incidence of any PTS was observed for patients requiring reintervention (median Villalta score, 3 [interquartile range, 1-5]; vs 1 [interquartile range, 1-4]; RR, 2.28; P = .029). Cases without complete vessel occlusion (reintervention and control) had a lower rate of any PTS (14.0% vs 42.9%; RR, 3.06; P < .01) and moderate to severe PTS (3.0% vs 14.3%; RR, 4.76; P = .046) Technical issues were observed in 54.2% of reintervention cases and 6.3% of cases not requiring reintervention (P < .01). Hematologic issues were identified in 33.3% of reintervention cases and 1.1% of cases not requiring reintervention (P < .01). Flow-related issues were observed in 43.8% of the reintervention cases and no cases not requiring reintervention (P < .01). Of the reintervention cases, 27.1% were multifactorial and were associated with a lower rate of vessel salvage; however, this did not translate into a significant difference in secondary patency on survival analysis (RR, 1.70; P = .429). ConclusionsA large proportion of patients required reintervention because of potentially preventable factors. Anticoagulation compliance, thrombus burden, and poor flow are important risk factors to consider in patient selection. Reintervention increased the risk of PTS and was more often successful when achieved before vessel occlusion.

Target Vessel Versus Complete Revascularization in Non-ST Elevation Myocardial Infarction Without Cardiogenic Shock.

IntroductionThe role of complete revascularization (CR) vs target vessel revascularization (TVR) in non-ST-elevation myocardial infarction (NSTEMI) in patients without cardiogenic shock is still not established. In this study, we compared outcomes at one and six months among patients with NSTEMI with multivessel disease (MVD) undergoing CR vs TVR.MethodsIt was a prospective, observational study carried out among 60 NSTEMI patients with MVD (30 undergoing TVR and 30 CR) from October 2018 to November 2019. They were assessed at one and six months for primary and secondary outcomes.ResultsThe mean age of the patients was 56.13 ± 9.23 years and both the groups were well matched with respect to age, gender, risk factors, and comorbidities. In the majority of patients, the target vessel was left anterior descending (LAD) followed by right coronary artery (RCA) and left circumflex (LCX) in both groups. The primary outcomes of death from any cause, non-fatal myocardial infarction, and the need for revascularization of the ischemia-driven vessel showed no significant difference at one and six months follow-up between the CR and TVR groups. However, the secondary outcomes of heart failure hospitalizations and angina episodes were significantly more in the TVR group than CR group at one month (6 vs 1, P=0.044), (8 vs 2, P=0.038) and six months (8 vs 2, P=0.038), (9 vs 2, P=0.02), respectively.ConclusionCR was associated with no difference in death from all-cause or future revascularization but significantly lesser secondary outcomes of heart failure hospitalizations and angina episodes as compared to TVR in NSTEMI without cardiogenic shock.

Intelligent Algorithm-Based Coronary Angiography Characteristics of Acute Non-ST-Segment Elevation Myocardial Infarction Patients with Different Genders.

Objective This study was aimed at comparing the characteristics of coronary angiography based on intelligent algorithm in patients with acute non-ST-segment elevation myocardial infarction (NSTEMI) of different genders. Methods Eighty patients were selected to segment the coronary angiogram using the convolutional neural network (CNN) algorithm, the input layer of the CNN was used to receive the image dataset, and three-dimensional data were input during semantic segmentation to achieve automatic segmentation of the target features. Segmentation results were quantitatively assessed by accuracy (Acc), sensitivity (Se), specificity (Sp), and Dice coefficient (Dice). The characteristics of coronary angiography were compared between the two groups. Results The CNN algorithm had good segmentation effect, complete vessel extraction, and little noise, and Acc, Se, Sp, and Dice were 90.32%, 93.39%, 91.25%, and 89.75%, respectively. The proportion of diabetes mellitus was higher in female patients with NSTEMI (68.8%) than that in male patients (46.3%); the proportion of the left main coronary artery (LM) and left anterior descending artery (LAD) was lower in the female group (7.5%, 41.3%) than that in the male group (13.8%, 81.3%), and the difference between the two groups was statistically significant (P < 0.05). Conclusion The CNN algorithm achieves accurate extraction of vessels from coronary angiographic images, and women with diabetes and hyperlipidemia are more likely to have NSTEMI than men, especially the elderly.

Abstract WMP116: Age-related Dysfunction In Leptomeningeal Collateral Remodeling After Ischemic Stroke

Introduction: The leptomeningeal collaterals (LMCs) are specialized brain surface arterioles that interconnect the major cerebral artery territories. Good outcome following ischemic stroke is highly correlated with high collateral number and function. Unfortunately, with aging and disease, the LMCs demonstrate impaired dilatory capacity, reduced vessel diameter, and even complete vessel loss (rarefaction). The present study examined the chronic remodeling capacity of LMCs following permanent stroke in young and aged mice. Methods: Young and aged C57BL6 mice (5 and 20 months) were subjected to permanent distal middle cerebral artery occlusion (pdMCAO). At 2 weeks or 3 months, LMCs were evaluated for inner diameter and VWF expression (% LMC coverage). We compared the LMCs feeding the occluded MCA territory (LMC ipsi) to the contralateral equivalent vessels (LMC contra). Diameter change is reported as fold change relative to the distal-most arteriole (DMA) associated with each LMC. Results: Young male mice demonstrated increased diameter of LMC ipsi relative to DMA at both 2 weeks (1.36 ± 0.075; n=24 vessels/4 mice, P&lt;0.01) and 3 months after stroke (1.27 ± 0.073, n=19 vessels/2 mice, P&lt;0.01). LMC contra were 0.901 ± 0.064 and 1.01 ± 0.053 for the same time points (n=19 and 10 vessels, P=NS). VWF expression was significantly increased in LMC ipsi at 2 weeks (ipsi 10.9 ± 2.87 vs. contra 2.91 ± 0.82, P&lt;0.05) and neared significance at 3 months (ipsi 6.45 ± 1.54 vs. contra 2.06 ± 0.264, P=0.051). Aged mice demonstrated increased diameter of LMC ipsi relative to DMA at 2 weeks (1.24 ± 0.052, n=25 vessels from 3 mice, P&lt;0.01), but not at 3 months (1.08 ± 0.044, n=14 from 2 mice, P=NS). Notably, the 3 month LMC ipsi vessels demonstrated irregular diameter and characteristics of rarefaction. LMC contra were 0.897 ± 0.032 and 0.967 ± 0.092 for the same time points (n=17 and 8 vessels, P=NS). VWF expression was significantly elevated in LMC ipsi vs. LMC contra at 2 weeks (6.74 ± 1.33 vs. 1.87 ± 0.361, P&lt;0.01), but not at 3 months (2.27 ± 0.387 vs. 1.81 ± 0.398, P=NS). Conclusions: Our data show lasting LMC remodeling in young stroke brain, consisting of increased LMC diameter and expression of VWF. With aging, LMC remodeling is transient and evidence of LMC rarefaction is apparent by 3 months.

Vessel-based hybrid optic disk segmentation applied to mobile phone camera retinal images.

Precise detection of the optic disk (OD) is an important task in the diagnosis of diabetic retinopathy. To manage the massive diabetic population, there is a significant demand for efficient and remote retinal imaging techniques. In this regard, the use of handheld mobile cameras attached to a smartphone is a promising approach. However, smartphone retinal images are often of low quality, compared to those obtained on standard equipment. They also have a narrow field of view and an incomplete/unbalanced vessel structure. Hence, we propose a new, fully automatic hybrid method for OD localization (HLM). It is designed for and verified on mobile camera/smartphone retinal images. The HLM analyzes the vessel structure and finds the OD locations by using the exclusion method when an image has a complete vessel system, and a newly proposed line detection method, otherwise. For OD segmentation, an active contour model followed by the circle fitting approach is integrated into the HLM. The proposed method was tested on three mobile camera datasets and four datasets obtained by standard equipment. For mobile camera datasets, the HLM achieves an average accuracy of 98% for OD localization. The segmentation routine obtains an average precision of 92.64% and an average recall of 82.38%. Testing against the recent state-of-the-art methods on the standard datasets shows comparable performance. The proposed framework for OD localization and segmentation designed for and verified on mobile camera retinal datasets and standard datasets. (EM - "Exclusion Method", LDM - "Line Detection Method", OD - "Optic Disk" and PPV - "Positive Predictive Value").

Prophylactic sac outflow vessel embolization is associated with improved sac regression in patients undergoing endovascular aortic aneurysm repair

ObjectiveType II endoleaks (T2Es), often identified after endovascular aneurysm repair (EVAR), have been associated with late endograft failure and secondary rupture. The number and size of the patent aortic aneurysm sac outflow vessels (ie, the inferior mesenteric, lumbar, and accessory renal arteries) have been implicated as known risk factors for persistent T2Es. Given the technical challenges associated with post-EVAR embolization, prophylactic embolization of aortic aneurysm sac outflow vessels has been advocated to prevent T2Es; however, the evidence available at present is limited. We sought to examine the effects of concomitant prophylactic aortic aneurysm sac outflow vessel embolization in patients undergoing EVAR. MethodsPatients aged ≥18 years included in the Society for Vascular Surgery Vascular Quality Initiative database who had undergone elective EVAR for intact aneurysms between January 2009 and November 2020 were included in the present study. Patients with a history of prior aortic repair and those without available follow-up data were excluded. The patient demographics, operative characteristics, and outcomes were analyzed by group: EVAR alone vs EVAR with prophylactic sac outflow vessel embolization (emboEVAR). The outcomes of interest were the in-hospital postoperative complication rates, incidence of aneurysmal sac regression (≥5 mm) and T2Es, and reintervention rates during follow-up. ResultsA total of 15,060 patients were included. Of these patients, 272 had undergone emboEVAR and 14,788 had undergone EVAR alone. No significant differences were found between the two groups in age, comorbidities, or anatomic characteristics, including the mean maximum preoperative aortic diameter (5.5 vs 5.6 cm; P = .48). emboEVAR was associated with significantly longer procedural times (148 vs 124 minutes; P < .0001), prolonged fluoroscopy times (32 vs 23 minutes; P < .0001), increased contrast use (105 vs 91 mL; P < .0001), without a significant reduction in T2Es at case completion (17.7% vs 16.3%; P = .54). The incidence of postoperative complications (3.7% vs 4.6%; P = .56), index hospitalization reintervention rates (0.7% vs 1.3%; P = .59), length of stay (1.8 vs 2 days; P = .75), and 30-day mortality (0% vs 0%; P = 1.00) were similar between the two groups. At mid-term follow-up (14.6 ± 6.2 months), the emboEVAR group had a significantly greater mean reduction in the maximum aortic diameter (0.69 vs 0.54 cm; P = .006), with a greater proportion experiencing sac regression of ≥5 mm (53.5% vs 48.7%). The reintervention rates were similar between the two groups. On multivariable analysis, prophylactic aortic aneurysm sac outflow vessel embolization (odds ratio, 1.34; 95% confidence interval, 1.04-1.74; P = .024) was a significant independent predictor of sac regression. ConclusionsProphylactic sac outflow vessel embolization can be performed safely for patients with intact aortic aneurysms undergoing elective EVAR without significant associated perioperative morbidity or mortality. emboEVAR was associated with significant sac regression compared with EVAR alone at mid-term follow-up. Although no decrease was found in the incidence of T2Es, this technique shows promise, and future efforts should focus on identifying a subset of aneurysm and outflow branch characteristics that will benefit from concomitant selective vs complete prophylactic sac outflow vessel embolization.

Retinal Vessel Segmentation Algorithm Based on Residual Convolution Neural Network.

Retinal vessels are the only deep micro vessels that can be observed in human body, the accurate identification of which has great significance on the diagnosis of hypertension, diabetes and other diseases. To this end, a retinal vessel segmentation algorithm based on residual convolution neural network is proposed according to the characteristics of the retinal vessels on fundus images. Improved residual attention module and deep supervision module are utilized, in which the low-level and high-level feature graphs are joined to construct the encoder-decoder network structure, and atrous convolution is introduced to the pyramid pooling. The experiments result on the fundus image data set DRIVE and STARE show that this algorithm can obtain complete retinal vessel segmentation as well as connected vessel stems and terminals. The average accuracy on DRIVE and STARE reaches 95.90 and 96.88%, and the average specificity is 98.85 and 97.85%, which shows superior performance compared to other methods. This algorithm is verified feasible and effective for retinal vessel segmentation of fundus images and has the ability to detect more capillaries.

Effect of the Implementation of a Local Care Pathway on the Transient Ischemic Attack Management in Emergency Departments.

Recent studies have demonstrated that urgent care decreases the risk of subsequent stroke after transient ischemic attack (TIA). In response to heterogeneous TIA management observed in our area, we developed a structured pathway, in accordance with current guidelines and adapted to local resources. We aim to assess the effect of local implementation of this care pathway on TIA management in emergency departments (EDs) in the Rhône area (France). EDs of 5 centers that had a minimum of 30 TIA/year in Lyon and Bourgoin-Jallieu participated. The first 30 consecutive patients who had a TIA as main diagnosis admitted to one of these EDs from January 1 to December 31, 2013 and from January 1 to December 31, 2016, that is, before-and-after care pathway implementation, respectively, were retrospectively included in the study. The primary outcome was the adequate management of TIA defined as having had appropriate workup and antithrombotic treatment within 24 hours. A total of 141 patients were included in 2013 and 150 in 2016. There was a significant increase of complete (intracrania and extracranial) vessel imaging from 2013 to 2016 (n=42, 29.8% in 2013 vs. n=118, 78.7% in 2016; P<0.001). Computed tomography angiography was more often performed to assess intracranial and/or extracranial vessel imaging in 2016 compared with 2013 (n=54, 34.8% in 2013 vs. n=116, 77.3% in 2016; P<0.001). Overall, the rate of patients receiving adequate management significantly increased from 2013 to 2016 (n=36, 25.5% in 2013 vs. n=101, 67.3% in 2016; P<0.001). Implementation of a local care pathway, in accordance with current guidelines and adapted to local resources, improved TIA management in EDs, mostly by increasing the rate of vessel imaging by computed tomography angiography.

Endovascular and thrombolytic treatment eligibility in childhood arterial ischemic stroke.

To describe factors affecting eligibility for, and rates of utilization of, hyperacute therapy in children with acute ischemic stroke (AIS) following establishment of our institutional acute stroke treatment pathway in 2005. A retrospective analysis of a prospectively enrolled, single-center cohort was performed including children age 2 - <18 years with acute AIS from 2005 through 2017. Descriptive statistics were used to summarize clinical characteristics, presentation data, and Pediatric NIH Stroke Scale (PedNIHSS) scores that were abstracted from medical records. Assessment for eligibility and administration of hyperacute therapy was determined at the time of presentation according to the institutional stroke pathway. Of 90 children (median age at presentation 11.3 years, 36% female) with acute AIS, 5 (6%) received hyperacute therapy: 3 received intravenous tissue plasminogen activator (IV-tPA) alone, 1 received endovascular therapy (EVT) alone, and 1 received IV-tPA and EVT. Of 54 children (60%) who presented within 4.5h of time last seen well, 6 had PedNIHSS scores 6-24, no medical contraindication to IV-tPA, and a partial or complete vessel occlusion. Of 7 children >3 years old who presented after EVT became available at our hospital and within 6h of time last seen well with a PedNIHSS score 6-24, 3 (43%) had a large vessel occlusion (LVO). Two patients underwent EVT and the other patient was not transferred until >6h from time last seen well. Delay to presentation and diagnosis of childhood acute AIS, mild neurologic deficits at presentation, medical contraindications to IV-tPA, and lack of vessel occlusion on acute neuroimaging contribute to low rates of hyperacute treatment in children with acute AIS.

Application of Large Eddy Simulation to Predict Underwater Noise of Marine Propulsors. Part 1: Cavitation Dynamics

Marine propulsors are identified as the main contributor to a vessel’s underwater radiated noise as a result of tonal propeller noise and broadband emissions caused by its induced cavitation. To reduce a vessel’s signature, spectral limits are set for the propulsion industry, which can be experimentally obtained for a complete vessel at the full-scale; however, the prediction capability of the sound sources is still rudimentary at best. To adhere to the regulatory demands, more accurate numerical methods for combined turbulence and two-phase modeling for a high-quality prediction of acoustic sources of a propeller are required. Several studies have suggested implicit LES as a capable tool for propeller cavitation simulation. In the presented study, the main objective was the evaluation of the tip and hub vortex cavitating flows with implicit LES focusing on probable sound source representation. Cavitation structures for free-running propeller test cases were compared with experimental measurements. To resolve the structure of the tip vortex accurately, a priory mesh refinement was employed during the simulation in regions of high vorticity. Good visual agreement with the experiments and a fundamental investigation of the tip cavity structure confirmed the capability of the implicit LES for resolving detailed turbulent flow and cavitation structures for free-running propellers.

Pediatric May‐Thurner Syndrome—Systematic review and individual patient data meta‐analysis

BackgroundThe outcomes of deep vein thrombosis (DVT) in children with May‐Thurner Syndrome (MTS) remain unclear. ObjectivesThis systematic review and patient‐level meta‐analysis aims to describe the outcomes of children with MTS presenting with DVT. MethodsA systematic review of the published literature was performed. Data related to patients <18 years diagnosed with MTS and DVT was extracted. Risk of bias was assessed using the Murad criteria. Outcomes included vessel patency post‐treatment, DVT recurrence, and post‐thrombotic syndrome (PTS). Predictive and explanatory models were developed for these outcomes. ResultsIn total, 109 cases were identified (age range 4–17 years; 77 females) in 28 studies; 75% of patients had ≥1 additional risk factor for DVT. PTS was seen in 61% of patients, DVT recurrence in 38%, and complete vessel patency post‐treatment in 65%. The models developed to predict and explain PTS performed poorly overall. Recurrent thrombosis (adjusted for age and patency) predicted PTS (odds ratio [OR] 3.36, 95% confidence interval [CI] 1.28–8.82). DVT management strategies (adjusted for age and DVT characteristics) predicted vessel patency (OR 2.10, 95% CI 1.43–3.08). Lack of complete vessel patency (adjusted for age and thrombophilia) predicted recurrent DVT (OR 2.70, 95% CI 1.09–6.67). Sensitivity analyses showed the same direction of effects for all outcomes. ConclusionsPTS and DVT recurrence occur frequently in pediatric MTS. PTS prediction is complex and it was not possible to identify early predictors to guide clinical practice. Use of imaging‐guided therapy and thrombus burden predicted venous patency, and lack of patency predicted DVT recurrence.