Side Branch Research Articles

Side branch predilatation during percutaneous coronary bifurcation intervention: Long-term mortality analysis.

Side branch predilatation (SBPD) during coronary bifurcation interventions is a technique that is not recommended by the latest guidelines. However, the data about the clinical outcomes after SBPD are surprisingly few. The current study aimed to explore the association between SBPD and mortality in long-term follow-up. All patients with coronary bifurcation stenoses revascularized with percutaneous coronary intervention were included in a prospective registry. Patients with stable angina and a bifurcation lesion with ≥50% diameter stenosis were included in the current analysis. Patients were assigned to two groups - those with SBPD(+) and those without SBPD(-). Propensity score matching was performed to equalize the risk factors and severity of coronary artery disease between the groups. A Kaplan-Meier analysis with a log-rank test for between-group differences was also performed. From January 2013 to June 2021, 813 patients were included in the final study population. The mean age was 67 (10) years. After propensity score matching, 648 patients remained for analysis - 324 in each group. At a median follow-up of 57 months patients in the SBPD(+) group had a higher all-cause mortality (n = 107 (33%) vs. n = 98 [30.2%]; P = 0.045) and cardiovascular mortality (n = 82 [25.3%] vs. n = 70 [21.6%]; P = 0.03) when compared with SBPD(-) patients. SBPD was independently associated with all-cause and cardiovascular mortality. SBPD treatment of coronary bifurcation stenoses is associated with worse patient survival in the follow-up of up to 8 years. SBPD treatment gives better angiographic results, but this did not translate into better clinical outcomes.

Binary blends of polyamide 6 with aliphatic polyketone: the compatibility analysis of polymer components

The compatibility and interactions of polyamide 6 (PA6) and aliphatic polyketone (APK) were studied when they were mixed in a melt by extrusion. Using the relaxation spectrometry (RS) method, it was shown that the studied PA6/ APK blends had one glass transition temperature (Тg) located on the temperature scale between Тg of initial PA6 and APK. It was also found that in these mixtures, the PA6 b-relaxation peak, responsible for the local movement of small-scale structural units of the main chain and side branches, was socialized with the b-peak of APK. On this basis, conclusions were drawn about the compatibility of PA6 and APK at the segmental and small-scale level. The mutual influence of polymer components of PA6/APK blends on the dynamic shear modulus and the zG3 criterion is shown. The DSC analysis has revealed a slowdown in the crystallization of PA6 and APK in their blends, which is probably due to the formation of extensive interfacial (transitional) layers in the PA6/APK blend, in which crystallization of polymer components is hindered due to intermolecular interactions. The analysis of the IR-spectra in the range of 3000–3800 cm–1 has made it possible to establish the formation of hydrogen bonds between the polyamide –NH-groups and carbonyls –C=O, being part of APK, which contributes to an increase in the compatibility of the polymer components of the blend under study.

Prognostic value of a novel artificial intelligence-based coronary CTA-derived ischemia algorithm among patients with normal or abnormal myocardial perfusion

BackgroundAmong patients with obstructive coronary artery disease (CAD) on coronary computed tomography angiography (CTA), downstream positron emission tomography (PET) perfusion imaging can be performed to assess the presence of myocardial ischemia. A novel artificial-intelligence-guided quantitative computed tomography ischemia algorithm (AI-QCTischemia) aims to predict ischemia directly from coronary CTA images. We aimed to study the prognostic value of AI-QCTischemia among patients with obstructive CAD on coronary CTA and normal or abnormal downstream PET perfusion. MethodsAI-QCTischemia was calculated by blinded analysts among patients from the retrospective coronary CTA cohort at Turku University Hospital, Finland, with obstructive CAD on initial visual reading (diameter stenosis ≥50%) being referred for downstream 15O-H2O-PET adenosine stress perfusion imaging. All coronary arteries with their side branches were assessed by AI-QCTischemia. Absolute stress myocardial blood flow ≤2.3 ​ml/g/min in ≥2 adjacent segments was considered abnormal. The primary endpoint was death, myocardial infarction, or unstable angina pectoris. The median follow-up was 6.2 [IQR 4.4–8.3] years. Results662 of 768 (86%) patients had conclusive AI-QCTischemia result. In patients with normal 15O-H2O-PET perfusion, an abnormal AI-QCTischemia result (n ​= ​147/331) vs. normal AI-QCTischemia result (n ​= ​184/331) was associated with a significantly higher crude and adjusted rates of the primary endpoint (adjusted HR 2.47, 95% CI 1.17–5.21, p ​= ​0.018). This did not pertain to patients with abnormal 15O-H2O-PET perfusion (abnormal AI-QCTischemia result (n ​= ​269/331) vs. normal AI-QCTischemia result (n ​= ​62/331); adjusted HR 1.09, 95% CI 0.58–2.02, p ​= ​0.794) (p-interaction ​= ​0.039). ConclusionAmong patients with obstructive CAD on coronary CTA referred for downstream 15O-H2O-PET perfusion imaging, AI-QCTischemia showed incremental prognostic value among patients with preserved perfusion by 15O-H2O-PET imaging, but not among those with reduced perfusion.

The Randomized, Multicenter, Open-Label, Controlled POLBOS 3 Trial Comparing Regular Drug-Eluting Stents and the Sirolimus-Eluting BiOSS LIM C Dedicated Coronary Bifurcation Stent: Four-Year Results.

This multicenter, randomized study aimed to compare the sirolimus-eluting BiOSS LIM C dedicated coronary bifurcation stent with second-generation -limus drug-eluting stents (rDESs) in the treatment of non-left main (non-LM) coronary bifurcation. The deployment of a single stent in the main vessel-main branch across a side branch was the default strategy in all patients. The primary endpoint was the rate of major cardiovascular events (cardiac death, myocardial infarction, and target lesion revascularization) at 48 months. We enrolled 230 patients, allocating 116 patients to the BiOSS LIM C group and 114 patients to the rDES group. Most procedures were elective (BiOSS vs. rDES: 48.3% vs. 59.6%, p = 0.09) and performed in bifurcations within the left anterior descending/diagonal branch (BiOSS vs. rDES: 51.7% vs. 61.4%, p = 0.15). At 48 months, there were no statistically significant differences between the BiOSS and rDES groups in terms of major adverse cardiovascular events (MACE), cardiac death, myocardial infarction (MI), or target lesion revascularization (TLR) as follows: MACEs-18.1% vs. 14.9%, HR 1.36, 95% CI 0.62-2.22, and p = 0.33; cardiac death-4.3% vs. 3.5%, HR 1.23, 95% CI 0.33-4.56, and p = 0.75; MI-2.6% vs. 3.5%, HR 0.73, 95% CI 0.17-3.23, and p = 0.68; and TLR-11.2% vs. 7.9%, HR 1.66, 95% CI 0.75-3.71, and p = 0.21. The implantation success rate of the BiOSS LIM C stent was very high, and the cumulative MACE rates were promising. The POLBOS 3 trial sets an important benchmark for treating non-LM coronary bifurcations (ClinicalTrials.gov NCT03548272).

The chronic pancreatitis (CP) Type Cambridge 2 as a cause of unclear upper abdominal pain: a radiologically underestimated diagnosis

AbstractThe time interval from symptom onset to the diagnosis of chronic pancreatitis (CP) remains disproportionately long today due to nonspecific symptoms and the absence of a definitive laboratory marker. Nevertheless, mortality is increased by 3.6 times compared to the general population. Additionally, the risk of developing pancreatic carcinoma is 16 times higher in the presence of CP. According to the current S3 guideline, the morphological staging of CP should be based on the Cambridge Classification for CT/MRCP. Most radiologists morphologically associate CP with Cambridge Stage 4, which is characterized by classic calcifications. The subtle morphologies of earlier Cambridge Stages are often unrecognized, leading to delayed diagnosis. The aim of this study was to diagnose CP at Cambridge Stage 2 as the cause of unexplained upper abdominal discomfort.A retrospective analysis was conducted on 266 patients with unexplained upper abdominal pain who underwent outpatient MRI with MRCP between January 1, 2021, and October 1, 2023. The criteria for Cambridge Stage 2 were evaluated: pancreatic duct in the corpus measuring between 2 and 4 mm, pancreatic hypertrophy, cystic changes < 10 mm, irregularities in the duct, or > 3 pathological side branches. Patients with known tumors or other leading diagnoses, which explained the discomfort, were excluded.25 patients (15 female, 10 male) met the criteria for CP Stage 2 (9%). Ductal dilation between 2 and 4 mm was visible in 21 cases. Pancreatic hypertrophy was observed in six cases. Cystic changes < 10 mm were identified in three cases. Irregularities in the duct (“wavy duct”) were diagnosed in 19 patients. Dilation of > 3 side branches was recognized in 17 cases. Lipase levels were additionally determined, with 13 patients showing pathologically elevated levels (> 60 U/l).CP at Cambridge Stage 2 is an important and underestimated diagnosis in patients with unexplained upper abdominal pain in the outpatient setting. Radiologists should pay attention not only to common signs like calcifications, large cysts, or duct strictures but also to subtle changes such as duct irregularities (“wavy duct configuration”) and pathologically dilated side branches, which could lead to a significantly earlier diagnosis of CP. Lipase determination may be an additional indication of chronic pancreatitis in this context.

Midterm outcomes of endovascular repair for abdominal aortic aneurysm using the cuff-first technique to prevent type II endoleaks

ObjectiveThe aim of this study was to evaluate the initial and midterm outcomes of endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA) using the cuff-first technique (CFT) to prevent type II endoleak (T2EL). MethodsCFT involves deploying an aortic cuff inside the AAA to cover the ostium of the aortic side branch vessels before deploying the main body. We performed a retrospective review of all patients undergoing EVAR with CFT or side branch embolization (SBE) for AAAs at The Jikei University Hospital between 2016 and 2022. Primary endpoint was the rate of aneurysm sac shrinkage. Secondary endpoints were procedure time, radiation exposure, technical and clinical success rates, occurrence of T2EL, and freedom from reintervention or aneurysm-related death. ResultsOf 406 patients who underwent EVAR for AAAs, CFT was utilized in 56 (CFT group) and SBE in 35 (SBE group); all 91 patients were included in this study. There were no differences in patient demographics between groups, but there were differences in patency rate of the inferior mesenteric artery and absent intraluminal thrombus. The technical success rate per target vessel in the CFT and SBE group was 97.8% and 91.8%, and the clinical success rate was 91.0% and 100%, respectively. The median procedure time was shorter for CFT than for SBE: CFT, 10 (interquartile range [IQR], 6-14) minutes vs SBE, 25 (IQR, 18.5-45) minutes; P < .05), and median radiation exposure was lower for CFT than for SBE (CFT, 1455 (IQR, 840-2634) mGy vs SBE, 2353 (IQR, 1552-3586) mGy; P < .05). During the median follow-up of 25 months (IQR, 12.5-47 months), sac shrinkage occurred at similar rates in both groups (CFT, 37.5% vs SBE, 40.0%; P = .812), and there were no differences in freedom from reintervention (CFT, 96.2% and 91.4% at 12 and 36 months vs SBE, 100% and 89.5% at 12 and 36 months; log-rank P = .761) and freedom from aneurysm-related death (100% at 36 months in both groups; log-rank P = .440). The odds ratio of CFT vs SBE for sac regression was calculated by adjusting for inferior mesenteric artery patency and absent intraluminal thrombus, resulting in no statistical significance (odds ratio, 1.231; 95% confidence interval, 0.486-3.122). ConclusionsCFT is feasible with a shorter procedure time and lower radiation exposure than SBE and comparable mid-term outcomes, including sac shrinkage rate, compared with SBE. We believe that CFT, if anatomically suitable, is an alternative to SBE for the prevention of T2EL during EVAR.

Inkjet printed acrylate-urethane modified poly(3,4-ethylenedioxythiophene) flexible conductive films

Abstract Flexible electronics is a new generation of electronic devices in which electronic components are integrated into flexible substrates. It is used in the fabrication of displays, solar cells, integrated circuits, and increasingly in the fabrication of electronic skin (E-skin), which can mimic the properties of human skin by being able to follow skin movements and flexures without loss of mechanical and electrical properties. E-skin is suitable for integrating various sensors to monitor personal health. Conductive polymers are used in flexible electronics due to their electrical conductivity, low mass, and stability. However, their main disadvantage is their brittleness, which is why they don’t possess flexibility property without modification. Therefore, in this work, the conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) was used as the main chain and the side branches of poly(acrylate-urethane) (PAU) were grafted onto it by atom transfer radical polymerization (ATRP) onto it, obtaining the grafted copolymer PEDOT-g-PAU. In this way, the main chain of PEDOT retains the property of electrical conductivity without losing conjugation, while the side branches of PAU have the ability to crosslink non-covalently through hydrogen bonds with PAU side branches of adjacent polymer molecules due to the presence of oxygen in their structure. The presence of hydrogen bonds allows increasing the stretchability and flexibility of the material, and they also have the ability to spontaneously renew themselves when they break due to excessive stress. Three different synthesis conditions were used to obtain polymers of different structure, which were characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and measurement of electrical conductivity with a four-point probe (4PP) method. The obtained graft copolymer was prepared in the form of ink and printed on a polyurethane (PU) substrate using inkjet technique. The conductivity of the printed layer, its elongation and adhesion were investigated, while possible delamination of the printed polymer layer was also monitored. The results showed that the PEDOT-g-PAU copolymer was successfully synthesized and inkjet printing on PU film was successful. The obtained material has satisfactory electrical and mechanical properties and could be used for the integration of fully functional biosensors with further optimization of the composition.

Mid-term results of "off-label" use of the Endurant stentgraft in patients with infrarenal abdominal aortic aneurysms.

EVAR is the preferred treatment modality for patients with an infrarenal abdominal aortic aneurysm with suitable anatomy. Each manufacturer of aortic stentgrafts has specific anatomic requirements. In some patients, it is not possible to adhere to the instructions for use, but alternative treatment is also not possible. In these patients, EVAR can be performed outside instructions for use. In this study, all consecutive patients in whom an Endurant II or IIS stentgraft was used between 1 January and 31 December were reviewed. We compared the two patient groups in whom this stentgrafts was used outside and inside instructions for use. Patients with planned adjuvant therapy, for example, chimney procedure or iliac side branches, were excluded. In 74 of 178 (41.6%) patients, the instructions for use were not adhered. The main reason was pathology of the aortic neck. There were more patients with type IA endoleak, this difference was borderline significant (p = .06). There were more patients with limb occlusion in the early postoperative period, but at the end of the follow-up period, the incidence was comparable. Aneurysm-related mortality and all-cause mortality were comparable in both groups. In this study, real-life experience with the Endurant II and IIS stentgraft is described. Non-adherence with instructions for use was associated with a higher risk of endoleak type IA (p = .06). In the early postoperative period, there were more patients with limb occlusion; this finding was not observed anymore at the end of the follow-up period.

Five-year outcomes of double kissing mini-culotte stenting vs. mini-culotte stenting using drug-eluting stents for the treatment of true coronary bifurcation lesions.

This study aimed to compare the clinical outcomes of double kissing mini-culotte (DKMC) stenting with those of mini-culotte (MC) stenting in treating patients with true coronary bifurcation lesions (CBLs) in the clinical real world. This retrospective observational cohort study included 180 consecutive patients with true CBLs (Medina type 1,1,1; 1,0,1; 0,1,1). All eligible patients underwent coronary angiography and percutaneous coronary intervention with two-stent techniques in our hospital; among them, 97 received DKMC treatment and 83 MC treatment. The primary clinical endpoints were the major adverse cardiovascular events (MACE), which included cardiac death, myocardial infarction, and target vessel/lesion revascularization (TVR/TLR). The secondary endpoints were stent thrombosis, in-stent restenosis, and individual components of MACE. Quantitative coronary angiography analysis (at 5 years) revealed that late lumen loss (0.25 ± 0.41 mm vs. 0.14 ± 0.32 mm, P = 0.032) and segmental diameter restenosis of the side branch (27.84 ± 12.34% vs. 19.23 ± 9.76%, P = 0.016) were lower in the DKMC treatment group than that in the MC treatment group. Notably, compared to that in the MC treatment group, the cumulative event rate of MACE at 5 years (22.8% vs. 8.3%, P = 0.007) and TVR/TLR (17.7% vs. 6.3%, P = 0.018) was higher in the DKMC treatment group, driven mainly by TVR/TLR. Especially, the DKMC group was related to a significant reduction in the primary and secondary endpoints in high-risk patients. DKMC treatment was associated with less late lumen loss and restenosis in the side branch and a lower rate of cumulative MACE and TVR/TLR. DKMC treatment is more effective for treating true CBLs than MC treatment; however, these findings warrant further confirmation through a randomized clinical trial.

Management of depth to achieve timely arteriovenous fistula utilization

ObjectiveFailure to achieve timely arteriovenous fistulae (AVFs) utilization due to excessive depth (>6 mm) remains an ongoing concern for dialysis access. This study evaluates the outcomes of radiocephalic (RCF) and brachiocephalic (BCF) fistula elevation required for access utilization. MethodsA retrospective review of all patients undergoing first-time autologous access over 10 years was undertaken. RCF and BCF were analyzed, and cases of initial access failure due to depth alone were selected for study. Primary and staged brachio-basilic AVF were excluded. Outcomes of early thrombosis, line placement, maturation (successful progression to hemodialysis [HD), reintervention, and functional dialysis (continuous HD for 3 consecutive months) were examined. ResultsFrom January 2012 to December 2022, 1733 patients (67% female; mean age, 61 ± 14 years) underwent autologous AVF placement. Of these, 298 patients (17%) had depth-related AVF access issues (BCF, 71% and RCF, 29%). Nineteen percent of these AVFs underwent a primary balloon-assisted maturation (BAM), and 2% had side branch coil embolization before consideration for elevation. The average time to intervention for depth was 11 ± 4 weeks after primary creation. During elevation, side branch ligation occurred in 38% of cases, and 15% underwent intraoperative BAM, The pre-elevation depth was 8.2 ± 3.1 mm, and the mean post-elevation depth was 4.7 ± 2.9 mm (P = .002). Early thrombosis (<18 days) occurred in 4% of cases. There was no mortality, and the 30-day major adverse cardiac event rate was 2%, with a 30-day morbidity of 5%, which was driven by wound issues. Six percent of the AVFs underwent follow-up BAM within 3 months. Mean maturation of the AVFs was 74% ± 3% vs 72% ± 3% (P = .58) for the elevation vs no-elevation groups at 24 weeks, respectively. However, there was an increase in tunneled central line placement in pre-emptive fistula patients due to the delay in maturation (elevation, 17% vs no-elevation, 8%; P = .008). There was a mean successful access time of 6 ± 3 weeks after elevation (16 ± 4 weeks after access creation). There was a median of 2.4 secondary interventions per year after elevation compared with a median of 2.7 secondary interventions per year without elevation. Mean access functionality was 68% ± 8% vs 75% ± 8% at 3 years for the elevation vs no-elevation groups, respectively (P = .25). ConclusionsElevation of deep BCF and RCF occurs late after placement but can be successfully achieved with low morbidity and satisfactory long-term functionality. It results in an increase in tunneled central line placement in pre-emptive fistula patients. Elevation is a valuable adjunct to AVF maturation and enhances an autologous access policy.

Plug-Based Embolization Techniques of Aortic Side Branches during Standard and Complex Endovascular Aortic Repair.

Vascular plugs are an evolving family of vessel occluders providing a single-device embolization system for large, high-flow arteries. Nitinol mesh plugs and polytetrafluoroethylene membrane plugs are available in different configurations and sizes to occlude arteries from 3 to 20 mm in diameter. Possible applications during complex endovascular aortic procedures are aortic branch embolization to prevent endoleak or to gain an adequate landing zone, directional branch occlusion, and false lumen embolization in aortic dissection. Plugs are delivered through catheters or introducers, and their technical and clinical results are comparable to those of coil embolization. Plugs are more accurate than coils as repositionable devices, less prone to migration, and have fewer blooming artifacts on postoperative computed tomography imaging. Their main drawback is the need for larger delivery systems. This narrative review describes up-to-date techniques and technology for plug embolization in complex aortic repair.

Elastic Shape Analysis of Tree-Like 3D Objects Using Extended SRVF Representation.

How can one analyze detailed 3D biological objects, such as neuronal and botanical trees, that exhibit complex geometrical and topological variation? In this paper, we develop a novel mathematical framework for representing, comparing, and computing geodesic deformations between the shapes of such tree-like 3D objects. A hierarchical organization of subtrees characterizes these objects - each subtree has a main branch with some side branches attached - and one needs to match these structures across objects for meaningful comparisons. We propose a novel representation that extends the Square-Root Velocity Function (SRVF), initially developed for Euclidean curves, to tree-shaped 3D objects. We then define a new metric that quantifies the bending, stretching, and branch sliding needed to deform one tree-shaped object into the other. Compared to the current metrics such as the Quotient Euclidean Distance (QED) and the Tree Edit Distance (TED), the proposed representation and metric capture the full elasticity of the branches (i.e., bending and stretching) as well as the topological variations (i.e., branch death/birth and sliding). It completely avoids the shrinkage that results from the edge collapse and node split operations of the QED and TED metrics. We demonstrate the utility of this framework in comparing, matching, and computing geodesics between biological objects such as neuronal and botanical trees. We also demonstrate its application to various shape analysis tasks such as (i) symmetry analysis and symmetrization of tree-shaped 3D objects, (ii) computing summary statistics (means and modes of variations) of populations of tree-shaped 3D objects, (iii) fitting parametric probability distributions to such populations, and (iv) finally synthesizing novel tree-shaped 3D objects through random sampling from estimated probability distributions.

The Balloon-Assisted Double-Kissing T-Stenting Technique: Concept, In Vitro Model, and Case Examples

BackgroundIn complex bifurcation percutaneous coronary intervention, 2-stent strategies are often required. Commonly used 2-stent techniques can lead to suboptimal results due to their complexity. We developed the balloon-assisted double-kissing T-stenting (DKT) technique, which uses balloons to optimize stent placement, delivery, and final architecture. MethodsWith the balloon-assisted DKT technique, a balloon is inflated into the main branch (MB) to identify the best position of the side-branch (SB) stent instead of relying on angiography. DKT aims at supporting the SB ostium with stent crowns instead of distorted open cell(s), by achieving a longitudinal deformation with minimal crush of the SB stent upon implantation of the MB stent. This hypothesis was tested on a bench model. We report how the technique was performed in 2 cases and provide intracoronary imaging of the results. ResultsAs hypothesized, DKT resulted in a longitudinal accordion-like deformation and minimal crush effect on bench. The SB ostium was supported by stent crowns. The SB wall opposed to the carina was well covered with crowns from the MB stent after proximal optimization technique and final kissing. The technique was successfully used in 2 complex left main cases with perfect coverage of the SB ostium as assessed with intracoronary imaging. ConclusionsThe balloon-assisted DKT is a simple technique that combines strengths of double-kissing crush and culotte techniques, results in appropriate SB ostium coverage, and deserves further investigation.

A Multi-Target Identification and Positioning System Method for Tomato Plants Based on VGG16-UNet Model

The axillary buds that grow between the main and lateral branches of tomato plants waste nutrients and lead to a decrease in yield, necessitating regular removal. Currently, these buds are removed manually, which requires substantial manpower and incurs high production costs, particularly on a large scale. Replacing manual labor with robots can lead to cost reduction. However, a critical challenge is the accurate multi-target identification of tomato plants and precise positioning for axillary bud removal. Therefore, this paper proposes a multi-target identification and localization method for tomato plants based on the VGG16-UNet model. The average intersection and pixel accuracies of the VGG16-UNet model after introducing the pretrained weights were 85.33% and 92.47%, respectively, which were 5.02% and 4.08% higher than those of the VGG16-UNet without pretrained weights, achieving the identification of main branches, side branches, and axillary bud regions. Then, based on the multi-objective segmentation of the tomato plants in the VGG16-UNet model, the regions of the axillary buds in the tomato plants were identified by HSV color space conversion and color threshold range selection. Morphological dilation and erosion operations were used to remove noise and connect adjacent regions of the same target. The endpoints and centroids of the axillary buds were identified using the feature point extraction algorithm. The left and right positions of the axillary buds were judged by the relationship between the position of the axillary bud centroid and the position of the main branch. Finally, the coordinate parameters of the axillary bud removal points were calculated using the feature points to determine the relationship between the position of the axillary bud and the position of the branch. Experimental results showed that the average accuracy of the axillary bud pruning point recognition was 85.5%.

Performance study and improvement of space-folded metamaterial muffler for pipe under grazing flow

A space-folded metamaterial muffler (SMM) for pipe noise attenuation was proposed in this paper, and an improved space-folded metamaterial muffler (ISMM) was formed by arranging wire meshes at the branch inlet. Under the absence of flow and grazing flow, analytical models of SMM and ISMM were developed based on the wave expansion method and Green's function, and correspondingly, the computational fluid dynamics - linear Navier-Stokes (CFD-LNS) numerical models were established. The acoustic characteristics of responsive space (RS) were described through the complex frequency plane. The transmission coefficient of SMM was obtained and verified by sound transmission loss experiments. The results indicate that due to the thermal-viscous effects, the minimum transmission coefficient of RS cannot reach 0. Therefore, the thermal-viscous effect is one of the critical factors. By the parameter retrieving method, it is clarified that the SMM is a single-negative acoustic metamaterial. The effect of the grazing velocity on the transmission coefficient and impedance was revealed quantitatively. The grazing velocity is positively correlated with impedance at the side branch inlet and negatively correlated with total impedance. Therefore, an increase in the grazing velocity will weaken the muffler performance. Since the CFD-LNS model cannot characterize aerodynamic noise, a computational aeroacoustics (CAA) model was established for SMM and ISMM. Numerical results show that the velocity and vorticity at the side branch inlet significantly decrease due to the wire mesh. When Ma is 0.1, 0.05, and 0.01, ISMM reduces aerodynamic noise by 6.11 dB, 9.19 dB, and 2.76 dB, respectively, compared to SMM. Therefore, ISMM has better aerodynamic noise suppression capability. Finally, noise reduction experiments of the ISMM under the grazing flow were performed in an anechoic chamber, and the effectiveness of the ISMM in practical applications was verified by acoustic imaging and spectrogram results.

Optimizing Matrix Capsule Networks for Contraband detection Research

An optimized matrix capsule network is proposed for the problem of contraband in parcels with different poses, different sizes, random occlusion and sample imbalance. The network improves the recognition accuracy with the help of the matrix capsule network's recognition ability for object poses, and is mainly composed of a multi-branch feature extraction network and a side branch matrix capsule network, which is used to extract large and small targets; the side branch matrix capsule network uses a larger capsule convolution kernel, which is capable of detecting larger targets, and uses the operation of randomly discarding the capsules in the side branch, which makes the parameter amount to be reduced while enhancing the learning ability of the network. The region of interest of the network is obtained by using heat map approach with the help of weight back propagation mapping back to the original map to localize the contraband. Through a large number of experiments on the SIXray dataset, it is proved that the network in this paper improves the detection accuracy by 9.43% and the processing speed of the model by about 1/3 compared with the original capsule network.

Side branch embolization before endovascular abdominal aortic aneurysm repair to prevent type II endoleak: A prospective multicenter study

PurposeThe purpose of the study was to evaluate the efficacy and safety of pre-emptive transcatheter arterial embolization (P-TAE) of aortic side branches to prevent type II endoleak in patients with abdominal aortic aneurysm after endovascular abdominal aneurysm repair (EVAR). Materials and methodsThis multicenter, prospective, single-arm trial enrolled 100 patients with abdominal aortic aneurysm from nine hospitals between 2018 and 2021. There were 85 men and 15 women, with a mean age of 79.6 ± 6.0 (standard deviation) years (range: 65–97 years). P-TAE was attempted for patent aortic side branches, including the inferior mesenteric artery, lumbar arteries, and other branches. The primary endpoint was late type II endoleak incidence at 6 months post-repair. Secondary endpoints included changes in aneurysmal sac diameter at 6- and 12 months, complications, re-intervention, and aneurysm-related mortality. Aneurysm sac changes at 6- and 12 months was compared between the late and no-late type II endoleak groups. ResultsCoil embolization was successful in 80.9% (321/397) of patent aortic side branches, including 86.3% of the inferior mesenteric arteries, 80.3% of lumbar arteries, and 55.6% of other branches without severe adverse events. Late type II endoleak incidence at 6 months was 8.9% (8/90; 95% confidence interval: 3.9–16.8%). Aneurysm sac shrinkage > 5 mm was observed in 41.1% (37/90) and 55.3% (47/85) of the patients at 6- and 12-months post-EVAR, respectively. Patients with late type II endoleak had less aneurysm sac shrinkage than those without type II endoleak at 12 months (˗0.2 mm vs. ˗6.0 mm; P = 0.040). No patients required re-intervention for type II endoleak, and no aneurysm-related mortalities occurred. ConclusionP-TAE is safe and effective in preventing type II endoleak, leading to early sac shrinkage at 12 months following EVAR.

Evaluation of models of sequestration flow in coronary arteries—Physiology versus anatomy?

Background:Myocardial ischaemia results from insufficient coronary blood flow. Computed virtual fractional flow reserve (vFFR) allows quantification of proportional flow loss without the need for invasive pressure-wire testing. In the current study, we describe a novel, conductivity model of side branch flow, referred to as ‘leak’. This leak model is a function of taper and local pressure, the latter of which may change radically when focal disease is present. This builds upon previous techniques, which either ignore side branch flow, or rely purely on anatomical factors. This study aimed to describe a new, conductivity model of side branch flow and compare this with established anatomical models. Methods and results:The novel technique was used to quantify vFFR, distal absolute flow (Qd) and microvascular resistance (CMVR) in 325 idealised 1D models of coronary arteries, modelled from invasive clinical data. Outputs were compared to an established anatomical model of flow. The conductivity model correlated and agreed with the reference model for vFFR (r = 0.895, p < 0.0001; ＋0.02, 95% CI 0.00 to ＋ 0.22), Qd (r = 0.959, p < 0.0001; −5.2 mL/min, 95% CI −52.2 to ＋13.0) and CMVR (r = 0.624, p < 0.0001; ＋50 Woods Units, 95% CI −325 to ＋2549). Conclusion:Agreement between the two techniques was closest for vFFR, with greater proportional differences seen for Qd and CMVR. The conductivity function assumes vessel taper was optimised for the healthy state and that CMVR was not affected by local disease. The latter may be addressed with further refinement of the technique or inferred from complementary image data. The conductivity technique may represent a refinement of current techniques for modelling coronary side-branch flow. Further work is needed to validate the technique against invasive clinical data.

Cost-revenue aspects of endovascular treatment of distal aortic arch pathologies with respect to the introduction of a new thoracic side-branch prosthesis

The standard vascular surgical procedure (SV) for the treatment of distal aortic arch pathologies involves ahybrid approach using aleft carotid-subclavian bypass and thoracic endovascular aortic repair. Considering the introduction of athoracic side branch prosthesis (TBE), the aim of this study was to analyze the cost-revenue aspects of both procedures. Aretrospective analysis was conducted on cases treated by SV from 2017 to 2022. To draw conclusions regarding the use of TBE, the main diagnoses and procedures of SV were recoded based on current classifications (ICD/OPS 2023) for revenue calculations and regrouped according to aG-DRG 2023. An OPS modification and regrouping were performed for modeling TBE revenues. Atotal of 13 cases were identified (mean age 62.5 ± 13.8 years; 10males). After regrouping, the following DRGs were obtained: F42Z in N = 5, F51A in N = 4, F08B in N = 2, and F07A and F36B each in N = 1. The total revenue after regrouping was € 666,514.13, including an additional payment (ZE) of € 132,729.14. With the modeled application of TBE, atotal revenue of € 659,212.19 was achieved. Compared to SV, this represents arevenue decrease of € 16,886.71 (changed DRG), but with an increase in ZE revenue by € 65,559.78 (different ZE). The use of TBE resulted in asaving of 74occupancy days, including 13.5 days in intensive care. Acost coverage seems probable with achange in the procedure, despite the yet to be determined pricing of TBE. This is highly dependent on the coding quality and the future development of ZE, given the annually changing DRG relative weights. Precise and transparent performance and cost documentation are essential for determining the pricing.

Initial Outcomes of the Gore TAG Thoracic Branch Endoprosthesis for Endovascular Repair of Blunt Thoracic Aortic Injury

Endovascular repair of blunt thoracic aortic injury (BTAI) has dramatically reduced the morbidity and mortality of intervention. Injuries requiring zone 2 coverage of the aorta traditionally require left subclavian artery (LSA) sacrifice or open revascularization. Furthermore, these injuries are associated with an increased risk of in-hospital mortality and long-term morbidity. Here we report 1-year outcomes of total endovascular repair of BTAI with the GORE® TAG® Thoracic Branch Endoprosthesis for LSA preservation. Across 34 investigative sites, 9 patients with BTAI requiring LSA coverage were enrolled in a nonrandomized, prospective study of a single-branched aortic endograft. The thoracic branch endoprosthesis device allows for graft placement proximal to the LSA and incorporates a single side branch for LSA perfusion. This initial cohort included 8 male and 1 female patient with a median age of 43 (22,76) and 12months of follow-up. Five total years of follow-up are planned. All participants had grade 3 BTAI. All procedures took place between 2018 and 2019. The median injury severity score was 2 (0, 66). The median procedure time was 109min (78, 162). All aortic injuries were repaired under general anesthesia and with heparinization. A spinal drain was used in one patient. Post-deployment balloon angioplasty was conducted in one case at the distal landing zone. There was one asymptomatic LSA branch occlusion 6months after repair. It was attributed to the purposeful proximal deployment of the branch stent to accommodate an early vertebral takeoff. The occlusion did not require revascularization. There were no strokes, mortalities, or aortic adverse events (migration, endoleak, native aortic expansion, dissection, or thrombosis) through 12months of follow-up. Initial cohort outcomes suggest that endovascular repair of zone 2 BTAI is feasible and has favorable outcomes using the thoracic branch device with LSA preservation. Additional cases and longer-term follow-up are required for a definitive assessment of the device'ssafety and durability in traumatic aortic injuries.