Conventional Vessel Research Articles

Prediction of endovascular leaks after thoracic endovascular aneurysm repair though machine learning applied to pre-procedural computed tomography angiographs.

To predict endoleaks after thoracic endovascular aneurysm repair (TEVAR) we submitted patient characteristics and vessel features observed on pre- operative computed tomography angiography (CTA) to machine-learning. We evaluated 1-year follow-up CT scans (arterial and delayed phases) in patients who underwent TEVAR for the presence or absence of an endoleak. We evaluated the effect of machine learning of the patient age, sex, weight, and height, plus 22 vascular features on the ability to predict post-TEVAR endoleaks. The extreme Gradient Boosting (XGBoost) for ML system was trained on 14 patients with- and 131 without endoleaks. We calculated their importance by applying XGBoost to machine learning and compared our findings between with those of conventional vessel measurement-based methods such as the 22 vascular features by using the Pearson correlation coefficients. Pearson correlation coefficient and 95% confidence interval (CI) were r = 0.86 and 0.75 to 0.92 for the machine learning, r = -0.44 and -0.56 to -0.29 for the vascular angle, and r = -0.19 and -0.34 to -0.02 for the diameter between the subclavian artery and the aneurysm (Fig.3a-c, all: p < 0.05). With machine-learning, the univariate analysis was significant higher compared with the vascular angle and in the diameter between the subclavian artery and the aneurysm such as the conventional methods (p < 0.05). To predict the risk for post-TEVAR endoleaks, machine learning was superior to the conventional vessel measurement method when factors such as patient characteristics, and vascular features (vessel length, diameter, and angle) were evaluated on pre-TEVAR thoracic CTA images.

Assessment for Carotid Atherosclerotic Plaque Using Vessel Wall Magnetic Resonance Imaging: A Multireader ROC Study to Determine Optimal Sequence for Detecting Vessel Wall Calcification

Introduction: We aimed to compare conventional vessel wall MR imaging techniques and quantitative susceptibility mapping (QSM) to determine the optimal sequence for detecting carotid artery calcification. Methods: Twenty-two patients who underwent carotid vessel wall MR imaging and neck CT were enrolled. Four slices of 6-mm sections from the bilateral internal carotid bifurcation were subdivided into 4 segments according to clock position (0–3, 3–6, 6–9, and 9–12) and assessed for calcification. Two blinded radiologists independently reviewed a total of 704 segments and scored the likelihood of calcification using a 5-point scale on spin-echo imaging, FLASH, and QSM. The observer performance for detecting calcification was evaluated by a multireader, multiple-case receiver operating characteristic study. Weighted κ statistics were calculated to assess interobserver agreement. Results: QSM had a mean area under the receiver operating characteristic curve of 0.85, which was significantly higher than that of any other sequence (p < 0.01) and showed substantial interreader agreement (κ = 0.68). A segment with a score of 3–5 was defined as positive, and a segment with a score of 1–2 was defined as negative; the sensitivity and specificity of QSM were 0.75 and 0.87, respectively. Conclusion: QSM was the most reliable MR sequence for the detection of plaque calcification.

Effect of an Inclined Slots on the Power Consumption and Vortices Size in a Rushton Turbine Agitated Tank

Mechanical agitation in baffled vessels with turbines plays a vital role in achieving homogeneous fluid mixing and promoting various transfer operations. Therefore, designing vessels with optimal energy efficiency and flow dynamics is essential to enhance operational performance and eliminate flow perturbations. Hence, the present research focuses on a numerical investigation of the impact of inclined slots with different angles installed at the sidewall of a cylindrical vessel equipped with a Rushton turbine. This study explores power consumption and vortex size while considering various rotation directions of the impeller with different rotation speeds. The numerical simulations are conducted for Reynolds numbers ranging from 104 to 105, using the RANS k-ε turbulence model to govern the flow inside the stirred vessel, accounting for mass and momentum balances. The results have shown that the installation of slots reduces power consumption and vortex size compared to conventional vessel configurations. Moreover, increasing the slot angle from 0 to 32.5° further reduces energy consumption and vortex size, especially with negative rotation speeds. On the other hand, increasing the Reynolds numbers leads to a decrease in power consumption and an increase in vortex size. The present research therefore proposes a design for constructing Rushton-turbine stirred vessels offering optimal operation, characterized by reduced energy consumption and minimized vortex size.

A Space-Refine Paradigm for Automatic Carotid Artery Centerline Extraction in Magnetic Resonance Imaging.

Vessel centerline extraction is essential for carotid stenosis assessment and atherosclerotic plaque identification in clinical diagnosis. Simultaneously, it provides a region of interest identification and boundary initialization for computer-assisted diagnosis tools. In magnetic resonance imaging (MRI) cross-sectional images, the lumen shape and vascular topology result in a challenging task to extract the centerline accurately. To this end, we propose a space-refine framework, which exploits the positional continuity of the carotid artery from frame to frame to extract the carotid artery centerline. The proposed framework consists of a detector and a refinement module. Specifically, the detector roughly extracts the carotid lumen region from the original image. Then, we introduce a refinement module that uses the cascade of regressors from a detector to perform sequence realignment of lumen bounding boxes for each subject. It improves the lumen localization results and further enhances the centerline extraction accuracy. Verified by large carotid artery data, the proposed framework achieves state-of-the-art performance compared to conventional vessel centerline extraction methods or standard convolutional neural network approaches.Clinical relevance- Our proposed framework can be used as an important aid for physicians to quantitatively analyze the carotid artery in clinical practice. It is also used as a new paradigm for extracting the centerline of carotid vessels in computer-assisted tools.

Process analysis of a molten carbonate fuel cell on-board application to reduce vessel CO2 emissions

The International Maritime Organization has promulgated a set of regulations that demand for the reduction of CO2 emission. Specifically, a reduction of 40% and 70% compared to 2008 is required by 2030 and 2050, respectively. A rough estimate suggests that 20% can be obtained with speed and routes optimisation, while the residual reduction requires the use of more sustainable technology. To achieve the latter objective in a short time, the authors propose existing vessel retrofitting using molten carbonate fuel cells (MCFCs). Indeed, MCFCs allow for additional energy production while capturing CO2 emitted by the conventional vessel engines. Using the software Aspen Plus coupled with the homemade SIMFC code, the system has been simulated and the results show the proposed solution as very promising. In particular, also the impact on the performance of an additional membrane system for CO2 finishing and of different recycle configurations for unreacted H2 recovery is discussed.

Development of automatic control methods of vessel rotation around the pivot point without drift

The object of research is the processes of automatic control of the vessel rotation around the pivot point with zero drift. In recent years, the number of vessels and their sizes has increased significantly, while the size of ports has grown much more slowly. There is an urgent need to optimize control processes, especially in compressed waters. One of the directions of such optimization is the use of the pivot point concept – an alternative vision of the vessel movement during its maneuvering. It is shown that the circulation radius and the position of the vessel on circulation are determined by the pivot point abscissa and ordinate. Linearized models of the two most common control schemes are considered: the control scheme of a single-screw conventional vessel without a bow thruster and the control scheme of a single-screw conventional vessel with a bow thruster. For the steady state of each of these schemes, controls were obtained that ensure the circulation of the vessel around a pivot point position without drift angle. This makes it possible to reduce the width of the traffic lane, increase traffic safety, reduce hydrodynamic resistance and fuel consumption, create favorable conditions for carrying out technological operations, for example, mooring, and reduce the influence of the human factor on control processes. The workability and effectiveness of the developed methods were verified by mathematical modeling of the MSС Container Ship (Dis. 32025t) automatic mooring without drift angle on the imitation modeling stand created by the authors on the basis of the Navi Trainer 5000 navigation simulator. The obtained capabilities are explained by the use of the mathematical model of the vessel in the on-board controller of the automated system and modern mathematical apparatus. The developed methods can be used on the vessels, provided to integration into the existing automated system of an on-board controller with open architecture, to increase the capabilities of automatic vessel movement control. Today, all automated systems already use the electronic principle of generating and transmitting signals from control devices (power plant telegraph, rudder, bow and stern thruster telegraphs and etc.) to executive devices, which greatly simplifies the integration of the on-board controller and the creation of a closed circuit of automatic control.

MC-DMD: A data-driven method for blood vessel enhancement in retinal images using morphological closing and dynamic mode decomposition

Detection of blood vessels in retinal images is an important step in any computer-aided pathological system for the early screening and detection of eye-related ailments such as retinal detachment, diabetic retinopathy, and macular degeneration. Propriety of the vessel enhancement process, as a pre-processing step, has been well established in medical corpus, for enhanced accuracy of vessel segmentation. Algorithms for retinal image extraction are still not qualitatively sufficient to be appropriate for diagnostics. This paper presents an effective and robust approach for retinal vessel enhancement that overcome prevailing deficiencies, using Morphological Closing based Dynamic Mode Decomposition (MC-DMD). The proffered algorithm exploits the power of mathematical morphology for the generation of input channel to the Dynamic Mode Decompostion (DMD) system, decomposing the vessel and non-vessel features of retinal images. We confirmed the effectiveness of the proposed enhancement method on three publicly available retinal image datasets: DRIVE, STARE and HRF, across nine existing vessel enhancement methods in terms of Receiver Operating Characteristic (ROC) curve and Area Under the ROC Curve (AUC). In addition, segmentation on final vessel map is performed and validated by enhanced performance in comparison with eight conventional vessel segmentation algorithms in terms of Sensitivity (SEN), Specificity (SP), Accuracy (ACC).

New String Deployment Concept Extends Operational Limits for Megareach Interventions

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 22577, “Extending the Operational Limits To Target Megareach Interventions With Coiled Tubing: A Study of the First 40,000-ft-Long CT String Deployment Using Uniquely Engineered Energy Transportation Solutions,” by Karan Kaul, Nicolas Dupouy, and Jose Jimenez, Halliburton, et al. The paper has not been peer reviewed. Copyright 2022 International Petroleum Technology Conference. Reproduced by permission. An operator requiring an offshore coiled tubing (CT) intervention into 40,000-ft-deep wells from artificial islands of the United Arab Emirates encountered challenging crane and transportation limitations to lift a 2⅜-in. CT reel weighing approximately 200,000 lbm. This, combined with a desire to improve operational efficiency in moving from well to well and eliminating large mechanical lifts, led to the design of a custom-engineered transportation solution for the large-diameter, heavy CT spool. Introduction CT and its associated setups are in high demand for wellbore intervention to perform operations such as valve or sleeve shifting, pinpoint stimulation with custom chemistry, milling, fishing, wellbore diagnostics using fiber optics, and drilling with different downhole tools. These tasks become even more challenging when difficulties associated with extended-reach maximum-reservoir-contact reservoirs are considered. While the term “extended-reach” refers to wells for which the measured depth (MD) is greater than twice the true vertical depth (TVD), the term “megareach” refers to wells for which the MD is greater than three times the TVD. A CT string is a continuous string of pipe manufactured from a specific grade of material determined by the downhole application for which it is intended. It is coiled over a drum (referred to in the paper as a spool) with more than 25 full layers around the bed wrap and has a high amount of energy stored in it because of the residual bending of the CT material. Although the string is secured at the end with an industry-specific clamp, close monitoring is required to avoid loosening from vibrations caused during transportation. After storing the CT pipe on the spool, the spool usually is shipped and transported from the shore jetty to the artificial island jetty using a conventional vessel. It is then offloaded, lifted, and secured onto a CT drive reel using a regular crane ready for wellsite operations (Fig. 1).

Warm-started semionline trajectory planner for ship’s automatic docking (berthing)

In the usual framework of control, a reference trajectory is needed as the set point for a feedback controller. This reference trajectory can be generated by solving a trajectory optimization problem. This problem is a continuous optimal control problem (OCP) that is transcribed into a finite-dimensional nonlinear optimization problem (NLP) and solved by SQP. For an underactuated conventional vessel, the mathematical model can be very intricate, hence the NLP itself. This causes significant computational time. This article demonstrates that the balance between the feasibility of the reference trajectory and the computational time can be achieved for an underactuated vessel in a disturbed and restricted environment. This is done by: (1) using an almost-globally optimal offline solution as a warm start in a semionline trajectory optimization to speed up the calculation, (2) including the prediction of wind dynamics, and (3) representing the ship as a rigid body and using a predefined boundary to generate the necessary spatial constraints via a point-in-polygon method that ensure a collision-free trajectory in a nonconvex region. Incorporation of these three things maintains a safe and dynamically feasible trajectory where the warm start gives a considerable computational speedup and better results than that without a warm start.

CFD Based Analysis of Resistance and Pitch Motion of Novel Flat Plate Panel Hull Vessel

This paper provides analysis regarding a phenomenal hull shape called flat panel concept, the flat panel hull is an axe bow vessel at the front part and semi trimaran at the stern part. This concept is for a small vessel such as fishing vessels, patrol vessels and prototypes have been built. Resistance and motion is important part of a vessel design, this paper compares a flat plate vessel with 282.56 ton displacement with a conventional vessel with the same displacement and same speed. The resistance comparison was conducted using Computational Fluid Dynamic (CFD) on each ship with a speed range of 5-10 knots of operational speed. The resistance shows that the flat panel vessel generates higher resistance compared to the conventional vessel where the difference varies from 8.388% to 19.954% depending on the speed. It also found that the pitch motion (Ry) of flat panel vessel is positive that indicates the bow draft is lower during the simulation in calm water. The highest value of pitch is 1.13 degrees measured at the amidships or zero point or -0.3 m at the bow. Two While the relative velocity or flow analysis indicates that flow of the flat panel vessel has enormous turbulence flow around the stern hull and smoother flow pattern at the bow, this may cause the increase of resistance and bow diving in calm water phenomena. However since the most accurate test is based on model test in hydrodynamic laboratory, it is recommended to conduct the comparison experiment in hydrodynamic laboratory.

Resistance Comparison of Flat Plate and Conventional Streamline Vessel

There was a phenomenal vessel which has unique hull shape, the shape of the hull is flattened not conventional streamlined as normal vessel. This phenomenal design is dedicated for small vessels such as fishing vessel, patrol vessel and a prototype has been built. This design raised a question regarding the resistance compared to conventional streamline vessel. This paper compares a flat plate vessel with 282.56 ton displacement with a conventional vessel with same displacement and same speed. The resistance comparison was conducted using Computational Fluid Dynamic (CFD) on each ship with speed range 5-10 knots of operational speed. The results of the CFD shows that the resistance of flat plate ship is higher compared to conventional vessel for 5 knots speed. The resistance value for 5 knots of flat plate vessel is 11,618 kN while the conventional vessel shape is 9.23kN. While for 10 knots speed, the flat plate vessel is also higher compared to conventional vessel with 54.53 kN for flat plate and 49.96 kN for conventional vessel.

A task-based analysis of the economic viability of low-manned and unmanned cargo ship concepts

While successful trials for autonomously navigating ships have been conducted, commercially available unmanned cargo ships are currently unavailable. However, there are many solutions available that will allow for low-manned ship concepts long before fully unmanned ships are possible. There are many drivers for low-manned and unmanned shipping, ranging from availability of workforce, to increased safety to economic. This article investigates the economic viability of several low-manned ship concepts as well as the unmanned ship concept for a short sea container vessel. The operating cost of these concepts are compared to those of a conventional vessel. That way, an assessment can be made on the economic viability. The results show that the low-manned concepts investigated in this article are worthwhile for the ship owner, as some savings can be achieved. The economic viability of the unmanned concept is dependent on the chosen type of propulsion.

Analysing the Performance of Ammonia Powertrains in the Marine Environment

This study develops system-level models of ammonia-fuelled powertrains that reflect the characteristics of four oceangoing vessels to evaluate the efficacy of ammonia as an alternative fuel in the marine environment. Relying on thermodynamics, heat transfer, and chemical engineering, the models adequately capture the behaviour of internal combustion engines, gas turbines, fuel processing equipment, and exhaust aftertreatment components. The performance of each vessel is evaluated by comparing its maximum range and cargo capacity to a conventional vessel. Results indicate that per unit output power, ammonia-fuelled internal combustion engines are more efficient, require less catalytic material, and have lower auxiliary power requirements than ammonia gas turbines. Most merchant vessels are strong candidates for ammonia fuelling if the operators can overcome capacity losses between 4% and 9%, assuming that the updated vessels retain the same range as a conventional vessel. The study also establishes that naval vessels are less likely to adopt ammonia powertrains without significant redesigns. Ammonia as an alternative fuel in the marine sector is a compelling option if the detailed component design continues to show that the concept is practically feasible. The present data and models can help in such feasibility studies for a range of vessels and propulsion technologies.

Optical Coherence Tomography Angiography-Derived Flux As a Measure of Physiological Changes in Retinal Capillary Blood Flow.

PurposeTo compare optical coherence tomography angiography (OCTA)–derived flux with conventional OCTA measures of retinal vascular density in assessment of physiological changes in retinal blood flow.MethodsHealthy subjects were recruited, and 3 × 3-mm2 fovea-centered scans were acquired using commercially available swept-source OCTA (SS-OCTA) while participants were breathing room air, 100% O2, or 5% CO2. Retinal perfusion was quantified using vessel area density (VAD) and vessel skeleton density (VSD), as well as novel measures of retinal perfusion, vessel area flux (VAF) and vessel skeleton flux (VSF). Flux is proportional to the number of red blood cells moving through a vessel segment per unit time. The percentage change in each measure was compared between the O2 and CO2 gas conditions for images of all vessels (arterioles, venules, and capillaries) and capillary-only images. Statistical significance was determined using paired t-tests and a linear mixed-effects model.ResultsEighty-four OCTA scans from 29 subjects were included (age, 45.9 ± 19.5 years; 14 male, 48.3%). In capillary-only images, the change under the CO2 condition was 168% greater in VAF than in VAD (P = 0.002) and 124% greater in VSF than in VSD (P = 0.004). Similarly, under the O2 condition, the change was 94% greater in VAF than in VAD (P = 0.004) and 57% greater in VSF than in VSD (P = 0.01). Flux measures showed significantly greater change in capillary-only images compared with all-vessels images.ConclusionsOCTA-derived flux measures quantify physiological changes in retinal blood flow at the capillary level with a greater effect size than conventional vessel density measures.Translational RelevanceOCTA-derived flux is a useful measure of subclinical changes in retinal capillary perfusion.

EGFR-mutant NSCLC presenting with stroke and massive systemic embolization as the first manifestation: case report

BackgroundPresentation with massive systemic embolization as the initial manifestation of occult malignancy is infrequent. The standard management of cancer-related arterial thromboembolism has not yet been established.Case presentationWe described a case of Trousseau’s syndrome resulting in acute ischemic stroke concomitant with multiple embolizations in the spleen and kidney during oral administration of dabigatran for pulmonary embolism preceding the diagnosis of a malignant tumor. A cancer-related hypercoagulable state was suspected because the patient was admitted to the neurology department due to acute ischemic stroke with three territory infarcts on diffusion-weighted imaging (DWI) in the absence of identifiable conventional risk factors and brain vessel narrowing. The patient was subsequently diagnosed with epidermal growth factor receptor (EGFR) mutation–positive non-small-cell lung cancer (NSCLC) (stage IV) with pleural metastasis. Administration of low-molecular-weight heparin followed by long-term dabigatran under effective cancer therapy comprising gefitinib and subsequent chemotherapy did not cause stroke relapse during the 1-year follow-up.ConclusionsThis case suggests that cancer-related hypercoagulability should be considered an important etiology for stroke patients who develop unexplained disseminated acute cerebral infarction without conventional stroke risk factors, especially concomitant with multiple organ embolization. Novel oral anticoagulants may be an alternative therapy for the long-term management of cancer-related arterial thromboembolism under effective cancer therapy.

Development and Real-Time Performance Evaluation of Energy Management Strategy for a Dynamic Positioning Hybrid Electric Marine Vessel

Hybridisation of energy sources in marine vessels has been recognized as one of the feasible solutions to improve fuel economy and achieve global emission reduction targets in the maritime sector. However, the overall performance of a hybrid vessel system is strongly dependent on the efficiency of the energy management system (EMS) that regulates the power-flow amongst the propulsion sources and the energy storage system (ESS). This study develops a simple but production-feasible and efficient EMS for a dynamic positioning (DP) hybrid electric marine vessel (HEMV) and real-time experimental evaluation within a hardware-in-the-loop (HIL) simulation environment. To support the development and evaluation, map-based performance models of HEMVs’ key components are developed. Control logics that underpin the EMS are then designed and verified. Real-time performance evaluation to assess the performance and applicability of the proposed EMS is conducted, showing the improvement over those of the conventional control strategies. The comparison using key performance indicators (KPIs) demonstrates that the proposed EMS could achieve up to 4.8% fuel saving per voyage, while the overall system performance remains unchanged as compared to that of the conventional vessel.

Preclinical development of a novel coaptive vessel sealing device for liver resection

Presenter: Lucas Thornblade MD, MPH | City of Hope Cancer Center Background: The safety of liver resection has increased dramatically, in great part due to advances in devices for parenchymal transection. We identified five limitations to existing vessel sealer technology: bulky jaws, short seal-zones, propensity for tissue shearing, tissue-char fouling, and the cost of fully disposable units. We sought to develop an affordable sealing device platform that could safely reduce the time required for open liver resection. Methods: We partnered with engineers to develop a radiofrequency (RF) powered coaptive sealing device with five features unique among existing vessel sealers. First, the device achieves a 6.5cm long seal zone, allowing faster parenchymal transection (Figure panel A). Second, lower-profile jaws reduce tissue tearing upon insertion into liver parenchyma. Third a spring-loaded hinge provides parallel apposition and reduces tissue shear. Fourth, the device applies saline to the sealing surface which reduces fouling upon repeated firings. And lastly, the reusable handle and low-cost RF generator facilitates an affordable alternative to conventional vessel sealers. The device was tested on 12 partial hepatectomies in six live canine models in compliance with 510(k) processes in an accredited large animal lab. Necropsy was performed 7-9 days postoperatively by a veterinary pathologist. Results: All subjects tolerated liver resection with minimal blood loss ( < 20cc). Figure panel B demonstrates a completed partial hepatectomy of the canine liver. Transaminases peaked by postoperative day four (mean ALT 194 U/L). At necropsy, no hematoma or bile collections were found. Novel design elements were registered with the U.S. Patent Office. Conclusion: By careful study of the limitations of existing designs, surgeons have a unique opportunity to impact changes in future surgical technology. Further work includes design refinement, regulatory overview for testing in humans, and partnership with industry.

CarbonNet progress towards a declaration of identified storage formation at the Pelican site with a new high-resolution 3D seismic dataset

The CarbonNet project is making the first ever application for a ‘declaration of an identified greenhouse gas storage formation’ (similar to a petroleum location) under the Offshore Petroleum and Greenhouse Gas Storage Act. Unlike a petroleum location, however, there is no ‘discovery’ involved in the application. Instead, a detailed technical assessment is required of the geological suitability for successful long-term storage of CO2. The key challenges to achieving a successful application relate to addressing ‘fundamental suitability determinants’ under the act and regulations. At Pelican (Gippsland Basin), a new high-resolution 3D seismic survey and over 10 nearby petroleum wells (and over 1500 basinal wells) supplement a crestal well drilled in 1967 that proved the seal and reservoir stratigraphy. The GCN18A 3D marine seismic survey has the highest spatial and frequency resolution to date in the Gippsland Basin. The survey was acquired in water depths from 15 to 35 m with a conventional eight-streamer seismic vessel, aided by LiDAR bathymetry. The 12.5 m bin size and pre-stack depth migration with multiple tomographic velocity iterations have produced an unprecedented high-quality image of the Latrobe Group reservoirs and sealing units. The 3D seismic data provides excellent structural definition of the Pelican Anticline, and the overlying Golden Beach-1A gas pool is excellent. Depositional detail of reservoir-seal pairs within the Latrobe Group has been resolved, allowing a confident assessment of petroleum gas in place and CO2 storage opportunities. The CarbonNet project is progressing with a low-risk storage concept at intra-formational level, as proven by trapped pools at nearby oil and gas fields. Laterally extensive intra-formational shales provide seals across the entire structure, providing pressure and fluid separation between the overlying shallow hydrocarbon gas pool and the deeper CO2 storage opportunity. CarbonNet is assessing this storage opportunity and progressing towards a ‘declaration of an identified greenhouse gas storage formation’.

Experimental Model to Assess the Efficacy and Safety of Vessel Sealing Devices in By-pass Surgery

Introduction - Energy sealing devices achieve hemostasis of blood vessels through sequential coagulation and tissue transection. The most frequently used ones are: Electrothermal Bipolar Tissue Sealing System (EB) and Harmonic Scalpel (HS). Both methods are based on denaturation and fusion of proteins of the vessel wall (mainly collagen and elastin) by controlled delivery of energy: electrothermal by radiofrequency and impedance feed-back (EB) or high frequency ultrasound vibration (HS). Although its use has been widely spread in multiple surgical fields, most vascular surgeons are not confident enough about its safety for sealing collaterals of autologous grafts during by-pass surgery. The aim of this study was to compare the efficacy and safety of EB and HS with conventional vessel ligation of saphenous vein (SV) collaterals in an experimental model. Methods - Twenty-five fragments of SV were extracted from cadaver donor (n=6) or from residual fragments during amputation or lower limb revascularization procedures (n=19). To simulate physiological conditions, a pulsatile flow circuit was performed with a roller pump, and intravascular pressure was recorded by a pressure gauge and a pressure monitor. In each fragment, two venous collateral seals were made, one by conventional ligation with 3/0 silk (control) and the other one with EB (N= 13) or HS (N= 12), after sequentially consecutive assignment. Each venous fragment was then incorporated into the pulsatile flow circuit, and the pressure was progressively increased until 300 mmHg (supraphysiological) was reached, or until sealing breakage occurred. Collateral vein diameter, burst pressures, and leakage points were recorded. A histological study with hematoxylin-eosin and Masson's trichrome stain was also performed for each energy-sealing device. A descriptive analysis and analytical statistical tests (U-Mann Whitney, Chi-square) were performed. Results - The mean diameter of the venous collaterals was 2.42±0.7mm and 2.38±0.6 mm, p = NS, for EB and HS, respectively. The mean burst pressure was slightly higher for EB than for HS (788.9±455.0 mmHg vs 602.5±363.1 mmHg, p = 0.268). In only one case (HS) the outbreak occurred in the sealing zone at pressures below 300 mmHg. In all cases for EB, the rupture occurred at supraphysiological pressures.The leakage point for HS occurred in sealed collateral in all cases (12/12). For EB, the leakage point occurred in its sealing zone in 8 of 13 fragments, and in the conventional ligation (control), in the remaining 5 fragments (p=0.016). The histological study showed no differences in the tissues coagulated by both devices. Conclusion - Vessel sealing devices are as effective and safe for the hemostasis of saphenous vein collaterals as conventional ligation. These devices may be useful given their fast sealing time and easy handling during surgical venous graft preparation for lower limb revascularization. In our study, the EB showed greater strength in the sealing of saphenous vein collaterals compared to HS, however the outbreak occurred at supraphysiological pressures, so this fact may not have clinical relevance. References-Toishi M, Yoshida K, Agatsuma H et al. Usefulness of vessel-sealing devices for <7mm diameter vessels: a randomized controlled trial for human thoracoscopic lobectomy in primary lung cancer. Interactive CardioVascular and Thoracic Surgery, 2014 (19): 448-55.-Rajbabu K, Baber NJ, Chol W et al. To knot or not to knot? Sutureless haemostasis compared to the surgeons's knot. Ann R Coll Surg Engl, 2007; 89: 359-62.-Lamberton GR, Hsi R, Jin D et al. Prospective comparision of four laparoscopic vessel ligation devices. Journal of endourology, 2008; 22: 1-6.-Lacin T, Batirel HF, Ozer K et al. Safety of a thermal vessel sealer on main pulmonary vessels. European Journal of Cardio-thoracic Surgery, 2007; 31: 482-85.

Comparative Study Between Ligasure Versus Conventional Vessel Ligation in Thyroidectomy

Comparative Study Between Ligasure Versus Conventional Vessel Ligation in Thyroidectomy