Optimal Device Placement Research Articles

Vascular access device selection: Optimizing patient outcomes - Part 1.

A systematic evaluation of vascular access device (VAD) selection incorporates patient, device, and infusate characteristics to ensure optimal device placement. This article explores VAD selection from the perspective of vessel health and preservation and describes VAD selection options and indications, VAD-related complications, and strategies to reduce those complications.

Abstract 12297: Kissing Left Atrial Appendage Closure Devices for Peri-Device Leak

Introduction: Left atrial appendage closure (LAAC) therapy is approved for stroke prevention in nonvalvular atrial fibrillation (AF) for patients intolerant in long term oral anticoagulation (OAC). Peri-device leak (PDL) is the achilles heel to optimal LAAC and increases stroke risk. Here, we describe the novel use of a second LAAC device for closure of a large PDL in a bilobar appendage. Case: A 66-year-old male with a history of nonvalvular AF with recurrent bleeding on OAC with Watchman 2.5 implant six years prior, presented to our facility for a repeat AF ablation. Pre-procedural imaging showed a PDL of 12 mm with an uncovered posterior lobe, with the Watchman 2.5 covering only the anterior lobe of the appendage. The PDL was closed with a 20 mm Amulet device delivered through a steerable sheath abutting the existing Watchman 2.5 device. The steerability of the sheath allowed for optimal placement of the Amulet device to allow for complete closure. Patient was discharged home on six weeks of dual antiplatelet therapy. Discussion: In our case, a second LAAC device was chosen due to the large size of the PDL. Smaller leaks can be closed using endovascular coils and/or occluder plugs. Larger leaks require additional consideration for closure strategies such as a second LAAC device Conclusions: Our case is the first reported case utilizing a second LAAC device for PDL closure alongside the first device. Steerability of the new Amulet sheath allowed for optimal device placement for complete closure. Additional research is needed on how PDL’s should be addressed for optimal LAAC. Figure 1: Imaging showing PDL into uncovered posterior lobe Figure 2: Complete LAAC with kissing Watchman 2.5 and Amulet

Personalized Radiation Attenuating Materials for Gastrointestinal Mucosal Protection.

Cancer patients undergoing therapeutic radiation routinely develop injury of the adjacent gastrointestinal (GI) tract mucosa due to treatment. To reduce radiation dose to critical GI structures including the rectum and oral mucosa, 3D‐printed GI radioprotective devices composed of high‐Z materials are generated from patient CT scans. In a radiation proctitis rat model, a significant reduction in crypt injury is demonstrated with the device compared to without (p < 0.0087). Optimal device placement for radiation attenuation is further confirmed in a swine model. Dosimetric modeling in oral cavity cancer patients demonstrates a 30% radiation dose reduction to the normal buccal mucosa and a 15.2% dose reduction in the rectum for prostate cancer patients with the radioprotectant material in place compared to without. Finally, it is found that the rectal radioprotectant device is more cost‐effective compared to a hydrogel rectal spacer. Taken together, these data suggest that personalized radioprotectant devices may be used to reduce GI tissue injury in cancer patients undergoing therapeutic radiation.

Swarm intelligence‐based optimal device deployment in heterogeneous Internet of Things networks for wind farm application

SummaryInternet of Things (IoT) is becoming a suitable surveillance system in modern power grid, right from power generation to distribution. In the case of wind power generation application, the entire wind farm is considered completely monitored using edge devices known as IoT devices. Device deployment is a major obstacle that can be addressed for this application as unfair device deployment can lead to connectivity issue. This study has two main objectives. The first objective is to determine the optimal number of IoT devices that need to be place in the potential key elements of the wind turbines/targets for coverage assurance. The second objective is to determine the optimal number of relay devices. Spacing wind turbines several hundred meters apart brings the connectivity as a second critical issue, which can be handling by placing optimal number of relay devices. Hence, the focus of this study is to address connected target coverage problem in optimal device placement of heterogeneous IoT network for wind farm monitoring. This paper discusses in detail the swarm intelligence technique known as particle swarm optimization (PSO) to solve the connectivity issue and to minimize the cost of devices deployment. Additionally, a hybrid swarm intelligence model called hybrid PSO‐ACO (HPACO) algorithm is proposed. The main goal of this hybrid model is to reduce the number of relay devices, minimize deployment cost, and to improve network connectivity. The performance of both PSO and HPACO algorithms are validating by comparing the extensive simulation results with ant colony optimizations (ACO) algorithm and other approximation algorithm.

Interval method based optimal planning of multi-energy microgrid with uncertain renewable generation and demand

Creating an optimal design for multi-energy microgrids is a challenge owing to the complicated energy flows existing between sources and demands. In addition, the uncertainties of microgrids, in particular, the stochastic problem of wind, solar, and energy demands, are difficult to describe and overcome. To address these problems, this study proposes an interval method based planning model for MEMGs that determines the device to be installed, the optimal device capacity, the optimal device placement, and the associated optimal operation of multiple energy types with considering uncertainties, the electrical power flow and heat flow equations was also included in our model. These uncertainties of renewable energy and demand are described as intervals, and based on the interval linear programming theory, the corresponding uncertain constraints could be converted to deterministic ones. The developed model is formulated as mixed-integer linear programming, which renders the design model easy to understand and compute. The feasibility and superiority of the model are verified via case studies and analyses, although the results of proposed model turn to be more conservative which means low efficiency in economy, the planning scheme is able to adapt to different uncertain scenarios and maintain the reliability of operation, which means that the robustness of the result were enhanced.

Adjustment of genetic algorithm parameters for solving the problem of topology optimization of the sensory network

The paper is devoted to the optimal placement of devices within a wireless sensor network. Modern requirements to ensure public safety in buildings with a complex structure imply the existence of systems that can detect and position emergency situation, inform rescue and tenants about the status and help them to either evacuate or eliminate the danger. Nowadays the main approach to create indoor emergency system is based on wireless sensor network. The network is built with a big number of usually battery-operating devices, each consists of a sensors set for hazard detection, and radio frequency module for communication. To evaluate the state of indoor environment different sensors can be used, such as temperature, humidity, light, flame, smoke, gas, etc. The problem of optimizing the network topology as a covering problem is formulated. A set of points in the area that is not covered by circles, a set of points belonging to the region and the intersection of two or more circles of coverage, set of points that do not belong to the area need to be minimized. To ensure fault tolerance of the wireless sensor network, it is necessary to allow the connection of each sensor with at least two routers, in case one of the routers is accidentally switched off, and also it is necessary to ensure connection of the router with at least one router. To take into account these additional conditions, the method of penalty functions is used. The genetic algorithm for solving the problem is used. The main genetic operators are adapted to the problem of designing the topology of wireless sensor networks. A computa-tional experiment was carried out, during which the optimal population size was estab-lished; the procedure of homogeneous crossing, procedure of tournament selection is chosen; procedure of homogeneous mutation. As a criterion for stopping the genetic algorithm, the stagnation of the results on the iterations of the algorithm is chosen.

A Methodology to Study the Effect of Smoke and Fire on Indoor RF Propagation

An indoor wireless network comprises of multiple devices connected wirelessly in a small geographical area, giving mobility to the connected devices. RF signal associated with wireless networks suffers from many propagation losses. It becomes essential to estimate losses at different locations, in the intended coverage area, to attain the desired performance seamlessly. It helps in the optimal device placement in the wireless networks. In the application, in addition to the propagation losses, there is a need to estimate the loss induced by the presence of smoke and fire, individually, in an indoor environment. This paper first deals with the design of a heatmap generating tool, in MATLAB, which gives the approximate signal strength at different locations on a given floor for a given transmitter. Then the paper discusses the formation of plasma in fast flaming fires and presents the path loss due to it. This path loss is incorporated in the heatmap generating tool and a heatmap is generated for our office ground floor for the case of a flaming fire. The paper also describes a testbed, setup in our office premises, to study the scattering loss caused by smoke particles.

Application of cellular automatons and ant algorithms in avionics

The paper considers two algorithms for searching quasi-optimal solutions of discrete optimization problems with regard to the tasks of avionics placing. The first one solves the problem of optimal placement of devices by installation locations, the second one is for the problem of finding the shortest route between devices. Solutions are constructed using a cellular automaton and the ant colony algorithm.

Sometimes they come back

: An increasing number of patients are being evaluated for percutaneous patent foramen ovale (PFO) closure to prevent recurrent cerebrovascular events, but debate still exists on therapeutic indications and off-label closure device implantation. Pulmonary arteriovenous fistulas (PAVFs) are a rare and heterogeneous malformation prevalently associated with Rendu-Osler-Weber syndrome, and may mimic PFO right-to-left shunt (RLS), leading to unnecessary interventions and in some cases to relapses. Residual shunt is increasingly being observed both after PFO closure and PAVF embolization, even at long-term follow-up, with unclear clinical relevance. This instrumental and possibly therapeutic failure could lie in the presence of pulmonary microfistulas, either pre-existing or following the intervention. Hence, if RLS persists after optimal device placement and reasonable endothelialization time, the presence of a PAVF should be assumed and investigated; if RLS recurs after previous, negative echocontrast studies, presence of device-related complications or pulmonary microfistulas should be taken into consideration.

Virtual flow-diverter treatment planning: The effect of device placement on bifurcation aneurysm haemodynamics.

Bifurcation aneurysms account for a large fraction of cerebral aneurysms and often present morphologies that render traditional endovascular treatments, such as coiling, challenging and problematic. Flow-diverter stents offer a potentially elegant treatment option for such aneurysms, but clinical use of these devices remains controversial. Specifically, the deployment of a flow-diverter device in a bifurcation entails jailing one or more potentially vital vessels with a low-porosity mesh designed to restrict the flow. When multiple device placement configurations exist, the most appropriate clinical decision becomes increasingly opaque. In this study, three bifurcation aneurysm geometries were virtually treated by flow-diverter device. Each aneurysm was selected to offer two possible device deployment positions. Flow-diverters similar to commercially available designs were deployed with a fast-deployment algorithm before transient and steady state computational fluid dynamics simulations were performed. Reductions in aneurysm inflow, mean wall shear stress and maximum wall shear stress, all factors often linked with aneurysm treatment outcome, were compared for different device configurations in each aneurysm. In each of the three aneurysms modelled, a particular preferential device placement was shown to offer superior performance with the greatest reduction in the flow metrics considered. In all the three aneurysm geometries, substantial variations in inflow reduction (up to 25.3%), mean wall shear stress reduction (up to 14.6%) and maximum wall shear stress reduction (up to 12.1%) were seen, which were all attributed to device placement alone. Optimal device placement was found to be non-trivial and highly aneurysm specific; in only one-third of the simulated geometries, the best overall performance was achieved by deploying a device in the daughter vessel with the highest flow rate. Good correspondence was seen between transient results and steady state computations that offered a significant reduction in simulation run time. If accurate steady state computations are combined with the fast-deployment algorithm used, the modest run time and corresponding hardware make a virtual treatment pipeline in the clinical setting a meaningful possibility.

Evaluating the quality of implantation of percutaneous ventricular restoration device (Parachute®) by cardiac computed tomography.

The Parachute is a novel percutaneously implanted ventricular partitioning device (VPD) that has emerged as a safe and feasible treatment option for patients with heart failure following anterior wall myocardial infarction. VPD efficacy is likely dependent on optimal device placement, but to date there are no published data examining the effect of device positioning on patient outcomes. We retrospectively identified 32 patients successfully implanted with the Parachute device, all of whom underwent cardiac computed tomography (CCT) at baseline and after 6 months of follow-up. Patients were divided into two groups based on self-reported improvement in New York Heart Association (NYHA) functional class: "not improved NYHA" (n = 12) and "improved NYHA" (n = 20). There were significant differences between both groups with regard to device positioning on follow-up CCT. Compared to patients with "improved NYHA," patients with "not improved NYHA" had longer distances from device foot to left ventricular apex (8.0 ± 4.9 vs. 2.9 ± 4.6 mm; P = 0.01), and higher lateral angles (18.0 ± 14 vs. 9.1 ± 6.8 degrees; P = 0.02), respectively. There was no significant difference between the two groups in landing zone (45.4 ± 7. vs. 45.1 ± 6.9 mm; P = 0.92) and inferior angle (14.0 ± 11.9 vs. 14.3 ± 10.1 degrees; P = 0.95). There was a numerically larger malapposition area in the "not improved NYHA" group (5.1 ± 4.5 vs. 3.2 ± 2.2 cm2; P = 0.12). Quality of Parachute implant impacted clinical outcome, these findings should be applied prospectively in helping operators to achieve optimal implant. © 2016 Wiley Periodicals, Inc.

Comparison of BBO, WIPSO & PSO Techniques for the Optimal Placement of FACTS Devices to Enhance System Security

Nowadays power systems are heavily loaded and are being operated in ways not originally envisioned. Flexible AC Transmission System (FACTS) devices play a vital role in improving the static as well as dynamic performance of the power systems. FACTS devices are based on solid-state control and so the control actions at far higher speed is possible. However the location and rating of the FACTS devices play a major role in deciding the extent to which the objective of improving the system performance is achieved in a cost effective manner. In this work an objective function comprising of cost, line loadings and load voltage deviations is proposed to tap maximum benefits out of their installation and the weights assigned to them decide their relative importance. FACTS devices such as Thyristor Controlled Series Compensator (TCSC) and Static VAR Compensator (SVC) are considered. The optimization is carried out considering four parameters namely the number of FACTS device, location, type and rating of the device. In this work three cases (only TCSC, only SVC, TCSC & SVC) are considered forthe optimal placement of the devices, using PSO, WIPSO and BBO techniques.

Intracardiac echocardiography-guided transcatheter closure of secundum atrial septal defect: A new efficient device selection method

ObjectivesWe assessed the use of intracardiac echocardiography (ICE) as the primary means for both selection of the Amplatzer Septal Occluder (ASO) and the guidance of transcatheter closure of secundum atrial septal defects (ASDs). BackgroundThe standard method for transcatheter closure of ASDs requires balloon-sizing maneuver and transesophageal echocardiographic (TEE) monitoring. The role of ICE during transcatheter closure of ASDs has not yet been established. MethodsIn 91 patients with ASDs, two standardized orthogonal sections were used to obtain ICE-derived measurements of the fossa ovalis and to assess optimal device deployment: the transverse section on the aortic valve plane, and the longitudinal section on the four-chamber plane. ResultsIn all patients, ICE planes were identified with excellent resolution, providing proper measurements of the fossa ovalis, from which to derive geometric assumptions for the selection of an appropriately sized device. The ASO waist diameter was chosen on the basis of the rvalue (r= c2+ p2, where ris the radius of an ideal circle that intersects the elliptical fossa ovalis in its semi-latus rectum, cis the foci half-distance of the fossa ovalis, and pis its semi-latus rectum). During the procedure, the four-chamber plane allowed us to obtain easily interpretable images of all stages of device deployment. Midterm complete occlusion rate was 97.8%. No ICE-related complications occurred. ConclusionsThe ICE evaluation of ASDs allows quantitative and qualitative information for both proper ASO selection and optimal device placement, thus eliminating the cumbersome balloon-sizing maneuver and the need for general anesthesia during TEE monitoring.

Role of intracardiac echocardiography in atrial septal abnormalities.

The purpose of this review is to outline the feasibility of performing a comprehensive atrial septal examination from the internal confine of the right atrium and to evaluate the advantages resulting by intracardiac echocardiography (ICE) evaluation of atrial septal morphology as well as pathophysiology. In this setting, ICE indications have not yet been established because ICE is a relatively new technique that is still evolving. Notwithstanding, during catheter-based secundum atrial septal defect and patent foramen ovale closure, ICE seems useful for diagnosing cardiac abnormalities instantly, guiding and monitoring all stages of the procedures, and assessing proper selection and optimal device placement. Moreover, ICE provides solid anatomical criteria to diagnose fenestrated atrial septal aneurysm, interatrial communications such as ostium primum and sinus venosus defects, partial anomalous pulmonary venous connection, and lipomatous hypertrophy of atrial septum.