Shortwave Infrared Imaging of a Quantum Dot-Based Magnetic Guidewire Toward Non-Fluoroscopic Peripheral Vascular Interventions.

Peripheral vascular interventions (PVIs) offer several benefits to patients with lower extremity arterial diseases, including reduced pain, simpler anesthesia, and shorter recovery time, compared to open surgery. However, to monitor the endovascular tools inside the body, PVIs are conducted under X-ray fluoroscopy, which poses serious long-term health risks to physicians and patients. Shortwave infrared (SWIR) imaging of quantum dots (QDs) has shown great potential in bioimaging due to the non-ionizing penetration of SWIR light through tissues. In this paper, a QD-based magnetic guidewire and its system is introduced that allows X-ray-free detection under SWIR imaging and precise steering via magnetic manipulation. The QD magnetic guidewire contains a flexible silicone tube encapsulating a QD polydimethylsiloxane (PDMS) composite, where HgCdSe/HgS/CdS/CdZnS/ZnS/SiO2 core/multi-shell QDs are dispersed in the PDMS matrix for SWIR imaging upon near-infrared excitation, as well as a permanent magnet for magnetic steering. The SWIR penetration of the QD magnetic guidewire is investigated within an artificial tissue model (1% Intralipid) and explore the potential for non-fluoroscopic PVIs within a vascular phantom model. The QD magnetic guidewire is biocompatible in its entirety, with excellent resistance to photobleaching and chemical alteration, which is a promising sign for its future clinical implementation.

Large-bore Chest Tube Insertion: Seldinger Technique over Two Guidewires.

Purpose: Large-bore chest tube insertion is commonly performed using the trocar technique and blunt dissection; however, large-bore chest tube can cause severe visceral injury due to penetration, which is a life-threatening complication. Conversely, small-bore chest tubes can be safely inserted using the Seldinger technique; however, small-bore chest tubes are prone to blockage, especially in empyema cases. Therefore, this study aimed to demonstrate large-bore chest tube insertion using the Seldinger technique over two guidewires following image-guided puncture. Material and Methods: We started performing large-bore chest tube insertion using the Seldinger technique over two guidewires following image-guided puncture in February 2022. Demographic data and procedural details, such as chest tube size, dilator size, procedure time, and type of image-guided puncture, of patients who underwent this procedure between February 2022 and March 2023 were retrospectively reviewed. Technical success was defined as the successful drainage of the pleural cavity. Results: This method was used for performing ten procedures in nine patients who presented with empyema, pneumothorax, and pulmonary fistula. The insertion of a large-bore chest tube with a size ranging from 18- to 24-French was successfully performed in all cases without any complications. The median procedure time was 17.5 (first quartile-third quartile, 13.5-28.0) min. Conclusions: Large-bore chest tube insertion using the Seldinger technique over two guidewires may be used as an alternative to conventional methods.

Modeling and experimental study of the intervention forces between the guidewire and blood vessels.

A profound investigation of the interaction mechanics between blood vessels and guidewires is necessary to achieve safe intervention. An interactive force model between guidewires and blood vessels is established based on cardiovascular fluid dynamics theory and contact mechanics, considering two intervention phases (straight intervention and contact intervention at a corner named "J-vessel"). The contributing factors of the force model, including intervention conditions, guidewire characteristics, and intravascular environment, are analyzed. A series of experiments were performed to validate the availability of the interactive force model and explore the effects of influential factors on intervention force. The intervention force data were collected using a 2-DOF mechanical testing system instrumented with a force sensor. The guidewire diameter and material were found to significantly impact the intervention force. Additionally, the intervention force was influenced by factors such as blood viscosity, blood vessel wall thickness, blood flow velocity, as well as the interventional velocity and interventional mode. The experiment of the intervention in a coronary artery physical vascular model confirms the practicality validation of the predicted force model and can provide an optimized interventional strategy for vascular interventional surgery. The enhanced intervention strategy has resulted in a considerable reduction of approximately 21.97 % in the force exerted on blood vessels, effectively minimizing the potential for complications associated with the interventional surgery.

Right Heart Catheterization: An Antecubital Vein Approach to Reduce Fluoroscopy Time, Radiation Dose, and Guidewires Need.

Antecubital access for right heart catheterization (RHC) is a widespread technique, even though there is a need to clarify if there are differences and significant advantages compared to proximal vein access. To pursue this issue, we retrospectively identified patients who underwent RHC in our clinic over a 7 year period (between January 2015 and December 2022). We revised demographic, anthropometric, and procedural data, including the fluoroscopy time, the radiation exposure, and the use of guidewires. The presence of any complications was also assessed. In patients with antecubital access, the fluoroscopy time and the radiation exposure were lower compared to proximal vein access (6 vs. 3 min, mean difference of 2 min, CI 95% 1-4 min, p < 0.001 and 61 vs. 30 cGy/m2, mean difference 64 cGy/m2, CI 95% 50-77, p < 0.001). The number of patients requiring the use of at least one guidewire was lower in the group undergoing RHC through antecubital access compared to proximal vein access (55% vs. 43%, p = 0.01). The feasibility was optimal, as just 0.9% of procedures switched from antecubital to femoral access, with a negligible rate of complications. The choice of the antecubital site exhibits advantages, e.g., a shorter fluoroscopy time, a reduced radiation dose, and a lower average number of guidewires used compared to proximal vein access.

Best crossing of peripheral chronic total occlusions.

Together with colleagues from different disciplines, including cardiologists, interventional radiologists and vascular surgeons, committee members of the of the German Society of Angiology (Deutsche Gesellschaft für Angiologie [DGA]), developed a novel algorithm for the endovascular treatment of peripheral chronic total occlusive lesions (CTOs). Our aim is to improve patient and limb related outcomes, by increasing the success rate of endovascular procedures. This can be achieved by adherence to the proposed crossing algorithm, aiding the standardization of endovascular procedures. The following steps are proposed: (i) APPLY Duplex sonography and if required 3D techniques such as computed tomography or magnetic resonance angiography. This will help you to select the optimal access site. (ii) EVALUATE the CTO cap morphology and distal vessel refilling sites during diagnostic angiography, which are potential targets for a retrograde access. (iii) START with antegrade wiring strategies including guidewire (GW) and support catheter technology. Use GW escalation strategies to penetrate the proximal cap of the CTO, which may usually be fibrotic and calcified. (iv) STOP the antegrade attempt depending on patient specific parameters and the presence of retrograde options, as evaluated by pre-procedural imaging and during angiography. (v) In case of FAILURE, consider advanced bidirectional techniques and reentry devices. (vi) In case of SUCCESS, externalize the GW and treat the CTO. Manage the retrograde access at the end of the endovascular procedure. (vii) STOP the procedure if no progress can be obtained within 3 hours, in case of specific complications or when reaching maximum contrast administration based on individual patient's renal function. Consider radiation exposure both for patients and operators. In this manuscript we systematically follow and explain each of the steps (i)-(vi) based on practical examples from our daily routine. We strongly believe that the integration of this algorithm in the daily practice of endovascular specialists, can improve vessel and patient specific outcomes.

Experimental Protocol and Phantom Design and Development for Performance Characterization of Conventional Devices for Peripheral Vascular Interventions.

Conventional catheter-based interventions for treating peripheral artery disease suffer high failure and complication rates. The mechanical interactions with the anatomy constrain catheter controllability, while their length and flexibility limit their pushability. Also, the 2D X-ray fluoroscopy guiding these procedures fails to provide sufficient feedback about the device location relative to the anatomy. Our study aims to quantify the performance of conventional non-steerable (NS) and steerable (S) catheters in phantom and ex vivo experiments. In a 10 mm diameter, 30 cm long artery phantom model, with four operators, we evaluated the success rate and crossing time in accessing 1.25 mm target channels, the accessible workspace, and the force delivered through each catheter. For clinical relevance, we evaluated the success rate and crossing time in crossing ex vivo chronic total occlusions. For the S and NS catheters, respectively, users successfully accessed 69 and 31% of the targets, 68 and 45% of the cross-sectional area, and could deliver 14.2 and 10.2 g of mean force. Using a NS catheter, users crossed 0.0 and 9.5% of the fixed and fresh lesions, respectively. Overall, we quantified the limitations of conventional catheters (navigation, reachable workspace, and pushability) for peripheral interventions; this can serve as a basis for comparison with other devices.

Crossing Algorithm for Infrainguinal Chronic Total Occlusions: An Interdisciplinary Expert Opinion Statement.

A crossing algorithm was developed for the endovascular treatment of peripheral chronic total occlusive lesions (CTOs) to educate, guide, and appropriately influence clinical practice aiming at harmonization and standardization of endovascular procedures. The following steps are proposed: One, duplex sonography and if required computed tomography or magnetic resonance angiography for the selection of the optimal access site. Two, angiographic evaluation of the proximal/distal cap morphology, presence of collaterals at the origin of the proximal cap and at the distal vessel refilling site. In addition, evaluation of distal vessels, including their diameters and quality, and the presence of calcification or stents within the occlusion zone. Three, antegrade wiring strategies, guidewire (GW) and support catheter technology, as well as GW escalation strategies. Stop the antegrade attempt depending on clinical indication for peripheral artery disease treatment and the presence of retrograde options. Four, retrograde access site, support catheter, or sheath insertion and wiring technology from distally. Five, considering strategy change when progress cannot by achieved, using advanced bidirectional techniques and re-entry devices. Six, in case of successful GW passage from retrograde, GW externalization and treatment from antegrade. Management of the retrograde access by internal or external hemostasis at the end of the procedure. Alternatively, stop the procedure if no progress can be obtained within 3 hours or in case of specific complications. By establishing the algorithm in the daily routine of endovascular specialists, improvements in vessel- and patient-specific outcomes are anticipated. In addition, future research, and continuous collaboration between experts is warranted.

The Supportive Guidewire Paradox: How Extra Support Guidewires May Hinder Equipment Delivery Through Tortuous and Calcified Coronary Lesions.

Percutaneous coronary intervention of heavily calcified coronary vessels can be challenging due to difficult equipment delivery and suboptimal stent expansion, leading to worse clinical outcomes. Supportive guidewires are designed to facilitate equipment delivery. We present two cases of heavily calcified and tortuous coronary lesions in which use of support guidewires hindered balloon and stent delivery, possibly by increasing friction between equipment and the wall of the coronary vessel. Equipment delivery was achieved using less supportive workhorse guidewires.

Innovative Method to Retrieve Misplaced Guidewires Using Guidewires and Balloons.

Central venous catheters (CVC) are placed commonly for long-term access in critically ill patients for injecting medicines, including chemotherapy in oncology patients, and for total parenteral nutrition. We herein describe innovative method of snaring two misplaced guidewires using balloons and guidewires.

Risk Assessment and Regulatory Exploration of the Lubrication Coating on Intravascular Medical Devices.

Lubricious polymer coatings are increasingly used on intravascular devices to facilitate application processes. Although increasing reports about the detachment and subsequent embolism of polymer particles, this iatrogenic polymer embolism has not been paid enough clinical attention for many years. This article reviews the hazard of coating separation and the difficulty to find it. Furthermore, this proposes the scientific evaluation concept and regulatory exploration to solve the problems.

An Electromagnetically Controllable Microrobotic Interventional System for Targeted, Real-Time Cardiovascular Intervention.

Robotic magnetic manipulation systems offer a wide range of potential benefits in medical fields, such as precise and selective manipulation of magnetically responsive instruments in difficult-to-reach vessels and tissues. However, more preclinical/clinical studies are necessary before robotic magnetic interventional systems can be widely adopted. In this study, a clinically translatable, electromagnetically controllable microrobotic interventional system (ECMIS) that assists a physician in remotely manipulating and controlling microdiameter guidewires in real time, is reported. The ECMIS comprises a microrobotic guidewire capable of active magnetic steering under low-strength magnetic fields, a human-scale electromagnetic actuation (EMA) system, a biplane X-ray imaging system, and a remote guidewire/catheter advancer unit. The proposed ECMIS demonstrates targeted real-time cardiovascular interventions in vascular phantoms through precise and rapid control of the microrobotic guidewire under EMA. Further, the potential clinical effectiveness of the ECMIS for real-time cardiovascular interventions is investigated through preclinical studies in coronary, iliac, and renal arteries of swine models in vivo, where the magnetic steering of the microrobotic guidewire and control of other ECMIS modules are teleoperated by operators in a separate control booth with X-ray shielding. The proposed ECMIS can help medical physicians optimally manipulate interventional devices such as guidewires under minimal radiation exposure.

Safety and efficacy of dedicated guidewire, microcatheter, and guide catheter extension technologies for chronic total coronary occlusion revascularization: Primary results of the Teleflex Chronic Total Occlusion Study.

BACKGROUND: Description of procedural outcomes using contemporary techniques that apply specialized coronary guidewires, microcatheters, and guide catheter extensions designed for chronic total occlusion (CTO) percutaneous revascularization is limited. METHODS: A prospective, multicenter, single-arm study was conducted to evaluate procedural and in-hospital outcomes among 150 patients undergoing attempted CTO revascularization utilizing specialized guidewires, microcatheters and guide extensions. The primary endpoint was defined as successful guidewire recanalization and absence of in-hospital cardiac death, myocardial infarction (MI), or repeat target lesion revascularization (major adverse cardiac events, MACE). RESULTS: The prevalence of diabetes was 32.7%; prior MI, 48.0%; and previous bypass surgery, 32.7%. Average (mean ± standard deviation) CTO length was 46.9 ± 20.5 mm, and mean J-CTO score was 1.9 ± 0.9. Combined radial and femoral arterial access was performed in 50.0% of cases. Device utilization included: support microcatheter, 100%; guide catheter extension, 64.0%; and mean number of study guidewires/procedure was 4.8 ± 2.6. Overall, procedural success was achieved in 75.3% of patients. The rate of successful guidewire recanalization was 94.7%, and in-hospital MACE was 19.3%. Achievement of TIMI grade 2 or 3 flow was observed in 93.3% of patients. Crossing strategies included antegrade (54.0%), retrograde (1.3%) and combined antegrade/retrograde techniques (44.7%). Clinically significant perforation resulting in hemodynamic instability and/or requiring intervention occurred in 16 (10.7%) patients. CONCLUSIONS: In a multicenter, prospective registration study, favorable procedural success was achieved despite high lesion complexity using antegrade and retrograde guidewire maneuvers and with acceptable safety, yet with comparably higher risk than conventional non-CTO PCI.

Understanding the Basics of Commonly Used Wires in Interventional Radiology.

A wide variety of wires are available for use in interventional radiology, with wires demonstrating differences in construction, diameter, length, coating, shape, and taper. It is crucial to understand the difference in characteristics between these wires to select the most effective and safe wire for the intended purpose when undertaking a procedure. This article reviews the qualities and functions of different types of wires to aid in this decision-making process.

Case Report: Double Micro-Guidewire Technique for Emergent Rescue of Proximal Stent Collapse During Recanalization of Nonacute Occlusion of Vertebral Artery.

Cerebral arteries are usually tortuous, and in the treatment of cerebrovascular diseases with stenting, a stent deployed may be collapsed at one end, leading to reduced blood flow and subsequent stent occlusion. Immediate rescuing measures should be implemented to prevent severe ischemic events. In this case report, we present a case with V4 segment occlusion of the right vertebral artery treated with endovascular stent angioplasty. An Enterprise stent deployed at the occlusion segment was collapsed at the proximal end after withdrawal of the delivery system. Immediate rescuing measures were taken by navigating a micro-guidewire through the lateral stent mesh at the proximal end into the stent lumen followed by advancing a second micro-guidewire right through the reopened proximal stent end into the stent lumen for deployment of a supporting balloon-expandable Apollo stent to prevent stent collapse. Follow-up digital subtraction angiography 6 months later demonstrated patent stents and unobstructed blood flow.

Are All Wires Created the Same? A Quality Assurance Study of the Stiffness of Wires Typically Employed During Endovascular Surgery Using Tension Dynamometry.

OBJECTIVE: There have only been a few studies on the stiffness and load bearing characteristics of guidewires used to deliver devices during endovascular procedures, particularly endovascular aneurysm repair. The aim of this study was to compare the load bearing characteristics of typical stiff and floppy wires, including in the context of consistency for each wire type. METHODS: Two sets of stiff guidewires (Lunderquist Extra-Stiff and Amplatz Super Stiff [0.035" × 260 cm]), were compared with a floppy hydrophilic guidewire (Radifocus Stiff M [0.035" × 260 cm]). Radial stiffness was defined as the force (newtons [N]) needed to deform the wires on an electromechanical dynamometer. Tests were repeated with three runs on three sets of the same wire to check for consistency. Data were logged on proprietary dynamometric software and peak load values assessed per wire. Peak deformation forces (PDFs) from straight configuration to midwire deformation at 15 mm was translated into Microsoft Excel for statistical analysis in Minitab 19 for Windows. RESULTS: There was good agreement within each wire set, with no difference in PDFs from runs for each wire (p > .10). Mean ± standard deviation PDFs were 7.83 ± 0.23 N for the Lunderquist, 9.87 ± 0.92 N for the Amplatz, and 7.84 ± 0.52 N for the Radifocus wires. The Amplatz wire exhibited the greatest resistance to deformation vs. both the Lunderquist and Radifocus wires (p < .001, one way analysis of variance). Both Amplatz and Radifocus wires had non-linear deformation characteristics. CONCLUSION: This study confirmed that the represented hydrophilic wire is more deformable than the stiff wires. The Amplatz wire has complex construction features that yielded surprising baseline stiffness characteristics. The linear stiffness characteristics of the Lunderquist wire possibly contribute to it being the preferred choice for large endograft delivery.

Interventional cardiac MRI using an add-on parallel transmit MR system: In vivo experience in sheep.

PURPOSE: We present in vivo testing of a parallel transmit system intended for interventional MR-guided cardiac procedures. METHODS: The parallel transmit system was connected in-line with a conventional 1.5 Tesla MRI system to transmit and receive on an 8-coil array. The system used a current sensor for real-time feedback to achieve real-time current control by determining coupling and null modes. Experiments were conducted on 4 Charmoise sheep weighing 33.9-45.0 kg with nitinol guidewires placed under X-ray fluoroscopy in the atrium or ventricle of the heart via the femoral vein. Heating tests were done in vivo and post-mortem with a high RF power imaging sequence using the coupling mode. Anatomical imaging was done using a combination of null modes optimized to produce a useable B1 field in the heart. RESULTS: Anatomical imaging produced cine images of the heart comparable in quality to imaging with the quad mode (all channels with the same amplitude and phase). Maximum observed temperature increases occurred when insulation was stripped from the wire tip. These were 4.1℃ and 0.4℃ for the coupling mode and null modes, respectively for the in vivo case; increasing to 6.0℃ and 1.3℃, respectively for the ex vivo case, because cooling from blood flow is removed. Heating < 0.1℃ was observed when insulation was not stripped from guidewire tips. In all tests, the parallel transmit system managed to reduce the temperature at the guidewire tip. CONCLUSION: We have demonstrated the first in vivo usage of an auxiliary parallel transmit system employing active feedback-based current control for interventional MRI with a conventional MRI scanner.

A bedside rescue method for retrieving retained guidewires: The 'Suck Out' technique.

BACKGROUND: Central venous catheter guidewire retention is classed as a 'never event' in the United Kingdom, with the potential for significant patient harm. If the retained guidewire remains within the central venous catheter lumen, bedside techniques may facilitate guidewire retrieval. However, these techniques may be ineffective if the guidewire has already passed below skin level. We investigated a novel 'suck out' technique for bedside guidewire retrieval and compared this against traditional retrieval methods. METHODS: Simulation 1: in a benchtop model, seven different central venous catheters had their corresponding guidewire placed in the last 2 cm of the catheter tip which was immersed horizontally in fluid. A 50-mL syringe was attached to the distal lumen central venous catheter hub and suction applied for 5 s, and the distance of guidewire retraction was recorded. Simulation 2: a central venous catheter guidewire was intentionally retained within the catheter at either 5 cm above or below skin level in a pigskin model. Simple catheter withdrawal, catheter clamping withdrawal and the 'suck out' method were compared for efficacy using Fisher's exact test. RESULTS: Simulation 1: retained guidewires were retracted by 13 cm on average. Simulation 2: when guidewires were retained 5 cm above skin level, all retrieval methods were 100% effective; however, when retained 5 cm below skin level, simple catheter withdrawal was ineffective, clamping and withdrawal was only 10% effective and the 'suck out' technique was 90% effective (p < 0.001). CONCLUSION: The 'suck out' technique can effectively retract guidewires retained within central venous catheter lumens and demonstrates superiority over traditional methods of retained guidewire extraction in simulated models.

Toolbox for Coronary Chronic Total Occlusion Percutaneous Coronary Intervention.

Since the publication of the hybrid algorithm there has been rapid development of new specialty wires, microcatheters, guide extensions, and low-profile balloons to facilitate successful coronary chronic total occlusion percutaneous coronary intervention. With development of new devices, it is best to categorize them by design and intended task. This enables a safe and systematic approach to coronary chronic total occlusion percutaneous coronary intervention and avoid overlap and waste. This article serves as a guide for tool selection for the interventional cardiologist performing coronary chronic total occlusion percutaneous coronary intervention.

Rational guidewire use in the coronary chronic total occlusion interventions.

BACKGROUND: Procedures for coronary chronic total occlusion (CTO) are still a clinical challenge with relatively lower success rates. Recent advances in the biotechnology and introduction of CTO-dedicated guidewires have increased the procedural success rate of CTO interventions. Herein, we aimed to reveal the clinical and angiographic predictors of the crossability of the initial guidewire choice and rational guidewire usage in CTO interventions. A total of 177 patients with an indication for a coronary CTO procedure were included in this study. The use of 1-3 guidewires and crossing of the CTO lesion with the initial guidewire choice was defined as rational guidewire usage. The CTO lesions were classified according to the Japanese chronic total occlusion registry (J-CTO) and EuroCTO scores for evaluating the difficulty of the procedures. Then, a statistical analysis was performed to assess the initial guidewire choice, crossability, and contributors to rational guidewire usage. RESULTS: The mean J-CTO score was 1.42 ± 1.16, and the mean EuroCTO score was 1.44 ± 1.18. The success rate of the procedures was 90.4%. The initial guidewire choice crossed the lesion in 44.1% of the cases, in which 1-3 guidewires were used (82.1%). The crossability of the polymeric and moderate stiff tip guidewires was higher (82.1% and 64.1%, respectively), and the Pilot series was the most successful brand (36.2%). Logistic regression analysis confirmed that J-CTO score, procedural technique, guidewire type, and stiffness of the tip were the major predictors of rational guidewire usage. CONCLUSION: Our analysis showed that the use of polymeric and moderate stiff tip guidewires, particularly the Pilot brand, were associated with rational guidewire usage in easy and intermediate difficulty CTO cases.