Endovascular treatment of complex peripheral artery disease and chronic total occlusions remains a significant challenge. This is largely due to limited distal control of devices used and reliance on proximal manipulation with conventional catheters. To bridge this gap, we previously developed the CathPilot, a modular steerable catheter that integrates a self-expanding nitinol frame for local anchoring with a real-time graphical user interface that provides cross-sectional tip position feedback alongside fluoroscopy. This study compares the CathPilot with conventional non-steerable catheters in a simulated-use, within-subjects design. Eight interventional clinicians each performed three lesion-crossing attempts per device in a silicone phantom model of human vasculature. Silicone lesions were positioned in the left superficial femoral artery. Objective endpoints included lesion-crossing success, procedure time, fluoroscopy time, and radiation dose. Subjective assessments included the System Usability Scale (SUS) for perceived usability and NASA Task Load Index (NASA-TLX) for operator workload. Combining objective performance with human-factors instruments enabled a comprehensive assessment of the CathPilot’s procedural usability against conventional catheters. CathPilot achieved a 92

Abdominal aortic aneurysms (AAA) are often repaired through an endovascular approach known as endovascular aneurysm repair (EVAR). The success and duration of these challenging procedures are primarily attributable to the accuracy and reliability of navigating corresponding interventional devices. This study investigates the performance of conventional nonsteerable and steerable catheters in EVAR procedures, focusing on two primary metrics: reachable workspace and gate cannulation success. We developed two abdominal aortic aneurysm (AAA) phantoms using patient CT images for our experiments. Under X-ray fluoroscopy guidance, the reachable workspace was quantified, and gate cannulation success rates, cannulation time, and fluoroscopy times were recorded for both nonsteerable and steerable catheters and were compared. We were unable to observe statistically significant differences between the two catheter types in overall cannulation success rates or fluoroscopy time. However, in challenging anatomical scenarios (particularly a more challenging gate location), the steerable catheter showed statistically significant advantages in success rates and cannulation times. While there were no statistical differences in reachable workspace between nonsteerable and steerable catheters when considering the whole aneurysm, segmented analysis showed that the steerable catheter performed better in the central region, and nonsteerable catheters performed better in the peripheral region. This study provides a systematic method for quantifying the performance of endovascular devices. The findings suggest that while steerable catheters may offer advantages in complex anatomical conditions, nonsteerable catheters are preferable in peripheral areas of the aneurysm. These insights can inform catheter selection in EVAR, potentially influencing device design and clinical practice.

Catheter based procedures are typically guided by X-Ray, which suffers from low soft tissue contrast and only provides 2D projection images of a 3D volume. Intravascular ultrasound (IVUS) can serve as a complementary imaging technique. Forward viewing catheters are useful for visualizing obstructions along the path of the catheter. The CathEye system mechanically steers a single-element transducer to generate a forward-looking surface reconstruction from an irregularly spaced 2-D scan pattern. The steerable catheter leverages an expandable frame with cables to manipulate the distal end independently of vessel tortuosity. The tip position is estimated by measuring the cable displacements and used to create surface reconstructions of the imaging workspace with the single-element transducer. CathEye's imaging capabilities were tested with an agar phantom and an ex vivo chronic total occlusion (CTO) sample while the catheter was confined to various tortuous paths. The CathEye maintained similar scan patterns regardless of path tortuosity and was able to recreate major features of the imaging targets, such as holes and extrusions. The feasibility of forward-looking IVUS with the CathEye is demonstrated in this study. The CathEye mechanism can be applied to other imaging modalities with field-of-view (FOV) limitations and represents the basis for an interventional device fully integrated with image guidance.

Fenestrated endovascular aneurysm repair remains a technically challenging procedure in the presence of complex anatomy, as it increases the difficulty of target vessel cannulation and prolongs procedure time and fluoroscopy radiation exposure. This paper aims to design, develop, and assess a novel steerable catheter, the SideEye, and compare its performance with conventional catheters in a thoracoabdominal aortic aneurysm phantom model. Users were asked to perform target vessel cannulation under fluoroscopic guidance using the SideEye and conventional non-steerable and steerable catheters. The experiment was divided into two cases based on the stent graft orientation (aligned and misaligned). Total procedure times, individual target vessel cannulation times, and exposure times were analyzed and compared in each case. In the misaligned case, the average cannulation times of all target vessels were 703 ± 274 s using the non-steerable catheter, 517 ± 309 s using the steerable catheter, and 199 ± 91.0 s using the SideEye. The average exposure times were 12 ± 4.6 min using the non-steerable catheter, 8.6 ± 4.1 min using the steerable catheter, and 3.0 ± 1.1 min using the SideEye. Target vessel cannulation using the SideEye significantly reduced procedure time and overall exposure time, compared to conventional devices.

Objectives : Peripheral endovascular revascularization procedures often fail due to technical limitations of guidewire support, steering, and visualization. The novel CathPilot catheter aims to address these challenges. This study assesses the safety and feasibility of the CathPilot and compares its performance to conventional catheters for peripheral vascular interventions. Methods : The study compared the CathPilot to non-steerable and steerable catheters. The success rates and access times for a relevant target inside a tortuous vessel phantom model were assessed. The reachable workspace within the vessel and the guidewire's force delivery capabilities were also evaluated. To validate the technology, chronic total occlusion tissue samples were used ex vivo to compare crossing success rates with conventional catheters. Finally, in vivo experiments in a porcine aorta were conducted to evaluate safety and feasibility. Results : The success rates for reaching the set targets were 31%, 69%, and 100% with the non-steerable catheter, the steerable catheter, and the CathPilot, respectively. CathPilot had a significantly larger reachable workspace, and allowed for up to four times higher force delivery and pushability. In crossing of chronic total occlusion samples, the CathPilot achieved a success rate of 83% and 100%, for fresh and fixed lesions respectively, which was also significantly higher than conventional catheters. The device was fully functional in the in vivo study, and there were no signs of coagulation or damage to the vessel wall. Conclusion : This study shows the safety and feasibility of the CathPilot system and its potential to reduce failure and complication rates in peripheral vascular interventions. The novel catheter outperformed conventional catheters in all defined metrics. This technology can potentially improve the success rate and outcome of peripheral endovascular revascularization procedures.

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.

Fenestrated endovascular aneurysm repair presents a significant technical challenge in cases involving complex anatomy. This complexity often leads to difficulties in target vessel cannulation, prolonged procedure time, and increased fluoroscopy radiation exposure. To address these challenges, this paper aims to design, develop, and assess a novel steerable catheter, the SideEye (Fig 1), and compare its performance to that of conventional catheters in a thoracoabdominal aortic aneurysm phantom model. Seven users were asked to perform target vessel cannulation using the SideEye catheter and two conventional catheters (one non-steerable and one steerable) under fluoroscopic guidance. The study was designed to compare the performance of the SideEye catheter with that of the conventional catheters in two experimental cases: aligned and misaligned stent graft orientation. The primary outcome measures for this study were total procedure time and individual target vessel cannulation times. Exposure times were also recorded to assess the radiation exposure associated with each catheter. In the misaligned case, the average cannulation times for all target vessels were 703 ± 274 seconds using the non-steerable catheter, 517 ± 309 seconds using the steerable catheter, and 199 ± 91.0 seconds using the SideEye catheter (Fig 2). The average exposure times were also analyzed for each catheter in the misaligned case. The non-steerable catheter had an average exposure time of 12 ± 4.6 minutes, the steerable catheter had an average exposure time of 8.6 ± 4.1 minutes, and the SideEye catheter had an average exposure time of 3.0 ± 1.1 minutes (Fig 2). These results indicate a significant difference in cannulation times and exposure times between the SideEye catheter and the conventional catheters (P < .05). Overall, these findings demonstrate that target vessel cannulation using the SideEye catheter significantly reduced both procedure time and overall exposure time, compared with conventional catheters.Fig 2Average cannulation times and exposure times of all target vessels, in the misaligned stent graft orientation, using the non-steerable catheter, steerable catheter, and SideEye catheter.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Accurate catheter navigation is a significant challenge for minimally invasive catheter-based procedures. The catheter’s long length, high flexibility, mechanical interactions with the tortuous anatomy, and inadequate feedback from 2D projection x-ray limit accurate catheter tip control. This thesis describes the design, development, and evaluation of a novel catheter navigation system that directly addresses the fundamental limitations of conventional devices. We designed and developed a novel expandable frame and manual steering system using principles from cable-driven parallel manipulators to provide accurate, reliable, and localized control and feedback of the catheter tip position. The device’s performance under different tortuosity conditions and different expansion sizes were assessed, showing complete workspace coverage with localized steering within the frame and position tracking with submillimetre accuracy (~0.38mm) irrespective of the expansion size and path tortuosity. With the added control and feedback, the CathPilot promises to overcome the limitations of conventional catheter navigation and will allow for the next generation of interventional devices.

Accurate device navigation and control are significant challenges in various minimally invasive cardiovascular interventions. The long length of the devices used (e.g., catheters and guidewires), their high flexibility, and their engagement with the tortuous anatomy limit the accurate and reliable control and navigation of the device's tip. This article aims to design, develop, and assess a novel alternative solution that promises to overcome the major limitations of conventional devices. By utilizing an expandable cable-driven mechanism and a corresponding 3-D cam surface for cable length adjustment, we propose a fully manually operated system that can be navigated through the tortuous anatomy and then teleoperated to allow for accurate, reliable, and localized position control and tracking of the device. In this article, the methods of design, development, and verifications of this system are presented. The system's performance is assessed under different path tortuosity conditions and different opening diameters of the expandable frame. Our results indicate that the proposed system provides complete teleoperation of the device within the full reachable workspace of the mechanism and allows for positioning and tracking of the device with submillimeter accuracy irrespective of the tortuosity of the path and expansion size of the frame. Ex-vivo phantom model experiments also show the device significantly outperforms conventional devices in terms of navigation time and success rate. The CathPilot allows for direct manipulation, accurate positioning, and tracking of the device tip relative to the anatomy, promising to overcome some of the major limitations of conventional interventional devices.

Conventional catheter-based procedures suffer from inaccurate device steering, and navigation limitations as the long and flexible devices are manipulated remotely from outside the patient body. A recently developed approach aims to overcome these limitations by using an expandable cable-driven parallel mechanism for local device manipulation and tracking relative to the anatomy. However, as the frame of this system is flexible and may be constrained by unknown anatomical constraints inside the patient body, accurate system identification is a key and critical step which would ultimately determine the accuracy in device steering and tracking. In this paper, we present an optimization approach to identify the parameters of an expandable cable-driven parallel mechanism deployed in an unknown environment, merely based on measurements of the cable length variations that would be available outside the patient body. We have verified and validated the proposed approach in terms of accuracy in the prediction of the frame shape and cable anchor locations, as well as its tracking accuracy. Both simulations and experimental studies have been performed, and we have demonstrated that the proposed method allows for rapid frame shape and anchor position estimation with unknown anatomical constraints and permits localized device tracking and steering with submillimeter accuracy.

Peripheral arterial percutaneous vascular interventions have high immediate technical failure rates (∼20%). The most common mode of failure is the inability to cross lesions. The purpose of this study is to demonstrate the feasibility using a novel steering catheter (CathPilot) for crossing peripheral arterial chronic total occlusions (CTOs). A prototype CathPilot device was manufactured (Fig 1). Three-dimensional, printed lesions were placed within an arterial phantom to simulate a CTO. Four operators were blinded to the lesions and attempted to cross the lesion with a conventional guidewire and KMP catheter and with a guidewire/CathPilot. The crossing time was measured. Aluminum foil was mounted on the surface of another lesion, and users were asked to puncture as much of the lesion surface as possible within 5 minutes using a guidewire and conventional KMP, Oscor steering catheter, and the CathPilot catheter. The mean puncture force delivered was also measured and compared. Where users failed to cross lesions with a conventional approach (15-minute time limit), all users succeeded with the CathPilot in less than 5 minutes. The CathPilot was effective at covering more of the surface of the lesion compared with KMP and Oscor catheters (Fig 2). The guidewire delivered on average 43.7 g of force with the CathPilot compared with 12.7 g with a KMP 16.9 g with the Oscor (Fig 2). Crossing CTOs may be challenging due to the inability to effectively aim the guidewire tip and apply sufficient force to the lesion surface. The CathPilot enables shorter crossing times with precise steering and can generate more puncture force compared with conventional catheters and currently commercially available steering catheters. Future work will determine if the CathPilot can be used to cross arterial lesions in vivo.Fig 2Guidewire puncture forces and surface area coverage using conventional (KMP) catheter, Oscor steering catheter, and CathPilot. The KMP catheter placed the guidewire tip on only the periphery, the Oscor catheter covered less surface area compared with the CathPilot.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Endovascular wires and devices for peripheral arterial disease therapy have evolved greatly, yet failure rates of these procedures remain high. Information on lesion composition may inform device selection to improve the success rates of these procedures. This paper, presents an approach for informed guidewire selection. The objective of this study is to quantitatively assess the performance of a radiofrequency powered guidewire in the crossing of various morphology types of peripheral chronic total occlusions. Samples taken from amputated patient limbs are characterized by magnetic resonance imaging. Using a customized catheter test station, the performance of a radiofrequency powered guidewire in puncturing these lesions is compared to a conventional guidewire, and to itself when not powered. The analysis includes quantitative and statistical comparisons of the puncture forces experienced by the different guidewires in "hard" vs. "soft" lesions as well as qualitative assessment of deflections, buckling and puncture success of the wires. Results indicate that the use of radiofrequency ablation significantly reduces the required puncture force, reduced events of buckling and deflection, and resulted in a significantly higher puncture success rate.