Evaluation of an Electromagnetic 3D Navigation System to Facilitate Endovascular Tasks: A Feasibility Study

A Steerable and Electromagnetically Tracked Catheter: Navigation Performance Compared With Image Fusion in a Swine Model

PURPOSE

Cannulation of visceral vessels is necessary during fenestrated and branched endovascular aortic repair. In an attempt to reduce the associated radiation and contrast dose, an electromagnetically (EM) trackable and manually steerable catheter has been developed. The purpose of this preclinical swine study was to evaluate the cannulation performance and compare the cannulation performance using either EM tracking or image fusion as navigation tools.

MATERIALS AND METHODS

Both renal arteries, the superior mesenteric artery, and the celiac trunk were attempted to be cannulated using a 7F steerable, EM trackable catheter in 3 pigs. Seven operators attempted cannulation using first 3-dimensional (3D) image navigation with EM tracking and then conventional image fusion guidance. The rate of successful cannulation was recorded, as well as procedure time and radiation exposure. Due to the lack of an EM trackable guidewire, cannulations that required more than 1 attempt were attempted only with image fusion. The EM tracking position data were registered to preoperative 3D images using a vessel-based registration algorithm.

RESULTS

A total of 72 cannulations were attempted with both methods, and 79% (57) were successful on the first attempt for both techniques. There was no difference in cannulation rate (p=1), and time-use was similar. Successful cannulation with image fusion was achieved in 97% of cases when multiple attempts were allowed.

CONCLUSION

This study demonstrated the feasibility of a steerable and EM trackable catheter with 3D image navigation. Navigation performance with EM tracking was similar to image fusion, without statistically significant differences in cannulation rates and procedure times. Further studies are needed to demonstrate this utility in patients with aortic disease.

CLINICAL IMPACT

Electromagnetic tracking in combination with a novel steerable catheter reduces radiation and contrast media doses while providing three-dimensional visualization and agile navigation during endovascular aortic procedures.

A Systematic Review of Simulation-Based Training in Vascular Surgery

Introduction

Recent advancements in surgical technology, reduced working hours, and training opportunities exacerbated by the COVID-19 pandemic have led to an increase in simulation-based training. Furthermore, a rise in endovascular procedures has led to a requirement for high-fidelity simulators that offer comprehensive feedback. This review aims to identify vascular surgery simulation models and assess their validity and levels of effectiveness (LoE) for each model in order to successfully implement them into current training curricula.

Methods

PubMed and EMBASE were searched on January 1, 2021, for full-text English studies on vascular surgery simulators. Eligible articles were given validity ratings based on Messick’s modern concept of validity alongside an LoE score according to McGaghie’s translational outcomes.

Results

Overall 76 eligible articles validated 34 vascular surgery simulators and training courses for open and endovascular procedures. High validity ratings were achieved across studies for: content (35), response processes (12), the internal structure (5), relations to other variables (57), and consequences (2). Only seven studies achieved an LoE greater than 3/5. Overall, ANGIO Mentor was the most highly validated and effective simulator and was the only simulator to achieve an LoE of 5/5.

Conclusions

Simulation-based training in vascular surgery is a continuously developing field with exciting future prospects, demonstrated by the vast number of models and training courses. To effectively integrate simulation models into current vascular surgery curricula and assessments, there is a need for studies to look at trainee skill retention over a longer period of time. A more detailed discussion on cost-effectiveness is also needed.

Updates in Endovascular Procedural Navigation In Canadian Journal of Cardiology

There have been significant advancements in endovascular technology over the past decade. Increasingly complex disease processes are being addressed in a less invasive fashion, while still relying on standard two-dimensional, gray-scale fluoroscopy imaging to guide the procedures. With the advent of flat panel detectors as standard on fluoroscopy units and the utilization of fluoroscopy cone-beam computed tomography, the development of improved imaging tools has occurred which will help improve the imaging modalities used to perform these endovascular procedures. . Fusion imaging, the overlay of pre-operative 3-dimensional computed tomography images helps interventionalists perform endovascular procedures. Building on this technology, improvements in its function and utilization have occurred with the additional application of artificial intelligence and machine learning - allowing the images to independently accommodate to changes in the visualized anatomy. Corresponding development of navigation systems, allowing for the tracking of endovascular tools within these images using either fiberoptics of electromagnetic field generators, are looking to improve the accuracy of the procedures while reducing the need for radiation and contrast agents. These tools are making a dramatic change in our ability to perform complex endovascular procedures, and are the future gold standard. Ultimately, these will allow procedures to occur more quickly and more safely.

Novel EM Guided Endovascular Instrumentation for In Situ Endograft Fenestration

Objective: This work aims at providing novel endovascular instrumentation to overcome current technical limitations of in situ endograft fenestration including challenges in targeting the fenestration site under fluoroscopic control and supplying mechanical support during endograft perforation. Technology: Novel electromagnetically trackable instruments were developed to facilitate the navigation of the fenestration device and its stabilization at the target site. In vitro trials were performed to preliminary evaluate the proposed instrumentation for the antegrade in situ fenestration of an aortic endograft, using a laser guidewire designed ad hoc and the sharp end of a commercial endovascular guidewire. Results: In situ fenestration was successfully performed in 22 trials. A total of two laser tools were employed since an over bending of laser guidewire tip, due to its manufacturing, caused the damage of the sensor in the first device used. Conclusions: Preliminary in vitro trials demonstrate the feasibility of the proposed instrumentation which could widespread the procedure for in situ fenestration. The results obtained should be validated performing animal studies. Clinical Impact: The proposed instrumentation has the potential to expand indications for standard endovascular aneurysm repair to cases of acute syndromes.

Optimizing imaging and reducing radiation exposure during complex aortic endovascular procedures

Improvements in endovascular technologies and development of custom-made fenestrated and branched endografts currently allow clinicians to treat complex aortic lesions such as thoraco-abdominal and aortic arch aneurysms once treatable with open repair only. These advances are leading to an increase in the complexity of endovascular procedures which can cause long operation times and high levels of radiation exposure. This in turn places pressure on the vascular surgery community to display more superior interventional skills and radiological practices. Advanced imaging technology in this context represents a strong pillar in the treatment toolbox for delivering the best care at the lowest risk level. Delivering the best patient care while managing the radiation and iodine contrast media risks, especially in frail and renal impaired populations, is the challenge aortic surgeons are facing. Modern hybrid rooms are equipped with a wide range of new imaging applications such as fusion imaging and cone-beam computed tomography (CBCT). If these technologies contribute to reducing radiation, they can be complex and intimidating to master. The aim of this review is to discuss the fundamentals of good radiological practices and to describe the various imaging tools available to the aortic surgeon, both those available today and those we anticipate will be available in the near future, from equipment to software, to perform safe and efficient complex endovascular procedures.

Ultrasound-based tracking strategy for endoluminal devices in cardiovascular surgery

BACKGROUND

Magnetic endovascular navigation of wireless or soft-tethered endoluminal devices was recently proposed in the literature. This approach allows for innovative therapeutic procedures, but developing a real-time tracking strategy, compatible with magnetic dragging, is a challenging problem and is not yet solved.

METHODS

Two-dimensional (2D) imaging ultrasound (US)-based tracking algorithms applied to a platform for cardiovascular treatment, i.e. the MicroVAST platform, were implemented and tested for deriving the optimal strategy for tracking endovascular devices dragged by magnetic locomotion.

RESULTS

The algorithm, based on the combination of Shi-Tomasi features detector, Lucas-Kanade features tracking and watershed segmentation technique, was demonstrated to be the most reliable and accurate solution for the implementation of the tracking strategy of soft-tethered endoluminal devices.

CONCLUSIONS

Our results encourage the development of US-based tracking algorithms for endoluminal devices in cardiovascular surgery, paving the way to a robust three-dimensional (3D) imaging US-based tracking strategy implementation. Copyright © 2014 John Wiley & Sons, Ltd.

Improved catheter navigation with 3D electromagnetic guidance

PURPOSE

To evaluate the in vitro performance of an electromagnetic navigation system (ENS) in aortic arch branch cannulation and describe its role for fenestrated endograft deployment.

METHODS

Reconstructed multidetector computed tomography images of silicone phantoms representing the aortic arch and a thoracoabdominal aortic aneurysm were uploaded onto the StealthStation workstation, which provided 3-dimensional visualization of a guidewire by tracking sensors on its tip. For the evaluation of aortic arch branch cannulation, 9 operators were asked to cannulate the phantom's common carotid and left subclavian arteries using the (1) ENS, (2) a 2-dimensional (2D) screen setting simulating fluoroscopy, and (3) both imaging modalities. Analysis included procedure times, number of wall hits, and the Imperial College Complex Cannulation Scoring Tool (IC3ST) qualitative performance score. To evaluate the ability of the ENS during positioning of a fenestrated stent-graft over the visceral segment, a custom-made 4-vessel fenestrated stent-graft with sensors on the fenestrations was deployed 5 consecutive times using the ENS as the exclusive imaging technique.

RESULTS

In the aortic arch model, cannulation times were significantly longer in the ENS group. However, compared with the 2D version, using both imaging modalities reduced fluoroscopic times [median 26.5 seconds (IQR 19.7-30.7) vs. 87 seconds (IQR 64-128), p<0.0001] and wall hits [median 8.5 (IQR 16-38) vs. 14 (IQR 11-160, p<0.05), while improving IC3ST performance scores [31/35 (IQR 30-31.2) vs. 25/35 (IQR 24-27), p<0.05]. Following deployment of the endograft with tracked fenestrations, the 4 visceral vessels were cannulated in all cases using only the ENS.

CONCLUSION

The use of the ENS as a complementary imaging modality might be beneficial in terms of radiation exposure, cannulation performance, and positioning of intravascular devices.