Characterising the incidence and mode of visceral stent failure after fenestrated endovascular aneurysm repair (FEVAR).

BackgroundIn FEVAR, visceral stents provide continuity and maintain perfusion between the main body of the stent and the respective visceral artery. The aim of this study was to characterise the incidence and mode of visceral stent failure (type Ic endoleak, type IIIa endoleak, stenosis/kink, fracture, crush and occlusion) after FEVAR in a large cohort of patients at a high-volume centre.MethodsA retrospective review of visceral stents placed during FEVAR over 15 years (February 2003-December 2018) was performed. Kaplan-Meier analyses of freedom from visceral stent-related complications were performed. The outcomes between graft configurations of varying complexity were compared, as were the outcomes of different stent types and different visceral vessels.ResultsVisceral stent complications occurred in 47/236 patients (19.9%) and 54/653 stents (8.3%). Median follow up was 3.7 years (IQR 1.7-5.3 years). There was no difference in visceral stent complication rate between renal, SMA and coeliac arteries. Visceral stent complications were more frequent in more complex grafts compared to less complex grafts. Visceral stent complications were more frequent in uncovered stents compared to covered stents. Visceral stent-related endoleaks (type Ic and type IIIa) occurred exclusively around renal artery stents. The most common modes of failure with SMA stents were kinking and fracture, whereas with coeliac artery stents it was external crush.ConclusionVisceral stent complications after FEVAR are common and merit continued and close long-term surveillance. The mode of visceral stent failure varies across the vessels in which the stents are located

Experienced endovascular interventionalists objectively improve their skills by attending carotid artery stent training courses

Objective. Carotid artery stenting (CAS) is an advanced endovascular intervention with a steep learning curve. Virtual reality (VR) simulation has been proposed as a means to train and objectively assess technical performance. 1: 6 Aim. To objectively assess psychomotor skills acquisition of experienced interventionalists attending a two-day CAS course, using a VR simulator. Methods. Both cognitive and technical skills of 11 interventionalists were trained in a two-day course using didactic sessions, case reviews, supervised VR simulation and live-cases. Pre- and post-course skills were assessed through performance on the same CAS procedure using metrics derived from the simulator. Results. Significant differences were noted between pre- and post-course performance for procedure (36 vs. 20 min., p = 0.005), X-ray (20 vs. 11 min., p = 0.016) and delivery-retrieval time of the embolic protection device (12 vs. 9 min., p = 0.007). Advancement of the guiding catheter without a leading wire occurred to a greater extent pre- versus post-course (199 vs. 152 mm., p = 0.050) as did spasm of the internal carotid artery (4 vs. 2, p = 0.049). Conclusions. This study has objectively proven a benefit for experienced interventionalists to attend CAS courses for skills acquisition measured by a VR simulator. These data can be used to offer participants an insight into their skills and objectively audit course efficacy

Identification of skills common to renal and iliac endovascular procedures performed on a virtual reality simulator

Introduction. There is a learning curve in the acquisition of endovascular skills for the treatment of vascular disease. Integration of Virtual reality (VR) simulator based training into the educational training curriculum offers a potential solution to overcome this learning curve. However evidence-based training curricula that define which tasks, how often and in which order they should be performed have yet to be developed. The aim of this study was to determine the nature of skills acquisition on the renal and iliac modules of a commercially-available VR simulator. Method. 20 surgical trainees without endovascular experience were randomised to complete eight sessions on a VR iliac (group A) or renal (group B) training module. To determine skills transferability across the two procedures, all subjects performed two further VR cases of the other procedure. Performance was recorded by the simulator for parameters such as time taken, contrast fluid usage and stent placement accuracy. Results. During training, both groups demonstrated statistically significant VR learning curves: group A for procedure time (p < 0.001) and stent placement accuracy (p = 0.013) group B for procedure time (p < 0.001), fluoroscopy time (p = 0.003) and volume of contrast fluid used (p < 0.001). At crossover, subjects in group B (renal trained) performed to the same level of skill on the simulated iliac task as group A. However, those in group A (iliac trained) had a significantly higher fluoroscopy time (median 118 vs 72 secs, p = 0.020) when performing their first simulated renal task than for group B. Conclusion. Novice endovascular surgeons can significantly improve their performance of simulated procedures through repeated practice on VR simulators. Skills transfer between tasks was demonstrated but complex task training, such as selective arterial cannulation in simulators and possibly in the real world appears to involve a separate skill. It is thus suggested that a stepwise and hierarchical training curriculum is developed for acquisition of endovascular skill using VR simulation to supplement training on patients

Endovascular skills training and assessment

Objective: Evolving endovascular therapies have transformed the management of vascular disease. At the same time, the increasing use of non-invasive vascular imaging techniques has reduced the opportunities to gain the required basic wire and catheter handling skills by performing diagnostic catheterizations. This article reviews the evidence for alternative tools currently available for endovascular skills training and assessment. Methods: A Literature search was performed on pubmed using combinations of the following keywords; endovascular, skills, training, simulation, assessment and learning curve. Additional articles were retrieved from the reference lists of identified papers as well as discussion with experts in the arena of medical education. Results: Available alternatives to training on patients inclue synthetic models, anesthetized animals, human cadavers and virtual reality (VR) simulation. VR simulation is a useful tool enabling objective demonstration of improved skills performance both in simulated performance and in subsequent in-vivo performance. Assessment modalities reviewed include time action analysis, error analysis, global rating scales, procedure specific checklists and VR simulators. Assessment in training has been widely validated using VR simulation. Rating scales and checklists are presently the only assessment modalities that have demonstrated utility outside the training lab. Conclusion: The tools required for a structured proficiency based endovascular training curriculum are already available. Organization of training programs needs to evolve to make full use of modern simulation capability for technical and non-technical skills training

Cognitive training improves clinically relevant outcomes during simulated endovascular procedures

Objectives: Virtual reality (VR) simulation has been suggested to objectively assess endovascular skills. The aim of this study was to determine the impact of cognitive training on technical performance of inexperienced subjects on a commercially available VR simulator (VIST, Vascular Intervention Simulation Trainer, Mentice, Gothenburg, Sweden). Methods: Forty-seven subjects treated an identical virtual iliac artery stenosis endovascularly. Surgical trainees without endovascular experience were allocated to two training protocols: group A(1) (n = 10) received a 45 minute didactic session followed by an expert demonstration of the procedure that included error-based learning, whereas group A(2) (n = 10) was only given a demonstration of an iliac dilation and stent procedure. All trainees performed the intervention immediately following the expert demonstration. Twenty-seven endovascular physicians were recruited (> 100 endovascular interventions). Performance was assessed using the quantitative (procedure and fluoroscopy time) and qualitative (stent/vessel ratio and residual stenosis) assessment parameters recorded by the simulator. Results: The end-product (qualitative metrics) in the cognitive-skills group A, was similar to those of the endovascular physicians, though A(2) performed significantly worse than the physicians (group B): stent/vessel ratio (A(1) 0.89 vs B 0.96, P = .960; A(2) 0.66 vs B 0.96, P = .001) and residual stenosis (A(1) 11 vs B 4%, P = .511; A2 35 vs B 4%, P < .001). Group At took longer to perform the procedure (A, 982 vs B 441 seconds, P < .001), with greater use of fluoroscopy than group B (A, 609 vs B 189 seconds, P < .001) whereas group A(2) performed the intervention as quickly as group B (A(2) 358 vs B 441 seconds, P = .192) but used less fluoroscopy (A(2) 120 vs 189 seconds, P = .002). Conclusion: Cognitive-skills training significantly improves the quality of end-product on a VR endovascular simulator, and is fundamental prior to assessment of inexperienced subjects