Clinical Validations

Endovascular aneurysm repair simulation can lead to decreased fluoroscopy time and accurately delineate the proximal seal zone

Kim AH, Kendrick DE, Moorehead PA, Nagavalli A, Miller CP, Liu NT, Wang JC, Kashyap VS.

Division of Vascular Surgery and Endovascular Therapy, University Hospitals—Case Medical Center, Cleveland, Ohio

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Evaluation of the Subjective Benefit of Procedure Rehearsal with the PROcedure Rehearsal StudioTM Prior to Endovascular Aortic Aneurysm Repair (EVAR)

John H. Rundback, MD

Medical Director, Interventional Institute at Holy Name Medical Center, Teaneck, NJ

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Endovascular Simulation Leads to Efficiency and Competence in Thoracic Endovascular Aortic Repair Procedures

Daniel E.Kendrick,MD, Andre F.Gosling, MD,Anil Nagavalli, MS, Vikram S.Kashyap,MD, and JohnC.Wang,MD

Division of Vascular Surgery and Endovascular Therapy, University Hospitals—Case Medical Center, Cleveland, Ohio

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An approach to EVAR simulation using patient specific modeling.

Davis GR1, Illig KA2, Yang G2, Nguyen TH2, Shames ML2.

1Division of Vascular & Endovascular Surgery, USF Health Morsani School of Medicine, Tampa, FL.

2Division of Vascular & Endovascular Surgery, USF Health Morsani School of Medicine, Tampa, FL.

Ann Vasc Surg. 2014 Oct;28(7):1769-74.

BACKGROUND: The Simbionix Angiomentor Procedure Rehearsal Studio (PRS) offers accurate virtual anatomy for measurement, stent graft selection, and deployment of endovascular aneurysm repair (EVAR) devices.

METHODS: Selected Gore Excluder EVAR cases from our EVAR database were reviewed and DICOM data loaded into the Simbionix Angiomentor simulator using PRS software. Using centerline measurements created on PRS, neck diameter (D1), length from lowest renal artery to each iliac bifurcation (Ll and Lr), and common iliac artery diameter (Dl and Dr) were recorded. All measurements for device selection were made based on data recorded on the simulator. Simulated EVAR was then performed using PRS on a dual limb endovascular simulator. Changes in device selection based on intraoperative measurements and use of three-dimensional (3D) anatomic overlay made by the attending vascular surgeon performing the case were recorded. The devices actually used for successful repair were considered gold standard for comparison. At the completion of each virtual case, simulations were rated by an experienced vascular surgeon for realism, imaging quality, and final product on a 5-point scale.

RESULTS: Ten cases with complete operative data and available computed tomography scans were chosen at random. Fifty percent of the cases (5/10) had changes in device length when using the “in vivo” 3D volume filled model and angiographic measurements. Analysis of variance revealed no significant differences between the groups in any measurement-main body diameter P = 0.960; main body length P = 0.643; and contralateral limb length P = 0.333. Review of simulation scoring showed ratings of diminished realism (average 2.3/5) due to unrealistic ease of wire passage and gate cannulation; however, simulation imaging and final product were scored favorably (3.7 and 3.4, respectively).

CONCLUSIONS: The use of centerlines, angiographic measurements, and 3D modeling within the PRS software approaches real-life device selection and represents an opportunity for high fidelity patient-specific preoperative EVAR case rehearsal.

Patient-specific Rehearsal Prior to EVAR: A Pilot Study

 

Desender L, Rancic Z, Aggarwal R, Duchateau J, Glenck M, Lachat M, Vermassen F, Van Herzeele I; EVEREST (European Virtual Reality Endovascular RESearch Team).

Department of Thoracic and Vascular Surgery, Ghent University Hospital, Ghent, Belgium

Eur J Vasc Endovasc Surg. 2013 June;45(6):639-647. doi: 10.1016/j.ejvs.2013.03.006. Epub 2013 Apr 10.

OBJECTIVES: This study aims to evaluate feasibility, face validity, influence on technical factors and subjective sense of utility of patient-specific rehearsal (PsR) prior to endovascular aortic aneurysm repair (EVAR).

DESIGN: A prospective, multicentre pilot study.

METHODS: Patients suitable for EVAR were enrolled and a three-dimensional (3D) model of thepatient’s anatomy was generated. Less than 24 h prior to the real case, rehearsals were conducted in the laboratory or clinical angiosuite. Technical metrics were recorded during both procedures. A subjective questionnaire was used to evaluate realism, technical and human factor aspects (scale 1-5).

RESULTS: Ten patients were enrolled. In one case, the treatment plan was altered based on PsR. In 7/9 patients, the rehearsal significantly altered the optimal C-arm position for the proximal landing zone and an identical fluoroscopy angle was chosen in the real procedure. All team members found the rehearsaluseful for selecting the optimal fluoroscopy angle (median 4). The realism of the EVAR procedure simulation was rated highly (median 4). All team members found the PsR useful to prepare the individual team members and the entire team (median 4).

CONCLUSIONS: PsR for EVAR permits creation of realistic case studies. Subjective evaluation indicates that it may influence optimal C-arm angles and be valuable to prepare the entire team. A randomised controlled trial (RCT) is planned to evaluate how this technology may influence technical and team performance, ultimately leading to improved patient safety.

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Role of patient-specific virtual reality rehearsal in carotid artery stenting.

Willaert WI, Aggarwal R, Van Herzeele I, Plessers M, Stroobant N, Nestel D, Cheshire N, Vermassen F.

Department of Thoracic and Vascular Surgery, Ghent University Hospital, Ghent, Belgium.

Br J Surg. 2012 Sep;99(9):1304-13. doi: 10.1002/bjs.8858.

Background: Recent advances in simulation science permit patient-specific rehearsal of endovascular stenting procedures. This study aimed to evaluate how effectively real interventions are replicated by patient-specific rehearsal technology, and to assess its value as a preparatory tool for the interventionalist and the operating team.

Methods: All patients deemed candidates for carotid artery stenting procedures with suitable computed tomography images were enrolled. Each team member rehearsed the virtual procedure in the laboratory, simulated operating theatre or angiography suite environment immediately before treating the real patient. Dexterity and qualitative metrics were recorded. Subjective questionnaires used a Likert scale from 1 (poor) to 5 (excellent).

Results: Of 18 patients, three were excluded. In 11 of 15 and 13 of 15 patients respectively endovascular tool use and fluoroscopy angles were identical during rehearsal and the real procedure. In a third of patients, the simulator did not adequately predict difficulties in cannulating the stenotic internal or common carotid arteries. The procedure realism, value in evaluating the case, increase in efficiency in tool use, and potential to increase communication, confidence and team performance were all rated highly (4 of 5).

Conclusion: Patient-specific rehearsal was rated highly for both face and content validity. Access strategy, endovascular material use and angiographic imaging were all replicated effectively, although certain biomechanical vessel properties seemed to be replicated to a lesser degree. Patient-specific rehearsal constitutes a unique tool that may help tailor endovascular material choice, and optimize the preoperative preparation of the interventionalist and team.

Simulated Procedure Rehearsal Is More Effective Than a Preoperative Generic Warm-Up for Endovascular Procedures.

Willaert WI, Aggarwal R, Daruwalla F, Van Herzeele I, Darzi AW, Vermassen FE, Cheshire NJ; on behalf of the EuropeanVirtual Reality Endovascular Research Team EVEResT.

*Department of Biosurgery and Surgical Technology Regional Vascular Unit, St Mary’s Hospital, Imperial College, London, United Kingdom ‡Department of Thoracic and Vascular Surgery, Ghent University Hospital, Ghent, Belgium.

Ann Surg. 2012 Jun; 255(6):1184-1189.

INTRODUCTION: Patient-specific simulated rehearsal (PsR) of a carotid artery stenting procedure (CAS) enables the interventionalist to rehearse the case before performing the procedure on the actual patient by incorporating patient-specific computed tomographic data into the simulation software. This study aimed to evaluate whether PsR of a CAS procedure can enhance the operative performance versus a virtual reality (VR) generic CAS warm-up procedure or no preparation at all.

METHODS: During a 10-session cognitive/technical VR course, medical residents were trained in CAS. Thereafter, in a randomized crossover study, each participant performed a patient-specific CAS case 3 times on the simulator, preceded by 3 different tasks: a PsR, a generic case, or no preparation. Technical performances were assessed using simulator-based metrics and expert-based ratings.

RESULTS: Twenty medical residents (surgery, cardiology, radiology) were recruited. Training plateaus were observed after 10 sessions for all participants. Performances were significantly better after PsR than after a generic warm-up or no warm-up for total procedure time (16.3 ± 0.6 vs 19.7 ± 1.0 vs 20.9 ± 1.1 minutes, P = 0.001) and fluoroscopy time (9.3 ± 0.1 vs 11.2 ± 0.6 vs 11.2 ± 0.5 minutes, P = 0.022) but did not influence contrast volume or number of roadmaps used during the “real” case. PsR significantly improved the quality of performance as measured by the expert-based ratings (scores 28 vs 25 vs 25, P = 0.020).

CONCLUSIONS: Patient-specific simulated rehearsal of a CAS procedure significantly improves operative performance, compared to a generic VR warm-up or no warm-up. This technology requires further investigation with respect to improved outcomes on patients in the clinical setting.

World’s first case-specific EVAR rehearsal leads to successful intervention

Contributed by Isabelle van Herzeele, University of Ghent, Belgium.

Department of Thoracic and Vascular Surgery, Ghent University Hospital, Ghent, Belgium.

Vascular News: Tuesday, 06 Mar 2012 12:34

The University Hospital of Ghent, Belgium, which is part of EVEREST (European virtual reality endovascular research team) announced the successful endovascular abdominal aortic aneurysm (EVAR) repair of the first patient after the stent-graft procedure had been practiced on a simulator.

The ultimate dummy run, practicing this endovascular intervention on a virtual patient before their real operation, may not only influence device selection, but also improve the technical performance of the surgeon/radiologists and the awareness and communication.

As the real patient cannot be used, vascular surgeons at the University Hospital of Ghent, Belgium, have used the dual leg Angio Mentor from Simbionix―a virtual reality simulator that allows the creation of individual patient-specific cases. It works by taking the CT scans of the individual patients’ aneurysm anatomy and transforming them into a 3D model with the Simbionix’s PROcedure rehearsal software. The endovascular team―including nurses, anaesthesiologist, assistants, radiographer and the surgeon―can then reiterate the various steps and insert real-life tools into a workstation, which mimics the anticipated reactions of the patients’ body.

Frank Vermassen, lead vascular surgeon at the Department of Thoracic and Vascular Surgery said simulators like the Angio Mentor provide a new and important tool. “Simulation may involve a human actor, rehearsal rubber models or cadavers but perhaps the most attractive is computer-based simulators because the procedure can be repeated. Moreover, evidence suggests that junior doctors learning to do procedures benefit from practicing in a simulated environment, and it is an excellent way of providing trainees with the vital skills and strategies for dealing with the unexpected.

“The idea we have with this machine is to take it one step further and not to just allow us to train or judge, but to say for a specific patient ‘let’s import their information and test the procedure before we do it for real,” he said.

The PROcedure rehearsal software―FDA cleared in February 2012 for the EVAR application―has been used previously in carotid artery stenting but has not been used to rehearse the endovascular exclusion of an aortic aneurysm. The first patient in the world was treated by endovascular means after practicing with the stent graft procedure on the Angio Mentor on 10 January at the University Hospital of Ghent, Belgium. It was presented at the Leipzig Interventional Course (LINC) on 25 January 2012.

Vermassen said that Ghent will be leading a multicentre trial to see what impact the dummy run has on patient and team outcomes. He said it may be possible to fine-tune using the simulator, investigating areas if this software may aid in matching the endograft to the aneurysm, if it is worth rehearsing the complete procedure and if the entire team should be present.

“Being able to rehearse a complicated procedure like this means we are able to minimise any technical and non-technical difficulties before the patient reaches theatre, making surgery not only quicker but more importantly safer,” he said.

Left: EVAR real case Right: EVAR rehearsal

 

Carotid vasculature modeling from patient CT angiography studies for interventional procedures simulation.

Freiman M, Joskowicz L, Broide N, Natanzon M, Nammer E, Shilon O, Weizman L, Sosna J.

Int J Comput Assist Radiol Surg. 2012 Feb 29. [Epub ahead of print]

School of Engineering and Computer Science, The Hebrew University of Jerusalem, Jerusalem, Israel,

OBJECTIVE: A practical method for patient-specific modeling of the aortic arch and the entire carotid vasculature from computed tomography angiography (CTA) scans for morphologic analysis and for interventional procedure simulation.

MATERIALS AND METHODS: The method starts with the automatic watershed-based segmentation of the aorta and the construction of an a-priori intensity probability distribution function for arteries. The carotid arteries are then segmented with a graph min-cut method based on a new edge weighting function that adaptively couples voxel intensity, intensity prior, and local vesselness shape prior. Finally, the same graph-cut optimization framework is used to interactively remove a few unwanted veins segments and to fill in minor vessel discontinuities caused by intensity variations.

RESULTS: We validate our modeling method with two experimental studies on 71 multicenter clinical CTA datasets, including carotid bifurcation lumen segmentation on 56 CTAs from the MICCAI’2009 3D Segmentation Challenge. Segmentation results show that our method is comparable to the best existing methods and was successful in modeling the entire carotid vasculature with a Dice similarity measure of 84.5% (SD = 3.3%) and MSSD 0.48 mm (SD = 0.12 mm.) Simulation study shows that patient-specific simulations with four patient-specific models generated by our segmentation method on the ANGIO Mentor(TM) simulator platform are robust, realistic, and greatly improve the simulation.

CONCLUSION: This constitutes a proof-of-concept that patient-specific CTA-based modeling and simulation of carotid interventional procedures are practical in a clinical environment

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Patient-Specific Simulation for Endovascular Procedures: Qualitative Evaluation of the Development Process

Willaert WI, Aggarwal R, Nestel DF, Gaines PA, Vermassen FE, Darzi AW, Cheshire NJ; European Virtual Reality Endovascular Research Team, EVEResT.
Department of Biosurgery and Surgical Technology, St. Mary’s Hospital, Imperial College, London, UK.

Int J Med Robot. 2010 Jun; 6(2):202-10.

Background: Recent advancements in simulation permit patient-specific rehearsal of carotid artery stenting procedures. This study evaluates the feasibility of transferring patient-specific CT data into the simulator, creating a 3D reconstruction and performing a rehearsal. The face validity of the model was assessed.

Methods/Results: By thematic analysis of qualitative data, an algorithm was generated, focusing on simulation set-up, time of data transfer, software/compatibility issues and problem-solving strategies. The face validity of the simulated case was evaluated by 15 expert interventionalists: realism (median 4/5), training potential (median 4/5) and pre-procedure rehearsal potential for challenging CAS cases (median 4/5) were rated highly.

Conclusions: Setting up a procedure rehearsal is feasible and reproducible for different patients in different hospital settings without major software compatibility issues. The time to create a 3D reconstruction of patient-specific CT data is a major factor in the total time necessary to set up a rehearsal. The face validity is highly rated by experts. (c) 2010 John Wiley & Sons, Ltd.

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Simulation Case Rehearsals for Carotid Artery Stenting

Hislop SJ, Hedrick JH, Singh MJ, Rhodes JM, Gillespie DL, Johansson M, Illig KA.

Division of Vascular Surgery Department of Surgery, University of Rochester Medical Center, Rochester, NY, USA.

Eur J Vasc Endovasc Surg. 2009 Dec;38(6):750-4. Epub 2009 Oct 3.

A case series of 5 patients is presented assessing the utility of simulation case rehearsals of individual patients for carotid artery stenting on an endovascular simulator. Simulated and operative device dimensions were similar. Results of subjective surveys indicated that face and content validity were excellent. The simulations predicted difficulty with vessel cannulation, however had difficulty predicting post-stent changes in bifurcation angulation. Our experience suggests that it may be feasible to use patient-specific CTA-derived data in the creation of a realistic case rehearsal simulation. The overall utility of this concept, including cost-benefit analysis, has yet to be determined.

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The following abstract was presented and won the 1st prize at the 36th Annual VEITH Symposium November 18 – 22, 2009; New York, USA

Virtual Reality PROcedure Rehearsal Can Enhance the Choice of Endovascular Tools for Carotid Artery Stenting Procedures

Willaert Willem MD 1, Aggarwal Raj MD PhD 1, Van Herzeele Isabelle MD 2, O’Donoghue Kevin BSc 1, Kabbar Marwan 2, Gaines Peter FRCP FRCR 3, Vermassen Frank MD PhD 2, Darzi Ara KBE MD FRCS 1, Cheshire Nick MD, FRCS 1

1Department of Biosurgery and Surgical Technology, Imperial College London, St. Mary’s Hospital, London, United Kingdom, 2Department of Thoracic and Vascular Surgery, Ghent University Hospital, Ghent, Belgium, 3Sheffield Vascular Institute, Northern General Hospital, Sheffield, United Kingdom

Introduction: Patient-specific simulated rehearsal of the carotid artery stenting procedure (CAS) allows incorporation of patient-specific CT data into the simulation software. This enables the interventionalist to evaluate the effect of different endovascular material and fluoroscopy angles prior to performing the real procedure. Procedure rehearsal is a technological advance with potential benefits to patients undergoing complex endovascular procedures.

Aim: This study aimed to evaluate whether patient-specific, procedure rehearsal of a CAS procedure has an influence on tool selection and the use of fluoroscopy. Secondary aims were to evaluate the face validity of this technology and to evaluate if the potential benefit is influenced by the level of CAS experience.

Methods: Endovascular physicians with a varying degree of CAS experience were recruited and divided into three groups: inexperienced (5-20 CAS), moderately (21-50 CAS) and highly experienced in CAS (>50 CAS procedures). A 3D model was created of an actual patient with the PROcedure TM rehearsal studio software. Following case note and CT angiographic review of a real patient case, all participants rehearsed this patient-specific CAS procedure on the AngioMentor TM Express simulator. Preoperative and postoperative questionnaires registered tool and fluoroscopy preferences in a stepwise fashion for this specific CAS procedure. A questionnaire rated face validity, training potential and pre-procedure potential on a Likert scale from 1 (poor) to 5 (excellent). Results: Thirty three endovascular physicians with varying degrees of CAS experience participated: inexperienced (n=11), moderately (n=7) and highly experienced (n=15). For all participants 98 of a possible 363 changes (27%) were observed from pre- to post-case questionnaires. This was most notable for optimal fluoroscopy C-arm position 17/33 (52%), chosen guide wire to introduce the sheath in the common carotid artery 15/33 (46%), choice of selective catheter 13/33 (39%) or guiding catheter (or sheath) 12/33 (36%) and balloon dilatation strategy 10/33 (30%). Although modifications in tool preferences were more apparent in the inexperienced group, these alterations were not significantly influenced by level of CAS experience (p>0.05) Face validity of the model, training potential and pre-procedure potential were rated high by the interventionalists and all measured a median of 4.

Conclusion: Patient-specific simulated rehearsal of a complex endovascular procedure strongly influences tool selection and fluoroscopy. This influence seems irrespective of the prior experience level with CAS. This technology requires further investigation with respect to a potential reduction in the use of endovascular material and X-ray exposition and with respect to improved outcomes in the clinical setting.

Real Case Virtual Reality Training Prior to Carotid Artery Stenting

Roguin A, Beyar R.

Department of Cardiology, Rambam Medical Center, B. Rappaport-Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.

Catheter Cardiovasc Interv. 2009 Jul 15.
Background: The majority of procedural training especially in interventional cardiology, still occurs on patients with direct mentoring by experienced physicians during an actual clinical procedure. In recent years there is an increase use of simulators especially for carotid artery stenting. However, most simulators use “generic” predefined cases.

Methods and Result: We report here a simulation done on data of a real patient prior to intervention. The patient’s specific carotid anatomy was modeled using CTA on an endovascular simulator. Pre-procedure patient-specific case rehearsal accurately predicted procedure experience.

Conclusions: A case rehearsal prior to an intervention may be useful in the planning and execution of carotid artery stenting. The use of patient specific simulation helps with planning of procedure and device selection, and may lead to use of less contrast and radiation, and shorter procedure duration. These may benefit the patient with increased success and lower complication rates.

The following abstract was presented at the Annual Meeting of the Society for Vascular Surgery (SVS) June 11-14, 2009 Denver, USA

Patient Specific Endovascular Simulation Influences the Material Selection of All Interventionalists Performing a Carotid Artery Stent Procedure

Willem Willaert1, Rajesh Aggarwal1, Isabelle Van Herzeele2, Kevin O’Donoghue1, Marwan Kabbar2, Peter Gaines3, Frank Vermassen2, Ara Darzi1, Nick Cheshire1.
1Department of Biosurgery and Surgical Technology, Imperial College London, London, United Kingdom; 2Department of Thoracic and Vascular Surgery, Ghent University Hospital, Ghent, Belgium; 3Sheffield Vascular Institute, Northern General Hospital, Sheffield, United Kingdom

Objective: Virtual reality endovascular simulation permits the integration of patient-specific data into the software and allows rehearsal of carotid artery stent (CAS) procedures before the ‘real’ intervention. The aim of this study is to evaluate the effect of this technology on physicians’ attitudes towards the selection of endovascular materials necessary for a CAS procedure.

Methods: Twenty eight interventionalists were recruited and divided into three groups: highly experienced (_50 CAS procedures) n_11, moderately experienced (21- 50 CAS) n_6 and inexperienced in CAS (5- 20 CAS) n_11. After review of the CT scan of a type II arch with a tortuous common carotid artery (CCA), all subjects performed the same virtual CAS procedure. Before and after the intervention the choice of endovascular tools and fluoroscopy angles were documented with a questionnaire. Quantitative metrics (procedure time, fluoroscopy time, number of cineloops and amount of contrast given) were recorded by the simulator. Participants also rated the realism and training potential of patient specific simulation on a Likert scale from 1 (poor) to 5 (excellent).

Results: For the 28 participants a total of 252 potential changes were identified. In general 76 changes were observed (33%). Change was most notable in the type of guide wire chosen to exchange a sheath 15/28 (54%), optimal C-arm position 13/28 (46%), choice of selective catheter 12/28 (43%), selection of a sheath or guiding catheter 10/28 (36%) and balloon dilatation strategy 10/28 (36%). The type of embolic protection device 3/28 (11%), position of exchange for a guiding catheter or sheath 3/28 (11%) and the sort of guide wire to cannulate the CCA 1/28 (4%), were altered less frequently. Statistical analysis showed that the degree of change was not influenced by the level of operator experience (P_0.05). The quantitative metrics did not differ significantly between the groups (P_0.05). Participants rated the simulator high for realism (median 4) and for the potential to be used as a pre-procedural training tool (median 4).

Conclusions: Patient specific simulation remarkably influences the endovascular tool selection and C-arm positions in CAS procedures, irrespective of the level of endovascular CAS experience.

The following abstract was presented at the Annual Meeting of the EuroPCR May 19,-22, 2009 Denver, USA

Understanding Patient-Specific Virtual Reality Endovascular Simulation

Willem Willaert MD, Rajesh Aggarwal PhD, MRCS, Isabelle Van Herzeele MD, Kevin O’Donoghue Bsc, Marwan Kabbar, Peter Gaines FRCP,FRCR, Frank Vermassen MD, PhD, Ara Darzi KBE, MD, FRCS and Nick Cheshire MD, FRCS.
1Department of Biosurgery and Surgical Technology, Imperial College London, London, United Kingdom. 2Department of Thoracic and Vascular Surgery, Ghent University Hospital, Ghent, Belgium. 3Sheffield Vascular Institute, Northern General Hospital, Sheffield, United Kingdom.

Aims: Recent advancements in endovascular simulation permits patient-specific rehearsal of carotid artery stenting procedures. This study aimed to evaluate the feasibility of transferring patient-specific CT data into the simulator software and creating a 3D reconstruction and to evaluate the feasibility of performing a subsequent rehearsal on the simulator. The face validity of the model was also assessed.

Methods/Results: By thematic analysis of qualitative data (coded transcripts and field notes of 30 simulated cases), an algorithm was generated describing the process of Procedure Rehearsal. The analysis focused on simulation set up, ease and time of data transfer, software/compatibility issues and problem-solving strategies. The face validity of the simulated case was evaluated by 15 expert interventionalists using a questionnaire with a Likert scale from 1 (poor) to 5 (excellent). Realism (median 4), training potential (median 4) and pre-procedure rehearsal potential (median 3) were rated high.

Conclusion: Setting up a Procedure Rehearsal is feasible and reproducible for different patients in different hospital settings without major software compatibility issues. The time to create a 3D reconstruction of patient specific CT data is a major factor in the total time necessary to set up a rehearsal. The face validity is highly rated by experts.

The following abstract was presented at the Annual Meeting of the SITE, May 7- 9 2009 in Barcelona.

Patient Specific Rehearsal on a Virtual Reality Simulator Influences the Behavior of Interventionalists During a Carotid Artery Stenting Procedure

Willem Willaert MD, Rajesh Aggarwal PhD, MRCS, Isabelle Van Herzeele MD, Peter Gaines FRCP,FRCR, Frank Vermassen MD, PhD and Nick Cheshire MD, FRCS.

1Department of Biosurgery and Surgical Technology, Imperial College London, London, United Kingdom. 2Department of Thoracic and Vascular Surgery, Ghent University Hospital, Ghent, Belgium. 3Sheffield Vascular Institute, Northern General Hospital, Sheffield, United Kingdom.
Introduction: Patient-specific simulated rehearsal of complex endovascular interventions allows incorporation of patient-specific CT data into the simulation software, enabling the interventionalist to evaluate the use of the C-arm, different endovascular tools and the optimal access strategy prior to performing the real procedure. It is a technological advance with potential benefits to patients undergoing carotid artery stenting (CAS) procedures.

Objectives: This study aimed to evaluate whether patient-specific rehearsal of a CAS procedure has an influence on tool selection and the use of fluoroscopy. Secondary aims were to evaluate the face validity of this technology and if the potential benefit of patient-specific rehearsal is influenced by the level of CAS experience.

Materials: Endovascular physicians with a varying degree of CAS experience were recruited and divided into three groups: inexperienced (5-20 CAS), moderately (21-50 CAS) and highly experienced in CAS (>50 CAS procedures). A 3D model was created of an actual patient with the PROcedureTM rehearsal studio software. Subsequently all participants rehearsed this patient-specific CAS procedure on the AngioMentorTM Express simulator. Preoperative and postoperative questionnaires registered tool and fluoroscopy preferences in a stepwise fashion for this specific CAS procedure. A questionnaire rated face validity, training potential and pre-procedure potential on a Likert scale from 1 (poor) to 5 (excellent).

Metholodogy: Following case note and CT angiographic review of a real patient case, subjects performed a familiarization virtual iliac procedure. Thereafter they proceeded to the CAS procedure. Endovascular tool requirements, fluoroscopic angles and the face validity were recorded.

Results: Thirty three endovascular physicians with varying degrees of CAS experience participated: inexperienced (n=11), moderately (n=7) and highly experienced (n=15). For all participants 98 of a possible 363 changes (27%) were observed from pre- to post-case questionnaires. This was most notable for optimal fluoroscopy C-arm position 17/33 (52%), chosen guide wire to introduce the sheath in the common carotid artery 15/33 (46%), choice of selective catheter 13/33 (39%) or guiding catheter (or sheath) 12/33 (36%) and balloon dilatation strategy 10/33 (30%). Although modifications in tool preferences were more apparent in the inexperienced group, these alterations were not significantly influenced by level of CAS experience (p>0.05) Face validity of the model, training potential and pre-procedure potential were rated high by the interventionalists and all measured a median of 4.

Conclusion: Patient-specific simulated rehearsal of a complex endovascular procedure strongly influences tool selection and fluoroscopy. This influence seems irrespective of the prior experience level with CAS. This technology requires further investigation with respect to a potential reduction in the use of endovascular material and X-ray exposition and with respect to improved outcomes in the clinical setting.

Patient Specific Simulation Enabling Hands-On Rehearsal of Carotid Stenting

Giora Weisz, Center for Interventional Vascular Therapy, Columbia University Medical Center, New York, NY, USA

EuroIntervention Journal, 2009 March, Volume 4, Number 5 page 684
Introduction: Endovascular procedures like carotid stenting can pose challenges even to experienced interventionists. Tortuous anatomy, complex lesion morphology, and difficult device access can increase procedure time, fluoroscopy exposure, contrast use, and complications.

The New Technology: Simbionix PROcedure Rehearsal Studio™ simulates the interventional environment and allows rehearsal of a complete endovascular procedure on a virtual model of the patient’s specific anatomy. Loading the patient’s CT scan directly into the system generates a digital 3D model of the patient’s clinically relevant anatomy. It generates a simulated interventional suit environment that provides the impression of a real procedure on a real patient. This includes display of the c-arm, visual presentation of fluoroscopic images, reliable tactile feedback of the movement and function of intravascular devices, and interactive hemodynamic effects.

Preliminary Testing: Initial experience with the system demonstrated ease of use, and accurate vascular simulation. Rehearsal of complex cases of carotid stenting gave the operators the opportunity to practice the specific anatomy of the patient and to select the appropriate devices for the specific anatomy of the patient, in advance of the actual intervention. The actual interventional procedures were eventually easier and faster.

Conclusion: Using patient specific simulation with the Simbionix PROcedure Rehearsal Studio™ helps with planning of procedure and device selection, leading to use of less contrast and radiation, and shorter procedure duration. These benefit the patient with increased success and lower complication rates. Virtual rehearsal, derived from patient-specific simulation may increase the demand for the placement of simulators in larger number of institutions.

The following abstract was presented at the New England Society for Vascular Surgery on Oct 5, 2008

Patient Specific Case Rehearsals Using an Endovascular Simulator Prior to Carotid Artery Stenting

Sean J Hislop, MD, Joseph H Hedrick, MD, Michael J Singh, MD, Jeffrey M Rhodes, MD, Joseph P Hart, MD, Marcia Johansson, ACNP, and Karl A Illig, MD

Division of Vascular Surgery, at the Strong Heart and Vascular Center, University of Rochester Medical Center, NY, 14642

Objectives: To determine whether a patient’s specific carotid anatomy can be modeled using CTA on an endovascular simulator and whether preoperative patient-specific case rehearsal accurately predicts operative experience.

Methods: Patients underwent CTA of the arch and carotid circulation. Simbionix Corporation (Lod, Israel) used deidentified CTAs to create simulation files. The surgeon performed the simulated case within 24 hours of the actual procedure. Likert surveys (strongly agree – strongly disagree) were completed assessing face validity, or the degree to which the simulation mimicked real life.

Results: Five patient-specific simulations were performed. The surgeons “strongly agreed” (median score 5/5) that the simulation improved the operative flow, increased patient safety and efficiency of instrument use, assisted in selection of EPD, stent, diagnostic catheter and balloon, decreased overall operative and fluoroscopy time and the amount of contrast used, and that the operative and simulator outcomes were similar. They “agreed” (median score 4/5) that the simulation assisted with vessel access and with wire selection. Face validity was excellent: surgeons “strongly agreed” that the simulator was easy to use, realistically replicated reality, produced realistic imaging and tactile feedback (haptics), realistically replicated patient arch, carotid and lesion anatomy and that it accurately predicted stent dimensions. All simulated EPD, stent, and balloon dimensions matched those used in the operating room. Subjective observations suggested that the simulation predicted difficulty with vessel cannulation but did not accurately model post-stent deployment changes in bifurcation angulation.

Conclusions: These data indicate that patient-specific CTA-derived data can be converted to an endovascular simulator with high face validity. We suggest that case rehearsal prior to an operation may be useful in the planning and execution of carotid artery intervention.