Holo CTO Proctoring Study
Conditions: Percutaneous Coronary Intervention, Chronic Total Occlusion of Coronary Artery
Sponsor: Sorlandet Hospital HF

Site protocol v2 
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Department of Cardiology 
Sørlandet Hospital, Arendal 
 
 
                                                            
                                                                                                  
        Holo CTO proctoring study 
                                                                                                                               
           Norwegian feasibility study on the use of mixed reality technology in CTO proctoring 
           NCT number: not available  
             
 
            Academic trial by Sørlandet Hospital Arendal , Arendal, Norway 
                                                                                                                                
                                                                                                                                  
Slobodan Calic, MD, primary investigator 
Christian Hesbø Eek,MD,PhD, coordinating investigator 
 
Sørlandet Hospital Arendal  
Department of Cardiology/PCI center Arendal 
Lundsiden,4604 Kristiansand, Norway 
 
 
 
 
 
 
 
 
 
 

Site protocol v2 
17.10.2021                                                                                                                                                                                               
 
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Department of Cardiology 
Sørlandet Hospital, Arendal 
 
Holo CTO proctoring study 
Site protocol 
Slobodan Calic MD, primary investigator 
Christian Eek MD, PhD, coordinating investigator 
Sørlandet Hospital Arendal 
Department of cardiology 
Study group  
Slobodan Calic, MD, Sørlandet Hospital Arendal 
Christian Eek, MD, PhD, Oslo University Hospital, Rikshospitalet 
Jarle Jortveit , MD, PhD, Sørlandet Hospital Arendal 
Jahn Otto Andersen, CTO, Master of science, HoloCare AS 
Participating centres  
Department of Cardiology /PCI centre, Sørlandet Hospital Arendal 
Dr Slobodan Calic 
Department of Cardiology, Rikshospitalet, Dr Christian Eek 
Technical support  
HoloCare  AS Oslo 
Sopra Steria, Oslo 
1. Background 
1.1 CTO 
Chronic total occlusion (CTO) of one or more coronary vessels are relatively common 
findings in coronary angiography. One large-scale registry showed that up to 20% of patient 
with coronary artery disease had a CTO. (1) Compared to percutaneous coronary intervention 
(PCI) of non-occluded vessel, CTO PCI has a lower success rate, and a higher complication 
rate. They are time consuming and more complex, and several different strategies and various 
equipment is applied. This suggests more systematic procedure planning, consistent approach 
and a need for systematic training.(2) At most institutions, CTO PCI is performed by two 
operators, enabling discussions of findings and strategy during the procedure. Although only 
one operator at a time can be “hands on” during CTO PCI, large amounts of information is 
processed during the procedure, and unexpected findings and difficulties often occur. At our 
institution, a single operator performs CTO procedure. Procedures are often pre-planned  
 

Site protocol v2 
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Department of Cardiology 
Sørlandet Hospital, Arendal 
 
together with an external operator.  This is helpful, but does not allow for discussion and 
adjustments during the intervention. We believe that CTO PCI performed in a team will be 
more robust and accurate than that of single operator working alone. 
 
1.2 CTO Proctoring 
Several studies have showed a relationship between physician volume and outcomes of 
percutaneous coronary interventions (PCI) with better outcomes reported for high volume 
operators when compared with low volume operators.(3) Proctoring in medicine is related to 
better outcomes. Specifically, in CTO PCI systematic proctoring has demonstrated improved 
success rates, and an increased ability to treat lesions that are more complex. (4). Most likely, 
proctoring together with operator volume is one of the foundations to the introduction and 
execution of CTO procedures. Proctoring traditionally involves an expert operator (proctor), 
visiting the institution, performing the procedure together with the local operator. This 
involves increased cost, and current travel restrictions makes traditional one-on-one 
proctoring challenging. To our knowledge, the feasibility of real time proctoring using 
modern web based communication tools has never been assessed in interventional cardiology.  
1.3 Microsoft HoloLens in proctoring 
This study aims to evaluate the Microsoft HoloLens as a potential platform in proctoring and 
effective real time communication between PCI operators located at different geographical 
locations. The proctor and the local operator interact using a head mounted mixed reality 
(MR) display, enabling the proctor to see the same image as the operator, from any distanced 
location.   
 
1.4 Mixed reality in medicine  
The Microsoft HoloLens is a mixed reality head mounted display, which allows users to 
interact with their environment using a Hologram. Mixed reality (MR) like augmented reality 
(AR) and virtual reality (VR) are defined like extended reality. Extended reality describes the 
spectrum of virtuality continuum (5). While VR are interactions fully immersed in a synthetic 
environment, AR allows the user to see their native environment while placing 2D or 3D 
images within true background. Mixed reality is a new class of experience and allows 3D 
visualization of imaged data and contact-free interaction with the data in the sterile 
environment allowing the operator to have increased control and manipulation over digital 
objects without obstructing the normal visual field. At  the same time this technology can 
provide a possibility of collaboration between operators in a unique way, which can simulate 
the interaction as if working in a team in the same non-virtual operating space.(6) 
 
 
 
 

Site protocol v2 
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Department of Cardiology 
Sørlandet Hospital, Arendal 
 
1.5 Microsoft HoloLens in medicine 
To our knowledge, this device has never been used in clinical practice connected to 
interventional cardiology but HoloLens and similar devices  have been explored within 
surgical innovation (7), education in medicine (8) to treat anxiety during procedures (9) and in 
stroke rehabilitation .(10) 
In cardiological practice, mixed reality devices have been used in intraprocedural 
visualization connected to electrophysiology procedures (11) and in pediatric cardiology (12), 
(13). 
We believe that communication and interaction through HoloLens or similar devices can be 
especial useful nowadays in a pandemic. There is an increasing interest in this subject and we 
expect that telemedicine and virtual interaction are going to play  significant roles in the 
future of medicine, particularly in situations like the current health crisis. (14)  
 
2. Study objective 
2.1 Primary objective 
Assess Microsoft HoloLens  as an interactive communication device in remote proctoring, 
and enhancement of teamwork in complex CTO procedures. 
2.2 Secondary objective 
a) To assess image quality, sound quality, multitasking, comfort, sterility, practicality, spatial 
awareness and possibility of communication with assisting nurse. 
b) Can use of HoloLens in CTO procedures increase effectiveness compared with 
conventional way of communication between operator and distanced proctor/co-operator  
c) Advantage of communication with HoloLens compared with traditional communication 
tools. 
d) To asses feasibility of using HoloLens in invasive cardiology procedures 
e) Does application of HoloLens technology cause limitations, including loss of spatial 
awareness, spatial disorientation, cabling, battery life and device discomfort. 
f) Does interaction between operator and proctor affect procedural endpoints like contrast 
volume, procedure time, fluoroscopy time, costs and procedural success 
 
 
 

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Department of Cardiology 
Sørlandet Hospital, Arendal 
 
 
3. Methods 
3.1 Design 
Feasibility study to asses effectiveness of Microsoft HoloLens as an interactive 
communications tool in CTO PCI procedures. 
3.2 Patients 
Consecutive patients are included based on the following criteria: 
3.2.1 Inclusion criteria 
3.2.1.1 Clinical inclusion criteria 
 • Stable angina pectoris, or dyspnoea as an angina equivalent 
• Age ≥18 yrs. 
• Able to provide written informed consent 
3.2.1.2 Angiographic inclusion criteria  
• One or more completely occluded coronary arteries with Thrombolysis In Myocardial 
Infarction (TIMI) flow 0. 
 •An estimated occlusion duration of at least 3 months 
3.2.1.3 Myocardial viability 
•  Absence of Q-wave in ECG leads corresponding to the occluded vessel, or documented 
viability of the main territory by MRI or echocardiography 
3.2.1.4 Procedural inclusion criteria  
• Clinical indication for CTO PCI regardless of operative technique  
3.2.2 Exclusion criteria  
• STEMI within 72 hours 
•Cardiogenic shock  
•Active bleeding or coagulopathy 
• Life expectancy < 2 years  
•Relevant allergies (aspirin, clopidrogrel, ticagrelol, contrast compounds)  
•Severe peripheral artery disease  
•Clinical unstable angina 
 

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Department of Cardiology 
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3.3 Study process 
Study will be conducted by two participants where one is defined as expert or proctor and the 
other as operator who will perform the CTO procedure. Operator carries out the procedure in 
our institution while expert is located 300 km away. The plan is to conduct ten CTO 
procedures where the operator uses Hololens during the procedure and communicates with the 
proctor from the beginning to the end of procedure. Expert uses conventional laptop computer 
connected to Hololens to communicate and guide operator. 
Guiding is performed by communication (sound) and Holographic interaction through 
Remote Assist software or similar Hololens applications. All participants are trained how to 
operate Hololens. 
3.4 Statistics 
3.4.1 Statistical analyses will be performed in IBM SPSS for Windows (IBM Corp., Armonk, 
NY, USA). Values will be presented as mean ± standard deviation, median (interquartile 
range) or no (%) as appropriate. 
 
3.5 Data management 
Each participant will be given a unique study subject number. A list of participating patients 
and their respective study numbers will be kept in a secure place in a locked office. Patient 
data will be stored in a de-identified manner in a secure database.  
 
 
4. Ethical aspects 
4.1 This study is conducted in accordance with the protocol, applicable regulatory 
requirements and the declaration of Helsinki. The primary investigator has the responsibility 
to obtain approval of the study protocol, the patient information and the informed consent.  
4.2 Risks, side effects, advantages and disadvatanges in participating in the study  
Complex CTO PCI is in itself associated with decreased success rate and higher complication 
risk compared to ordinary PCI in non-occluded vessels. This study group finds no reason to 
believe there should be safety concerns connected to the use of Hololens guiding as by the 
described study protocol. The operator who will perform procedures is highly experienced 
with large volume of CTO procedures and treatment is based on proven treatment techniques. 
We are confident that interaction between operator and proctor during the CTO PCI may have 
differentiating potential in terms of procedural outcome due to complexity of CTO and great 
variation of techniques. In the case of disturbance or operators discomfort with device, the 
operator will simply remove device and continued procedure in the traditional fashion. We do 
not see ethical problems in using Hololens in CTO PCI procedures.  

Site protocol v2 
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Department of Cardiology 
Sørlandet Hospital, Arendal 
 
 
5. Patient information and informed consent 
Patients will get written information about the study. Informed consent for participation in the 
study will be obtained from all patients. The patients will be informed that taking part is 
entirely voluntarily and that they can withdraw for study whenever they want. Withdrawal, or 
refusal to participate, will not influence treatment. Originals of signed consent forms will stay 
at the hospital and the patient will get a copy. It is the responsibility of investigators to ensure 
that informed consent has been acquired.  
6. Biological material  
  
Biological material will not be drawn or stored in the study  
7. Enrolment period 
Enrolment is expected to conclude in first quarter of 2022 
8. Publication 
Results will be published in a peer reviewed international cardiovascular journal.  
9. Study group 
A study group is responsible for this protocol, administrates the study implementation and 
progression.  
 
 
 
 
 
 
 
 
 
 
 
 
 

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Department of Cardiology 
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Multicenter Chronic Total Occlusions Registry. J Am Coll Cardiol 2012; 59: 991-7. 
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