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Trial registered on ANZCTR


Registration number
ACTRN12621000257864
Ethics application status
Approved
Date submitted
11/12/2020
Date registered
10/03/2021
Date last updated
10/03/2021
Date data sharing statement initially provided
10/03/2021
Type of registration
Prospectively registered

Titles & IDs
Public title
Graft Patency and Clinical Outcomes Following Coronary Artery Bypass Grafting with Instrumented Radial Arteries
Scientific title
Graft Patency and Clinical Outcomes Following Coronary Artery Bypass Grafting with Instrumented Radial Arteries
Secondary ID [1] 302572 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Coronary Artery Disease
319450 0
Coronary artery bypass grafting 319451 0
Intrumented radial arteries 319453 0
Condition category
Condition code
Cardiovascular 317422 317422 0 0
Coronary heart disease

Intervention/exposure
Study type
Observational
Patient registry
False
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
This study has two aims:
1. To evaluate the patency of instrumented radial arteries used for CABG, compared to non-instrumented radial arteries, internal mammary arteries and saphenous vein grafts.
2. To evaluate the clinical outcomes of patients undergoing CABG with an instrumented radial artery, compared to those without an instrumented radial artery.

Initially, patients will be recruited from the hospitals cardiac surgery database. Patients in the database who underwent surgery between January 2015 and December 2019 will be reviewed. Only those patients who had coronary artery bypass grafting with bilateral radial arteries will be included. For eligible patients, baseline data will be collected retrospectively from the hospital medical records and the hospital cardiac surgery database. Further data may be retrieved from other medical practitioners involved in their care. Information collected includes medical history, investigation results, pre-operative data, operation records, post operative data and longer term outcomes (see below for specific outcome data). Following review of the medical records, patients will be telephoned to seek clarification and further information as required. This will be a one off phone call, and will include facilitating completion of a Seattle Angina Questionnaire (short form, SAQ-7).

The second part of the study, known as "patency follow up", involves conducting CT-coronary angiograms on a specific subset of patients. These patients are those who have an instrumented radial artery used as a coronary artery bypass graft. During the above "clinical follow up" phone call, patients will be assessed as to whether they are eligible for the "patency follow up" arm of the study. Eligible patients (see inclusion and exclusion criteria elsewhere in this document) will undergo a CT-coronary angiogram to evaluate the patency of the coronary artery bypass grafts. If eligible and willing to participate, patients will expect to undergo the CT-coronary angiogram within approximately 6-weeks. This scan will occur in Heidelberg, Victoria at I-MED Warringal and it is expected that the participant would require to be present for 1.5 - 2 hours duration.
Intervention code [1] 318862 0
Not applicable
Comparator / control treatment
Aim 1: The main comparator to the instrumented radial artery graft will be the contralateral non-instrumented radial artery graft, Instrumented radial artery graft patency will also be compared to the left internal mammary artery graft and saphenous vein graft patency.
Aim 2: The comparator group is those without an instrumented radial artery.
Control group
Active

Outcomes
Primary outcome [1] 325457 0
Aim 1 (patency follow up): Patency (or graft failure rate) of the instrumented radial artery grafts, compared to the non-instrumented radial artery graft.
- Patients in the study cohort who had an instrumented radial artery used as a graft will be eligbile for this part of the study.
- Each instrumented radial graft will be assessed by CT-coronary angiography (CTCA) by two certified CTCA readers, both blinded to the location of the instrumented RA. Graft stenoses will be assessed as per the CAD-RADS stenosis guidelines (0% stenosis, 1-24% stenosis, 25-49% stenosis, 50-69% stenosis, 70-99% stenosis, or occluded) and whether "string sign" is present.
- Graft patency will be defined as the absence of string sign, occlusion, or stenosis 70% or more. That is, graft failure is defined as total occlusion, stenosis of 70% or more, or string sign.
Timepoint [1] 325457 0
Aim 1 (patency follow up):
- Patients will undergo CT-coronary angiography at varying time points. Patients will be followed up at least one year following CABG, with a range of 1-5 years. Each patient will undergo one CT-coronary angiogram. The mean mean follow up is anticipated to be approximately 2.5-3 years.
Primary outcome [2] 325458 0
Aim 2 (clinical follow up):
- Composite outcome: all-cause mortality, non-fatal myocardial infarction, repeat revascularization, hospitalization for heart failure or unstable angina.
- This outcome will be assessed by review of medical records and phone call to participating patients. Verification of history and further clinical information may be retrieved from treating medical professionals following consent.
Timepoint [2] 325458 0
Aim 2 (clinical follow up):
- Clinical follow up will be assessed both at 12 months, and at longest available follow up.
Secondary outcome [1] 389808 0
Aim 2 (clinical follow up):
- Symptom / angina status. This will be assessed via two different assessment tools;
- Patient assessed - Using the Seattle Angina Questionnaire Short Form (SQQ-7).
- Clinican assessed - Canadian Cardiovascular Society (CCS) angina grade.
Timepoint [1] 389808 0
Aim 2 (clinical follow up):
- at time of follow up (between 1 and 5 years post surgery)
Secondary outcome [2] 391614 0
Aim 2 (clinical follow up):
- Non-fatal stroke. This will be assessed via phone call with the participant, and verified via hospital medical records, as able.
Timepoint [2] 391614 0
12 months and longest available follow up
Secondary outcome [3] 391615 0
Aim 2 (clinical follow up):
- Cardiovascular death. This will be assessed via the hospital medical record, or from other treating health practitioners.
Timepoint [3] 391615 0
At 12 months and at longest available follow up
Secondary outcome [4] 391616 0
Aim 2 (clinical follow up):
- All-cause mortality
- This will be assessed via phone call with the participant, and verified via hospital medical records, as able.
Timepoint [4] 391616 0
At 12 months and at longest available follow up
Secondary outcome [5] 392625 0
Aim 2 (clinical follow up):
- non-fatal myocardial infarction.
- This will be assessed via phone call with the participant, and verified via hospital medical records, as able.
Timepoint [5] 392625 0
At 12 months and at longest available follow up
Secondary outcome [6] 392626 0
Aim 2 (clinical follow up):
- Repeat revascularisation.
- This will be assessed via phone call with the participant, and verified via hospital medical records, as able.
Timepoint [6] 392626 0
At 12 months and longest available follow up.
Secondary outcome [7] 392627 0
Aim 2 (clinical follow up):
- Hospitalization for heart failure or unstable angina.
- This will be assessed via phone call with the participant, and verified via hospital medical records, as able.
Timepoint [7] 392627 0
At 12 months and longest available follow up.

Eligibility
Key inclusion criteria
Whole study:
Adult patients aged 18 years or older who underwent coronary artery bypass grafting between 2015-2019 using bilateral radial arteries as conduits.

For the Patency arm of the study (Aim 1):
Patients who underwent CABG with an instrumented radial artery.
Minimum age
18 Years
Maximum age
No limit
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Patency follow up (Aim 1)
- Stage 4 or more chronic kidney disease.
- Patients who have had either an invasive coronary angiogram or CT coronary angiogram following surgery.
- The CABG operation record does not specify the location of each radial artery (ie which RA is grafted to which native vessel).
- Allergy to contrast agent.
- Unable to sufficiently control heart rate to perform scan or contraindication to metoprolol administration if required

Clinical follow up (Aim 2)
- Unable to provide consent

Study design
Purpose
Natural history
Duration
Longitudinal
Selection
Defined population
Timing
Both
Statistical methods / analysis
Analysis will be using a mixed effect logistic regression model for patency follow up (aim 1), and a logistic regression model for clinical follow up (aim 2). Clinical follow up will be analysed at 12-months, and at longest available follow up by time to event analysis.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
VIC
Recruitment hospital [1] 17850 0
Austin Health - Austin Hospital - Heidelberg
Recruitment postcode(s) [1] 31707 0
3084 - Heidelberg

Funding & Sponsors
Funding source category [1] 307004 0
Charities/Societies/Foundations
Name [1] 307004 0
Austin Medical Research Foundation
Address [1] 307004 0
145 Studley Road,
Heidelberg,
Victoria,
3084
Country [1] 307004 0
Australia
Primary sponsor type
Individual
Name
A/Prof Omar Farouque
Address
Austin Health
145 Studley Rd
Heidelberg
Victoria. 3084
Country
Australia
Secondary sponsor category [1] 307577 0
None
Name [1] 307577 0
Address [1] 307577 0
Country [1] 307577 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 307136 0
Austin Health Human Research Ethics Committee
Ethics committee address [1] 307136 0
Austin Health
145 Studley Road
Heidelberg
Victoria 3084
Ethics committee country [1] 307136 0
Australia
Date submitted for ethics approval [1] 307136 0
31/08/2020
Approval date [1] 307136 0
19/02/2021
Ethics approval number [1] 307136 0

Summary
Brief summary
Our study is designed to evalute the patency rates and clinical outcomes in patients using an instrumented radial artery for coronary artery bypass grafting. An instrumented radial artery is one where an invasive coronary angiogram has been performed by inserting wires and catheters through the radial artery in to the heart. It is possible that this procedure may injure the radial artery and make it less useful as a bypass graft.

In recent years, there has been an increasing preference for using arteries as bypass grafts in coronary artery bypass grafting, and invasive coronary angiograms are now routinely performed via the radial artery. Therefore, there is an increasingly common scenario of deciding whether the instrumented radial artery should be used as a bypass graft, and there is very little evidence to guide this decision.

Our study will retrospectively identify patients who underwent CABG with instrumented radial arteries. We will then compare their outcomes to patients who did not have an instrumented radial artery used as a graft. Additionally, a subset of patients will undergo CT coronary angiograms. CT coronary angiograms look for narrowings in the blood vessels that supply the heart, without the need for catheters to be inserted. We will compare the narrowings / blockages in the instrumented radial artery with non-instrumented radial arteries, internal mammary arteries and saphenous vein grafts to determine whether instrumented radial arteries become blocked more quickly.

Our hypothesis is that instrumented radial arteries have lower patency rates, and therefore higher rates of graft failure, then non-instrumented radial arteries, when used for coronary artery bypass grafting
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 106158 0
A/Prof Omar Farouque
Address 106158 0
Department of Cardiology
Austin Health
145 Studley Road
Heidelberg
Victoria
3084
Country 106158 0
Australia
Phone 106158 0
+61 03 9496 3034
Fax 106158 0
Email 106158 0
omar.farouque@austin.org.au
Contact person for public queries
Name 106159 0
Dr Garry Hamilton
Address 106159 0
Department of Cardiology
Austin Health
145 Studley Road
Heidelberg
Victoria
3084
Country 106159 0
Australia
Phone 106159 0
+61 03 9496 5000
Fax 106159 0
Email 106159 0
garry.hamilton@austin.org.au
Contact person for scientific queries
Name 106160 0
Dr Garry Hamilton
Address 106160 0
Department of Cardiology
Austin Health
145 Studley Road
Heidelberg
Victoria
3084
Country 106160 0
Australia
Phone 106160 0
+61 03 9496 5000
Fax 106160 0
Email 106160 0
garry.hamilton@austin.org.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
What supporting documents are/will be available?
No other documents available
Summary results
No Results