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Trial registered on ANZCTR


Registration number
ACTRN12621001203842
Ethics application status
Approved
Date submitted
1/07/2021
Date registered
9/09/2021
Date last updated
9/09/2021
Date data sharing statement initially provided
9/09/2021
Type of registration
Retrospectively registered

Titles & IDs
Public title
The accuracy and reliability of current angiographic assessment methods for identification of significant dissections during endovascular treatment of femoropopliteal arterial disease
Scientific title
The accuracy and reliability of current angiographic assessment methods for identification of significant dissections during endovascular treatment of femoropopliteal arterial disease
Secondary ID [1] 304680 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Peripheral arterial disease 322652 0
Condition category
Condition code
Cardiovascular 320268 320268 0 0
Diseases of the vasculature and circulation including the lymphatic system

Intervention/exposure
Study type
Observational
Patient registry
False
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
This is an observational study to investigate the performance of different methods of assessing post-angioplasty dissection severity during endovascular intervention to treat occlusive lesions in the femoropopliteal arteries. This will include investigation of how the intra-procedural assessment methods relate to one another, the reliability of each method, and which methods are most likely to identify severe dissections, i.e. ones that develop restenosis or require re-intervention.
The incidence of severe dissection post angioplasty will be measured and binary restenosis and re-intervention rates will be assessed based on regular clinical and imaging follow-up.
The endovascular intervention will be performed following standard practice at the host institution by vascular surgeon or interventional radiologist with experience in endovascular therapy.
Treatment decisions related to post-angioplasty dissection will be made at the treating surgeon discretion and will be based on subjective assessment of angiography and intravascular ultrasound (IVUS) imaging as these are standard imaging techniques used routinely during these procedures at the host institution. Dissection severity assessment will be based on evidence of flow limitation and/or residual stenosis at the dissection. The following intra-procedural assessment methods will be used during the endovascular procedure but not be available to the treating surgeon: quantitative vessel analysis (QVA) of pre and post-angioplasty angiography images to measure the reference vessel diameter and maximum residual stenosis; IVUS measurement of reference vessel diameter, minimum lumen area, dissection arc and maximum residual stenosis; pressure gradient (in mmHg) across the treatment zone using a pressure wire; and duplex ultrasound peak systolic velocity ratio (PSVr) across the treatment zone. This data will be collected at the time of procedure and require no input from the participant. The addition of pressure and duplex assessments will add less than 10 minutes to total procedure time (i.e. <10% of the typical total procedure time of 2 hours). Angiography imaging utilises diagnostic x-ray imaging and non-ionic contrast media. This imaging is required for normal treatment and no additional contrast or radiation will be required for this study. There are no risks to use of the IVUS catheter or the pressure wire.
Pre-treatment data collected includes patient demographics, risk factors, relevant patient medical history and assessment of clinical severity (Rutherford score and ankle brachial pressure index). A quality of life assessment tool (AUSVIQOL) will be completed at this time. Total time involved will be no more than 10 minutes. Data collection will be undertaken by one the principal investigator or a research assistant with at least 5 years’ experience in the care of vascular disorders.
Standard clinical assessment and imaging follow-up of patients will be performed at three, six and 12 months after the endovascular procedure. Standard clinical assessment will involve an outpatient assessment by the clinical team, by vascular medical and nursing staff, and completion of the quality of life tool by one the principal investigator or a research assistant with at least 5 years’ experience in the care of vascular disorders.
Imaging assessment will involve a duplex ultrasound scan of the treated limb to assess for evidence of target lesion restenosis (defined as a PSVr greater than or equal to 2.4 in the treatment zone). The duplex scan will to take 30 minutes and is part of the standard surveillance protocol at the host institution. It will be performed by an accredited medical sonographer at a specialist imaging provider (if performed as an out-patient) or by an accredited medical sonographer at Flinders Medical Centre if performed whilst the participant is an in-patient.
Treatment and clinical assessments (both pre and post-procedure) will be performed at Flinders Medical Centre. Out-patient post-treatment duplex will be performed at Flinders Medical Centre or specialist imaging providers in the community.
Data collected of clinical and imaging results will be used to obtain the primary and secondary outcome described in section 4.
Agreement testing to assess the reliability of subjective assessment of dissection severity will be performed. This will be based on the angiographic imaging. The treating surgeon’s subjective assessment of dissection severity will be recorded and compared to the results of three independent blinded observers. The observers will be vascular surgeons employed by Flinders Medical Centre using de-identified images. This will be performed after the procedure and will not require the involvement of participants.
Intervention code [1] 321051 0
Diagnosis / Prognosis
Comparator / control treatment
No control group
Control group
Uncontrolled

Outcomes
Primary outcome [1] 328127 0
Severity of post-angioplasty dissection as identified by the treating surgeon's subjective assessment.of the angiographic imaging. This assessment will be based on the widely recognised subjective criteria of the presence of a dissection with evidence of flow-limitation across the dissection and/or a residual stenosis related to the dissection
Timepoint [1] 328127 0
0 days, as this is collected at time of procedure as this is an intra-procedural measure
Primary outcome [2] 328128 0
Quantitative measure of dissection severity based on the percentage residual stenosis of the site of dissection, as defined by quantitative vessel analysis of angiography images using the formula: percentage residual stenosis= (minimum diameter/reference vessel diameter) x 100,
Timepoint [2] 328128 0
0 days, as this is collected at time of procedure as this is an intra-procedural measure
Primary outcome [3] 328467 0
Quantitative measure of dissection severity based on IVUS measurement of the percentage residual stenosis related to the dissection (using the formula: percentage residual stenosis= (minimum diameter/reference vessel diameter) x 100)
Timepoint [3] 328467 0
0 days, as this is collected at time of procedure as this is an intra-procedural measure
Secondary outcome [1] 397763 0
The level of agreement between three blinded and independent observers of subjective assessment of dissection severity, based on the subjective angiographic imaging criteria of the presence of a dissection with evidence of flow-limitation across the dissection and/or a residual stenosis related to the dissection.
Timepoint [1] 397763 0
Within 12 months of the interventional procedure
Secondary outcome [2] 397764 0
The rate of intra-procedural stenting of post-angioplasty dissection determined by review of medical imaging records
Timepoint [2] 397764 0
0 days, as this is collected at time of procedure as this is an intra-procedural measure
Secondary outcome [3] 397765 0
Evidence of binary restenosis of the treated lesion, defined as a peak systolic PSVr greater than or equal to 2.4 at surveillance duplex ultrasound,
Timepoint [3] 397765 0
3, 6 and 12 months post index procedure
Secondary outcome [4] 399105 0
Quantitative measures of dissection severity based on the presence of a haemodynamically significant stenosis across the dissection, defined by a PW Doppler peak systolic velocity ratio = 2.4. This is a primary outcome measure.
Timepoint [4] 399105 0
0 days, as this is collected at time of procedure as this is an intra-procedural measure
Secondary outcome [5] 399110 0
Evidence of binary restenosis of the treated lesion, defined as a peak systolic PSVr =2.4 at surveillance duplex ultrasound,
Timepoint [5] 399110 0
3, 6 and 12 months post index procedure
Secondary outcome [6] 399111 0
Quantitative measure of dissection severity based on IVUS measurement of the minimum lumen area of residual stenosis related to the dissection. This is primary outcome measure.
Timepoint [6] 399111 0
0 days, as this is collected at time of procedure as this is an intra-procedural measure
Secondary outcome [7] 399112 0
Quantitative measure of dissection severity based on IVUS measurement of the maxiumum
arc of dissection. This is primary outcome measure.
Timepoint [7] 399112 0
0 days, as this is collected at time of procedure as this is an intra-procedural measure
Secondary outcome [8] 399113 0
Quantitative measures of dissection severity based on a significant drop in systolic blood pressure in a distal direction across the dissection, defined as a 10mmHg reduction pressure between a two measurements obtained proximal and distal to the dissection using a pressure wire. This is a primary outcome
Timepoint [8] 399113 0
0 days, as this is collected at time of procedure as this is an intra-procedural measure
Secondary outcome [9] 399114 0
Difference between pre-procedure and post-procedure ankle brachial pressure index measurements of treated limb,
Timepoint [9] 399114 0
3, 6 and 12 months post index procedure
Secondary outcome [10] 399115 0
Target lesion surgical or endovascular revascularisation re-intervention within 12 months of the index procedure based on review of medical records, to treat restenosis (target lesion defined as the treated segment of the femoropopliteal artery of the treated side).
Timepoint [10] 399115 0
12 months post index procedure
Secondary outcome [11] 399116 0
Difference between pre-procedure and post-procedure of quality of life scores, using the Australian specific, validated AUSVIQUOL scoring tool..
Timepoint [11] 399116 0
3, 6 and 12 months post index procedure
Secondary outcome [12] 399117 0
Difference between pre-procedure and post-procedure clincial severity status, as defined the Rutherford score of clinical severity, using the following locally agreed definitions of this internationally recognised method: 0=no claudication, 1=claudication at 500-1000m, 2= claudication at 200-500 m, 3= claudication at 0-200 m, 4=ischaemic rest pain, 5= minor tissue loss, 6= major tissue loss
Timepoint [12] 399117 0
3, 6 and 12 months post index procedure
Secondary outcome [13] 399121 0
The level of agreement between the treating surgeon's subjective assessment of dissection severity and the consensus assessment of the three blinded and independent observers. Consensus will be defined as agreement of at least two observers.
Timepoint [13] 399121 0
Within 12 months of the interventional procedure
Secondary outcome [14] 399911 0
The sensitivity of angiographic diagnosis of dissection compared to the quantitative reference standard of a PSVr greater than or equal to 2.4 obtained with duplex ultrasound
Timepoint [14] 399911 0
At 12 months only.
Secondary outcome [15] 399912 0
The specificity of angiographic diagnosis of dissection compared to the quantitative reference standard of a PSVr greater than or equal to 2.4 obtained with duplex ultrasound
Timepoint [15] 399912 0
At 12 months only.
Secondary outcome [16] 399913 0
The positive predictive value of angiographic diagnosis of dissection compared to the quantitative reference standard of a PSVr greater than or equal to 2.4 obtained with duplex ultrasound
Timepoint [16] 399913 0
At 12 months only.
Secondary outcome [17] 399914 0
The negative predictive value of angiographic diagnosis of dissection compared to the quantitative reference standard of a PSVr greater than or equal to 2.4 obtained with duplex ultrasound
Timepoint [17] 399914 0
At 12 months only.
Secondary outcome [18] 399915 0
The likelihood ratio f angiographic diagnosis of dissection compared to the quantitative reference standard of a PSVr greater than or equal to 2.4 obtained with duplex ultrasound
Timepoint [18] 399915 0
At 12 months only

Eligibility
Key inclusion criteria
All patients undergoing an endovascular interventional revascularization procedure at Flinders Medical Centre for treatment of a stenotic or occlusive lesion in the SFA or popliteal artery.
Minimum age
18 Years
Maximum age
No limit
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
i. Patients who are unable to give informed consent due to language difficulties, or physical and/or mental incapacity
ii. Patients under 18 years of age
iii. Allergy to iodine based contrast media
iv. Very short life expectancy (<6 months)

Study design
Purpose
Natural history
Duration
Longitudinal
Selection
Defined population
Timing
Prospective
Statistical methods / analysis
Testing of difference of continuous data between groups will performed using independent sample t-test or the Mann-Whitney U test depending on whether the distribution approximated normality. Testing of difference in categorical data between groups will be performed using the chi-square test or Fisher’s exact test when a result of =5 is expected in a cell for dichotomous variables.
The relationship between the various diagnostic methods (subjective angiography, QVA, IVUS, pressure gradient and duplex PSVR) will be explored using tests of correlation and agreement.
Diagnostic accuracy of standard angiographic assessment of dissection will be tested by calculating sensitivity, specificity, positive predictive value, negative predictive value and likelihood ratio of this method against the quantitative reference standard of duplex ultrasound PSVr greater than or equal to 2.4.
Reliability of the dissection severity assessments by the three blinded and independent observers will be investigated with agreement testing using the kappa statistic. Agreement between the the treating surgeon's assessment at the time of the procedure the consensus assessment of the blinded observers will also be tested using the kappa statistic..
Kaplan-Meier survival curves will be generated for the clinical outcomes of binary restenosis and re-intervention, using the logrank analysis to test for differences in rates between cases with and without severe dissection. Logistic regression analysis will be used to identify whether any dissection parameters are independent predictors of restenosis or re-intervention.

Recruitment
Recruitment status
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)
SA
Recruitment hospital [1] 19887 0
Flinders Medical Centre - Bedford Park
Recruitment postcode(s) [1] 34588 0
5042 - Bedford Park

Funding & Sponsors
Funding source category [1] 309047 0
Charities/Societies/Foundations
Name [1] 309047 0
The Hospital Research Foundation
Address [1] 309047 0
Level 1, 62 Woodville Road
Woodville, SA 5011
Country [1] 309047 0
Australia
Primary sponsor type
Hospital
Name
Flinders Medical Centre
Address
Department of Vascular and Endovascular Surgery
Flinders Medical Centre
Flinders Drive
Bedford Park SA 5042
Country
Australia
Secondary sponsor category [1] 309988 0
None
Name [1] 309988 0
Address [1] 309988 0
Country [1] 309988 0
Other collaborator category [1] 281898 0
University
Name [1] 281898 0
University of South Australia
Address [1] 281898 0
101 Currie St, Adelaide SA 5001
Country [1] 281898 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 308924 0
Southern Adelaide Clinical Human Research Ethics Committee
Ethics committee address [1] 308924 0
Office of Research
Southern Adelaide Local health Network
Flinders Medical Centre
Flinders Drive
Bedford Park SA 5042
Ethics committee country [1] 308924 0
Australia
Date submitted for ethics approval [1] 308924 0
05/11/2019
Approval date [1] 308924 0
13/01/2020
Ethics approval number [1] 308924 0
273.19

Summary
Brief summary
The aim of this research is to establish how good current x-ray methods are at identifying artery wall dissections that are severe enough to require further treatment. Dissections are tears of the inner layer of the artery wall caused by angioplasty (the deliberate stretching open of a blocked or narrowed artery using a balloon placed inside the artery). Dissection is a common complication of treatment with most being minor and requiring no further action, however some dissections are severe enough that they need further treatment.
Currently very little is known about the accuracy of the current x-ray-based methods of identifying severe dissection. We also don’t know how much variation in diagnosis of dissection there is between doctors or whether there is a difference in the results of treatment at one year between mild and severe dissections.
In this research project we will be obtaining several other measurements in addition to x-rays (including conventional ultrasound imaging, intravascular ultrasound (a miniaturised form of ultrasound mounted on a catheter that is placed within the artery), and pressure measurments within the artery) to assess the severity of dissections seen after initial treatment. We will also follow up participants for one year after the treatment to check on the success of the treatment. If current x-ray methods are found to perform poorly, it may be possible to develop better methods using some of these other measurement methods.
We hope that this research will improve the diagnosis of dissection in the future and ensure that patients in the future will have better outcomes from their angioplasty treatment.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 112358 0
Dr Richard Allan
Address 112358 0
Department of Vascular and Endovascular Surgery
Flinders Medical Centre
Flinders Drive
Bedford Park SA 5042
Country 112358 0
Australia
Phone 112358 0
+61402395505
Fax 112358 0
+61882047106
Email 112358 0
richard.allan@sa.gov.au
Contact person for public queries
Name 112359 0
Dr Richard Allan
Address 112359 0
Department of Vascular and Endovascular Surgery
Flinders Medical Centre
Flinders Drive
Bedford Park SA 5042
Country 112359 0
Australia
Phone 112359 0
+61402395505
Fax 112359 0
+61882047106
Email 112359 0
richard.allan@sa.gov.au
Contact person for scientific queries
Name 112360 0
Dr Richard Allan
Address 112360 0
Department of Vascular and Endovascular Surgery
Flinders Medical Centre
Flinders Drive
Bedford Park SA 5042
Country 112360 0
Australia
Phone 112360 0
+61402395505
Fax 112360 0
+61882047106
Email 112360 0
richard.allan@sa.gov.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
We do not have approval to share IPD from our Ethics Committee
What supporting documents are/will be available?
No other documents available
Summary results
No Results