Validation of Stenosis Assessment by Coronary Artery Computed Tomography Against Invasive Measurements of Fractional Flow Reserve in Patients With Significant Coronary Artery Stenoses

Study Overview
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Brief Summary
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This study will evaluate the effectiveness of CorCTA by comparing the results of the test with another imaging method called Fractional Flow Reserve (FFR), which is done as a part of the cardiac catheterization.

Detailed Description
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Invasive X-ray coronary angiography remains the reference standard for the evaluation of coronary artery stenoses. Recently, coronary artery computed tomography angiography (CorCTA) has been introduced as a non-invasive method for the evaluation of coronary artery stenoses and has been shown to be highly accurate in stenosis detection when compared to invasive X-ray angiography. While invasive X-ray angiography and CorCTA evaluate morphological features of coronary arterial plaques, fractional flow reserve is an invasive measure of the hemodynamic significance of a stenosis obtained in the catheterization laboratory by measuring changes in intracoronary arterial pressure before and after maximal vasodilation induced by intracoronary adenosine. An FFR value less than 0.75 has been shown to predict ischemia in vascular beds distal to the stenosis by radionuclide perfusion modalities and has been shown to be associated with worse outcomes. Therefore, FFR is considered to be an invasive hemodynamic reference standard for the evaluation of the hemodynamic significance of coronary arterial stenoses. While intravascular ultrasound (IVUS) can provide additional morphological information in intermediate stenoses, it can not provide further functional information and cannot be used in more significant stenoses as the IVUS probe cannot be advanced through stenotic lesions. We are currently conducting investigation in the validation of CorCTA against FFR in intermediate coronary artery stenoses (40-70%) (see below under Preliminary Data). However, CorCTA has not been validated against invasive hemodynamic measurements of fractional flow reserve in patients with stenoses >70% by invasive X-ray angiography. We hypothesize that CorCTA-derived measurements are accurate in the diagnosis of hemodynamically significant coronary artery stenoses, using FFR as the reference standard in patients with coronary artery stenoses>70%.

Conditions
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Coronary Artery Stenosis

Intervention / Treatment
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* Procedure: FFR, IVUS, VH, or combination of the three


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 21-85 Presence of at least one obstructive coronary artery stenosis as defined by: Previous catheterization or CT angiogram with any lesion 70% or greater Previous positive functional stress test (this does not include CTA alone) Ability and Willingness to provide informed consent Ability and Willingness to perform required follow up procedures Exclusion Criteria: History of coronary artery bypass graft surgery Previously revascularized lesion Creatinine>1.6 mg/dL or GFR<30 pre-procedure per institutional standards Known Pregnancy Inability to perform CTA Arrhythmia precluding diagnostic CT examination Contrast agent allergy that cannot be adequately premedicated Severe PVD precluding cardiac catheterization Patient not a candidate for IVUS and FFR Inability or unwillingness to provide informed consent Inability or unwillingness to perform required follow up procedures

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 85 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: CorCTA<br>Fractional Flow Reserve (FFR), Intravascular Ultrasound (IVUS), Virtual Histology (VH) or some combination of these three procedures | Procedure: FFR, IVUS, VH, or combination of the three<br>* Fractional Flow Reserve (FFR), Intravascular Ultrasound (IVUS), Virtual Histology (VH) or some combination of these three procedures will be completed during the cardiac catheterization procedure.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The CT-derived endpoints: Study lesion %DS predicting FFR<0.75; %AS predicting FFR<0.75; MLD predicting FFR<0.75; Study lesion MLA predicting FFR<0.75; IVUS-derived endpoints: Study lesion MLD predicting FFR<0.75; MLA predicting FFR<0.75 |  | Upon completion of tests | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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coronary artery stenoses