A Prospective Study of Fractional Flow Reserve Assessment of Intermediate Coronary Stenoses in Severe Aortic Stenosis

Study Overview
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Brief Summary
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Coronary artery blockages can reduce blood flow to the heart muscle. Fractional flow reserve (iFR or FFR) assessment is an invasive tool used to determine how much blood flow is reduced. The investigators will perform iFR/FFR on all intermediate coronary stenoses using standard practice, immediately before (at the time of) transcatheter aortic valve replacement (TAVR) and after successful TAVR. The investigators will compare pre- and post-TAVR iFR/FFR values, and assess short-term outcomes. The investigators hypothesize that iFR/FFR values will be consistently and significantly higher pre-TAVR in comparison with post-TAVR for the same lesions.

Detailed Description
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The purpose of the study is to determine whether iFR assessment gives a valid assessment of coronary hemodynamics in patients with severe aortic stenosis. Several factors confound the interpretation of fractional flow reserve (FFR) in patients with severe aortic stenosis (AS) and intermediate severity coronary stenoses, and the widely accepted cut-off value of 0.80 may not be applicable to this patient population. Coronary flow reserve is known to be attenuated under conditions of left ventricular hypertrophy and severe AS, with one study showing improvement in coronary flow reserve after aortic valve replacement. Left ventricular hypertrophy produces fixed resistance secondary to external compression of the coronary microcirculation. This potentially results in failure to achieve maximal hyperemia with adenosine and can lead to false negative FFR results. Neurohormonal influences in aortic stenosis can further attenuate vasodilator response and potentially result in false negative FFR values. Both of these conditions result in the potential deferral of lesions which may have been hemodynamically significant in the absence of severe AS. At present, there are no studies which have demonstrated validity of FFR measurement in patients with severe AS. Here, the investigators propose a prospective study of iFR/FFR in patients with AS and indeterminate coronary lesions undergoing TAVR to understand the hemodynamic consequences of AS on iFR/FFR. The investigators hypothesize that iFR/FFR values will be consistently and significantly higher pre-TAVR in comparison with post-TAVR for the same lesions.

Official Title
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A Prospective Study of Fractional Flow Reserve Assessment of Intermediate Coronary Stenoses in Severe Aortic Stenosis

Conditions
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Coronary Artery Stenoses, Aortic Stenosis

Intervention / Treatment
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* Device: Volcano iFR/FFR Verrata Plus coronary pressure/flow wire


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All patients who have coronary stenoses between 40-70% severity and who have severe aortic stenosis undergoing TAVR work-up. Exclusion Criteria: Patients with documented intraprocedural hemodynamic instability, shock, or major adverse event (myocardial infarction, aortic rupture/dissection, stroke, left ventricular perforation, cardiac arrest). Contraindication to adenosine, presence of cardiogenic shock, presence of acute coronary syndrome.

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 110 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
Interventional Model Description: A single group of patients with severe aortic stenosis and intermediate coronary stenoses will undergo coronary physiology assessment with iFR/FFR before and after transcatheter aortic valve replacement.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: FFR/iFR arm<br>Volcano iFR/FFR Verrata Plus coronary pressure/flow wire | Device: Volcano iFR/FFR Verrata Plus coronary pressure/flow wire<br>* We will measure the degree of flow-limitation of intermediate severity coronary steonses using the iFR/FFR Verrata Plus coronary pressure/flow wire before and after transcatheter aortic valve replacement.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| FFR Values Prior to Transcatheter Aortic Valve Replacement | Hemodynamic significance of a coronary stenosis by measuring FFR immediately prior to TAVR | Immediately prior to transcatheter aortic valve replacement, during the index procedure | 
| FFR Values During the Transcatheter Aortic Valve Replacement (TAVR) | Hemodynamic significance of a coronary stenosis by measuring FFR immediately after TAVR | Immediately after transcatheter aortic valve replacement, during the index procedure | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Coronary Artery Stenoses, Aortic Stenosis