Resting Full-cycle Flow Ratio (RFR) Versus Angiography to Guide Revascularization Strategy in Patients Undergoing Coronary Artery By-pass Grafting (CABG)

Study Overview
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Brief Summary
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Different trials have shown that fractional flow reserve (FFR) could successfully guide revascularization in patients undergoing percutaneous coronary intervention (PCI). It is conceivable that a similar revascularization guidance could be useful also for surgical revascularization i.e. coronary by-pass graft (CABG). Experience learns that grafts placed on vessels with hemodynamically non-significant stenosis often occlude due to competitive antegrade flow. Resting full-cycle Flow Ratio (RFR) is a measurement performed to evaluate the hemodynamic severity of coronary stenosis. Differently from FFR which is a measurement performed in maximal hyperemia, the RFR is a measurement that is performed in rest and therefore may predict better than FFR the baseline equilibriums that could lead to graft failure, while it has similar capacity to identify hemodynamically significant stenosis as FFR. It is unknown whether RFR guided CABG revascularization is superior as compared to angiography alone.

Official Title
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Resting Full-cycle Flow Ratio (RFR) Versus Angiography to Guide Revascularization Strategy in Patients Undergoing Coronary Artery By-pass Grafting (CABG): RFR-CABG Trial

Conditions
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Coronary Artery Disease

Intervention / Treatment
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* Procedure: RFR guided CABG
* Procedure: Angio guided CABG


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All patients between 18 or older undergoing CABG Patients willing and capable to provide written informed consent Exclusion Criteria: Previous CABG Concomitant severe valvular disease intervention Remaining (expected) coronary stenosis of > 50% diameter stenosis distally to graft anastomosis Left ventricular ejection fraction <30% Known transmural myocardial infarction Documented microvascular disease RFR/FFR measurement judged impossible Life expectancy <2 years Participation in other investigational clinical trials

Ages Eligible for Study
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Minimum Age: 18 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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: International prospective randomized multicenter superiority trial
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: angiography guided CABG<br>angiography guided CABG | Procedure: Angio guided CABG<br>* All patients will undergo RFR and FFR measurement before CABG. RFR and FFR values will be blinded to the patients. In the control arm the RFR values will be blinded to the cardiothoracic surgeon.<br>|
| Experimental: RFR guided CABG<br>RFR guided CABG | Procedure: RFR guided CABG<br>* All patients will undergo RFR and FFR measurement before CABG. RFR and FFR values will be blinded to the patients. In the experimental arm the decision to revascularize will be based on RFR.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of participants who deceased, had a Myocardial Infarction (MI), Clinically-Driven Target Vessel Revascularization (CD-TVR), Stroke or Graft Dysfunction at 3 months post CABG |  | 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cut-off value for the RFR that best predicts graft occlusion |  | Baseline | 
| Number of participants with graft dysfunction at 3 months post CABG |  | 3 months | 
| Major adverse cardiac or cerebrovascular event (MACCE), a composite of Death, MI, CD-TVR and Stroke at 1 year |  | 1 year | 
| Major adverse cardiac or cerebrovascular event (MACCE), a composite of Death, MI, CD-TVR and Stroke at 3 years |  | 3 years | 
| CD-TVR at 3 months post CABG |  | 1 year | 
| CD-TVR at 1 year post CABG |  | 1 year | 
| CD-TVR at 3 years post CABG |  | 3 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Graft dysfunction, RFR guided CABG, angiography guided CABG