Pullback Pressure Gradient (PPG) Global Registry

Study Overview
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Brief Summary
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The purpose of this study is to determine the predictive capacity of the Pullback Pressure Gradient (PPG) index for post-PCI FFR and to determine the impact of the PPG index on clinical decision making about revascularization and on clinical outcomes.

Detailed Description
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A Fractional Flow Reserve (FFR) evaluation comprises measurement of a distal single value and a pullback maneuver during hyperemic conditions. The PPGindex is a novel metric derived from the FFR pullback curve.3 This metric complements the distal FFR value by informing the spatial distribution of epicardial resistance (i.e. focal or diffuse) along the coronary vessel. The PPGindex relies on two components: first, the magnitude of pressure drop determined as a maximal pressure gradient over 20 millimeters relative to the total vessel gradient; and second, the length of functional disease relative to total vessel length. These two parameters are weighted equally to provide a metric that ranges from 0 to 1. PPGindex values approaching 1 represent functional focal coronary artery disease (CAD) whereas values close to 0 represent diffuse functional CAD. Until now, the interpretation of the FFR pullback relied on visual assessment. The PPGindex quantifies the pattern of functional CAD and has been shown to predict functionally complete revascularization. Percutaneous revascularization in vessels with high PPGindex is associated with high post-PCI FFR and vast improvement in epicardial conductance whilst PCI in vessels with low PPGindex results in low post-PCI FFR. An curvilinear relationship is observed between PPGindex and functional gain (i.e. FFR post-PCI minus FFR pre-PCI). The PPGindex, therefore, aims to predict the response to PCI in physiological terms. Calculation of the PPGindex is indicated in cases with an FFR≤0.80. FFR pullbacks are performed under hyperemic conditions at a steady pace during manual pullback. A calculation of the PPGindex using the Coroflow console (Coroventis Research Ab, Uppsala, Sweden) is available for online use and computes the PPG value immediately after the pullback maneuver. This software also includes an automated drift correction. The pullback curve is depicted on an dedicated pullback display screen and the pressure gradients are shown per millimeter, allowing correlation between the location of pressure step-ups and the anatomical target for PCI. In summary, we can distinguish three points where FFR influences the clinical decision-making process. First, an FFR ≤0.80 indicates potential benefit of revascularization. Second, the pullback curve assesses disease pattern and PPG index value quantifies it, helping de physician in the decision about treatment options (e.g. PCI, CABG or OMT). And, third, the location of pressure step-ups along the vessels helps plan the PCI strategy with respect to coverage of functional disease. A combined FFR and PPG-guided PCI strategy has the potential to improve patient selection and enhance procedural planning. The purpose of this study is to determine the predictive capacity of the PPG index for post-PCI FFR and to determine the impact of the PPG index on clinical decision making about revascularization and on clinical outcomes.

Official Title
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Pullback Pressure Gradient (PPG) Global Registry: Prospective Evaluation of the Impact of the PPG Index on Clinical Decision Making and Outcomes

Conditions
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Chronic Coronary Insufficiency, Non ST Elevation Myocardial Infarction

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Consecutive patients with stable coronary artery disease or stabilized acute coronary syndrome and invasive FFR measurement ≤0.80. Exclusion Criteria: Angiographic exclusion criteria Ostial lesions. Severe vessel tortuosity. Vessel rewiring deemed 'difficult' by the operator. Bifurcation with planned two-stent strategy. NSTEMI culprit vessel. STEMI Uncontrolled or recurrent ventricular tachycardia. Hemodynamic instability Severe renal dysfunction, defined as an eGFR <30 mL/min/1.73 m2

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 100 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Stable CAD or stabilized NSTEMI (ACS) with significant epicardial lesions defined as FFR≤0.80.<br>The PPG Global Registry an investigator-initiated, observational, multicenter study of patients with an indication for PCI based on coronary angiography and FFR ≤0.80. After confirmation of intention to treat with PCI, a manual pullback with PPG analysis will be performed. A second level of decision making is then performed concerning PCI, coronary artery bypass grafting (CABG) or medical therapy (OMT). Patients will undergo PCI at operator discretion and post-PCI FFR will be measured. Clinical follow-up will be performed at 1, 2 and 3 years. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Predictive capacity of the PPG index for post-PCI FFR. | Describe the relationship between pre PCI PPG and post-PCI FFR | 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To assess the relationship between baseline PPG index and major adverse cardiovascular events (cardiac death, peri-procedural and spontaneous myocardial infarction and target vessel revascularization) at one, two and three years. | Assess whether the PPG and identification of CAD endo-type has a relationship with per and post-procedure events | 3 years after completion of inclusion | 
| Difference between baseline and 12 month follow-up in the Seattle Angina Questionnaire (SAQ) stratified by PPG index. | Assess the relationship with symptoms assessed by the SAQ and PPG and persistent/recurrent angina post-PCI | 1 years after completion of inclusion | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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FFR, PPG, PCI