Go Beyond the Angiogram

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Overview

Physiology Indices
- Epicardial Assessment with FFR, RFR, and PPG
- IMR and CFR for Microvascular Assessment

Epicardial Assessment with FFR, RFR, and PPG

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Epicardial Assessment with FFR, RFR, and PPG

Epicardial physiology indices such as Fractional Flow Reserve (FFR), Resting Full-cycle Ratio (RFR) and Pullback Pressure Gradient (PPG) are utilized to determine the need and predict the likelihood of successful percutaneous coronary intervention.

FFR or RFR assessments are performed to assess the functional significance of epicardial coronary lesions at stress or rest, respectively.¹ PPG is a novel epicardial index that objectively quantifies focal epicardial disease to identify patients that are most likely to benefit from PCI.

Measure FFR, RFR and PPG with PressureWire™ X Guidewire, the world's only^2,3 wireless physiology wire with a hydrophilic-coated³ design for exceptional handling performance and accurate, reliable readings.^4,5

FFR: Fractional Flow Reserve
RFR: Resting Full-cycle Ratio
PPG: Pullback Pressure Gradient

FFR: Fractional Flow Reserve

Measuring FFR

FFR is a measure of blood pressure difference across a coronary artery stenosis to determine if a stenosis is physiologically significant, which can impede oxygen delivery to the heart muscle.¹

Why Use FFR?

34%

of the time angiography is inaccurate

Coronary angiography is not accurate in guiding the functional significance of stenosis in 34% of cases, compared to FFR.⁶

35%

risk reduction in death/MI with FFR

FFR-guided percutaneous coronary intervention (PCI) leads to a 35% risk reduction in death and myocardial infarction (MI), compared to relying only on angiography.⁷

62%

relative risk reduction in MACCE

Complete revascularization with PressureWire™ X Guidewire led to a 62% relative risk reduction in major adverse cardiac and cerebrovascular events (MACCE) at 1 year.⁸ The DANAMI-3-PRIMULTI trial also revealed that untreated “FFR-positive” non-infarct-related artery lesions are associated with a 31% incidence of MACCE at 1 year.⁸

RFR: Resting Full-Cycle Ratio

PressureWire™ X Guidewire measures RFR, a resting index that can be measured as an alternative to FFR depending on the clinical situation.⁹ Like FFR, RFR can identify functionally significant epicardial coronary stenosis. Unlike FFR, RFR is a non-hyperemic index that does not require the administration of a vasodilator such as adenosine.⁹

Measuring RFR

Clinically equivalent to the instantaneous wave-free ratio (iFR^‡) resting index, Abbott's RFR resting index scans through diastole and systole for the lowest pd/pa ratio. Unlike iFR^‡ or diastolic pressure ratio (dPR^‡), RFR is calculated from the lowest value of Pd/Pa over the entire cardiac cycle.¹⁰

Advantage of RFR

"The major advantage of RFR over iFR^‡ is that RFR does not require identification of a specific landmark or selection of a specific time point during diastole. By calculating the minimum Pd/Pa over the entire cardiac cycle, RFR calculates the maximum pressure gradient across the stenosis during resting status."
– Lee, et al. Circulation 2019

The cutoff value of RFR is 0.89:^9,11,12

When RFR ≤ 0.89, treatment with percutaneous coronary intervention (PCI) may be beneficial
When RFR > 0.89, deferral of PCI may be beneficial

Green indicates deferral of PCI may be beneficial, and red indicates a treatment of PCI may be beneficial.

Assessing Serial or Diffuse Lesions with RFR Pullback

In patients with multiple sequential stenoses or diffuse lesions, pullback pressure assessment can identify lesions with functional significance. RFR can be calculated along the entire length of a stenotic vessel using pullback, which measures pressure gradient at any given location.⁹

RFR Compared to Other Resting Indices

All resting pressure-derived indices closely correlate with one another, revealing the same discriminatory ability to guide intervention.¹⁰ The large IRIS-FFR retrospective study (1,506 patients, 1,833 lesions) examined deferred lesion failure among 5 resting indices—resting Pd/Pa, iFR^‡, RFR, dPR^‡, and DFR^‡—and concluded that all resting indices had similar outcomes in deferred lesions.¹²

Here are the cutoff values for the various non-hyperemic pressure ratios.¹⁴

Key RFR Findings

RFR has been studied in over 3,500 lesions and 2,500 patients, showing clinical accuracy and outcomes.

Objective Decision Making: Drift Matters

Drift is a phenomenon that affects the accuracy of most pressure measurement devices.¹⁷ Accuracy is particularly critical for resting ratios, as clinical decisions from resting ratios are more impacted by drift than FFR.^18,19

Compared to the hyperemic state, smaller separation between Pd and Pa at rest means even relatively small amounts of drift can lead to stenosis misclassification compared to FFR. That’s why it critical to detect even the slightest difference of pressure.

Use of FFR vs RFR¹⁴

Uses of FFR	RFR	FFR
Left Main Coronary Artery²⁰	–	+++
Systolic Dysfuntion²¹	–	+++
Post-PCI Side Branch Interrogation²²	–	+++
Post-PCI Assessment²³	–	+++
Equivalent Assessment
Multi-Vessel Disease²⁴	+++	+++
Diabetes²⁵	+++	+++
Uses of RFR
Tandem Lesions²⁶	+++	+
Diffuse Lesions²⁷	+++	+
Left Anterior Descending²⁸	+++	++
Acute Coronary Syndrome²⁹	+++	++

Chart courtesy of Ziad Ali, MD.

PPG: Pullback Pressure Gradient

PPG is a predictive tool that quantifies focal coronary disease to enable precise PCI decision-making for better patient outcomes.^30-34

Why Measure PPG?

Enhance Actionable Insights

PPG, a novel epicardial index, objectively quantifies focal epicardial disease to identify patients that are most likely to benefit from PCI^30,31
- PPG is a continuous metric; values approaching 1.0 represent focal CAD, whereas values close to 0 diffuse CAD³¹
EAPCI has recognized and endorsed the value of PPG in Pre-procedural PCI Planning to identify patterns of focal and diffuse disease³⁵

Maximize Patient Benefit

By measuring PPG, you can predict which patients are most likely to be angina-free post-PCI.^30,33

PPG demonstrated excellent predictive capacity for optimal revascularization
- PPG was significantly correlated with the change in post-PCI FFR³⁰

Predictive Capacity of PPG for FFR After PCI³⁰

Patients with high PPG (focal disease) reported greater improvement in angina and quality of life³³
- PPG changed the revascularization decision in 1 out of 7 patients³⁰
- Residual angina after PCI was ~2X more prevalent in patients with a low PPG (diffuse disease) than high PPG (focal)³³

Change in Angina Frequency From Baseline to 1-Year Follow-Up³⁴

Safe and Simple Workflow

The PPG Global Study demonstrated that PCI was safer to perform in patients with focal disease, resulting in lower rates of periprocedural MI.³⁴

PPG integrates seamlessly into FFR workflow and complements FFR insights as part of Abbott's Full Physiology solution.^3,30,36

Continue with a full physiology assessment with coronary flow reserve (CFR) and index of microcirculatory resistance (IMR)