Go Beyond the Angiogram

With a Comprehensive Physiology Assessment

Overview

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

FFR and RFR for Epicardial Assessment

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FFR and RFR for Epicardial Assessment

To determine the need for percutaneous coronary intervention, physiology indices such as fractional flow reserve (FFR) and resting full-cycle ratio (RFR) are used to identify functionally significant epicardial coronary stenoses at stress or rest.¹

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

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

Abbott's PressureWire™ X Guidewire measures resting full-cycle ratio (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 may be beneficial and red indicates a treatment of PCI.

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 Non-Hyperemic Pressure Ratio (RFR)?¹⁴

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

Chart courtesy of Ziad Ali, MD.

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

Comprehensive Physiology Workflow

The PressureWire™ X Guidewire and CoroFlow^‡ Cardiovascular System can provide a comprehensive physiology assessment to measure FFR, RFR, IMR and CFR.

Learn More About the Physiology Workflow

References

Pijls, NH., et al. Measurement of fractional flow reserve to assess the functional severity of coronary-artery stenoses. N Engl J Med. 1996;334(26):1703-1708.
Volcano Corp. Verrata^‡ guidewire and PrimeWire Prestige^‡ Plus guidewire IFUs, Opsens Inc. OptoWire^‡ guidewire and OptoWire^‡ II guidewire IFUs, ACIST Medical Systems. Navvus^‡ Microcatheter IFU, Boston Scientific Corporation. Comet^‡ guidewire IFU.
PressureWire™ X Guidewire Instructions for Use (IFU). Refer to IFU for additional information.
Pijls, NH., et al. Fractional Flow Reserve Versus Angiography for Guiding Percutaneous Coronary Intervention in Patients with Multivessel Coronary Artery Disease. 2-Year Follow-Up of the FAME Study. JACC. 2010; 56(3): 177-184.
Fearon, WF., et al. Fractional Flow Reserve-Guided PCI as Compared with Coronary Bypass Surgery. N Engl J Med, Nov 4, 2021.
Corcoran, D., et al. Fractional flow reserve: a clinical perspective. Int J Cardiovasc Imaging. 2017;33(7):961‐974.
Pijls, NH., et al. Fractional flow reserve versus angiography for guiding percutaneous coronary intervention in patients with multivessel coronary artery disease: 2-year follow-up of the FAME (Fractional Flow Reserve Versus Angiography for Multivessel Evaluation) study. J Am Coll Cardiol. 2010;56(3):177‐184.
Smits, PC., et al. Fractional flow reserve–guided multivessel angioplasty in myocardial infarction. N Engl J Med. 2017; 376:1234-1244.
Svanerud, J., et al. Validation of a novel non-hyperaemic index of coronary artery stenosis severity: the Resting Full-cycle Ratio (VALIDATE RFR) study. EuroIntervention. 2018;14:806-814.
Lee, JM., et al. Physiological and clinical assessment of resting physiological indexes. Circulation. 2019;139:889-900.
Jeremias, A., et al. Resting full-cycle ratio (RFR): a novel physiologic index compared to Fractional Flow Reserve (FFR) in assessing the hemodynamic severity of a coronary stenosis: ILUMIEN I + PREDICT. EuroPCR 2018.
Ahn, JM., et al. IRIS FFR: prognostic performance of five resting pressure-derived indexes of coronary physiology. TCT 2018.
Nam, CW., et al. Fractional ﬂow reserve assessment of serial lesions. Radcliffe Cardiology. April 2014.
Ali, Z., Invasive Assessment of Coronary Physiology Is Here to Stay! TCT 2019.
Kumar, G., et al. RE-VALIDATE: REal world VALIDATion of the non-hyperemic InDex of coronary Artery sTEnosis severity: resting full-cycle ratio (RFR) – RE-VALIDATE RFR. CRT 2019.
Lee, JM., et al. Clinical Outcome of Lesions with discordant results among different invasive physiologic indices. Circulation Journal 2019 83:2210-2221.
Jeremias, A., et al. A Test in Context: FFR: Accuracy, Prognostic Implications, and Limitations. J AM Coll Cardiol. 2017; 69:2748-58.
Veer, M, et al. Comparison of Different Diastolic Resting Indexes to iFR. J AM Coll Cardiol. 2017;70(25):3088-3096.
Cook, C. Quantification of the Effect of Pressure Wire Drift on the Diagnostic Performance of FFR, iFR, & Pd/Pa. Circ Cardiovasc Interv. 2016;9(4):e002988.
Mallidi, J., et al. Long-term outcomes following fractional flow reserve-guided treatment of angiographically ambiguous left main coronary artery disease: a meta-analysis of prospective cohort studies. Catheter Cardiovasc Interv. 2015;86(1):12-18.
Johnson, NP., et al. Diastolic pressure ratio: new approach and validation vs the instantaneous wave-free ratio. Eur Heart J. 2019; 40(31):2585-2594
Koo, BK., et al. Physiologic assessment of jailed side branch lesions using fractional flow reserve. J Am Coll Cardiol. 2005;46(4):633-637.
Johnson, NP., et al. Prognostic value of fractional flow reserve: linking physiologic severity to clinical outcomes. J Am Coll Cardiol. 2014;64(16):1641-1654.
Escaned, J., et al. Clinical outcomes of state-of-the-art percutaneous coronary revascularization in patients with de novo three vessel disease: 1-year results of the SYNTAX II study. Eur Heart J. 2017;38(42):3124-3134.
DEFINE-FLAIR Trial Investigators. Comparison of major adverse cardiac events between instantaneous wave-free ratio and fractional flow reserve–guided strategy in patients with or without type 2 diabetes. JAMA Cardiol. 2019;4(9):857-864.
Nijjer, SS., et al. Pre-angioplasty instantaneous wave-free ratio pullback provides virtual intervention and predicts hemodynamic outcome for serial lesions and diffuse coronary artery disease. JACC Cardiovasc Interv. 2014;7(12):1386-96.
Jeremias, A., et al. Blinded physiological assessment of residual ischemia after successful angiographic percutaneous coronary intervention: the DEFINE PCI study. JACC Cardiovasc Interv. 2019;12(20):1991-2001.
Sen, S., et al. Clinical eventsa after deferral of LAD revascularization following physiological coronary assessment. J Am Coll Cardiol. 2019;73(4):444-453.
Escaned, J., et al. Safety of the deferral of coronary revascularization on the basis of instantaneous wave-free ratio and fractional flow reserve measurements in stable coronary artery disease and acute coronary syndromes. JACC Cardiovasc Interv. 2018;11(15):1437-1449.

MAT–2302508 v1.0

Important Safety Information

Coroventis^‡ CoroFlow^‡ Cardiovascular System

Indications: CoroFlow^‡ is indicated to provide hemodynamic information for use in the diagnosis of patients with cardiovascular diseases.

CoroFlow^‡ is intended for use in catheterization and related cardiovascular specialty laboratories to compute and display various physiological parameters based on the output from one or more measuring devices.

Contraindications: The system has no patient alarm functions. Do not use for cardiac/vital signs monitoring.

Warnings:

If CoroFlow^‡ is used together with 3rd party infusion catheters for assessment of Absolute Flow and Resistance, ensure that the maximum infusion rate per manufacturers instruction is not exceeded or vessel injury may occur.
Do not use the CoroFlow^‡ measurement system if there is reason to believe the system's security has been compromised or if the system was unaccounted for a period of time (i.e. misappropriated, modified or tampered with).
Do not leave the CoroFlow^‡ measurement system unattended when logged in as a PC Administrator
To protect the privacy and security of sensitive information, including electronic protected health information (EPHI), and to protect the integrity of the system itself, the system should be located in a physically secure, access-controlled environment.
To protect the privacy and security of sensitive information, including electronic protected health information (EPHI), the PC on to which CoroFlow^‡ is installed must be configured according to the Installation Instructions in this manual. Failure to configure the PC correctly may result in increased risk for unauthorized release of protected health information. Windows settings include:
- Activation and configuration of restricted user Access
- Activation of Windows Firewall and blocking of network connections
- Activation of Windows Bitlocker drive encryption
- Activation of Windows Secure Boot
- Activation of Windows Anti-Virus scanning
- Activation of Windows update
Use of this equipment adjacent to or stacked with other equipment should be avoided because it could result in improper operation. If such use is necessary, this equipment and the other equipment should be observed to verify that they are operating normally.
Use of accessories, transducers and cables other than those specified or provided by Coroventis^‡ could result in increased electromagnetic emissions or decreased electromagnetic immunity of this equipment and result in improper operation.
Portable RF communications equipment (including peripherals such as antenna cables and external antennas) should be used no closer than 30 cm (12 inches) to any part of CoroFlow^‡, including cables specified by Coroventis^‡. Otherwise, degradation of the performance of this equipment could result.

Precautions:

The PC and CoroHub^‡ shall not be placed within the patient environment (1.5 m from patient).
For operation of other devices used in conjunction with CoroFlow^‡ consult the IFU for each of these devices for details on indication, handling and safety information.
It is recommended to ensure local routines for data backup of stored recordings. CoroFlow^‡ does not create backup of stored data.
Always check minimum performance requirement on PC to ensure compatibility with CoroFlow^‡.
It is recommended to install CoroFlow^‡ on a PC with backup battery to avoid interruption in case of power failure.
Always manually review and confirm valid cursor positions and detected heart beats.
Ensure that Pa and Pd pressure waveforms are aligned in phase and offset after equalization, or indices can be mis-calculated.
Confirm that the correct Wi-Box is selected by manually matching the Wi-Box ID number with the Wi-Box in the lab.
Changing parameter settings outside of default values may affect measurement performance, only for research purposes.
Only to be used by healthcare professionals
Using a network location to store data may cause previously unidentified risks if the network malfunctions
The assembly of medical electrical systems and modifications during the actual service life require evaluation to the requirements according to IEC 60601-1 standard series.
CoroHub^‡ does not have any serviceable parts and require no field maintenance. No modification or tampering with CoroHub^‡ is permitted.
CoroHub^‡ shall not be immersed in liquid.
CoroHub^‡ shall not be used if it has been subject to damage
Direct connection to a non-secure network, like the internet, may interfere with correct operation and/or result in inappropriate access to patient information. Furthermore, it should be noted that reconfiguring a used network may lead to inability to import patient as well as export examination data, ultimately leading to a risk of loss of patient and examination data. To avoid this problem Coroventis^‡ recommends verifying network settings in the system setup after each change.

MAT-2007904 v3.0

PressureWire™ X Guidewire

Indications: The PressureWire™ X Guidewire is indicated to direct a catheter through a blood vessel and to measure physiological parameters in the heart and in the coronary and peripheral blood vessels. Physiological parameters include blood pressure. The PressureWire™ X Guidewire can also measure blood temperature.

Contraindications: This guidewire is contraindicated for use in the cerebral vasculature.

Warnings:

No modification of this device is allowed.
The PressureWire™ X Guidewire is supplied sterile. Discard the guidewire if the pouch is opened or damaged, compromising the sterile barrier. The guidewire is designed for single use only and shall not be reused or resterilized. Adverse effects of using a non-sterile or resterilized guidewire may include, but are not limited to:
- Local and/or systemic infection
- Mechanical damage
- Inaccurate readings
Observe all guidewire movements. Whenever the guidewire is moved or torqued, the tip movement should be examined under fluoroscopy. Never push, withdraw, or torque the guidewire if it meets resistance or without observing corresponding movement of the tip, otherwise vessel/ventricle trauma may occur.
Torquing or excessive manipulation of the guidewire in a sharp bend, against resistance, or repeated attempts to cross a total vessel occlusion may:
- Cause dissection or perforation of blood vessels
- Cause vessel spasm
- Damage and/or fracture the guidewire
When introducing the guidewire, flush the catheter and administer anticoagulation as for a standard catheterization procedure or clotting may occur.
Do not use the guidewire in the ventricles if the patient has a prosthetic mechanical or biological valve. It may result in damage to both the prosthesis and the guidewire, which may cause injury or death.
Use of the PressureWire™ X Guidewire in conjunction with interventional devices with a short rapid exchange may result in a folded or fractured guidewire.
High frequency surgical devices must not be used on a patient at the same time as the guidewire.

Precautions:

The PressureWire™ X Guidewire is a delicate instrument and should be handled carefully.
Make sure that the transmitter is kept dry to ensure accurate pressure and/or temperature readings. Inaccurate readings may necessitate device replacement.
Do not use the guidewire in conjunction with atherectomy catheters. It may damage the guidewire.
Do not withdraw or manipulate the guidewire in a sharp-edged object. It may result in abrasion of the guidewire coating.
Factors that may affect the accuracy of the diagnostic information include, but are not limited to:
- Improper placement of the aortic pressure sensor.
- Failure to achieve maximum coronary and myocardial hyperemia in FFR procedures.
- Blood flow affected by the position of interventional devices, such as balloon catheters.
Guidewire readings may be affected by defibrillation. Rezero the guidewire after defibrillation use.
Do not measure pressure when the guidewire sensor element is in a sharp bend or in contact with atrial or ventricular walls. It might result in pressure artifacts.
Do not use the PressureWire™ X Guidewire together with another guidewire, for so called jailed wire technique, due to difficulty in guidewire withdrawal and possible guidewire entrapment.
Store at room temperature (15°C – 25°C) in a dry and dark place.

Potential Adverse Events: Potential complications which may be encountered during all catheterization procedures include, but are not limited to: vessel dissection or occlusion, perforation, embolus, spasm, local and/or systemic infection, pneumothorax, congestive heart failure, myocardial infarction, hypotension, chest pain, renal insufficiency, serious arrhythmias, or death.

In addition, this device has a coating containing Polyethylene Glycol (PEG); potential allergic reactions (anaphylaxis) may occur during the interventional procedure if the patient is allergic to PEG.

MAT-2103599 v2.0

CARDIOVASCULAR

Go Beyond the Angiogram

With a Comprehensive Physiology Assessment