Go Beyond the Angiogram

With a Comprehensive Physiology Assessment

Overview

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

IMR and CFR for Microvascular Assessment

Index of Microcirculatory Resistance (IMR) and Coronary Flow Reserve (CFR) for Microvascular Assessment

Among stable patients undergoing cardiac catheterization, the majority (59%) have little or no angiographic abnormality, as shown in the visual¹ in spite of the fact that the majority have symptoms of a coronary disorder.² Patients with ischemia and no obstructive artery disease (INOCA) may have coronary microvascular dysfunction (CMD). As a group, these patients are underdiagnosed.

The index of microcirculatory resistance (IMR) and coronary flow reserve (CFR) are used to assess the microvasculature to help provide a diagnosis of CMD.

Estimated Prevalence of INOCA and CMD³

IMR and CFR are calculated from the two temperature sensors located in proximal and distal positions on the PressureWire™ X Guidewire.^4,5These sensors allow physicians to capture the measurements using thermodilution.

Using Thermodilution to Evaluate IMR and CFR⁶

When an interventional cardiologist (IC) injects saline flush at ambient temperature into the artery, the PressureWire™ X Guidewire detects temperature changes as the saline passes the proximal and distal sensors.

Coronary flow is estimated based on the time it takes the saline to pass between proximal and distal sensors. This time (in seconds) is known as the Mean Transit Time (Tmn).

Learn How to Assess and Diagnose CMD by Following the CATH CMD Algorithm

Learn More

The CoroFlow^‡ Cardiovascular System can be used to review physiology measurements.⁷

IMR = measures the blood flow in microvasculature

CFR = measures the blood flow in the epicardial arteries and the microvasculature

Diagnosing Coronary Microvascular Dysfunction

IMR and CFR cutoffs in a population of INOCA patients are shown on the right (based on CorMicA trial).⁸

IMR and CFR Cutoffs for Coronary Microvascular Dysfunction Diagnosis

Green indicates normal values, red indicates abnormal values

Cutoff values are specific for INOCA patients

Why Assess for Coronary Microvascular Dysfunction?

INOCA patients may be suffering from persistent angina due to CMD and are at higher risk of major adverse cardiac events (MACE).⁹ Until such symptomatic patients receive proper treatment, they are frequent consumers of healthcare resources due to repeat evaluations, cath lab tests, emergency room visits, and hospitalizations.^10-12

As the CorMicA study reveals, patients may benefit when coronary microvascular dysfunction is accurately diagnosed and properly treated.^8,13

27% Improvement in Angina Severity^†

18% Improvement in Quality of Life

Coronary Microvascular Dysfunction Diagnosis Improves Outcomes

Proper assessment, diagnosis, and treatment of CMD can improve outcomes in CMD patients at high risk for MACE and reduce healthcare burden.^3,9,14

^† According to the Seattle Angina Questionnaire score.

Following Society Guidelines for IMR and CFR

ACC/AHA guidelines recommend measuring IMR and CFR using a guidewire-based approach for symptomatic patients who exhibit no significant evidence of epicardial stenosis.

The AHA/ACC Clinical Practice Guideline on chest pain includes Class IIa recommendation for guidewire-based assessment for INOCA patients.¹⁶

Recommendations for Patients With INOCA	Class^a	Level^b
For patients with persistent stable chest pain and non-obstructive CAD and at least mild myocardial ischemia on imaging, it is reasonable to consider invasive coronary function testing to improve the diagnosis of coronary microvascular dysfunction and to enhance risk stratification.	IIa	B-NR

CFR = coronary flow reserve; CMR = cardiac magnetic resonance; ECG = electrocardiogram;
FFR = fractional flow reserve; iwFR = instantaneous wave-free ratio; LAD = left anterior descending; PET = positron emission tomography.

a Class of recommendation.

b Level of evidence.

Level-NR: Level (Quality) of Evidence Level B-NR (non-randomized): moderate-quality evidence from 1 or more well designed, well executed non-randomized studies, observational studies or registry studies. RCTs. Meta-analyses of such studies.

The PressureWire™ X Guidewire with CoroFlow^‡ Cardiovascular System has the capability to wirelessly measure comprehensive physiology indices to assess for epicardial disease (FFR, RFR) and microvascular dysfunction (IMR, CFR).^4,7

Learn more about Coronary Microvascular Dysfunction (CMD)

References

Patel, MR., et al. Low diagnostic yield of elective coronary angiography. N Engl J Med. 2010;362:886-895. doi:10.1056/NEJMoa0907272.
Ford, TJ., et al. How to diagnose and manage angina without obstructive coronary artery disease: lessons from the British Heart Foundation CorMicA Trial. Interv Cardiol Rev. 2019;14(2):76-82.
Kunadian V, et al. EAPCI Expert Consensus Document. Eur Heart J 2020;0:1-21.
PressureWire™ Guidewire Instructions for Use (IFU). Refer to IFU for additional information.
Fearon and Kobayashi, Invasive assessment of the coronary microvasculature, CCI 2017; 10:e005361.
DeBruyne, et al. Coronary Thermodilution to Assess Flow Reserve Experimental Validation. Circulation. 2001;104:2003-2006.
CoroFlow^‡ Cardiovascular System Instructions for Use (IFU). Refer to IFU for additional information.
Ford, TJ., et al. 1-year outcomes of angina management guided by invasive coronary function testing (CorMicA). J Am Coll Cardiol Intv. 2020;13:33-45.
Taqueti, VR., et al. Coronary microvascular disease pathogenic mechanisms and therapeutic options: JACC state-of-the-art review. J Am Coll Cardiol. 2018;72:2625–2641. doi:10.1016/j.jacc.2018.09.042.
Rahman, H., et al. Diagnosis of patients with angina and non-obstructive coronary disease in the catheter laboratory. Heart. 2019;105:1536-1542.
Lee, B., et al. Invasive evaluation of patients with angina in the absence of obstructive coronary artery disease. Circulation. 2015;131:1054–1060.
Reriani, M., et al. Coronary endothelial function testing may improve long-term quality of life in subjects with microvascular coronary endothelial dysfunction. Open Heart. 2019;6:e000870. doi: 10.1136/openhrt-2018-000870.
Ford, TJ., et al. Stratified medical therapy using invasive coronary function testing in angina: the CorMicA trial. J Am Coll Cardiol. 2018;72:2841-2855.
Jespersen, L., et al. Stable angina pectoris with no obstructive coronary artery disease is associated with increased risks of major adverse cardiovascular events. Eur Heart J. 2012;33:734-744. doi:10.1093/eurheartj/ehr331.
Knuuti, J., et al. 2019 ESC Guidelines for the diagnosis and management of chronic coronary syndromes. European Heart Journal 2019.
Gulati, M., et al. 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines.

MAT-2302509 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 v2.0

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