Coronary physiology testing refers to a group of diagnostic tests that assess the functional significance of coronary artery disease (CAD) by evaluating blood flow and pressure within the coronary arteries. These tests provide valuable information about the severity of blockages or narrowings in the arteries and help guide treatment decisions for individuals with CAD.
Some common coronary physiology tests include:
Fractional Flow Reserve (FFR): FFR is a technique used during coronary angiography to measure the pressure difference across a blockage in a coronary artery. It helps determine if the blockage is causing a significant reduction in blood flow to the heart muscle and if intervention (such as angioplasty and stenting) is warranted. FFR values less than 0.80 typically indicate significant narrowing and reduced blood flow.
Instantaneous Wave-Free Ratio (iFR): iFR is a newer technique similar to FFR that also measures the pressure difference across a blockage in a coronary artery but does so during a specific part of the cardiac cycle known as the wave-free period. iFR can provide similar diagnostic information to FFR but may be easier to perform and less dependent on the use of adenosine, a medication used to induce hyperemia during FFR.
Coronary Flow Reserve (CFR): CFR is a measure of the ability of the coronary arteries to increase blood flow in response to increased demand, such as during exercise or medication-induced stress. It is typically assessed using Doppler ultrasound or other imaging techniques and provides information about the overall health and function of the coronary arteries.
Index of Microcirculatory Resistance (IMR): IMR is a measure of microvascular function that assesses resistance to blood flow in the small blood vessels of the heart. It provides information about the health of the microcirculation and can help identify individuals at risk of adverse outcomes, such as heart attack or heart failure.
These coronary physiology tests play a crucial role in the management of CAD by providing additional information beyond traditional angiography about the functional significance of coronary artery narrowings