coronary flow reserve
The ratio of maximum coronary blood flow during stress to resting flow, indicating coronary microvascular function.
Full Definition
Coronary flow reserve (CFR) represents the ability of the coronary circulation to increase blood flow above resting levels in response to maximal vasodilatory stimuli. CFR is calculated as the ratio of peak hyperemic flow velocity to baseline flow velocity, typically measured using Doppler echocardiography, PET, or invasive techniques. Normal CFR values are generally >2.5, with reduced values (<2.0) indicating impaired coronary microvascular function or epicardial stenosis. CFR assessment is valuable in detecting microvascular disease, assessing the functional significance of intermediate coronary stenoses, and monitoring treatment response. Factors that can reduce CFR include diabetes, hypertension, left ventricular hypertrophy, and infiltrative cardiomyopathies, even in the absence of epicardial coronary disease.
Usage
Usage note: Distinguish from fractional flow reserve (FFR), which measures pressure ratios rather than flow ratios.
In Context
- "Coronary flow reserve was reduced at 1.8, suggesting microvascular dysfunction." — PET perfusion report
- "Normal coronary flow reserve of 3.2 was documented in the left anterior descending artery territory." — Stress echocardiography report