myocardial perfusion reserve
The ratio of maximal achievable myocardial blood flow during vasodilation to resting blood flow.
Full Definition
Myocardial perfusion reserve (MPR) represents the heart's ability to increase blood flow in response to increased metabolic demand or pharmacological vasodilation. It is calculated as the ratio of peak hyperemic flow to resting flow, with normal values typically above 2.5-3.0. MPR assessment can be performed using various imaging modalities including PET, MRI, and echocardiography with contrast agents. Reduced MPR may indicate epicardial coronary stenosis, microvascular dysfunction, or both. This parameter is particularly valuable for detecting balanced ischemia where wall motion abnormalities may not be apparent, and for assessing the functional significance of coronary lesions.
Usage
Usage note: Distinguish from coronary flow reserve, which is measured invasively in specific vessels.
In Context
- "PET imaging revealed reduced myocardial perfusion reserve in the LAD territory, suggesting hemodynamically significant stenosis." — Nuclear cardiology report
- "Global myocardial perfusion reserve was impaired despite absence of epicardial coronary disease, indicating microvascular dysfunction." — Research study findings