flow-mediated dilation
Also written as: FMD — flow-mediated dilation
Non-invasive ultrasound technique measuring endothelial function by assessing arterial dilation response to increased flow stimulus.
Full Definition
Flow-mediated dilation (FMD) is a widely used non-invasive ultrasound-based technique for assessing endothelial function by measuring the arterial dilation response to increased shear stress. The test involves inducing forearm ischemia using a blood pressure cuff, followed by reperfusion that creates increased flow and shear stress in the brachial artery. High-resolution ultrasound measures the percentage increase in arterial diameter from baseline to peak dilation, typically occurring 45-60 seconds after cuff release. Normal FMD responses range from 5-15%, while blunted responses (<5%) indicate endothelial dysfunction. This technique provides valuable insight into nitric oxide-mediated endothelial function and serves as a surrogate marker for coronary endothelial health.
Usage
Usage note: Commonly abbreviated as FMD; ensure distinction from pharmacological dilation studies.
In Context
- "Flow-mediated dilation testing showed a blunted 3.2% response, indicating endothelial dysfunction." — Vascular laboratory report
- "The study protocol included flow-mediated dilation measurements at baseline and after six months of therapy." — Clinical trial methodology