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The normal physiological blood flow is antegrade, flowing from the periphery towards the heart, so evidence of an opposite, retrograde flow might indicate a pathology. The presence of a reflux is likewise of note; a reflux, when not isolated in a vein (as simply retrograde), means that the blood flow is bi-directional where once the flow had ...
The instantaneous wave-free ratio (iFR, sometimes referred to as the instant wave-free ratio or instant flow reserve) is a diagnostic tool used to assess whether a stenosis is causing a limitation of blood flow in coronary arteries with subsequent ischemia. iFR is performed during cardiac catheterisation (angiography) using invasive coronary pressure wires which are placed in the coronary ...
In "antegrade" flow, the blood flows according to the normal flow within the circulatory system (e.g. veins flow towards the heart while arteries flows away from the heart). In "retrograde" flow, the flow would reverse (e.g. veins flow away from heart or arteries flow towards the heart). However, "retrograde" flow can be both abnormal or normal.
Flow-mediated dilation (FMD) refers to dilation (widening) of an artery when blood flow increases in that artery. [1] [2] The primary cause of FMD is release of nitric oxide by endothelial cells. [1] To determine FMD, brachial artery dilation following a transient period of forearm ischemia is measured using ultrasound. [3]
Fractional flow reserve (FFR) is a diagnostic technique used in coronary catheterization.FFR measures pressure differences across a coronary artery stenosis (narrowing, usually due to atherosclerosis) to determine the likelihood that the stenosis impedes oxygen delivery to the heart muscle (myocardial ischemia).
A Doppler ultrasound blood flow detector, commonly called Doppler wand or Doppler probe, and a sphygmomanometer (blood pressure cuff) are usually needed. The blood pressure cuff is inflated proximal to the artery in question. Measured by the Doppler wand, the inflation continues until the pulse in the artery ceases.
A vascular bypass is a surgical procedure performed to redirect blood flow from one area to another by reconnecting blood vessels. Often, this is done to bypass around a diseased artery, from an area of normal blood flow to another relatively normal area. It is commonly performed due to inadequate blood flow caused by atherosclerosis, as a part ...
White blood cells, carried to the area by the newly returning blood, release a host of inflammatory factors such as interleukins as well as free radicals in response to tissue damage. [2] The restored blood flow reintroduces oxygen within cells that damages cellular proteins, DNA, and the plasma membrane. Damage to the cell's membrane may in ...