The diseases have been categorized as patches (cause dead spots or patches in the lawn), rings (cause rings of dead or affected grass), or leaf blight (affect individual blades of grass, often over a wide area and no distinct patch or ring pattern may be noticeable).
PVR, abbreviation for pulmonary vascular resistance. To measure changes in blood vessel size or changes in gas volume in the lungs to assist in diagnosing diseases such as deep vein thrombosis (DVT), chronic obstructive pulmonary disease (COPD), and some peripheral vascular disorders. Veins, arteries, and lungs. None.
FloWireÂ® Doppler Guide Wire image, courtesy Volcano Corporation. What is FFR? Fractional Flow Reserve, or FFR, is a guide wire-based procedure that can accurately measure blood pressure and flow through a specific part of the coronary artery. FFR is done through a standard diagnostic catheter at the time of a coronary angiogram (a.k.a. cardiac catheterization). The measurement of Fractional Flow Reserve has been shown useful in assessing whether or not to perform angioplasty or stenting on intermediate blockages. 1  The point of opening up narrowings or blockages in the coronary arteries is to increase blood flow to the heart.