Pulmonary vascular resistance measures how much the blood vessels in the lungs resist blood flow — a key number in diagnosing and classifying pulmonary hypertension.
Result in Wood units; multiply by 80 for dyn·s·cm⁻⁵.
Normal pulmonary vascular resistance.
Mildly elevated.
Part of the precapillary pulmonary hypertension definition.
Markedly elevated.
Given: MPAP 25, PCWP 10 mmHg, cardiac output 5 L/min.
Narrowed or stiffened pulmonary vessels raise the resistance to flow.
Subtracting wedge pressure (a surrogate for left atrial pressure) isolates resistance in the pulmonary vessels themselves, rather than pressure elevation caused by left heart disease.
Less than 2 Wood units (under 240 dyn·s·cm⁻⁵). A PVR above 3 Wood units is part of the modern definition of precapillary pulmonary hypertension.
Multiply Wood units by 80. So 3 Wood units equals 240 dyn·s·cm⁻⁵.
Vasoconstriction, vascular remodeling, chronic thromboembolic disease, and hypoxia all narrow or stiffen the pulmonary vessels, raising resistance.