What two factors are significantly reduced in the presence of a significant stenosis?

The presence of significant stenosis in a blood vessel leads to a narrowing that restricts blood flow. This narrowing impacts hemodynamics by causing changes in both volume flow and pressure within the affected vessel.

When significant stenosis occurs, the diameter of the vessel is reduced, which ultimately decreases the volume of blood that can pass through per unit of time—referred to as volume flow. This reduced flow can lead to inadequate perfusion of tissues supplied by that vessel.

Additionally, significant stenosis increases resistance to flow due to the smaller cross-sectional area available for blood passage. According to the principles of fluid dynamics, as resistance increases, there will be a corresponding drop in pressure downstream from the stenosis. Thus, pressure is significantly affected as it falls in areas distal to the narrowed segment, leading to reduced pressure within the vessel itself.

In contrast, the factors mentioned in the other options do not have the same direct relationship with stenosis. Oxygen and nutrient flow are affected by volume flow but are not a primary measurement like pressure and flow. Heart rate and blood pressure are systemic responses that may adjust in response to various conditions but are not directly altered as a result of stenosis alone. Vascular resistance and blood viscosity relate more to the properties of blood and