Vascular resistance

Vascular resistance is the resistance that must be overcome to push blood through the circulatory system and create blood flow. The resistance offered by the peripheral circulation is known as the systemic vascular resistance (SVR), while the resistance offered by the vasculature of the lungs is known as the pulmonary vascular resistance (PVR). Vascular resistance is used by physicians to calculate cardiac function.

Overview

Vascular resistance is a term used to define the opposition to flow that must be overcome to push blood through the circulatory system. The resistance offered by the peripheral circulation is known as the systemic vascular resistance (SVR). Conversely, the resistance offered by the vasculature of the lungs is known as the pulmonary vascular resistance (PVR).

Calculation

Vascular resistance can be calculated using Ohm's law. It is the difference in blood pressure across the systemic circulation, divided by cardiac output.

Factors affecting vascular resistance

Several factors can affect vascular resistance, including blood viscosity, blood vessel length, blood vessel diameter, and the number of blood vessels.

Clinical significance

Vascular resistance is an important aspect of cardiovascular health. Abnormal vascular resistance can lead to conditions such as hypertension and heart failure.

See also

• Blood pressure
• Cardiac output
• Hypertension
• Heart failure