What is pulse pressure?

Pulse Pressure: Definition and Clinical Significance

Pulse pressure is the difference between systolic and diastolic blood pressure measurements, calculated by subtracting diastolic from systolic blood pressure. 1 This derived hemodynamic parameter provides important information about cardiovascular health beyond what individual systolic and diastolic readings alone can offer.

Definition and Measurement

Pulse pressure is calculated using a simple formula:

• Pulse Pressure = Systolic Blood Pressure - Diastolic Blood Pressure

For example:

• If blood pressure is 120/80 mmHg, pulse pressure = 40 mmHg
• If blood pressure is 160/70 mmHg, pulse pressure = 90 mmHg

Physiological Basis

Pulse pressure arises from the interaction between:

• Cardiac ejection (stroke volume)
• Properties of the arterial circulation, particularly arterial compliance
• Wave reflection phenomena in the arterial tree

As the heart contracts, it ejects blood into the aorta, creating a pressure wave that travels through the arterial system. The elasticity of the arteries helps dampen this pressure wave. When arteries become stiffer (less compliant), pulse pressure increases 1, 2.

Clinical Significance

Age-Related Changes

• Pulse pressure naturally increases with age due to arterial stiffening
• In younger individuals (<55 years), systolic and diastolic pressures are both important predictors of cardiovascular risk
• In older individuals, systolic pressure and pulse pressure become stronger predictors of risk 1

Predictive Value for Cardiovascular Events

• High pulse pressure (≥60 mmHg) is associated with a 57% increased risk of major cardiovascular events, independent of other risk factors 3
• Pulse pressure is particularly predictive in middle-aged and elderly hypertensive patients with cardiovascular risk factors 1
• It serves as a marker of arterial stiffness and advanced organ damage 1

Clinical Conditions Associated with Widened Pulse Pressure

• Arteriosclerosis and vascular stiffening (most common cause)
• Isolated systolic hypertension, especially in the elderly
• Aortic regurgitation
• Hyperthyroidism
• Other high-output cardiac states 2

Pulse Pressure in Different Populations

Elderly Patients

• As people age, systolic pressure tends to rise while diastolic pressure falls, resulting in increased pulse pressure 1
• In elderly patients with systolic hypertension, increased pulse pressure is a marker of arterial stiffness and cardiovascular risk 1

Young Patients with Isolated Systolic Hypertension

• In younger individuals, elevated systolic pressure may be due to increased wave amplification between the aorta and brachial artery
• This can result in high peripheral (brachial) systolic pressure while central aortic pressure remains normal 1

Clinical Application

While pulse pressure provides valuable prognostic information, current hypertension management guidelines still recommend using systolic and diastolic blood pressures for:

• Classification of hypertension
• Risk assessment
• Treatment decisions 1

However, pulse pressure should be considered as an additional risk marker, particularly in:

• Elderly patients with isolated systolic hypertension
• Patients with evidence of target organ damage
• Those with multiple cardiovascular risk factors 1, 3

Normal vs. Abnormal Values

While no definitive cutoff values have been established for all age groups, figures such as:

• 50-55 mmHg have been suggested as thresholds for concern 1
• Pulse pressure ≥60 mmHg is generally considered elevated and associated with increased cardiovascular risk 3

It's important to note that normal pulse pressure varies with age, and what might be considered elevated in a young adult may be normal in an elderly person.