What is the preferred method for measuring blood pressure, radial or brachial, in the diagnosis and management of hypertension?

Brachial Blood Pressure Measurement is Superior to Radial for Hypertension Management

Brachial artery blood pressure measurement using an upper arm cuff is the preferred standard method for diagnosing and managing hypertension, while radial (wrist) monitors are not recommended for routine clinical use. 1

Why Brachial Measurement is Preferred

Evidence-Based Advantages

• Brachial artery pressure is the measure used in all epidemiological studies of high blood pressure and its consequences 2, 1
• The standard location for blood pressure measurement is the upper arm, with the stethoscope at the elbow crease over the brachial artery 2
• Brachial measurements are more reliable and less susceptible to positioning errors 1
• Most validated clinical guidelines for hypertension diagnosis and management are based on brachial artery measurements 1

Limitations of Radial (Wrist) Measurement

• Wrist monitors are explicitly "not recommended for routine clinical use" by major guidelines 2, 1
• Wrist monitors are highly position-sensitive, requiring precise placement at heart level 2, 1
• A systematic error is introduced by the hydrostatic effect of differences in the position of the wrist relative to the heart 2
• Most wrist monitors that have been tested have failed validation studies 1
• Pressure values vary substantially in different parts of the arterial tree - systolic pressure generally increases in more distal arteries while diastolic pressure decreases 2

Proper Brachial Blood Pressure Measurement Technique

Patient Preparation

• Patient should be seated comfortably after 5 minutes of rest 2
• Avoid exercise, caffeine, and tobacco for at least 30 minutes before measurement 2
• Empty bladder if needed 2
• Patient should be seated with legs uncrossed and back supported 2
• Arm should be supported at heart level 2
• Remove clothing at the location of cuff placement (avoid rolling up sleeves) 2

Measurement Protocol

• Use a validated device (oscillometric or auscultatory) 2
• Select appropriate cuff size based on arm circumference 2
• Take 3 measurements with 1 minute between them 2
• Calculate the average of the last 2 measurements 2
• Measure BP in both arms initially; if difference >10 mmHg consistently, use the arm with higher BP 2

Special Circumstances

When Wrist Monitors Might Be Considered

• For patients with very large arm circumference where proper cuff sizing is impossible 1
• Only validated wrist devices with position sensors should be used in these cases 1
• The wrist must always be positioned at heart level during measurement 2

Central Blood Pressure Considerations

• Central (aortic) blood pressure may differ from brachial measurements and might better predict cardiovascular outcomes 3, 4, 5
• However, central BP measurement techniques are not yet standardized for routine clinical use 2
• The 2024 ESC guidelines note that central BP measurement requires further investigation before routine clinical application 2

Clinical Implications

Diagnosis of Hypertension

• Hypertension is diagnosed when office systolic BP is ≥140 mmHg and/or diastolic BP is ≥90 mmHg following repeated examination 2
• Diagnosis should typically be confirmed across 2-3 office visits at 1-4 week intervals 2
• When possible, out-of-office measurements should confirm the diagnosis 2

Monitoring Considerations

• Home blood pressure monitoring should use validated upper arm (brachial) devices 2, 1
• Multiple readings should be taken and averaged for more accurate assessment 1

By following these evidence-based recommendations for brachial blood pressure measurement, clinicians can ensure more accurate diagnosis and management of hypertension, ultimately improving patient outcomes related to cardiovascular morbidity and mortality.