What to check if blood pressure (BP) is different between left and right arm?

From the Guidelines

If blood pressure is different between the left and right arm, it is recommended to measure both arms at least at the first visit, and if a between-arm difference of >10 mmHg in systolic BP is recorded, use the arm with the higher BP reading for all subsequent measurements. This is based on the latest guidelines from the European Society of Cardiology, which suggest that a between-arm systolic BP difference of >10 mmHg is associated with an increased cardiovascular disease risk and may indicate arterial stenosis 1.

When measuring blood pressure, it is essential to use a validated and calibrated device, enforce the correct measurement technique, and apply a consistent approach to BP measurement for each patient 1. To measure blood pressure properly, take two consecutive readings on each arm while seated comfortably with your arm supported at heart level, and wait 1-2 minutes between measurements.

Some key points to consider when checking for blood pressure differences between arms include:

• Measuring blood pressure in both arms at least at the first visit
• Using the arm with the higher BP reading for all subsequent measurements if a between-arm difference of >10 mmHg in systolic BP is recorded
• Considering further investigation if the difference is >20 mmHg, as suggested by the 2020 International Society of Hypertension global hypertension practice guidelines 1
• Regular monitoring of both arms, particularly if you have risk factors for cardiovascular disease such as diabetes, high cholesterol, or a family history of heart disease.

It is crucial to consult a healthcare provider if a consistent difference of 10-15 mmHg or more is found between arms, as this could indicate underlying vascular problems such as peripheral artery disease, atherosclerosis, or aortic dissection.

From the Research

Checking Blood Pressure Difference between Left and Right Arm

To check if blood pressure (BP) is different between the left and right arm, several factors and guidelines should be considered:

• A significant difference in blood pressure between the right and left arm could indicate an increased risk of heart and circulatory disease, and death 2.
• National vascular disease guidelines for the over-forties advise that blood pressure measurements be taken in both arms 2.
• Inter-arm difference in blood pressure of >10 mmHg is associated with peripheral vascular disease 3.
• If a large inter-arm blood pressure difference is detected with sequential measurement, healthcare professionals should re-measure the blood pressure in the original arm 3.

Clinical Implications

The difference in blood pressure measurements between arms has several clinical implications:

• Differences in blood pressure measurements between arms are associated with other signs of vascular disease such as peripheral arterial disease or cerebrovascular disease 4.
• Differences are also associated prospectively with increased cardiovascular mortality and morbidity and all cause mortality 4, 5.
• An interarm difference in systolic blood pressure of 10 mm Hg or more is associated with an increased risk of all cause mortality 5.

Measurement and Detection

To detect and measure the difference in blood pressure between arms:

• Bilateral blood pressure measurements should become a routine part of cardiovascular assessment in primary care 5.
• The method of measurement used can affect the prevalence of an inter-arm difference 4.
• Competing aetiological explanations for an inter-arm difference should be explored, and gaps in our current understanding of this sign, along with areas in need of further research, are considered 4.