From the Guidelines
Blood pressure readings can differ between arms due to various physiological and pathological factors, and a difference of more than 10 mmHg may indicate underlying health issues, therefore, it is recommended to measure blood pressure in both arms at least at the first visit and use the arm with the higher reading for subsequent measurements. A small difference of up to 10 mmHg is considered normal due to anatomical variations in blood vessel structure and the natural asymmetry of the human body 1. However, larger differences may indicate underlying health issues such as peripheral artery disease, atherosclerosis, aortic dissection, or subclavian steal syndrome, which can cause narrowing or blockage of arteries supplying one arm, resulting in reduced blood flow and lower pressure readings 1.
Some key points to consider when measuring blood pressure include:
- Measuring blood pressure in both arms at least at the first visit to detect any significant differences 1
- Using a validated and calibrated device to ensure accurate measurements 1
- Applying a consistent approach to blood pressure measurement for each patient 1
- Considering further cardiovascular evaluation if a significant difference is detected, as it may be associated with increased risk of cardiovascular events, stroke, and mortality 1
It is also important to note that the 2024 ESC guidelines for the management of elevated blood pressure and hypertension recommend measuring blood pressure in both arms at least at the first visit and using the arm with the higher reading for subsequent measurements, if a between-arm systolic BP difference of more than 10 mmHg is detected 1. Similarly, the 2020 International Society of Hypertension global hypertension practice guidelines also recommend measuring blood pressure in both arms and using the arm with the higher reading if there is a consistent difference of more than 10 mmHg 1.
From the Research
Blood Pressure Difference in Arms
- The difference in blood pressure between arms can be an indicator of underlying health issues, such as peripheral artery disease (PAD) 2, 3.
- PAD is a condition where the arteries that supply blood to the limbs become narrowed or blocked, leading to reduced blood flow and potentially causing blood pressure differences between arms 2.
- Studies have shown that individuals with PAD are at a higher risk of cardiovascular events, such as heart attacks and strokes 4, 5.
- The use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) has been shown to improve survival rates and reduce the risk of cardiovascular events in patients with PAD 6.
Potential Causes of Blood Pressure Difference
- Peripheral artery disease (PAD) is a potential cause of blood pressure difference between arms, as it can lead to reduced blood flow and narrowed arteries in the affected limb 2, 3.
- Other factors, such as aortic disease and subclavian stenosis, can also contribute to blood pressure differences between arms 3.
- The ankle-brachial index (ABI) is a useful diagnostic tool for detecting PAD and assessing the severity of the condition 4, 3.
Diagnostic and Treatment Options
- Diagnosis of PAD and other underlying conditions can be made using a combination of physical examinations, medical history, and diagnostic tests, such as the ABI and imaging studies 2, 3.
- Treatment options for PAD and related conditions may include lifestyle modifications, medication, and interventional procedures, such as percutaneous transluminal angioplasty and stenting 2, 6.
- The use of ACE inhibitors and ARBs has been shown to be beneficial in reducing the risk of cardiovascular events and improving survival rates in patients with PAD 5, 6.