From the Guidelines
A difference in blood pressure between the right and left upper limb is considered significant if it exceeds 10 mmHg, and the arm with the higher pressure should be used for subsequent measurements. This is based on the most recent guidelines from the 2020 International Society of Hypertension Global Hypertension Practice Guidelines 1. The difference in blood pressure between the two arms may indicate underlying vascular pathology, such as aortic dissection, subclavian steal syndrome, atherosclerotic disease, coarctation of the aorta, Takayasu arteritis, thoracic outlet syndrome, or anatomical variations.
When measuring blood pressure, it's essential to check both arms during the initial assessment, preferably simultaneously, as recommended by the 2020 guidelines 1. If a consistent difference between arms is found, further investigation may be necessary, especially if the difference is greater than 20 mmHg. The American Heart Association also recommends checking blood pressure in both arms at the first examination to detect potential conditions such as coarctation of the aorta and upper extremity arterial obstruction 1.
Key points to consider when measuring blood pressure in both arms include:
- Using the same device and technique for both arms
- Measuring blood pressure sequentially in both arms with the patient in the same position
- Considering further investigation if the difference in blood pressure between the two arms is significant, especially if accompanied by symptoms like chest pain, back pain, neurological deficits, or pulse deficits.
From the Research
Difference in Blood Pressure in Right and Left Upper Limb
- The difference in blood pressure between the right and left upper limbs has been studied in various research papers 2, 3, 4.
- A study published in 2011 found that the right arm systolic blood pressure was higher than the left arm in 62.1% of the subjects, with a mean difference of 4.15 mmHg 2.
- Another study published in 2002 found that 18% of the subjects had a difference in systolic blood pressure between both arms exceeding 10 mmHg, but this difference did not necessarily indicate any pathologic condition 3.
- A review published in 2015 discussed the prevalence of inter-arm differences in blood pressure and their association with cardiovascular disease and mortality 4.
- The studies suggest that differences in blood pressure between the right and left upper limbs are common and can have significant clinical implications 2, 3, 4.
- However, the optimal method for measuring and interpreting these differences is still a topic of research and debate 4.
- It is essential to consider the differences in blood pressure between the right and left upper limbs when diagnosing and managing hypertension 2, 3, 4.
- The American Journal of Medicine study 5 does not directly address the difference in blood pressure in the right and left upper limb, but it provides information on the treatment of hypertension, which is relevant to the management of blood pressure differences between limbs.
- The ALLHAT trial 6 compared the effects of different antihypertensive medications on blood pressure and cardiovascular outcomes, but it did not specifically address the difference in blood pressure between the right and left upper limbs.