From the Guidelines
A blood pressure difference of 20 mm Hg between arms should be considered clinically significant and warrants further evaluation by a healthcare provider. This finding may indicate peripheral vascular disease, specifically subclavian artery stenosis, aortic dissection, or other vascular abnormalities 1. According to the 2020 international society of hypertension global hypertension practice guidelines, if the difference is >20 mm Hg, consideration of further investigation is recommended 1.
Key Considerations
- The 2024 ESC guidelines for the management of elevated blood pressure and hypertension also recommend measuring office BP in both arms at least at the first visit, as a between-arm systolic BP difference of >10 mmHg is associated with an increased CVD risk and may indicate arterial stenosis 1.
- A consistent inter-arm difference of 10-15 mm Hg or greater is considered clinically significant and is associated with increased cardiovascular risk.
- The difference occurs because narrowing in the arteries supplying one arm can reduce blood flow and pressure in that limb compared to the other side.
Recommended Course of Action
- I recommend scheduling an appointment with your primary care physician within the next 1-2 weeks for further evaluation.
- They will likely perform additional blood pressure measurements to confirm this finding and may order imaging studies such as a duplex ultrasound, CT angiography, or MRI angiography to assess your vascular system.
- While waiting for your appointment, continue taking any prescribed blood pressure medications as directed and monitor your blood pressure at home, recording readings from both arms.
From the Research
Blood Pressure Discrepancy Between Arms
- A study published in 1991 2 found that the incidence of systolic pressure difference greater than or equal to 20 mmHg between arms was higher in patients with peripheral vascular disease (PVD) compared to those with coronary artery disease (CAD) or control subjects.
- The study also found that patients with PVD had a greater incidence of right and left arm difference for mean and diastolic blood pressures.
- However, the study noted that neither the right nor the left arm blood pressure was consistently higher in patients with a systolic difference greater than 10 mmHg.
Potential Causes and Implications
- Atherosclerotic occlusive disease of the lower extremities (ASO-LE) may be a contributing factor to blood pressure discrepancies between arms 3.
- The use of aspirin has been found to be a positive predictor of successful crossing in chronic total occlusions (CTOs) 4.
- A study published in 2019 5 found that ankle systolic blood pressure was higher than arm blood pressure in the general population, while diastolic blood pressure was similar.
- Vascular surgery interventions, including revascularization, may be necessary for patients with advanced vascular disease or lifestyle-limiting claudication 6.
Clinical Considerations
- Blood pressure measurements should be taken in both arms to detect any discrepancies 2.
- Patients with a history of vascular disease or risk factors for atherosclerosis should be monitored closely for blood pressure discrepancies and other cardiovascular complications 3, 6.
- Further research is needed to fully understand the relationship between arm and leg blood pressure readings and to inform clinical practice 5.