Is the blood pressure same on both arms? Cardiology Basics

Is the blood pressure same on both arms? Cardiology Basics

Guidelines on hypertension by medical societies generally recommend measurement of blood pressure in both arms in the initial visit. They also suggest that the arm with higher blood pressure recording should be used to record blood pressure in subsequent visits. It is often mentioned that there is a small difference in the blood pressure between the arms and usually it is the right arm blood pressure which is higher.

The origin of brachiocephalic artery is in line with the ascending aorta. It is presumed that the force of ejection of the left ventricle is conveyed more to the right subclavian artery for this reason.

When there is a significant difference in the blood pressure between the arms, this explanation is not enough. Partial obstruction to one upper limb artery is an important reason for lower blood pressure in that arm. Obstruction of upper limb arteries is a pointer to vascular disease elsewhere in the body also. They are more prone to have myocardial infarction and stroke due to associated coronary artery disease and cerebrovascular disease.

Important risk factors for peripheral arterial disease are hypertension, diabetes mellitus, dyslipidemia, obesity, and smoking. Advancing age, heredity and male gender are non-modifiable risk factors. Difference in blood pressure between the arms is more likely in the presence of risk factors.

Another important serious disease which has to be thought of in a person with pain in the chest or upper back is aortic dissection. Aortic dissection is a tear in the intima of the aorta. Blood seeps into the wall of the aorta and spreads along the wall of the aorta. As this progresses, it can obstruct the openings of the major branches. In those coming to emergency department with severe chest pain or upper back pain, if there is a large difference in the blood pressure between the arms, this serious condition has to be thought of.

Among the arterial diseases, an important variety is obstruction due to inflammation of the aorta, known as aortoarteritis. The disease is also known as Takayasu arteritis, after the person who described it. It is also known as pulseless disease as arm pulses may be absent due to obstruction of the upper limb arteries. It is a progressive disease with more and more arteries getting affected as time passes.