Measuring one’s blood pressure (BP) is no more just about inflating a cuff in the upper arm and getting a number.
The simple task of blood pressure measurement — which used to be performed using the old mercury manometer — has changed so dramatically over the years that, today, there are innumerable ways in which a doctor looks at blood pressure values, for giving better clinical outcome to his patients.
New research published in the March issue of the Journal of American of Medicine says that even modest differences in systolic blood pressure readings as 10 or 15 mm Hg between both arms (inter-arm) could predict a significantly increased future cardiovascular disease (CVD) risk.
This new study examined 3,390 participants aged 40 years and older from the Framingham Heart Study, all of whom were free of CVD at baseline.
So does that mean blood pressure should be measured in both arms in routine clinical practice by primary physicians? “No, inter-arm BP reading may be required only if the patient is already hypertensive and or has sufficient risk factors such as diabetes, overweight, or high cholesterol. A variation could indicate some blockage in the arteries or general vascular disease,” says Tiny Nair, senior cardiologist.
A doctor may use the ankle-brachial index (ABI) test if he suspects that the patent could be at CVD risk.
The ABI compares the blood pressure measured at the ankle to the arm, a non-invasive way to predict if a patient has periphery artery disease (PAD) or narrowed arteries in arms or legs, which could put him at a high risk for heart attack or stroke.
Many cardiologists prefer 24-hour ambulatory blood pressure monitoring (ABPM) to clinical BP readings to predict if a patient has a higher risk of CVD or stroke.
The instrument, worn by a patient like a watch, continuously monitors and traces the blood pressure variations as he goes through a 24-hour sleep-wake cycle.
“Blood pressure readings in a 24-hour cycle normally spike through the day and should dip at night. ABPM gives us crucial information if a patient is a ‘dipper’ or ‘non-dipper’ at night, because non-dippers are at a higher risk of CVD,” Dr. Nair says.
The past five years saw the evolution of a newer and more accurate way of monitoring BP — the Central Aortic Systolic Pressure or CASP. The device measures pressure inside the aorta, the largest artery of the heart, and is a stronger predictor of CVD/stroke risk than a normal BP reading.
