Blood Pressure Checking Reform Needed, Says Study

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Regular monitoring of a patient’s blood pressure is a simple, but important physiological test that can speak volumes about a patient’s current and future health. However, recent studies show that when a doctor or his assistant takes a single blood pressure reading from just one arm, that he or she may be missing out on some useful additional information that could forewarn of impeding disease. Therefore, studies show that reform is needed toward how doctors check their patients' blood pressures.

According to the Centers for Disease Control (CD) an estimated one in three U.S. adults (68 million) have high blood pressure. High blood pressure is the leading cause of death because it increases the risk of heart disease and stroke.

What is blood pressure?

Blood pressure is the force of blood against your arterial walls as it circulates through your body, which normally rises and falls throughout the day. However, when blood pressure remains relatively high constantly throughout the day, it causes damage to the body.

Among the ways that high blood pressure can damage your health include:

1. Hardening of the arteries, which then decreases the flow of blood and oxygen to the heart resulting in:

• Chest pain, also called angina.

• Heart failure, which occurs when the heart can't pump enough blood and oxygen to your other organs.

• Heart attack, which occurs when the blood supply to your heart is blocked and heart muscle cells die from a lack of oxygen.

2. High blood pressure that can burst or block arteries that supply blood and oxygen to the brain, causing a stroke.

How blood pressure is measured

Blood pressure is measured using a blood pressure cuff called a sphygmomanometer, which consists of an inflatable bladder that compresses against an artery at a pressure higher than that of the blood pumping against the artery’s walls. When air from the cuff is slowly released, eventually the arterial pressure will equal the cuff pressure and blood will flow through the artery. The moment the pressures are equal can be noted by listening to the blood pump through the artery making a swooshing sound that can be heard using a stethoscope placed between the cuff and the artery. This first sound is referred to as your systolic pressure reading. As more air is released from the cuff the swooshing sound will fade away until it is inaudible and this is referred to as your diastolic pressure reading.

Your systolic and diastolic blood pressure readings are recorded as paired numbers such as 120/80, which is typically read as “one hundred and twenty over eighty.” A normal blood pressure reading consists of a systolic value of less than 120 and a diastolic value of less than 80.

However, when the systolic value is 120-139 and the diastolic value is 80-89, then you are considered to be at risk for developing high blood pressure (hypertension) and are labeled as being “pre-hypertensive.” When the systolic value is 140 or higher and the diastolic value is 90 or higher, then you are diagnosed as having high blood pressure. Diagnoses of being pre-hypertensive or hypertensive requires medical attention to bring your blood pressure down to normal levels.

While taking a single or multiple readings of a patient’s blood pressure from the one arm (it can vary between individuals) that is found to have the highest readings has been the standard for many years, new research shows that taking the blood pressure from both arms and comparing the systolic number differences is just as important.

Blood pressure studies

Previous reports published earlier this year in the medical journal The Lancet have shown that differences in systolic blood pressure of 10 mm Hg or more or 15 mm Hg or more between arms have been associated with peripheral vascular disease—a condition that involves a narrowing of the arteries in the extremities, particularly the legs and feet. Furthermore, marked differences between left and right arm systolic values can indicate kidney disease, diabetes and heart defects.

In the most recently published study investigating the effect on heath in patients with systolic values that differ markedly between the arms, researchers from the UK report in the March issue of the British Medical Journal (BMJ) their findings that extends the cardiac-related health and mortality implications of divergent systolic blood pressure readings (full text available free online).

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What the researchers found was that:

• In a primary care setting and population of patients with hypertension, an inter-arm difference in systolic blood pressure of 10 mm Hg or more or 15 mm Hg or more was associated with an increased risk of cardiovascular and mortality.

• For people with hypertension but no pre-existing cardiovascular disease, an inter-arm difference in systolic blood pressure seems to confer a level of risk equivalent to that of people with hypertension and pre-existing cardiovascular disease.

The authors of the paper concluded that their results and those from previous studies argue that blood pressure measurement in both arms should become a routine part of cardiovascular assessment in primary care and should follow the 2007 guidelines for treating hypertension as published in the European Heart Journal.

Blood pressure check reform recommendations

The European Heart Journal makes the following recommendations for how a physician should check their patients’ blood pressures:

• Allow the patients to sit for several minutes in a quiet room before beginning blood pressure measurements.

• Take at least two measurements spaced by 1–2 minutes, and additional measurements if the first two are quite different.

• Use a standard bladder (12–13 cm long and 35 cm wide) but have a larger and a smaller bladder available for fat and thin arms, respectively. Use the smaller bladder in children.

• Have the cuff at the heart level, whatever the position of the patient.

• Use phase I and V (disappearance) Korotkoff sounds to identify systolic and diastolic BP, respectively.

• Measure BP in both arms at first visit to detect possible differences due to peripheral vascular disease. In this instance, take the higher value as the reference one.

• Measure BP 1 and 5 min after assumption of the standing position in elderly subjects, diabetic patients, and in other conditions in which postural hypotension may be frequent or suspected.

• Measure heart rate by pulse palpation (at least 30 sec) after the second measurement in the sitting position.

Therefore, on your next visit to see your doctor, pay attention to how your blood pressure is taken and be sure to discuss with him your concerns about differences between the systolic values in your blood pressure readings and to whether they may indicate peripheral artery disease and/or an increased risk of cardiovascular disease.

Image Source: Courtesy of MorgueFile

References:

“Association of a difference in systolic blood pressure between arms with vascular disease and mortality: a systematic review and meta-analysis” The Lancet Volume 379, Issue 9819 pp. 905 - 914, 10 March 2012; Christopher Clark et al.

“The difference in blood pressure readings between arms and survival: primary care cohort study”; BMJ 2012; 344: e1327; Christopher E Clark, Rod S Taylor, Angela C Shore and John L Campbell.

“2007 Guidelines for the management of arterial hypertension” European Heart Journal; Volume 28 issue 12; Giuseppe Mancia et al.

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