Updated blood pressure guidelines help assess risk
The American College of Cardiology (ACC) and American Heart Association (AHA) lowered the threshold for diagnosing hypertension in November 2017, and this means many Americans now fall into a higher risk category than before — even if their numbers haven’t changed.
Based on new guidelines for the detection, prevention, management and treatment of high blood pressure published by the ACC and the AHA, 46 percent of the general U.S. population is now considered to have some level of high blood pressure — an increase of 14 percent from the old designations.
A committee of 21 members from 11 different organizations spent over three years conducting a rigorous review, the first since 2003. Some of their most important recommendations include:
Revised threshold for hypertension
Blood pressure is reported using two numbers. The systolic reading, or top number, refers to the pressure when the heart contracts and sends blood through the arteries. Diastolic pressure, the bottom number, is measured when the heart relaxes between beats.
High blood pressure is now defined as 130 mm Hg and higher for systolic blood pressure, or 80 mm Hg and higher for diastolic, down from the old definition of 140/90 and higher. Category names have also been revised to more accurately reflect an individual’s risk.
According to the committee’s chair, epidemiologist and physician Dr. Paul Whelton, “Normal BP is what it’s always been, less than 120 for systolic pressure, and less than 80 for diastolic. But the last comprehensive guidelines had a designation called prehypertension that went from 120 to 139 systolic and 80 to 89 diastolic. We didn’t like that terminology because it could be interpreted as ‘I don’t have hypertension yet and I don’t really need to worry or do anything about it.’ And we thought that was misleading.”
Based on the evidence, it has been shown that complications can occur at lower numbers than previously recognized. Whelton says that levels from 130-139/80-89 double the risk of cardiovascular complications compared to normal levels. By lowering the definition of what is considered hypertension, intervention — whether non-drug lifestyle changes or drug therapy — can be started sooner, before further damage is done or risk increases. “We felt that if people were at higher risk and would receive benefits from treatment, then they ought to know about it,” Whelton said.
Systolic levels from 120–129 with diastolic less than 80 is now labeled as “elevated.” Levels from 130–139 systolic or 80–89 diastolic are considered Stage 1 Hypertension. And 140 or higher systolic or 90 or higher diastolic is Stage 2 Hypertension. (A systolic reading of higher than 180 and/or diastolic of higher than 120 is considered a hypertensive crisis and medical guidance should be sought immediately.)
When to treat
People who have had a cardiovascular incident such as heart attack or stroke are automatically considered high risk and should receive treatment. For others, the decision to treat should be based on results from a risk calculation that considers factors including systolic blood pressure, age, gender, health and family history, lipid levels and lifestyle to assess a person’s risk of heart attack or stroke within the next 10 years. You can find a do-it-yourself calculator at the ACC’s website to assess your own risk.
Treatment can consist of either drug or non-drug interventions, or both. Despite the large increase in the percentage of those now considered at risk, newer and more specific criteria for treatment mean the increase in recommendation for antihypertensive drug therapy is only about 2 percent over previous guidelines.
Importance of accurate measurement
Blood pressure readings can vary considerably from one reading to the next. The committee emphasized ways to improve accuracy, including quiet and silent resting before and during measurement, proper positioning, correct cuff size and averaging multiple measurements taken over time in both in-office and out-of-office settings.
Treatment goal lowered
Previous guidelines recommended getting blood pressure down to 140/90 or below as a goal for those being treated. But the committee unanimously felt there was very strong evidence to support a goal of 130/80 or under for most people. “We believe if this guidance is followed, it will improve health for individuals and for the nation,” Dr. Whelton said.
Lifestyle changes that lower blood pressure
Get regular physical activity
FOCUS ON NUTRITION
Eat potassium-rich vegetables such as spinach, cantaloupe and broccoli
Aim for 1,500 mg of sodium or less per day
For men, not more than 2 drinks per day; for woman, 1
Losing just a few pounds can make a big difference
If you smoke, stop
Meditation and rest help lower blood pressure