Definition of blood pressure readings changed

Doctors change how they evaluate blood pressure numbers

·         By Geraldine A. Collier
Correspondent

Posted Jan. 27, 2016 at 8:55 AM 

If you were diagnosed some years ago with hypertension – high blood pressure – you might just want to have another conversation with your doctor.

If you have been told you are “pre-hypertensive,” you might also want to talk to your doctor.

Not all that long ago, you were considered to be healthy or “normal” if your blood pressure measured 120/80 to 139/89 – nothing to worry about unless that last reading went higher.

We may not have changed, but the standard way the medical world uses to evaluate us has. High is still high, but what once was normal is now labeled “pre-hypertensive” and only abut half of us over the age of 18 are considered to be normal with blood pressure lower than 120/80. The rest of us – millions and millions of us – have to worry about our chances of having a stroke, cardiovascular problems and/or kidney disease.

Not only has the definition of blood pressure readings changed, but so has the best method for detecting the problem and the treatments prescribed. The goal we need to reach in order to improve our chances of staying healthy? Well that’s a moving target.

Let’s look at blood pressure numbers.

The systolic (top number) measures “the pressure in the arteries when the heart muscle contracts,” according to the American Heart Association, while the diastolic (bottom number) measures “the pressure in the arteries when the heart muscle is resting between beats and refilling with blood.”

“I tell people to think about garden hoses,” explained Dr. Kenneth Kronlund, an internist and quality chief for adult primary care at Reliant Medical Group.

“Say that you have a sprinkler out in the garden and you turn the spigot on and the hose fills up and then you turn the spigot off and the sprinkler still sprinkles until the pressure goes away.

“The pressure at the top (systolic) is the maximum pressure when the garden hose is as distended as it will get and the bottom number (diastolic) is as low as it will get before you turn the spigot on again,” added Dr. Kronlund.

If you pre-hypertensive – 120/80 to 139/89 – your doctor will probably recommend lifestyle changes, including weight loss, although some physicians will also ask you to take medication while you are making those changes.

If you are diagnosed with high blood pressure, you’re going to have to take a pill for the rest of your life. However, that pill isn’t the same as the pill you would have been prescribed some years ago. (You might want to talk to your doctor about that.)

“The drugs that we used 10 years ago commonly were beta blockers drugs (Metoprolol, for instance), but beta blockers have fallen way down in preference,” said Dr. Kronlund. Instead, diuretics, ACE inhibitors or calcium channel blockers are likely to be the medications prescribed today.

By the way, that blood pressure reading taken in your doctor’s office shouldn’t be the final word.

In October, the U.S. Preventative Services Task Force recommended that before starting any treatment, elevated blood pressure readings taken in a doctor’s office should be confirmed by a number of outside readings.

The preferred method for doing this involves a device called an ambulatory blood pressure monitor, which involves wearing a cuff attached to a small, portable machine that records blood pressure over a period of 12 to 48 hours.

However, USPSTF says home blood pressure cuffs, which measure blood pressure in the upper arm, are OK for diagnosis when used twice in the morning and twice in the evening for a minimum of three, but preferably seven consecutive days. Many, but not necessarily all, primary care physicians do loan out these blood pressure cuffs for home testing.

Like many doctors, Dr. Stephen Martin, who specializes in family medicine at UMass Memorial Medical Center’s Barre Family Health Center, also recommends that people who have high blood pressure or are pre-hypertensive purchase a cuff monitor – not a wrist monitor – to keep track of their readings in between visits to the doctor.

They are available at most drugstores, but you first might want to ask your doctor for a recommendation or check out this month’s issue of Consumer Reports, according to Dr. Martin. It’s also a good idea to have your doctor calibrate the cuff monitor to make sure it’s accurate.

Two major studies have looked at different patient populations who are at high risk for serious or even deadly consequences from high blood pressure: non-diabetics in the very recent Systolic Blood Pressure Intervention Trial - SPRINT - and diabetics in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) clinical trial.

The SPRINT study enrolled 9,361 patients – 56 came from UMass Memorial Medical Center. They were at least 50 years old, with a systolic blood pressure measurement of at least 130 to 180; any type of cardiovascular disease other than stroke; or chronic kidney disease, or a 10-year-risk of cardiovascular disease of 15 percent or greater based on the famous Framingham study or an age of 75 years or older. (Yup, living longer is definitely a risk factor.)

“This is not some arcane group of people with an obscure disease,” said. Dr. Gerard P. Aurigemma, a cardiologist at UMass Memorial who was the principal investigator for the SPRINT trial at that site.

“This is bread and butter adult internal medicine,” said Dr. Aurigemma. “These are the patients that we see day in and day out in the office. This is one reason why this study is so important, because it helps us to understand how best to treat patients that we see on a regular basis.

“Clinical data has always told us that small blood pressure reductions have a big payoff in terms of reduction in events, particularly stroke,” added Dr. Aurigemma. “So, the results of SPRINT were not very surprising to me. It was the magnitude of the benefit that was the surprise.”

While patients in the SPRINT study who were prescribed two blood pressure medications to bring their blood pressure below 140 had some benefit occur, patients who were prescribed three blood pressure medications to bring their blood pressure below 120 had significantly reduced cardiovascular events by 30 percent and all-cause mortality by nearly 25 percent.

Hopefully, the SPRINT study will bring a uniform voice on targets for blood pressure,” said Dr. Glenn R. Kershaw, a nephrologist (kidney disease specialist) who directs the Hypertension Clinic at UMass Memorial Medical Center.

“When we can look at the different complications and the different subsets of patients – that is when the experts will come out with some guidelines and some recommendations for each of the subsets of patients, and the medical community will have a more uniform voice on what these blood pressure targets should be.”

However, one puzzlement remains for those who manage high blood pressure in their patients. In studying diabetics’ responses to blood pressure lowering, the ACCORD study, which was done several years ago, showed that patients whose blood pressure was brought below 140 derived benefit, but no significant further benefits were found for those diabetics taking three blood pressure medications to drop blood pressure readings to below 120.

Some experts believe that the ACCORD study, which was smaller than the SPRINT study, would have shown similar benefits for those whose blood pressure was pushed to below 120 if the study had been larger. However, no one knows for sure.

“I think we need to be aware of the fact that one size doesn’t necessarily fit all,” said Dr. Kershaw. “The most important thing is that a doctor knows his patient and works with his patient and they have a partnership in deciding what target blood pressure they want to achieve.”