Hypertension in the 21st Century: What We Know Now What We Need to Know

Posted By Donna Alvarado, Medical Editor

Presented by Vivek Bhalla, MD, FASN, FAHA
Assistant Professor of Medicine
Director, Stanford Hypertension Center

June 13, 2019

High blood pressure afflicts about one-third to one-half of the U.S. population. Although it’s so common, doctors still don’t know what causes it in most cases.

But they do know how to improve it. That’s important because high blood pressure is known as “the silent killer” that has few symptoms. Yet it can lead to heart attack, stroke, dementia and kidney disease.

“What is striking is that more than half of individuals that have high blood pressure don’t have it under control,” said Vivek Bhalla, MD, at a recent lecture at the Stanford Health Library.

High blood pressure is also known as hypertension. Getting it “under control” means lowering your blood pressure to meet the benchmarks for a healthy level set by doctors who study it. In the last few years, those benchmarks have changed.

What we know now

Blood pressure is a measurement of the force of blood pumped by your heart through your body’s arteries and veins. It’s usually described with 2 numbers, such as 120/80. The upper number is called systolic; the lower one is diastolic.

Two years ago, major medical organizations changed the benchmarks for healthy blood pressure. The new goal for blood pressure became 120 (for the upper number), rather than 140.

The new goal was set because a major study found people had a 25% lower risk of getting a heart attack or stroke if they lowered their blood pressure to 120 or below, compared to those who only reduced it to 140 or below.

“We have a lower blood pressure goal now,” said Dr. Bhalla, who is director of the Stanford Hypertension Center.

Between 120 and 140

The new guidelines, released in 2017, were endorsed by the American Heart Association and the American College of Cardiology. They said:

  • Normal (healthy) blood pressure is 120/80 or below
  • Prehypertension is 120-129/80
  • Stage 1 hypertension is 130-139 for the upper number and 80-89 for the lower number (either number is enough, so if you have 125/85, you fit in this category)
  • Stage 2 hypertension: over 140 for the upper number, or over 90 for the lower number

Cause unknown

High blood pressure can develop because of another condition (like kidney disease), but in 95% of cases the cause is unknown, Dr. Bhalla said. Even then, though, doctors do know what can aggravate or contribute to high blood pressure.

The most common contributors are:

  • Obesity
    About 70% to 80% of people who are obese have high blood pressure. Weight loss helps to reduce it.
  • Lack of exercise
  • Obstructive sleep apnea
    “You can test for this, and treat this,” Dr. Bhalla said. “It’s really important that message gets out.”
  • Food
    In many folks, eating food high in sodium can aggravate high blood pressure. The recommended limit for sodium intake is 2300 mg per day. Many Americans probably eat double or triple that amount, Dr. Bhalla said.
  • Chronic use of pain relievers called NSAIDs (nonsteroidal anti-inflammatory drugs)
    These common pain relievers include ibuprofen (Motrin or Advil) or naproxen (Aleve or Naprosyn).
  • Chronic use of some other drugs with a similar impact include tobacco, cocaine, amphetamines, or some nasal decongestants that contain stimulants.

Sodium debated

Some studies have found that sodium intake doesn’t matter for long-term health. “It’s a hotly debated issue,” Dr. Bhalla said. “Everybody varies, and the factors that can cause people to vary are partly environmental and partly genetic.”

He added that sodium, like the other factors, met the bar to get into guideline recommendations because “they have stood the test of time—especially in people who already have high blood pressure.”

What to do
Depending on how high your blood pressure is, there are different recommendations for getting it to a healthier level. In general:

  • If your blood pressure (upper number) is between 120 and 129, you can lower it by changing your lifestyle habits. These include:
    • Losing some weight (if you’re overweight)
    • Increasing your exercise
    • Lowering the sodium in your food
    • Asking your doctor to see if you can be checked for apnea
  • If your blood pressure (upper number) is between 130 and 139, it’s time to talk with your doctor about also taking some medicine.
    This is the blood pressure level where recommendations can vary, depending on what other risks you have for cardiovascular problems. Doctors usually recommend that patients take all the lifestyle steps listed above—and also consider taking some blood pressure medicine.
    “The higher your blood pressure is, the more benefit there is to taking blood pressure medicine,” Dr. Bhalla said.

Getting a measure

Most often, people find out they have high blood pressure when they go to the doctor and have it measured there. Often, the conditions aren’t ideal for getting an accurate result. The stress of getting to the appointment can add to the less-than-calm environment once there.

“You park. You run into the doctor’s office and are accosted by someone at the front desk. You might get your blood pressure measured, not in a quiet room, but in a hallway. Probably [this happens] simultaneously as you get a thermometer and your pulse is read, while you get asked about your medicines,” Bhalla said.

This environment can contribute to the situation known as “white coat hypertension.” Patients get a blood pressure measurement in the doctor’s office that’s higher than what they would get at home.

Resting blood pressure

The best way to get an accurate measure of blood pressure is to sit in a quiet room for 5 minutes first. Then use a machine that takes repeated measurements, 1 minute apart. This is called a resting blood pressure, or AOBP (automated office blood pressure).

“I can probably count on one hand the number of patients who had their blood pressure measured this way,” Dr. Bhalla said.

Yet the guidelines for treating blood pressure are based on blood pressure measured in this ideal environment. As a result, comparing a patient’s nonresting blood pressure (commonly taken in the doctor’s office ) to the guideline goals may not be the best practice.

“In reality, we are comparing apples and oranges in the way blood pressure is measured,” Dr. Bhalla said.

One study found that common office blood pressure measurements are about 10 points higher (for the upper systolic number) on average than true resting blood pressure. If so, some patients might get a recommendation for treatment that’s not necessary.

The new guidelines recommend that patients get a resting blood pressure measurement before considering what, if any, treatment or lifestyle changes to start.

What you need to know

Some people may have heard of white-coat hypertension, but not many know what “masked hypertension” is, Dr. Bhalla said. “Masked” refers to blood pressure that’s higher at home (out-of-office) than when you visit the doctor’s office.

“Unless you measure blood pressure at home, you would never know—you would never unmask—this,” Dr. Bhalla said. “This is both common and consequential, and currently not diagnosed very much.”

Almost 10% of the population have masked hypertension, according to a 2018 study. “It’s what we need to know,” Dr. Bhalla said. The death rate is higher in people with masked hypertension than it is in people with hypertension sustained (high at home and at the doctor’s office).

Unmasking

The best way to unmask this condition is to measure blood pressure at home. Many people use a traditional blood-pressure cuff (called a sphygmomanometer) and write down the results on paper.

The best way to get a complete picture of your blood pressure is to wear a 24-hour device on your upper arm called 24-hour ambulatory blood pressure measurement, or ABPM. Medicare and Medicaid recently announced they will cover the cost of ABPM in people suspected of having masked hypertension.

The device most commonly used now for ABPM is a bulky device that many people find uncomfortable. Many companies are racing to develop newer devices that are smaller and less bulky.

Wearable technology

Some of the newer devices fall into the category called “wearable technology” for medical applications that’s a fast-growing industry.
It’s critical for companies to validate the accuracy of new blood pressure devices. People need to be careful to check for accuracy before buying products advertised for blood pressure measurements, Dr. Bhalla said. He mentioned 2 models developed so far:

–Omron Heartguide, which is a watch with a wristband that that can measure blood pressure. This device has been approved by the US Food and Drug Administration (FDA).

–Samsung Somnotouch, a monitor the size of a small cell phone that is worn on the wrist, attached by cord to a finger sensor. It can measure blood pressure without a cuff. It has been endorsed by the European Society of Hypertension.

Many more wearable technology devices for blood pressure are coming in the next several years, Dr. Bhalla predicted. Some of them will get validation for their accuracy and be very useful for patients.

In the meantime, Dr. Bhalla urged people to be cautious and avoid models that so far haven’t been validated by an authoritative organization. He cited one device marketed by a company now defunct that promised “instant blood pressure.”

Studies found it was wrong 80% of the time.

Dr. Bhalla reported the following disclosures:

He is a member of the scientific advisory boards of 3 companies: Pyrames Inc, BioInnovate Ireland, and Relypsa.

For more information:

Vivek Bhalla, MD

Stanford Hypertension Center

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