Study: Fluctuating Blood Pressure Could Be Bad for Those With Alzheimer’s

The study published in the American Heart Association journal Hypertension sought to add a new understanding about the links between Alzheimer’s, the heart and blood vessels. Past research shows blood pressure variability could be connected to stroke, and researchers of the new study wanted to see if there was a similar link between yo-yoing blood pressure and Alzheimer’s.

Researchers looked at data from a randomized trial of 460 people who were 72 on average and had “mild-to-moderate” Alzheimer’s. After 1 1/2 years, people who scored the highest in blood pressure variability had deteriorated more on a cognitive scale than those with the least amount of variability.

Data on day-to-day blood pressure fluctuations was only available for 46 patients, and in that smaller group, researchers also found “significant associations” between variable blood pressure and dementia after one year, but not after 1 1/2 years.

“Everybody already knows that it’s important to control blood pressure in midlife to reduce your risk of Alzheimer’s later, but this tells us it’s still important to regulate blood pressure when you already have dementia,” said the study’s senior author, Dr. Jurgen Claassen. “More fluctuations might affect whether cognitive function declines more slowly or rapidly.”

Future research is needed to find out if blood pressure variability is truly causing the dementia to worsen, said Claassen, associate professor at Radboud University Medical Center in Nijmegen, Netherlands.

“If that’s true, medication or lifestyle (changes) might help slow down disease progression,” he said. “But it could also be the other way around … that the dementia itself might lead to blood pressure variability, which could be a signal that helps you identify people with Alzheimer’s.”

He also called for studies on how sleep, diet and exercise might help stabilize blood pressure.

“Alzheimer’s treatments are limited at this point, and even a small difference in slowing down the disease’s progression can mean a lot,” Claassen said. “It could be the difference between whether or not a patient is still able to drive a car and live independently.”

Nearly 6 million Americans have been diagnosed with Alzheimer’s disease, including 200,000 people under the age of 65. It’s the most common cause of dementia and is the sixth-leading cause of death in the United States.

Research on the link between blood pressure and Alzheimer’s is relatively new, but a 2018 study in the journal Neurology found the brains of older people with higher blood pressure were more likely to have “tangles,” or twisted strands of protein that are common markers of Alzheimer’s.

Jeffrey Keller, director of the Institute for Dementia Research and Prevention at Louisiana State University in Baton Rouge, called the new research “an important study that continues to fine-tune our understanding of Alzheimer’s and dementia.”

“There is a lot of evidence that fluctuations in blood pressure of people who do not have hypertension are related to adverse cardiac events, so it is not surprising that variability in blood pressure is also linked to negative cognitive function,” said Keller, who was not involved in the new study.

He said the research was limited by its small sample size and by being observational. But he noted the study paves the way for future research, including large studies that use wearable devices to track people’s day-to-day blood pressure variability.

“We’re finding more and more that there is a direct link between blood pressure in the periphery of an individual and the ability of their brain to stay healthy. It’s important for people to stay on top of their blood pressure – not just for their general health, but specifically for their brain.”

Source: HealthDay

Advertisements

Blood Pressure Monitoring May One Day be Easy as Taking a Video Selfie

Blood pressure monitoring might one day become as easy as taking a video selfie, according to new research in Circulation: Cardiovascular Imaging, an American Heart Association journal.

Transdermal optical imaging measures blood pressure by detecting blood flow changes in smartphone-captured facial videos. Ambient light penetrates the skin’s outer layer allowing digital optical sensors in smartphones to visualize and extract blood flow patterns, which transdermal optical imaging models can use to predict blood pressure.

Finding an accessible, easy way to monitor blood pressure is important given that nearly half of American adults have high blood pressure and many don’t even know they have it, according to the American Heart Association.

“High blood pressure is a major contributor to cardiovascular disease — a leading cause of death and disability. To manage and prevent it, regular monitoring of one’s blood pressure is essential,” said study lead author Kang Lee, Ph.D., professor and research chair in developmental neuroscience at the University of Toronto in Canada. “Cuff-based blood pressure measuring devices, while highly accurate, are inconvenient and uncomfortable. Users tend not to follow American Heart Association guidelines and device manufacturers’ suggestion to take multiple measurements each time.”

Lee and his colleagues measured the blood flow of 1,328 Canadian and Chinese adults by capturing two-minute videos using an iPhone equipped with transdermal optical imaging software.

The researchers compared systolic, diastolic and pulse pressure measurements captured from smartphone videos to blood pressure readings using a traditional cuff-based continuous blood pressure measurement device.

The researchers used the data they gathered to teach the technology how to accurately determine blood pressure and pulse from facial blood flow patterns. They found that on average, transdermal optical imaging predicted systolic blood pressure with nearly 95% accuracy and diastolic blood pressure with pulse pressure at nearly 96% accuracy.

The technology’s high accuracy is within international standards for devices used to measure blood pressure, according to Lee.

Researchers videoed faces in a well-controlled environment with fixed lighting, so it’s unclear whether the technology can accurately measure blood pressure in less controlled environments, including homes. Also, while the study’s participants had a variety of skin tones, the sample lacked subjects with either extremely dark or fair skin tones. Lee and colleagues are also looking into reducing the needed video length from 2 minutes to 30 seconds, in order to make the technology more user-friendly.

People in the study all had normal blood pressure. “If future studies confirm our results and show this method can be used to measure blood pressures that are clinically high or low, we will have the option of a contactless and non-invasive method to monitor blood pressures conveniently – perhaps anytime and anywhere – for health management purposes,” Lee said.

“This study shows that facial video can contain some information about systolic blood pressure,” said Ramakrishna Mukkamala, Ph.D., Circulation Imaging editorial author and professor in the Department of Electrical and Computer Engineering at Michigan State University in East Lansing. “If future studies could confirm this exciting result in hypertensive patients and with video camera measurements made during daily life, then obtaining blood pressure information with a click of a camera may become reality.”

Source: American Heart Association


Today’s Comic

Blood Pressure Control Is Key to Avoid a Second Stroke

Serena Gordon wrote . . . . . . . . .

If you’ve already had one stroke, your risk for another is much higher. But new research found that well-controlled blood pressure can reduce that risk by about 20%.

The study authors suggested maintaining a blood pressure of 130/80 mm Hg or less.

“Intensive blood pressure control of at least less than 130/80 mm Hg is recommended for secondary stroke prevention,” said Dr. Kazuo Kitagawa, the study’s lead author. Kitagawa is a professor and chair of neurology at Tokyo Women’s Medical University in Japan.

While 120/80 mm Hg or lower might be an even better target, Kitagawa noted that only about one-third of people in the current study were able to achieve a level that low, despite being on an average of almost three blood pressure-lowering drugs.

He said that patients often worry that their blood pressure might drop too low, and there are side effects that can be associated with aggressive blood pressure reduction.

The new research was published online July 29 in JAMA Neurology.

The author of an editorial accompanying the study, Dr. Craig Anderson, said lowering blood pressure “is relatively straight forward.” But to effectively control blood pressure, doctors often need to prescribe multiple medications, though not all doctors will do so, he said. Anderson is a professor of neurology at the University of New South Wales in Sydney, Australia.

“Perhaps doctors have a tendency to be conservative in their use of antihypertensive medications, particularly in older, frailer people, because of the genuine concern about causing side effects, such as a fall from dizziness leading to a hip fracture,” he noted.

Anderson said the most common side effects of blood pressure-lowering drugs are mild, such as dizziness, ankle swelling and fatigue. These can often be avoided by modifying the drug dosage, he said. More serious, though less common, side effects include falls, fainting and impaired kidney function. Anderson said these side effects can usually be avoided with careful monitoring of a patient.

But as this study illustrates, there are also benefits with blood pressure-lowering drugs. Anderson said while doctors don’t know exactly how lower blood pressure reduces the risk of stroke, “presumably, it reduces stress on the walls of blood vessels, which lessens the chance of thickening and blockage and rupturing of them.”

Both Kitagawa and Anderson said lifestyle changes — maintaining a healthy weight, eating healthy foods, exercising regularly, reducing stress and reducing salt intake — also play an important role in reducing the risk of a second stroke.

The current study included nearly 1,300 stroke survivors. The study volunteers were recruited from 140 hospitals in Japan. They were enrolled between 2010 and 2016.

The participants were randomly assigned to one of two groups: standard control of pressure to 140/90, or an intensive control group that aimed for 120/80 or lower.

The study was stopped early due to slow enrollment and funding issues.

The baseline blood pressure for both groups was 145/84 mm Hg. During the shortened follow-up period, the standard group’s blood pressure dropped to 133/78 and the intensive group’s was reduced to 127/77.

Ninety-one people had a second stroke. The intensive group appeared to have a lower risk of an additional stroke, but the findings weren’t statistically significant, the study authors said.

However, the researchers pooled their findings with the results of three previous studies on blood pressure reduction and secondary stroke prevention, and found a drop in risk of 22% for intensive control.

“This research reinforces the importance of good blood pressure control in people who have survived a stroke,” Anderson said.

He added that it’s important that people remember to take their blood pressure medications as prescribed. Anderson said many people forget to take them regularly, so he suggested using mobile apps on your phone if you need help remembering to take your medications.

Source: HealthDay

The ‘Bottom’ Blood Pressure Number Matters, Too

Amy Norton wrote . . . . . . . . .

When it comes to blood pressure readings, the “top” number seems to grab all the attention.

But a large, new study confirms that both numbers are, in fact, critical in determining the risk of heart attack and stroke.

Blood pressure measurements are given as a “top” and “bottom” number. The first reflects systolic blood pressure, the amount of pressure in the arteries as the heart contracts. The second reflects diastolic blood pressure, the pressure in the arteries between heart muscle contractions.

For years, systolic blood pressure has been seen as the one that really matters. That’s based on studies — including the famous Framingham Heart Study — showing that high systolic blood pressure is a stronger predictor of heart disease and stroke.

At the same time, though, doctors measure both systolic and diastolic blood pressure, and treatment guidelines are based on both. So just how important is that diastolic number?

“The idea behind this new study was to address the confusion,” said lead researcher Dr. Alexander Flint, an investigator with Kaiser Permanente Northern California’s division of research.

Using medical records from 1.3 million patients, his team confirmed that, yes, high systolic blood pressure was a stronger risk factor for heart attack and stroke. But those risks also climbed in tandem with diastolic pressure; and people with normal systolic readings were still at risk if their diastolic pressure was high.

“There’s been a common belief that systolic blood pressure is the only one that matters,” Flint said. “But diastolic definitely matters.”

He and his colleagues reported the findings in the New England Journal of Medicine.

The definition of high blood pressure has gotten a revamp in recent years. Guidelines issued in 2017 by the American College of Cardiology (ACC) and other heart groups lowered the threshold for diagnosing the condition — from the traditional 140/90 mm Hg to 130/80.

The fact that treatment guidelines include a diastolic pressure threshold implies that it’s important. And indeed it is, said Dr. Karol Watson, a member of the ACC’s prevention section and leadership council.

In fact, she said, doctors once thought that diastolic blood pressure was the more important one — based on research at the time. Then came the studies showing that systolic pressure was generally a better predictor of people’s risk of heart disease and stroke.

In addition, Watson said, high systolic blood pressure is more prevalent, because of natural changes in blood pressure as people age.

“As we get older, systolic blood pressure keeps marching up,” she explained. Diastolic blood pressure, on the other hand, generally peaks when people are in their 40s to 60s — and then it declines.

But it’s clear, Watson said, that while systolic and diastolic blood pressure are different, they both deserve attention.

In the latest study, cardiovascular risks rose with each “unit increase” in systolic pressure above 140, by about 18% on average. Meanwhile, each increase in diastolic blood pressure above 90 was tied to a 6% increase in heart disease and stroke risk.

The researchers saw a similar pattern when they looked at blood pressure increases above the 130/80 threshold. That, Flint said, supports the 2017 guideline shift.

The findings are based on over 1.3 million patients in the Kaiser Permanente health system who had roughly 36.8 million blood pressure readings taken from 2007 through 2016. Over eight years, more than 44,000 patients had a heart attack or stroke.

According to Flint, it’s the largest study of its kind to date.

The bottom line for patients, Watson said, is that they should care about both blood pressure numbers. In her experience, she noted, patients often point to the number that’s in the normal range and say, “But look how good this is.”

Flint agreed, saying that no one should “ignore” the diastolic number. “It’s important not only in blood pressure treatment, but on the side of diagnosis, too,” he said.

Source: HealthDay


Today’s Comic

Blood Pressure Drug Linked with Increased Risk of Bowel Condition

Kate Wighton wrote . . . . . . . . .

A type of blood pressure lowering medication, called a calcium-channel blocker, may be linked with increased risk of bowel condition diverticulosis.

This condition causes small bulges or pouches to appear in the lining of the intestine. Particularly affecting the elderly (as many as 65 per cent of over 85s may be affected), diverticulosis can in some cases can lead to a medical emergency if the pouches become infected or burst.

The new early-stage research finding comes from a team of scientists led by Imperial College London, who investigated the effectiveness and side effects of three common blood pressure medications: ACE-inhibitors, beta-blockers and calcium channel blockers.

High blood pressure affects one in ten adults across the globe, and increases the risk of heart attack and stroke. The most common treatments for high blood pressure are lifestyle changes and medications.

However, despite the three main medications being taken by millions, investigating their potential side effects (as well as studying their effectiveness for treating other diseases), can be difficult and often involves lengthy and expensive clinical trials.

Genetic clues

To overcome this problem, the research team, led by Imperial’s School of Public Health, used genetic analyses to study the effects of the drugs.

By investigating versions of genes that mimic the effects of these drugs, the team were able to study the drugs’ effectiveness – and their potential side effects.

First, the researchers, who published their work in the journal Circulation, identified the proteins targeted by the drugs, and which help lower blood pressure. Next, they analysed genetic data from around 750,000 people and identified the so-called genetic variants that code for these proteins.

The team, who included researchers from LMU Munich, then studied whether these gene variants – which cause increased production of these proteins – were linked to an increased or decreased risk of other diseases.

The good news was that, as expected, these so-called genetic variants (which coded for proteins involved in lowering blood pressure) were linked to lower heart disease and stroke risk.

Increased risk

However after assessing the risk of around 900 different diseases – using data from the UK Biobank study – the team found that the versions of genes related to the effects of a particular type of calcium channel blocker – the non-dihydropyridine class, were linked to an increased the risk of a bowel condition called diverticulosis.

The team compared their findings with further genetic data, and supported the potential link with an increased risk of the bowel condition.

The link now needs further investigation with larger trials, explains Dr Dipender Gill, co-lead author of the research from Imperial’s School of Public Health: “This is the first time that this class of blood pressure drug has been associated with diverticulosis. We’re not sure of the underlying mechanism – although it may relate to effects on the function of intestine muscles, which perform contractions to transport food through the gut.”

Dr Joanna Tzoulaki, senior author from Imperial’s School of Public Health added: “The study of genetic variants that mimic the effect of drugs is evolving as a powerful concept to help prioritise clinical trials and design clinical trials more likely to be successful”.

Dr Gill cautions the findings should not change current prescribing guidelines and that people should not stop taking their medication unless first consulting their doctor.

He added: “These findings should not change clinical practice, but instead should act as a catalyst for further research.”

Source: Imperial College London