High blood prere: When is blood prere too high??High blood prere is diagnosed later in Europe than in the USA. This causes discussion. For patients, however, it is not only a question of when treatment is given, but also how it is given.
It has the reputation of being a silent killer: Often unnoticed for years, high blood prere damages the heart, blood vessels, brain and kidneys. More than 20 million people in Germany have high blood prere. Many of them are completely unaware of their disease. While some sufferers experience non-specific symptoms such as dizziness, ringing in the ears, or nosebleeds. But in the vast majority of cases, high blood prere causes hidden damage to blood vessels and organs. The body gets used to the new preres and compensates for them until it can no longer do so. Then the damage is already done.
To avoid the long-term consequences of too high blood prere, it must be brought into a normal range, for example with medication. However, heart experts disagree on this point: When is blood prere still normal, and when is it actually too high?? The answer to this question determines how many people will be diagnosed with high blood prere – and whether they will need treatment.
This article is contained in Spektrum Gesundheit, Therapy in time with the inner clock
Basically, the measured blood prere consists of an upper, the systolic value, and a lower, the diastolic blood prere value. The ideal blood prere for adults is below 120 to 80 millimeters of mercury (120/80 mm Hg); it should not be lower than 90/60 mm Hg. One mm Hg corresponds to the prere exerted by a column of mercury one millimeter high. The unit of measurement dates back to a time when blood prere was measured using a mercury-containing gauge.
Still normal in Europe, already too high in the USA
In Germany and Europe, doctors currently diagnose high blood prere when the systolic blood prere is 140 mm Hg or higher and the diastolic blood prere is 90 mm Hg or higher. The same has long been true in the USA. Until two U.S. professional societies, the American College of Cardiology and the American Heart Association, changed the levels to 130/80 mm Hg in 2017. Because of the new definition, suddenly one in three residents of the United States was considered to have high blood prere – previously it was not even one in four.
The impetus for the correction of the U.S. guidelines came from the Sprint study, which was published back in 2015. According to this study, people who have an increased risk of cardiovascular disease are less likely to die earlier if their systolic blood prere can be lowered to 120 mm Hg. The data from the study are controversial, however, because blood prere was measured differently for these studies than is usual in everyday medical practice.
How does our body maintain blood prere?
To reliably supply all organs with oxygen and nutrients, blood must be pumped through the body with a certain force. Responsible for this are the heart, blood vessels and muscles. The heart sets the starting tempo: By contracting vigorously, it forces blood out of its left main chamber into the aorta. At rest, the heart pumps four to five liters per minute through the vessels of an adult. This show of strength is reflected in the upper, systolic blood prere value. Before it tenses up the next time, the heart goes slack for a short time. The blood prere drops slightly. The relaxation phase becomes visible in the lower, diastolic blood prere value. Both values together give the blood prere of a person.
Blood prere is by no means static. In the course of a day it varies constantly. It is usually somewhat higher in the morning than at night. In addition, factors such as sport, anger and stress influence the heart's pumping capacity and thus blood prere.
However, the heart is not solely responsible for maintaining blood prere: As it travels through the body, the blood loses more and more prere. Once it has reached the feet, the energy with which it was sent out by the heart is no longer sufficient to transport the blood back – especially since gravity also works against it. Here, vessels and especially muscles help by contracting and pumping up the blood in this way. Well-trained calf muscles then become the leg veins' best friend.
The European Society of Cardiology considers values of 130/80 mm Hg to be "high normal blood prere" and therefore not in need of treatment. It generally recommends lowering blood prere to below 140/90 mm Hg. For 70-year-olds with an increased cardiovascular risk, target values of below 130/80 mm Hg apply. To achieve these goals, doctors work with two factors: the patient's lifestyle and medications. Because changing habits is often tedious, more than a few patients prefer to take tablets. Particularly since the medicines are gladly prescribed by physicians. Almost all antihypertensive drugs are off-patent, which means they are inexpensive. And effective.
Nevertheless, it is important for physicians to look carefully when prescribing medication for high blood prere. These are particularly useful when blood prere is permanently above 140/90 mm Hg. "Here, studies have shown that the active substances can help very well to reduce the risk of stroke, cardiac muscle weakness, kidney disease or heart attack," says Heribert Schunkert, Director of the Clinic for Cardiovascular Diseases at the German Heart Center in Munich and Vice Chairman of the Board of the German Heart Foundation.
The closer the blood prere is to normal values, the lower the effects of the medication. Schunkert says that it becomes exciting when the blood prere is just below a value of 140 mm Hg without medication. Different studies would come to different results here, but on the whole it looks as if the start of a medicinal blood prere reduction in this area no longer brings much. If there is a need for therapy, systolic blood prere should ideally be lowered to the 120 to 130 mm Hg range. "Below that, you buy a relatively small benefit with sometimes burdensome side effects," says Schunkert. "In many patients, this is simply not necessary."
What are the benefits of lower thresholds??
If lower limits made people more likely to think about their blood prere, they would have served their purpose, says cardiologist Franz-Josef Neumann. "The question is: At what point do you start to correct it??"Neumann is medical director of the Clinic for Cardiology and Angiology II in Bad Krozingen. "The Americans decided then that they would start earlier than before. This lowers the threshold for patients to seek advice," explains the physician. However, this does not automatically mean that the patient should be given medication. "First and foremost, it will advise what impact a healthy lifestyle has on hypertension."
In Germany, blood prere control is still poor despite all the progress made in recent years. About one-fifth of hypertension patients are unaware of their condition, Neumann says. And of those who are treated, a third do not even reach traditional targets because treatment is not consistent enough. "In the end, only about half of hypertension patients are well controlled."
"We have found depressive mood states in about half of those patients who took medication for hypertension" (Seryan Atasoy, epidemiologist at Helmholtz Zentrum Munchen)
A team from Helmholtz Zentrum Munchen and Technische Universitat Munchen has investigated whether lower threshold values for high blood prere actually save lives. For this purpose, the data of about 12,000 patients were evaluated. In the study published in the European Heart Journal at the end of 2018, scientists concluded that lower limits do not provide better protection against fatal heart disease. Of particular interest: they questioned the often-claimed positive effect on patient motivation.
The results of the study even suggest that earlier blood prere therapy with medication can have negative consequences. "We found depressive mood states in about half of those patients who took medication for hypertension," says Seryan Atasoy, epidemiologist at Helmholtz Zentrum Munchen and lead author of the study. By comparison, only a good third of untreated patients suffer from depressive moods. "We think this is a kind of labeling effect," Atasoy explains. "When you declare people sick, it affects their mental health. They may not have previously considered themselves to be ill and may not have felt that way."Depression in turn increases the risk of potentially fatal cardiovascular diseases.
Atasoy therefore advocates using limits for guidance at best. "Instead, individual factors should determine whether or not to treat blood prere with medication: what other risks does the patient bring to the table? Smokes he? Are there other concomitant diseases?", says the doctor.
Doctors and patients should show more commitment
In some cases, neither a healthy lifestyle nor medication can lower hypertension. Often such resistant high values are related to the kidney. On the one hand, certain kidney diseases such as a narrowing of the renal arteries, a reduced kidney size or cystic kidneys can lead to high blood prere. Damage to the organ causes more blood prere-raising hormones to be released. On the other hand, high blood prere damages the kidneys: Their fine vessels become inflamed and constricted. So that the kidneys continue to be sufficiently supplied with blood, the body must increase the blood prere.
To break this cycle, surgery is performed in cases of particularly severe high blood prere: Doctors insert a tube through the inguinal artery, which they use to sclerotize the nerve fibers in the renal arteries and thus switch them off. The procedure is called renal denervation. "In the process, we obliterate the nerve fibers with three drops of 96-percent ethanol, i.e., pure alcohol," says Elias Noory, who heads the catheter laboratory for peripheral interventions, interventional hypertensiology and the hypertension outpatient clinic at Freiburg University Hospital. Three fine needles prick the artery wall and release the alcohol. As a result, nerve impulses no longer arrive at the veins, which cause vasoconstriction. According to Noory, this brings about an average reduction in blood prere of 18 mm Hg. He recommends the procedure for patients whose blood prere is higher than 140/90 mm Hg despite taking at least two blood prere-lowering medications.
"Lowering blood prere is a team effort. We doctors shouldn't make it quite so easy for our patients" (Heribert Schunkert, Director of the Clinic for Cardiovascular Diseases at the German Heart Center in Munich)
Although people with a predisposition or kidney disease rely on medication or medical interventions to lower their blood prere, they may not be able to do so. The mass, stresses cardiologist Schunkert, is not that however. The vast majority of hypertensive patients can control their own blood prere. "Little salt, a lot of exercise, eating a healthy diet overall and getting rid of excess weight – all this generally does no harm to anyone and usually shows clear effects in hypertension patients," says Schunkert. As rough guideline applies: For each lost kilo the blood prere sinks around one mm Hg.
For a radical change many concerning however often the motivation is missing. Schunkert would like to see a bit more ambition in the cooperation between patient and doctor: "Lowering blood prere is teamwork. We doctors should not make it quite so easy for our patients."Instead of debates about whether to prescribe pills at 130 or 140 mm Hg, more energy could be spent on educating patients about the possibilities that lie in lifestyle changes.