Hypertension | |
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Other names | Arterial hypertension, high blood pressure |
Automated arm blood pressure meter showing arterial hypertension (shown by a systolic blood pressure 158 mmHg, diastolic blood pressure 99 mmHg and heart rate of 80 beats per minute) | |
Specialty | Cardiology, Nephrology |
Symptoms | None [1] |
Complications | Coronary artery disease, stroke, heart failure, peripheral arterial disease, vision loss, chronic kidney disease, dementia [2] [3] [4] |
Causes | Usually lifestyle and genetic factors [5] [6] |
Risk factors | Lack of sleep, excess salt, excess body weight, smoking, alcohol, [1] [5] air pollution [7] |
Diagnostic method | Resting blood pressure 130/80 or 140/90 mmHg [5] [8] |
Treatment | Lifestyle changes, medications [9] |
Frequency | 16–37% globally [5] |
Deaths | 9.4 million / 18% (2010) [10] |
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Hypertension, also known as high blood pressure, is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. [11] High blood pressure usually does not cause symptoms itself. [1] It is, however, a major risk factor for stroke, coronary artery disease, heart failure, atrial fibrillation, peripheral arterial disease, vision loss, chronic kidney disease, and dementia. [2] [3] [4] [12] Hypertension is a major cause of premature death worldwide. [13]
High blood pressure is classified as primary (essential) hypertension or secondary hypertension. [5] About 90–95% of cases are primary, defined as high blood pressure due to nonspecific lifestyle and genetic factors. [5] [6] Lifestyle factors that increase the risk include excess salt in the diet, excess body weight, smoking, physical inactivity and alcohol use. [1] [5] The remaining 5–10% of cases are categorized as secondary high blood pressure, defined as high blood pressure due to a clearly identifiable cause, such as chronic kidney disease, narrowing of the kidney arteries, an endocrine disorder, or the use of birth control pills. [5]
Blood pressure is classified by two measurements, the systolic (high reading) and diastolic (lower reading) pressures. [1] For most adults, normal blood pressure at rest is within the range of 100–130 millimeters mercury (mmHg) systolic and 60–80 mmHg diastolic. [8] [14] For most adults, high blood pressure is present if the resting blood pressure is persistently at or above 130/80 or 140/90 mmHg. [5] [8] Different numbers apply to children. [15] Ambulatory blood pressure monitoring over a 24-hour period appears more accurate than office-based blood pressure measurement. [5] [11] Hypertension is around twice as common in diabetics. [16]
Lifestyle changes and medications can lower blood pressure and decrease the risk of health complications. [9] Lifestyle changes include weight loss, physical exercise, decreased salt intake, reducing alcohol intake, and a healthy diet. [5] If lifestyle changes are not sufficient, then blood pressure medications are used. [9] Up to three medications taken concurrently can control blood pressure in 90% of people. [5] The treatment of moderately high arterial blood pressure (defined as >160/100 mmHg) with medications is associated with an improved life expectancy. [17] The effect of treatment of blood pressure between 130/80 mmHg and 160/100 mmHg is less clear, with some reviews finding benefit [8] [18] [19] and others finding unclear benefit. [20] [21] [22] High blood pressure affects between 16 and 37% of the population globally. [5] In 2010 hypertension was believed to have been a factor in 17.8% of all deaths (9.4 million globally). [10]
Hypertension is rarely accompanied by symptoms, and its identification is usually through health screening, or when seeking healthcare for an unrelated problem. Some people with high blood pressure report headaches (particularly at the back of the head and in the morning), as well as lightheadedness, vertigo, tinnitus (buzzing or hissing in the ears), altered vision or fainting episodes. [23] These symptoms, however, might be related to associated anxiety rather than the high blood pressure itself. [24]
On physical examination, hypertension may be associated with the presence of changes in the optic fundus seen by ophthalmoscopy. [25] The severity of the changes typical of hypertensive retinopathy is graded from I to IV; grades I and II may be difficult to differentiate. [25] The severity of the retinopathy correlates roughly with the duration or the severity of the hypertension. [23]
Secondary hypertension is hypertension due to an identifiable cause, and may result in certain specific additional signs and symptoms. For example, as well as causing high blood pressure, Cushing's syndrome frequently causes truncal obesity, [26] glucose intolerance, moon face, a hump of fat behind the neck and shoulders (referred to as a buffalo hump), and purple abdominal stretch marks. [27] Hyperthyroidism frequently causes weight loss with increased appetite, fast heart rate, bulging eyes, and tremor. Renal artery stenosis (RAS) may be associated with a localized abdominal bruit to the left or right of the midline (unilateral RAS), or in both locations (bilateral RAS). Coarctation of the aorta frequently causes a decreased blood pressure in the lower extremities relative to the arms, or delayed or absent femoral arterial pulses. Pheochromocytoma may cause abrupt episodes of hypertension accompanied by headache, palpitations, pale appearance, and excessive sweating. [27]
Severely elevated blood pressure (equal to or greater than a systolic 180 mmHg or diastolic of 120 mmHg) is referred to as a hypertensive crisis. [28] Hypertensive crisis is categorized as either hypertensive urgency or hypertensive emergency, according to the absence or presence of end organ damage, respectively. [29] [30]
In hypertensive urgency, there is no evidence of end organ damage resulting from the elevated blood pressure. In these cases, oral medications are used to lower the BP gradually over 24 to 48 hours. [31]
In hypertensive emergency, there is evidence of direct damage to one or more organs. [32] [33] The most affected organs include the brain, kidney, heart and lungs, producing symptoms which may include confusion, drowsiness, chest pain and breathlessness. [31] In hypertensive emergency, the blood pressure must be reduced more rapidly to stop ongoing organ damage; [31] however, there is a lack of randomized controlled trial evidence for this approach. [33]
Hypertension occurs in approximately 8–10% of pregnancies. [27] Two blood pressure measurements six hours apart of greater than 140/90 mmHg are diagnostic of hypertension in pregnancy. [34] High blood pressure in pregnancy can be classified as pre-existing hypertension, gestational hypertension, or pre-eclampsia. [35] Women who have chronic hypertension before their pregnancy are at increased risk of complications such as premature birth, low birthweight or stillbirth. [36] Women who have high blood pressure and had complications in their pregnancy have three times the risk of developing cardiovascular disease compared to women with normal blood pressure who had no complications in pregnancy. [37] [38]
Pre-eclampsia is a serious condition of the second half of pregnancy and following delivery characterised by increased blood pressure and the presence of protein in the urine. [27] It occurs in about 5% of pregnancies and is responsible for approximately 16% of all maternal deaths globally. [27] Pre-eclampsia also doubles the risk of death of the baby around the time of birth. [27] Usually there are no symptoms in pre-eclampsia and it is detected by routine screening. When symptoms of pre-eclampsia occur the most common are headache, visual disturbance (often "flashing lights"), vomiting, pain over the stomach, and swelling. Pre-eclampsia can occasionally progress to a life-threatening condition called eclampsia, which is a hypertensive emergency and has several serious complications including vision loss, brain swelling, seizures, kidney failure, pulmonary edema, and disseminated intravascular coagulation (a blood clotting disorder). [27] [39]
In contrast, gestational hypertension is defined as new-onset hypertension during pregnancy without protein in the urine. [35]
Failure to thrive, seizures, irritability, lack of energy, and difficulty in breathing [40] can be associated with hypertension in newborns and young infants. In older infants and children, hypertension can cause headache, unexplained irritability, fatigue, failure to thrive, blurred vision, nosebleeds, and facial paralysis. [40] [41]
Hypertension results from a complex interaction of genes and environmental factors. Numerous common genetic variants with small effects on blood pressure have been identified [42] as well as some rare genetic variants with large effects on blood pressure. [43] Also, genome-wide association studies (GWAS) have identified 35 genetic loci related to blood pressure; 12 of these genetic loci influencing blood pressure were newly found. [44] Sentinel SNP for each new genetic locus identified has shown an association with DNA methylation at multiple nearby CpG sites. These sentinel SNP are located within genes related to vascular smooth muscle and renal function. DNA methylation might affect in some way linking common genetic variation to multiple phenotypes even though mechanisms underlying these associations are not understood. Single variant test performed in this study for the 35 sentinel SNP (known and new) showed that genetic variants singly or in aggregate contribute to risk of clinical phenotypes related to high blood pressure. [44]
Coronary artery ectasia: Coronary artery ectasia (CAE) is characterized by the enlargement of a coronary artery to 1.5 times or more than other non-ectasia parts of the vessel. The pooled unadjusted OR of CAE in subjects with Hypertension (HTN) in comparison by subjects without HTN was estimated 1.44. [45]
Blood pressure rises with aging when associated with a western diet and lifestyle and the risk of becoming hypertensive in later life is significant. [46] [47] Several environmental factors influence blood pressure. High salt intake raises the blood pressure in salt sensitive individuals; lack of exercise and central obesity can play a role in individual cases. The possible roles of other factors such as caffeine consumption, [48] and vitamin D deficiency [49] are less clear. Insulin resistance, which is common in obesity and is a component of syndrome X (or the metabolic syndrome), also contributes to hypertension. [50]
Events in early life, such as low birth weight, maternal smoking, and lack of breastfeeding may be risk factors for adult essential hypertension, although the mechanisms linking these exposures to adult hypertension remain unclear. [51] An increased rate of high blood uric acid has been found in untreated people with hypertension in comparison with people with normal blood pressure, although it is uncertain whether the former plays a causal role or is subsidiary to poor kidney function. [52] Average blood pressure may be higher in the winter than in the summer. [53] Periodontal disease is also associated with high blood pressure. [54]
Secondary hypertension results from an identifiable cause. Kidney disease is the most common secondary cause of hypertension. [27] Hypertension can also be caused by endocrine conditions, such as Cushing's syndrome, hyperthyroidism, hypothyroidism, acromegaly, Conn's syndrome or hyperaldosteronism, renal artery stenosis (from atherosclerosis or fibromuscular dysplasia), hyperparathyroidism, and pheochromocytoma. [27] [55] Other causes of secondary hypertension include obesity, sleep apnea, pregnancy, coarctation of the aorta, excessive eating of liquorice, excessive drinking of alcohol, certain prescription medicines, herbal remedies, and stimulants such as coffee, cocaine and methamphetamine. [27] [56] Arsenic exposure through drinking water has been shown to correlate with elevated blood pressure. [57] [58] Depression was also linked to hypertension. [59] Loneliness is also a risk factor. [60]
A 2018 review found that any alcohol increased blood pressure in males while over one or two drinks increased the risk in females. [61]
In most people with established essential hypertension, increased resistance to blood flow (total peripheral resistance) accounts for the high pressure while cardiac output remains normal. [62] There is evidence that some younger people with prehypertension or 'borderline hypertension' have high cardiac output, an elevated heart rate and normal peripheral resistance, termed hyperkinetic borderline hypertension. [63] These individuals develop the typical features of established essential hypertension in later life as their cardiac output falls and peripheral resistance rises with age. [63] Whether this pattern is typical of all people who ultimately develop hypertension is disputed. [64] The increased peripheral resistance in established hypertension is mainly attributable to structural narrowing of small arteries and arterioles, [65] although a reduction in the number or density of capillaries may also contribute. [66]
It is not clear whether or not vasoconstriction of arteriolar blood vessels plays a role in hypertension. [67] Hypertension is also associated with decreased peripheral venous compliance, [68] which may increase venous return, increase cardiac preload and, ultimately, cause diastolic dysfunction.
Pulse pressure (the difference between systolic and diastolic blood pressure) is frequently increased in older people with hypertension. [69] This can mean that systolic pressure is abnormally high, but diastolic pressure may be normal or low, a condition termed isolated systolic hypertension. [70] The high pulse pressure in elderly people with hypertension or isolated systolic hypertension is explained by increased arterial stiffness, which typically accompanies aging and may be exacerbated by high blood pressure. [71]
Many mechanisms have been proposed to account for the rise in peripheral resistance in hypertension. Most evidence implicates either disturbances in the kidneys' salt and water handling (particularly abnormalities in the intrarenal renin–angiotensin system) [72] or abnormalities of the sympathetic nervous system. [73] These mechanisms are not mutually exclusive and it is likely that both contribute to some extent in most cases of essential hypertension. It has also been suggested that endothelial dysfunction and vascular inflammation may also contribute to increased peripheral resistance and vascular damage in hypertension. [74] [75] Interleukin 17 has garnered interest for its role in increasing the production of several other immune system chemical signals thought to be involved in hypertension such as tumor necrosis factor alpha, interleukin 1, interleukin 6, and interleukin 8. [76]
Excessive sodium or insufficient potassium in the diet leads to excessive intracellular sodium, which contracts vascular smooth muscle, restricting blood flow and so increases blood pressure. [77] [78]
Hypertension is diagnosed on the basis of a persistently high resting blood pressure. The American Heart Association (AHA) recommends at least three resting measurements on at least two separate health care visits. [79]
In Britain, 'Blood Pressure UK' states that a healthy blood pressure is any reading between 90/60 mmHg and 120/80 mmHg. [80]
For an accurate diagnosis of hypertension to be made, it is essential for proper blood pressure measurement technique to be used. [81] Improper measurement of blood pressure is common and can change the blood pressure reading by up to 10 mmHg, which can lead to misdiagnosis and misclassification of hypertension. [81] Correct blood pressure measurement technique involves several steps. Proper blood pressure measurement requires the person whose blood pressure is being measured to sit quietly for at least five minutes which is then followed by application of a properly fitted blood pressure cuff to a bare upper arm. [81] The person should be seated with their back supported, feet flat on the floor, and with their legs uncrossed. [81] The person whose blood pressure is being measured should avoid talking or moving during this process. [81] The arm being measured should be supported on a flat surface at the level of the heart. [81] Blood pressure measurement should be done in a quiet room so the medical professional checking the blood pressure can hear the Korotkoff sounds while listening to the brachial artery with a stethoscope for accurate blood pressure measurements. [81] [82] The blood pressure cuff should be deflated slowly (2–3 mmHg per second) while listening for the Korotkoff sounds. [82] The bladder should be emptied before a person's blood pressure is measured since this can increase blood pressure by up to 15/10 mmHg. [81] Multiple blood pressure readings (at least two) spaced 1–2 minutes apart should be obtained to ensure accuracy. [82] Ambulatory blood pressure monitoring over 12 to 24 hours is the most accurate method to confirm the diagnosis. [83] An exception to this is those with very high blood pressure readings especially when there is poor organ function. [84]
With the availability of 24-hour ambulatory blood pressure monitors and home blood pressure machines, the importance of not wrongly diagnosing those who have white coat hypertension has led to a change in protocols. In the United Kingdom, current best practice is to follow up a single raised clinic reading with ambulatory measurement, or less ideally with home blood pressure monitoring over the course of 7 days. [84] The United States Preventive Services Task Force also recommends getting measurements outside of the healthcare environment. [83] Pseudohypertension in the elderly or noncompressibility artery syndrome may also require consideration. This condition is believed to be due to calcification of the arteries resulting in abnormally high blood pressure readings with a blood pressure cuff while intra arterial measurements of blood pressure are normal. [85] Orthostatic hypertension is when blood pressure increases upon standing. [86]
System | Tests |
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Kidney | Microscopic urinalysis, protein in the urine, BUN, creatinine |
Endocrine | Serum sodium, potassium, calcium, TSH |
Metabolic | Fasting blood glucose, HDL, LDL, total cholesterol, triglycerides |
Other | Hematocrit, electrocardiogram, chest radiograph |
Once the diagnosis of hypertension has been made, healthcare providers should attempt to identify the underlying cause based on risk factors and other symptoms, if present. Secondary hypertension is more common in preadolescent children, with most cases caused by kidney disease. Primary or essential hypertension is more common in adolescents and adults and has multiple risk factors, including obesity and a family history of hypertension. [93] Laboratory tests can also be performed to identify possible causes of secondary hypertension, and to determine whether hypertension has caused damage to the heart, eyes, and kidneys. Additional tests for diabetes and high cholesterol levels are usually performed because these conditions are additional risk factors for the development of heart disease and may require treatment. [6]
Initial assessment of the hypertensive people should include a complete history and physical examination. Serum creatinine is measured to assess for the presence of kidney disease, which can be either the cause or the result of hypertension. Serum creatinine alone may overestimate glomerular filtration rate and the 2003 JNC7 guidelines advocate the use of predictive equations such as the Modification of Diet in Renal Disease (MDRD) formula to estimate glomerular filtration rate (eGFR). [32] eGFR can also provide a baseline measurement of kidney function that can be used to monitor for side effects of certain anti-hypertensive drugs on kidney function. Additionally, testing of urine samples for protein is used as a secondary indicator of kidney disease. Electrocardiogram (EKG/ECG) testing is done to check for evidence that the heart is under strain from high blood pressure. It may also show whether there is thickening of the heart muscle (left ventricular hypertrophy) or whether the heart has experienced a prior minor disturbance such as a silent heart attack. A chest X-ray or an echocardiogram may also be performed to look for signs of heart enlargement or damage to the heart. [27]
Categories | Systolic blood pressure, mmHg | And/or | Diastolic blood pressure, mmHg | ||
---|---|---|---|---|---|
Method | Office | 24h ambulatory | Office | 24h ambulatory | |
Hypotension [94] | <110 | <100 | or | <70 | <60 |
American College of Cardiology/American Heart Association (2017) [95] | |||||
Normal | <120 | <115 | and | <80 | <75 |
Elevated | 120–129 | 115–124 | and | <80 | <75 |
Hypertension, stage 1 | 130–139 | 125–129 | or | 80–89 | 75–79 |
Hypertension, stage 2 | ≥140 | ≥130 | or | ≥90 | ≥80 |
European Society of Hypertension (2023) [96] | |||||
Optimal | <120 | — | and | <80 | — |
Normal | 120–129 | — | and/or | 80–84 | — |
High normal | 130–139 | — | and/or | 85–89 | — |
Hypertension, grade 1 | 140–159 | ≥130 | and/or | 90–99 | ≥80 |
Hypertension, grade 2 | 160–179 | — | and/or | 100–109 | — |
Hypertension, grade 3 | ≥180 | — | and/or | ≥110 | — |
In people aged 18 years or older, hypertension is defined as either a systolic or a diastolic blood pressure measurement consistently higher than an accepted normal value (this is above 129 or 139 mmHg systolic, 89 mmHg diastolic depending on the guideline). [5] [8] Lower thresholds are used if measurements are derived from 24-hour ambulatory or home monitoring. [95]
Hypertension occurs in around 0.2 to 3% of newborns; however, blood pressure is not measured routinely in healthy newborns. [41] Hypertension is more common in high risk newborns. A variety of factors, such as gestational age, postconceptional age and birth weight needs to be taken into account when deciding if a blood pressure is normal in a newborn. [41]
Hypertension defined as elevated blood pressure over several visits affects 1% to 5% of children and adolescents and is associated with long-term risks of ill-health. [97] Blood pressure rises with age in childhood and, in children, hypertension is defined as an average systolic or diastolic blood pressure on three or more occasions equal or higher than the 95th percentile appropriate for the sex, age and height of the child. High blood pressure must be confirmed on repeated visits however before characterizing a child as having hypertension. [97] Prehypertension in children has been defined as average systolic or diastolic blood pressure that is greater than or equal to the 90th percentile, but less than the 95th percentile. [97] In adolescents, it has been proposed that hypertension and pre-hypertension are diagnosed and classified using the same criteria as in adults. [97]
High blood pressure is frequently encountered in pediatric emergency and outpatient clinics, one of the simplest and reliable methods to assess the need for referral and or further action is the score developed by Elbaba M., published in 2018. [98] The score is composed of a set of 10 items with grades 1, 2 or 3 for each item. The author assumed the mid score of 15 or less is not associated with true hypertension, it can be reactive, white-coat or unreliable measurement. And the score of 16 or above reflects a warning alarm to true hypertension that usually require monitoring, investigations and or treatment.
Much of the disease burden of high blood pressure is experienced by people who are not labeled as hypertensive. [99] Consequently, population strategies are required to reduce the consequences of high blood pressure and reduce the need for antihypertensive medications. Lifestyle changes are recommended to lower blood pressure, before starting medications. The 2004 British Hypertension Society guidelines [100] proposed lifestyle changes consistent with those outlined by the US National High BP Education Program in 2002 [101] for the primary prevention of hypertension:
Avoiding or learning to manage stress can help a person control blood pressure.
A few relaxation techniques that can help relieve stress are:
Effective lifestyle modification may lower blood pressure as much as an individual antihypertensive medication. Combinations of two or more lifestyle modifications can achieve even better results. [99] There is considerable evidence that reducing dietary salt intake lowers blood pressure, but whether this translates into a reduction in mortality and cardiovascular disease remains uncertain. [103] Estimated sodium intake ≥6 g/day and <3 g/day are both associated with high risk of death or major cardiovascular disease, but the association between high sodium intake and adverse outcomes is only observed in people with hypertension. [104] Consequently, in the absence of results from randomized controlled trials, the wisdom of reducing levels of dietary salt intake below 3 g/day has been questioned. [103] ESC guidelines mention periodontitis is associated with poor cardiovascular health status. [105]
The value of routine screening for hypertension is debated. [106] [107] [108] In 2004, the National High Blood Pressure Education Program recommended that children aged 3 years and older have blood pressure measurement at least once at every health care visit [97] and the National Heart, Lung, and Blood Institute and American Academy of Pediatrics made a similar recommendation. [109] However, the American Academy of Family Physicians [110] supports the view of the U.S. Preventive Services Task Force that the available evidence is insufficient to determine the balance of benefits and harms of screening for hypertension in children and adolescents who do not have symptoms. [111] [112] The US Preventive Services Task Force recommends screening adults 18 years or older for hypertension with office blood pressure measurement. [108] [113]
According to one review published in 2003, reduction of the blood pressure by 5 mmHg can decrease the risk of stroke by 34%, of ischemic heart disease by 21%, and reduce the likelihood of dementia, heart failure, and mortality from cardiovascular disease. [114]
Various expert groups have produced guidelines regarding how low the blood pressure target should be when a person is treated for hypertension. These groups recommend a target below the range 140–160 / 90–100 mmHg for the general population. [14] [15] [115] [116] Cochrane reviews recommend similar targets for subgroups such as people with diabetes [117] and people with prior cardiovascular disease. [118] Additionally, Cochrane reviews have found that for older individuals with moderate to high cardiovascular risk, the benefits of trying to achieve a lower than standard blood pressure target (at or below 140/90 mmHg) are outweighed by the risk associated with the intervention. [119] These findings may not be applicable to other populations. [119]
Many expert groups recommend a slightly higher target of 150/90 mmHg for those over somewhere between 60 and 80 years of age. [14] [115] [116] [120] The JNC-8 and American College of Physicians recommend the target of 150/90 mmHg for those over 60 years of age, [15] [121] but some experts within these groups disagree with this recommendation. [122] Some expert groups have also recommended slightly lower targets in those with diabetes [14] or chronic kidney disease with protein loss in the urine, [123] but others recommend the same target as for the general population. [15] [117] The issue of what is the best target and whether targets should differ for high risk individuals is unresolved, [124] although some experts propose more intensive blood pressure lowering than advocated in some guidelines. [125]
For people who have never experienced cardiovascular disease who are at a 10-year risk of cardiovascular disease of less than 10%, the 2017 American Heart Association guidelines recommend medications if the systolic blood pressure is >140 mmHg or if the diastolic BP is >90 mmHg. [8] For people who have experienced cardiovascular disease or those who are at a 10-year risk of cardiovascular disease of greater than 10%, it recommends medications if the systolic blood pressure is >130 mmHg or if the diastolic BP is >80 mmHg. [8]
The first line of treatment for hypertension is lifestyle changes, including dietary changes, physical activity, and weight loss. Though these have all been recommended in scientific advisories, [126] a Cochrane systematic review found no evidence (due to lack of data) for effects of weight loss diets on death, long-term complications or adverse events in persons with hypertension. [127] The review did find a decrease in body weight and blood pressure. [127] Their potential effectiveness is similar to and at times exceeds a single medication. [14] If hypertension is high enough to justify immediate use of medications, lifestyle changes are still recommended in conjunction with medication.
Dietary changes shown to reduce blood pressure include diets with low sodium, [128] [129] the DASH diet (Dietary Approaches to Stop Hypertension), [130] which was the best against 11 other diet in an umbrella review, [131] and plant-based diets. [132] There is some evidence green tea consumption may help lower blood pressure, but this is insufficient for it to be recommended as a treatment. [133] There is evidence from randomized, double-blind, placebo-controlled clinical trials that Hibiscus tea consumption significantly reduces systolic blood pressure (-4.71 mmHg, 95% CI [-7.87, -1.55]) and diastolic blood pressure (−4.08 mmHg, 95% CI [-6.48, −1.67]). [134] [135] Beetroot juice consumption also significantly lowers the blood pressure of people with high blood pressure. [136] [137] [138]
Increasing dietary potassium has a potential benefit for lowering the risk of hypertension. [139] [140] The 2015 Dietary Guidelines Advisory Committee (DGAC) stated that potassium is one of the shortfall nutrients which is under-consumed in the United States. [141] However, people who take certain antihypertensive medications (such as ACE-inhibitors or ARBs) should not take potassium supplements or potassium-enriched salts due to the risk of high levels of potassium. [142]
Physical exercise regimens which are shown to reduce blood pressure include isometric resistance exercise, aerobic exercise, resistance exercise, and device-guided breathing. [143]
Stress reduction techniques such as biofeedback or transcendental meditation may be considered as an add-on to other treatments to reduce hypertension, but do not have evidence for preventing cardiovascular disease on their own. [143] [144] [145] Self-monitoring and appointment reminders might support the use of other strategies to improve blood pressure control, but need further evaluation. [146]
Several classes of medications, collectively referred to as antihypertensive medications, are available for treating hypertension.
First-line medications for hypertension include thiazide-diuretics, calcium channel blockers, angiotensin converting enzyme inhibitors (ACE inhibitors), and angiotensin receptor blockers (ARBs). [147] [15] These medications may be used alone or in combination (ACE inhibitors and ARBs are not recommended for use together); the latter option may serve to minimize counter-regulatory mechanisms that act to restore blood pressure values to pre-treatment levels, [15] [148] although the evidence for first-line combination therapy is not strong enough. [149] Most people require more than one medication to control their hypertension. [126] Medications for blood pressure control should be implemented by a stepped care approach when target levels are not reached. [146] Withdrawal of such medications in the elderly can be considered by healthcare professionals, because there is no strong evidence of an effect on mortality, myocardial infarction, or stroke. [150]
Previously, beta-blockers such as atenolol were thought to have similar beneficial effects when used as first-line therapy for hypertension. However, a Cochrane review that included 13 trials found that the effects of beta-blockers are inferior to that of other antihypertensive medications in preventing cardiovascular disease. [151]
The prescription of antihypertensive medication for children with hypertension has limited evidence. There is limited evidence which compare it with placebo and shows modest effect to blood pressure in short term. Administration of higher dose did not make the reduction of blood pressure greater. [152]
Resistant hypertension is defined as high blood pressure that remains above a target level, in spite of being prescribed three or more antihypertensive drugs simultaneously with different mechanisms of action. [153] Failing to take prescribed medications as directed is an important cause of resistant hypertension. [154] Resistant hypertension may also result from chronically high activity of the autonomic nervous system, an effect known as neurogenic hypertension. [155] Electrical therapies that stimulate the baroreflex are being studied as an option for lowering blood pressure in people in this situation. [156]
Some common secondary causes of resistant hypertension include obstructive sleep apnea, pheochromocytoma, renal artery stenosis, coarctation of the aorta, and primary aldosteronism. [157] As many as one in five people with resistant hypertension have primary aldosteronism, which is a treatable and sometimes curable condition. [158]
Refractory hypertension is characterized by uncontrolled elevated blood pressure unmitigated by five or more antihypertensive agents of different classes, including a long-acting thiazide-like diuretic, a calcium channel blocker, and a blocker of the renin-angiotensin system. [159] People with refractory hypertension typically have increased sympathetic nervous system activity, and are at high risk for more severe cardiovascular diseases and all-cause mortality. [159] [160]
Non-modulating essential hypertension is a form of salt-sensitive hypertension, where sodium intake does not modulate either adrenal or renal vascular responses to angiotensin II. Individuals with this subset have been termed non-modulators. [161] They make up 25–30% of the hypertensive population. [162]
no data <110 110–220 220–330 330–440 440–550 550–660 | 660–770 770–880 880–990 990–1100 1100–1600 >1600 |
As of 2019 [update] , at least 1 billion 278 million adults aged 30–79 worldwide (over 16% of world population), including 626 million women and 652 million men, were estimated to have hypertension. [165] This is approximately 278 million up from 2014 [166] and almost double compared to year 1990, when there were estimated 648 million adults in the same age group living with the condition worldwide. [165]
Hypertension is slightly more frequent in men, [165] [166] in those of low socioeconomic status, [6] and it becomes more common with age. [6] It is common in high, medium, and low-income countries. [166] [167] In 2004, rates of high blood pressure were highest in Africa (30% for both sexes), and lowest in the Americas (18% for both sexes). Rates also vary markedly within regions with country-level rates as low as 22.8% (men) and 18.4% (women) in Peru and as high as 61.6% (men) and 50.9% (women) in Paraguay. [165] Rates in Africa were about 45% in 2016. [168]
In Europe, hypertension occurs in about 30–45% of people as of 2013 [update] . [14] In 1995 it was estimated that 43 million people (24% of the population) in the United States had hypertension or were taking antihypertensive medication. [169] By 2004 this had increased to 29% [170] [171] and further to 32% (76 million US adults) by 2017. [8] In 2017, with the change in definitions for hypertension, 46% of people in the United States are affected. [8] African-American adults in the United States have among the highest rates of hypertension in the world at 44%. [172] It is also more common in Filipino Americans and less common in US whites and Mexican Americans. [6] [173] Differences in hypertension rates are multifactorial and under study. [174]
Rates of high blood pressure in children and adolescents have increased in the last 20 years in the United States. [175] Childhood hypertension, particularly in pre-adolescents, is more often secondary to an underlying disorder than in adults. Kidney disease is the most common secondary cause of hypertension in children and adolescents. Nevertheless, primary or essential hypertension accounts for most cases. [176]
Hypertension is the most important preventable risk factor for premature death worldwide. [177] It increases the risk of ischemic heart disease, [178] strokes, [27] peripheral vascular disease, [179] and other cardiovascular diseases, including heart failure, aortic aneurysms, diffuse atherosclerosis, chronic kidney disease, atrial fibrillation, cancers, leukemia and pulmonary embolism. [12] [27] Hypertension is also a risk factor for cognitive impairment and dementia. [27] Other complications include hypertensive retinopathy and hypertensive nephropathy. [32]
Modern understanding of the cardiovascular system began with the work of physician William Harvey (1578–1657), who described the circulation of blood in his book "De motu cordis". The English clergyman Stephen Hales made the first published measurement of blood pressure in 1733. [180] [181] However, hypertension as a clinical entity came into its own with the invention of the cuff-based sphygmomanometer by Scipione Riva-Rocci in 1896. [182] This allowed easy measurement of systolic pressure in the clinic. In 1905, Nikolai Korotkoff improved the technique by describing the Korotkoff sounds that are heard when the artery is ausculted with a stethoscope while the sphygmomanometer cuff is deflated. [181] This permitted systolic and diastolic pressure to be measured.
The symptoms similar to symptoms of patients with hypertensive crisis are discussed in medieval Persian medical texts in the chapter of "fullness disease". [183] The symptoms include headache, heaviness in the head, sluggish movements, general redness and warm to touch feel of the body, prominent, distended and tense vessels, fullness of the pulse, distension of the skin, coloured and dense urine, loss of appetite, weak eyesight, impairment of thinking, yawning, drowsiness, vascular rupture, and hemorrhagic stroke. [184] Fullness disease was presumed to be due to an excessive amount of blood within the blood vessels.
Descriptions of hypertension as a disease came among others from Thomas Young in 1808 and especially Richard Bright in 1836. [180] The first report of elevated blood pressure in a person without evidence of kidney disease was made by Frederick Akbar Mahomed (1849–1884). [185]
Until the 1990s, systolic hypertension was defined as systolic blood pressure of 160 mm Hg or greater. [186] In 1993, the WHO/ISH guidelines defined 140 mmHg as the threshold for hypertension. [187]
Historically the treatment for what was called the "hard pulse disease" consisted in reducing the quantity of blood by bloodletting or the application of leeches. [180] This was advocated by The Yellow Emperor of China, Cornelius Celsus, Galen, and Hippocrates. [180] The therapeutic approach for the treatment of hard pulse disease included changes in lifestyle (staying away from anger and sexual intercourse) and dietary program for patients (avoiding the consumption of wine, meat, and pastries, reducing the volume of food in a meal, maintaining a low-energy diet and the dietary usage of spinach and vinegar).
In the 19th and 20th centuries, before effective pharmacological treatment for hypertension became possible, three treatment modalities were used, all with numerous side-effects: strict sodium restriction (for example the rice diet [180] ), sympathectomy (surgical ablation of parts of the sympathetic nervous system), and pyrogen therapy (injection of substances that caused a fever, indirectly reducing blood pressure). [180] [188]
The first chemical for hypertension, sodium thiocyanate, was used in 1900 but had many side effects and was unpopular. [180] Several other agents were developed after the Second World War, the most popular and reasonably effective of which were tetramethylammonium chloride, hexamethonium, hydralazine, and reserpine (derived from the medicinal plant Rauvolfia serpentina ). None of these were well tolerated. [189] [190] A major breakthrough was achieved with the discovery of the first well-tolerated orally available agents. The first was chlorothiazide, the first thiazide diuretic and developed from the antibiotic sulfanilamide, which became available in 1958. [180] [191] Subsequently, beta blockers, calcium channel blockers, angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers, and renin inhibitors were developed as antihypertensive agents. [188]
The World Health Organization has identified hypertension, or high blood pressure, as the leading cause of cardiovascular mortality. [192] The World Hypertension League (WHL), an umbrella organization of 85 national hypertension societies and leagues, recognized that more than 50% of the hypertensive population worldwide are unaware of their condition. [192] To address this problem, the WHL initiated a global awareness campaign on hypertension in 2005 and dedicated 17 May of each year as World Hypertension Day (WHD). Over the past three years, more national societies have been engaging in WHD and have been innovative in their activities to get the message to the public. In 2007, there was record participation from 47 member countries of the WHL. During the week of WHD, all these countries – in partnership with their local governments, professional societies, nongovernmental organizations and private industries – promoted hypertension awareness among the public through several media and public rallies. Using mass media such as Internet and television, the message reached more than 250 million people. As the momentum picks up year after year, the WHL is confident that almost all the estimated 1.5 billion people affected by elevated blood pressure can be reached. [193]
High blood pressure is the most common chronic medical problem prompting visits to primary health care providers in US. The American Heart Association estimated the direct and indirect costs of high blood pressure in 2010 as $76.6 billion. [172] In the US 80% of people with hypertension are aware of their condition, 71% take some antihypertensive medication, but only 48% of people aware that they have hypertension adequately control it. [172] Adequate management of hypertension can be hampered by inadequacies in the diagnosis, treatment, or control of high blood pressure. [194] Health care providers face many obstacles to achieving blood pressure control, including resistance to taking multiple medications to reach blood pressure goals. People also face the challenges of adhering to medicine schedules and making lifestyle changes. Nonetheless, the achievement of blood pressure goals is possible, and most importantly, lowering blood pressure significantly reduces the risk of death due to heart disease and stroke, the development of other debilitating conditions, and the cost associated with advanced medical care. [195] [196]
Hypertension in cats is indicated with a systolic blood pressure greater than 150 mmHg, with amlodipine the usual first-line treatment. A cat with a systolic blood pressure above 170 mmHg is considered hypertensive. If a cat has other problems such as any kidney disease or retina detachment then a blood pressure below 160 mmHg may also need to be monitored. [197]
Normal blood pressure in dogs can differ substantially between breeds but hypertension is often diagnosed if systolic blood pressure is above 160 mmHg particularly if this is associated with target organ damage. [198] Inhibitors of the renin-angiotensin system and calcium channel blockers are often used to treat hypertension in dogs, although other drugs may be indicated for specific conditions causing high blood pressure. [198]
Cardiology is the study of the heart. Cardiology is a branch of medicine that deals with disorders of the heart and the cardiovascular system. The field includes medical diagnosis and treatment of congenital heart defects, coronary artery disease, heart failure, valvular heart disease, and electrophysiology. Physicians who specialize in this field of medicine are called cardiologists, a specialty of internal medicine. Pediatric cardiologists are pediatricians who specialize in cardiology. Physicians who specialize in cardiac surgery are called cardiothoracic surgeons or cardiac surgeons, a specialty of general surgery.
Blood pressure (BP) is the pressure of circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term "blood pressure" refers to the pressure in a brachial artery, where it is most commonly measured. Blood pressure is usually expressed in terms of the systolic pressure over diastolic pressure in the cardiac cycle. It is measured in millimeters of mercury (mmHg) above the surrounding atmospheric pressure, or in kilopascals (kPa). The difference between the systolic and diastolic pressures is known as pulse pressure, while the average pressure during a cardiac cycle is known as mean arterial pressure.
Orthostatic hypotension, also known as postural hypotension, is a medical condition wherein a person's blood pressure drops when standing up or sitting down. Primary orthostatic hypotension is also often referred to as neurogenic orthostatic hypotension. The drop in blood pressure may be sudden, within 3 minutes or gradual. It is defined as a fall in systolic blood pressure of at least 20 mmHg or diastolic blood pressure of at least 10 mmHg after 3 minutes of standing. It occurs predominantly by delayed constriction of the lower body blood vessels, which is normally required to maintain adequate blood pressure when changing the position to standing. As a result, blood pools in the blood vessels of the legs for a longer period, and less is returned to the heart, thereby leading to a reduced cardiac output and inadequate blood flow to the brain.
A hypertensive urgency is a clinical situation in which blood pressure is very high with minimal or no symptoms, and no signs or symptoms indicating acute organ damage. This contrasts with a hypertensive emergency where severely high blood pressure is accompanied by evidence of progressive organ or system damage.
Peripheral artery disease (PAD) is a vascular disorder that causes abnormal narrowing of arteries other than those that supply the heart or brain. PAD can happen in any blood vessel, but it is more common in the legs than the arms.
Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases, heart failure, hypertensive heart disease, rheumatic heart disease, cardiomyopathy, arrhythmia, congenital heart disease, valvular heart disease, carditis, aortic aneurysms, peripheral artery disease, thromboembolic disease, and venous thrombosis.
Pulse pressure is the difference between systolic and diastolic blood pressure. It is measured in millimeters of mercury (mmHg). It represents the force that the heart generates each time it contracts. Healthy pulse pressure is around 40 mmHg. A pulse pressure that is consistently 60 mmHg or greater is likely to be associated with disease, and a pulse pressure of 50 mmHg or more increases the risk of cardiovascular disease. Pulse pressure is considered low if it is less than 25% of the systolic. A very low pulse pressure can be a symptom of disorders such as congestive heart failure.
Antihypertensives are a class of drugs that are used to treat hypertension. Antihypertensive therapy seeks to prevent the complications of high blood pressure, such as stroke, heart failure, kidney failure and myocardial infarction. Evidence suggests that reduction of the blood pressure by 5 mmHg can decrease the risk of stroke by 34% and of ischaemic heart disease by 21%, and can reduce the likelihood of dementia, heart failure, and mortality from cardiovascular disease. There are many classes of antihypertensives, which lower blood pressure by different means. Among the most important and most widely used medications are thiazide diuretics, calcium channel blockers, ACE inhibitors, angiotensin II receptor antagonists (ARBs), and beta blockers.
Essential hypertension is a form of hypertension without an identifiable physiologic cause. It is the most common type affecting 85% of those with high blood pressure. The remaining 15% is accounted for by various causes of secondary hypertension. Essential hypertension tends to be familial and is likely to be the consequence of an interaction between environmental and genetic factors. Hypertension can increase the risk of cerebral, cardiac, and renal events.
A hypertensive emergency is very high blood pressure with potentially life-threatening symptoms and signs of acute damage to one or more organ systems. It is different from a hypertensive urgency by this additional evidence for impending irreversible hypertension-mediated organ damage (HMOD). Blood pressure is often above 200/120 mmHg, however there are no universally accepted cutoff values.
Hypertensive heart disease includes a number of complications of high blood pressure that affect the heart. While there are several definitions of hypertensive heart disease in the medical literature, the term is most widely used in the context of the International Classification of Diseases (ICD) coding categories. The definition includes heart failure and other cardiac complications of hypertension when a causal relationship between the heart disease and hypertension is stated or implied on the death certificate. In 2013 hypertensive heart disease resulted in 1.07 million deaths as compared with 630,000 deaths in 1990.
The Dietary Approaches to Stop Hypertension or the DASH diet is a diet to control hypertension promoted by the U.S.-based National Heart, Lung, and Blood Institute, part of the National Institutes of Health (NIH), an agency of the United States Department of Health and Human Services. The DASH diet is rich in fruits, vegetables, whole grains, and low-fat dairy foods. It includes meat, fish, poultry, nuts, and beans, and is limited in sugar-sweetened foods and beverages, red meat, and added fats. In addition to its effect on blood pressure, it is designed to be a well-balanced approach to eating for the general public. DASH is recommended by the United States Department of Agriculture (USDA) as a healthy eating plan. The DASH diet is one of three healthy diets recommended in the 2015–20 U.S. Dietary Guidelines, which also include the Mediterranean diet and a vegetarian diet. The American Heart Association (AHA) considers the DASH diet "specific and well-documented across age, sex and ethnically diverse groups."
In medicine, systolic hypertension is defined as an elevated systolic blood pressure (SBP). If the systolic blood pressure is elevated (>140) with a normal (<90) diastolic blood pressure (DBP), it is called isolated systolic hypertension. Eighty percent of people with systolic hypertension are over the age of 65 years old. Isolated systolic hypertension is a specific type of widened pulse pressure.
Prehypertension, also known as high normal blood pressure and borderline hypertensive (BH), is a medical classification for cases where a person's blood pressure is elevated above optimal or normal, but not to the level considered hypertension. Prehypertension is now referred to as "elevated blood pressure" by the American College of Cardiology (ACC) and the American Heart Association (AHA). The ACC/AHA define elevated blood pressure as readings with a systolic pressure from 120 to 129 mm Hg and a diastolic pressure under 80 mm Hg, Readings greater than or equal to 130/80 mm Hg are considered hypertension by ACC/AHA and if greater than or equal to 140/90 mm Hg by ESC/ESH. and the European Society of Hypertension defines "high normal blood pressure" as readings with a systolic pressure from 130 to 139 mm Hg and a diastolic pressure 85-89 mm Hg.
A low sodium diet is a diet that includes no more than 1,500 to 2,400 mg of sodium per day.
Salt consumption has been extensively studied for its role in human physiology and impact on human health. Chronic, high intake of dietary salt consumption is associated with hypertension and cardiovascular disease, in addition to other adverse health outcomes. Major health and scientific organizations, such as the World Health Organization, US Centers for Disease Control and Prevention, and American Heart Association, have established high salt consumption as a major risk factor for cardiovascular diseases and stroke.
Orthostatic hypertension is a medical condition consisting of a sudden and abrupt increase in blood pressure (BP) when a person stands up. Orthostatic hypertension is diagnosed by a rise in systolic BP of 20 mmHg or more when standing. Orthostatic diastolic hypertension is a condition in which the diastolic BP raises to 98 mmHg or over in response to standing, but this definition currently lacks clear medical consensus, so is subject to change. Orthostatic hypertension involving the systolic BP is known as systolic orthostatic hypertension.
Hypertensive disease of pregnancy, also known as maternal hypertensive disorder, is a group of high blood pressure disorders that include preeclampsia, preeclampsia superimposed on chronic hypertension, gestational hypertension, and chronic hypertension.
Hypertension is managed using lifestyle modification and antihypertensive medications. Hypertension is usually treated to achieve a blood pressure of below 140/90 mmHg to 160/100 mmHg. According to one 2003 review, reduction of the blood pressure by 5 mmHg can decrease the risk of stroke by 34% and of ischaemic heart disease by 21% and reduce the likelihood of dementia, heart failure, and mortality from cardiovascular disease.
The Systolic Blood Pressure Intervention Trial (SPRINT) is a multi-center clinical trial that was performed from 2010 to 2015, and published in November 2015.
The results showed that cardiovascular disease and death are increased with low sodium intake (compared with moderate intake) irrespective of hypertension status, whereas there is a higher risk of cardiovascular disease and death only in individuals with hypertension consuming more than 6 g of sodium per day (representing only 10% of the population studied)