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Hypertension (High Blood Pressure)
Gary F. Milechman, MD, FACC and Ernest H. Rosenbaum, MD


Hypertension (high blood pressure) is a medical condition in which the blood pressure is chronically elevated. Hypertension is one of the major risk factors for strokes, heart attacks, heart failure and aneurysms and is a leading cause of chronic renal (kidney) failure. Even moderate elevation of arterial blood pressure leads to a shortened life expectancy.

When a person's systolic blood pressure is consistently 140mmHg or greater, and/or their diastolic blood pressure is consistently 90mmHg or greater, they are considered to have hypertension.

Mayo Clinic website specifies blood pressure is normal if it's below 120/80. In patients with diabetes mellitus (type 2 diabetes) or kidney disease, studies have shown that blood pressure over 130/80 mmHg should be considered high and warrants further treatment.

The only test for hypertension is a blood pressure measurement. If not in the presence of other disorders, hypertension usually produces no symptoms although some people report headaches, fatigue, dizziness, blurred vision, facial flushing or tinnitus.

Hypertension is often confused with mental tension, stress and anxiety. While chronic anxiety and/or irritability are associated with poor outcomes in people with hypertension, those stresses alone do not cause it.

Hypertension can be classified as either essential (primary) or secondary.
Essential hypertension: Of those with hypertension, 90% to 95% have the essential form. Although no clear medical cause can be determined in essential hypertension, several factors may contribute to it, including salt sensitivity, renin kidney chemical imbalance (homeostasis), insulin resistance, genetic family predisposition and age. Essential hypertension occurs commonly in combination with diabetes mellitus (type 2), combined hyperlipidemia (elevated cholesterol), and central obesity. Primary or essential hypertension is more common in adolescents and has multiple risk factors, including obesity and a family history of hypertension.

Secondary hypertension: In this case, high blood pressure is caused by another condition, such as kidney disease or certain tumors (especially adrenal gland tumors). Most of the individuals with secondary hypertension probably have an endocrine or kidney defect that, if corrected, could bring blood pressure back to normal values. Secondary hypertension can also be caused by certain medications (especially NSAIDS [Motrin/ibuprofen] and steroids).

Factors contributing to essential hypertension
1. Salt sensitivity Approximately 60% of those with essential hypertension are responsive to sodium intake. When in excess, salt in the body affects how well the kidneys function. The kidneys remove excess salt and water from the blood (both of which are excreted as urine).

2. When the kidneys are not functioning properly, fluid builds up around cells and in the blood and the heart has to work harder, by raising the blood pressure, to move the blood through your system. The heart can be weakened by this extra work.

Other potential causes
1. Sleep apnea -- A common, under-recognized cause of hypertension
2. Genetics -- Hypertension is inherited in 30% of those with essential hypertension
3. Age -- As a person ages, there is an increase in the number of collagen fibers in artery walls, stiffening blood vessels and requiring a higher pressure to move your blood

Hypertensive elevated blood pressure causes both short- and long-term effects on many organs, increasing the risk for:
- Stroke (cerebrovascular accident or CVA)
- Heart attack (myocardial infarction)
- Heart failure (hypertensive cardiomyopathy) due to chronically high blood pressure
- Damage to the retina (eye) (hypertensive retinopathy)
- Chronic renal failure (hypertensive nephropathy) due to chronically high blood pressure

Hypertension in Children and Adolescents
Blood pressure varies widely in children and adolescents and merits repeat conversations and treatment if elevated. Averaging multiple blood pressure readings over weeks to months can be helpful. Hypertension as a chronic disease is found in 2-5% of children. It could be secondary to disease or essential hypertension (real disease, aortic coarctation and endocrine disease). It also relates to family hypertension, low birth weight and excessive weight. Hypertension in children is a future risk factor for adults that can cause cardiovascular disease, left ventricular hypertrophy, coronary artery disease, atherosclerosis and diastolic dysfunction.1

Pediatric hypertension is diagnosed with an elevated blood pressure on three different visits and pre-hypertension on three or more different visits. It is classified as pressures greater than 120/80 but does vary with sex and age.

Pediatric hypertension is often not noted because of lack of knowledge of normal blood pressure ranges, which depend on age, sex and height, and lack of awareness of the patient's previous blood pressure readings. Tables are available to help adjust blood pressures for the appropriate correct levels. Pediatric hypertension occurs in about 30% of overweight children, a positive family history, or in both groups. It is important to diagnose pre-hypertension in view of the current pediatric/adolescent obesity epidemic. It also occurs as an asymptomatic chronic condition.

Lifestyle behaviors to reduce hypertension
- Weight reduction and regular aerobic exercise are recommended as the first steps in treating mild to moderate hypertension. Regular mild exercise improves blood flow and helps to reduce resting heart rate and blood pressure. These steps are highly effective in reducing blood pressure, although drug therapy is still necessary for many patients with moderate or severe hypertension to bring their blood pressure down to a safe level.

- Reducing sodium (salt) in your diet has proved to be very effective: it decreases blood pressure in about 60% of people. Many people choose to use a salt substitute to reduce their salt intake. In addition, an increase in daily calcium intake (thereby increasing dietary potassium) has also been shown to be highly effective in reducing blood pressure by supporting kidney function.

- The DASH diet (Dietary Approaches to Stop Hypertension) is rich in fruits and vegetables and low fat or fat-free dairy foods. National Institutes of Health sponsored research has shown this diet to be effective.

- Cessation of tobacco and alcohol use has been shown to lower blood pressure. By stopping cigarette smoking, people with hypertension reduce their risk of many dangerous outcomes of hypertension, such as stroke and heart attack.

- Relaxation therapy, such as meditation, that reduces environmental stress. High sound levels and over-illumination can be an additional method of causing hypertension.2,3 Research suggests listening to music may expand blood vessels, increase blood flow. When people listen to music that makes them happy, blood flow, a key measure of heart health, improves.4 Audiotapes designed to promote relaxation, and to watch videos designed to induce laughter increased blood flow 19% during the laughter and 11% during relaxation.5

Facts:
1. An elevated LDL cholesterol above 160 mg/dl and a decreased HDL cholesterol below 40 mg/dl are important predictors of heart disease. Lowering LDL with lifestyle changes and medications will reduce the risk of heart disease.

2. Ways of raising HDL are under investigation.

3. There are heart-healthy values with increasing omega-3 food intake.

4. Vision preservation - delaying cataracts - through vitamin/antioxidant intake. This may help delay age-related macular degeneration, the leading cause of blindness in older people.

5. A lower glycemic diet is important, which also pertains to non-diabetics - 93% of our population.

6. Diet does affect health (partly genetic). Nutrigenomics - the study of how dietary constituents interact with genes to affect your health. Work is being done at the HNRCAs Nutrition and Genomics Laboratory at Tufts, a lab seeking to identify genes involved in longevity and healthy aging and how they respond to nutrition.

7. Vascular dementia - walking daily can reduce risk 70% and may substantially reduce the risk not only for vascular dementia but also slow progressive memory loss and cognitive function similar to Alzheimer's disease.6 The University Hospital, S. Orsola Malpighi in Bologna, Italy studied brain aging of 749 men and women over age 85 free from cognitive assessment. Twenty three percent walked for exercise daily, and others did home gardening. 7

Those who did moderate exercise activity retained better cognitive function estimated at a 73% risk reduction for vascular dementia versus those who exercised the least. Causal link not yet proved and may be an effect from better blood flow to the brain and possibly cholesterol control, thus reducing risk of stroke - improves stream of blood flow, reduction in cortisol and other brain toxic stress hormones which can be protective. Exercise also reflects the use of healthier lifestyles and possibly better mental and social stimulation with a more active life.

The Control of Abnormal Blood Pressure
Approximately 72 million American adults have a high blood pressure or hypertension problem and often show no symptoms until a catastrophic event, such as a heart attack or stroke, has occurred.

High blood pressure taxes the arteries and promotes arteriosclerosis - hardening of the arteries - all over the body from the brain, kidneys, eyes, heart, and legs, and can lead to kidney failure, heart attack, stroke, blindness and even death. Yet, blood pressures are not checked in a systematic way, which could help control a problem that can affect all the organs of the body.

There are many causes of high blood pressure, which could include kidney disease, hormonal endocrine tumors of the adrenal glands, increased thyroid activity or drug interactions. Most of the causes of high blood pressure are what has been called idiopathic - a disease with an unknown cause.

Lifestyle changes can make a difference in helping to control high blood pressure:
1. Reducing salt intake. The average person consumes somewhere between 5 and 9 gm of salt with the ideal to be less than 6 gm or less than 2 gm of sodium per day.
2. Control of overweight and obesity problems, eating fewer calories, and a diet emphasizing fruit and vegetables.
3. Not smoking.
4. Minimal or no drinking.

Often when lifestyle changes have been followed, the blood pressure can remain high, and there will be a need for medication to control the blood pressure and reduce the body's excessive water and salt content to help relieve pressure in the blood vessels, which can lead to serious diseases, mainly heart, stroke and kidney failure. Unfortunately, some of the drugs do have side effects, and these have to be monitored and controlled by a physician.

The projected normal blood pressure, which was 140 systolic over 90 diastolic, has now been reduced with the suggested level of 120/80. Pressures above this level merit observation, as these may be pre-hypertension pressures that frequently lead to subsequent hypertension.
1. A physical activity program is essential not only for good health but to help control blood pressure, as well as promote relaxation and reduce anxiety and depression.
2. It has been noted that women experiencing hot flashes often have elevated blood pressure levels.
3. The use of lipid (cholesterol) lowering drugs, such as the statin drugs, can also help in controlling elevated blood pressure.
4. Persons in pain often have elevated blood pressure, but drugs (pain killers) can also cause an elevation in blood pressure.

It is well-known that often when a person visits a doctor because of the white coat, office atmosphere, and longer waits to see the doctor can result in elevated blood pressure when tested by the doctor. It is wise to have your own blood pressure kit that can be found in any drug store and have frequent home measurements that will end up being more accurate, as they are being taken under normal living activities. It is wise to take your home blood pressure cuff with you when you visit your physician or nurse, and have her compare readings on your blood pressure equipment to that of the doctor's as a way of calibrating your apparatus for accuracy.

African Americans are estimated to be four times more likely than Caucasians to develop kidney failure from hypertension. Other comorbidities include diabetes, which also puts you at risk for kidney failure. A gene has been linked to high blood pressure. This gene affects the kidney's ability to process salt, which is a problem for a smaller percent of patients with high blood pressure and can lead to improved treatments. The gene, STK39, is found in those with higher blood pressure and future hypertension.8

A low salt diet may not be the link to help control blood pressure, especially in those who have the gene variant. About 20% of people had one or two copies of this particular gene variant, which produces a protein involving regulating the way the kidneys process salt, which is a key factor in determining blood pressure in this group. 9

Those with high blood pressure are more at risk for heart attacks, heart failure, stroke, and kidney disease.
- Maintaining a healthy weight, controlling sodium intake, exercising, and limiting coffee and alcohol consumption may also be of help.
- Controlling blood pressure with medications, such as ACE (angiotensin-converting enzyme) inhibitors or ARBs (angiotensin-receptor blockers), can help lower blood pressure, as well as other medications prescribed by your physician in addition to learning how to relax, use meditation and reduce stress in your life.
- Those with high blood pressure are more at risk for heart attacks, heart failure, stroke, and kidney disease.

References
1
Matthew L. Hansen, MD; Paul W. Gunn, BS; David C. Kaelber, MD, PhD, Underdiagnosis of Hypertension in Children and Adolescents, JAMA., 2007;298(8):874-879
2
Alexandros S. Haralabidis, Konstantina Dimakopoulou, Federica Vigna-Taglianti, Matteo Giampaolo, Alessandro Borgini, Marie-Louise Dudley, Goran Pershagen, Gosta Bluhm, Danny Houthuijs, Wolfgang Babisch, Manolis Velonakis, Klea Katsouyanni, Lars Jarup for the HYENA Consortium Acute effects of night-time noise exposure on blood pressure in populations living near airports European Heart Journal, February 12, 2008
3
L Barregard, E Bonde, and E Ohrstrom Risk of hypertension from exposure to road traffic noise in a population-based sample Occup. Environ. Med., June 1, 2009; 66(6): 410 - 415.
4
P.M. Mitrovic, B. Stefanovic, Z. Vasiljevic, M. Radovanovic, N. Radovanovic, G. Krljanac, D. Rajic, G. Matic, A. Novakovic, M. Ostojic, Long-term effects of music therapy on patients with acute myocardial infarction and previous revascularization; 7-year experience, European Heart Journal ( 2009 ) 30 ( Abstract Supplement ), 337
5
Hsin-Yi Tang, Verna Harms, Sarah M. Speck, Toni Vezeau, A Randomized Trial of Music Versus Audio Guided-relaxation Training to Decrease Blood Rressure in an Elderly Population American Heart Association, 62nd High Blood Pressure Research Conference 2008
6
L. Flicker Life style interventions to reduce the risk of dementia Maturitas, 2009 Aug 20;63(4):319-22
7
G. Ravaglia, MD, P. Forti, MD, A. Lucicesare, MD, N. Pisacane, MD, E. Rietti, MD, M. Bianchin, MD and E. Dalmonte, MD Physical activity and dementia risk in the elderly Findings from a prospective Italian study Neurology 2008;70:1786-1794
8
Adebowale Adeyemo1, Norman Gerry, Guanjie Chen, Alan Herbert, Ayo Doumatey, Hanxia Huang, Jie Zhou, Kerrie Lashley, Yuanxiu Chen, Michael Christman, Charles Rotimi, A Genome-Wide Association Study of Hypertension and Blood Pressure in African Americans, PLoS Genet 5(7): e1000564. doi:10.1371/journal.pgen.1000564
9
Ying Wang, Jeffrey R. O'Connell, Patrick F. McArdle, James B. Wade, Sarah E. Dorff, Sanjiv J. Shah, Xiaolian Shi, Lin Pan, Evadnie Rampersaud, Haiqing Shen, James D. Kim, Arohan R. Subramanya, Nanette I. Steinle, Afshin Parsa, Carole C. Ober, Paul A. Welling, Aravinda Chakravarti, Alan B. Weder, Richard S. Cooper, Braxton D. Mitchell, Alan R. Shuldiner, and Yen-Pei C. Chang, Whole-genome association study identifies STK39 as a hypertension susceptibility gene PNAS January 6, 2009 vol. 106 no. 1 226-231



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