An overview of Hypertension Blood Pressure

Hypertension

Hypertension or increased blood pressure is a major US health problem attracting the attention of public, physicians, and medical organizations. The aim of this thesis is to provide a brief yet a comprehensive review of the problem.

The definition of high blood pressure or hypertension is increase in the pressure exerted by the blood on the arterial walls as it passes through. Blood pressure reads as two numbers (for example 120/80). The nominator expresses the pressure within the arteries as the heart contracts (systolic), while the denominator points out the pressure within the arteries when the heart is in the relaxation phase of the cardiac cycle (diastolic). The normal blood pressure reading is 120/80 (+/- 10) mm Hg, with every increase of 20/10 mm Hg, cardiovascular risks of the disease double. Many believed that rise in the diastolic pressure is more risky than systolic rise. However, physicians know now that rise in the systolic blood pressure especially if sudden and unpredicted, is more risky and associated with strokes and cardiovascular accident especially above 50 years old (JNC report 7, p. 14-17).

Classification of hypertension according to severity considers the measured blood pressure. Normal individuals are those with a reading of 120/80 mm Hg. Individuals with blood pressure levels of 120-139 (systolic) or 80-89 (diastolic) are considered prehypertensive. Patients with stage 1 hypertension read measures of 140-159 (systolic) or diastolic reading of 90-99. In stage 2 hypertension, patients have higher systolic readings of more than 160 or diastolic more than 100 (JNC report 11-12). There are two points to stress in this context; first prehypertension is not a disease category. It means an individual is more prone to the risk of being hypertensive and it may be wise to look at his or her life style and recognize possible risk factors (obesity, smoking, overuse of alcohol…). Second, this classification does not consider the risk of other organs affected by hypertension (kidney, eye…); nor does it consider contributing factors to the disease (diabetes, renal disease) (JNC report 11-12).

Hypertension is also classified according to what causes it into two categories. First is primary or essential hypertension, which is more common with no clinically obvious cause for the disease. There may be some form of rigidity in the arterial wall (arteriosclerosis) because of precipitation of cholesterol plaques in the arteries walls. Genetic factors may play an important role in developing essential hypertension; however, identification of the possible gene(s) is not yet available. Hypertension may be a reflection of an underlying systemic disease. Chronic kidney diseases as renal failure result in renal hypertension. Renal hypertension may also result from an abnormality (narrowing) affecting the renal artery (renal artery stenosis). Diseases of the suprarenal endocrine gland (adrenal) may also cause hypertension. These diseases may be in the form of disturbed function as increased glucocorticoid (cortisone) secretion a disease known as Cushing syndrome. Alternatively, increased secretion of mineralocorticoids (adrenaline and nor-adrenaline) causes hypertension. This occurs mainly in cases of pheochromocytoma (an adrenal gland tumor). Secondary hypertension may also occur because of thyroid gland hypersecretion, or as more recently recognized, because of some sleep disorders (sleep apnea). It may be because of a major blood vessel abnormality as in cases of coarcitation of the aorta, or may be secondary to drug use as in chronic cortisone therapy (as an immunosuppressant drug) (JNC report 22-24).

Hajjar and Kotchen (199-206), performed comparative analysis of three National Health and Nutrition Examination Surveys (NAHNES), 1989-1991, 1991-1994 and 1999-2000 to identify the trends in prevalence, awareness and control of hypertension in the American population. Results of their study showed that nearly 29 percent of adults in USA suffer hypertension (that comes to over 58 million individuals). The results showed an increase of 3.7% in the prevalence of hypertension. The prevalence was highest in non-Hispanic Black American ethnic group (33.5%). As regards age prevalence, hypertension increases with advancing age. In this study, age group over 60 years old showed prevalence of 65.4%. Gender differences showed the disease is more prevalent in females of age group 65-70 years old (38% compared to 31% of males of the same age group). Increased body weight was significantly associated with hypertension. Awareness of the disease has increased by 6% during the period 1989 to 2000 and 58% of participants (total 5448 individuals) were under treatment, however, only 31% were controlled. Three groups showed the least rate of disease control; they were Mexican-Americans, females and individuals aged 60 years or older. Despite advances made in medications and treatment protocols, hypertension remains a major health problem of the American population.

Accurate measurements of blood pressure are the cornerstone of diagnosis and follow up. The device used is the sphygmomanometer; it may be mercury working (like the thermometer), digital or electronic. The risk of mercury escaping from its container led to the frequent use of other types; however, there are concerns about their accuracy. Therefore, these equipments need regular calibration and adjustment. On measuring blood pressure, the patient should be seated with the feet touching the ground, arms supported and with no previous exercise, smoking or drinking beverages for at least 30 minutes before the test. The examiner should take at least two readings and take the average. It is always more accurate to use the stethoscope (auscultation) method rather than feeling the pulse ((JNC report 18-19).

Evaluation of the hypertensive patient in a clinical setting aims at four objectives, first to assess the patient life style, for example types of food the patient eats, practicing exercise, kind of job, and how emotional the patient is. Second, is to assess cardiovascular risk factors as previous cardiac disease, presence of a major blood vessels anomaly, history of previous or chronic medications. Third, is to identify the presence of possible causes of hypertension (secondary hypertension) and the presence of coexistent diseases that may affect the treatment plane. Finally, is to examine the impact of hypertension on other organs as the eye and kidney. In a clinical setting, it is a better practice to measure blood pressure in both arms as significant difference may point to coarcitation of the aorta. General examination and heart examination are performed with eye fundus examination to fulfill the aims of evaluation. Abnormalities of the heart rate (reduced or increased) may signal higher cardiovascular risk. Laboratory testing usually begins by 12 channels electrocardiography to have full information on the patient's heart. Laboratory testing aiming to assess the kidney condition includes testing for albumin, kidney function tests, and albumin creatinine ratio. Patients usually need blood tests to determine low-density lipoproteins (LDL), lipoprotein cholesterol study, and triglycerides as abnormalities may point to arteriosclerosis (JNC report 20-21).

In dealing with health problems, prevention and prophylaxis are always golden rules. Excess weight, increased dietary intake of sodium and decreased intake of potassium, lack of exercise and reduced intake of fresh vegetables and fruits are factors closely associated with the risk of hypertension. Obstacles to prevention, on individual level, are many. They include cultural reasons as regards the type and amount of food eaten, lack of healthy food choices at schools and working places, larger food serving in restaurants, and lack of exercise programs in schools. Communities serving civil societies are important partners in prevention. The proposal provided by the American Public Health Association to reduce sodium intake by 50% over 10 years to lessen hypertension risk is a good pattern of alerting the public with ways to prevent health problems (JNC report 15-16).

Hypertension is an important predisposing factor for coronary artery disease, congestive heart failure and chronic kidney disease, therefore it deserved the name ‘silent killer' (Hypertension- ‘The Silent Killer'. Briefing statement of the Faculty of Public Health. The Royal Colleges of Physicians of the United Kingdom). The aim of treating hypertension is to lessen the risk of cardiovascular and kidney complications. All treatments start by modifying the patient life style. Adopting a healthy lifestyle in eating habits, exercise, moderation in alcohol use and stop smoking are essential both in prevention and in treatment. A Latin proverb accurately describes this line of prevention and treatment. It says Optima medicina temperantia est; which means moderation is the best medicine (Post Details: Latin Proverbs about Medicine: Physician, heal thyself (from <http://latin.bestmoodle.net.index.php/proverbia/2006/06/20/proverbia_about_doctors>).

The primary goal of treatment is to achieve a blood pressure level less than 140/90; treatment usually starts by recognizing unhealthy lifestyle behaviors and modifying them, if this fails to bring blood pressure level to normal, pharmacotherapy starts. Thiazide diuretics are the drug of choice to begin with in stage 1 hypertension, if a patient does not respond, a second drug (a bet blocker, a calcium channel antagonist…). In stage 2, it is justifiable to start with a combination of two drugs. More than 60% of hypertensive patients do not respond to one drug treatment, therefore the use of multiple drug therapy may be initially used either on separate prescriptions of in fixed dose combinations. The starting doses are usually below those mentioned in clinical trials, tailoring the dose according to follow up results follow. This is one reason why monthly follow up visits are important, although stage 2 patients may need more frequent initial follow up visits. Other reasons are to evaluate the efficiency of the drug combination used and to check for risk or drug side effects. When the patient reaches aimed blood pressure level, follow up visits can be every three-6 months (JNC report 26-32).

Despite advances in diagnostic techniques and drugs used, there are cases of refractory hypertension (difficult to treat), where drug combinations used do not achieve the treatment goal. Moser and Setaro (385-392) described a case of an obese old female (70 years old) who was receiving a fixed drug combination of three antihypertensive drugs (including a thiazide diuretic). Her blood pressure level was still in stage 2, in addition to these drugs, she received ibuprofen for osteoarthritis. This called for further advanced investigations as repeated blood pressure measuring in non-clinical settings (at home, at work or ambulatory measurements), and echocardiography. Advanced laboratory tests for possible causes of secondary hypertension (hormonal assessment, VMA, Valinyl Mandelic Acid, level for pheochromocytoma, investigating the aorta and renal arteries for abnormalities, and in view of the patient's overweight, sleep lab studies) were performed. As all tests (except sleep lab studies) were negative, they discontinued ibuprofen, as it may predispose to hypertension, and was replaced by another safer drug (acetaminophen). The patient was seriously encouraged to reduce weight, and the diuretic dose was increased for fear of blood volume overload on the patient's heart.

Based on the frequency of such refractory cases and because of advances made in diagnosis, pharmacotherapy and clinical trials suggested drug combinations. Moser (9-14), suggested an update to JNC report of 2004 that addresses the advances achieved in the last few years to shape an up to date guidelines.

Hypertension is a serious health hazard as it affects nearly one in four adult Americans. It increases the risk of cardiovascular accidents and stroke (causes number one and three as the common causes of death in the US). Its definition is rise of blood pressure above 140/90. There is a change of epidemiology trends in the last few years, in the form of increased prevalence. This calls for more efforts for prevention and updated guidelines for diagnosis and treatment.

Works Cited

US Department of Health and Human Services. National Institutes of Health. National Heart and Blood Institute. Complete Report: The Seventh Report of Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure. By Chobanian, A V. (Chair). 2004. 19/05/2008 <http://www.nhlbi.nih.gov/jnc7/full/pdf>

Hajjar, I and Kotchen, T A. Trends in Prevalence, Awareness, Treatment and Control of Hypertension in the United States, 1988-2000. JAMA. Vol. 290 (2) 2003. p. 199-206.

Moser, M and Setaro, J F. Resistant or Difficult-to-Control Hypertension. The New England Journal of Medicine. Vol. 355(4) 2006. p. 385-392

Moser, M. Hypertension Treatment Guidelines: Is It Time for an Update. The Journal of Clinical Hypertension. Vol. 9 (1) 2007. p. 9-14