Essential Hypertension

• The student will be able to discuss the medical rationale for treating hypertension.

• The student will demonstrate ability to make a diagnosis of hypertension and will be able to identify factors that interfere with the reliability of blood pressure measurements.

• The student will be able to list the four main objectives of the clinical evaluation of a patient with hypertension and will be able to discuss the components of each.

• The student will be able to discuss treatment strategies for patients with hypertension according to The Fifth Report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure (JNC V).1

Hypertension is a major therapeutic challenge to health care providers. It is a major risk factor for cardiovascular morbidity, heart failure, heart attack, stroke, and kidney failure.

Anti-hypertensive therapy is effective in reducing or eliminating the increased morbidity/mortality associated with hypertension. Hypertension is an asymptomatic disease for many years. Approximately 50 million people in the United States have high blood pressure.

The blood pressure should be taken with the subject seated and relaxed, and with the arms suitably bared. Avoid extraneous factors that may alter the blood pressure, such as:

• recent smoking or eating
• anxiety
• exertion
• cold
• medications (estrogens, steroids, adrenergic drugs, etc.)
• bladder distension.

• improper cuff size
• improper placement of cuff
• inaccurate manometer
• variations due to arrhythmias.

Purposes of Clinical Evaluation

In the clinical evaluation of a patient with confirmed hypertension, the physician should:

• Search for secondary causes:

• coarctation of the aorta
• chronic renal disease
• renovascular disease
• glomerulonephritis
• pheochromocytoma
• primary aldosteronism
• Cushing's syndrome
• intracranial lesions
• estrogens/oral contraceptives, steroidal and non-steroidal anti-inflammatory agents, nasal decongestants, appetite suppressants, and the tricyclic antidepressants
• excessive alcohol intake.

• Search for target organ disease.

• Search for additional risk factors:

• dyslipidemia
• smoking
• diabetes mellitus
• physical inactivity
• obesity
• family history.

• Educate the patient and encourage compliance.

Medical History

A medical history should include the following:

• family history of high blood pressure, premature CHD, stroke, CVD, diabetes mellitus, and dyslipidemia
• patient history or symptoms of cardiovascular, cerebrovascular, or renal disease; diabetes mellitus; dyslipidemia; or gout
• known duration and levels of elevated blood pressure
• history of weight gain, leisure-time physical activities, and smoking or other tobacco use
• dietary assessment, including sodium intake, alcohol use, and intake of cholesterol and saturated fats
• results and side-effects of previous antihypertensive therapy
• symptoms suggesting secondary hypertension
• psychosocial and environmental factors (e.g., family situation, employment status and working conditions, educational level) that may influence blood pressure control
• use of drugs that may influence blood pressure (e.g., oral contraceptives, steroids, nonsteroidal anti-inflammatory drugs, nasal decongestants and other cold remedies, appetite suppressants, cyclosporine, erythropoietin, tricyclic antidepressants, and monoamine oxidase inhibitors).

• two or more blood pressure measurements with patient supine or seated and standing
• verification of blood pressure in the contralateral arm
• height and weight
• funduscopic examination of eyes for hypertensive changes
• examination of neck for thyroid enlagement, bruits, distended veins
• examination of the lungs
• examination of the heart for increased rate, size, precordial heaves, rhythm, gallops, murmurs
• examination of abdomen for enlarged kidneys, masses, aortic dilitation, bruits
• examination of extremities for peripheral pulses, edema, etc.
• neurological assessment

The following baseline laboratory tests should be obtained before initiating therapy:

• CBC
• urinalysis
• creatinine and/or BUN
• serum potassium, calcium
• uric acid
• ECG
• fasting blood glucose
• cholesterol

Additional diagnostic procedures may be indicated to discover secondary hypertension in patients:

• in whom age, history, physical examination, severity of hypertension, or initial laboratory findings suggest secondary hypertension

• whose blood pressures are responding poorly to drug therapy

• with well-controlled hypertension whose blood pressures begin to increase

• with accelerated or malignant hypertension

• with sudden onset of hypertension.

Programs for the primary prevention of hypertension are currently being developed, implemented, and evaluated. These programs involve either the general population (population strategy) or a population of patients at risk for the development of hypertension (targeted strategy).

These programs are attempting to keep patients from developing hypertension by changing behaviors associated with becoming hypertensive. Life-style modifications that have shown promise in the primary prevention of hypertension have targeted persons with a high sodium intake, an excessive caloric intake, physical inactivity, excessive alcohol consumption, and a low potassium intake.

Community programs may become an important strategy for the primary prevention of hypertension and for monitoring progress and encouraging compliance in persons with hypertension.

The goal of hypertensive treatment is to prevent morbidity and mortality associated with high blood pressure.
Most patients with persistent systolic levels above 160 mmHg and/or diastolic levels above 95 mmHg should receive antihypertensive therapy. Some experts believe that drug therapy should be initiated if the diastolic pressure remains above 90 mmHg despite vigorous attempts with non-pharmacologic measures, this being especially true in those with other significant risk factors.

Target blood pressure is less than 140/90.

The decision as to which drug to use first can usually be made on the basis of age, race, the presence of other medical problems, side effects, long-term safety, and cost. If one drug is found to be well-tolerated but only partially effective, the addition of a second drug of another class is rational. Half or more of patients will probably require a second drug, and about 10% will require three.

Because diuretics and á-blockers have been shown to reduce cardiovascular morbidity and mortality in controlled clinical trials, these two classes of drugs are preferred for initial drug therapy.

This recommendation from the JNC V report counters previous trends away from these agents because of the potential for adverse effects on lipid and glucose metabolism.3

Alternative drugs recommended for monotherapy include the calcium antagonists, angiotensin-converting enzyme (ACE) inhibitors, d-1 receptor blockers, and the d-á-blocker.

Although these alternative drugs have potentially important benefits, they have not been used in long-term controlled trials to demonstrate their efficacy in reducing morbidity and mortality, and therefore should be reserved for special indications or when diuretics and á-blockers have proved unacceptable or ineffective.

The d2-agonist, Clonidine, tends to produce annoying side-effects in a large number of patients and is not recommended for monotherapy. Clonidine is commonly used for monotherapy and in combination with other agents in LSU-S clinics because of its low cost.

Aspects of Medication Pharmacology

Certain aspects of medication pharmacology are particularly important in gaining long-term patient adherence to medication. These include:

• minimize dose frequency (very few patients require dosage of more than twice a day)
• give drug time to work (should know when a particular medication has reached full effect)
• know drug side effects (helpful in anticipating side effects)
• utilize convenient dose forms
• consider monthly cost of medication

The physician should stress the following points with the patient:

• seriousness and lifelong nature of hypertension
• importance of taking medication as directed to maintain control
• asymptomatic nature of the disease
• importance of keeping follow-up appointments

Appreciation is expressed to the JNC IV and V, major sources of the information contained herein.

The Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure

The Fifth Report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure (JNC V). Arch Intern Med 1993;153.

Treatment of Hypertension: A Current Perspective. The Newspaper of Cardiology, June 1990.

New Insights and New Approaches for the Treatment of Essential Hypertension. Mark C. Houston, M.D. American Heart Journal, p. 911-951, April 1989.