The prevalence of hypertension increases with age and exceeds 50% in the elderly. The special concern for the elderly is the increased incidence of systolic blood pressure (SBP), the fall of diastolic blood pressure (DBP) and the increased frequency of orthostatic hypotension.

The fall in diastolic BP results from decreased aortic impedence, a manifestation of not only aging but also other factors that accelerate arteriosclerosis including a high SBP. Higher SBP, left untreated, may accelerate aortic stiffness and perpetuate a vicious cycle.(1)

Another relevant factor is the increased frequency of postprandial hypotension and frailty; both relatively preventable. Overall, the clinical reality is that the control of hypertension is suboptimal.(2)(3)(4)

Blood Pressure Measurement: Proper Technique

It is important that the dimensions of the sphygmomanometer be appropriately sized for the patient. The sphygmomanometer bladder length should be 75-80 percent of the circumference of the upper arm and its width 50 percent of the upper arm length. Smaller cuffs may give readings that are inaccurately higher.(5)

The patient should avoid food, exercise, caffeine and smoking one hour prior to BP measurement.(6)Smoking two cigarettes (3.4 mg nicotine) will transiently elevate BP by 10/8 mm Hg for 15 minutes. Drinking coffee (200 mg caffeine) will elevate BP by up to 10/7 mm Hg for one to two hours.(7)

The patient should sit in a warm room for at least five minutes with the arm supported at the level of the heart. Hanging the arm will elevate SBP by 10 mm Hg because of hydrostatic pressure induced by gravity.(8)

To avoid the auscutatory gap, transient disappearance of Korotkof sounds as the cuff is deflated, feel the radial artery, inflate the cuff 30 mm Hg after disappearance of the radial pulse.(8) Auscultatory`gap is associated with carotid atherosclerosis.(9)

Initially check the BP in both arms and then use the arm with the higher reading for subsequent readings.(10)The stethoscope should be placed lightly over the brachial artery. Otherwise, the diastolic BP may be falsely lower by 10 to 15 mm Hg.(8)

Pseudohypertension

In some older patients, compression of the brachial artery, from arterial thickening caused by calcification, requires a cuff pressure greater than intra-arterial pressure. This will overestimate systolic and diastolic pressures by 10 mm Hg or more.(11)

Pseudohypertension should be suspected in the following situations:

• Presence of marked hypertension in the absence of end organ damage
• When treatment induces symptoms of hypoperfusion without excessive drop of blood pressure
• Positive Oslerís maneuver (palpable radial artery after inflation of the cuff to a level above systolic pressure).

Diagnosis

The United States Preventive Service Task Force (USPSTF) recommends measurement of blood pressure at each visit for patients over 21 years of age. History should include assessment of risk factors for cardiovascular disease, end organ damage and life style aspects that may be modified -- physical activity, alcohol consumption, smoking and dietary habits.

On physical examination, the clinician needs to emphasize accurate measurement of blood pressure, assessment of end organ damage and calculation of body mass index (BMI = weight in kilograms/height in meters squared).

As many as 25% of patients, more so among the elderly vis a vis the general population, who appear to exhibit mild hypertension at the physicianís office, may in fact be prone to medical office examination anxiety (white coat hypertension).(16) To avoid labeling such patients as hypertensives, a nurse should check the BP or have the patients check their BP at home. Patients should not be labeled hypertensive from the first visit unless they have end organ damage. Subsequent readings, rather than the first one, correlate with the cardiovascular risk.

Laboratory Investigations

Initial laboratory work should include urine analysis, basal metabolic profile, full blood count (CBC), fasting lipid profile (FLP), electrocardiography (EKG) and microalbuminuria if the patient is diabetic. Further tests depend on the history. Among the causes of secondary hypertension, renovascular hypertension is relevant to the elderly because of atherosclerotic renal artery stenosis.

Complications of Hypertension

Atherosclerosis is a major complication of hypertension. Coronary artery disease (CAD) needs special mention, as both systolic and diastolic BP are risk factors for CAD.(18) Throughout middle and old age, BP is strongly and directly related to vascular mortality with a threshold starting at 115/75 mm Hg.(19)

Hypertension is the most common risk factor for congestive heart failure (CHF).(20) In hypertensives, the risk of CHF is two-fold in men and three-fold in women. Among individuals aged 40 to 89 years followed for 20.1 years, of those who developed CHF, 91% had a prior history of hypertension. Hypertensive CHF is associated with a poor outcome -- only 24% of men and 31% of women survived five years. Left ventricular hypertrophy (LVH) predicted high risk of myocardial infarction (MI), arrhythmia and death.(21)(22)

Stroke is a complication that leads to high mortality and disability. The Systolic Hypertension Trial in Europe (Syst-Eur) showed that active treatment of hypertension reduced the total rate of stroke by 42%.(23) According to the Melbourne Risk Factor Study, hypertension is the most important risk factor for development of intracerebral hemorrhage.(24)

Findings from the Third National Health and Nutrition Examination Survey (HANES) showed that about 3.0 % of civilian, non-institutionalized US population had elevated serum creatinine, 70 % of whom were hypertensive. Among hypertensive individuals with high creatinine, 75 % received treatment. However, in only 11% of patients was it possible to reduce their BP to lower than 130/85 mm Hg.(25)

The Syst-Eur trial demonstrated a lower incidence of dementia in treated elderly patients with systolic hypertension.(26) If 1000 patients were treated for 5 years, 19 cases of dementia might be prevented.(26)

Treatment

Many trials have confirmed the benefit of treating hypertension in the elderly.(23)(27)(28)(29)(30)(31) Active treatment reduced total mortality by 13%, cardiovascular mortality by 18%, all cardiovascular complications by 26%, stroke by 30% and coronary events by 23%.

Treatment of hypertension started or changed in only 38% of visits to a physician despite documented hypertension for at least 6 months. The reason for this reluctance on the part of the physician is satisfaction with a high BP.(4)

Goal BP in the Elderly

The excellent trials in the field of hypertension are no replacement for sound clinical judgment. The treater must decide what goal BP best suits an individual patient. According to the Systolic Hypertension in the Elderly Program (SHEP), a SBP goal is 20 mm Hg lower if the baseline is between 160 and 180 mmHg and below 160 mm Hg if the initial value is above 180 mm Hg.(28)

Life style modification should be tried first. The Trial of Nonpharmachologic Interventions in the Elderly (TONE) showed that life style modification is effective in lowering the BP in the elderly.(32)(33) Sodium should be restricted to 2.3 g or 6 g of table salt.(12)

Although dietary restriction is an effective method of treatment, it needs to be instituted with care in the elderly because appetite declines with age, and salt restriction can lead to weight loss and orthostasis.(34) Weight loss in obese individuals has an additive effect to salt restriction.

While moderate alcohol intake of one or two drinks per day reduces cardiovascular risk,(35) alcohol consumption greater than two drinks per day leads to hypertension and the effect is dose related.(13)

Is There a Drug of Choice?

Because of sluggish auto regulation in the elderly, pharmacological therapy should be gentle, start low and go-slow, avoiding drugs that may cause postural hypotension.

The Seventh Report of the Joint Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC-7) recommends starting treatment with a thiazide diuretic, as it is effective, cheap and safe.(36) Another advantage of thiazide diuretics in the elderly is the positive calcium balance. The Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial (ALLHAT)(37) suggested that low dose thiazide diuretics have a better cardiovascular protective effect than ACE inhibitors and calcium channel blockers in patients with risk factors for coronary artery disease such as LVH, diabetes mellitus (DM) type 2, previous MI, stroke, hyperlipidemia, cigarette smoking or other atherosclerotic cardiovascular disease.(37)

The following drugs may be preferable in certain situations:

• Angiotensin converting enzyme inhibitors (ACEIs) are preferable in patients with heart failure, in patients with proteinuric chronic renal failure (CRF) and type 1 diabetics with nephropathy.(38)(39)(40)
• Angiotensin receptor blockers (ARBs) are effective in patients who cannot tolerate ACE inhibitors, in severe hypertension with EKG LVH and DM type 2 with microalbuminuria (N.B. there has been no similar ACE inhibitors trial).(41)
• β-blockers are preferred in patients with myocardial infarction (MI), as they improve survival and reduce ventricular tachycardia by 50%. They are beneficial in patients with heart failure without fluid overload, angina and atrial fibrillation.(42) With limited income a reality for the elderly, it is important to note that beta blockers are, compared to other antihypertensives, less expensive.
• Calcium channel blockers (CCB) are effective in situations where rate control is important, the patient has angina and in those conditions that make it difficult for patients to tolerate other drugs, e.g., COPD. ALLHAT showed no increase in incidence of MI with CCB.(34)

Special Patients

Supine Hypertension and Orthostatic Hypotension

This is a difficult situation because treatment of one aspect complicates the other. One option is to treat supine hypertension during the night with a nitroglycerin patch and remove it in the morning before ambulation, though care must be taken in a patient with frequent nocturia.(43)(44)

Hypertension, Postprandial Hypotension and Frailty

One study showed that hypertension was positively associated with postprandial hypotension and antihypertensive therapy was negatively associated with postprandial hypotension.(45) More studies are required in this field.

The Very Old

Currently, the opinion is divided about patients aged 85 years and above. In the August 2003 issue of the Journal of Gerontology, Dr. J.S. Goodwin initiated a debate by reviewing evidence which showed that higher levels of systolic and diastolic blood pressures are associated with increased survival in the very old.(46) This evidence was largely based on two population-based studies of the relationship of systolic and diastolic blood pressure level and 5-year mortality in men and women aged 85 and older.

One study enrolled 83% of the 85 and older population of Tempere, Finland (561 subjects) and the other enrolled 94% of the 85 and older population of Leiden, the Netherlends.(47)(47)(48) In both studies, the chance of 5-year survival is higher in those with a SBP >200 than among those with pressures of 120-140 mm Hg. However, these studies reported all causes of mortality and did not therefore provide a clear picture of the relationship between blood pressure and mortality. Poor health status, for example, was more common in patients with low blood pressure and, after adjusting for health status, the negative effect of low blood pressure disappeared.

The results of the ongoing Hypertension in the Very Old Trial (HYVET) will provide an answer to this debate. In this trial, 2100 patients, aged 80 and older with hypertension, enrolled in indapamide+perindopril vs. placebo groups. Until the study is reported, we need to rely on clinical judgment as we treat very old patients.

The Future

In May 1999, the Department of Veterans Affairs (VA) held a major invitational meeting entitled "Improvement in the Management of Hypertension in 2000 and Beyond."(49) The meeting was called in response to a study indicating that only 25% of hypertensive veterans had adequate levels of blood pressure control. The meeting proposed six future trials; the first two were deemed the most important:

1. A comparison of the degree of blood pressure control and long-term patient retention in patient-friendly HSTP (Hypertension Screening and Treatment Program) clinics versus the current VA primary care clinics.
2. A controlled evaluation of the effects of using an automatic home blood pressure-monitoring machine on success in controlling blood pressure and on cost effectiveness of care.
3. An evaluation of pulse wave velocity as an alternative to using SBP for the diagnosis and evaluation of the severity of hypertension and atherosclerosis on success in controlling blood pressure and on the cost effectiveness of care.
4. A test of the efficacy of various methods to prevent hypertension, including low sodium, high potassium, isotonic exercise and maintenance of normal body mass index.
5. An examination of the risk factors that underlie end stage renal disease to test whether intensive efforts to reduce blood pressure affects the appearance and rate of progression of end stage renal disease.
6. Evaluation of positive family history with other available characteristics, as a major risk factor for morbidity and mortality rates in patients with mild systolic/diastolic hypertension or with isolated systolic hypertension.

Results from these initiatives will eventually provide data that will help clinicians better manage hypertension in the elderly. Meanwhile, best practice for the hypertensive elderly will involve following proper techniques of blood pressure measurement, selecting the appropriate drug or drugs and achieving goal blood pressure as far as the patient situation permits.