Hypertension in the elderly: Some practical considerations
ABSTRACTData from randomized controlled trials suggest that treating hypertension in the elderly, including octogenarians, may substantially reduce the risk of cardiovascular disease and death. However, treatment remains challenging because of comorbidities and aging-related changes. We present common case scenarios encountered while managing elderly patients with hypertension, including secondary hypertension, adverse effects of drugs, labile hypertension, orthostatic hypotension, and dementia.
KEY POINTS
- Therapy should be considered in all aging hypertensive patients, even the very elderly (> 80 years old).
- Most antihypertensive drugs can be used as first-line treatment in the absence of a compelling indication for a specific class, with the possible exception of alpha-blockers and beta-blockers.
- An initial goal of less than 140/90 mm Hg is reasonable in elderly patients, and an achieved systolic blood pressure of 140 to 145 mm Hg is acceptable in octogenarians.
- Start with low doses; titrate upward slowly; and monitor closely for adverse effects.
- Thiazide diuretics should be used with caution in the elderly because of the risk of hyponatremia.
CASE 4: LABILE HYPERTENSION
A 74-year-old man with hypertension and diabetes mellitus comes to see you in the office. On physical examination, his blood pressure is 175/110 mm Hg. His blood pressure during his last visit 3 months ago was 120/75. He brings a log with him that shows random fluctuations in his blood pressure readings. He takes hydrochlorothiazide 25 mg daily for his blood pressure.
Hypertension in some patients continuously fluctuates between low and high levels. A study in Canada found that up to 15% of all adult hypertensive patients might have labile hypertension.52 In the presence of a normal average blood pressure, visit-to-visit blood pressure variability is usually considered a trivial matter. However, some but not all studies have shown that such visit-to-visit variability in blood pressure is an independent predictor of future cardiovascular events in hypertensive patients, independent of the mean systolic blood pressure.52–54
Blood pressure fluctuates from heartbeat to heartbeat, from morning to night, from winter to summer, and from sitting to standing, and it is prone to increase with exertion, stress, and other factors. But excessive fluctuations in the elderly are most likely the result of excessive stiffness of the arterial tree and a decrease in the windkessel (cushioning) function of the aorta. As a consequence, even small-volume changes in the intravascular system can trigger large blood pressure fluctuations.
There is some evidence that antihypertensive drug classes may differ in their effects on visit-to-visit blood pressure variability. In a 2010 study comparing the effects of different antihypertensive drugs on blood pressure variation, calcium channel blockers and non-loop diuretics were associated with less variation in systolic blood pressure, and calcium channel blockers reduced it the most.55
In the patient described above, switching to a low-dose calcium channel blocker with a thorough follow-up is a reasonable plan.
CASE 5: ORTHOSTATIC HYPOTENSION
A 73-year-old woman with long-standing hypertension complains of some dizziness, especially when getting out of bed in the morning. On physical examination, her blood pressure is 134/100 mm Hg sitting and 115/90 standing. She takes amlodipine 10 mg daily, enalapril 10 mg daily, and chlorthalidone 25 mg daily. Chlorthalidone had been added on her last visit 1 month before.
As a result of the increase in the number of elderly patients with hypertension and guidelines recommending better control in this age group, the number of elderly patients on anti-hypertensive drugs has risen significantly. At the same time, the elderly have increasingly presented with adverse effects of treatment.
Orthostatic hypotension is a drop in systolic pressure of 20 mm Hg or more or a drop in diastolic pressure of 10 mm Hg or more on standing, with or without symptoms. These are caused by cerebral hypoperfusion and include dizziness, lightheadedness, generalized weakness, visual blurring, and, in severe cases, syncope.
Alpha-blockers and nitrates have been most commonly implicated in causing orthostatic hypotension, due to venous pooling. Clearly, not all antihypertensive drugs are equal with regard to their venodilatory effects. Thiazide diuretics, by causing fluid volume depletion, and beta-blockers, by interfering with compensatory cardioacceleration with upright posture, are also commonly involved in causing an excessive blood pressure drop with standing.
Systolic orthostatic hypotension has been shown to be a significant and independent predictor of cardiovascular morbidity and death.56 Moreover, syncope and subsequent falls are an important cause of injury and death in the elderly.57 The clinical combination of hypertension and orthostatic hypotension is, therefore, especially challenging. A compromise between accepting a higher cardiovascular risk at either end of the spectrum with an added higher risk for fall at the lower end has to be made.
To prevent orthostatic hypotension in the elderly, it is important to avoid prescribing high-risk drugs. When starting antihypertensive therapy, a low dose should be used, and the dose should be titrated upward very slowly and cautiously. If orthostatic hypotension is suggested by the history or by the orthostatic test, which is warranted in all elderly hypertensive patients before starting or significantly altering therapy, the potential culprit drug should be withdrawn and the patient reassessed. Improved hydration, elevating the head of the bed, and taking the antihypertensive drug at night are ways to improve symptoms, but these remain largely unproven.
In this patient, the newly added chlorthalidone was stopped, and her symptoms improved.
PSEUDOHYPERTENSION
Since hypertension is defined by a numerical value, it is prudent that this value be accurate. Treating a falsely high reading or leaving a falsely low reading untreated will predispose the elderly patient to increased risk either way. One rare condition in the elderly that can give a falsely high blood pressure reading is pseudohypertension.
Pseudohypertension is a condition in which indirect blood pressure measured by the cuff method overestimates the true intra-arterial blood pressure due to marked underlying arteriosclerosis. The Osler maneuver can be used to differentiate true hypertension from pseudohypertension.58 This is performed by palpating the pulseless radial or brachial artery distal to the inflated cuff. If the artery is palpable despite being pulseless, the patient is said to be “Osler-positive” and likely has pseudohypertension.58
Pseudohypertension should be suspected if the patient has orthostatic hypotension despite normal blood pressure sitting and standing. Also, elevated blood pressure without appropriate target organ disease should raise the suspicion of pseudohypertension. Apart from the Osler maneuver, measuring the intraarterial pressure can confirm this diagnosis.
