What is the proper workup of a patient with hypertension?
ABSTRACTBecause hypertension is common and many tests are available, an uncritical approach to laboratory and radiologic evaluation leads to unnecessary expenses. However, in most patients, accurate blood pressure measurement, a focused history and physical examination, and a handful of basic tests are enough. In this review we address the key questions in the evaluation of the patient with an elevated pressure reading, ie, does the patient have sustained high blood pressure? And if so, is the hypertension primary or secondary, are other cardiovascular risk factors present, and is there evidence of target organ damage?
KEY POINTS
- To confirm the diagnosis of hypertension, multiple readings should be taken at various times.
- Proper technique is important in measuring blood pressure, including using the correct cuff size, having the patient sit quietly for 5 minutes before taking the pressure, and supporting the arm at the level of the heart.
- If white-coat hypertension is suspected, one can consider ambulatory or home blood pressure measurements to confirm that the hypertension is sustained.
IS THE HYPERTENSION PRIMARY OR SECONDARY?
Most patients with hypertension have primary (“essential”) hypertension and are likely to remain hypertensive for life. However, some have secondary hypertension, ie, high blood pressure due to an identifiable cause. Some of these conditions (and the hypertension that they cause) can be cured. For example, pheochromocytoma can be cured if found and removed. Other causes of secondary hypertension, such as parenchymal renal disease, are infrequently cured, and the goal is usually to control the blood pressure with drugs.
The sudden onset of severe hypertension in a patient previously known to have had normal blood pressure raises the suspicion of a secondary form of hypertension, as does the onset of hypertension in a young person (< 25 years) or an older person (> 55 years). However, these ages are arbitrary; with the increasing body mass index in young people, essential hypertension is now more commonly diagnosed in the third decade. And since systolic pressure increases throughout life, we can expect many older patients to develop essential hypertension.7 Indeed, current guidelines are urging us to pay more attention to systolic pressure than in the past.
WHAT IS THE PATIENT’S CARDIOVASCULAR RISK?
The relationship between blood pressure and risk of cardiovascular disease is linear, continuous, and independent of (though additive to) other risk factors.1 For people 40 to 70 years old, each increment of either 20 mm Hg in systolic blood pressure or 10 mm Hg in diastolic blood pressure doubles the risk of cardiovascular disease across the entire range from 115/75 to 185/115 mm Hg.1 If the patient smokes or has elevated cholesterol, other cardiovascular risk factors, or the metabolic syndrome, the risk is even higher.8
The usual goal of antihypertensive treatment is systolic pressure less than 140 mm Hg and diastolic pressure less than 90 mm Hg. However, the target is lower—less than 130/80 mm Hg—for those with diabetes9 or target organ damage such as heart failure or renal disease.1,10 Thus, it is important to try to detect these conditions in the evaluation of the hypertensive patient.
Another reason it is important is that reducing such risk sometimes calls for using (or avoiding) antihypertensive drugs that are likely to alter these factors. For example, the use of beta-blockers in patients with a low level of high-density lipoprotein cholesterol (HDL-C) can lower HDL-C further.11
DOES THE PATIENT HAVE TARGET ORGAN DAMAGE?
Target organ damage is very important to detect because it changes the goal of treatment from primary prevention of adverse target organ outcomes into the more challenging realm of secondary prevention. For example, if a patient has had a stroke, his or her chance of having another stroke in the next 5 years is about 20%. This is much higher than the risk in an average hypertensive patient without such a history. For such patients, the current guidelines1 recommend the combination of a diuretic and an angiotensin-converting enzyme inhibitor, a combination shown to reduce the risk of a second stroke.12 Thus, we need to discover whether the patient had a stroke in the first place.
HISTORY
- The duration (if known) and severity of the hypertension
- The degree of blood pressure fluctuation
- Concomitant medical conditions, especially cardiovascular or renal problems
- Dietary habits
- Alcohol consumption
- Tobacco use
- Level of physical activity
- A family history of hypertension, renal disease, cardiovascular problems, or diabetes mellitus
- Past medications, with particular attention to their side effects and their efficacy in controlling blood pressure
- Current medications, including over-the-counter preparations. One reason: non-steroidal anti-inflammatory drugs other than aspirin can decrease the efficacy of antihypertensive drugs, presumably through mechanisms that inhibit the effects of vasodilatory and natriuretic prostaglandins and potentiate those of angiotensin II.13
