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.
If secondary hypertension is suspected
A search for secondary forms of hypertension is usually considered in patients with moderate or severe hypertension that does not respond to antihypertensive agents. Another situation is in hypertensive patients younger than 25 years, since curable forms of hypertension are more common in this age group. In older patients, the prevalence of secondary hypertension is lower and does not justify the costs and effort of routine elaborate workups unless there is evidence from the history, physical examination, or routine laboratory work for suspecting its presence. An exception to this rule is the need to exclude atherosclerotic renovascular hypertension in an elderly patient. This cause of secondary hypertension is common in the elderly and may be amenable to therapeutic intervention.26
WHEN TO CONSIDER HOME OR AMBULATORY MONITORING
Suspected white-coat hypertension
Blood pressure can be influenced by an environment such as an office or hospital clinic. This has led to the development of ambulatory blood pressure monitors and more use of self-measurement of blood pressure in the home. Blood pressure readings with these techniques are generally lower than those measured in an office or hospital clinic. These methods make it possible to screen for white-coat hypertension. In 10% to 20% of people with hypertensive readings, the blood pressure may be elevated persistently only in the presence of a physician.28 When measured elsewhere, including at work, the blood pressure is not elevated in those with the white-coat effect. Although this response may become less prominent with repeated measurements, it occasionally persists in the office setting, sometimes for years in our experience.
Suspected nocturnal hypertension (’nondipping’ status)
Ambulatory blood pressure is also helpful to screen for nocturnal hypertension. Evidence is accumulating to suggest that hypertensive patients whose pressure remains relatively high at night (“nondippers,” ie, those with less than a 10% reduction at night compared with daytime blood pressure readings) are at greater risk of cardiovascular morbidity than “dippers” (those whose blood pressure is at least 10% lower at night than during the day).29
An early morning surge
Ambulatory monitoring can also detect morning surges in systolic blood pressure,30 a marker of cerebrovascular risk. Generally, these patients have an increase of more than 55 mm Hg in systolic pressure between their sleeping and early-hour waking values, and we may wish to start or alter treatment specifically to address these high morning systolic values.31
‘PIPESTEM’ VESSELS AND PSEUDOHYPERTENSION
Occasionally, one encounters patients with vessels that are stiff and difficult to compress. If the pressure required to compress the brachial artery and stop audible blood flow with a standard blood pressure cuff is greater than the actual blood pressure within the artery as measured invasively, the condition is called pseudohypertension. The stiffness is thought to be due to calcification of the arterial wall.
A way to check for this condition is to inflate the cuff to at least 30 mm Hg above the palpable systolic pressure and then try to “roll” the brachial or radial artery underneath your fingertips, a procedure known as Osler’s maneuver.32 If you feel something that resembles a stiff tube reminiscent of the stem of a tobacco smoker’s pipe (healthy arteries are not palpable when empty), the patient may have pseudohypertension. However, the specificity of Osler’s maneuver has been questioned, particularly in hospitalized elderly patients.33
Pseudohypertension is important because the patients in whom it occurs, usually the elderly or the chronically ill (with diabetes or chronic kidney disease), are prone to orthostatic or postural hypotension, which may be aggravated by increasing their antihypertensive treatment on the basis of a cuff pressure that is actually much higher than the real blood pressure.33
