HYPERTENSION

Casual Office Blood Pressure Blood pressure is normally distributed within the population, with no natural cutoff point allowing discrimination between normotensive and hypertensive individuals. Moreover, the tendency for blood pressure to rise with age makes it difficult to apply uniformly any criteria of normal blood pressure. In women the blood pressure rise is steeper after menopause.The definition of hypertension is in some way arbitrary. By choosing specific blood pressure levels as upper limits of normal it is meant that the cardiovascular risk becomes high enough to warrant an intervention. Most socalled hypertensive individuals have only slightly elevated blood pressures. Even small blood pressure reductions in these hypertensives are associated, in terms of public health, with a substantial reduction in cardiovascular morbidity and mortality. The proposed definitions of normo- and hypertension proposed by major guidelines are very similar.192–196Table 86.8 gives as an example the definitions proposed by the Joint National Committee on Prevention, Detection,Evaluation, and Treatment of High Blood Pressure in the U.S.A. (JNC 7 Report).The key point is that a blood pressure 140 mm Hg for systolic and/or ≥90 mm Hg for diastolic has to be considered as abnormally elevated. Isolated systolic hypertension is defined as a systolic blood pressure ≥140 mm Hg together with a diastolic blood pressure <90 mm Hg. Individuals with blood pressures at the upper range of normalcy should be followed regularly and be advised to initiate lifestyle modifications. The definitive diagnosis of hypertension should be based on repeated blood pressure measurements on different occasions. The goal of treatmentis to bring blood pressure below 140/90 mm Hg using lifestyle measures together with pharmacologic treatment when needed. Strict blood pressure control (<130/80 mm Hg) is required in patients with diabetes or chronic renal disease. Lower targets are even desirable if proteinuria is >1 g/day.

 Noninvasive Ambulatory Blood Pressure in hypertension

Monitoring Blood pressures recorded during everyday activities away from the medical setting are usually lower than casual office blood pressures.198 Target-organ damage is more closely associated with ambulatory blood pressures than conventional casual blood pressures, as a consequence mainly of the large number of blood pressure readings made available by ambulatory recordings.226 Nighttime blood pressure is normally lower than daytime blood pressure. The lack of a normal nocturnal decline in blood pressure may be seen in patients with essential hypertension, but is observed particularly in patients with secondary forms of hypertension, in preeclampsic women, in patients with sleep apnea syndrome, and in diabetics with peripheral neuropathy. A blunted day–night fall in blood pressure seems to be harmful. An extreme nocturnal dipping, however, may represent an increased risk of stroke. Table 86.9 shows the normal ranges that are currently proposed. There is still no firm consensus on the use of noninvasive blood pressure monitoring. This technique allows the detection of patients with white-coat hypertension, that is, patients whose blood pressures are high only in a medical setting.227 White-coat hypertension is encountered commonly, in approximately 20% of mild hyper tensives. In general, target-organ damage in white-coat hypertension is less prevalent than that in sustained hypertension. Patients with white-coat hypertension, however, seem to have a higher cardiovascular risk than do normotensives. They should be advised to initiate lifestyle changes and followed regularly as they are prone to develop sustained hypertension.The main indications for ambulatory blood pressure monitoring are considerable variability of office blood pressure, high office blood pressure in patients with low global cardiovascular risk, treatment-resistant hypertension, and the presence of symptoms possibly attributable to hypo- or hypertension.

Self-Measurement of Blood Pressure in hypertension

Self-monitoring of blood pressure by patients at home has become increasingly popular in recent years, in parallel with the exploding availability of electronic, easy to use, and affordable blood pressure measuring devices.228 Home blood pressures are usually lower than office blood pressures and have a better prognostic significance than blood pressure obtained in a clinical setting. The value of 135/85 mm Hg may be considered as the upper limit of normality. Training of patients is essential to obtain reliable blood pressure readings. Patients should measure their blood pressure at home twice in the morning and twice in the evening for at 3 working days if a therapeutic decision has to be taken. Self–blood pressure monitoring is particularly helpful to detect white-coat hypertension, to guide antihypertensive therapy, and to improve the patient’s compliance with antihypertensive therapy.