MT Najafi Oct 2014

Introduction

Self-monitoring of blood pressure by patients at home (home blood pressure monitoring (HBPM)) is being increasingly used in many countries and is well accepted by hypertensive patients.

Current hypertension guidelines have endorsed the use of HBPM in clinical practice as a useful adjunct to the conventional office measurements

European Society of Hypertension and European Society of Cardiology Guidelines and the Muted Enthusiasm for Home Blood Pressure Monitoring

The recent, brief summary review, Hypertension Guidelines:(2014)

More Challenges Highlighted by Europe, effectively highlights some weaknesses in the European guidelines for the management of arterial hypertension.

The editors, however, missed an opportunity to restate the importance of home blood pressure monitoring (HBPM).

Measurement of blood pressure outside of the clinic

Measurement of blood pressure outside of the clinic is recognized for providing superior accuracy in predicting future fatal and nonfatal cardiovascular and renal disease.

The gold standard for these predictions is 24-hour ambulatory blood pressure monitoring that measures daytime and nighttime pressures.

Home blood pressure monitoring has rapidly made progress because devices for recording pressures taken at home have improved and become widely available.

Devices for HBPM

Only validated semi-automated or automated oscillometric (electronic) arm cuff devices are recommended.

Devices with memory are preferred.

Auscultatory (aneroid or mercury) devices are not recommended except under specific circumstances (for example, arrhythmia, requiring repeated auscultatory measurements).

Finger cuff devices not recommended.

Wrist cuff devices are not recommended at present, yet possible applications are still under investigation,

as in the case of patients in whom brachial BP measurements are impossible or very difficult (for example, extreme obesity).

Appropriately sized (small, standard or large) cuffs should be used according to arm circumference.

Conditions of measurement

At least 5-min rest, 30 min without smoking, meal, caffeine intake or physical exercise.

Seated position in a quiet room, back supported, arm supported (for example, resting on the table).

Subject immobile, legs uncrossed, not talking and relaxed.

Correct cuff bladder placement at heart level.

Results immediately reported in a specific logbook or stored in device memory

Monitoring schedule

At initial assessment, when assessing treatment effects Seven-day home measurements (minimum 3 days).

Morning (before drug intake if treated) and evening (before eating) readings per day.

Two measurements per occasion (1–2 min apart).

In the long-term follow-up before each clinic/office visit: Less frequent measurements (for example, once or twice per week) could be

regularly performed aimed at reinforcing compliance

Although isolated readings should never be used for diagnostic purposes.

Overuse of the method and self-modification of treatment should be avoided.

Interpretation of home BP readings

Average BP from several monitoring days should be considered

BP values measured on the first monitoring day should be discarded.

Mean home systolic BP>135 mm Hg and/or diastolic BP>85 mm Hg should be considered as elevated.

Systolic and diastolic home BP<130 and<80 mm Hg, respectively, should be considered normal in most subjects.

In high-risk subjects home BP targets should probably be lower.

Indications for HBPM

All patients receiving antihypertensive medication.

To evaluate white-coat hypertension and false uncontrolled hypertension.

To evaluate masked hypertension.

To evaluate resistant hypertension.

To improve compliance with long term treatment.

To improve hypertension control rates.

Conditions where strict blood pressure control is mandatory

(high-risk patients and pregnancy).

Evaluation of Resistant Hypertension

HBPM may be helpful for evaluating resistant hypertension in patients exhibiting high office BP under antihypertensive therapy.

Patients who appear to be refractory to treatment in the office may have adequately controlled home BP

consequently may require less intensification of drug treatment than those whose home BP is also high.

Discrepancies between home and office BP

In the majority of patients, HBPM will lead to the same clinical conclusion regarding the diagnosis of hypertension as the conventional office measurements

Normotension or controlled hypertension if both are normal

Uncontrolled hypertension if both are elevated

However, cases of disagreement in diagnosis between office and home (or ambulatory) BP measurements are not uncommon in both untreated and treated subjects.

Discrepancies between home and office BP

Elevated BP in the office with low home (or ambulatory) BP is known as ‘white-coat’ (or ‘isolated office’) hypertension.

Conversely, normal BP in the office with elevated home (or ambulatory) BP has been termed masked hypertension.

These diagnostic conclusions should be reinforced by performing further investigations including repeated office BP measurements and either a repeated session of HBPM or a 24-h ABPM

Discrepancies between home and office BP

Subjects with white-coat hypertension are at a marginally increased cardiovascular risk and also at an increased risk to develop sustained hypertension.

Therefore, they should be regularly followed using office and home BP measurements.

On the other hand masked hypertension is associated with increased risk of cardiovascular events, similar to that of uncontrolled hypertension.

Given this between-method discrepancy, treatment decisions in white-coat and masked hypertension should probably be made on the basis of both office and out-of-office BP measurements (the latter through ABPM or HBPM, provided that they are reliable and have been repeatedly performed),

Always taking into account the patient’s total cardiovascular risk profile

Need for HBPM in Special Populations

The Elderly

It is well established that the white-coat effect tends to be greater in older than in younger patients.

Because there are also potential hazards of excessive BP reduction in older people, the case for using out-of-office monitoring such as HBPM is very strong.

The difference between the office and home BP (the white-coat effect) increases progressively with age, so that office BP tends to overestimate the out-of-office BP more in older than in younger people.

The variability of systolic home BP readings also increases with age.

HBPM can also be used to detect orthostatic BP changes if readings are taken with the subject both sitting and standing

Patients With Diabetes BP control is one of the most important aspects of managing patients

with diabetes,

and as in patients without diabetes, the home BP is superior to the office BP for predicting the 24-hour BP level.

It is not uncommon for home BP to be elevated (130/80 mm Hg) even when office BP is controlled.

It has been reported that home BP, particularly when measured in the morning, correlates better with target organ damage such as diabetic nephropathy than office BP.

In one study, two thirds of patients with normal office BP had elevated home BP in the morning hours

The International Diabetes Federation has advocated its use, but the American Diabetes Association has remained silent on this issue

Pregnancy The accurate measurement of BP during pregnancy is one of the most

important aspects of prenatal care,

Preeclampsia, which is the most common cause of maternal and fetal death, can develop quite rapidly.

The situation in pregnancy is essentially dynamic: BP first falls and then rises

Therefore the best way of detecting an abnormal pattern that presages preeclampsia may be to monitor its changes very frequently throughout the course of pregnancy.

Thus, the earliest manifestation of preeclampsia is a failure to decrease BP, or a premature increase of BP, during the second trimester.

HBPM is theoretically ideal for monitoring changes in BP during pregnancy because it is the best technique for providing multiple readings recorded at the same time of day over prolonged periods of time.

White-coat hypertension is not uncommon and may lead to unnecessary early termination of pregnancy.

This should be detectable with the use of HBPM.

Chronic Kidney Disease

Hypertension is highly prevalent in patients with chronic kidney disease and also in the dialysis population, but the BP is very variable, and measurements made in dialysis centers provide a poor prediction of clinical outcomes.

HBPM has been advocated in these patients but thus far has been used infrequently.

Despite the fact that arterial stiffness is greatly increased in such patients, oscillometric monitors may still be accurate in patients with end-stage renal disease.

HBPM has been shown to be superior to measurements made in the dialysis unit for predicting ambulatory hypertension

Summary of advantages and limitations of HBPM

Advantages A number of measurements of blood pressure and heart rate during

the day and also over several days, weeks or months are possible.

Assessment of treatment effects at different times of the day and over extended periods.

No alarm (white-coat) reaction to blood pressure measurement.

Diagnosis of white-coat and masked hypertension.

Good reproducibility.

Good prognostic value.

Relatively low cost.

Advantages

Patient-acceptance.

Education tool—involvement of patients in hypertension management.

Possibility of digital storage, printout, PC download or teletransmission of blood pressure values (some devices).

Improvement of patients’ compliance to drug treatment.

Improvement of hypertension control rates.

Limitations

Need of patient training (simple for automated devices).

Possible use of inaccurate devices.

Measurement errors.

Questionable reliability of blood pressure values reported by patients.

Induction of anxiety, resulting in excessive monitoring.

Risk of treatment changes made by patients on the basis of casual home measurements without doctor’s guidance.

Normality thresholds and therapeutic targets still debated, mainly in patients at high cardiovascular risk.

Lack of night-time recordings

Absence of reimbursement by insurance company or social security in most countries.

Telemedicine

The advantages for this strategy are that pressures can be recorded during many days, weeks, and months.

The newer devices can send results to a data center or individual care providers for review and management.

In this sense, telemedicine has arrived for care of hypertension and seems to have made a successful landing.

With the increasing need for primary care physicians, especially in the United States, telemedicine for hypertension may become a valuable alternative for management of hypertension

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