The current guidelines from the American College of Cardiology recommend close home monitoring of blood pressure by patients. Why is this? We are reluctant to diagnose a patient with hypertension based on only one or two readings obtained during an office visit. So many factors can immediately influence blood pressure, including sleep, stress, diet, alcohol consumption, and timing of medications. As these factors vary day-to-day, so will the blood pressure. Ultimately, it is important that the average blood pressures are at goal, even if there are some high and low readings.
In the office, we might see people with white coat hypertension. This is when blood pressure is well-controlled at home but elevated in the office. This is often associated with anxiety from visiting the doctor, but might also be due to the stress of driving to the office or even the frustrating procedures to get checked-in.
We might also see patients with masked hypertension. This is when blood pressures are well controlled in the office but elevated at home. For instance, if every visit with a particular patient occurs a couple of hours after he takes his morning blood pressure medications, his blood pressure may look perfect in the office. We would be missing readings early in the morning or later in the evening when blood pressure might be elevated.
What Are Current Definitions of High Blood Pressure?
The definition of high blood pressure has been a moving target over the years, leading to much confusion among both patients and healthcare professionals. In fact, there continue to be a number of guidelines published by various organizations with conflicting definitions and recommendations on treatment. The most current set of guidelines followed by Cardiologists was published in 2017 and was agreed upon by a joint task force including both the American College of Cardiology and the American Heart Association.
- Normal BP: < 120/< 80 mmHg
- Elevated BP: 120-129/< 80 mmHg
- Hypertension, Stage I: 130-139/80-89 mmHg
- Hypertension, Stage II: >140/> 90 mmHg
In order to determine blood pressure, an average of at least 2 readings should be obtained on at least 2 separate occasions. Self-monitoring of blood pressure at home is recommended to confirm the diagnosis.
Here are some guidelines from the American College of Cardiology which review the appropriate way to check blood pressure at home, and some non-medication interventions which may help to reduce blood pressure.
Table 10: Procedures For Use of HBPM (Home Blood Pressure Monitoring)
|Patient training should occur under medical supervision, including:|
▪ Information about hypertension
▪ Selection of equipment
▪ Acknowledgment that individual BP readings may vary substantially
▪ Interpretation of results
▪ Verify use of automated validated devices. Use of auscultatory devices (mercury, aneroid, or other) is not generally useful for HBPM because patients rarely master the technique required for measurement of BP with auscultatory devices.
▪ Monitors with provision for storage of readings in memory are preferred.
▪ Verify use of appropriate cuff size to fit the arm.
▪ Verify that left/right inter-arm differences are insignificant. If differences are significant, instruct patient to measure BPs in the arm with higher readings.
Instructions on HBPM procedures:
▪ Avoid smoking, caffeinated beverages, or exercise within 30 min before BP measurements.▪ Ensure ≥5 min of quiet rest before BP measurements.
▪ Sit with back straight and supported (on a straight-backed dining chair, for example, rather than a sofa).
▪ Sit with feet flat on the floor and legs uncrossed.
▪ Keep arm supported on a flat surface (such as a table), with the upper arm at heart level.
▪ Bottom of the cuff should be placed directly above the antecubital fossa (bend of the elbow).
Take multiple readings:
▪ Take at least 2 readings 1 min apart in the morning before taking medications and in evening before supper. Optimally, measure and record BP daily. Ideally, obtain weekly BP readings beginning 2 weeks after a change in the treatment regimen and during the week before a clinic visit.
Record all readings accurately:
▪ Monitors with built-in memory should be brought to all clinic appointments.
▪ BP should be based on an average of readings on ≥2 occasions for clinical decision making.
Table 15: Best Proven Non-pharmacological Interventions for Prevention and Treatment of Hypertension
When Should High Blood Pressure Be Treated with Medications?
In patients who fail to achieve blood pressure goals with lifestyle changes alone, medications may be indicated. In general, they are recommended in the following situations:
- In patients with CVD: SBP > 130 mmHg or DBP > 80 mmHg
- In patients with no CVD but estimated 10-year risk > 10%: SBP > 130 mmHg or DBP > 80 mmHg
- In patients with no CVD, estimated 10-year risk < 10%: SBP > 140 mmHg or DBP > 90 mmHg
** CVD — Cardiovascular Disease, Estimated 10-year risk determined by the Pooled Cohort Risk Assessment Equation
What is the Goal Blood Pressure When Treated with Medications?
- Known CVD or 10-year risk > 10%: <130/80 mmHg
- HTN without CVD or elevated 10-year risk: <130/80 mmHg