Definition
Ambulatory Blood Pressure Monitoring (ABPM) provides an accurate and reliable measurement of blood pressure throughout the day and night, thus providing valuable diagnostic information beyond what is routinely provided in-clinic or with home blood pressure monitoring.
ABPM can help monitor:
- True blood pressure during day-to-day activities – helps diagnose ‘white coat’ hypertension
- How much blood pressure falls during sleep – dipper status
- Morning surges in blood pressure
- Total burden of hypertension
Why the test is performed
ABPM is a valuable tool for diagnosing and managing multiple conditions:
- “White coat” hypertension: When elevated blood pressure measurements are recorded in the physician’s office, but blood pressure readings outside the physician’s office are within the normal range. It is estimated that one in three patients with high blood pressures might have white coat hypertension.
- Resistant hypertension: When multiple anti-hypertensive medications fail to adequately control high blood pressure.
- Masked hypertension: When in-office measurements fall within an acceptable range, but the mean blood pressure is actually above the acceptable range.
- Hypotension: Sometimes hypertensive therapy can be associated with low blood pressures. This can be dangerous, particularly in patients with diabetes or with a history of stroke. Ambulatory monitoring can detect asymptomatic drops in blood pressure.
- Diagnosing nocturnal non-dipper status: Healthy individual’s systolic blood pressures drop at least 10% while they sleep as compared to systolic blood pressures during the day. Individuals who are non-dippers, whose blood pressure does not drop, are at increased risk of cardiovascular events.
Risks
There are no serious risks from ambulatory blood pressure monitoring. Minor side effects reported include pain or discomfort (9%), skin irritation (8%), noisy device (8%) and inconvenience with work (3%). A minority of patients report interference with sleep. However, vast majority of patients get accustomed to the monitor.
How the test is performed
The diagnostic test begins with fitting a patient with a portable monitor and BP cuff. The patient leaves and returns the next day. Over this period of time, the monitor takes measurements periodically as programmed by the clinician. This generally happens every 15-30 minutes while awake and 30-45 minutes while sleeping.
After the test
When the patient returns, these measurements are transferred to a computer where they can be easily viewed and documented in a report.
Outlook (Prognosis)
The results of ambulatory blood pressure testing provide the most comprehensive representation of a patient’s complete blood pressure profile.