Ambulatory Blood Pressure Monitoring – A New Method for Checking BP
Ambulatory blood pressure monitoring (ABPM) is a non-invasive method used to measure blood pressure at regular intervals over a 24-hour period or longer while patients go about their normal daily activities. It provides a more accurate picture of a patient’s true blood pressure compared to blood pressure measurements taken in a medical setting.
ABPM is an important tool for diagnosing and managing hypertension (high blood pressure). It helps distinguish between white coat hypertension and true hypertension and also help detect masked hypertension.
- White coat hypertension refers to patients who have elevated blood pressure readings in a medical setting but normal readings when measured outside of a clinic.
- Masked hypertension is when a patient’s blood pressure is normal in the hospital but high at some specific times of the day.
When ABPM is Used
There are several situations where ABPM may be recommended:
- To confirm a diagnosis of hypertension if clinic blood pressure readings are elevated
- To identify white coat hypertension or masked hypertension
- To monitor blood pressure control and adjust medications
- To detect abnormal diurnal blood pressure patterns that increase cardiovascular risk
ABPM is also useful for evaluating patients with suspected episodic hypertension (elevated readings that come and go) and hypotension (low blood pressure).
How ABPM Works
During ABPM, a small portable device is worn, usually on a belt around the waist. The device automatically inflates the blood pressure cuff tied around the arm and records blood pressure readings at set intervals – usually every 15-30 minutes during daytime hours and every 30-60 minutes during sleep.
Readings are stored in the device’s memory. After 24 hours, the data is transferred to a computer for analysis by the healthcare provider. The results provide a blood pressure profile over the 24-hour monitoring period.
ABPM vs Clinic Readings
ABPM has several advantages over clinic blood pressure measurements:
- Provides multiple readings over a full day rather than just one or two readings
- Measures blood pressure during normal daily activities and sleep
- Avoids white coat effect where readings are artificially elevated in a clinic setting
- Can assess night-time blood pressure dipping which is important for cardiovascular health
However, ABPM is not routinely recommended for all patients. It may be inappropriate for some patients such as those with atrial fibrillation or other arrhythmias.
Interpreting ABPM Results
Key ABPM parameters that are evaluated include:
- 24-hour average blood pressure
- Daytime (awake) and nighttime (asleep) average pressures
- Blood pressure load – % of readings above normal
- Nocturnal dipping – % drop in nighttime vs daytime pressures
ABPM results are interpreted by a healthcare provider based on established normal values. Abnormal ABPM findings can indicate risks of target organ damage and cardiovascular events if hypertension is not properly treated and controlled.
Treatment Based on Ambulatory Blood Pressure Monitoring
ABPM provides valuable information for hypertension treatment decisions. Based on ABPM results, a provider may:
- Confirm diagnosis and start or change medication if hypertension is not controlled
- Discontinue medication if white coat hypertension is diagnosed and there is no evidence of true hypertension
- Prescribe nighttime doses of medication if nocturnal blood pressure is not dipping properly
- Recommend follow-up ABPM testing to monitor treatment effectiveness
Summary
ABPM is a useful diagnostic and monitoring tool that provides a more complete blood pressure profile to guide clinical decision making in hypertension management.
