From the Guidelines
A 24-hour blood pressure monitor is indicated for clinical scenarios such as suspected white-coat hypertension, apparent drug resistance, hypotensive symptoms with antihypertensive medication, episodic hypertension, and autonomic dysfunction, as outlined in the seventh report of the joint national committee on prevention, detection, evaluation, and treatment of high blood pressure 1. These indications are crucial because ambulatory blood pressure monitoring (ABPM) provides a more accurate representation of a patient's blood pressure profile compared to office readings.
- Key scenarios where ABPM is helpful include:
- Suspected white-coat hypertension in patients with hypertension and no target organ damage
- Apparent drug resistance (office resistance)
- Hypotensive symptoms with antihypertensive medication
- Episodic hypertension
- Autonomic dysfunction ABPM values are typically lower than clinic readings, with awake hypertensive individuals having an average BP of 135/85 mm Hg and during sleep, 120/75 mm Hg, as reported in the study 1. The level of BP measurement using ABPM correlates better with target organ injury than office measurements, and it also provides a measure of the percentage of BP readings that are elevated, the overall BP load, and the extent of BP fall during sleep 1. The use of ABPM is supported by evidence showing that patients whose 24-hour BP exceeded 135/85 mm Hg were nearly twice as likely to have a cardiovascular event as those with 24-hour mean BPs less than 135/85 mm Hg, irrespective of the level of the office BP 1.
From the Research
Indications for 24 Hour BP Monitor
The following are indications for 24 hour BP monitor:
- Diagnosis of white coat hypertension, which is common in referred hypertensive patients 2
- Identification of masked hypertension or excessive BP reduction 3
- Assessment of early-morning hypertension and excessive BP variability, both of which correlate with target-organ damage and cardiovascular outcomes 3
- Evaluation of the effectiveness of antihypertensive treatment and identification of patients who may require more aggressive therapy 3
- Detection of autonomic nervous system dysregulation in patients with white coat hypertension 4
- Monitoring of patients with obstructive sleep apnea, as they are at increased risk of developing sustained hypertension 5
Patient Groups that Benefit from 24 Hour BP Monitoring
The following patient groups may benefit from 24 hour BP monitoring:
- Patients with suspected or treated hypertension 6
- Patients with white coat hypertension or masked hypertension 2, 6
- Patients with obstructive sleep apnea 5
- Patients at risk of cardiovascular events 3
- Patients with autonomic nervous system dysregulation 4
Key Findings
Some key findings related to 24 hour BP monitoring include:
- Elevation of BP above 140 mm Hg systolic or 90 mm Hg diastolic in the first or last hour of monitoring diagnoses patients with a white coat response in whom there is a higher BP profile than in patients with classic white coat response alone 2
- ABPM data can identify early-morning hypertension and excessive BP variability, both of which correlate with target-organ damage and cardiovascular outcomes 3
- White coat hypertension assessed by home measurements is a cardiovascular risk factor in untreated but not in treated subjects 6
- Masked uncontrolled hypertension is associated with increased cardiovascular risk in both untreated and treated patients 6