Ambulatory blood pressure monitoring (ABPM)

ABPM is a noninvasive technique for measuring multiple BP readings over a 24-hour period during regular activities and during sleep. It has emerged as an increasingly important tool in the diagnosis and management of children with hypertension.

ABPM is performed using an approved ABPM monitor. An appropriately sized BP cuff is placed on the nondominant arm and attached to a small monitor. For 24 hours, BP recordings are taken every 20 minutes while the patient is awake and every 30 minutes while asleep. ABPM is considered satisfactory if there is a minimum of 40 readings during the 24 hours with at least 6 “sleep” readings.

Advantages of ABPM include that measurements are made outside of the healthcare environment and the multiple parameters of BP assessed (mean 24-hour, daytime and night-time SBP and DBP, BP load, nocturnal dipping, and BP variability).

In the general adult population, nocturnal nondipping, nocturnal hypertension, and increased BP variability are predictive of cardiovascular morbidity and mortality. ABPM also permits diagnosis of masked hypertension (normal office BP but ambulatory BP higher than 95th percentile for sex and height). In adults, masked HTN has also been associated with an increase in risk of sustained hypertension and cardiovascular morbidity.

The major pediatric indications for ABPM in children and adolescents are:

• To diagnose white-coat hypertension (multiple providers report elevated office BP readings but BP is normal outside of the clinic setting)
• To diagnose masked HTN
• To confirm normal BP
• To confirm sustained elevation in BP (hypertension)
• To reveal abnormal BP patterns (ie, nocturnal dip or isolated nocturnal HTN)
• To monitor response to treatment

Examples of disorders where ABPM has found use includes diabetes (improved BP control to reduce albuminuria); coarctation of the aorta (rule out masked hypertension); solid organ transplant (rule out masked hypertension); renal transplant recipient (evaluate for nocturnal hypertension); Williams syndrome, Turners syndrome, neurofibromatosis 1, and other syndromes (diagnose, monitor, and help identify patients who require rule-out of RAS).