Use of ABPM to diagnose hypertension Professor Colin P Bradley Department of General Practice University College Cork

Factors that influence office blood pressure readings Time of day Patient anxiety Patient activity Cuff size Device calibration Medication Recent eating Recent alcohol consumption Caffeine Bladder fullness Smoking

The case for ABPM More data – better information Detection of ‘white coat hypertension’ 20-25% across a range of studies Detection of other abnormalities of blood pressure regulation Masked hypertension Lack of nocturnal dipping Better predictor of cardiovascular outcomes

NICE guideline on diagnosis Hypertension 127 - August 2011 If clinic blood pressure is >140/90 use ABPM (or HBPM) for diagnosis of hypertension If severe hypertension (clinic reading i.e. sys >180 or dia >110) start anti-hypertensive treatment without awaiting ABPM/HBPM Check for end organ damage & assess cardiovascular risk while awaiting result of ABPM ABPM – 2 readings per hour waking; 1 per hour sleeping HBPM – 2 readings each time; record at least twice per day (am &pm) for minimum 4, ideally 7 days (discard first day readings)

NICE Guidelines – evidence base Review question: In adults with suspected primary hypertension, what is the best method to measure blood pressure (HBPM versus ABPM versus CBPM) to predict the development of cardiovascular events?

NICE guidelines – evidence base Review question: In adults with suspected primary hypertension, what is the best method to measure blood pressure (HBPM versus ABPM versus CBPM) to establish the diagnosis of hypertension?

White coat hypertension

Hypertensive -normal dipper pattern

Hypertensive – reverse-dipper

Abnormalities revealed by ABPM White coat hypertension/ white coat effect Masked hypertension Non-dipping Reverse dipping Morning surge

ABPM abnormalities in diabetes Less white coat hypertension More masked hypertension More non-dipping More reverse dipping More morning hypertension (? with diabetic nephropathy)

ABPM thresholds in diabetes Hermida et al 120/70mmHg waking 105/60mmHg asleep Cardoso et. al. mean daytime blood pressure of 125/75mmHg 110/65mmHg for night-time 120/75mmHg for the 24hr mean.

Challenges in ABPM Cost Time Device calibration & maintenance Device failure Patient feasibility &acceptability Interpretation of readings Arrhythmias (esp a. fib) Follow up – are clinic readings ok?