NIHR Bart’s and The London Cardiovascular Biomedical Research Unit
William Harvey Research Institute
ABPM Interpretation & Hard To Manage BP
Dr Mel Lobo PhD FRCP Director Barts Blood Pressure Clinic Bart’s Health NHS Trust NIHR Barts Cardiovascular Biomedical Research Unit William Harvey Research Institute, QMUL
CONVENTIONAL BP MEASUREMENT LOCATION
SPHYGMOMANOMETER
TEMPERATURE
HEIGHT
HUMIDITY
POSITION & TILT
NOISE
LEVEL OF HG
OBSERVER BIAS
MAINTENANCE STETHOSCOPE
DIGIT PREFERENCE INATTENTION RAPPORT
SUBJECT
HEARING & VISION
ANXIETY
DISTANCE
RECENT EXERCISE MEAL OR TOBACCO
OBESITY CUFF/BLADDER CUFF CONDITION APPLICATION BLADDER SIZE BLADDER POSITION RIGHT OR LEFT?
ELDERLY ARRHYTHMIA POSTURE ARM LEVEL
ARM SUPPORT
BP MEASUREMENT: KEY TECHNIQUES BP (mm Hg) if not done Rest ≥ 5 min, quiet Seated, back supported
↑ 12/6 ↑ 6/8
Cuff at midsternal level
↑ ↓ 2/inch
Correct cuff size (undercuffing)
↑ 6-18/4-13
Bladder center over artery Deflate 2 mm Hg/sec
↑ 3-5/2-3 ↑ SBP/↓ DBP
If initial BP > goal BP:
1st reading higher
3 readings, 1 min apart
“Alerting response”
Discard 1st, average last 2 Hypertension 2005; 45:142
J Hypertens 2005; 23:697
Can J Card 2007; 23:529
NICE 2011 Diagnosis of hypertension (1) If the clinic blood pressure is 140/90 mmHg or higher, offer ambulatory blood pressure monitoring (ABPM) to confirm the diagnosis of hypertension. Evidence ABPM is superior to clinic blood pressure and in most studies home blood pressure monitoring for diagnosis ABPM is gold standard – HBPM is a less good alternative if not available or possible
NICE 2011 Diagnosis of Hypertension(2) When using the following to confirm diagnosis, ensure: ABPM: – at least two measurements per hour during the person’s usual waking hours, average of at least 14 measurements to confirm diagnosis HBPM: – two consecutive seated measurements, at least 1 minute apart – blood pressure is recorded twice a day for at least 4 days and preferably for a week – measurements on the first day are discarded – average value of all remaining is used.
Definitions Stage 1 hypertension: • Clinic blood pressure (BP) is 140/90 mmHg or higher and • ABPM or HBPM average is 135/85 mmHg or higher.
Stage 2 hypertension: • Clinic BP 160/100 mmHg is or higher and • ABPM or HBPM daytime average is 150/95 mmHg or higher.
Severe hypertension: • Clinic BP is 180 mmHg or higher or • Clinic diastolic BP is 110 mmHg or higher.
ABPM – the origins...
ABPM 2012
Case examples
Standard ABPM report – normal BP result
Daytime Mean 128/78 mm Hg Nocturnal Mean 110/62 mm Hg
White COAT HYPERTENSION 20 -25% hypertensive population OBP Initial ABPM reading Daytime Mean Nocturnal Mean
156/88 mm Hg 205/100 mm Hg 128/68 mm Hg 112/54 mm Hg
The ABPM shows marked white-coat hypertension (205/100 mmHg) with otherwise normal 24-hour systolic & diastolic blood pressure (128/68 mmHg daytime and 112/54 mmHg night-time).
Standardising ABPM reporting Report (requires 14 day time readings to be completed)
• • • • •
Record name of patient and date of study Daytime Mean and heart rate then night time mean and heart rate Comment on presence/absence of nocturnal dipping Presence/absence of white coat effect (note the highest WC BP) Comment on BP variability (SD of mean)
•
The 24 hr ABPM on Mr XX was done on 1.8.2014 and showed a daytime mean of 132/78 mm Hg with a heart rate of 85 bpm. There was well preserved nocturnal dipping to an ideal mean of 119/72 mm Hg with HR of 65 bpm. There was pronounced white coat effect with an initial reading of 178/105 mm Hg. The study demonstrated physiological variability of ABP and DBP during the day and night. Conclusion – this study demonstrates white coat hypertension with high resting HR
•
A few words about hard to manage BP
Global definitions of RHTN
Messerli and Bangalore. European Heart Journal (2013) 34;1175-1177
Epidemiology of Resistant Hypertension • Incidence of resistant hypertension is 0.7 per 100 patient years Daugherty SL et al., Circulation 2012; 125: 1635-1642
• Estimated prevalence rates are varied Due to different definitions of resistant hypertension Up to 35% in post-hoc analyses of major outcome trials (LIFE, ALLHAT, ASCOT) 8-20% in cohort studies Daugherty SL et al., Circulation 2012; 125: 1635-1642 de la Sierra A et al., Hypertension 2011; 57: 898-902 Persell SD, Hypertension 2011; 57: 1076-1080
Epidemiology of Hypertension in the UK £1 billion/pa direct drug costs 12% of all primary care consultations are regarding HTN 12 million hypertensive adults in the UK 8 million are diagnosed 7 million are treated 4 million are treated 75 yrs Females Black ethnicity Higher baseline BP and chronic uncontrolled HTN Diabetes Obesity Atherosclerotic vascular disease and aortic stiffening Existing target organ damage: LVH, CKD, retinopathy Excessive salt intake
Factors associated with Pseudo- Resistant Hypertension Physician-related Inappropriate BP measurement Under-cuffing Use of automated methods in arrhythmias Lack of ABP to r/o WCH Physician inertia Inappropriate medication classes/doses Suboptimal consultations
Patient-related White coat effect Non-adherence to therapy Poor concordance Medication intolerance Lifestyle issues Costs of drugs
Clinic reading 168/92 mm Hg Daytime Mean 117/77 mm Hg
Myat et al. BMJ 2012;345:e7473
Investigation for secondary causes
• Investigate pts with resistant hypertension for secondary causes
• Choices of investigation modalities used to be very much centre-oriented – less so now • Detailed assessment is best undertaken in dedicated specialist centres (BHS Hypertension Centres of Excellence)
Medical treatment strategies (1) Effect for lifestyle interventions Intervention
