Automated BP Cuffs, Home Monitoring and Hypertension Definitions

CLINICAL ACTIONS:

The AHA has released a statement on taking BP measurements, a topic also addressed in detail as part of the most recent ACC/AHA task force document. Appropriate preparation is vital to obtaining accurate BP measurements. Following recommended protocols when obtaining a BP measurement can improve accuracy

Prior to Obtaining BP Measurement

  • Ask about the following when taking the family and personal history
    • Medication history (BP and non-BP meds)
      • If patient is on BP meds, is patient currently taking as prescribed
      • If not taking medications appropriately, identify barriers
  • Discuss physical activity and diet
    • If either/both are limited, determine why
  • Caffeine, exercise and smoking should be avoided at least 30 minutes before BP measurement  

When Obtaining BP Measurement

Ensuring the following will prevent artificial increase in BP levels

  • Use correct cuff size
    • Bladder should encircle 80% of the arm
  • Remove clothing covering cuff placement
  • Place and support arm at heart level (atrium / mid-sternum)
  • Ask patient to uncross legs
  • Patient should sit on chair, feet on floor and back supported for > 5 min before taking pressure (not lying or sitting on an exam table)
  • No talking while measurement is taken
  • Have patient empty bladder

SYNOPSIS:

The new ACC/AHA taskforce guidelines have resulted in a change with respect to lowering the threshold for making the diagnosis of hypertension. However, accuracy in obtaining the measurements in critical for accurate management and treatment plan. The AHA has released a scientific statement (2019), maintaining that validated oscillometric devices allow accurate BP measurement in the outpatient setting, while reducing human errors associated with the auscultation. The AHA document further states that

Fully automated oscillometric devices capable of taking multiple readings even without an observer being present may provide a more accurate measurement of BP than auscultation

KEY POINTS:

Hypertension Definitions (ACC/AHA)

  • Normal
    • Systolic <120 mmHg and diastolic <80 mmHg
  • Elevated
    • Systolic 120 to 129 mmHg and diastolic <80 mmHg
  • Hypertension
    • Stage 1: Systolic 130 to 139 mmHg or diastolic 80 to 89 mmHg
    • Stage 2: Systolic ≥140 mmHg or diastolic ≥90 mmHg
  • ‘White Coat’ hypertension
    • Elevated BP in the office but not outside the office
    • Checking for ‘White Coat’ hypertension using either daytime Ambulatory Blood Pressure Monitoring (ABPM) or Home Blood Pressure Monitoring (HBPM) is “reasonable” if
      • Office SBP is >130 but <160 mm Hg or
      • Office diastolic BP (DBP) >80 but <100 mm Hg
  • ‘Masked’ hypertension
    • Elevated BP out-of-office but not in-office
    • Checking for ‘masked’ hypertension with daytime ABPM or HBPM is “reasonable if”
      • Office SPB is 120 to 129 and DBP is <80
  • Acute Severe Hypertension (formerly called ‘malignant hypertension’)
    • SBP ≥180 mmHg or DBP ≥120 mmHg with end organ damage (e.g., pulmonary edema, cardiac ischemia, neurologic deficits, acute renal failure, aortic dissection, and eclampsia is termed hypertensive emergency. This is a medical emergency that requires hospital care)
    • Consider this a medical emergency which may need ICU care
  • Resistant hypertension
    • Uncontrolled BP despite treatment ≥3 antihypertensive agents (one of which is usually a diuretic)

Making the Diagnosis (ACC/AHA)

  • Use an average based on ≥2 readings obtained on ≥2 occasions
  • Out-of-office and self-monitoring can be used to
    • Confirm the diagnosis of hypertension
    • Titrate BP-lowering medication
    • Counsel via Telehealth
  • Corresponding measurements
    • Office/clinic: 140/90
    • HBPM: 135/85
    • ABPM: 135/85
    • Night-time ABPM: 120/70
    • 24-hour ABPM: 130/80 mm Hg
  • In adults with untreated systolic BP (SBP) >130 but 80 but
  • Daytime ABPM or HBPM

Note: The diagnosis of hypertension requires integration of HBPM or ABPM in addition to measurements made in the clinical setting

Learn More – Primary Sources:

Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults – A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines

AHA | AMA: Target BP Tools

Measurement of Blood Pressure in Humans: A Scientific Statement From the American Heart Association

2019 AHA/ACC Clinical Performance and Quality Measures for Adults With High Blood Pressure: A Report of the American College of Cardiology/American Heart Association Task Force on Performance Measures

NEJM Clinical Practice: Acute Severe Hypertension

ACC/AHA Blood Pressure Guideline: Current Classification System and Treatment Targets

SUMMARY:  

The latest USPSTF released its recommendation regarding screening for hypertension in adults (2021). Based on current evidence demonstrating high certainty regarding net benefit, the task force reaffirms and “recommends screening for hypertension in adults 18 years or older with office blood pressure measurement. The USPSTF recommends obtaining blood pressure measurements outside of the clinical setting for diagnostic confirmation before starting treatment. (A recommendation)”.

The ACC/AHA task force report represents the work of several professional bodies based upon hundreds of studies.  There are notable changes from previous practice guidelines, especially related to screening and detection.  The ACC/AHA task force recommends the following classification system:

<120 mmHg and <80 mmHg: NORMAL BP

  • Healthy lifestyle choices  
  • Yearly check-ups 

120 – 129 mmHg and <80 mmHg: ELEVATED BP

  • Healthy lifestyle changes  
  • Reassess in 3 to 6 months  

130 – 139 mmHg or 80-89 mmHg: HIGH BP – STAGE 1  

  • 10-year heart disease and stroke risk assessment <10% risk 
    • Lifestyle changes  
    • Re-assess in 3 to 6 months 
  • 10-year heart disease and stroke risk assessment ≥10% risk 
    • Lifestyle changes  
    • Medication  
    • Monthly follow-up until BP is under control 

≥140 mmHg or ≥90 mmHg: HIGH BP – STAGE 2 

  • Lifestyle changes  
  • Consider initiation of therapy with 2 different classes of medications 
  • Monthly follow-up until BP is under control
  • If BP ≥160/100 mm Hg: Treat promptly, monitor carefully and adjust medication dose upward as necessary to achieve control  

NOTE: Calculate 10-year risk of heart disease or stroke using the ASCVD algorithm published in 2013 ACC/AHA Guideline on the Assessment of Cardiovascular Risk (see ‘Learn More – Primary Sources’ below)

KEY POINTS:  

Risk Factors   

  • Genetic predisposition  
    • Complex polygenic disorder  
    • Rarely single gene disorder (e.g. Liddle’s or Gordon’s syndrome) 
  • Environmental Risk Factors  
    • Overweight and Obesity 
    • Sodium Intake 
    • Potassium  
      • Higher levels appear to blunt sodium effect on BP  
      • Lower sodium/potassium ratio may reduce risk of CVD  
    • Physical fitness  
      • Even modest levels of physical activity is associated with a decrease in the risk of incident hypertension  
    • Alcohol 
      • In US, may account for 10% of BP burden  
      • Also associated with higher HDL and at modest intake range, lower risk for CHD when compared to abstinence 

Non-pharmacological Interventions 

  • Weight loss 
    • Goal: Optimum goal is ideal body weight but can expect 1mm Hg for every 1kg reduction 
  • Diet 
    • DASH diet: Fruits and vegetables, whole grains, low-fat dairy products, reduced saturated and total fat 
    • Other diets with supportive evidence 
      • Low in calories from carbohydrates  
      • High-protein diets  
      • Vegetarian diets  
      • Mediterranean dietary pattern  
    • Sodium: Goal <1500 mg/d, but aim for at least a 1000-mg/d reduction 
    • Potassium: Goal 3500 to 5000 mg/d, preferably through diet 
  • Exercise – Recommend structured exercise program  
    • Aerobic: 90–150 min/wk; 65%–75% heart rate reserve 
    • Dynamic resistance and Isometric resistance also shown to lower BP  
  • Alcohol Reduction (drink = 12 oz regular beer [5% alc] / 5 oz wine [12% alc] / 1.5 oz distilled spirits [40% alc])  
    • Women: ≤ 1 drink per day  
    • Men: ≤ 2 drink per day 

Taking a BP 

  • Prep 
    • Avoid caffeine, exercise, smoking at least 30 minutes before  
    • Empty bladder 
    • No talking while measurement is taken 
    • Remove clothing covering cuff placement 
    • Patient should sit on chair, feet on floor and back supported for > 5 min before taking pressure (not lying or sitting on an exam table) 
  • Technique 
    • Validated device 
    • Support arm 
    • Middle of cuff on upper arm at level of atrium (midpoint of the sternum) 
    • Cuff size: Bladder should encircle 80% of the arm  
    • Can use either stethoscope diaphragm or bell 
  • Taking the measurement 
    • First visit: Record BP in both arms and use arm with higher reading for subsequent measurements  
    • Separate measurement by 1 to 2 minutes 
    • To estimate systolic BP, use radial pulse obliteration and then inflate cuff 20-30 mmHg higher  
    • Deflate cuff pressure 2 mmHg per second and listen for Korotkoff sounds  
      • Systolic BP: First Korotkoff sound 
      • Diastolic BP: Disappearance of all Korotkoff sounds  
      • Use nearest even number  
    • Note time of most recent BP medication before taking measurements  
  • Average the readings to estimate BP 
    • Use average of ≥ 2 readings obtained on ≥ 2 occasions  

Note: The AHA has released a scientific statement that validated oscillometric devices allow accurate BP measurement in the outpatient setting, while reducing human errors associated with the auscultation. The AHA document further states that

Fully automated oscillometric devices capable of taking multiple readings even without an observer being present may provide a more accurate measurement of BP than auscultation. 

Target BP Goal  

  • Known CVD or 10-year heart disease and stroke risk assessment ≥ 10% risk 
    • 130/80 
  • Without additional markers of increased CVD risk, a BP target of less than 130/80 mm Hg may be reasonable 

Adults ≥ 65 years 

  • Treat to same goal of 130/80 as younger adults  
  • Recommendation differs with ACP and AAFP guidance that suggests a goal of 150/90 

Pregnancy Recommendations

  • Women with hypertension who become pregnant, or are planning a pregnancy should be transitioned to methyldopa, nifedipine, and/or labetalol during pregnancy
  • Do not treat women with hypertension in pregnancy with ACE inhibitors, ARBs, or direct renin inhibitors

Oral Contraceptives and NSAIDs

  • Oral contraceptives and NSAIDs are listed as commonly used medications that may cause elevated BP
  • The ACC/AHA guideline recommends the following

 OCPs

Use low-dose (e.g., 20–30 mcg ethinyl estradiol) agents or a progestin-only form of contraception, or consider alternative forms of birth control where appropriate (e.g., barrier, abstinence, IUD)

Avoid use in women with uncontrolled hypertension

NSAIDs

Avoid systemic NSAIDs when possible

Consider alternative analgesics (e.g., acetaminophen, tramadol, topical NSAIDs), depending on indication and risk

Learn More – Primary Sources:

Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults – A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines

Screening for Hypertension in Adults: US Preventive Services Task Force Reaffirmation Recommendation Statement

10-year risk calculator using ASCVD algorithm

AHA AMA: BP Treatment Algorithm 

Measurement of Blood Pressure in Humans: A Scientific Statement From the American Heart Association

2019 AHA/ACC Clinical Performance and Quality Measures for Adults With High Blood Pressure: A Report of the American College of Cardiology/American Heart Association Task Force on Performance Measures