Hypertension Grading
Blood pressure should be categorized using either the ACC/AHA or ESC/ESH classification systems, with the ACC/AHA defining hypertension at ≥130/80 mmHg (stages 1-2) and the ESC/ESH defining it at ≥140/90 mmHg (grades 1-3). 1
ACC/AHA Classification (2017)
The American College of Cardiology and American Heart Association categorize blood pressure into four levels based on office measurements: 1
- Normal BP: <120/<80 mmHg 1
- Elevated BP: 120-129/<80 mmHg (systolic elevated but diastolic remains normal) 1
- Stage 1 Hypertension: 130-139/80-89 mmHg 1
- Stage 2 Hypertension: ≥140/≥90 mmHg 1
When systolic and diastolic values fall into different categories, always classify the patient according to the higher category. 1 This classification represents a significant departure from JNC 7, lowering the hypertension threshold from 140/90 to 130/80 mmHg. 1
ESC/ESH Classification (2018)
The European Society of Cardiology and European Society of Hypertension use a more granular six-category system: 1
- Optimal BP: <120/<80 mmHg 1
- Normal BP: 120-129/80-84 mmHg 1
- High Normal BP: 130-139/85-89 mmHg 1
- Grade 1 Hypertension: 140-159/90-99 mmHg 1
- Grade 2 Hypertension: 160-179/100-109 mmHg 1
- Grade 3 Hypertension: ≥180/≥110 mmHg 1
- Isolated Systolic Hypertension: ≥140/<90 mmHg 1
Critical Measurement Requirements
Base your classification on the average of ≥2 careful readings obtained on ≥2 separate occasions, with the patient seated quietly for at least 5 minutes. 1 Both guidelines strongly emphasize: 1
- Use only validated BP measurement devices 1
- Confirm office hypertension with out-of-office measurements (home or ambulatory monitoring) to exclude white coat hypertension 1
- Take 3 readings for office BP, with additional readings if the first 2 differ by >10 mmHg 1
Key Differences Between Guidelines
The fundamental divergence is the diagnostic threshold: ACC/AHA defines hypertension at ≥130/80 mmHg while ESC/ESH maintains ≥140/90 mmHg. 1, 2 This difference has substantial population impact—the ACC/AHA classification increased U.S. hypertension prevalence from 32% to 46%, though it only increased those requiring pharmacological therapy by 1.9%. 1, 2
The ESC/ESH uniquely recognizes isolated systolic hypertension as a distinct category (≥140/<90 mmHg), which is particularly important in elderly patients where this represents the dominant hypertensive pattern. 1, 3
Prognostic Considerations
Grade 3/Stage 2 hypertension (≥180/≥110 mmHg) carries significantly higher cardiovascular risk than lower grades. 4 Recent evidence shows that while cardiovascular event rates differ between Grade 1 and Grade 2 in the ESC/ESH system, the difference is not statistically significant after adjustment for covariables. 4 However, Grade 3 hypertension demonstrates a clearly elevated risk (1.93 events per 100 patient-years vs 0.73-0.95 for Grades 1-2), though this excess risk is largely explained by higher 24-hour ambulatory BP levels. 4
Special Populations
In elderly patients with isolated systolic hypertension, target systolic BP <140 mmHg while maintaining diastolic BP ≥70 mmHg to prevent tissue hypoperfusion. 3 The association of elevated systolic BP with low diastolic BP (60-70 mmHg) represents additional cardiovascular risk. 2
Hypertensive Crisis
Hypertensive crisis is defined as systolic BP >180 mmHg or diastolic BP >120 mmHg, requiring immediate evaluation for end-organ damage. 5 This represents a medical emergency when acute end-organ damage is present (hypertensive emergency) versus urgency when minimal or no end-organ damage exists. 5