Diagnostic Criteria for Hypertension

How Blood Pressure is Measured for Diagnosis

• Out-of-office measurements (HBPM or ABPM), or
• At least one additional subsequent office measurement

• Office BP (OBP) — clinic/office sphygmomanometry
• Home Blood Pressure Monitoring (HBPM) — patient self-measurement
• Ambulatory Blood Pressure Monitoring (ABPM) — 24-hour automated recording

BP Classification Table

ACC/AHA 2017 Classification (North American Standard)

Key difference: ACC/AHA 2017 defines hypertension at ≥130/80 mmHg, while ESC and most international guidelines retain the traditional ≥140/90 mmHg office threshold.

Treatment Thresholds (ACC/AHA 2017)

• High ASCVD risk patients (10-year risk ≥10%, CKD, diabetes): target <130/80 mmHg
• Lower-risk patients: strongest clinical trial evidence supports target <140/90 mmHg
• Age >80 years: individualized targets; aggressive lowering carries higher risk

Special Considerations

Key Diagnostic Principles

1. Two or more readings on two or more occasions are needed before diagnosis
2. Measure in both arms — use the arm with the higher reading
3. Patient should be seated, rested ≥5 minutes, no caffeine/smoking for 30 minutes
4. ABPM is the gold standard for confirming diagnosis and identifying white coat or masked hypertension
5. Secondary causes should be excluded, especially in young patients, resistant hypertension, or sudden onset

Complications of Hypertension

1. Cardiac Complications

2. Cerebrovascular Complications

3. Renal Complications

4. Vascular Complications

5. Retinal Complications (Hypertensive Retinopathy)

6. Hypertensive Emergencies (Acute Severe Complications)

• Hypertensive encephalopathy
• Acute pulmonary edema / flash pulmonary edema
• Acute MI or unstable angina
• Acute aortic dissection
• Acute kidney injury (AKI)
• Eclampsia (in pregnancy)

Summary: Organ-wise Complication Overview

Hypertension
├── Heart → LVH, HF, CHD, AF
├── Brain → Stroke (ischemic/hemorrhagic), dementia, encephalopathy
├── Kidneys → CKD, proteinuria, ESRD
├── Vessels → PAD, aortic aneurysm, dissection
└── Eyes → Hypertensive retinopathy (Grades I–IV)

Hypertension doubles the risk of coronary heart disease, congestive heart failure, ischemic and hemorrhagic stroke, renal failure, and peripheral arterial disease. (Harrison's 21st ed., p. 7631)

Diagnostic Methods for Hypertension

1. Blood Pressure Measurement Techniques

A. Office / Clinic BP (OBP)

• Patient seated, rested ≥5 minutes; no caffeine/smoking for 30 minutes
• Arm supported at heart level; appropriate cuff size mandatory
• Average of ≥2 readings on ≥2 separate visits
• Measure both arms — use the higher reading arm consistently
• Check standing BP in elderly/diabetics to detect orthostatic hypotension

B. Ambulatory Blood Pressure Monitoring (ABPM) — Gold Standard

• 24-hour automated readings every 15–30 minutes (day and night)
• Best for diagnosing white coat and masked hypertension
• Provides nocturnal dipping data (non-dipping pattern = higher CV risk)
• Recommended by VA/DoD, USPSTF 2015, and AHA/ACC 2017 to confirm diagnosis before initiating drug therapy (Diagnosis and Management of HTN in Primary Care, p. 31)

C. Home Blood Pressure Monitoring (HBPM)

• Patient self-measures morning and evening over 7 days
• Average of readings (discarding day 1) used for diagnosis
• More accessible than ABPM; requires patient training
• Useful for detecting masked HTN and monitoring treatment response

2. Routine Laboratory Investigations

3. Electrocardiogram (ECG)

• First-line cardiac investigation in all hypertensive patients
• Detects Left Ventricular Hypertrophy (LVH):
  • Sokolow-Lyon criteria: S in V1 + R in V5/V6 >35 mm
  • Cornell criteria: R in aVL + S in V3 >28 mm (men) / >20 mm (women)
• ST depression and T-wave inversion = LV strain pattern (advanced hypertensive heart disease)
• Detects arrhythmias (e.g., atrial fibrillation), conduction defects, prior MI

4. Echocardiography

• Detects LVH more sensitively than ECG
• Assesses left ventricular mass index (LVMI), geometry (concentric vs. eccentric)
• Evaluates diastolic dysfunction (early hypertensive heart disease)
• Measures ejection fraction; detects valvular disease
• Indicated when ECG is abnormal or symptoms of HF are present

5. Imaging Studies

6. Investigations for Secondary Hypertension

Diagnostic Approach Summary

Elevated Office BP (≥140/90 mmHg)
        ↓
Confirm with ABPM or HBPM
        ↓
Routine labs + ECG + fundoscopy
        ↓
Assess target organ damage (Echo, renal function, urine albumin)
        ↓
Screen for secondary causes if clinically indicated
        ↓
Cardiovascular risk stratification → guide treatment threshold

Hypertension vs. Hypertonia

Hypertension

• Elevation of systemic arterial BP (≥140/90 mmHg by ESC; ≥130/80 mmHg by ACC/AHA)
• Caused by increased cardiac output, increased peripheral vascular resistance, or both
• Complications: stroke, MI, heart failure, CKD, retinopathy (as covered above)

Hypertonia

• Increased resistance to passive movement of a muscle or limb
• Results from upper motor neuron (UMN) lesions disrupting descending inhibitory pathways
• Two main subtypes:

The "Hyper-" Confusion — Quick Reference