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Hypertension

Definition and Classification

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Epidemiology

• Affects approximately 1.3 billion adults worldwide, with prevalence rising with age - up to 70% of older adults in the United States have hypertension.
• Non-Hispanic Black adults have disproportionately high prevalence, earlier onset, and higher rates of CVD and kidney disease from hypertension, compared to white or other race/ethnicity groups.
• BP control rates remain suboptimal: in the 2017-2020 NHANES survey, only 52% of White and 37% of Black adults with hypertension were controlled to <140/90 mmHg.

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Types: Primary vs. Secondary

Primary (Essential) Hypertension (~95% of cases)

• Dietary: excess sodium intake, insufficient potassium intake, poor diet quality
• Lifestyle: physical inactivity, obesity (BMI ≥30), excess alcohol
• Environmental: heavy metal exposure (lead, cadmium, arsenic), air pollution (PM2.5 raises SBP by ~3-5 mmHg), seasonal cold temperature, high altitude
• Psychosocial: chronic stress

Secondary Hypertension (~5% of cases)

1. Treatment-resistant hypertension
2. Abrupt worsening of previously controlled hypertension
3. Disproportionate target organ damage
4. Lab findings: unprovoked hypokalemia, proteinuria, left ventricular hypertrophy

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Pathophysiology

1. Renin-Angiotensin-Aldosterone System (RAAS) activation: Increased angiotensin II causes vasoconstriction and aldosterone-mediated sodium/water retention, raising both vascular resistance and volume.
2. Sympathetic nervous system overactivity: Increases heart rate, cardiac output, and vasoconstriction.
3. Impaired endothelium-dependent vasorelaxation: Reduced nitric oxide (NO) bioavailability decreases vasodilation.
4. Sodium retention: Abnormal renal sodium handling raises intravascular volume.
5. Vascular remodeling: Structural changes in vessel walls increase peripheral vascular resistance chronically.

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Target Organ Damage

Hypertensive Retinopathy (Target Organ Damage - Eye)

• Mild: Generalized/focal arteriolar narrowing, AV nicking (compressed veins at arteriovenous crossings)
• Moderate: Retinal hemorrhages, hard exudates (lipid deposits), cotton wool spots (nerve fiber infarcts)
• Severe: Papilledema (hypertensive emergency)

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Measurement

• Use appropriate cuff size; arm at heart level; patient seated and rested ≥5 minutes
• Measure in both arms initially; use the higher reading
• White coat hypertension: BP elevated in office only - confirmed with ambulatory BP monitoring (ABPM) or home BP monitoring
• Masked hypertension: Normal in office, elevated at home - higher CVD risk than white coat
• ABPM is the gold standard for diagnosis and is recommended when office readings are uncertain

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Non-Pharmacologic Management (Lifestyle Modifications)

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Pharmacologic Management

When to Start

• Stage 1 (130-139/80-89): Start if ASCVD risk ≥10% or existing CVD/diabetes/CKD; otherwise lifestyle first
• Stage 2 (≥140/90): Start medication along with lifestyle changes
• Most patients require 2 or more agents

First-Line Drug Classes

Compelling Indications Guide Drug Selection

BP Targets

• General: < 130/80 mmHg (ACC/AHA) or < 140/90 mmHg (ESC/ESH)
• Elderly (≥80 years): Target SBP < 150 mmHg per ACP; < 140 mmHg if tolerated (ESC/ESH recommends treatment at SBP ≥160 mmHg in this age group)
• Older patients with low comorbidity/fall risk: Target SBP < 130 mmHg is appropriate
• Diabetes or heart failure: Higher targets (e.g., < 150 mmHg) if postural hypotension present

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Hypertensive Emergencies and Urgencies

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Special Populations

Older Adults (per Harrison's 22E)

• 70% of older U.S. adults have hypertension
• HYVET trial: treating hypertension in patients ≥80 years to a target ≤150 mmHg significantly reduced stroke, heart failure, and mortality
• SPRINT trial: targeting SBP <120 mmHg reduced composite CVD events and may reduce dementia/MCI risk; excluded patients with diabetes, prior stroke, and heart failure
• Risk of orthostatic hypotension, falls, and syncope must be weighed against CVD benefit
• Use lower initial doses; for dual therapy, prefer ACEI/ARB + diuretic (rather than CCB) if heart failure risk is high

Pregnancy

• Hypertension in ADPKD increases risk of fetal and maternal complications; normotensive women with ADPKD usually have uncomplicated pregnancies
• Gestational hypertension and preeclampsia are distinct entities requiring specific management
• Avoid ACEI and ARBs in pregnancy (teratogenic)
• Preferred agents: labetalol, nifedipine, methyldopa

CKD / Renal Disease

• Hypertension accelerates CKD progression via glomerular hypertension and RAAS activation
• Target BP < 130/80 mmHg with ACEI or ARB as first-line
• In ADPKD: hypertension affects ~50% of young patients with normal renal function and nearly 100% with ESKD

Black Patients

• Higher prevalence, earlier onset, more CVD/renal complications
• Thiazide diuretics and CCBs are especially effective in this population
• Many require triple therapy; RAAS-based therapy should still be included

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Key Clinical Trials

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Resistant Hypertension

• Secondary cause (especially primary aldosteronism, OSA, renal artery stenosis)
• Poor adherence or white coat effect
• Add spironolactone (4th agent), doxazosin, or other agents
• Refer to hypertension specialist

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