Key Facts

Hypertension affects ~1 in 3 UK adults and is the leading modifiable risk factor for cardiovascular disease. Optimal BP control reduces risk of stroke by ~40% and MI by ~25%.

Epidemiology

• ~14 million adults in UK with hypertension; ~5 million undiagnosed
• Hypertension: leading risk factor for global mortality
• ~50% of treated patients do not achieve target BP

NICE NG136 Algorithm

• Confirm diagnosis: ABPM (≥135/85 daytime average) or HBPM before starting treatment
• Step 1: <55 and non-Black → ACE-i/ARB; ≥55 or Black African/Caribbean → CCB
• Step 2: ACE-i/ARB + CCB
• Step 3: ACE-i/ARB + CCB + thiazide-like diuretic
• Step 4: add spironolactone 25 mg (if K ≤4.5); if K >4.5 → add alpha-blocker (doxazosin) or beta-blocker (bisoprolol)
• Investigate for secondary hypertension if: <40 years, resistant HTN, hypokalaemia, specific clinical features

Pathophysiology

• BP = cardiac output × systemic vascular resistance
• Antihypertensives reduce BP by: ↓ cardiac output (beta-blockers), ↓ SVR (CCBs, ACE-i, ARBs, alpha-blockers), ↓ blood volume (diuretics)
• RAAS: renin → angiotensin I → ACE → angiotensin II → vasoconstriction + aldosterone → Na/water retention
• ACE-i/ARBs: interrupt RAAS → vasodilation, ↓ aldosterone, natriuresis

Hypertension Diagnosis

• Stage 1: clinic BP ≥140/90 AND ABPM/HBPM ≥135/85
• Stage 2: clinic BP ≥160/100 AND ABPM/HBPM ≥150/95
• Stage 3 (severe): clinic systolic ≥180 OR diastolic ≥120

Drug Side Effects

• ACE inhibitors: dry cough (~10–15%), hyperkalaemia, first-dose hypotension, angioedema (rare), AKI
• ARBs: similar to ACE-i but NO cough; angioedema (rare)
• CCBs (amlodipine): ankle oedema, flushing, headache, gingival hyperplasia
• Thiazide-like diuretics: hypokalaemia, hyponatraemia, hyperuricaemia (gout), impaired glucose tolerance
• Spironolactone: hyperkalaemia, gynaecomastia, breast tenderness, menstrual irregularity

Red Flags

• Hypertensive emergency (BP ≥180/120 + target organ damage): encephalopathy, AKI, aortic dissection → urgent IV treatment
• First-dose hypotension with ACE-i: especially if on diuretic, elderly, dehydrated → start at low dose
• Angioedema with ACE-i → stop immediately, never re-challenge; avoid ARBs cautiously (small cross-reactivity risk)
• Hyperkalaemia on ACE-i/ARB + spironolactone → monitor K+ closely

Diagnosis

• ABPM: gold standard — average daytime readings; confirm diagnosis before treatment
• HBPM: alternative if ABPM not tolerated — average readings over 4–7 days

Before Starting

• U&Es: creatinine, K+ — essential before ACE-i/ARB/diuretic/spironolactone
• Urinalysis: proteinuria (ACR) — guides choice (ACE-i preferred in CKD/proteinuria)
• HbA1c, fasting glucose: metabolic risk assessment
• Lipids: cardiovascular risk assessment (QRISK)
• ECG: LVH, arrhythmias

Monitoring

• U&Es: 1–2 weeks after starting/changing ACE-i/ARB/diuretic/spironolactone; then annually
• BP: at 4–8 weeks after each change; aim for target
• Postural BP: in elderly — lying and standing

Special Tests (Secondary Hypertension)

• Renal artery USS/MRA: renal artery stenosis
• Aldosterone:renin ratio: primary aldosteronism (Conn's syndrome)
• 24-hour urinary catecholamines/metanephrines: phaeochromocytoma
• Overnight dexamethasone suppression test: Cushing's syndrome

Stepwise Approach (NICE NG136)

Step 1:

• <55, non-Black: ACE-i (ramipril 2.5 mg OD → 10 mg OD) or ARB (losartan 50 mg OD → 100 mg OD)
• ≥55 or Black: CCB (amlodipine 5 mg → 10 mg OD)

Step 2:

• A + C (ACE-i/ARB + CCB)

Step 3:

• A + C + D (add indapamide 2.5 mg OD or chlortalidone 12.5–25 mg OD)

Step 4 (Resistant HTN):

• If K+ ≤4.5: add spironolactone 25 mg OD (PATHWAY-2 trial)
• If K+ >4.5: add doxazosin 4–8 mg MR OD or bisoprolol 5–10 mg OD
• If still uncontrolled: specialist referral

Target BP

• <80 years: <140/90 (clinic) or <135/85 (ABPM/HBPM)
• ≥80 years: <150/90 (clinic) or <145/85 (ABPM/HBPM)

Non-Pharmacological

• Lifestyle: reduce salt (<6 g/day), exercise (150 min/week), weight loss, limit alcohol, DASH diet
• Smoking cessation: does not directly lower BP but reduces CV risk

Referral Criteria

• Specialist: resistant hypertension (uncontrolled on 4 drugs), suspected secondary hypertension, accelerated HTN
• Renal: CKD with proteinuria and hypertension
• Endocrine: suspected Conn's, phaeochromocytoma, Cushing's

• Treating hypertension reduces stroke risk by ~40% and MI by ~25%
• Target BP achievement: reduces cardiovascular events significantly (SPRINT trial: intensive <120 systolic benefit)
• Resistant hypertension: spironolactone is most effective add-on (PATHWAY-2)
• Medication adherence: major challenge — ~50% of patients non-adherent at 1 year
• Lifestyle modification alone can reduce BP by 5–10 mmHg

NICE NG136 Stepwise Algorithm

Key Landmark Trials