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This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
The Bottom Line
- PH = mPAP >20 mmHg. Classified into 5 WHO groups: Group 1 (PAH — idiopathic, connective tissue disease, drugs); Group 2 (left heart disease — most common overall); Group 3 (lung disease/hypoxia); Group 4 (CTEPH); Group 5 (miscellaneous)
- Presents with progressive exertional dyspnoea, fatigue, syncope, and signs of right heart failure
- Screening: TTE showing elevated RVSP + signs of RV dysfunction. Diagnosis confirmed by right heart catheterisation
- Group 1 PAH: targeted therapies — PDE5 inhibitors (sildenafil), endothelin receptor antagonists (bosentan), prostanoids (epoprostenol)
- Group 2/3: treat underlying cause. Group 4 (CTEPH): consider pulmonary endarterectomy
Overview
Pulmonary hypertension (PH) is defined as a mean pulmonary arterial pressure (mPAP) >20 mmHg measured by right heart catheterisation. The 2022 ESC/ERS classification divides PH into 5 groups. Group 1 (pulmonary arterial hypertension, PAH) involves primary remodelling of the pulmonary arterioles and is the group amenable to targeted vasodilator therapies. Group 2 (left heart disease) is the most common cause of PH overall. Group 3 (lung disease/hypoxia) includes COPD and ILD. Group 4 (chronic thromboembolic PH, CTEPH) is potentially curable with surgery. Group 5 includes multifactorial/unclear mechanisms. PH leads to progressive right ventricular failure and death if untreated.
Epidemiology
PAH (Group 1) has a prevalence of approximately 15–60 per million. It is more common in women (2–4:1). Mean age at diagnosis is approximately 50 years. Idiopathic PAH is the most common subtype. Connective tissue disease (especially systemic sclerosis) is the second most common cause of Group 1 PAH. Group 2 PH (left heart disease) is far more prevalent overall but is usually mild-moderate and managed by treating the underlying heart failure. CTEPH (Group 4) develops in approximately 3–4% of patients after acute PE.
Clinical Features
Symptoms
Progressive exertional dyspnoea (earliest and most common symptom)
Fatigue and lethargy
Exertional syncope or presyncope (fixed cardiac output)
Chest pain (RV ischaemia)
Peripheral oedema, abdominal distension (right heart failure)
Haemoptysis (rare, from bronchial artery hypertrophy)
Signs
Loud P2 (pulmonary component of S2 — palpable in severe PH)
Right ventricular heave (parasternal lift)
Raised JVP with prominent A wave (RV hypertrophy) or V wave (TR)
Pansystolic murmur at lower left sternal edge (tricuspid regurgitation)
Peripheral oedema, hepatomegaly, ascites (right heart failure)
Central cyanosis (right-to-left shunting via PFO or severe V/Q mismatch)
Investigations
First-line
EchocardiographyScreening tool: estimate RVSP (if TR present), assess RV size/function, LV disease. RVSP >35 mmHg + RV dilatation warrants further investigation
ECGRVH (tall R in V1, right axis deviation), P pulmonale (peaked P in II), RBBB
Chest X-rayEnlarged pulmonary arteries, pruning of peripheral vessels, RV enlargement
BloodsBNP/NT-proBNP (prognostic), FBC, TFTs, LFTs, connective tissue disease screen (ANA, Scl-70, anti-centromere), HIV serology
Second-line
CT pulmonary angiographyExclude CTEPH (Group 4). Assess lung parenchyma (Group 3)
Lung function testsAssess for COPD/ILD (Group 3). Reduced DLCO common in PAH
V/Q scanMore sensitive than CTPA for CTEPH — mismatched perfusion defects
Specialist
Right heart catheterisation (gold standard)Confirms diagnosis: mPAP >20 mmHg. Pre-capillary PH: PCWP ≤15 + PVR >2 WU. Post-capillary PH: PCWP >15. Vasoreactivity testing (for idiopathic PAH — if positive → trial of CCBs)
1
General measures (all groups)
- Refer to specialist PH centre
- Supervised exercise rehabilitation
- Diuretics for fluid overload
- Supplemental oxygen if hypoxic (SpO₂ <90%)
- Contraception counselling for women of childbearing age (pregnancy = very high mortality in PAH)
- Influenza and pneumococcal vaccination
- Anticoagulation for CTEPH; consider in idiopathic PAH
2
Group 1 PAH — targeted therapies
- PDE5 inhibitors: sildenafil 20 mg TDS or tadalafil (vasodilator, increases NO)
- Endothelin receptor antagonists (ERA): bosentan, ambrisentan, macitentan (reduce vasoconstriction and proliferation)
- Prostanoids: epoprostenol (IV), iloprost (inhaled), selexipag (oral IP receptor agonist)
- Combination therapy now standard — upfront dual or triple therapy based on risk stratification
- Calcium channel blockers (nifedipine, diltiazem) ONLY for vasoreactive patients on RHC testing (~5%)
3
Group 2 — left heart disease
- Treat underlying heart failure — do NOT use PAH-specific therapies
4
Group 3 — lung disease
- Treat underlying lung disease, optimise oxygenation
- Inhaled treprostinil may be considered for PH-ILD
5
Group 4 — CTEPH
- Pulmonary endarterectomy (PEA) — potentially curative, gold standard
- Balloon pulmonary angioplasty (BPA) if surgery unsuitable
- Riociguat (sGC stimulator) for inoperable CTEPH
6
Advanced/end-stage
- Bilateral lung or heart-lung transplantation
- Atrial septostomy (palliative — right-to-left shunt decompresses RV)
Complications
- Right heart failure: Progressive RV dilatation and failure — the most common cause of death in PAH
- Arrhythmias: AF, atrial flutter (poorly tolerated)
- Haemoptysis: Bronchial artery rupture in severe PH
- Pregnancy: Maternal mortality 30–50% in severe PAH — pregnancy contraindicated
- Renal and hepatic dysfunction: From chronic venous congestion
UKMLA Exam Tips
- 1Loud P2 + RV heave + raised JVP + exertional dyspnoea in a young woman = think PAH
- 2Group 2 (left heart disease) is the MOST COMMON cause of PH overall — but Group 1 (PAH) is what the exam usually tests
- 3V/Q scan is superior to CTPA for diagnosing CTEPH — always request if PH workup shows perfusion defects
- 4Pregnancy is contraindicated in severe PAH — maternal mortality 30–50%
- 5Only ~5% of idiopathic PAH patients respond to CCBs — determined by vasoreactivity testing at RHC
- 6CTEPH is potentially CURABLE with pulmonary endarterectomy — screen all PE survivors who remain symptomatic
practicetest your knowledge on pulmonary hypertensionApply what you've learnt with UKMLA-style questions from the iatroX Q-Bank — cardiovascular and beyond.
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