Decision support only — not a substitute for the ESC/ERS 2022 guideline, a specialist PH centre, or eTG. PH = mean PAP >20 mmHg on right heart catheterisation. The whole game is getting the group right, because PAH-targeted drugs help Group 1 (and inoperable Group 4) but can harm Groups 2 and 3. PAH therapy should be initiated at an expert centre. Verify all doses.
1 The five groups — get this right first
Group 1 · PAHpre-capillary
Idiopathic, heritable (BMPR2), drug/toxin (methamphetamine, dasatinib), CTD (scleroderma), congenital heart disease, portopulmonary, HIV.
Targeted PAH therapy (this sheet). Haemodynamics: PAWP ≤15 + PVR >2 WU.
Group 2 · Left heartmost common overall
HFrEF, HFpEF, valvular disease. Post-capillary (PAWP >15).
Treat the left heart. PAH drugs can cause pulmonary oedema — don't use them.
Group 3 · Lung / hypoxia
COPD, interstitial lung disease, OSA, hypoventilation, altitude.
Treat the lung disease + oxygen. PAH drugs generally not used (worsen V/Q) — exception: inhaled treprostinil for ILD-PH INCREASE.
Group 4 · CTEPHpotentially curable
Chronic thromboembolic PH — organised clot, often post-PE.
Pulmonary endarterectomy can cure it. Balloon pulmonary angioplasty ± riociguat if inoperable; lifelong anticoagulation. V/Q scan to find it.
Group 5 · Multifactorialunclear mechanism
Sarcoidosis, chronic haemolytic anaemia, myeloproliferative, metabolic.
Treat the underlying disease; manage at a PH centre.
A V/Q scan is mandatory in the work-up — it is more sensitive than CTPA for CTEPH, and CTEPH is the one surgically curable group, so it must not be missed. Older patients often have mixed Group 2/3 disease — classify by the predominant driver.
2 Define it & confirm it
Haemodynamics (right heart cath)
- PHmPAP >20 mmHg (lowered from ≥25 in 2022).
- Pre-capPAH / Groups 3–5: PAWP ≤15 + PVR >2 WU (PVR threshold lowered from 3).
- Post-capGroup 2: PAWP >15. Combined pre/post if PVR >2 as well (CpcPH).
- RHCGold standard — confirms diagnosis & group, and is mandatory before PAH therapy.
The pathway to it
- EchoScreening tool — PH probability (TR jet/RVSP, RV size/function, TAPSE/sPAP). Not diagnostic alone.
- Work-upPFTs + DLCO, HRCT, V/Q scan, CTD serology, HIV, LFTs (portal HTN), sleep study, NT-proBNP, ECG.
- VasoreactivityAt RHC in idiopathic/heritable/drug-induced (inhaled NO) — identifies the few CCB responders.
- ReferScreen scleroderma & heritable risk; send to an expert PH centre.
3 Treat PAH (Group 1)
Risk-stratified algorithm
- VasoreactivePositive test (a minority) → high-dose CCB; reassess at 3–6 months (response = FC I–II, mPAP <30, PVR <3).
- StratifyOtherwise risk-stratify (WHO FC, 6MWD, NT-proBNP, RHC/imaging — 3 strata at diagnosis).
- Low/intInitial dual oral: ERA + PDE5i AMBITION.
- HighAdd IV/SC prostacyclin (triple therapy) up front.
- Follow-upReassess (4 strata); if not low-risk → escalate (add selexipag GRIPHON or switch to riociguat).
The pathways & what's new
- ERAAmbrisentan, macitentan SERAPHIN, bosentan.
- NO–cGMPPDE5i (sildenafil, tadalafil) or sGC stimulator riociguat — never together.
- ProstacyclinEpoprostenol IV (sickest), treprostinil, iloprost, oral selexipag.
- NewSotatercept (activin-signalling inhibitor) added to background therapy STELLAR.
- SupportDiuretics for RV failure, O₂ if hypoxic, rehab, vaccinate; transplant referral if refractory.
4 The traps
Don't harm
- Wrong groupPAH drugs harm Group 2 (pulmonary oedema) & Group 3 (worse V/Q) — classify before treating.
- Miss CTEPHSkipping the V/Q scan misses the one curable group.
- CCBHigh-dose CCB only if proven vasoreactive — otherwise risk of haemodynamic collapse.
- RiociguatContraindicated with PDE5i or nitrates (hypotension).
Don't miss
- Echo onlyDon't start PAH therapy on echo alone — RHC is mandatory.
- PregnancyContraindicated in PAH (high maternal mortality) — counsel contraception. Stop ERA/riociguat/selexipag (teratogenic); CCB/PDE5i/prostacyclins are the safer options if pregnant.
- PVOD/PCHLow DLCO + ground-glass/septal lines — vasodilators can precipitate fatal pulmonary oedema.
Sources.
Humbert et al. "2022 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension," Eur Heart J / Eur Respir J 2022 (mPAP >20 definition, PVR >2 WU, 5-group classification, echo→V/Q→RHC pathway, vasoreactivity, risk-stratified treatment algorithm, CTEPH multimodal therapy, pregnancy). PH Society of Australia & NZ; eTG; PBS for PAH-drug authority criteria.
Key trials: AMBITION (initial ambrisentan + tadalafil); SERAPHIN (macitentan); GRIPHON (selexipag); STELLAR (sotatercept); INCREASE (inhaled treprostinil in Group 3 ILD-PH); PATENT (riociguat); CHEST (riociguat in inoperable CTEPH).
Caveats: PAH-targeted drugs are PBS authority-restricted and initiated through designated PH centres in Australia — confirm criteria. The lowered mPAP/PVR thresholds widen who meets "PH" — clinical context and group still drive management. Vasoreactivity testing applies to idiopathic/heritable/drug-induced PAH, not CTD- or CHD-associated. Verify all doses. Companion to the cardiac & respiratory sets.