Idiopathic pulmonary arterial hypertension (Group 1 PAH)
Encounter flow
12/12 authoredCanonical 12-phase frame with authored status for this dossier.
Frame
Confirm Group 1 PAH per 2022 ESC/ERS — mPAP ≥20 + PVR >2 WU + PCWP ≤15 + exclusion of Groups 2–5
Group 1 confirmed; CTEPH and Groups 2/3/5 excluded
Patient inputs (23)
Mandatory to exclude CTEPH (Group 4) before labelling Group 1 (ESC/ERS 2022 Class I)
Exclude Group 3 (lung disease) (ESC/ERS 2022)
Age + sex shapes risk score; women 4:1 in IPAH (ESC/ERS 2022)
Systemic SBP <100 + tachycardia = REVEAL high-risk (Benza CHEST 2012)
HR >=90 = high-risk (REVEAL Lite 2.0)
Resting SpO2 + 6MWT desaturation; supplemental O2 if <90% (ESC/ERS 2022)
eGFR for diuretic + drug clearance (ESC/ERS 2022)
ERA hepatotoxicity baseline + monthly monitoring (bosentan REMS; macitentan less) per ESC/ERS 2022
PAH + pregnancy = ~30% maternal mortality; ERAs teratogenic; mandatory monthly during ERA (ESC/ERS 2022)
Detect existing PAH therapy + nitrates / PDE5 contraindications + ERA-induced LFT changes (ESC/ERS 2022)
GOLD STANDARD diagnosis: mPAP >=20, PVR >2 WU, PCWP <=15; vasoreactivity test in IPAH only (ESC/ERS 2022 Humbert)
NT-proBNP <300 = low-risk; >1100 = high-risk; tracks RV strain (ESC/ERS 2022 4-strata)
Initial screening; RVSP, TAPSE, RV/LV ratio, septal flattening, pericardial effusion (ESC/ERS 2022)
6MWD <165 m = high-risk; >440 m = low-risk per 4-strata score
WHO FC I-IV — primary driver of treatment intensity + risk (ESC/ERS 2022 4-strata)
CTD-PAH workup — ANA, anti-Scl70, anti-centromere, anti-RNP for SSc/MCTD; APS (ESC/ERS 2022)
HIV-PAH is Group 1 subtype (ESC/ERS 2022)
Portal HTN + Hep B/C -> portopulmonary HTN (Group 1) (ESC/ERS 2022)
Drug- and toxin-induced PAH (Group 1.3) (ESC/ERS 2022)
Heritable PAH (BMPR2/ACVRL1/ENG/SMAD9/CAV1/KCNK3) (ESC/ERS 2022)
RVH, RAD, RBBB, RV strain — supportive (ESC/ERS 2022)
RV mass, function, LGE — prognostic adjunct (ESC/ERS 2022)
Serial BNP for monitoring response (ESC/ERS 2022)
* = hard-required. Engine cannot meaningfully run until these are filled.
Severity triggers (7)
- informationallife_threateningwho_fc_iv_or_syncopeWHO FC IV (symptoms at rest) OR exertional syncopeTrigger could not be auto-evaluated — needs clinician judgement.
- informationallife_threateningrv_failure_signsRV failure — JVD elevated, ascites, hepatic congestion, hypotension, oliguria, lactate elevation (ESC/ERS 2022 Humbert)Trigger could not be auto-evaluated — needs clinician judgement.
- informationallife_threateningpregnancy_in_PAHPositive pregnancy test in PAH patient (ESC/ERS 2022 — Class III contraindication)Trigger could not be auto-evaluated — needs clinician judgement.
- informationallife_threateningpump_failure_iv_prostacyclinIV prostacyclin pump failure or line disconnectionTrigger could not be auto-evaluated — needs clinician judgement.
- informationalseverelft_3x_uln_on_eraAST/ALT ≥3× ULN on bosentan / macitentan / ambrisentanTrigger could not be auto-evaluated — needs clinician judgement.
- informationalseverepericardial_effusion_progressionNew or enlarging pericardial effusion on echoTrigger could not be auto-evaluated — needs clinician judgement.
- informationalmoderatesix_min_walk_drop_50m_or_ntprobnp_double6MWD drop >50 m OR NT-proBNP doubling at follow-upTrigger could not be auto-evaluated — needs clinician judgement.
Workflow calculators
Run this disease's risk and dosing calculators inline.
Recommended regimen
PAH-specific therapy by ESC/ERS 4-strata risk score- macitentanfirst lineERA10 mg • PO • once dailytriggers: low_risk_PAHSERAPHIN — reduced morbidity/mortality endpoint; once-daily; less hepatotoxic than bosentanrxcui 1442132
- ambrisentanfirst lineERA5 mg • PO • once daily (max: 10 mg/day)triggers: low_risk_PAHAMBITION dual upfront with tadalafilrxcui 358274
- tadalafilfirst linePDE5_inhibitor20 mg • PO • once daily (max: 40 mg/day)triggers: low_risk_PAHPHIRST + AMBITION; once-daily; no nitrate userxcui 358263
- sildenafilfirst linePDE5_inhibitor20 mg • PO • TID (max: 80 mg TID)triggers: low_risk_PAH, tadalafil_unavailableSUPER-1; less convenient than tadalafil; no nitrate userxcui 136411
outpatient playbook — drug actions (6)
- 1. ERA + PDE5imacitentan 10 mg + tadalafil 40 mg (or ambrisentan 10 mg + tadalafil 40 mg) • PO • once dailytrigger: Low-risk Group 1 PAHAMBITION + SERAPHIN
- 2. add prostacyclin (oral selexipag, inhaled treprostinil, or SC treprostinil)selexipag 200 mcg → 1600 mcg BID; treprostinil inhaled 3 → 12 breaths QID; treprostinil SC 1.25 ng/kg/min → titrate • PO/inhaled/SC • BID/QID/continuoustrigger: Intermediate-risk on dualGRIPHON / TRIUMPH
- 3. sotatercept0.3 → 0.7 mg/kg SC q3 wks • SC • q3 wkstrigger: Intermediate-high or high-risk on background therapySTELLAR / ZENITH
- 4. IV epoprostenol or IV treprostinilepoprostenol 2 ng/kg/min → titrate; treprostinil IV 1.25 ng/kg/min → titrate • IV continuous • continuous via central linetrigger: High-risk / WHO FC IVOnly therapy with mortality benefit in high-risk
- 5. high-dose CCB — vasoreactivity-positive IPAH onlyamlodipine 5 -> 20 mg or diltiazem 120 -> 720 mg/day • PO • daily/TIDtrigger: Acute vasoreactivity test positive (mPAP fall >=10 to <40 + preserved CO)~10% of IPAH; reassess at 3-6 mo (ESC/ERS 2022)
- 6. supportive — diuretic + O2 + iron repletionfurosemide 20–40 mg PO daily; O2 titrated to SpO2 ≥92%; iron sucrose 200 mg IV per protocol • PO/inhaled/IV • daily/continuous/protocoltrigger: RV failure / hypoxemia / iron deficiency2022 ESC/ERS
Auto-drafted A&P note
outpatientSubjective
- Possible entry pathways: Progressive exertional dyspnea unexplained by left HD or lung disease (ESC/ERS 2022); Exertional syncope / presyncope — high-risk PAH presentation (ESC/ERS 2022); Right HF signs — JVD, peripheral edema, ascites, hepatic congestion (ESC/ERS 2022).
Objective
- No vitals, labs, or imaging entered for this encounter.
Assessment
**Idiopathic pulmonary arterial hypertension (Group 1 PAH)** (cardio.idiopathic-pulmonary-arterial-hypertension.v1). Phenotype framing: Confirm Group 1 subtype per ESC/ERS 2022: 1.1 idiopathic, 1.2 heritable, 1.3 drug/toxin, 1.4 CTD/HIV/portopulm/CHD/schistosomiasis, 1.5 PVOD/PCH Scope: Confirm Group 1 PAH per 2022 ESC/ERS — mPAP ≥20 + PVR >2 WU + PCWP ≤15 + exclusion of Groups 2–5 No severity triggers fired against current inputs.
Plan
Regimen axis: **PAH-specific therapy by ESC/ERS 4-strata risk score** — step "Low-risk — ERA + PDE5i dual therapy upfront (AMBITION)". 1. macitentan 10 mg PO once daily (ERA, first line) — SERAPHIN — reduced morbidity/mortality endpoint; once-daily; less hepatotoxic than bosentan 2. ambrisentan 5 mg PO once daily (ERA, first line) — AMBITION dual upfront with tadalafil 3. tadalafil 20 mg PO once daily (PDE5_inhibitor, first line) — PHIRST + AMBITION; once-daily; no nitrate use 4. sildenafil 20 mg PO TID (PDE5_inhibitor, first line) — SUPER-1; less convenient than tadalafil; no nitrate use Setting playbook (outpatient) — Confirm diagnosis at PAH expert centre, exclude CTEPH/Group 2/3/5, risk-stratify, initiate risk-matched therapy, achieve low-risk profile 5. ERA + PDE5i macitentan 10 mg + tadalafil 40 mg (or ambrisentan 10 mg + tadalafil 40 mg) PO once daily — Low-risk Group 1 PAH (AMBITION + SERAPHIN) 6. add prostacyclin (oral selexipag, inhaled treprostinil, or SC treprostinil) selexipag 200 mcg → 1600 mcg BID; treprostinil inhaled 3 → 12 breaths QID; treprostinil SC 1.25 ng/kg/min → titrate PO/inhaled/SC BID/QID/continuous — Intermediate-risk on dual (GRIPHON / TRIUMPH) 7. sotatercept 0.3 → 0.7 mg/kg SC q3 wks SC q3 wks — Intermediate-high or high-risk on background therapy (STELLAR / ZENITH) 8. IV epoprostenol or IV treprostinil epoprostenol 2 ng/kg/min → titrate; treprostinil IV 1.25 ng/kg/min → titrate IV continuous continuous via central line — High-risk / WHO FC IV (Only therapy with mortality benefit in high-risk) 9. high-dose CCB — vasoreactivity-positive IPAH only amlodipine 5 -> 20 mg or diltiazem 120 -> 720 mg/day PO daily/TID — Acute vasoreactivity test positive (mPAP fall >=10 to <40 + preserved CO) (~10% of IPAH; reassess at 3-6 mo (ESC/ERS 2022)) 10. supportive — diuretic + O2 + iron repletion furosemide 20–40 mg PO daily; O2 titrated to SpO2 ≥92%; iron sucrose 200 mg IV per protocol PO/inhaled/IV daily/continuous/protocol — RV failure / hypoxemia / iron deficiency (2022 ESC/ERS) Non-pharmacologic actions: - Refer to PAH expert centre (Class I) (ESC/ERS 2022) - Lung transplant evaluation if intermediate-high/high after triple therapy (ESC/ERS 2022) - PAH-specific exercise rehab (ESC/ERS 2022) - Pneumococcal + annual influenza + COVID + RSV vaccinations (ESC/ERS 2022) - Contraception counselling (pregnancy contraindicated) (ESC/ERS 2022) - Avoid pregnancy, high altitude, decongestants, NSAIDs (preload-dependent RV) (ESC/ERS 2022) - Mental-health support — depression and anxiety prevalent (ESC/ERS 2022) AVOID / contraindication checks: - ERA block in pregnancy mandatory contraception (ESC/ERS 2022) - Bosentan monthly LFT stop if 3xULN (BREATHE 1; ESC/ERS 2022) - PDE5i block if on nitrates (ESC/ERS 2022) - Riociguat NEVER combine with PDE5i (PATENT PLUS; ESC/ERS 2022) - High dose CCB only if vasoreactivity positive (ESC/ERS 2022) - Epoprostenol never stop abruptly (ESC/ERS 2022) - Sotatercept monitor CBC for erythrocytosis (STELLAR NEJM 2023)
Monitoring
Regimen monitoring: - 6MWD q3m (ESC/ERS 2022) - NT-proBNP q3m (ESC/ERS 2022) - WHO FC q3m (ESC/ERS 2022) - echo q6m (ESC/ERS 2022) - RHC at baseline then after escalation or q3-5y (ESC/ERS 2022) - LFT monthly on bosentan (BREATHE-1 REMS) - LFT q3m on macitentan/ambrisentan (SERAPHIN, Pulido NEJM 2013) - pregnancy test monthly on ERA (ESC/ERS 2022) - CBC q3m on sotatercept (STELLAR NEJM 2023) Setting (outpatient) monitoring: - q3 mo follow-up: WHO FC + 6MWD + NT-proBNP + echo (ESC/ERS 2022) - RHC at baseline, after escalation, then q3-5 y or earlier if deteriorating (ESC/ERS 2022) - LFT monthly on bosentan; q3 mo on macitentan/ambrisentan (ESC/ERS 2022; SERAPHIN) - Pregnancy test monthly on ERA (ESC/ERS 2022) - CBC q3 mo on sotatercept (erythrocytosis monitoring) (STELLAR NEJM 2023) Follow-up plan: PAH-specific exercise rehab; pneumococcal/influenza/COVID vaccinations; contraception counselling; mental-health support - Close-out criterion: follow-up scheduled with PAH expert center Monitoring phase: q3 mo follow-up with WHO FC + 6MWD + NT-proBNP + echo; q6 mo RHC if intermediate/high or after escalation; LFT monthly on bosentan; pregnancy test monthly on ERA
Disposition
Current setting: outpatient — Confirm diagnosis at PAH expert centre, exclude CTEPH/Group 2/3/5, risk-stratify, initiate risk-matched therapy, achieve low-risk profile Disposition criteria: - Continue chronic management at PAH expert centre (ESC/ERS 2022) - Lung transplant referral if intermediate-high/high after triple therapy + sotatercept (ESC/ERS 2022) - Palliative care if not transplant candidate (ESC/ERS 2022) Escalation triggers (move to higher acuity): - WHO FC IV / syncope / RV failure -> admit + IV prostacyclin + transplant referral (ESC/ERS 2022) - New pericardial effusion / RV dilation worsening -> escalate therapy (ESC/ERS 2022) - 6MWD drop >50 m or NT-proBNP doubling -> reassess + escalate (ESC/ERS 2022)
Patient Action Plan
**PAH home action plan (RV-failure zones)** Personalised values: baseline_6MWD, baseline_NTproBNP, home_diuretic, O2_baseline_LPM, PAH_centre_phone. **Stable — at baseline 6MWD, no new dyspnea, weight steady** (green): Triggers: - No new shortness of breath at rest or on usual activity (ESC/ERS 2022) - No new ankle / leg swelling, abdominal fullness, or weight gain (ESC/ERS 2022) - Daily home weight within 1 kg of baseline (ESC/ERS 2022) - SpO2 >=92% on baseline O2 (ESC/ERS 2022) Actions: - Take all PAH meds exactly as prescribed (NEVER stop IV/SC prostacyclin abruptly — life-threatening rebound) (ESC/ERS 2022) - Sodium <2 g/day; fluids per plan (ESC/ERS 2022) - Daily weight at the same time, after voiding (ESC/ERS 2022) - Continue prescribed exercise plan (ESC/ERS 2022) - Keep all PAH centre appointments (ESC/ERS 2022) **Caution — new RV strain or congestion** (yellow): Triggers: - Weight gain >2 kg in 3 days (ESC/ERS 2022) - New ankle / leg swelling, abdominal fullness, or RUQ discomfort (ESC/ERS 2022) - New shortness of breath on lower-than-usual activity (ESC/ERS 2022) - New palpitations or dizziness (ESC/ERS 2022) - Pump alarms or site pain (SC) (ESC/ERS 2022) Actions: - Take prescribed rescue diuretic dose (ESC/ERS 2022) - Tighten sodium intake (ESC/ERS 2022) - Check pump function, site, and infusion line if applicable (ESC/ERS 2022) - Call PAH centre within 24 h (ESC/ERS 2022) Contact provider when: - No improvement after 24-48 h of rescue diuretic (ESC/ERS 2022) - Pump malfunction or line concern (any time) (ESC/ERS 2022) - New oxygen requirement above baseline (ESC/ERS 2022) **Medical alert — RV failure or pump failure** (red): Triggers: - Severe shortness of breath at rest, cannot lie flat (ESC/ERS 2022) - Fainting, near-fainting, or chest pain (ESC/ERS 2022) - New confusion or extreme drowsiness (ESC/ERS 2022) - Pump stopped / line disconnected (IV/SC prostacyclin) (ESC/ERS 2022) - Hemoptysis (ESC/ERS 2022) - BP <90 systolic with cool extremities (ESC/ERS 2022) Actions: - Call 911 / emergency services immediately (ESC/ERS 2022) - For IV prostacyclin pump failure establish backup line/pump or send EMS to PAH centre directly (ESC/ERS 2022) - Sit upright (ESC/ERS 2022) - Do NOT lie flat (ESC/ERS 2022) - Bring medication list and PAH centre contact (ESC/ERS 2022) Contact provider when: - Any red zone symptom — ED + page PAH centre on the way (ESC/ERS 2022)
Earlier-Return Triggers
Return-precaution thresholds (watch for): - [LIFE_THREATENING] WHO FC IV (symptoms at rest) OR exertional syncope - [LIFE_THREATENING] RV failure — JVD elevated, ascites, hepatic congestion, hypotension, oliguria, lactate elevation (ESC/ERS 2022 Humbert) - [LIFE_THREATENING] Positive pregnancy test in PAH patient (ESC/ERS 2022 — Class III contraindication)
Citations
- 2022 ESC/ERS Pulmonary Hypertension Guidelines + 2026 ATS/CHEST/PHA PAH Update [PMID:36017548](https://pubmed.ncbi.nlm.nih.gov/36017548/) - Cited evidence (PMID 23984728) [PMID:23984728](https://pubmed.ncbi.nlm.nih.gov/23984728/) - Cited evidence (PMID 26308684) [PMID:26308684](https://pubmed.ncbi.nlm.nih.gov/26308684/) - Cited evidence (PMID 26699168) [PMID:26699168](https://pubmed.ncbi.nlm.nih.gov/26699168/) - Cited evidence (PMID 23883378) [PMID:23883378](https://pubmed.ncbi.nlm.nih.gov/23883378/) Last reconciled with current guidelines: 2026-04-28.
- 2022 ESC/ERS Pulmonary Hypertension Guidelines + 2026 ATS/CHEST/PHA PAH Update — PMID:36017548
- Cited evidence (PMID 23984728) — PMID:23984728
- Cited evidence (PMID 26308684) — PMID:26308684
- Cited evidence (PMID 26699168) — PMID:26699168
- Cited evidence (PMID 23883378) — PMID:23883378