12-phase flow (10)

1. 1FRAME
   Pulmonary hypertension crisis in scleroderma (PAH-SSc WHO Group 1) = acute RV failure with low cardiac output + systemic hypoperfusion in patient with established or newly-diagnosed PAH-SSc. Pathophysiology: scleroderma vasculopathy → progressive pulmonary arterial remodeling (intimal proliferation, medial hypertrophy, plexiform lesions) → elevated PVR → RV pressure overload → RV-PA uncoupling → low cardiac output → cardiogenic shock. Crisis precipitants: infection, surgery, anesthesia, tachyarrhythmia (especially AFib/AFL), anemia, PE, abrupt PH-targeted therapy hold, systemic vasodilator administration. Pharmacology pivot: PULMONARY-SELECTIVE VASODILATORS — iNO 20-40 ppm + IV milrinone (negative-afterload inotrope reducing PVR + improving RV-PA coupling) + cautious diuresis (RV preload-dependent); INTRAVENOUS PROSTACYCLIN (epoprostenol IV 2 ng/kg/min titrate); PDE5i (sildenafil PO bridge); AVOID systemic vasodilators (NTG, hydralazine — worsen V/Q mismatch). RV-MCS (RVAD/VA-ECMO) bridge to lung transplant for refractory. Route to parent engine for shared HTN-emergency arc; this dossier owns the PAH-specific pharmacology + RV failure assessment + transplant pathway.
   inputs: sbp, heart_rate, oxygen_saturation, systemic_sclerosis_subtype_and_duration
   advance: PAH-SSc + acute RV failure phenotype identified + ICU triage initiated
2. 2ENTRY
   Recognize PAH-SSc crisis (known or newly suspected PAH + acute RV failure with hypoxia + low SBP + JVD + edema + oliguria); supplemental O2 to SpO2 ≥92% (hypoxia worsens PVR); cardiac monitor + a-line; vascular access for prostacyclin (dedicated central line); contact PH center if not already established
   inputs: age, oxygen_saturation, sbp
   advance: IV access + a-line + cardiac monitor + O2 + PH-team contacted
3. 3CONTEXT
   SSc duration + subtype (limited cutaneous + CREST → highest PAH risk; long duration); current PH-targeted therapy (which agents, last dose, recent changes); precipitants (infection, recent surgery, anesthesia, tachyarrhythmia, recent therapy hold, recent travel, pregnancy); concurrent SSc-ILD (changes WHO Group classification + therapy approach); transplant listing status
   inputs: age, systemic_sclerosis_subtype_and_duration
   advance: context complete with PH-targeted therapy + transplant status documented
4. 4RED_FLAGS
   Cardiogenic shock from RV failure (SBP <90 + lactate elevated + cool extremities + oliguria); concurrent scleroderma renal crisis (DDX from THIS PAH-crisis dossier — both are scleroderma vasculopathy emergencies but different pathophysiology); pulmonary embolism (RV crisis precipitant — CTPA if hemodynamically stable); concurrent SSc cardiac involvement (myocardial fibrosis, pericardial effusion → tamponade); tachyarrhythmia (AFib/AFL → rate control challenging given RV strain); critical AVOID — systemic vasodilators (NTG, hydralazine), high-dose IV fluids (RV overload), positive-pressure ventilation (worsens RV preload), beta-blocker (negative inotropy in already-failing RV)
   inputs: sbp, lactate, oxygen_saturation
   actions: htn_emergency
   advance: shock + PE + concurrent SRC + tamponade + arrhythmia screened
5. 5INITIAL_WORKUP
   BNP / NT-proBNP (RV strain + prognosis); troponin (RV ischemia); BMP + Mg + Ca (lactate, Cr, K); CBC (anemia worsens PAH); LFT (hepatic congestion); ABG (hypoxia + acid-base); ECG (RV strain, arrhythmia); echo (PASP, RV size/function, TAPSE, septal flattening, IVC, pericardial effusion); CXR; troponin trend; coag if anti-Xa or anticoagulation
   inputs: bnp_or_ntprobnp, troponin, creatinine, lactate, echo_with_PASP_and_RV_assessment, ecg
   actions: panel.cardiac, panel.renal, panel.coag, panel.abg
   advance: workup documented + RV failure severity stratified
6. 6BRANCHING_WORKUP
   Right heart cath (definitive diagnosis + hemodynamic assessment — mPAP, PVR, PAWP, CO, mixed venous O2 sat) — RHC may be deferred in unstable patient and treated empirically; HRCT chest (rule out WHO Group 3 from SSc-ILD); CTPA if PE suspected (cautious — contrast in cardiorenal); cardiac MRI (RV function + fibrosis); 6MWT once stable (functional class); RNA-pol III + anticentromere antibodies if not yet sent (CENP-B = highest PAH risk in limited cutaneous SSc)
   inputs: right_heart_cath, hrct_chest
   advance: WHO Group 1 vs 3 classification + transplant evaluation initiated
7. 7TREATMENT
   STEP 1 — supportive: O2 to SpO2 ≥92% (hypoxia worsens PVR); avoid systemic vasodilators; cautious diuresis (preload-dependent RV — start low-dose furosemide 20-40 mg IV with continuous CVP/IVC monitoring); avoid positive-pressure ventilation if possible (worsens RV preload); rate control AFib/AFL (digoxin acceptable, avoid BB/CCB which depress RV; cardioversion if hemodynamic instability). STEP 2 — pulmonary-selective vasodilator escalation: INHALED NITRIC OXIDE (iNO) 20-40 ppm via mask or vent (rapid pulmonary vasodilation without systemic drop); IV MILRINONE 0.25-0.5 mcg/kg/min (negative-afterload inotrope; reduces PVR + improves RV-PA coupling; watch SVR drop); INTRAVENOUS EPOPROSTENOL (start 2 ng/kg/min, titrate by 1-2 ng/kg/min q15-60 min — rapid PVR reduction; dedicated central line + 24/7 infusion mandatory; abrupt cessation = fatal rebound). STEP 3 — bridge oral therapy: SILDENAFIL 20 mg PO TID (PDE5i — pulmonary-selective vasodilator); RIOCIGUAT (sGC stimulator) per PATENT-1 PMID 23883378 if PDE5i ineffective. STEP 4 — combination chronic therapy per AMBITION/SERAPHIN/GRIPHON: ERA (ambrisentan/macitentan) + PDE5i (sildenafil/tadalafil) + prostacyclin pathway (epoprostenol IV / treprostinil SC/inhaled / selexipag PO). STEP 5 — refractory: RV-MCS (RVAD or VA-ECMO) bridge to LUNG TRANSPLANT (PAH-SSc transplant evaluation early — long waitlist; bilateral lung > heart-lung). AVOID: systemic vasodilators (NTG, hydralazine — worsen V/Q + drop SVR), CCB unless +vasoreactivity (PAH-SSc rarely vasoreactive), beta-blocker (negative inotropy in failing RV), high-dose IV fluids (RV preload overload), positive-pressure ventilation if possible.
   inputs: sbp, heart_rate, oxygen_saturation, creatinine, lactate
   advance: PVR reduction + cardiac output improvement + transplant evaluation initiated if refractory
8. 8DISPOSITION
   ICU mandatory with PH-experienced team + a-line + dedicated central line for prostacyclin; PH center transfer if not already; lung transplant team consult; rheumatology consult; nephrology if AKI; palliative care for refractory advanced disease
   advance: ICU bed + PH-experienced team + transplant + rheumatology consults booked
9. 9MONITORING
   A-line + central line for hemodynamics; continuous SpO2 + ECG; q1-4h vitals + UOP; q4-6h BMP + lactate; daily BNP/NT-proBNP + troponin + echo (TAPSE trajectory); RHC q24-48h if catheter-stable for hemodynamic optimization; serial 6MWT once stable; weekly transplant listing review
   inputs: sbp, oxygen_saturation, lactate
   actions: panel.cardiac, panel.renal
   advance: hemodynamics optimizing + RV recovering + transplant timeline + chronic regimen converted
10. 10FOLLOWUP
    Lifelong PH center + rheumatology + cardiology + transplant team coordination; combination triple therapy (ERA + PDE5i + prostacyclin) per AMBITION/SERAPHIN/GRIPHON; quarterly REVEAL 2.0 risk reassessment; pulmonary HTN registry; bilateral lung transplant listing for severe (FC III-IV despite max therapy); avoid pregnancy (high mortality in PAH); avoid systemic vasodilators; AVOID erectile dysfunction PDE5i if on PAH PDE5i (additive hypotension)
    advance: lifelong PH center + transplant pathway + chronic PH-targeted therapy stable