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Pulmonary Hypertension

Pakinam Mekki

Background

  • Symptoms: insidious dyspnea, exertional chest pain, orthopnea, PND, edema

  • Exam: JVD, increased P2, split S2, RV heave, TR murmur, hepatomegaly, ascites, edema

  • Signs of RV failure: low cardiac output (hypotension, renal failure, hepatic congestion), arrhythmias, refractory hypoxemia (R→L shunt), effusions (pericardial > pleural) 

  • WHO Groups and Causes: 

    • Group 1: Pulmonary arterial hypertension (PAH): obliteration of blood vessels in the lung 

      • Idiopathic, heritable 

      • Drugs/toxins (methamphetamine) 

      • Associated with CTD, HIV, portal HTN, congenital heart disease, schistosomiasis 

      • Pulmonary veno-occlusive disease (PVOD), pulmonary capillary hemangiomatosis 

    • Group 2: Left heart disease: back pressure and passive congestion 

      • HFrEF, HFpEF, valvular disease, LA stiffness 

    • Group 3: Chronic lung disease: chronic hypoxemia, chronic pulmonary vasoconstriction 

      • COPD, ILD, OSA, chronic high-altitude, developmental lung disorders 

    • Group 4: Chronic thromboembolic pulmonary hypertension (CTEPH) 

    • Group 5: Multifactorial

      • Hematologic disorders, chronic hemolytic anemia, sarcoidosis, pulmonary Langerhans cell histiocytosis, fibrosing mediastinitis, metabolic disorders 

Evaluation

  • Most common reason for admission with a known diagnosis of pHTN is volume overload/RV failure and hypoxia

    • Consider etiology of decompensation: Progression of underlying disease, medication/dietary nonadherence, infection, arrhythmia, myocardial infarction/RV ischemia, shunting via opening a PFO as a release valve, pulmonary embolism

  • Consult pulmonary hypertension with any questions or assistance with workup

  • Studies to consider ordering to determine etiology of pulmonary hypertension

    • Labs: BNP, liver enzymes, rheumatologic serologies (ANA w/ reflex ENA, RF/CCP, ANCA, Scl-70, Ro/LA)

    • EKG: R-axis deviation, RBBB, increased P wave in lead II

    • CXR: increased PA and R heart border, vascular pruning

    • TTE w bubble: RVSP >35-40, RV dilation and dysfunction, RA dilation, septal flattening, pericardial effusion, evaluate for L heart disease and shunt

    • PFT (outpatient): isolated decrease in DLCO in group I PH, TLC \< 50%, FEV/FVC \< 70%

    • V/Q scan or CTA chest to evaluate for CTEPH

    • 6-minute walk test is prognostic, can be used to monitor response to therapy

    • ± CT chest to evaluate for parenchymal lung disease

    • ± sleep study to evaluate for OSA

    • Right heart catheterization (RHC) is the gold standard test for PH diagnosis and determines pre-vs post-capillary HTN (See RHC section in Cardiology)  

      • Nitric oxide challenge to assess for drug response

      • Fluid challenge with 500cc LR to assess left heart compliance `

Definitions Characteristics Causes
Pre-capillary PH

mPAP > 20 mmHg

PAWP ≤ 15 mmHg

PVR ≥ 3 WU

 Groups 1, 3, 4, 5
Post-capillary PH

mPAP > 20 mmHg

PAWP > 15 mmHg

PVR < 3 WU

 Group 2

Combined pre- and post-

capillary PH

mPAP > 20 mmHg

PAWP > 15 mmHg

PVR ≥ 3 WU

 Group 2, 5

Poor Prognostic Indicators for pHTN

  • NYHA Functional Class (FC III-IV) - 6-minute walk test \< 300

  • AKI - Hyponatremia

  • Low SBP (SBP \< 90) - CTD or liver disease as etiology

  • Poor hemodynamics on RHC (RAP > 20; cardiac index \< 2)

  • TTE findings - TAPSE \< 1.8, pericardial effusion, severe RV dysfunction

Management

  • Goal of hospitalization is to understand and optimize hemodynamics

  • Overall goal- improve NYHA functional class, RV function, 6-minute walk test, quality of life

  • General management: treat underlying cause, diuretics for right heart failure, goal SpO2>90%

  • PAH medicines: Consult pulmonary hypertension if considering starting of changing meds

  • Oral treatments may be used as monotherapy or in combination 

    • Calcium-channel blockers → patients with + vasoreactive challenge 

    • NO-cGMP enhancers: PDE5-inhibitors sildenafil or tadalafil, riociguat 

    • Endothelin receptor antagonists (ERAs): Bosentan, macitenatan, ambrisentan –

  • Prostacyclin analogs

    • Prostacyclin analogs increase cAMP-mediated pulmonary vasodilation. Side effects include jaw pain, flushing, arthralgia, diarrhea.

    • IV formulations are administered through a continuous pump. Never stop IV prostacyclins, even brief pauses can cause rebound vasoconstriction and death. In an emergency, can run temporarily through PIV

      • Epoprostenol: IV (Veletri) or inhaled (Flolan), half-life 4 minutes.

      • Treprostinil: IV/subcutaneous/inhaled/PO, half-life 4 hours 

      • Iloprost: inhaled, half-life minutes 

      • Selexipag (Uptravi): PO, half-life hours 

  • Treatment based on NYHA functional classification: 

    • Class I: no treatment or monotherapy 

    • Class II: monotherapy or combination oral therapy 

    • Class III: combination oral therapy or prostacyclin 

    • Class IV: prostacyclin ± oral therapy 

  • Lung transplant for patients who are candidates and failing maximal medical therapy 

  • VA ECMO can be used as bridge to medical therapy or lung transplant 

  • Atrial septostomy- serves as “pop-off” valve and allows for decompression of failing RV; used as definitive palliative procedure or bridge to transplant 

Last update: 2022-06-26 16:21:44