Pulmonary Hypertension

Ashley Ritossa

WHO Group

Pathophysiology

Etiologies
Group 1.
Pulmonary arterial hypertension 		Proliferation and hyperplasia of vascular wall -> increased pulmonary vascular resistance Idiopathic, heritable, drug-induced/toxin-induced, connective tissue disease (scleroderma), HIV, portal HTN, congenital heart disease, schistosomiasis (#1 cause of PAH worldwide)
Group 2. Left heart disease Elevated end diastolic filling pressure -> Increased PCWP HFrEF, HFpEF, aortic/mitral valve disease, stiff LA
Group 3. Lung diseases or chronic hypoxemia Hypoxic pulmonary vasoconstriction leads to vascular bed remodeling COPD, ILD, OSA, chronic high-altitude exposure
Group 4. Chronic thromboembolic pulmonary hypertension (CTEPH) Chronic pulmonary embolism.
Incomplete fibrinolysis and organization of thrombus 		Thrombotic and non-thrombotic emboli (parasites, foreign bodies, tumor)
Group 5. Multifactorial Varied Hematologic disorders (sickle cell), systemic disorders (sarcoidosis), metabolic disorders, ESRD, fibrosing mediastinitis

Presentation 

  • Main CC for admission: volume overload 2/2 RV failure and/or hypoxia 
  • Symptoms: Exertional dyspnea, presyncope, fatigue, exertional chest pain, edema, syncope (concern for severe PH)
  • Physical Exam Findings: JVD, RV heave, widely split S2, tricuspid regurgitation murmur, hepatomegaly, ascites, rales (pulmonary edema), LE edema

Evaluation/Diagnosis 

  • Labs: 
    • CBC w/ diff, BNP, CMP 
    • TSH, HIV, rheumatologic serologies 
  • Imaging: 
    • CXR: Possible cardiac enlargement, PA dilation, hilar fullness 
    • TTE with bubble: RVSP >35-40 is concerning for PH. May show evidence of RV dilation/dysfunction 
    • CT angiogram or V/Q scan: evaluate for acute and chronic thrombi 
    • High-res CT: evaluation of lung parenchyma 
  • EKG, 6-min walk test, PFTs, sleep study 
  • Right Heart Catheterization: 
    • Gold standard; required for diagnosis and to determine therapeutic options 
    • mPAP > 20 is diagnostic (see chart below)

Definitions

Characteristics

Causes
Pre-capillary PH mPAP > 20 mmHg
PWP ≤ 15 mmHg
PVR ≥ 2 WU		 Groups 1, 3, 4, 5
Post-capillary PH mPAP > 20 mmHg
PWP > 15 mmHg
PVR < 2 WU		 Group 2
Combined pre- and postcapillary PH mPAP > 20 mmHg
PWP > 15 mmHg
PVR ≥ 2 WU		 Group 2, 5

General Management 

  • Treatment Goals: Preventing right heart failure, maximizing PH therapies, symptom relief, quality of life 
  • Oxygenation Goal: Oxygen saturation >90% 
  • Volume/Hemodynamic Management: try to avoid giving fluids, especially if significant RV dysfunction as this is more likely to throw off Frank-Starling curve than over-diuresis 
  • Classic teaching of pre-load dependence is more accurate for acute RV dysfunction than chronic; diuresis often warranted in episodes of RHF 
  • Specialist Consultation: Consult PH specialists when considering starting, holding, or changing PH medications; DO NOT change PH therapy at VUMC without PH consult 
  • *Referral to PH Center is particularly recommended for suspected PAH (Group 1), CTEPH (Group 4), or severe PH with RV dysfunction 
  • Ensure close follow-up with outpatient PH specialist upon discharge 
  • Immunizations strongly recommended

Therapy

Patient Population / Considerations
Oral CCBs
(Nifedipine, diltiazem, amlodipine) 		Used ONLY in pts w/ Group 1 PH who had a positive vasoreactivity challenge on RHC
Anticoagulation (DOAC, VKA) CTEPH (Group 4)
- Also work-up for hypercoagulability
PAH-specific medications (in order of escalation)
Endothelin receptor antagonists
(e.g., bosentan, ambrisentan, macitentan) 		- All therapies given under the direction of PH specialist

Important Notes on Prostacyclin Based Therapies:
- Side effects include jaw pain, flushing, arthralgias, and diarrhea
- IV formulations administered through continuous pump. Never stop IV prostacyclin therapy inpatient since even brief pauses can cause rebound vasoconstriction and death.
Phosphodiesterase-5 inhibitors (e.g., sildenafil, tadalafil)
Prostacyclin analogs (e.g., epoprostenol, treprostinil)
Prostacyclin receptor agonists (e.g., selexipag)
Soluble guanylate cyclase stimulators (e.g., riociguat)
Sotatercept Used as add on therapy in Group 1 PH to enhance exercise capacity, improve functional class, and reduce clinical worsening

Procedural Considerations 

  • Atrial septostomy: creation of a R->L shunt to offload the RV 
  • VA ECMO: bridge to medical therapy or for lung transplant 
  • Lung transplantation: consider in patients failing maximal medical therapy
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