What are the different types of pulmonary hypertension and their management options?

Types of Pulmonary Hypertension and Management Options

Pulmonary hypertension (PH) is classified into five distinct groups based on etiology, pathophysiology, and treatment approaches, with each type requiring specific management strategies to reduce morbidity and mortality.

Definition and Diagnosis

• PH is defined as a mean pulmonary arterial pressure ≥25 mmHg at rest as assessed by right heart catheterization 1
• Diagnosis requires right heart catheterization for accurate hemodynamic assessment and proper classification 2

Classification of Pulmonary Hypertension

Group 1: Pulmonary Arterial Hypertension (PAH)

• Characterized by pre-capillary PH with pulmonary vascular resistance >3 Wood units and normal pulmonary artery wedge pressure ≤15 mmHg 1
• Subtypes include:
  • Idiopathic PAH 1
  • Heritable PAH (BMPR2 and other mutations) 1
  • Drug and toxin-induced PAH 1
  • Associated PAH (connective tissue disease, HIV infection, portal hypertension, congenital heart disease, schistosomiasis) 1
• Management involves targeted therapies including:
  • Phosphodiesterase type 5 inhibitors 2
  • Soluble guanylate cyclase stimulators 2
  • Endothelin receptor antagonists 2
  • Prostacyclin analogues and receptor agonists 2, 3

Group 2: PH Due to Left Heart Disease

• Most common form of PH, defined by PAPm ≥25 mmHg with PAWP >15 mmHg 1
• Includes:
  • Left ventricular systolic dysfunction 1
  • Left ventricular diastolic dysfunction 1
  • Valvular disease (present in virtually all patients with severe symptomatic mitral valve disease and up to 65% with symptomatic aortic stenosis) 1
  • Congenital/acquired left heart inflow/outflow tract obstruction 1
• Management primarily focuses on treating the underlying left heart disease rather than using PAH-specific therapies 2, 3

Group 3: PH Due to Lung Diseases and/or Hypoxia

• Includes:
  • Chronic obstructive pulmonary disease 1
  • Interstitial lung disease 1
  • Sleep-disordered breathing 1
  • Alveolar hypoventilation disorders 1
  • Chronic exposure to high altitude 1
• Management focuses on treating the underlying respiratory condition and optimizing oxygenation 3

Group 4: Chronic Thromboembolic PH (CTEPH)

• Characterized by organized thrombi obstructing pulmonary arteries 1
• Includes:
  • Chronic thromboembolic pulmonary hypertension 1
  • Other pulmonary artery obstructions (angiosarcoma, other intravascular tumors, arteritis, congenital pulmonary artery stenoses, parasites) 1
• Management options:
  • Pulmonary endarterectomy is the treatment of choice for eligible patients 2
  • Riociguat (soluble guanylate cyclase stimulator) is the only approved medical therapy for inoperable or persistent/recurrent CTEPH 2, 3
  • Balloon pulmonary angioplasty for selected inoperable patients 3

Group 5: PH with Unclear and/or Multifactorial Mechanisms

• Includes:
  • Hematological disorders (chronic hemolytic anemia, myeloproliferative disorders, splenectomy) 1
  • Systemic disorders (sarcoidosis, pulmonary histiocytosis, lymphangioleiomyomatosis, neurofibromatosis) 1
  • Metabolic disorders (glycogen storage disease, Gaucher disease, thyroid disorders) 1
  • Others (pulmonary tumoral thrombotic microangiopathy, fibrosing mediastinitis, chronic renal failure) 1
• Management focuses on treating the underlying condition 3

Management Considerations

• All patients with suspected PAH or CTEPH should be referred to specialized PH centers 2
• Ventilation-perfusion scanning is essential to exclude CTEPH in all patients with unexplained PH 2
• Right heart catheterization is mandatory for accurate diagnosis and classification 2, 4
• Treatment approach should be based on risk stratification:
  • Low/intermediate risk patients may receive monotherapy or initial oral combination therapy 3
  • High-risk patients should receive combination therapy including intravenous prostacyclin analogues 3
  • Patients with inadequate response to maximum therapy should be assessed for lung transplantation 3

Clinical Pitfalls and Caveats

• Avoid volume overload in patients with right ventricular failure, as this can worsen cardiac output 5
• Vasopressors and inotropes are often preferred over fluid boluses in PH patients with shock 5
• Intubation should be avoided when possible as it can worsen right ventricular function 5
• Abrupt discontinuation of pulmonary vasodilator therapies can lead to rapid clinical deterioration and death 5
• Early consultation with PH specialists and transfer to tertiary care centers may be necessary for advanced interventions like inhaled pulmonary vasodilators, right ventricular assist devices, or extracorporeal membrane oxygenation 5