Pulmonary Vascular Diseases

On this page

Pulmonary Hypertension - Pressure Cooker Lungs

  • Definition: Mean Pulmonary Arterial Pressure (mPAP) > 20 mmHg at rest, confirmed by Right Heart Catheterization (RHC). Pulmonary Vascular Resistance (PVR) > 3 Wood units is also significant. $PVR = (mPAP - PAWP) / CO$.

  • Pathophysiology: Vasoconstriction, vascular remodeling (medial hypertrophy, intimal proliferation, fibrosis), in-situ thrombosis, inflammation.

  • Symptoms: Progressive dyspnea (most common), fatigue, exertional chest pain, lightheadedness, syncope.

  • Signs: Loud P2 (often palpable), RV heave/lift, tricuspid regurgitation murmur, ↑JVP (prominent 'a' or 'v' waves), hepatomegaly, peripheral edema, ascites.

  • WHO Classification (Simplified):

    GroupCategoryKey Examples
    1Pulmonary Arterial Hypertension (PAH)Idiopathic (IPAH), Heritable, CTD-PAH, Drug-induced
    2PH due to Left Heart Disease (LHD)HFrEF, HFpEF, Valvular heart disease
    3PH due to Lung Diseases &/or HypoxiaCOPD, ILD, Sleep-disordered breathing, Alveolar hypoventilation
    4PH due to PA Obstructions (CTEPH)Chronic Thromboembolic Pulmonary Hypertension
    5PH with Unclear/Multifactorial MechanismsHematologic, Systemic, Metabolic disorders, Misc.
    WHO Classification of Pulmonary Hypertension
  • Simplified Diagnostic Algorithm:

  • Key Investigations: ECG (RV hypertrophy/strain, RAE), CXR (enlarged PAs, RVH), Echocardiogram (initial non-invasive screening & PAP estimation), RHC (gold standard for diagnosis, severity & vasoreactivity), V/Q scan (essential to rule out CTEPH), PFTs, HRCT chest.

  • Management Goals:

    • Treat underlying cause (e.g., LHD, lung disease).
    • Supportive therapy: Oxygen (if hypoxic), diuretics (for RV failure), anticoagulation (esp. IPAH, HPAH, CTEPH).
    • Targeted therapies (primarily for PAH Group 1): Prostanoids (e.g., epoprostenol), Endothelin Receptor Antagonists (ERAs, e.g., bosentan, ambrisentan), PDE5 inhibitors (e.g., sildenafil, tadalafil), soluble Guanylate Cyclase (sGC) stimulators (e.g., riociguat).

⭐ Right Heart Catheterization (RHC) is mandatory for the diagnosis of pulmonary hypertension and to guide therapy, especially in PAH (Group 1).

Pulmonary Embolism - Clot on the Block

Thrombus obstructs pulmonary artery. Pathophys: Virchow's Triad (endothelial injury, stasis, hypercoagulability). CTPA: Saddle Pulmonary Embolus

  • Risk Factors: Prior VTE, surgery (ortho), cancer, immobility, OCPs/HRT, pregnancy, thrombophilias (Factor V Leiden).
  • Features: Sudden dyspnea, pleuritic pain, cough, hemoptysis. Signs: tachypnea, tachycardia, DVT signs; hypotension (massive PE).
  • Diagnosis:
    • Wells' Score (PE likely >4):
      CriteriaPts
      DVT signs3
      PE #1 Dx3
      HR >1001.5
      Immob/Surg <4wk1.5
      Prev DVT/PE1.5
      Hemoptysis1
      Malignancy1
    • D-dimer (rules out in low prob.), CTPA (gold standard), V/Q scan (if CTPA C/I).
    • ECG: S1Q3T3 (📌), RBBB, sinus tachy. CXR: Often normal; Westermark sign, Hampton's hump.
  • Management:
    • Supportive: O2, fluids/pressors.
    • Anticoagulation: LMWH/UFH then DOACs/VKA (≥3 months).
    • Thrombolysis (alteplase): For massive PE.
    • Catheter-directed therapy/embolectomy: Severe cases. IVC filter if anticoagulation C/I.

⭐ The S1Q3T3 pattern on ECG, though classic, is neither sensitive nor specific for pulmonary embolism.

Cor Pulmonale & CTEPH - Right Heart's Burden

  • Cor Pulmonale: RV hypertrophy/dilation from lung structure/function diseases or pulmonary vasculature (excludes LHD).
    • Causes: COPD (most common), ILD, cystic fibrosis, severe kyphoscoliosis, chronic PE, primary PH.
    • Pathophysiology: Pulmonary hypertension → ↑RV afterload → RV dysfunction.
    • Clinical Features: Underlying lung disease symptoms + dyspnea, fatigue, exertional syncope, peripheral edema, ascites, JVD, loud P2, RV heave, tricuspid regurgitation.
  • CTEPH (Chronic Thromboembolic Pulmonary Hypertension): PH Group 4; unresolved PE leads to obstruction.
    • Diagnosis: V/Q scan (key screening: mismatched perfusion defects); confirm: RHC, CTPA, pulmonary angiography. V/Q scan showing mismatched perfusion defects in CTEPH
    • Management:
      • Lifelong anticoagulation.
      • Pulmonary Endarterectomy (PEA) - potentially curative if eligible.
      • Balloon Pulmonary Angioplasty (BPA) - for non-operable distal disease.
      • Medical: Riociguat.

    ⭐ Pulmonary endarterectomy (PEA) is the treatment of choice and offers a potential cure for eligible patients with CTEPH.

High‑Yield Points - ⚡ Biggest Takeaways

  • Pulmonary Embolism (PE): CTPA for diagnosis; anticoagulation for treatment. Wells score stratifies risk.
  • Pulmonary Arterial Hypertension (PAH): Mean PAP ≥25 mmHg; right heart catheterization for diagnosis.
  • Cor Pulmonale: RV failure from chronic lung disease, typically COPD.
  • Fat Embolism Syndrome: Triad: respiratory distress, neurological deficits, petechial rash post-trauma.
  • Massive PE: Presents with hypotension; requires thrombolysis or embolectomy.
  • D-dimer: High negative predictive value helps exclude PE in low-risk individuals.

Practice Questions: Pulmonary Vascular Diseases

Test your understanding with these related questions

Drug not used in pulmonary hypertension is:

1 of 5

Flashcards: Pulmonary Vascular Diseases

1/10

Pulmonary hypertension may present with exertional _____ and right-sided heart failure

TAP TO REVEAL ANSWER

Pulmonary hypertension may present with exertional _____ and right-sided heart failure

dyspnea

browseSpaceflip

Enjoying this lesson?

Get full access to all lessons, practice questions, and more.

Start Your Free Trial