Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but severe form of pulmonary hypertension that occurs due to persistent obstruction of the pulmonary arteries by organized blood clots (thrombi), which fail to resolve naturally after acute pulmonary embolism. Over time, these unresolved clots can cause increased pressure in the pulmonary circulation, leading to right heart failure and significant morbidity and mortality if left untreated.
What Causes Chronic Thromboembolic Pulmonary Hypertension (CTEPH)?
CTEPH most commonly develops after an episode of acute pulmonary embolism (PE), but it does not occur in all patients with PE. The precise mechanisms remain under investigation, but several factors increase the risk:
- Previous Venous Thromboembolism: A history of DVT or PE is a major risk factor.
- Hypercoagulable States: Inherited or acquired thrombophilia, such as antiphospholipid syndrome, protein C or S deficiency, or factor V Leiden mutation, may contribute.
- Surgical Interventions or Indwelling Catheters: These can increase clot formation risks.
- Splenectomy: Removal of the spleen has been associated with increased CTEPH risk.
- Chronic Inflammatory Disorders: Conditions such as inflammatory bowel disease or osteomyelitis may predispose individuals to CTEPH.
Importantly, CTEPH may also occur in patients with no known predisposing risk factor.