Pulmonary Vascular Disease: PE Risk and Pulmonary Hypertension Classification
Pulmonary vascular disease covers acute pulmonary embolism and pulmonary hypertension. The exam tests pre-test probability, risk stratification, and the distinction between arterial, venous, and post-capillary disease.
Core rules
- Use a validated pre-test probability tool before D-dimer; D-dimer is most useful to exclude PE in low or intermediate probability. Age-adjusted cut-offs reduce unnecessary imaging.
- High-risk PE means hypotension, shock, or cardiac arrest. Systemic thrombolysis is first-line unless contraindicated; intermediate-high-risk patients are monitored and usually not routinely thrombolysed.
- Pulmonary hypertension is classified into five WHO groups: pulmonary arterial hypertension, left heart disease, lung disease or hypoxia, chronic thromboembolic disease, and multifactorial mechanisms.
- Right heart catheterisation confirms PH and distinguishes pre- from post-capillary physiology; vasoreactivity testing is performed in selected PAH patients.
Worked example
A 55-year-old with sudden dyspnoea, syncope, BP 82/50, and CT pulmonary angiography showing bilateral central emboli has high-risk PE. Start anticoagulation and urgent reperfusion - systemic thrombolysis if no contraindication - with haemodynamic support. Do not wait for D-dimer or send the patient home on a direct oral anticoagulant.
Traps
Using PERC in high-probability patients; missing CTEPH in a PE survivor with persistent dyspnoea; calling all PH “PAH”; and forgetting that left heart disease is the commonest cause of PH.