# Chronic Thromboembolic Pulmonary Hypertension

> Chronic thromboembolic pulmonary hypertension for NEET-PG Medicine: V/Q screening, catheter confirmation, endarterectomy, balloon angioplasty and riociguat.

- Canonical URL: https://prepelephant.com/topics/neet-pg/medicine/chronic-thromboembolic-pulmonary-hypertension
- Exam / course: NEET-PG · Subject: Medicine
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-14
- Last updated: 2026-10-14
- Reference basis: Harrison's Principles of Internal Medicine; ESC/ERS guidelines for the diagnosis and treatment of pulmonary hypertension; Davidson's Principles and Practice of Medicine
- How to cite: "Chronic Thromboembolic Pulmonary Hypertension", PrepElephant, https://prepelephant.com/topics/neet-pg/medicine/chronic-thromboembolic-pulmonary-hypertension

## Direct answer

Chronic thromboembolic pulmonary hypertension is a group 4 pulmonary hypertension caused by organised, unresolved thrombus in the pulmonary arteries after one or more pulmonary emboli. It is diagnosed when pulmonary hypertension persists after at least three months of effective anticoagulation, and right heart catheterisation confirms it. Pulmonary endarterectomy is the treatment of choice for operable proximal disease, while balloon angioplasty and riociguat serve patients who cannot have surgery.

## What you must remember

- **Diagnostic trigger:** persistent pulmonary hypertension after at least three months of effective anticoagulation, with unresolved perfusion defects on imaging.
- **Screening test:** the V/Q scan has high sensitivity, and a normal scan effectively excludes chronic thromboembolic disease.
- **Confirmation:** right heart catheterisation shows mean pulmonary artery pressure above 20 mmHg with pulmonary vascular resistance above 2 Wood units.
- **Operability:** pulmonary endarterectomy is first line for operable proximal disease in a fit patient, performed at an experienced centre.
- **Inoperable distal disease:** balloon pulmonary angioplasty treats distal vessels that surgery cannot reach.
- **Drug therapy:** riociguat, a soluble guanylate cyclase stimulator, is used for inoperable disease and for persistent pulmonary hypertension after surgery.
- **Anticoagulation:** lifelong anticoagulation is recommended after diagnosis, usually with warfarin.

## A stepwise pathway from suspicion to treatment

Chronic thromboembolic disease is missed when clinicians stop at an echo estimate of pulmonary pressure. The pathway moves from screening to invasive confirmation before any treatment is chosen.

1. **Suspect the diagnosis:** Consider it in a patient with unexplained breathlessness and exertional limitation after pulmonary embolism, especially when symptoms persist beyond three months.
2. **Screen with V/Q scan:** Multiple segmental mismatched perfusion defects are typical, and a normal scan argues strongly against the diagnosis.
3. **Confirm the anatomy:** CT pulmonary angiography or pulmonary angiography shows organised thrombus, web-like stenosis and eccentric, wall-adherent clot.
4. **Measure haemodynamics:** Right heart catheterisation confirms the diagnosis and measures pulmonary vascular resistance, which guides operability.
5. **Refer to a specialist centre:** A multidisciplinary team decides management, because surgical and balloon options need experienced operators.
6. **Choose treatment:** Operable proximal disease goes to endarterectomy, distal disease to balloon angioplasty, and residual or inoperable disease to riociguat, with lifelong anticoagulation in every case.

## Where the diagnosis slips

Most errors come from relying on a single test or stopping treatment too early.

- **Trap:** diagnosing chronic thromboembolic disease from an echo pressure estimate alone — **Correct:** echo only estimates pulmonary pressure, so right heart catheterisation is needed for confirmation and haemodynamic staging.
- **Trap:** treating a normal V/Q scan as a reason to stop the work-up — **Correct:** a normal scan argues against chronic thromboembolic disease, but other causes of pulmonary hypertension still need evaluation.
- **Trap:** stopping anticoagulation once surgery is complete — **Correct:** lifelong anticoagulation remains part of management even after a successful endarterectomy.

## Frequently asked questions

### Which investigation screens for chronic thromboembolic pulmonary hypertension?
The V/Q scan is the screening test of choice for chronic thromboembolic pulmonary hypertension, because it detects mismatched perfusion defects with high sensitivity. A normal V/Q scan makes chronic thromboembolic disease very unlikely, which is why it is used before invasive tests.

### How long must anticoagulation be given before chronic thromboembolic disease is diagnosed?
Chronic thromboembolic pulmonary hypertension is diagnosed only after at least three months of effective anticoagulation, when pulmonary hypertension persists despite treatment. Many acute emboli resolve within this period, so waiting avoids confusing acute embolic disease with the chronic form.

### When is pulmonary endarterectomy offered?
Pulmonary endarterectomy is offered for operable chronic thromboembolic pulmonary hypertension with proximal thrombus in a surgically fit patient. It is performed at an experienced centre, because outcomes depend heavily on the volume and skill of the surgical team.

### Which drug is used for inoperable chronic thromboembolic pulmonary hypertension?
Riociguat, a soluble guanylate cyclase stimulator, is used for inoperable chronic thromboembolic pulmonary hypertension and for persistent pulmonary hypertension after endarterectomy. Balloon pulmonary angioplasty is an alternative for distal disease that surgery cannot reach.