Chronic Thromboembolic Pulmonary Hypertension (CTEPH): Symptoms, Diagnosis and Treatment

What is CTEPH?

Chronic thromboembolic pulmonary hypertension (CTEPH) develops when blood clots in the lungs (a pulmonary embolism) do not dissolve fully. Instead, they become organised into scar-like material that narrows or blocks the pulmonary arteries. The right side of the heart then has to pump against a high resistance, causing pulmonary hypertension and eventually right heart failure.

CTEPH is rare and develops in only a small minority of people after an acute pulmonary embolism. Some patients have never been told they had a clot. It is classified as Group 4 pulmonary hypertension and is important to recognise because, unlike most forms of pulmonary arterial hypertension, it can often be treated surgically or with catheter procedures.

Assessment and treatment are coordinated with cardiology, interventional radiology and cardiothoracic surgery, with referral to an experienced CTEPH centre for decisions about surgery.

Symptoms of CTEPH

Symptoms are similar to other forms of pulmonary hypertension and often develop gradually:

• Breathlessness on exertion that persists or worsens months after a pulmonary embolism, instead of recovering.
• Fatigue and reduced exercise capacity.
• Chest pain or pressure on effort.
• Dizziness or fainting during activity.
• Swelling of the ankles and abdomen from right heart strain.
• Coughing up blood occasionally.

Anyone who remains breathless three months after a pulmonary embolism, despite adequate anticoagulation, should be assessed for CTEPH.

Causes and risk factors

CTEPH follows one or more episodes of blood clots travelling to the lungs, whether or not they were recognised at the time. Factors that increase the risk include:

• A large or recurrent pulmonary embolism
• Antiphospholipid syndrome and some other clotting disorders
• Previous splenectomy
• Infected pacemaker leads or ventriculo-atrial shunts
• Thyroid replacement therapy, cancer and inflammatory bowel disease
• Blood groups other than O

Why some clots fail to dissolve is not fully understood. Ongoing narrowing of the small vessels downstream of the blockages also contributes to the disease.

How CTEPH is diagnosed

Diagnosis requires confirmation of pulmonary hypertension and evidence of chronic clots after at least three months of effective anticoagulation.

The V/Q scan is the recommended screening test, as it is more sensitive than a standard CT scan for chronic clots. Each case is then reviewed by a multidisciplinary CTEPH team to decide which treatment suits the pattern of disease.

CTEPH treatment

Lifelong anticoagulation

All patients need lifelong blood-thinning treatment to prevent further clots. Warfarin is generally preferred in antiphospholipid syndrome, while other anticoagulants may be used in selected patients.

Pulmonary endarterectomy

Pulmonary endarterectomy (PEA) is the treatment of choice for patients whose blockages are surgically accessible. The organised clot is removed from the lining of the pulmonary arteries through open-heart surgery with a period of circulatory arrest. In experienced centres it can cure or greatly improve the condition.

Balloon pulmonary angioplasty

For patients whose blockages are in smaller vessels beyond surgical reach, or who are not fit for surgery, balloon pulmonary angioplasty (BPA) widens the narrowed arteries through a catheter in a series of staged sessions.

Medicines

Riociguat, a soluble guanylate cyclase stimulator, is approved for inoperable CTEPH or persistent pulmonary hypertension after surgery. Other targeted pulmonary hypertension medicines, such as macitentan or treprostinil, may be used in selected patients. Many patients benefit from a combination of these approaches.

Outlook and follow-up

With timely treatment, many people with CTEPH experience a substantial improvement in breathlessness and exercise capacity, and some return to near-normal activity after surgery. Without treatment, the condition tends to progress.

Follow-up includes regular review of symptoms, walk tests, NT-proBNP and echocardiography, together with careful management of anticoagulation and prompt attention to any bleeding.

When to seek urgent care

Seek emergency medical attention for fainting, sudden worsening of breathlessness, chest pain, coughing up blood, a new swollen and painful leg, or rapidly increasing ankle swelling. Patients on anticoagulants should also seek urgent care for black stools, vomiting blood, severe headache or any bleeding that does not stop.

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