Chronic Thromboembolic Pulmonary Hypertension (CTEPH)

Diagnosing CTEPH can be challenging due to the non-specific nature of its symptoms, which often overlap with those of other forms of pulmonary hypertension and cardiopulmonary conditions. Symptoms such as progressive dyspnea on exertion, fatigue, and sometimes hemoptysis, are common. Early and precise diagnosis is crucial, as CTEPH is potentially curable.

Diagnostic Approach

• Clinical Suspicion: CTEPH should be suspected in patients with unexplained pulmonary hypertension, particularly those with a history of pulmonary embolism or deep vein thrombosis (DVT).
• Screening and Non-Invasive Testing: The initial evaluation typically includes transthoracic echocardiography, which may show signs of right ventricular hypertrophy or dysfunction, and elevated pulmonary artery pressures.
• Ventilation/Perfusion (V/Q) Scan: The V/Q scan is considered the gold standard screening test for CTEPH. Patients with CTEPH typically demonstrate multiple segmental mismatched perfusion defects.
• CT Pulmonary Angiography (CTPA): CTPA can help visualize organized thrombi, webs, or stenoses in the pulmonary arteries, and is useful for surgical planning.
• Pulmonary Angiography: This remains the definitive diagnostic method, providing detailed information about the location and extent of vascular obstructions. It is also essential for planning interventions such as PEA and BPA.
• Right Heart Catheterization: This invasive test is necessary to document pulmonary hypertension and assess hemodynamics, including mean pulmonary artery pressure and pulmonary vascular resistance.

The ideal management of CTEPH comprises a multidisciplinary approach, typically involving pulmonary hypertension specialists, interventional radiologists, and cardiothoracic surgeons. The main treatment options are pulmonary endarterectomy (PEA), balloon pulmonary angioplasty (BPA), and targeted medical therapy.

Pulmonary Endarterectomy (PEA)

PEA is the gold standard and potentially curative surgical treatment for CTEPH. It involves the removal of organized thromboembolic material from the pulmonary arteries through open-heart surgery under deep hypothermic circulatory arrest. Key points about PEA:

• Indications: Suitable for patients with surgically accessible, proximal thromboembolic disease.
• Outcomes: PEA can dramatically improve or normalize pulmonary hemodynamics, symptoms, and survival; post-operative mortality in experienced centers is less than 5%.
• Risks and Limitations: Not all patients are eligible; inoperability may be due to distal lesions, comorbidities, or patient choice.

Balloon Pulmonary Angioplasty (BPA)

BPA is a minimally invasive, catheter-based procedure indicated for patients with inoperable CTEPH or persistent/recurrent pulmonary hypertension after pulmonary endarterectomy (PEA). During BPA, a balloon-tipped catheter is advanced under fluoroscopic guidance into affected segments of the pulmonary arteries, where it is inflated to dilate stenotic or obstructed vessels.

• Indications: For patients not suitable for PEA, especially with distal, segmental, or subsegmental disease.
• Efficacy: BPA has demonstrated significant improvements in pulmonary hemodynamics, exercise capacity, and symptom burden.
• Risks: Complications may include pulmonary artery injury or reperfusion pulmonary edema, but procedural refinements have reduced these risks.
• Repeatability: BPA is often performed as a series of staged sessions to optimize safety and effectiveness.

Medical Therapy

Medical therapy is generally reserved for:

• Patients who are not candidates for PEA or BPA
• Those with persistent or recurrent pulmonary hypertension following surgery or intervention

Options include:

• Riociguat: The only approved medication for CTEPH, it improves exercise capacity and pulmonary vascular resistance.
• Other Targeted Therapies: Endothelin receptor antagonists, phosphodiesterase type 5 inhibitors, and prostacyclin analogues may be considered in selected cases, often off-label.

In all patients, lifelong anticoagulation is recommended to prevent recurrent thromboembolic events.

• Oxygen therapy for hypoxemia
• Diuretics for right heart failure
• Rehabilitation and exercise programs