Pulmonary Endarterectomy (PEA) is a complex surgical procedure aimed at treating chronic thromboembolic pulmonary hypertension (CTEPH). This condition involves the obstruction of the pulmonary arteries due to organized blood clots (thromboemboli) that prevent proper blood flow to the lungs, leading to high blood pressure in the pulmonary arteries and potentially severe heart failure.

CTEPH is often a result of unresolved or incompletely treated pulmonary embolism (PE), where blood clots travel to the lungs and cause blockages. Over time, these clots can organize and become fibrotic, leading to permanent narrowing of the pulmonary arteries. Pulmonary Endarterectomy is considered the gold standard surgical treatment for CTEPH, with the goal of removing the clots and restoring normal blood flow to the lungs.

Indications for Pulmonary Endarterectomy (PEA)

Pulmonary Endarterectomy is typically recommended for patients with CTEPH who:

• Have persistent pulmonary hypertension despite anticoagulation therapy (blood thinners).
• Are deemed suitable for surgery after assessment by a multidisciplinary team, including a pulmonary hypertension specialist and cardiothoracic surgeon.
• Do not have contraindications such as advanced right heart failure, severe comorbidities, or extensive distal (deep) thromboembolic disease that would make surgery ineffective.

Procedure Overview

1. Preoperative Assessment

Before PEA surgery, a thorough evaluation is performed to assess the severity of pulmonary hypertension, the location and extent of the clots, and the patient's overall health status. This typically includes:

• Right heart catheterization: Measures the pulmonary artery pressures and evaluates the severity of pulmonary hypertension.
• CT pulmonary angiography or ventilation-perfusion scan: Determines the location of the clots.
• Echocardiogram: Assesses the function of the right heart and the effect of pulmonary hypertension.
• Pulmonary function tests: Evaluates lung capacity and function.

The goal of these evaluations is to confirm that the patient is a good candidate for surgery and to help plan the surgical approach.

2. Surgical Approach

• General Anesthesia: The patient is placed under general anesthesia.
• Median Sternotomy: A vertical incision is made through the sternum to access the heart and lungs. In some cases, a clamshell incision (an incision that opens both sides of the chest) may be used.
• Cardiopulmonary Bypass (CPB): The patient is placed on a heart-lung machine to take over the function of the heart and lungs during the surgery. This allows the surgeon to operate on a bloodless field and control blood flow to the lungs.
• Exposing the Pulmonary Arteries: The surgeon carefully exposes the main pulmonary arteries and their branches to identify the clot. The obstructed arteries are carefully dissected to remove all the organized thrombus (clot material).
• Endarterectomy: The surgeon meticulously removes the clotted material from the pulmonary arteries, often requiring a highly detailed dissection of the arterial wall. The goal is to clear the arteries as much as possible to restore normal blood flow.
• Post-Operative Monitoring: After the clot removal, the heart-lung machine is weaned off, and blood flow is restored through the newly cleared pulmonary arteries.

3. Postoperative Care

• ICU Care: After surgery, patients are closely monitored in an intensive care unit (ICU) for the first 24-48 hours.
• Right Heart Function: Monitoring of right heart function is critical as patients with CTEPH often have compromised right heart performance due to the chronic pulmonary hypertension.
• Ventilation and Oxygenation: Oxygen support may be required postoperatively.
• Pain Management: Proper pain control and respiratory support are essential during recovery.

Benefits of Pulmonary Endarterectomy

PEA can significantly improve symptoms and outcomes in patients with CTEPH:

• Reduction in Pulmonary Hypertension: Removing the obstructions in the pulmonary arteries can lower the pressures in the pulmonary circulation and improve right heart function.
• Improved Exercise Capacity: Patients often experience an improvement in physical stamina and exercise tolerance after the surgery.
• Increased Survival Rates: For patients with suitable anatomy and disease extent, PEA can significantly increase survival rates, often offering the only definitive cure for CTEPH.
• Quality of Life: Post-surgery, many patients experience a marked improvement in symptoms such as shortness of breath, fatigue, and chest pain.

Risks and Complications

While Pulmonary Endarterectomy is a life-saving procedure, it is highly complex and carries significant risks:

• Surgical Risks: As with any major surgery, there are risks of bleeding, infection, and wound complications.
• Pulmonary Hypertension Relapse: In some cases, the pulmonary hypertension may recur if residual thrombus remains or if the underlying cause of the clotting is not addressed.
• Right Heart Failure: The heart, especially the right ventricle, is vulnerable after the surgery, as it adjusts to the improved blood flow.
• Neurological Risks: There is a small risk of stroke or neurological complications due to the embolic nature of the disease or complications related to the use of the heart-lung machine.
• Hemorrhage: As the procedure involves major dissection and resection of the pulmonary vessels, bleeding complications may arise.

Postoperative Recovery and Long-Term Outlook

• Hospital Stay: Patients typically remain in the hospital for 1 to 2 weeks, depending on their recovery.
• Rehabilitation: Pulmonary rehabilitation may be recommended to help patients regain strength, improve lung function, and enhance quality of life.
• Follow-up Care: Regular follow-up with a cardiologist or pulmonologist is necessary to monitor heart and lung function.
• Medications: Blood thinners (anticoagulants) are typically continued postoperatively to prevent further clot formation. In some cases, pulmonary vasodilators may be prescribed.

Outcomes and Prognosis

• Success Rates: PEA has a high success rate for suitable patients, with improvements in symptoms, exercise capacity, and quality of life. Approximately 50-70% of patients experience significant benefits, including symptom resolution or substantial improvement.
• Long-term Survival: Studies show that 5-year survival rates for patients undergoing PEA range from 60% to 80%, depending on the severity of the disease, the presence of other comorbidities, and the effectiveness of the surgery.

Summary

Pulmonary Endarterectomy (PEA) is a highly specialized and effective surgical treatment for chronic thromboembolic pulmonary hypertension (CTEPH). It involves the removal of organized thrombus (clots) from the pulmonary arteries to restore normal blood flow and reduce pulmonary artery pressures. This procedure can significantly improve symptoms, exercise tolerance, and long-term survival in patients with CTEPH. However, it is a high-risk surgery that requires a careful preoperative assessment, precise surgical technique, and diligent postoperative care. When successful, PEA offers the potential for significant improvements in quality of life and survival, making it the gold standard treatment for CTEPH.