Recent Advances in Pulmonary Embolectomy: What Surgeons Need to Know

Pulmonary embolectomy is a surgical intervention designed to remove a pulmonary embolism (PE), which is a life-threatening condition where a blood clot obstructs the pulmonary artery or one of its branches, leading to impaired blood flow to the lungs. This procedure is often reserved for cases where thrombolytic therapy is contraindicated or ineffective, and the patient's condition is deteriorating. As a critical intervention, pulmonary embolectomy requires thorough understanding and careful execution.

Indications for Pulmonary Embolectomy

Pulmonary embolectomy is indicated primarily in the following scenarios:

1. Massive Pulmonary Embolism: When a large embolus obstructs the main pulmonary artery or its branches, leading to hemodynamic instability, shock, or cardiac arrest. This situation requires immediate intervention to restore blood flow and oxygenation.
2. Failed Thrombolysis: In cases where thrombolytic therapy fails to dissolve the clot, or when it's contraindicated due to risks like severe bleeding, an embolectomy may be necessary.
3. Chronic Thromboembolic Pulmonary Hypertension (CTEPH): This condition arises from unresolved clots that lead to persistent pulmonary hypertension. Pulmonary embolectomy can be curative in selected patients with CTEPH.
4. Contraindications to Thrombolysis: Patients with recent surgery, active bleeding, or hemorrhagic stroke are not candidates for thrombolysis, making surgical embolectomy a viable alternative.
5. Right Ventricular Failure: Severe right ventricular dysfunction due to massive PE, with evidence of right heart strain, may necessitate surgical intervention to prevent further deterioration.

Preoperative Evaluation

A comprehensive preoperative evaluation is essential for patients undergoing pulmonary embolectomy. This evaluation includes:

1. Imaging Studies:
   • CT Pulmonary Angiography (CTPA): The gold standard for diagnosing PE, CTPA provides detailed images of the pulmonary arteries, helping to localize the embolus.
   • Echocardiography: Used to assess right ventricular function and estimate pulmonary artery pressures. Echocardiography can also detect signs of right heart strain.
   • Ventilation-Perfusion (V/Q) Scan: An alternative to CTPA for patients with contraindications to iodinated contrast.
2. Laboratory Tests:
   • Coagulation Profile: Essential to assess bleeding risk, especially in patients with contraindications to anticoagulation.
   • Cardiac Biomarkers: Elevated levels of troponins and brain natriuretic peptide (BNP) can indicate myocardial strain and serve as markers for the severity of PE.
3. Cardiac Catheterization: In cases of CTEPH, right heart catheterization is crucial for assessing pulmonary artery pressures and determining surgical candidacy.
4. Pulmonary Function Tests (PFTs): These tests evaluate lung function and help predict postoperative outcomes, particularly in patients with underlying lung disease.
5. Assessment of Comorbidities: Evaluation of coexisting conditions such as coronary artery disease, chronic obstructive pulmonary disease (COPD), and renal insufficiency is vital to minimize perioperative risks.

Contraindications

Pulmonary embolectomy, though life-saving, is not without risks. Contraindications include:

1. Poor Surgical Candidates: Patients with severe comorbidities that make them high-risk for surgery may not be ideal candidates.
2. End-Stage Pulmonary Disease: Patients with advanced lung disease may not tolerate the procedure or the postoperative recovery.
3. Severe Right Heart Failure: In some cases, extreme right ventricular dysfunction may lead to poor surgical outcomes, and alternative therapies might be considered.
4. Non-viable Embolus: If the embolus is not accessible or the patient has chronic fibrotic changes, surgical intervention may not be beneficial.

Surgical Techniques and Steps

Pulmonary embolectomy can be performed using various approaches, with the choice depending on the patient's condition, the location of the embolus, and the surgeon's expertise.

1. Open Pulmonary Embolectomy

This traditional approach involves a sternotomy and cardiopulmonary bypass (CPB). The steps are as follows:

• Patient Positioning: The patient is placed in the supine position, and general anesthesia is administered.
• Sternotomy: A midline sternotomy is performed to access the heart and pulmonary arteries.
• Cannulation and CPB Initiation: Cannulation of the aorta and right atrium is done to initiate CPB, allowing for cardiac and pulmonary arrest.
• Pulmonary Arteriotomy: The main pulmonary artery is incised to expose the embolus.
• Embolectomy: The embolus is carefully extracted using surgical forceps. If the clot extends into the pulmonary branches, additional arteriotomies may be required.
• Closure and Weaning from CPB: The arteriotomy is closed, CPB is gradually weaned off, and the sternotomy is closed in layers.

2. Minimally Invasive Pulmonary Embolectomy

Minimally invasive approaches are gaining popularity due to reduced postoperative pain, shorter hospital stays, and quicker recovery times. Techniques include:

• Video-Assisted Thoracoscopic Surgery (VATS): Small incisions are made, and a thoracoscope is used to visualize the pulmonary arteries. The embolus is then removed using endoscopic instruments.
• Catheter-Directed Embolectomy: This technique involves using a catheter inserted through the femoral or jugular vein to reach the embolus. Various devices, such as aspiration catheters or mechanical thrombectomy tools, are used to remove the clot.

Postoperative Care

Postoperative management focuses on monitoring for complications, ensuring adequate anticoagulation, and supporting recovery.

1. Intensive Care Monitoring: Patients are typically transferred to the intensive care unit (ICU) for close monitoring of vital signs, oxygenation, and hemodynamics.
2. Anticoagulation Therapy: Lifelong anticoagulation is recommended to prevent recurrence. Warfarin, direct oral anticoagulants (DOACs), or low-molecular-weight heparin (LMWH) may be used.
3. Pulmonary Rehabilitation: Early mobilization and pulmonary rehabilitation are crucial to prevent atelectasis, pneumonia, and other pulmonary complications.
4. Ventilatory Support: Some patients may require temporary ventilatory support postoperatively, particularly those with preexisting pulmonary disease.
5. Fluid Management: Careful fluid management is essential to avoid fluid overload, which can exacerbate right ventricular failure.
6. Pain Management: Adequate pain control is vital for recovery, and multimodal analgesia is often employed.

Possible Complications

While pulmonary embolectomy can be life-saving, it carries the risk of several complications:

1. Bleeding: Significant blood loss can occur, especially in open embolectomy, necessitating transfusions or re-exploration.
2. Right Ventricular Failure: Postoperative right ventricular dysfunction can occur due to residual pulmonary hypertension or myocardial damage.
3. Stroke: Embolism or air embolism during surgery can lead to ischemic stroke.
4. Infection: Surgical site infections, pneumonia, and sepsis are potential complications, particularly in patients with prolonged ICU stays.
5. Recurrent Pulmonary Embolism: Despite successful embolectomy, recurrence is possible, emphasizing the need for lifelong anticoagulation.
6. Arrhythmias: Cardiac arrhythmias, particularly atrial fibrillation, may develop postoperatively due to myocardial strain or electrolyte imbalances.

Different Techniques

Different surgical techniques may be employed depending on the clinical scenario:

1. Direct Extraction: This involves the manual removal of the clot through arteriotomy.
2. Fogarty Catheter Embolectomy: A Fogarty balloon catheter is inserted into the pulmonary artery, inflated, and then withdrawn, pulling the clot with it.
3. Ultrasound-Assisted Embolectomy: Ultrasound waves are used to fragment the clot, making it easier to extract through a catheter.
4. Percutaneous Mechanical Thrombectomy: This involves using devices like the AngioVac system, which can aspirate the clot without requiring open surgery.

Prognosis and Outcome

The prognosis after pulmonary embolectomy depends on several factors, including:

1. Timing of Surgery: Early intervention in cases of massive PE is associated with better outcomes.
2. Right Ventricular Function: Preservation of right ventricular function is critical for a favorable prognosis.
3. Underlying Health: Patients with fewer comorbidities tend to recover better.
4. Complications: The presence of complications such as infection, bleeding, or recurrent embolism can worsen outcomes.

Overall, with prompt and appropriate intervention, the prognosis for patients undergoing pulmonary embolectomy can be excellent, with many patients experiencing significant improvements in symptoms and quality of life.

Alternative Options

For patients who are not candidates for pulmonary embolectomy, alternative treatments may include:

1. Catheter-Directed Thrombolysis: This involves delivering thrombolytic agents directly to the site of the clot through a catheter, reducing the risk of systemic bleeding.
2. IVC Filter Placement: Inferior vena cava (IVC) filters may be placed to prevent recurrent emboli from reaching the lungs, especially in patients with contraindications to anticoagulation.
3. Pharmacomechanical Thrombectomy: A combination of thrombolysis and mechanical clot disruption can be used in patients who are not surgical candidates.
4. Long-Term Anticoagulation: For patients with chronic PE, long-term anticoagulation may be sufficient to prevent progression and manage symptoms.

Average Cost

The cost of pulmonary embolectomy can vary widely depending on the country, healthcare facility, and the patient's insurance coverage. In the United States, the cost may range from $50,000 to $100,000, including surgery, hospitalization, and postoperative care. In other countries, costs may be lower, but factors like surgeon expertise and facility quality should be considered.

Recent Advances

Recent advances in pulmonary embolectomy include:

1. Hybrid Approaches: Combining open surgery with catheter-based techniques to minimize invasiveness and improve outcomes.
2. Advanced Imaging: The use of 3D imaging and intraoperative ultrasound to guide the surgical procedure with greater precision.
3. Robotic-Assisted Surgery: Emerging technologies in robotic surgery are being explored to perform pulmonary embolectomy with greater precision and less trauma.
4. Pharmacological Adjuncts: Newer anticoagulants and antiplatelet agents are being integrated into postoperative care to reduce the risk of recurrence.

Conclusion

Pulmonary embolectomy remains a critical surgical intervention for patients with life-threatening pulmonary embolism. With advances in surgical techniques, imaging, and postoperative care, the procedure continues to evolve, offering hope to patients who would otherwise face a grim prognosis. However, the success of pulmonary embolectomy depends on careful patient selection, timely intervention, and meticulous surgical execution.