Pulmonary Endarterectomy
Pulmonary endarterectomy is the definitive, potentially curative surgical treatment for chronic thromboembolic pulmonary hypertension (CTEPH), involving the removal of organized thromboembolic material from the pulmonary arterial tree to normalize pulmonary hemodynamics and improve right ventricular function. 1, 2
Definition and Procedure
- Pulmonary endarterectomy (PTE) is a true endarterectomy (not an embolectomy) that removes organized and incorporated fibrous obstructive thromboembolic material from the pulmonary arterial tree 3
- The procedure is performed via median sternotomy on cardiopulmonary bypass with deep hypothermia and periods of complete circulatory arrest to provide adequate visibility 1
- The main pulmonary arteries are incised, and the endarterectomy plane is followed circumferentially down to segmental and sometimes subsegmental branches of each lobar artery using special suction dissectors 1
Patient Selection and Operability
Patients with CTEPH should be promptly evaluated for pulmonary endarterectomy at an experienced center, even if symptoms are mild (Class I; Level of Evidence B) 1
Selection criteria include:
- New York Heart Association (NYHA) functional class III or IV symptoms
- Preoperative pulmonary vascular resistance greater than 300 dyn·s·cm⁻⁵
- Surgically accessible thrombi in main, lobar, or segmental pulmonary arteries
- Absence of severe comorbidity 1
There is no upper limit of pulmonary vascular resistance (PVR) or degree of right ventricular dysfunction that absolutely excludes a patient from surgery at experienced centers 1
Advanced age (≥80 years), renal insufficiency, and hepatic dysfunction are not absolute contraindications but do affect risk 1
Classification of CTEPH Lesions
Patients can be postoperatively classified into four categories based on lesion location:
- Type 1: Fresh thrombus in the main lobar pulmonary arteries 1
- Type 2: Thickening and fibrosis of the intima proximally to the segmental arteries 1
- Type 3: Involvement of distal segmental arteries only 1
- Type 4: Distal arteriolar involvement without visible thromboembolic disease 1
Outcomes and Benefits
- Perioperative mortality is related to disease severity:
- 4% in patients with preoperative PVR <900 dyn·s·cm⁻⁵
- 20% in those with PVR >1200 dyn·s·cm⁻⁵ 1
- At experienced centers performing >50 procedures annually, mortality rates are <5% 4
- Pulmonary endarterectomy reduces mean pulmonary artery pressure by approximately 21 mmHg and PVR by about 561 dyn·s·cm⁻⁵ 5
- Functional results are excellent and generally sustained over time:
Common Challenges and Pitfalls
- Approximately 25% of patients experience persistent pulmonary hypertension after pulmonary endarterectomy 5
- The preoperative differentiation of operable from inoperable CTEPH remains problematic and depends on:
- Surgical expertise
- Degree of microvascular disease present
- Relative contribution of microvascular disease to overall PVR 1
- Patients with significant pulmonary hypertension but little visible thromboembolic pathology are poor candidates for surgery 1
- CTEPH is significantly underdiagnosed despite affecting approximately 4-5% of patients who have had acute pulmonary embolism 6
Post-Operative Management
- Patients with CTEPH should receive indefinite therapeutic anticoagulation after surgery in the absence of contraindications (Class I; Level of Evidence C) 1
- PAH-specific medical therapy may be considered for patients with residual pulmonary hypertension after operation 1
- Complications include reperfusion lung injury and persistent pulmonary hypertension 7
Pulmonary endarterectomy remains the gold standard treatment for CTEPH, providing immediate correction of hemodynamic parameters in most patients and offering superior outcomes compared to lung transplantation for this condition 1, 4.