PTE surgery, or pulmonary thromboendarterectomy, is an operation to remove old, scarred blood clots from the arteries in your lungs. It is the only potentially curative treatment for a condition called chronic thromboembolic pulmonary hypertension (CTEPH), where clots that never fully dissolved become embedded in the artery walls and permanently restrict blood flow. At high-volume centers performing more than 50 of these surgeries per year, the mortality rate is around 3.4%, and nearly 89% of patients are alive five years later.
The Condition PTE Surgery Treats
CTEPH develops when blood clots, usually from the legs or pelvis, travel to the lungs and never fully break down. Over months or years, these clots become incorporated into the artery walls, thickening and scarring them. The result is a permanent narrowing of the pulmonary arteries that forces the right side of the heart to pump much harder than normal. Left untreated, CTEPH leads to progressive right heart failure.
Most people with CTEPH experience severe shortness of breath and exercise intolerance. Before surgery, the majority of patients are significantly limited, with most classified as having advanced heart failure symptoms (New York Heart Association class III or IV, meaning symptoms at minimal exertion or at rest). Standard blood-thinning medications can prevent new clots but cannot remove the organized scar tissue already fused to the artery walls. That’s where PTE surgery comes in.
How the Surgery Works
PTE is not simply pulling out a clot. It is a true endarterectomy: surgeons peel away the inner lining of the pulmonary arteries along with the embedded scar tissue, following a dissection plane deep into the branching vessels of both lungs. The goal is to clear every affected segment of the pulmonary vascular tree so blood can flow freely again.
The operation requires the chest to be opened through the breastbone. The patient is placed on a heart-lung bypass machine, and the body is cooled to approximately 18°C (about 64°F). At that temperature, surgeons can temporarily stop all circulation for up to 20 minutes at a time. This deep hypothermic circulatory arrest creates a bloodless surgical field, which is essential because back-bleeding from smaller arteries would otherwise obscure visibility in the tiny vessels being cleared. An ice covering is placed around the head for brain protection during these periods.
Each lung is addressed separately. The surgeon opens the pulmonary artery on one side, identifies the correct tissue plane, and carefully follows it outward to the segmental branches. Once one side is complete, circulation is restored for at least 10 minutes to let the body recover before the other side is addressed. After both lungs are cleared, the patient is gradually rewarmed and weaned off the bypass machine.
Who Qualifies for PTE
Not every CTEPH patient is a surgical candidate. Eligibility depends on several factors: the severity of symptoms, the degree of right heart strain and elevated lung pressures, and most critically, where the clot material sits in the artery tree. Surgeons classify disease into four levels based on how far from the main arteries the blockages begin. Levels I and II, where clots start in the main or lobar arteries, are the most straightforward to operate on. Level III disease, starting at the segmental branches, is more challenging but still operable at experienced centers. Level IV, where disease is limited to the smallest subsegmental vessels, is generally considered too distal for surgery to reach.
Diagnosis typically involves specialized imaging to map the location and extent of clot material. Patients whose disease is too peripheral for surgery, or who have other serious medical conditions making the operation too risky, may be offered balloon pulmonary angioplasty (BPA) instead. In one large center’s experience, about 59% of patients directed to BPA had disease that was simply too far out in the lung vasculature for a surgeon to clear. Another 21% had already undergone PTE but had residual disease. Only 3% of BPA patients had operable disease but chose not to have surgery.
What the Surgery Achieves
The hemodynamic improvements after successful PTE are dramatic and often immediate. In one study of 72 patients, average pulmonary artery pressure dropped from 42 mmHg before surgery to 22 mmHg afterward. A key marker of heart strain, measured through a blood test (NT-proBNP), fell from roughly 1,527 to 160. The distance patients could walk in six minutes jumped from 359 meters to 518 meters, an improvement of nearly 45%.
Perhaps the most meaningful outcome for patients: almost everyone moved from severe functional limitation to mild or no limitation. Before surgery, the vast majority were in heart failure classes III and IV. Afterward, nearly all returned to class I or II, meaning they could go about daily activities without significant breathlessness.
Reducing the resistance in the pulmonary arteries by at least 50% is a critical threshold. Patients who achieve that reduction have meaningfully better long-term survival than those who don’t.
Risks and Complications
PTE is a major operation with real risks. The two most significant complications are reperfusion pulmonary edema and right heart failure. Reperfusion edema occurs when blood suddenly floods into lung tissue that has been starved of normal flow for months or years, causing fluid to leak into the air spaces. Right heart failure can occur if the surgery doesn’t reduce pressures enough, or if the heart muscle has been weakened too much before surgery.
Reported mortality ranges from about 5% to 24% depending on the center. This wide range is largely a matter of surgical volume. Centers performing more than 100 PTE surgeries annually report mortality as low as 2.9%. Those performing 16 to 50 per year average 6.7%. The lowest-volume centers have rates exceeding 11%. This makes center selection one of the most important decisions in the process.
Recovery After PTE
Recovery begins in the intensive care unit, where patients are monitored closely for the complications described above, particularly in the first few days when reperfusion edema is most likely to appear. Most patients spend several days in the ICU before moving to a regular hospital floor.
Because the body was cooled so profoundly during surgery and the chest was opened through the sternum, the early recovery period involves regaining strength gradually. Patients typically notice improved breathing relatively quickly, sometimes within the first few weeks, though full recovery takes longer. The sternal bone needs about six to eight weeks to heal, similar to other open-heart procedures, and patients are advised to avoid heavy lifting during that period.
Long-term, patients remain on blood-thinning medication indefinitely to prevent new clots from forming. Follow-up imaging and pressure measurements help confirm that the surgery achieved adequate clearance and that the right side of the heart is recovering.
PTE Surgery vs. Balloon Pulmonary Angioplasty
BPA is a catheter-based alternative where tiny balloons are threaded into the pulmonary arteries and inflated to widen narrowed vessels. It does not remove the scar tissue, and it is not considered curative. Current guidelines position BPA as a treatment for patients who cannot have PTE or who have residual high pressures after PTE. Patients selected for BPA tend to have milder disease overall, with lower baseline pulmonary pressures and resistance compared to surgical candidates. For patients with accessible disease and acceptable surgical risk, PTE remains the preferred treatment because of its potential to normalize lung pressures in a single procedure.