Illustration of lungs transitioning from blocked to clear, symbolizing improved perfusion after PTE.

Clearing the Airways: How Improved Perfusion Scoring is Revolutionizing Pulmonary Thromboendarterectomy

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Beau Callahan in Health & Wellness October 2026 • 5 min read.

"Discover how a novel method of perfusion scoring after pulmonary thromboendarterectomy (PTE) is leading to better outcomes for patients, improving hemodynamic and right heart function."


Pulmonary thromboendarterectomy (PTE) is a critical surgical procedure for patients suffering from chronic thromboembolic pulmonary hypertension (CTEPH), where blood clots obstruct pulmonary arteries, leading to increased pressure and strain on the heart. The success of PTE hinges not only on the physical removal of these clots but also on the subsequent improvement in blood flow, or perfusion, to the affected lung segments.

A study presented at the American College of Cardiology's 67th Annual Scientific Session (ACC.18) explored a novel method for evaluating perfusion improvement after PTE. This research highlights the correlation between enhanced perfusion scoring and tangible improvements in patients' clinical condition, hemodynamic parameters, and right heart function.

This article will delve into the methods and findings of this study, explaining how this perfusion scoring technique can optimize post-PTE management and contribute to better patient outcomes. We'll break down the complexities of the research in an accessible way, focusing on what it means for those affected by CTEPH and the healthcare professionals who treat them.

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Outcomes and Ongoing Impact

Reported 30-day mortality after pulmonary thromboendarterectomy ranges from 0.8% to 24.4%, with a meta-analysis estimating 8.4% mortality (95% CI, 7.2–9.6%). A 2025 review reports mortality of 1% to 2% at expert centers and describes excellent long-term survival. One study found survival rates of 97% at 1 year, 90.4% at 5 years, and 79% at 8 years after PTE. About 10% to 15% of patients may still have pulmonary hypertension after surgery, although many report feeling substantially better.

A Complex, Standardized Operation

Pulmonary endarterectomy is a complex but standardized procedure intended to completely clear obstructed pulmonary arteries. The operation is considered potentially curative for chronic thromboembolic pulmonary hypertension, but patient selection is important. Severe emphysema or interstitial lung disease is described as an important contraindication because affected patients are less likely to benefit. Operative technique also requires removal of loose or bulky proximal pulmonary-artery thrombus before the endarterectomy can be properly performed.

From Embolectomy to Curative Surgery

Moser emphasized that technical advances enabling emergency pulmonary embolectomy and open-heart surgery also made pulmonary thromboendarterectomy feasible for selected patients with massive pulmonary-artery occlusion. Chronic thromboembolic obstruction of the major pulmonary arteries can follow acute pulmonary embolism, although its prevalence is likely underestimated. PTE became distinguished as a conservative surgical treatment capable of successfully treating a form of pulmonary hypertension. More recent technical advances have extended endarterectomy to distal disease while reporting comparable outcomes.

Unlocking the Science: Perfusion Scoring and PTE Outcomes

Illustration of lungs transitioning from blocked to clear, symbolizing improved perfusion after PTE.

The study, led by researchers from Temple University Hospital and Weill Cornell Medical Center, involved 37 patients who underwent PTE. These patients underwent ventilation/perfusion (VQ) scans before and after the surgery to assess blood flow in the lungs. The VQ scans were conducted using planar and SPECT/CT techniques, providing detailed images of lung perfusion.

A perfusion scoring system was used to quantify the degree of blood flow in different lung segments. Each segment was evaluated across multiple projections, with a total possible score of 68. Deficits in perfusion were graded as severe (1), moderate (2), mild (3), or none (4). Clinical and hemodynamic data were collected to compare pre- and post-PTE results.

  • NYHA Functional Class: Improved from 3±1 to 2±1 (p<0.05), indicating reduced symptoms and better exercise capacity.
  • Cardiac Index: Increased from 2.1±0.6 to 2.8±0.5 L/min/m² (p<0.05), reflecting improved heart function and cardiac output.
  • Pulmonary Vascular Resistance: Decreased significantly from 8.5±5.3 to 2.2±1.1 mmHg/L/min (p<0.05), demonstrating reduced pressure in the pulmonary arteries.
  • Right Ventricle Function: The ratio of right ventricle to left ventricle size improved from 1.1±0.3 to 0.9±0.2 (p<0.05), and the right ventricular fractional area change increased from 28±14% to 46±11% (p<0.05), indicating enhanced right heart performance.
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Evidence for Durable Benefit

Recent reviews continue to identify pulmonary thromboendarterectomy as the gold-standard treatment for chronic thromboembolic pulmonary hypertension. A systematic review reports improved health-related quality of life at 3 months, with benefits that are sustained. Research on repeat PTE also concludes that the procedure may be an appropriate, safe, and effective option for selected patients with recurrent CTEPH or an incomplete initial operation.

Risks of Recurrence and Residual Disease

Repeat pulmonary thromboendarterectomy has been associated with increased risks of postoperative bleeding, reperfusion lung injury, and residual pulmonary hypertension. The underlying disease can block blood flow to the lungs, cause vascular damage and pulmonary hypertension, and progress to heart failure without treatment. Research has also examined limitations of resting hemodynamics in chronic thromboembolic disease without pulmonary hypertension, including circumstances involving failure of pulmonary endarterectomy.

PEA Compared With Alternatives

A 2023 comparison confirmed the superiority of pulmonary endarterectomy over alternative treatment strategies in patients with CTEPH. The same analysis observed that balloon pulmonary angioplasty may be useful for patients considered unsuitable for surgery. This comparison supports matching treatment selection to operability rather than treating PEA and BPA as interchangeable options.

The researchers divided the patients into two groups based on when the post-PTE VQ scan was performed: a 'late' VQ group (30 patients, scan at 3 months) and an 'early' VQ group (7 patients, scan at 1 week). The late VQ group showed a significant improvement in perfusion scores (43±7 to 55±7, p<0.05). While the early VQ group also showed improvement, it was not as significant (55±7 vs 50±8, p=0.06). Notably, improvements in clinical and hemodynamic parameters were similar in both groups, suggesting that perfusion continues to improve over time.

The Future of PTE: Optimizing Perfusion Assessment

This study underscores the importance of perfusion scoring as a valuable tool in assessing the effectiveness of PTE. By quantifying the improvement in blood flow to the lungs, clinicians can gain a more objective understanding of the surgery's success and tailor post-operative management accordingly.

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The Best Chance for Eligible Patients

Pulmonary endarterectomy is considered the best and only curable treatment option for patients with accessible lesions who are evaluated as optimal candidates. Expert reviews state that PEA offers the best chance of symptomatic and prognostic improvement in eligible patients. Other expert commentary likewise describes PEA as the gold-standard therapy for CTEPH and associates it with improved clinical and survival outcomes.

Expanding Access and Capability

Untreated CTEPH has been associated with poor prognosis; one cited report places 5-year survival at 30% among patients with mean pulmonary arterial pressure in the referenced high-risk setting. Yale Medicine reports a 96% success rate for pulmonary thromboendarterectomy, defined as significant symptom improvement, and notes that many patients are cured. Separately, a market analysis projects a 6.8% compound annual growth rate for the pulmonary endarterectomy market from 2024 through 2030.

A High-Stakes Specialized Procedure

Stanford Health Care describes pulmonary thromboendarterectomy as advanced surgery used to remove chronic blood clots and scar tissue from the arteries of the lungs. The description underscores that PTE is not a routine intervention but a specialized operation for chronic obstructive pulmonary disease in the pulmonary arteries. Its advanced nature makes appropriate evaluation and surgical expertise central to delivering its potential benefits.

Recovery Beyond the Operating Room

A Cleveland Clinic case study reports that even patients with the most severe CTEPH may be cured with pulmonary thromboendarterectomy and suggests that very few patients do not stand to benefit. An editorial on the procedure describes dramatic improvements in hemodynamics and an association with improved survival. Initial Portuguese experience also reported good survival and functional recovery among treated patients, although three late deaths occurred.

The research suggests that assessing perfusion at three months post-PTE provides a reliable indicator of long-term outcomes. Further studies could explore the optimal timing for perfusion assessment and investigate the relationship between perfusion scores and other clinical markers.

For patients with CTEPH, this research offers hope for improved outcomes and a better quality of life. By optimizing perfusion assessment and tailoring treatment strategies, healthcare professionals can continue to refine the PTE procedure and enhance the well-being of those affected by this challenging condition.

Putting pulmonary perfusion changes in context

  • 8% and 7%After pulmonary endarterectomy, whole-lung perfusion defect percentage fell by 8% on CT and 7% on dynamic contrast-enhanced MRI; both changes were statistically significant.[1]

What perfusion measurements add

The pressure changes varied with the level of arterial disease, so the extent and location of obstruction matter when interpreting post-operative hemodynamic change. The separate finding on vascular steal also suggests that reduced pressure can coincide with improvement in blood supply to previously affected segments; it does not show that every perfusion abnormality resolves.[2] [3]

Even when resting heart and pressure measures normalize after surgery, exercise intolerance may remain common. Thus, resting measures and perfusion imaging do not by themselves describe every aspect of recovery during activity.[4]

What remains unresolved about post-operative perfusion

  • How well do resting hemodynamics and perfusion measures capture recovery when exercise intolerance can persist despite normalized resting measures?[4]
  • Can preoperative pressure and V/Q mismatch distinguish patients at risk of persistent or recurrent pulmonary hypertension in populations beyond the analysis that reported their association with survival time?[5] [6]
  • How should post-operative vascular steal be interpreted alongside perfusion defects and small-vessel changes, given the proposed link between relief of pulmonary hypertension and resolution of steal?[3]

Sources

  1. Comparison of dual-energy computer tomography and dynamic contrast-enhanced MRI for evaluating lung perfusion defects in chronic thromboembolic pulmonary hypertension (pmc.ncbi.nlm.nih.gov)
  2. Dual-Energy CT Pulmonary Angiography for the Assessment of Surgical Accessibility in Patients with Chronic Thromboembolic Pulmonary Hypertension (pmc.ncbi.nlm.nih.gov)
  3. Resolution of vascular steal after pulmonary thromboendarterectomy. (pubmed.ncbi.nlm.nih.gov)
  4. Right Ventricular Function During Exercise After Pulmonary Endarterectomy for Chronic Thromboembolic Pulmonary Hypertension (pmc.ncbi.nlm.nih.gov)
  5. The Predictive Value of Quantitative Analysis of SPECT V/Q Imaging for Postoperative Persistent/Recurrent Pulmonary Hypertension in Patients With Chronic Thromboembolic Pulmonary Hypertension After Pu (pmc.ncbi.nlm.nih.gov)
  6. Residual pulmonary hypertension after pulmonary endarterectomy: A meta-analysis. (pubmed.ncbi.nlm.nih.gov)

About this Article -

Written with AI assistance from published research, and reviewed by the Mystum team. See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/s0735-1097(18)32239-3, Alternate LINK

Title: Improvement In Perfusion Scoring After Pulmonary Thromboendarterectomy Correlates With Improvement In Clinical: Hemodynamic And Right Heart Function

Subject: Cardiology and Cardiovascular Medicine

Journal: Journal of the American College of Cardiology

Publisher: Elsevier BV

Authors: Farhan Raza, Anjali Vaidya, Chandra Dass, Paul Forfia, Simin Dadparvar

Published: 2018-03-01

Everything You Need To Know

1

What is pulmonary thromboendarterectomy (PTE) and why is it performed?

Pulmonary thromboendarterectomy, or PTE, is a surgical procedure performed to treat chronic thromboembolic pulmonary hypertension, also known as CTEPH. In CTEPH, blood clots obstruct the pulmonary arteries, which increases pressure and strain on the right side of the heart. PTE involves the physical removal of these clots to restore blood flow and reduce pulmonary hypertension. The success of PTE depends on how well blood flow (perfusion) is restored to the lungs after surgery.

2

How did the researchers in the ACC.18 study evaluate perfusion improvement after pulmonary thromboendarterectomy (PTE)?

The study presented at ACC.18 used ventilation/perfusion (VQ) scans before and after PTE to evaluate blood flow in the lungs. These VQ scans used planar and SPECT/CT techniques to create detailed images of lung perfusion. Researchers then used a perfusion scoring system to quantify the degree of blood flow in different lung segments, evaluating each segment across multiple projections, with deficits graded on a scale. Clinical and hemodynamic data were collected to compare pre- and post-PTE results, measuring metrics such as NYHA Functional Class, Cardiac Index, Pulmonary Vascular Resistance, and Right Ventricle Function.

3

In the ACC.18 study, what differences were observed between the 'early' and 'late' VQ scan groups after pulmonary thromboendarterectomy (PTE)?

The study divided patients into two groups based on when they received the post-PTE VQ scan: an 'early' VQ group (scan at 1 week) and a 'late' VQ group (scan at 3 months). While both groups showed improvement in perfusion scores, the 'late' VQ group had a more significant increase. Importantly, improvements in clinical and hemodynamic parameters were similar in both groups, suggesting that perfusion continues to improve over time, even beyond the first week post-surgery. The results highlight the importance of longer-term monitoring to fully assess the benefits of PTE.

4

What specific clinical and hemodynamic improvements were observed in patients with enhanced perfusion scoring after pulmonary thromboendarterectomy (PTE)?

Improvements in perfusion scoring after PTE are associated with improvements in several key clinical and hemodynamic parameters. For example, patients saw improvement in NYHA Functional Class, indicating reduced symptoms and better exercise capacity. Their Cardiac Index increased, reflecting improved heart function and cardiac output. Pulmonary Vascular Resistance decreased significantly, demonstrating reduced pressure in the pulmonary arteries. Additionally, right ventricle function improved, as indicated by the ratio of right ventricle to left ventricle size and the right ventricular fractional area change.

5

What are the potential implications of using perfusion scoring to assess the effectiveness of pulmonary thromboendarterectomy (PTE) and what further research could be conducted?

This study demonstrates how perfusion scoring can be a valuable tool in assessing the effectiveness of PTE. By quantifying improvements in blood flow to the lungs, clinicians gain a more objective understanding of the surgery's success. This allows for tailoring post-operative management strategies and provides a basis for further research into optimizing PTE outcomes. Future research could investigate the optimal timing for VQ scans, refine the perfusion scoring system, and explore additional interventions to maximize perfusion improvement after PTE. The study supports the role of perfusion scoring in clinical practice, but more research is needed to fully realize its potential.

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