What does the pulmonologist mean by recommending catheter‑based thrombectomy for my pulmonary embolism given the large clot burden and borderline right ventricular systolic function?

Understanding the Pulmonologist's Recommendation for Catheter-Based Thrombectomy

Your pulmonologist recommended catheter-based thrombectomy because you have intermediate-risk (submassive) pulmonary embolism with a large clot burden and borderline right ventricular dysfunction—a situation where removing the clot directly can prevent right heart failure and potentially save your life, but the radiology team declined to perform the procedure, likely due to institutional protocols, resource availability, or differing risk assessment.

What This Means Clinically

Your situation falls into what guidelines classify as intermediate-risk PE with right ventricular (RV) strain 1. The "borderline right ventricular systolic function" means your right heart is struggling to pump blood through your lungs because of the clot burden blocking the pulmonary arteries. This puts you at risk for:

• Clinical deterioration and hemodynamic collapse
• Progression to high-risk PE requiring more aggressive interventions
• Long-term complications like chronic thromboembolic pulmonary hypertension

Why Thrombectomy Was Recommended

According to the most recent 2025 ACR guidelines, catheter-directed therapy (CDT)—which includes mechanical thrombectomy—is an appropriate treatment option for intermediate-risk PE with RV strain 1. The pulmonologist's reasoning was sound:

The Evidence Supporting This Approach:

• The FLARE trial demonstrated a 25% reduction in RV/LV ratio at 48 hours after catheter-based mechanical thrombectomy in intermediate-risk PE 1
• The FLASH registry showed significant improvements: 7.6 mm Hg drop in pulmonary artery pressure and improved RV/LV ratio (from 1.23 to 0.98) with favorable safety profile 1
• Matched cohort analysis of 470 patients showed lower 1-year mortality (7.6% vs 9.8%) with CDT plus anticoagulation compared to anticoagulation alone, with no difference in bleeding complications 1

The Goal of Thrombectomy:

The procedure aims to physically remove clot burden quickly to:

• Relieve the pressure on your right ventricle immediately
• Prevent progression to cardiogenic shock
• Improve outcomes beyond what anticoagulation alone can achieve

Why Radiology Declined

The radiology team's refusal likely stems from several factors:

1. Risk-benefit assessment differences: While guidelines support CDT for intermediate-risk PE, it carries a class IIa recommendation (meaning "reasonable to perform" but not universally mandated) 2

2. Institutional protocols: Many centers reserve these procedures for high-risk (hemodynamically unstable) patients or those actively deteriorating 3, 4

3. Resource and expertise considerations: CDT requires specialized equipment, training, and monitoring capabilities that may not be immediately available

4. Conservative approach: Since you're hemodynamically stable (no sustained hypotension), some practitioners prefer close monitoring with anticoagulation alone, intervening only if you deteriorate 3

What Should Happen Now

You should remain on therapeutic anticoagulation with close monitoring for signs of clinical deterioration 1. The 2019 AHA guidelines emphasize that if patients deteriorate (hemodynamically, respiratory status, or RV function), more intensive therapies including catheter-based embolectomy should be strongly considered 3.

Critical Warning Signs to Watch For:

• Worsening shortness of breath
• Chest pain
• Lightheadedness or syncope
• Dropping blood pressure (systolic <90 mm Hg)
• Increasing heart rate
• Decreasing oxygen saturation

The Clinical Dilemma:

There's a knowledge gap in current guidelines about which intermediate-risk patients truly benefit from immediate intervention versus close monitoring 3. The evidence shows:

• Anticoagulation alone is standard of care for intermediate-risk PE 1
• CDT improves short-term surrogate outcomes (RV function, clot burden) but long-term clinical outcome data remain limited 3
• Some patients deteriorate despite anticoagulation, requiring rescue therapy—but predicting who will deteriorate is imperfect 3

The Controversy

This represents a genuine area of clinical disagreement. Your pulmonologist took a more aggressive stance based on:

• Large clot burden
• Borderline RV function (suggesting you're on the edge of decompensation)
• Evidence that early intervention may prevent deterioration

The radiology team took a more conservative approach, likely reasoning:

• You're hemodynamically stable
• Anticoagulation is proven effective
• Procedural risks exist (bleeding, vascular injury, hemodynamic collapse during the procedure itself) 3

Both positions have merit in the current evidence landscape. The 2025 ACR guidelines acknowledge that catheter-directed mechanical thrombectomy is "usually appropriate" for your clinical scenario, but this doesn't make it mandatory 1.

Practical Next Steps

1. Ensure you're on appropriate anticoagulation (this is non-negotiable)
2. Request involvement of a multidisciplinary PE response team if your hospital has one 1, 3
3. Establish clear monitoring parameters with your care team for when to escalate therapy
4. Consider transfer to a center with PE response team capabilities if deterioration occurs and your current facility cannot provide CDT

The key is that you need a clear plan for escalation if you worsen, since the window for intervention narrows once hemodynamic collapse begins 3.