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CANARY in the Cath Lab? New RCT Catheter-based Lytics for Intermediate PE

December 16, 2022

Written by Seth Walsh-Blackmore

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This underpowered RCT did not find a statistically significant difference between catheter-directed thrombolysis (CDT) and anticoagulation monotherapy for intermediate-high risk pulmonary embolism (PE) in its primary outcome but favored CDT in secondary endpoints, without a difference in safety.

Why does this matter?
Identifying the subgroup of intermediate-high risk patients who may benefit from thrombolytic therapy, determining how the thrombolytic is given, and how much is given has been a dominant focus of acute PE research over the last decade. The largest trial to date of systemic thrombolysis in intermediate-high risk PE (PEITHO) reported a decreased the risk of deterioration relative to anticoagulation but an increased risk of serious bleeding and stroke. Could CDT yield the benefits without increasing harm?

CANARY in the cath lab?
This was an open-label RCT in adult patients diagnosed with acute intermediate-high risk PE by ESC criteria.  Patients were randomized to CDT + anticoagulation vs. anticoagulation monotherapy. Patients with high-risk (massive) PE and contraindications to thrombolytics were excluded. Outcome assessors were blinded.

The proportion of patients with RV dysfunction (RV/LV ratio >0.9) at 3 months was lower in the CDT group 2/46 (4.3%) when compared to the anticoagulation group 5/39 (12.8%), but this was not a statistically significant difference: OR 0.31 (95%CI 0.06-1.69). Fewer patients randomized to CDT experienced a 3-month composite of death or RV/LV > 0.9: OR 0.20 (95%CI 0.04-1.03; p=.048). There was no difference in the composite outcome of fatal bleeding, intracranial hemorrhage, and major bleeding between groups. 

This trial fell well short of its enrollment goals due to COVID-related stoppage The data are hypothesis generating and provide evidence of feasibility for intermediate-high-risk PE management. The HI-PEITHO trial is actively enrolling and seeks to address lingering questions regarding short-term and long-term outcomes in this population.

Peer reviewed by Bo Stubblefield

Catheter-Directed Thrombolysis vs Anticoagulation in Patients With Acute Intermediate-High-risk Pulmonary Embolism: The CANARY Randomized Clinical Trial. JAMA Cardiol. 2022 Oct 19:e223591. doi: 10.1001/jamacardio.2022.3591. Epub ahead of print.

Another Spoonful
Check out these two recent reviews in NEJM and JAMA on acute PE:

What are your thoughts?