VV-ECMO without therapeutic blood thinners for severe respiratory failure

Anticoagulation-free VV ECMO for Acute Respiratory Failure: A Pilot Safety and Feasibility Randomized Clinical Trial

Phase2; Phase3 Interventional University Health Network, Toronto · NCT04273607

This pilot trial tries running veno-venous ECMO without therapeutic anticoagulants to see if it's safe for adults with ARDS.

Quick facts

PhasePhase2; Phase3
Study typeInterventional
Enrollment40 (estimated)
Ages18 Years and up
SexAll
SponsorUniversity Health Network, Toronto Academic / other
Locations1 site (Toronto, Ontario)
Trial IDNCT04273607 on ClinicalTrials.gov

What this trial studies

The study enrolls adult patients with ARDS supported on veno-venous ECMO and implements an anticoagulation-free management strategy using heparin-coated circuits and close monitoring. Participants meeting protocol criteria will generally receive only subcutaneous prophylactic heparin rather than continuous therapeutic unfractionated heparin. Outcomes include circuit thrombosis, thromboembolic events, major bleeding, need for circuit exchanges, and feasibility measures such as protocol adherence. The goal is to determine whether withholding therapeutic anticoagulation is safe and practicable in this population.

Who should consider this trial

Good fit: Ideal candidates are adults with ARDS on veno-venous ECMO who have no current indication for therapeutic anticoagulation and no contraindication to the protocol.

Not a fit: Patients who require therapeutic anticoagulation (for example for pulmonary embolism or DVT), have heparin-induced thrombocytopenia, active major bleeding, recent surgery precluding anticoagulation, low-flow ECCO2R, or who need veno-arterial support are unlikely to benefit.

Why it matters

Potential benefit: If successful, this approach could reduce bleeding complications and simplify ECMO management by avoiding full-dose anticoagulation.

How similar studies have performed: Small case series and observational reports suggest anticoagulation-free VV-ECMO can be feasible and safe in select patients, but randomized trials are lacking.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Adult patient with ARDS on VV-ECMO

Exclusion Criteria:

* Contraindication to anticoagulation with UFH (known heparin-induced thrombocytopenia, active hemorrhage, any surgery precluding the use of anticoagulation),
* Indication for therapeutic anticoagulation (pulmonary embolism or deep vein thrombosis, chronic anticoagulation therapy before ECMO insertion)
* Low-flow (\<2 liters/min) VV-ECMO (ECCO2R)

Where this trial is running

Toronto, Ontario

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Extracorporeal Membrane Oxygenation ComplicationExtracorporeal membrane oxygenationAnticoagulationThrombosisHemorrhage
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.