Lung TransplantationLUX-ET-LTNCT06868823
Prospective Observational Pilot Study of LMWH Versus UFH as ECMO Anticoagulation in Lung Transplantation
An observational study of Lung Transplantation and Extracorporeal Membrane Oxygenation (ECMO), run by University Hospital, Motol at 1 site in Czechia.
Trial summary
The aim of this observational pilot study is to evaluate the effectiveness and safety of low-molecular-weight heparin (LMWH) compared to unfractionated heparin (UFH) as anticoagulation in perioperative ECMO during bilateral lung transplantation. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Lung Transplantation, Extracorporeal Membrane Oxygenation (ECMO), Anticoagulants and Bleeding Disorders
- Type of treatment
- Injection or infusion
- How many people
- 40 participants
- Where
- 1 siteCzechia
- Study dates
- 1 May 2025to 31 Dec 2025
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: The study population will consist of patients indicated for bilateral lung transplantation from the Czech Republic and Slovakia, who will undergo surgery at Motol Hospital in Prague.
Who may be able to join
- ⃣ Adults (≥18 years old).
- ⃣ Patients undergoing bilateral lung transplantation with perioperative veno-arterial (V-A) ECMO support.
- ⃣ Planned perioperative anticoagulation with either UFH or LMWH, as determined by the attending anesthesiologist.
- ⃣ Ability to provide informed consent or consent provided by a legally authorized representative.
Who cannot join
- ⃣ Patients receiving ECMO as a bridge to lung transplantation.
- ⃣ Patients requiring postoperative continuation of ECMO.
- ⃣ Patients with perioperative blood loss ≥3,000 mL.
- ⃣ Patients undergoing lung re-transplantation.
- ⃣ History of severe coagulopathy or bleeding disorder.
- ⃣ Active use of antiplatelet or anticoagulant therapy (excluding study anticoagulants).
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- ⃣ Known heparin-induced thrombocytopenia (HIT).
- ⃣ Severe liver dysfunction (Child-Pugh C) or end-stage renal disease requiring dialysis.
- ⃣ Pregnant or breastfeeding women.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Czechia1 site, 1 recruiting
- Recruiting
University Hospital Motol, 2nd Faculty of Medicine, Charles University in Prague and 3rd Department of Surgery, First Faculty of Medicine, Charles University, and Motol University Hospital, Lung Transplant Program
Prague, Czech Republic, 150 06
Miroslav Durila, prof. M.D., Ph.D., MHA, +420224435440, miroslav.durila@fnmotol.cz
Gabriela Holubova, M.D., +420224435440, gabriela.holubova@fnmotol.cz
About this study
Official title: LMWH Versus UFH as ECMO Anticoagulation in Lung Transplantation: A Prospective, Observational, and Pilot Study
The aim of this observational pilot study is to evaluate the effectiveness and safety of low-molecular-weight heparin (LMWH) compared to unfractionated heparin (UFH) as anticoagulation in perioperative ECMO during bilateral lung transplantation.
The main question this study seeks to answer is:
Read more
Does LMWH provide a safe and effective alternative to UFH for ECMO anticoagulation in lung transplantation, with reduced bleeding and thrombotic complications?
Patients undergoing bilateral lung transplantation with perioperative veno-arterial (V-A) ECMO support will be assigned to one of two anticoagulation strategies:
UFH group: Standard UFH anticoagulation monitored using ROTEM. LMWH group: Enoxaparin-based anticoagulation monitored using ROTEM. The study will assess perioperative blood loss, hemoglobin levels, transfusion needs, and thrombotic events. Additional analyses will include coagulation profile assessments using point-of-care (POC) tests, thrombin generation test (TGT), and laboratory coagulation parameters.
Read the detailed description
Introduction:
Extracorporeal circulation known as "extracorporeal membrane oxygenation" (ECMO) is a method of supportive therapy for terminal respiratory failure (1-3) or temporary replacement of lung function in the perioperative period during lung transplantation (4). In the former case, it is V-V ECMO (veno-venous ECMO), while in the latter case it is V-A ECMO (veno-arterial ECMO). According to the EURO-ELSO recommendations, the use of unfractionated heparin (UFH) is recommended as anticoagulation of the ECMO set (5). However, 40-50% of patients on ECMO experience not only bleeding but also thrombotic complications (6,7). Nowadays, there is an increasing number of case reports and small studies showing that UFH is not used and instead only standard thrombosis prophylaxis with low molecular weight heparin (LMWH) is administered without signs of thrombosis in the ECMO set (8,9). ECMO has been shown to cause impaired primary hemostasis, which can be detected by devices such as the PFA 200, ROTEM-Platelet, and Multiplate. The main pathology involves platelets and to a lesser extent von Willebrand factor (vWF) (10-12). The ECMO system is a high-flow "high shear stress" system that is comparable to the arterial circulation in vivo. In this setting, the so-called "white thrombus" plays a major role in thrombosis formation. Antiplatelet drugs are commonly used to prevent thrombosis in such a system, for example in cardiology and neurology. Thus, it can be assumed that ECMO-induced impairment of primary hemostasis, specifically impaired platelet plug formation, could naturally serve as a prevention of white thrombus formation and thrombosis of the ECMO set. However, prevention of thrombosis in the venous system or on the surface of ECMO cannulae, i.e., prevention of "red thrombus formation", is still necessary because of the existence of the Virchow triad. Since the main target of action of LMWH is factor FXa and the main target of UFH is mainly factor FIIa, it can be assumed that LMWH could be sufficient to prevent thrombosis, with minimal risk of bleeding. It is important to emphasize that LMWH only minimally blocks thrombin generation and affects the conversion of fibrinogen to fibrin only to a limited extent (i.e., thrombin time - TT), unlike UFH. Moreover, ROTEM testing can be used to monitor both UFH and LMWH (13-16). A recent study published by us supports this hypothesis and suggests that the use of LMWH in patients on ECMO support may represent a safe alternative to anticoagulation or thromboprophylaxis. The study shows that its use resulted in a relatively low incidence of bleeding and thrombotic complications (17). Thus, it can be assumed that LMWH will be suitable and effective for the prevention of thrombus formation with minimal risk of bleeding, even in patients undergoing lung transplantation with perioperative ECMO support. This hypothesis is supported by studies that have found that UFH leads to higher platelet activation compared with LMWH (18-20). On the other hand, the use of activated factor FVIIa at low doses of 12 µg/kg appears to be safe (without increasing thrombotic events) and effective in reducing postoperative bleeding in cardiac surgery. Since FVIIa acts at the site of damaged endothelium, it can be assumed that relatively small doses of FVIIa will be sufficient to stop bleeding, but not so high as to cause thrombosis. In addition, it can be assumed that isolated administration of this factor may be less thrombogenic compared with other preparations that also contain factors acting on the axes of the intrinsic clotting pathway, such as prothrombin complex concentrate (PCC, contains FII, FVII, FIX, FX) or Haemate P (contains vWF and FVIII). Therefore, early administration of low-dose FVIIa may represent an effective way to minimize perioperative blood loss without increasing the risk of thrombosis (21). Another property of recombinant activated FVIIa is its ability to positively affect platelet adhesion and aggregation, which is present during ECMO support (20,22).
Aim and nature of the study:
This is a pilot observational study to prospectively compare two groups of patients with different types of anticoagulation (LMWH vs. UFH) undergoing bilateral lung transplantation with perioperative V-A ECMO support.
Hypothesis:
The use of LMWH represents a safe alternative method of ECMO anticoagulation and thromboprophylaxis that reduces the rate of bleeding and thrombotic complications compared to the current method of anticoagulation with UFH.
Methodology:
The study was approved by the Ethics Committee of Motol University Hospital. All patients enrolled in the study will sign an informed consent for participation in the study and data collection. It will be explained to the patients that there are two types of anticoagulation that are currently standardly used at Motol Hospital for patients with ECMO support. The type of anticoagulation will be determined at the discretion of the anaesthesiologist, with the aim of dividing patients as evenly as possible into different groups. Two groups of patients with different types of anticoagulation (LMWH vs. UFH) will be compared. As this is a pilot project, a total of 40 patients will be included in the study, with each group comprising 20 patients.
In case of blood loss ≥ 500 ml and ongoing bleeding, i.e. "wet operating field", the following Motol University bleeding management protocol will be initiated in both UFH and LMWH group:
- investigate PFA 200 (Col/EPI) and ROTEM (EXTEM, INTEM, FIBTEM and HEPTEM)
- in case of pathology of PFA 200 and/or CT EXTEM/CT HEPTEM - administer Novoseven at 10-30 ug/kg (recombinant activated factor VIIa)
- re-examine all ROTEM tests (EXTEM, FIBTEM, HEPTEM) and if needed normalize them:
- CT-EXTEM > 80s by administering PCC at 10-30 ug/kg
- normalise CT-HEPTEM > 240s by administering Haemate P at 10-30j/kg
- for FIBTEM pathology - administer Exacyl at 10-30 mg/kg prior to Fibrinogen administration and normalize FIBTEM MCF ≤10 mm by administering Hemocompletan at 10-30 mg/kg - or more precisely: desired MCF - current MCF x 6.25 mg/kg e.g. (10 - 4) x (6.25 x 80 kg) = 3000 mg (add 0.5 g of fibrinogen per 1 mm)
- administer platelets at EXTEM MCF ≤ 50mm and FIBTEM MCF ≥ 10mm administer 5-10 mL/kg platelets (2 TU platelets from apheresis in an adult patient) or maintain platelets ≥ 50-100 x109/L
- if bleeding continues give Factor XIII - Fibrogammin at 10-30j/kg
- if PFA Col/EPI pathology persists and bleeding continues - give Haemate P at 20-40j/kg (if not already given to correct CT INTEM)
- if bleeding continues, repeat Novoseven 10-30 ug/kg every 4 hours for a total of 3 times
- if severe bleeding continues, give full dose of Novoseven 100 ug/kg
- if bleeding does not stop - discontinue anticoagulation/thromboprophylaxis
Note:
- for blood loss over 50% of blood volume, consider Octaplas or frozen plasma (in an adult patient with blood loss over 2000-3000 ml)
- maintain normal pH, calcium, magnesium, normothermia and haematocrit ≥0.3 (required for normal primary haemostasis)
- administer 5% albumin or transfusion products as above to maintain normovolemia (try to minimise intake of other colloids or crystalloids)
Statistical analysis:
statistical program GraphPad will be used, paired t-test, p < 0.05
- Conditions
- Lung Transplantation, Extracorporeal Membrane Oxygenation (ECMO), Anticoagulants and Bleeding Disorders
- Keywords
- Lung Transplantation, Extracorporeal Membrane Oxygenation (ECMO), Anticoagulation, Low-Molecular-Weight Heparin (LMWH), Unfractionated Heparin (UFH), Thrombosis Prevention, Bleeding Complications, Coagulation Management in Surgery, Hemorrhagic and Thrombotic Events, Perioperative Hemostasis
- Medical subject headings
- Hemostatic Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| UFH Anticoagulation Group | Participants in this group will receive unfractionated heparin (UFH) as the standard anticoagulation regimen during perioperative veno-arterial (V-A) ECMO support for bilateral lung transplantation. UFH Administration: A bolus of 20-40 IU/kg UFH will be administered 30 minutes before ECMO initiation. Continuous UFH infusion of 2-6 mL/h (dilution: 100 mg/50 mL) will be maintained. Coagulation Monitoring: ROTEM (EXTEM, INTEM, HEPTEM, FIBTEM) will be used for real-time assessment. The target CT INTEM/CT HEPTEM ratio will be maintained at 1.2-1.5 to guide anticoagulation adjustments. Coagulation and Hemostasis Assessments: Standard laboratory coagulation tests (aPTT, PT, TT, fibrinogen, FXIII, D-dimers, anti-Xa, platelet count, hemoglobin, hematocrit) will be performed at predefined timepoints. Point-of-care (POC) testing and thrombin generation test (TGT) will be used for additional evaluation. | |
| LMWH Anticoagulation Group | Participants in this group will receive low-molecular-weight heparin (LMWH) as an alternative anticoagulation strategy during perioperative veno-arterial (V-A) ECMO support for bilateral lung transplantation. LMWH Administration: A bolus of 20-40 IU/kg LMWH (Enoxaparin) will be administered 30 minutes before ECMO initiation. Continuous LMWH infusion of 2-6 mL/h (dilution: 100 mg/50 mL) will be maintained. Coagulation Monitoring: ROTEM (EXTEM, INTEM, HEPTEM, FIBTEM) will be used for real-time assessment. The CT INTEM/CT HEPTEM difference will be maintained at 20-30 seconds to guide anticoagulation adjustments. Coagulation and Hemostasis Assessments: Standard laboratory coagulation tests (aPTT, PT, TT, fibrinogen, FXIII, D-dimers, anti-Xa, platelet count, hemoglobin, hematocrit) will be performed at predefined timepoints. Point-of-care (POC) testing and thrombin generation test (TGT) will be used for additional evaluation. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Perioperative Blood Loss
Total volume of blood lost (milliliters, mL) during surgery, measured as the volume collected in suction canisters at the end of the operation, after subtracting irrigation fluids.
Measured: Measured intraoperatively, at the end of surgery.
Change in Hemoglobin Levels during surgery and within 24 hours after surgery
The difference in hemoglobin levels (g/L) measured at baseline (preoperative) and at the end of surgery and between immediate postoperative levels and after 24 hours after surgery. This outcome evaluates the extent of perioperative blood loss and its impact on oxygen-carrying capacity.
Measured: Intraoperative: Change in hemoglobin from preoperative levels to the end of surgery. Postoperative: Change in hemoglobin from preoperative levels to 24 hours post-surgery.
Blood Transfusion Requirements during surgery and Within 24 Hours after surgery
The total number of packed red blood cell (PRBC) units transfused to the patient intraoperatively and within the first 24 hours postoperatively. This outcome assesses the extent of blood loss and the need for transfusion support in ECMO-supported lung transplantation.
Measured: Intraoperative: PRBC transfusions administered during surgery. Postoperative: PRBC transfusions administered within the first 24 hours after surgery.
Incidence of Thrombotic Complications during surhery and within 24 Hours postoperatively.
The number of thrombotic events occurring intraoperatively and within the first 24 hours postoperatively, including ECMO circuit thrombosis, deep vein thrombosis (DVT), arterial thrombosis, pulmonary embolism (PE), myocardial infarction (MI), and ischemic stroke (CVA).
Thrombotic complications will be identified based on clinical signs, imaging studies, and laboratory results, including:
ECMO circuit thrombosis requiring urgent ECMO replacement. Limb ischemia due to arterial or venous thrombosis. Deep vein thrombosis (DVT) with >50% luminal obstruction, confirmed by ultrasound.
Pulmonary embolism (PE) confirmed by CT pulmonary angiography. Myocardial infarction (MI) diagnosed based on electrocardiographic changes and cardiac biomarkers.
Ischemic stroke (CVA) confirmed by neurological examination and brain imaging (CT/MRI).
Measured: Intraoperative: Thrombotic events occurring during surgery. Postoperative: Thrombotic events occurring within 24 hours after surgery.
Secondary outcomes (3)
Coagulation Profile Assessed by Point-of-Care (POC) Tests
Assessment of coagulation function using point-of-care (POC) testing, including ROTEM Sigma and PFA-200, to evaluate differences in hemostatic profiles between LMWH and UFH anticoagulation strategies during perioperative ECMO support in lung transplantation.
ROTEM Sigma: EXTEM, INTEM, FIBTEM, HEPTEM-parameters CT (seconds), CFT (seconds), MCF (mm), ML (%) PFA-200: Col/EPI test for platelet function assessment of CT in seconds
Measured: Before anticoagulation administration; 5 minutes after anticoagulation; at ≥500 mL blood loss with ongoing bleeding "wet surgical field"; 5 minutes after NovoSeven (activated FVIIa); at end of surgery before ECMO explantation; upon ICU admission
Coagulation Profile Assessed by Thrombin Generation Test (TGT)
Evaluation of coagulation potential and thrombin generation capacity using the Thrombin Generation Test (TGT) to compare the effects of LMWH vs. UFH on hemostatic function in ECMO-supported lung transplantation.
Key parameters measured:
Lag time (initiation of thrombin formation) in minutes. Peak thrombin concentration (maximum thrombin level) in nanomolar. Time to peak (speed of thrombin generation) in minutes. Endogenous thrombin potential (ETP) (total thrombin formed) in nanomolar minutes.
Measured: Before anticoagulation administration; 5 minutes after anticoagulation; at ≥500 mL blood loss with ongoing bleeding "wet surgical field"; 5 minutes after NovoSeven (activated FVIIa); at end of surgery before ECMO explantation; upon ICU admission
Coagulation Profile Assessed by Standard Laboratory Tests
Assessment of coagulation status using standard laboratory tests to evaluate differences in hemostatic profiles between LMWH and UFH anticoagulation strategies in ECMO-supported lung transplantation.
Blood samples will be analyzed for standard coagulation parameters, including:
Activated partial thromboplastin time (aPTT) in seconds. Prothrombin time (PT) in seconds. Thrombin time (TT) in seconds. Fibrinogen levels in g/L. Factor XIII (FXIII) levels in %. D-dimers in mg/L FEU. Fibrin monomers (FM) in mg/L. Antithrombin activity in %. Anti-Xa level in IU/mL. Platelet count x109/L Hemoglobin in g/L.
Measured: Before anticoagulation administration; 5 minutes after anticoagulation; at ≥500 mL blood loss with ongoing bleeding "wet surgical field"; 5 minutes after NovoSeven (activated FVIIa); at end of surgery before ECMO explantation; upon ICU admission
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Mar 2025
- Study start1 May 2025
- Primary completion31 Dec 2025 (estimated)
- Study completion31 Dec 2025 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (22)Papers the sponsor has linked to this study.
- Other trials for Lung TransplantationStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case-control
- Time perspective
- Prospective
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Hospital, Motol
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Durila Miroslav MUDr. Ph.D., University Hospital, Motol
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06868823
- Sponsor's protocol ID
- EK-704-24
- Acronym
- LUX-ET-LT
- Status last verified
- Jun 2025
- First submitted
- 21 Feb 2025
- Last updated
- 10 Jun 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Outcome measures (primary and secondary endpoints) Laboratory test results relevant to the study Adverse event data
Publications
Lisman T, Adelmeijer J, Heijnen HF, de Groot PG. Recombinant factor VIIa restores aggregation of alphaIIbbeta3-deficient platelets via tissue factor-independent fibrin generation. Blood. 2004 Mar 1;103(5):1720-7. doi: 10.1182/blood-2003-07-2287. Epub 2003 Oct 30.
PubMed 14592825Brase J, Finger B, He J, Wirtz K, Stun L, McMillen R, Flynn B. Analysis of Outcomes Using Low-Dose and Early Administration of Recombinant Activated Factor VII in Cardiac Surgery. Ann Thorac Surg. 2016 Jul;102(1):35-40. doi: 10.1016/j.athoracsur.2016.01.004. Epub 2016 Feb 10.
PubMed 26874365Xiao Z, Theroux P. Platelet activation with unfractionated heparin at therapeutic concentrations and comparisons with a low-molecular-weight heparin and with a direct thrombin inhibitor. Circulation. 1998 Jan 27;97(3):251-6. doi: 10.1161/01.cir.97.3.251.
PubMed 9462526Burgess JK, Chong BH. The platelet proaggregating and potentiating effects of unfractionated heparin, low molecular weight heparin and heparinoid in intensive care patients and healthy controls. Eur J Haematol. 1997 Apr;58(4):279-85. doi: 10.1111/j.1600-0609.1997.tb01667.x.
PubMed 9186540Ajayi AA, Pharmacols FB, Cooper J, Horn EH, Rubin PC. Comparison of the effects of unfractionated heparin and the low-molecular-weight heparins dalteparin and enoxaparin on spontaneous platelet aggregation and adenosine diphosphate activity in platelets during the third trimester of pregnancy. Methods Find Exp Clin Pharmacol. 2007 Oct;29(8):539-45. doi: 10.1358/mf.2007.29.8.1116308.
PubMed 18040530Durila M, Vajter J, Garaj M, Berousek J, Lischke R, Hlavacek M, Vymazal T. Intravenous enoxaparin guided by anti-Xa in venovenous extracorporeal membrane oxygenation: A retrospective, single-center study. Artif Organs. 2025 Mar;49(3):486-496. doi: 10.1111/aor.14879. Epub 2024 Oct 3.
PubMed 39360891Yassen KA, Refaat EK, Helal SM, Metwally AA, Youssef SD, Gorlinger K. Detection and quantification of perioperative heparin-like effects by rotational thromboelastometry in living-donor liver transplant recipients: A prospective observational study. J Anaesthesiol Clin Pharmacol. 2023 Apr-Jun;39(2):285-291. doi: 10.4103/joacp.joacp_521_21. Epub 2022 Jun 15.
PubMed 37564856Rigal JC, Boissier E, Lakhal K, Riche VP, Durand-Zaleski I, Rozec B. Cost-effectiveness of point-of-care viscoelastic haemostatic assays in the management of bleeding during cardiac surgery: protocol for a prospective multicentre pragmatic study with stepped-wedge cluster randomised controlled design and 1-year follow-up (the IMOTEC study). BMJ Open. 2019 Nov 5;9(11):e029751. doi: 10.1136/bmjopen-2019-029751.
PubMed 31694845Schaden E, Schober A, Hacker S, Spiss C, Chiari A, Kozek-Langenecker S. Determination of enoxaparin with rotational thrombelastometry using the prothrombinase-induced clotting time reagent. Blood Coagul Fibrinolysis. 2010 Apr;21(3):256-61. doi: 10.1097/MBC.0b013e328337014c.
PubMed 20087172Ichikawa J, Kodaka M, Nishiyama K, Hirasaki Y, Ozaki M, Komori M. Reappearance of circulating heparin in whole blood heparin concentration-based management does not correlate with postoperative bleeding after cardiac surgery. J Cardiothorac Vasc Anesth. 2014 Aug;28(4):1003-7. doi: 10.1053/j.jvca.2013.10.010. Epub 2014 Feb 5.
PubMed 24508375Durila M, Vajter J, Garaj M, Smetak T, Hedvicak P, Berousek J, Vymazal T. Acquired primary hemostasis pathology detected by platelet function analyzer 200 seen during extracorporeal membrane oxygenation is sufficient to prevent circuit thrombosis: A pilot study. J Heart Lung Transplant. 2020 Sep;39(9):980-982. doi: 10.1016/j.healun.2020.05.015. Epub 2020 Jun 11. No abstract available.
PubMed 32591313Garaj M, Durila M, Vajter J, Solcova M, Marecek F, Hrachovinova I. Extracorporeal membrane oxygenation seems to induce impairment of primary hemostasis pathology as measured by a Multiplate analyzer: An observational retrospective study. Artif Organs. 2022 May;46(5):899-907. doi: 10.1111/aor.14142. Epub 2021 Dec 17.
PubMed 34904233Garaj M, Francesconi A, Durila M, Vajter J, Holubova G, Hrachovinova I. ECMO produces very rapid changes in primary hemostasis detected by PFA-200 during lung transplantation: An observational study. J Heart Lung Transplant. 2024 Nov;43(11):1771-1776. doi: 10.1016/j.healun.2024.07.012. Epub 2024 Jul 20.
PubMed 39038564Gratz J, Pausch A, Schaden E, Baierl A, Jaksch P, Erhart F, Hoetzenecker K, Wiegele M. Low molecular weight heparin versus unfractioned heparin for anticoagulation during perioperative extracorporeal membrane oxygenation: A single center experience in 102 lung transplant patients. Artif Organs. 2020 Jun;44(6):638-646. doi: 10.1111/aor.13642. Epub 2020 Feb 18.
PubMed 31951030Lee YY, Baik HJ, Lee H, Kim CH, Chung RK, Han JI, Joo H, Woo JH. Heparin-free veno-venous extracorporeal membrane oxygenation in a multiple trauma patient: A case report. Medicine (Baltimore). 2020 Jan;99(5):e19070. doi: 10.1097/MD.0000000000019070.
PubMed 32000456
Study at a glance
From the registry record, last updated by the sponsor on 10 Jun 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- LMWH Versus UFH as ECMO Anticoagulation in Lung Transplantation: A Prospective, Observational, and Pilot Study
- ClinicalTrials.gov ID
- NCT06868823
- Acronym / sponsor ID
- LUX-ET-LT / EK-704-24
- Conditions
- Lung Transplantation, Extracorporeal Membrane Oxygenation (ECMO), Anticoagulants and Bleeding Disorders
- Keywords
- Lung Transplantation, Extracorporeal Membrane Oxygenation (ECMO), Anticoagulation, Low-Molecular-Weight Heparin (LMWH), Unfractionated Heparin (UFH), Thrombosis Prevention, Bleeding Complications, Coagulation Management in Surgery
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 40 participants (estimated)
- Lead sponsor
- University Hospital, MotolUniversity, hospital or other
- Study start
- 1 May 2025 (actual)
- Primary completion
- 31 Dec 2025 (estimated)
- Study completion
- 31 Dec 2025 (estimated)
- First posted
- 11 Mar 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The aim of this observational pilot study is to evaluate the effectiveness and safety of low-molecular-weight heparin (LMWH) compared to unfractionated heparin (UFH) as anticoagulation in perioperative ECMO during bilateral lung transplantation.
The main question this study seeks to answer is:
Does LMWH provide a safe and effective alternative to UFH for ECMO anticoagulation in lung transplantation, with reduced bleeding and thrombotic complications?
Patients undergoing bilateral lung transplantation with perioperative veno-arterial (V-A) ECMO support will be assigned to one of two anticoagulation strategies:
UFH group: Standard UFH anticoagulation monitored using ROTEM. LMWH group: Enoxaparin-based anticoagulation monitored using ROTEM. The study will assess perioperative blood loss, hemoglobin levels, transfusion needs, and thrombotic events. Additional analyses will include coagulation profile assessments using point-of-care (POC) tests, thrombin generation test (TGT), and laboratory coagulation parameters.
Detailed description
Introduction:
Extracorporeal circulation known as "extracorporeal membrane oxygenation" (ECMO) is a method of supportive therapy for terminal respiratory failure (1-3) or temporary replacement of lung function in the perioperative period during lung transplantation (4). In the former case, it is V-V ECMO (veno-venous ECMO), while in the latter case it is V-A ECMO (veno-arterial ECMO). According to the EURO-ELSO recommendations, the use of unfractionated heparin (UFH) is recommended as anticoagulation of the ECMO set (5). However, 40-50% of patients on ECMO experience not only bleeding but also thrombotic complications (6,7). Nowadays, there is an increasing number of case reports and small studies showing that UFH is not used and instead only standard thrombosis prophylaxis with low molecular weight heparin (LMWH) is administered without signs of thrombosis in the ECMO set (8,9). ECMO has been shown to cause impaired primary hemostasis, which can be detected by devices such as the PFA 200, ROTEM-Platelet, and Multiplate. The main pathology involves platelets and to a lesser extent von Willebrand factor (vWF) (10-12). The ECMO system is a high-flow "high shear stress" system that is comparable to the arterial circulation in vivo. In this setting, the so-called "white thrombus" plays a major role in thrombosis formation. Antiplatelet drugs are commonly used to prevent thrombosis in such a system, for example in cardiology and neurology. Thus, it can be assumed that ECMO-induced impairment of primary hemostasis, specifically impaired platelet plug formation, could naturally serve as a prevention of white thrombus formation and thrombosis of the ECMO set. However, prevention of thrombosis in the venous system or on the surface of ECMO cannulae, i.e., prevention of "red thrombus formation", is still necessary because of the existence of the Virchow triad. Since the main target of action of LMWH is factor FXa and the main target of UFH is mainly factor FIIa, it can be assumed that LMWH could be sufficient to prevent thrombosis, with minimal risk of bleeding. It is important to emphasize that LMWH only minimally blocks thrombin generation and affects the conversion of fibrinogen to fibrin only to a limited extent (i.e., thrombin time - TT), unlike UFH. Moreover, ROTEM testing can be used to monitor both UFH and LMWH (13-16). A recent study published by us supports this hypothesis and suggests that the use of LMWH in patients on ECMO support may represent a safe alternative to anticoagulation or thromboprophylaxis. The study shows that its use resulted in a relatively low incidence of bleeding and thrombotic complications (17). Thus, it can be assumed that LMWH will be suitable and effective for the prevention of thrombus formation with minimal risk of bleeding, even in patients undergoing lung transplantation with perioperative ECMO support. This hypothesis is supported by studies that have found that UFH leads to higher platelet activation compared with LMWH (18-20). On the other hand, the use of activated factor FVIIa at low doses of 12 µg/kg appears to be safe (without increasing thrombotic events) and effective in reducing postoperative bleeding in cardiac surgery. Since FVIIa acts at the site of damaged endothelium, it can be assumed that relatively small doses of FVIIa will be sufficient to stop bleeding, but not so high as to cause thrombosis. In addition, it can be assumed that isolated administration of this factor may be less thrombogenic compared with other preparations that also contain factors acting on the axes of the intrinsic clotting pathway, such as prothrombin complex concentrate (PCC, contains FII, FVII, FIX, FX) or Haemate P (contains vWF and FVIII). Therefore, early administration of low-dose FVIIa may represent an effective way to minimize perioperative blood loss without increasing the risk of thrombosis (21). Another property of recombinant activated FVIIa is its ability to positively affect platelet adhesion and aggregation, which is present during ECMO support (20,22).
Aim and nature of the study:
This is a pilot observational study to prospectively compare two groups of patients with different types of anticoagulation (LMWH vs. UFH) undergoing bilateral lung transplantation with perioperative V-A ECMO support.
Hypothesis:
The use of LMWH represents a safe alternative method of ECMO anticoagulation and thromboprophylaxis that reduces the rate of bleeding and thrombotic complications compared to the current method of anticoagulation with UFH.
Methodology:
The study was approved by the Ethics Committee of Motol University Hospital. All patients enrolled in the study will sign an informed consent for participation in the study and data collection. It will be explained to the patients that there are two types of anticoagulation that are currently standardly used at Motol Hospital for patients with ECMO support. The type of anticoagulation will be determined at the discretion of the anaesthesiologist, with the aim of dividing patients as evenly as possible into different groups. Two groups of patients with different types of anticoagulation (LMWH vs. UFH) will be compared. As this is a pilot project, a total of 40 patients will be included in the study, with each group comprising 20 patients.
In case of blood loss ≥ 500 ml and ongoing bleeding, i.e. "wet operating field", the following Motol University bleeding management protocol will be initiated in both UFH and LMWH group:
- investigate PFA 200 (Col/EPI) and ROTEM (EXTEM, INTEM, FIBTEM and HEPTEM)
- in case of pathology of PFA 200 and/or CT EXTEM/CT HEPTEM - administer Novoseven at 10-30 ug/kg (recombinant activated factor VIIa)
- re-examine all ROTEM tests (EXTEM, FIBTEM, HEPTEM) and if needed normalize them:
- CT-EXTEM > 80s by administering PCC at 10-30 ug/kg
- normalise CT-HEPTEM > 240s by administering Haemate P at 10-30j/kg
- for FIBTEM pathology - administer Exacyl at 10-30 mg/kg prior to Fibrinogen administration and normalize FIBTEM MCF ≤10 mm by administering Hemocompletan at 10-30 mg/kg - or more precisely: desired MCF - current MCF x 6.25 mg/kg e.g. (10 - 4) x (6.25 x 80 kg) = 3000 mg (add 0.5 g of fibrinogen per 1 mm)
- administer platelets at EXTEM MCF ≤ 50mm and FIBTEM MCF ≥ 10mm administer 5-10 mL/kg platelets (2 TU platelets from apheresis in an adult patient) or maintain platelets ≥ 50-100 x109/L
- if bleeding continues give Factor XIII - Fibrogammin at 10-30j/kg
- if PFA Col/EPI pathology persists and bleeding continues - give Haemate P at 20-40j/kg (if not already given to correct CT INTEM)
- if bleeding continues, repeat Novoseven 10-30 ug/kg every 4 hours for a total of 3 times
- if severe bleeding continues, give full dose of Novoseven 100 ug/kg
- if bleeding does not stop - discontinue anticoagulation/thromboprophylaxis
Note:
- for blood loss over 50% of blood volume, consider Octaplas or frozen plasma (in an adult patient with blood loss over 2000-3000 ml)
- maintain normal pH, calcium, magnesium, normothermia and haematocrit ≥0.3 (required for normal primary haemostasis)
- administer 5% albumin or transfusion products as above to maintain normovolemia (try to minimise intake of other colloids or crystalloids)
Statistical analysis:
statistical program GraphPad will be used, paired t-test, p < 0.05
Study design
- Observational model
- Case-control
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| UFH Anticoagulation Group | – | –Participants in this group will receive unfractionated heparin (UFH) as the standard anticoagulation regimen during perioperative veno-arterial (V-A) ECMO support for bilateral lung transplantation. UFH Administration: A bolus of 20-40 IU/kg UFH will be administered 30 minutes before ECMO initiation. Continuous UFH infusion of 2-6 mL/h (dilution: 100 mg/50 mL) will be maintained. Coagulation Monitoring: ROTEM (EXTEM, INTEM, HEPTEM, FIBTEM) will be used for real-time assessment. The target CT INTEM/CT HEPTEM ratio will be maintained at 1.2-1.5 to guide anticoagulation adjustments. Coagulation and Hemostasis Assessments: Standard laboratory coagulation tests (aPTT, PT, TT, fibrinogen, FXIII, D-dimers, anti-Xa, platelet count, hemoglobin, hematocrit) will be performed at predefined timepoints. Point-of-care (POC) testing and thrombin generation test (TGT) will be used for additional evaluation. |
| LMWH Anticoagulation Group | – | –Participants in this group will receive low-molecular-weight heparin (LMWH) as an alternative anticoagulation strategy during perioperative veno-arterial (V-A) ECMO support for bilateral lung transplantation. LMWH Administration: A bolus of 20-40 IU/kg LMWH (Enoxaparin) will be administered 30 minutes before ECMO initiation. Continuous LMWH infusion of 2-6 mL/h (dilution: 100 mg/50 mL) will be maintained. Coagulation Monitoring: ROTEM (EXTEM, INTEM, HEPTEM, FIBTEM) will be used for real-time assessment. The CT INTEM/CT HEPTEM difference will be maintained at 20-30 seconds to guide anticoagulation adjustments. Coagulation and Hemostasis Assessments: Standard laboratory coagulation tests (aPTT, PT, TT, fibrinogen, FXIII, D-dimers, anti-Xa, platelet count, hemoglobin, hematocrit) will be performed at predefined timepoints. Point-of-care (POC) testing and thrombin generation test (TGT) will be used for additional evaluation. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- The study population will consist of patients indicated for bilateral lung transplantation from the Czech Republic and Slovakia, who will undergo surgery at Motol Hospital in Prague.
Key inclusion criteria (4 listed)
- ⃣ Adults (≥18 years old).
- ⃣ Patients undergoing bilateral lung transplantation with perioperative veno-arterial (V-A) ECMO support.
- ⃣ Planned perioperative anticoagulation with either UFH or LMWH, as determined by the attending anesthesiologist.
- ⃣ Ability to provide informed consent or consent provided by a legally authorized representative.
Key exclusion criteria (9 listed)
- ⃣ Patients receiving ECMO as a bridge to lung transplantation.
- ⃣ Patients requiring postoperative continuation of ECMO.
- ⃣ Patients with perioperative blood loss ≥3,000 mL.
- ⃣ Patients undergoing lung re-transplantation.
- ⃣ History of severe coagulopathy or bleeding disorder.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Perioperative Blood Loss
Time frame: Measured intraoperatively, at the end of surgery.
Total volume of blood lost (milliliters, mL) during surgery, measured as the volume collected in suction canisters at the end of the operation, after subtracting irrigation fluids.
Change in Hemoglobin Levels during surgery and within 24 hours after surgery
Time frame: Intraoperative: Change in hemoglobin from preoperative levels to the end of surgery. Postoperative: Change in hemoglobin from preoperative levels to 24 hours post-surgery.
The difference in hemoglobin levels (g/L) measured at baseline (preoperative) and at the end of surgery and between immediate postoperative levels and after 24 hours after surgery. This outcome evaluates the extent of perioperative blood loss and its impact on oxygen-carrying capacity.
Blood Transfusion Requirements during surgery and Within 24 Hours after surgery
Time frame: Intraoperative: PRBC transfusions administered during surgery. Postoperative: PRBC transfusions administered within the first 24 hours after surgery.
The total number of packed red blood cell (PRBC) units transfused to the patient intraoperatively and within the first 24 hours postoperatively. This outcome assesses the extent of blood loss and the need for transfusion support in ECMO-supported lung transplantation.
Incidence of Thrombotic Complications during surhery and within 24 Hours postoperatively.
Time frame: Intraoperative: Thrombotic events occurring during surgery. Postoperative: Thrombotic events occurring within 24 hours after surgery.
The number of thrombotic events occurring intraoperatively and within the first 24 hours postoperatively, including ECMO circuit thrombosis, deep vein thrombosis (DVT), arterial thrombosis, pulmonary embolism (PE), myocardial infarction (MI), and ischemic stroke (CVA). Thrombotic complications will be identified based on clinical signs, imaging studies, and laboratory results, including: ECMO circuit thrombosis requiring urgent ECMO replacement. Limb ischemia due to arterial or venous thrombosis. Deep vein thrombosis (DVT) with >50% luminal obstruction, confirmed by ultrasound. Pulmonary embolism (PE) confirmed by CT pulmonary angiography. Myocardial infarction (MI) diagnosed based on electrocardiographic changes and cardiac biomarkers. Ischemic stroke (CVA) confirmed by neurological examination and brain imaging (CT/MRI).
3 secondary outcomes
Coagulation Profile Assessed by Point-of-Care (POC) Tests
Time frame: Before anticoagulation administration; 5 minutes after anticoagulation; at ≥500 mL blood loss with ongoing bleeding "wet surgical field"; 5 minutes after NovoSeven (activated FVIIa); at end of surgery before ECMO explantation; upon ICU admission
Coagulation Profile Assessed by Thrombin Generation Test (TGT)
Time frame: Before anticoagulation administration; 5 minutes after anticoagulation; at ≥500 mL blood loss with ongoing bleeding "wet surgical field"; 5 minutes after NovoSeven (activated FVIIa); at end of surgery before ECMO explantation; upon ICU admission
Coagulation Profile Assessed by Standard Laboratory Tests
Time frame: Before anticoagulation administration; 5 minutes after anticoagulation; at ≥500 mL blood loss with ongoing bleeding "wet surgical field"; 5 minutes after NovoSeven (activated FVIIa); at end of surgery before ECMO explantation; upon ICU admission
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Jun 2025.
- Background: PubMed 14592825Lisman T, Adelmeijer J, Heijnen HF, de Groot PG. Recombinant factor VIIa restores aggregation of alphaIIbbeta3-deficient platelets via tissue factor-independent fibrin generation. Blood. 2004 Mar 1;103(5):1720-7. doi: 10.1182/blood-2003-07-2287. Epub 2003 Oct 30.
- Background: PubMed 26874365Brase J, Finger B, He J, Wirtz K, Stun L, McMillen R, Flynn B. Analysis of Outcomes Using Low-Dose and Early Administration of Recombinant Activated Factor VII in Cardiac Surgery. Ann Thorac Surg. 2016 Jul;102(1):35-40. doi: 10.1016/j.athoracsur.2016.01.004. Epub 2016 Feb 10.
- Background: PubMed 9462526Xiao Z, Theroux P. Platelet activation with unfractionated heparin at therapeutic concentrations and comparisons with a low-molecular-weight heparin and with a direct thrombin inhibitor. Circulation. 1998 Jan 27;97(3):251-6. doi: 10.1161/01.cir.97.3.251.
- Background: PubMed 9186540Burgess JK, Chong BH. The platelet proaggregating and potentiating effects of unfractionated heparin, low molecular weight heparin and heparinoid in intensive care patients and healthy controls. Eur J Haematol. 1997 Apr;58(4):279-85. doi: 10.1111/j.1600-0609.1997.tb01667.x.
- Background: PubMed 18040530Ajayi AA, Pharmacols FB, Cooper J, Horn EH, Rubin PC. Comparison of the effects of unfractionated heparin and the low-molecular-weight heparins dalteparin and enoxaparin on spontaneous platelet aggregation and adenosine diphosphate activity in platelets during the third trimester of pregnancy. Methods Find Exp Clin Pharmacol. 2007 Oct;29(8):539-45. doi: 10.1358/mf.2007.29.8.1116308.
- Background: PubMed 39360891Durila M, Vajter J, Garaj M, Berousek J, Lischke R, Hlavacek M, Vymazal T. Intravenous enoxaparin guided by anti-Xa in venovenous extracorporeal membrane oxygenation: A retrospective, single-center study. Artif Organs. 2025 Mar;49(3):486-496. doi: 10.1111/aor.14879. Epub 2024 Oct 3.
- Background: PubMed 37564856Yassen KA, Refaat EK, Helal SM, Metwally AA, Youssef SD, Gorlinger K. Detection and quantification of perioperative heparin-like effects by rotational thromboelastometry in living-donor liver transplant recipients: A prospective observational study. J Anaesthesiol Clin Pharmacol. 2023 Apr-Jun;39(2):285-291. doi: 10.4103/joacp.joacp_521_21. Epub 2022 Jun 15.
- Background: PubMed 31694845Rigal JC, Boissier E, Lakhal K, Riche VP, Durand-Zaleski I, Rozec B. Cost-effectiveness of point-of-care viscoelastic haemostatic assays in the management of bleeding during cardiac surgery: protocol for a prospective multicentre pragmatic study with stepped-wedge cluster randomised controlled design and 1-year follow-up (the IMOTEC study). BMJ Open. 2019 Nov 5;9(11):e029751. doi: 10.1136/bmjopen-2019-029751.
- Background: PubMed 20087172Schaden E, Schober A, Hacker S, Spiss C, Chiari A, Kozek-Langenecker S. Determination of enoxaparin with rotational thrombelastometry using the prothrombinase-induced clotting time reagent. Blood Coagul Fibrinolysis. 2010 Apr;21(3):256-61. doi: 10.1097/MBC.0b013e328337014c.
- Background: PubMed 24508375Ichikawa J, Kodaka M, Nishiyama K, Hirasaki Y, Ozaki M, Komori M. Reappearance of circulating heparin in whole blood heparin concentration-based management does not correlate with postoperative bleeding after cardiac surgery. J Cardiothorac Vasc Anesth. 2014 Aug;28(4):1003-7. doi: 10.1053/j.jvca.2013.10.010. Epub 2014 Feb 5.
- Background: PubMed 32591313Durila M, Vajter J, Garaj M, Smetak T, Hedvicak P, Berousek J, Vymazal T. Acquired primary hemostasis pathology detected by platelet function analyzer 200 seen during extracorporeal membrane oxygenation is sufficient to prevent circuit thrombosis: A pilot study. J Heart Lung Transplant. 2020 Sep;39(9):980-982. doi: 10.1016/j.healun.2020.05.015. Epub 2020 Jun 11. No abstract available.
- Background: PubMed 34904233Garaj M, Durila M, Vajter J, Solcova M, Marecek F, Hrachovinova I. Extracorporeal membrane oxygenation seems to induce impairment of primary hemostasis pathology as measured by a Multiplate analyzer: An observational retrospective study. Artif Organs. 2022 May;46(5):899-907. doi: 10.1111/aor.14142. Epub 2021 Dec 17.
- Individual participant dataSharing planned: Yes. Outcome measures (primary and secondary endpoints) Laboratory test results relevant to the study Adverse event data
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Lung Transplantation and Extracorporeal Membrane Oxygenation (ECMO), run by University Hospital, Motol at 1 site in Czechia.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 10 Jun 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Czechia. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Miroslav Durila, prof. M.D., Ph.D., MHA (+420224435440, miroslav.durila@fnmoto.cz), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Perioperative Blood Loss (time frame: Measured intraoperatively, at the end of surgery.). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06868823, which also lists 22 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 10 Jun 2025.