ClinicalTrials.gg
RecruitingNCT03636295LIMITUpdated Sep 17, 2026

Low INR to Minimize Bleeding With Mechanical Valves Trial

A Phase 3 interventional study of Warfarin in Bleeding Post-mechanical Valve Replacement and Thromboembolism Post-mechanical Valve Replacement, sponsored by Population Health Research Institute. Recruiting at 45 sites in 18 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-17.

Sponsored by Population Health Research Institute · Phase 3, Interventional, and Treatment

From the registry’s dates

  • Started Sep 2019; still recruiting 7 years 2 months later.
Phase
Phase 3
Study type
Interventional
Enrollment
2,625
Allocation
Randomized
Ages
18 Years and older
Sex
All
01

Study summary

This study evaluates the use of a lower INR target (1.5 to 2.5) in patients with a mechanical bileaflet heart valve in the aortic position. This study will inform physicians about whether a lower INR target will decrease the risk of bleeding or increase the risk of blood clot formation and stroke. These results have the potential to reduce the burden of bleeding in patients with a mechanical heart valve who require lifelong warfarin (Coumadin) treatment.

Read the detailed description

Warfarin (Coumadin) is a blood thinner used to prevent blood clot formation in patients with mechanical heart valves. Blood clots can block blood flow to the brain, heart, or other parts of the body. Mechanical heart valves increases the risk of clot so patients with a mechanical heart valve must take warfarin to reduce their risk of stroke and other blood clot-related problems.

The degree to which warfarin 'works' varies from person to person, and so dosage is determined by measuring each person's response to the drug as an 'international normalized ratio' or INR. A patient with an INR over 1.0 has blood that takes longer to clot than average, and increasing INR values represent increasing time required for blood to clot. While an INR over 1.0 decreases clotting risk, it also increases bleeding risk. It is important to carefully balance these risks.

Specific INR targets have been recommended for patients with a mechanical heart valve, but these recommendations differ between scientific groups and are based on low quality evidence. Recent studies suggest that a lower INR target range than is currently recommended can be used safely. A laboratory study showed that warfarin effectively prevents blood clot formation on mechanical heart valves as long as the INR is 1.5 or above. Two moderately-sized clinical studies showed that an INR target range of 1.5-2.5 resulted in less bleeding than the usual higher target range without increasing blood clot formation or stroke in patients with a newer valve model. Whether we could use a lower INR target range for patients with a mechanical aortic valve remains controversial.

This study evaluates the use of a lower INR target (1.5 to 2.5) in patients with a mechanical bileaflet heart valve in the aortic position. This study will inform physicians about whether a lower INR target will decrease the risk of bleeding or increase the risk of blood clot formation and stroke. These results have the potential to reduce the burden of bleeding in patients with a mechanical heart valve who require lifelong warfarin (Coumadin) treatment.

02

Conditions studied

  • Bleeding Post-mechanical Valve Replacement
  • Thromboembolism Post-mechanical Valve Replacement

Keywords

  • Mechanical valve replacement
  • Vitamin K antagonist
  • INR targets
  • Bleeding
  • Thromboembolism
03

In context

Hemorrhage

1,383 studies on the registry are indexed under Hemorrhage; 244 are open to participants now.

This study's planned enrollment of 2,625 is above the median of 102 across 926 interventional studies indexed under Hemorrhage.

Browse Hemorrhage studies →

Lead sponsor

Population Health Research Institute is the lead sponsor of 115 studies on the registry; 26 are open to participants now.

Of its 5 completed or terminated interventional studies of FDA-regulated products, 1 (20%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Age is 18 or older at the time of enrolment
  • Have had a bileaflet mechanical heart valve implant in the aortic position 3 or more months ago
  • Written from either the patient or substitute decision maker

Exclusion criteria

Exclusion criteria:

  • Has a second implanted mechanical valve (any position)
  • Lower boundary of planned range is less than 2.0
  • Pregnant or expecting to become pregnant during the study follow-up
Terms in these criteria, in plain language(2)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

INR, PT and aPTT (clotting tests)

Blood tests of how long blood takes to clot. The INR is the prothrombin time (PT) put on a common scale; about 1 is usual for someone not taking a blood thinner.

Criteria often make an exception for people on a blood thinner such as warfarin, whose INR is raised on purpose.

05

Study design

Phase
Phase 3
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
None (open label)
Enrollment
2,625 participants (estimated)

Study arms

  • Experimental
    Reduced INR Target

    Warfarin therapy will be titrated to a target INR in the range of 1.5 to 2.5.

    Drug: Warfarin

  • Active comparator
    Standard INR Target

    Warfarin therapy will be titrated to a "standard of care" target INR range.

    Drug: Warfarin

Interventions

  • Participants in both arms will be on warfarin therapy post-mechanical valve replacement as is standard, but will have different INR target ranges.

    Also known as: Coumadin

06

What researchers measure

Primary outcomes

  1. Thrombosis/thromboembolism

    Number of patients who have at least one of the following: ischemic stroke, systemic thromboembolism, and valve thrombosis

    Time frame: Through study completion, an expected mean of 2-3 years

  2. Major bleeding

    Number of patients that have bleeding that results in the following: 1. Death and/or, 2. Symptomatic bleeding in critical area or organ (e.g. intracranial, intraspinal, intraocular, retroperitoneal, intraarticular, pericardial, in a non-operated joint, or intramuscular with compartment syndrome) and/or, 3. Bleeding that causes drop of hemoglobin level by 20 g/L or more, or that requires the transfusion of 2 or more units of packed red blood cells or whole blood

    Time frame: Through study completion, an expected mean of 2-3 years

Secondary outcomes

  1. All cause mortality

    Selected rather than cardiovascular mortality, as cause-specific mortality is often difficult to ascertain or define in complex cardiovascular patients in whom multi-end-organ dysfunction may accompany cardiovascular decline.

    Time frame: Through study completion, an expected mean of 2-3 years

  2. All clinically important bleeding

    Number of patients that experience all clinically important bleeding (major and minor)

    Time frame: Through study completion, an expected mean of 2-3 years

  3. Minor bleeding

    Number of patients that experience a bleed that does not meet major bleeding criteria

    Time frame: Through study completion, an expected mean of 2-3 years

  4. All stroke

    Number of patients that experience a strokes, including ischemic stroke, ischemic with secondary transformation, stroke of uncertain classification and hemorrhagic stroke

    Time frame: Through study completion, an expected mean of 2-3 years

  5. Ischemic stroke

    Number of patients that experience an ischemic stroke, defined as focal brain infarction caused by an arterial (or rarely venous) obstruction and as documented by CT/MRI that is normal or shows an infarct in the clinicall expected area

    Time frame: Through study completion, an expected mean of 2-3 years

  6. Hemorrhagic stroke

    Number of patients that experience a hemorrhagic stroke, defined as requiring neuroimaging or autopsy confirmation, and includes two subcategories: primary intracerebral hemorrhage and primary subarachnoid hemorrhage

    Time frame: Through study completion, an expected mean of 2-3 years

  7. Type 1, 2 or 3 myocardial infarction

    Number of patients who experience a type 1, 2 or 3 myocardial infarction

    Time frame: Through study completion, an expected mean of 2-3 years

  8. Systemic thromboembolism

    Number of patients who experience a systemic thromboembolism

    Time frame: Through study completion, an expected mean of 2-3 years

  9. Valve thrombosis

    Number of patients who experience a valve thrombosis

    Time frame: Through study completion, an expected mean of 2-3 years

  10. Pulmonary embolism

    Number of patients who experience a pulmonary embolism

    Time frame: Through study completion, an expected mean of 2-3 years

  11. Deep vein thrombosis

    Number of patients who experience a deep vein thrombosis

    Time frame: Through study completion, an expected mean of 2-3 years

  12. New renal replacement therapy

    Number of patients requiring new renal replacement therapy

    Time frame: Through study completion, an expected mean of 2-3 years

  13. Time in therapeutic range

    The percentage of time the patient's INR was within the target range

    Time frame: Through study completion, an expected mean of 2-3 years

  14. Proportion of patients with extreme INR values (>4)

    The proportion of patients with at least one reported INR value above 4

    Time frame: Through study completion, an expected mean of 2-3 years

07

Study locations

45 of 45 sites recruiting
  • Ziekenhuis Oost-Limburg
    Genk, Limburg 3600, Belgium
    Recruiting
    • Philippe Bertrand, MD · Contact
    • Philippe Bertrand, MD · Principal investigator
  • AZ Oostende
    Ostend, West-Vlaanderen 8400, Belgium
    Recruiting
    • Johannes Heymeriks, MD · Principal investigator
  • Imelda Hospital
    Keerbergen, 2820, Belgium
    Recruiting
    • Herbert De Praetere, MD · Principal investigator
  • Universitair Ziekenhuis Leuven
    Leuven, 3000, Belgium
    Recruiting
    • Filip Rega, MD · Principal investigator
  • University of Botswana, at Princess Marina Hospital
    Gaborone, Botswana
    Recruiting
    • Julius Mwita, MD, MSc · Principal investigator
  • Sociedade Hospitalar Angelina Caron
    Campina Grande do Sul, Paraná 83430-000, Brazil
    Recruiting
    • Dalton Precoma, MD · Contact
    • Dalton Precoma, MD · Principal investigator
  • HEW Cardiologia LTDA
    Joinville, Santa Catarina 89204-250, Brazil
    Recruiting
    • Conrado R. Hoffmann Filho, MD · Contact
    • Conrado R. Hoffmann Filho, MD · Principal investigator
  • InCor-HCFMUSP
    Cerqueira César, São Paulo 05403-000, Brazil
    Recruiting
    • Roney Sampaio, MD · Contact
    • Roney Sampaio, MD · Principal investigator
  • Fundação Universitária de Cardiologia mantededora do Instituto de Cardiologia e Transplantes do Distrito Federal
    Brasília, Brazil
    Recruiting
    • Kaytussia Sena · Contact
    • Adegil Silva, MD · Principal investigator
  • Hospital de Messejana
    Fortaleza, Brazil
    Recruiting
  • Dante Pazzanese Institute of Cardiology
    São Paulo, Brazil
    Recruiting
    • Mayara Silva · Contact
    • Auristela Ramos, MD · Principal investigator
  • Centro de Pesquisa Cardiolima
    Teresina, Brazil
    Recruiting
  • Coeur et Vie Clinic
    Douala, Cameroon
    Recruiting
  • St. Elizabeth Catholic General Hospital
    Kumbo, Cameroon
    Recruiting
    • Tantchou Tchoumi Jacques Cabral, MD, PhD · Principal investigator
  • Nova Scotia Health Authority
    Halifax, Nova Scotia B3S 0H6, Canada
    Recruiting
    • Robbie Stewart, MD · Principal investigator
  • Hamilton General Hospital
    Hamilton, Ontario L8L 2X2, Canada
    Recruiting
  • London Health Sciences Centre Research Inc.
    London, Ontario N6C 2R5, Canada
    Recruiting
    • Linrui Guo, MD · Contact
    • Linrui Guo, MD · Principal investigator
  • The Ottawa Hospital Research Institute
    Ottawa, Ontario K1H 8L6, Canada
    Recruiting
    • Joseph Shaw, MD · Contact
    • Joseph Shaw, MD · Principal investigator
  • Jewish General Hospital
    Montreal, Quebec H3T 1E2, Canada
    Recruiting
    • Mark Blostein, MD · Contact
  • Fuwai Hospital, CAMS & PUMC
    Beijing, China
    Recruiting
    • Xiaolu Sun, MD · Contact
    • Yan Liang, MD, PhD · Principal investigator
  • Esbjerg & Grindsted Hospital - University Hospital of Southern Denmark
    Esbjerg, Region Syddanmark 6700, Denmark
    Recruiting
    • Axel Brandes, MD · Principal investigator
  • Southern Jutland Hospital
    Aabenraa, 6200, Denmark
    Recruiting
    • Michael S Hansen, MD · Principal investigator
  • Aarhus University Hospital
    Aarhus, 8200, Denmark
    Recruiting
    • Erik Grove, MD, PhD · Principal investigator
  • Justus-Liebig-Universitat
    Giessen, Germany
    Recruiting
  • Universitätsklinikum Jena
    Jena, 07747, Germany
    Recruiting
    • Torsten Doenst, MD, PhD · Principal investigator
  • Città di Lecce Hospital
    Lecce, Apulia 73100, Italy
    Recruiting
    • Giuseppe Santarpino, MD · Principal investigator
  • AOU SS Antonio e Biagio e Cesare Arrigo
    Alessandria, Italy
    Recruiting
  • AOU delle Marche
    Ancona, Italy
    Recruiting
  • Azienda Ospedaliero Universitaria Policlinico Riuniti Foggia
    Foggia, 71122, Italy
    Recruiting
    • Domenico Paparella, MD · Principal investigator
    • Gaetano Serviddio, MD · Principal investigator
  • The Karen Hospital
    Nairobi, Kenya
    Recruiting
  • Shahid Gangalal National Heart Centre
    Kathmandu, Bagmati 44600, Nepal
    Recruiting
    • Raamesh Koirala, MD · Principal investigator
  • Nobel Medical College and Teaching Hospital
    Biratnagar, Koshi 56613, Nepal
    Recruiting
    • Rajesh Nepal, MD · Principal investigator
  • BP Koirala Institute of Health Sciences
    Dharān, Koshi 56700, Nepal
    Recruiting
    • Sanjib Kumar Sharma, MD · Principal investigator
  • National Academy of Medical Sciences, Bir Hospital
    Kathmandu, Nepal
    Recruiting
  • Erasmus University Medical Centre
    Rotterdam, 3015, Netherlands
    Recruiting
    • Jolien Roos-Hesselink, MD · Principal investigator
  • Shifa Clinical Research Center
    Islamabad, Capital Territory 44000, Pakistan
    Recruiting
    • Muhammad Asghar Nawaz, MBBS · Principal investigator
  • Meshalkin National Medical Research Center
    Novosibirsk, Russia
    Recruiting
    • Alexander Bogachev-Prokophiev, MD · Contact
  • King Faisal Specialist Hospital & Research Centre
    Riyadh, Saudi Arabia
    Recruiting
    • Eman Alrajhi, MD · Principal investigator
  • Soonchunhyang University Gumi Hospital
    Gumi, South Korea
    Recruiting
    • Hun-Gyu Hwang, MD · Contact
    • Hun-Gyu Hwang, MD · Principal investigator
  • Hospital de la Santa Creu i Sant Pau
    Barcelona, 08025, Spain
    Recruiting
    • Ekaterine Popova, MD · Contact
    • Juan Carles Souto Andres, MD · Principal investigator
  • Golden Jubilee National Hospital
    Clydebank, Glasgow G81 4HX, United Kingdom
    Recruiting
    • Nawwar Al-Attar, FRCS, FETCS, PhD · Principal investigator
  • Liverpool Heart & Chest Hospital
    Liverpool, L143PE, United Kingdom
    Recruiting
    • Bilal Kirmani, MD · Principal investigator
  • Barts Health NHS Trust
    London, United Kingdom
    Recruiting
  • South Tees Hospitals NHS Foundation Trust of The James Cook University Hospital
    Middlesbrough, United Kingdom
    Recruiting
    • Carmen Neave · Contact
    • Enoch Akowuah, MD FRCSC · Principal investigator
    • David Austin, MD · Principal investigator
  • Sheffield Teaching Hospitals
    Sheffield, United Kingdom
    Recruiting
08

References and documents

Publications

  • Puskas J, Gerdisch M, Nichols D, Quinn R, Anderson C, Rhenman B, Fermin L, McGrath M, Kong B, Hughes C, Sethi G, Wait M, Martin T, Graeve A; PROACT Investigators. Reduced anticoagulation after mechanical aortic valve replacement: interim results from the prospective randomized on-X valve anticoagulation clinical trial randomized Food and Drug Administration investigational device exemption trial. J Thorac Cardiovasc Surg. 2014 Apr;147(4):1202-1210; discussion 1210-1. doi: 10.1016/j.jtcvs.2014.01.004. Epub 2014 Jan 12. PubMed 24512654 ↗
  • Torella M, Torella D, Chiodini P, Franciulli M, Romano G, De Santo L, De Feo M, Amarelli C, Sasso FC, Salvatore T, Ellison GM, Indolfi C, Cotrufo M, Nappi G. LOWERing the INtensity of oral anticoaGulant Therapy in patients with bileaflet mechanical aortic valve replacement: results from the "LOWERING-IT" Trial. Am Heart J. 2010 Jul;160(1):171-8. doi: 10.1016/j.ahj.2010.05.005. PubMed 20598989 ↗

Individual participant data

Plan to share: No — We will establish a plan for the full-scale study but there is no plan to make IPD available to other researchers.

09

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Started Sep 2019 (actual). Primary completion is estimated for Dec 2028, 111 months after the start.

Of 45 non-industry phase 3 interventional studies under Hemorrhage, half reached primary completion within 42 months of starting (the median), counting those still running; a quarter within 26 and three quarters within 72. This study's planned 111 months is above that.

Counting every sponsor, half of 71 studies reached it within 42 months; a quarter within 26 and three quarters within 65.

How these figures are worked out, and which studies are left out of them.

Registered
Jul 25, 2018
First posted
Aug 17, 2018
StartActual
Sep 5, 2019
Primary completionEst.
Dec 31, 2028
CompletionEst.
Dec 31, 2028
Last update
Sep 17, 2026
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Sep 17, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT03636295
Responsible party
Emilie Belley-Cote (Principal Investigator, Population Health Research Institute) — Principal investigator
First posted
Aug 17, 2018
Start date
Sep 5, 2019
Primary completion
Dec 31, 2028 (estimated)
Completion
Dec 31, 2028 (estimated)
Last update
Sep 17, 2026

Study contacts

Emilie Belley-Côté, MD, MSc
Contact
emilie.belley-cote@phri.ca
905-527-4322 ext. 40306
Richard Whitlock, MD, PhD
Contact
richard.whitlock@phri.ca
905-527-4322 ext. 40306
Emilie Belley-Côté, MD, MSc
principal investigator · McMaster University

Oversight

Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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Studies of the drug tested here: Warfarin

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