PlateletsPhase 2PLTS-1NCT06147531
Delayed Cold-Stored Platelets -PLTS-1
A Phase 2 study testing Delayed Cold-Stored Buffy Coat Platelets and Room Temperature Buffy Coat Platelets in people with Platelets and Bleeding, run by University Health Network, Toronto at 2 sites in Canada.
Trial summary
PLTS-1 is a multicentre, randomized, controlled, pilot trial, using a conventional, parallel group, two-armed design at 2 cardiac surgery centres in Canada. The study is designed to assess the feasibility of a future, definitive RCT to determine the non-inferiority of cold-stored platelets compared to conventional… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Platelets, Bleeding, Cardiopulmonary Bypass
- What is being tested?
- Delayed Cold-Stored Buffy Coat Platelets and Room Temperature Buffy Coat Platelets
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 150 participants
- Where
- 2 sitesCanada
- Study dates
- 5 Jun 2024to Dec 2026
- Phase
- Phase 2
- 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
Who may be able to join
- Adult (≥18 years old) patients undergoing elective cardiac surgery with CPB will be eligible for inclusion if they are planned to undergo at least moderately complex surgery or have a preoperative platelet count ≤150,000 x106/L (this is a group at high risk of requiring platelet transfusions post-CPB).
- Moderately complex index surgery is defined as:
- repair/replacement of more than one valve;
- aorta (root/ascending/arch) replacement;
- any combination of coronary artery bypass grafting, valve repair/replacement, or aorta (root/ascending/arch) replacement; or
- re-do procedures consisting of a repair or revision of a prior cardiac intervention.
Who cannot join
- Patients will be excluded if cold-stored platelets are not going to be available at the time of surgery or if the patient:
- has a congenital or acquired hemostatic disorder (including platelet refractoriness due to anti-platelet and anti-human leukocyte antigen [HLA] antibodies) and/or requires specially matched platelets (including patients with anaphylaxis to blood due to Immunoglobulin A [IgA] deficiency),
- has known contraindications to heparin, thereby excluding cases where non-reversible anticoagulants (i.e. argatroban) are used,
- is on warfarin or direct oral anticoagulants (dabigatran, rivaroxaban, apixaban or edoxaban) within 3 days prior to surgery,
- is on antiplatelet drugs within 5 days prior to surgery (excluding acetylsalicylic acid [ASA]),
- refuses allogeneic blood products,
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- has a known pregnancy,
- has already enrolled in this study,
- is enrolled in another interventional clinical trial where routine care and management are altered,
- has hemodynamic instability defined as critical care admission, vasopressor, or inotrope dependence prior to index surgery, or
- has pre-operative requirement for, or expected post-operative dependence upon mechanical circulatory support (i.e., intra-aortic balloon pump, ventricular assist device).
Trial locations and contacts
2 sites in 1 country.
Canada2 sites
Kingston Health Sciences Centre
Kingston, Ontario, K7L 2V7
Toronto General Hospital - University Health Network
Toronto, Ontario, M5G 2C4
About this study
Official title: A Clinical Comparison of Cold-stored and Room Temperature-stored Allogeneic Platelet Transfusions in Bleeding Adult Cardiac Surgery Patients - A Randomized Multicentre Pilot Study (PLTS-1 Study)
PLTS-1 is a multicentre, randomized, controlled, pilot trial, using a conventional, parallel group, two-armed design at 2 cardiac surgery centres in Canada. The study is designed to assess the feasibility of a future, definitive RCT to determine the non-inferiority of cold-stored platelets compared to conventional platelets with respect to hemostatic effectiveness (total number of allogeneic blood products transfused within 24 hours after CPB), as well as safety.
- Conditions
- Platelets, Bleeding, Cardiopulmonary Bypass, Cardiac Surgery
- Being tested
- Delayed Cold-Stored Buffy Coat Platelets, Room Temperature Buffy Coat Platelets
- Keywords
- Blood Platelets, Cardiac surgical procedure, Blood Preservation/Methods, Blood Preservation/Adverse Effects
- Medical subject headings
- Hemorrhage
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Delayed Cold-Stored Buffy Coat PlateletsBiological
To prepare cold-stored platelets, blood banks will transition conventional room temperature platelets up to 4 days after collection (with agitation) to cold-storage (at 1-6 C without agitation) for a minimum of 1 day (24 hours) and a maximum of 10 days after collection (for a total shelf life of ≤ 14 days after collection). Thus, cold-stored platelets will be produced and stored the same way as room temperature platelets up until their transition to cold-storage, ensuring similar products differing only in storage conditions and expiration date (as cold-stored platelets will have an expiration date beyond the current 5 days for pathogen inactivated platelets or 7 days for bacterially cultured platelets). Pathogen reduced platelets will be used for the pilot study (Canada is transitioning in 2022-23 to pathogen-reduced platelets and one site has already transitioned).
Room Temperature Buffy Coat PlateletsBiological
Room temperature stored platelets are prepared from donor whole blood, which is centrifuged to collect the buffy coat layer containing platelets. Seven ABO matched buffy coats from male and/or female donors are pooled in 280 ml of platelet additive solution and split into a single dose after pathogen inactivation, resulting in a product with a final platelet count of approximately 1300 x 109. Pathogen inactivated platelets (shelf-life of 5 days, with recent Health Canada approval for an extension of the shelf-life to 7 days), will be used as Canada is transitioning in 2022-23 to pathogen-inactivated platelets and one site has already transitioned.
| Study group | Role | What they receive |
|---|---|---|
| Intervention Group | Experimental | Patients randomized to the Delayed Cold-Stored Platelet Group will receive ABO-identical buffy-coat platelets (pathogen reduced products) maintained at 22°C for up to 4 days then placed at 4°C for a minimum of 1 day (24 hours), with expiration at 14 days after collection. Receives: Biological: Delayed Cold-Stored Buffy Coat Platelets |
| Control Group | Active comparator | Those randomized to the Room Temperature Platelet Group will receive ABO-identical buffy-coat platelets (pathogen reduced products) maintained at 22°C for up to 7 days (as per current standard of care). Receives: Biological: Room Temperature Buffy Coat Platelets |
What is being measured
The primary outcome is the main question the study is designed to answer.
Feasibility Outcome 1: Adequate Patient Recruitment
Adequate recruitment (defined as ≥ 15% of eligible patients enrolled per centre per month to target consistent levels of enrollment).
Measured: through study completion, an average of 1 year.
Feasibility Outcome 2: Adequate cold-stored platelet supply
Adequate cold-stored platelet supply (defined as appropriate product available at the time of surgery for ≥90% of patients randomized to the cold-stored platelet group).
Measured: through study completion, an average of 1 year.
Feasibility Outcome 3: Adequate clinician adherence to randomization assignment.
Adequate clinician adherence to randomization assignment (defined as >90% of all randomized patients are administered the assigned product).
Measured: through study completion, an average of 1 year.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Nov 2023
- Study start5 Jun 2024
- Primary completionSep 2026 (estimated)
- Study completionDec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for PlateletsStudies of the same condition, open and under way.
- More trials run by University Health Network, TorontoThe sponsor's other registered studies.
- 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
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- PLTS-1 is a multicentre, randomized, controlled, pilot trial, using a conventional, parallel group, two-armed design at 2 cardiac surgery centres in Canada.
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 150 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Health Network, Toronto
- Sponsor type
- University, hospital or other
- Collaborators
- Kingston Health Sciences Centre, Canadian Blood Services
- Responsible party
- Sponsor
- Investigators
- Justyna Bartoszko, MD, Principal investigator, University Health Network, TorontoJeannie Callum, MD, Principal investigator, Kingston Health Sciences Centre
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06147531
- Sponsor's protocol ID
- 22-5855
- Acronym
- PLTS-1
- Status last verified
- Dec 2025
- First submitted
- 31 Oct 2023
- Last updated
- 13 Jul 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Bartoszko J, Peer M, Grewal D, Ansari S, Callum J, Karkouti K. Delayed cold-stored vs. room temperature stored platelet transfusions in bleeding adult cardiac surgery patients-a randomized multicentre pilot study (PLTS-1). Pilot Feasibility Stud. 2024 Jun 15;10(1):90. doi: 10.1186/s40814-024-01518-z.
PubMed 38879518
Study at a glance
From the registry record, last updated by the sponsor on 13 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Clinical Comparison of Cold-stored and Room Temperature-stored Allogeneic Platelet Transfusions in Bleeding Adult Cardiac Surgery Patients - A Randomized Multicentre Pilot Study (PLTS-1 Study)
- ClinicalTrials.gov ID
- NCT06147531
- Acronym / sponsor ID
- PLTS-1 / 22-5855
- Conditions
- Platelets, Bleeding, Cardiopulmonary Bypass, Cardiac Surgery
- Keywords
- Blood Platelets, Cardiac surgical procedure, Blood Preservation/Methods, Blood Preservation/Adverse Effects
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 150 participants (estimated)
- Lead sponsor
- University Health Network, TorontoUniversity, hospital or other
- Collaborators
- Kingston Health Sciences Centre, Canadian Blood Services
- Study start
- 5 Jun 2024 (actual)
- Primary completion
- Sep 2026 (estimated)
- Study completion
- Dec 2026 (estimated)
- First posted
- 27 Nov 2023 (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.
PLTS-1 is a multicentre, randomized, controlled, pilot trial, using a conventional, parallel group, two-armed design at 2 cardiac surgery centres in Canada. The study is designed to assess the feasibility of a future, definitive RCT to determine the non-inferiority of cold-stored platelets compared to conventional platelets with respect to hemostatic effectiveness (total number of allogeneic blood products transfused within 24 hours after CPB), as well as safety.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- PLTS-1 is a multicentre, randomized, controlled, pilot trial, using a conventional, parallel group, two-armed design at 2 cardiac surgery centres in Canada.
| Arm | Type | Receives |
|---|---|---|
| Intervention Group | Experimental | Biological: Delayed Cold-Stored Buffy Coat PlateletsPatients randomized to the Delayed Cold-Stored Platelet Group will receive ABO-identical buffy-coat platelets (pathogen reduced products) maintained at 22°C for up to 4 days then placed at 4°C for a minimum of 1 day (24 hours), with expiration at 14 days after collection. |
| Control Group | Active comparator | Biological: Room Temperature Buffy Coat PlateletsThose randomized to the Room Temperature Platelet Group will receive ABO-identical buffy-coat platelets (pathogen reduced products) maintained at 22°C for up to 7 days (as per current standard of care). |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Adult (≥18 years old) patients undergoing elective cardiac surgery with CPB will be eligible for inclusion if they are planned to undergo at least moderately complex surgery or have a preoperative platelet count ≤150,000 x106/L (this is a group at high risk of requiring platelet transfusions post-CPB).
- repair/replacement of more than one valve;
- aorta (root/ascending/arch) replacement;
- any combination of coronary artery bypass grafting, valve repair/replacement, or aorta (root/ascending/arch) replacement; or
- re-do procedures consisting of a repair or revision of a prior cardiac intervention.
Key exclusion criteria (11 listed)
- Patients will be excluded if cold-stored platelets are not going to be available at the time of surgery or if the patient:
- has a congenital or acquired hemostatic disorder (including platelet refractoriness due to anti-platelet and anti-human leukocyte antigen [HLA] antibodies) and/or requires specially matched platelets (including patients with anaphylaxis to blood due to Immunoglobulin A [IgA] deficiency),
- has known contraindications to heparin, thereby excluding cases where non-reversible anticoagulants (i.e. argatroban) are used,
- is on warfarin or direct oral anticoagulants (dabigatran, rivaroxaban, apixaban or edoxaban) within 3 days prior to surgery,
- is on antiplatelet drugs within 5 days prior to surgery (excluding acetylsalicylic acid [ASA]),
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Delayed Cold-Stored Buffy Coat PlateletsTo prepare cold-stored platelets, blood banks will transition conventional room temperature platelets up to 4 days after collection (with agitation) to cold-storage (at 1-6 C without agitation) for a minimum of 1 day (24 hours) and a maximum of 10 days after collection (for a total shelf life of ≤ 14 days after collection). Thus, cold-stored platelets will be produced and stored the same way as room temperature platelets up until their transition to cold-storage, ensuring similar products differing only in storage conditions and expiration date (as cold-stored platelets will have an expiration date beyond the current 5 days for pathogen inactivated platelets or 7 days for bacterially cultured platelets). Pathogen reduced platelets will be used for the pilot study (Canada is transitioning in 2022-23 to pathogen-reduced platelets and one site has already transitioned). | Biological | Intervention Group |
| Room Temperature Buffy Coat PlateletsRoom temperature stored platelets are prepared from donor whole blood, which is centrifuged to collect the buffy coat layer containing platelets. Seven ABO matched buffy coats from male and/or female donors are pooled in 280 ml of platelet additive solution and split into a single dose after pathogen inactivation, resulting in a product with a final platelet count of approximately 1300 x 109. Pathogen inactivated platelets (shelf-life of 5 days, with recent Health Canada approval for an extension of the shelf-life to 7 days), will be used as Canada is transitioning in 2022-23 to pathogen-inactivated platelets and one site has already transitioned. | Biological | Control Group |
Primary outcome
Feasibility Outcome 1: Adequate Patient Recruitment
Time frame: through study completion, an average of 1 year.
Adequate recruitment (defined as ≥ 15% of eligible patients enrolled per centre per month to target consistent levels of enrollment).
Feasibility Outcome 2: Adequate cold-stored platelet supply
Time frame: through study completion, an average of 1 year.
Adequate cold-stored platelet supply (defined as appropriate product available at the time of surgery for ≥90% of patients randomized to the cold-stored platelet group).
Feasibility Outcome 3: Adequate clinician adherence to randomization assignment.
Time frame: through study completion, an average of 1 year.
Adequate clinician adherence to randomization assignment (defined as >90% of all randomized patients are administered the assigned product).
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 13 Jul 2026.
- Derived from this study: PubMed 38879518Bartoszko J, Peer M, Grewal D, Ansari S, Callum J, Karkouti K. Delayed cold-stored vs. room temperature stored platelet transfusions in bleeding adult cardiac surgery patients-a randomized multicentre pilot study (PLTS-1). Pilot Feasibility Stud. 2024 Jun 15;10(1):90. doi: 10.1186/s40814-024-01518-z.
- Individual participant dataSharing planned: No
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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. This study is not recruiting at the moment.
Justyna Bartoszko, MD principal investigator
University Health Network, Toronto
Jeannie Callum, MD principal investigator
Kingston Health Sciences Centre
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Delayed Cold-Stored Buffy Coat Platelets and Room Temperature Buffy Coat Platelets in people with Platelets and Bleeding, run by University Health Network, Toronto at 2 sites in Canada.
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 6 inclusion and 11 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: under way, not looking for participants, as of the sponsor's last update on 13 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Canada. 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.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
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?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Feasibility Outcome 1: Adequate Patient Recruitment (time frame: through study completion, an average of 1 year.). The study lists 3 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 NCT06147531, which also lists 1 linked publication.
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 13 Jul 2026; AzTrials last refreshed its copy on 28 Oct 2026.