# Centrifugation versus filtration-based cell salvage: impact on perioperative bleeding in cardiac surgery-the COLTRANE randomised clinical trial – study protocol

Antoine Beurton, Alexandre Mansour, Antoine Bénard, Mathieu Pernot, Victor-Emmanuel Brett, Corinne Batsale, Anaïs Aitgougam, Anais Cordon, Christine Mouton, Aurelie Fresselinat, et al.

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## To cite this version:

Antoine Beurton, Alexandre Mansour, Antoine Bénard, Mathieu Pernot, Victor-Emmanuel Brett, et al.. Centrifugation versus filtration-based cell salvage: impact on perioperative bleeding in cardiac surgery-the COLTRANE randomised clinical trial - study protocol. BMJ Open, 2025, 15 (7), pp.e099423. 10.1136/bmjopen-2025-099423xx. hal-05239790

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# BMJ Open Centrifugation versus filtration-based cell salvage: impact on perioperative bleeding in cardiac surgery—the COLTRANE randomised clinical trial – study protocol

Antoine Beurton,¹,² Alexandre Mansour,³ Antoine Benard,⁴ Mathieu Pernot,⁵ Victor-emmanuel Brett,⁶ Corinne Batsale,¹ Anais Aitgouam,⁷ Anais Cordon,⁴ Christine Mouton,⁶ Aurelie Fresselinat,⁷ Geraldine Robert,⁸ Julien Imbault,¹,² Nicolas Nesseler,³ Alexandre Ouattara¹,²

**To cite:** Beurton A, Mansour A, Benard A, et al. Centrifugation versus filtration-based cell salvage: impact on perioperative bleeding in cardiac surgery—the COLTRANE randomised clinical trial – study protocol. *BMJ Open* 2025;15:e099423. doi:10.1136/bmjopen-2025-099423

► Prepublication history and additional supplemental material for this paper are available online. To view these files, please visit the journal online (https://doi.org/10.1136/bmjopen-2025-099423).

Received 17 January 2025
Accepted 27 June 2025

## ABSTRACT

**Introduction** Cardiac surgery remains a high-risk procedure for bleeding despite advances in patient blood management. Conventional centrifugation-based autotransfusion devices primarily recover red blood cells, losing platelets and coagulation factors. The SAME autotransfusion device (i-SEP, Nantes, France) introduces an innovative filtration-based approach, recovering erythrocytes, leucocytes and platelets to enhance perioperative haemostasis. The main objective is to determine whether the filtration-based SAME device reduces significant perioperative bleeding compared with the centrifugation-based system in high-risk cardiac surgery patients.

**Methods and analysis** The Centrifugation-based vs filtration-based intraOperative cell saLvage on qualiTy of peRiOpeRative haemostasis iN cardiac surgEry (COLTRANE) trial is a multicentre, parallel-group, single-blinded, superiority-randomised clinical trial. Conducted over 19 months in 10 French hospitals, the study will target patients at high risk of bleeding undergoing on-pump cardiac surgery via sternotomy. A total of 570 patients (285 per group) are required to achieve 80% statistical power for detecting clinically significant differences. Eligible patients will be randomised to either a centrifugation-based or filtration-based autotransfusion group. Both groups will follow standardised perioperative and cardiopulmonary bypass management, with the devices used only intraoperatively. The primary outcome is the proportion of patients with clinically significant perioperative bleeding defined as classes 2 to 4 of the Universal Definition of Perioperative Bleeding. The secondary outcomes include device efficiency and safety, perioperative haemostasis, lengths of intensive care unit and hospital stays, early postoperative morbidity and 30-day all-cause mortality. Ancillary studies will be performed to evaluate cell recovery and washing performance, the viscoelastic properties of retransfused blood (Quantra Qplus; Stago, Asnières-sur-Seine, France), and the effect of salvaged leucocytes on postoperative inflammation and immune function.

## STRENGTHS AND LIMITATIONS OF THIS STUDY

⇒ This study will compare the impact of intraoperative use of a filtration-based autotransfusion device with a centrifugation-based autotransfusion device on the quality of perioperative haemostasis.

⇒ The COLTRANE trial's primary endpoint is a pragmatic, clinically meaningful measure aimed at reducing severe perioperative bleeding, as defined by the Universal Definition of Perioperative Bleeding.

⇒ The trial's focus on high-risk cardiac surgery patients ensures rigorous testing of the device's effectiveness, although this may limit its generalisability to lower-risk populations.

⇒ While the multicentre design is a strength, conducting the trial exclusively in high-volume academic centres likely limits its broader applicability.

⇒ Patients will be blinded, although medical staff will not be; however, transfusion protocols are in place to help mitigate this potential source of bias.

**Ethics and dissemination** This trial has received a favourable opinion from the Committee for the Protection of Persons and authorisation from the French authorities (Comité de protection des personnes Nord Quest, IDRCB: 2023-A02566-39). Protocol V.1.1 was approved on 22 January 2024. The trial is registered on ClinicalTrials.gov (NCT06425614). The findings will be disseminated through oral communications at national and international scientific meetings and peer-reviewed journal publications. Individual participant data will be made available on reasonable request to qualified researchers, following review and approval by the study sponsor and ethics committee.

**Trial registration number** ClinicalTrials.gov, NCT06425614.

## INTRODUCTION

Despite significant advances in patient blood management, cardiac surgery is still associated

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© Author(s) (or their employer(s)) 2025. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ Group.

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**Correspondence to**
Dr Antoine Beurton;
antoine.beurton@chu-bordeaux.fr
a

with a high risk of bleeding, which poses a considerable challenge to medical and surgical teams. Perioperative bleeding is frequently managed with allogeneic blood products, making cardiac surgery one of the procedures with the highest rates of blood transfusion.¹²

The mechanisms underlying perioperative bleeding in cardiac surgery are multifactorial and include impaired thrombin generation, altered fibrin formation and qualitative or quantitative platelet defects.³⁻⁵ However, there is currently no universally accepted definition of perioperative bleeding in cardiac surgical procedures.⁶ Previous clinical trials have reported a variety of outcomes, including allogeneic transfusion exposure, sternal closure time, weight of surgical gauze, postoperative blood loss measured from chest drainage, re-exploration for bleeding or a combination of these metrics in clinical composite bleeding scores.¹⁶⁻⁸ Among the bleeding scores available, the Universal Definition of Perioperative Bleeding (UDPB) classification is considered the most clinically relevant.¹

Large cardiac surgical databases indicate that significant perioperative bleeding, as defined by the UDPB (moderate to massive bleeding, classes 2 to 4), occurs in 34%–72% of cases.¹⁸ ⁹ Furthermore, up to 5% of patients require surgical re-exploration for bleeding.¹⁸ ⁹ Implementation of standardised perioperative management algorithms, including blood transfusion protocols, plasma-derived products and point-of-care coagulation assays, has been shown to reduce bleeding, transfusions and the need for re-exploration in cardiac surgical patients.¹⁸⁻¹⁰

Several studies have demonstrated that both blood product transfusion and re-operation for excessive bleeding in cardiac surgery are significantly associated with adverse clinical outcomes and increased morbidity and mortality.¹ ¹¹⁻¹³ Consequently, numerous strategies have been developed to limit perioperative bleeding and minimise the use of blood products, with intraoperative cell salvage emerging as a key component.¹⁴ ¹⁵ Commercially available centrifugation-based autotransfusion devices concentrate and wash red blood cells salvaged from the surgical field before reinfusing them into the patient.¹⁶ However, these devices recover only red blood cells, with platelets and coagulation factors being almost entirely lost during the process.¹⁷

The innovative SAME autotransfusion device (i-SEP, Nantes, France) uses hollow-fibre filtration technology to provide a balanced approach, recovering both red blood cells and platelets while removing plasma components.¹⁸ Preliminary studies have yielded promising results, with clinical trials confirming the safety and reliability of this device.¹⁸ ¹⁹ With a fast processing time (< 5 min), the device has been shown to recover 86% of red blood cells with minimal haemolysis and 52% of platelets with optimal platelet activation.¹⁹

The purpose of the Centrifugation-based vs filtration-based intraOperative cell saLvage on qualiTy of peRiOpeRAtive haemostasis iN cardiac surgEry (COLTRANE)

trial is to test the hypothesis that intraoperative use of the SAME filtration-based autotransfusion device can improve perioperative haemostasis, thereby reducing the proportion of patients that experience clinically significant perioperative bleeding defined as classes 2 to 4 of UDPB.¹

## METHODS AND DESIGN

### Study setting

This will be the first randomised trial to evaluate the superiority of the SAME filtration-based autotransfusion device compared with centrifugation-based autotransfusion devices in patients undergoing on-pump cardiac surgery who are at high risk of bleeding. We will conduct a single-blind (patient), parallel-group, randomised clinical-superiority trial.

The primary objective of the COLTRANE trial is to compare the impact of intraoperative use of a filtration-based autotransfusion device (SAME i-SEP) with a centrifugation-based autotransfusion device (commonly used in clinical centres) on the quality of perioperative haemostasis in adult cardiac surgery patients. The quality of perioperative haemostasis will be assessed using the UDPB classification, which considers blood loss within the first 12 postoperative hours and perioperative blood product use within the first postoperative day. The secondary objectives of the COLTRANE trial are to compare the efficiency and safety of filtration-based and centrifugation-based devices in terms of the overall quality of perioperative haemostasis (all components of the UDPB classification), perioperative biological haemostasis and complete blood count, length of stays in the intensive care unit and hospital and early postoperative outcomes, including 30-day postoperative morbidity and all-cause mortality. Additionally, the trial will estimate the cost-benefit of the filtration-based SAME device compared with centrifugation-based devices from the perspective of hospital centres.

Three ancillary studies in limited patient groups will be conducted. The first ancillary study, involving 120 patients (60 per arm) at four sites, will compare cell-recovery and washing efficiency between the SAME i-SEP device and centrifugation-based devices (figure 1). The second ancillary study, involving 120 patients (60 per arm) at four sites, will use sonorheometry with the Quantra Qplus System (Stago, Asnières-sur-Seine, France) to assess the impact of retransfused blood on the viscoelastic properties of blood (figure 2). The third ancillary study, involving 30 patients (15 per arm) at two sites, will explore the effects of salvaged leucocytes on inflammation and immune function (figure 3). Blood samples will be collected before and after processing for immunological assessment, with additional samples being obtained at specific time points during and after surgery.

### Eligibility criteria

The inclusion criteria will encompass adult patients aged ≥18 years undergoing on-pump cardiac surgery with a
Ancillary study 1
Cell recovery and washing performance

<figure><img src="image_4.png" /><figcaption>**Figure 1** Ancillary study 1 timeline. C1, first treatment cycle; C2, second treatment cycle; CPB, cardiopulmonary bypass; OR In, operating room entrance; OR Out, operating room exit.</figcaption></figure>

high risk of bleeding and an indication for autotrans-
fusion. Patients will be required to provide informed
written consent prior to any research examinations, with
consent obtained no later than on the day of inclusion.
High risk of bleeding will be defined by specific criteria,
including primary or redo combined cardiac proce-
dures (involving two or more valves, valve and coronary
artery bypass grafting), primary or redo ascending aorta
surgery,²⁰⁻²³ and primary or redo isolated coronary artery
bypass grafting (CABG) with three or more bypasses
using the internal mammary artery.²⁴ The definition of
‘high risk of bleeding’ used in our study was not directly
based on the calculation of existing predictive scores.

Nonetheless, several of these scores consider combined
cardiac surgeries and procedures involving the ascending
aorta as significant predictors of major bleeding and
surgical re-exploration.²⁰⁻²³ ²⁵ These operations are also
generally associated with prolonged cardiopulmonary
bypass time, which is itself an independent risk factor for
severe bleeding.

Regarding isolated CABG procedures, we chose to
include only patients undergoing three or more grafts.
Indeed, these patients have been previously identified
as having a higher likelihood of re-intervention due to
bleeding, according to published data.¹¹ ²⁴ ²⁵

Ancillary study 2
Impact of retransfused blood in vivo blood viscoelastic properties (SEER)

<figure><img src="image_5.png" /><figcaption>**Figure 2** Ancillary study 2 timeline. CPB, cardiopulmonary bypass; OR In, operating room entrance; OR Out, operating room exit.</figcaption></figure>
<figure><img src="image_6.png" /></figure>

Ancillary study 3
Impact of filtration and centrifugation-based autotransfusion device on salvaged leukocytes

<figure><img src="image_7.png" /><figcaption>**Figure 3** Ancillary study 3 timeline. C1, first treatment cycle; CPB, cardiopulmonary bypass; OR In, operating room entrance; OR Out, operating room exit.</figcaption></figure>

Exclusion criteria

Patients will be excluded if they meet any of the following criteria: uninterrupted preoperative therapy with P2Y12 receptor inhibitors (last intake before surgery: 5 days for clopidogrel, ticagrelor and ticlopidine; 7 days for prasugrel; 1 hour for cangrelor); uninterrupted preoperative treatment with anti-coagulant drugs (last intake before surgery: 5 days for vitamin K antagonists, 4 days for dabigatran, 3 days for rivaroxaban and apixaban, 24 hours for therapeutic low-molecular-weight heparin, 36 hours for therapeutic fondaparinux, 12 hours for prophylactic low-molecular-weight heparin, 24 hours for prophylactic fondaparinux and 4 hours for unfractionated heparin); sepsis; malignant tumours; immunocompromised status (defined as steroid or immunosuppressive therapy, ongoing treatment for solid tumours or haematological malignancies, primary immunodeficiency disorders or AIDS); emergency cardiac surgery; heart transplantation; implantation or presence of a ventricular assist device; two or more previous sternotomies; surgical procedures requiring circulatory arrest and/or profound hypothermia (<32°C); active infective endocarditis; cardiac surgery for benign or malignant cardiac tumours; known acquired or constitutional coagulopathy requiring specialist management; end-stage renal disease (on chronic dialysis); profound anaemia (haemoglobin of <10 g/dL); severe thrombocytopaenia (platelet count of <100 × 10⁹/L); participation in another interventional research study with an ongoing exclusion period, pregnancy or breastfeeding; judicial protection status; or deprivation of liberty.

Randomisation and blinding

The randomisation list, created by a biostatistician at the
Methodology and Data Management Centre, follows a 1:1
allocation ratio and will be kept confidential and secure.

Randomisation is stratified by centre, and the process
is detailed in the protocol. The study is single-blinded
to maintain the confidentiality of allocation groups. To
ensure blinding, randomisation will be conducted 1 day
prior to surgery by a clinical research assistant using a
secure electronic case report form (eCRF). The result
will then be provided to the attending anaesthetist, who
will prepare the device without disclosing the allocation.
To preserve blinding, a surgical drape will be placed
over the device until the patient loses consciousness.
Furthermore, the type of autotransfusion device used
(SAME or centrifugation-based) will not be mentioned
in the surgical report, and patients will be informed of
this procedure before providing consent. Unblinding
can occur, if necessary, at the end of the follow-up period
when the surgical report is shared with the patient and
their general practitioner. If a participant requests to
know their treatment group before the follow-up period
concludes, the investigator will explain the importance of
maintaining blinding. If the participant persists in their
request, the investigator will reveal the allocation and
document the unblinding in the eCRF.

Interventions

After baseline screening, cardiac surgery patients meeting the eligibility criteria will be invited to participate in the study. Written informed consent will be obtained by the anaesthetist during the preoperative consultation and/or visit, which will occur no more than 3 weeks before surgery. Eligible patients will then be randomised into one of two groups: centrifugation-based or filtration-based autotransfusion

Except for the type of autotransfusion device used,
perioperative management will be identical in the two
groups. The management of cardiopulmonary bypass
will be standardised under normothermia or moderate
<figure><img src="image_8.png" /><figcaption>**Figure 4** Transfusion algorithm. ACT, Activated clotting time, APTT, Activated partial thromboplastin time, CPB, cardiopulmonary bypass; FFP, fresh frozen plasma; PCC, prothrombin complex concentrate; PT, prothrombin time, RBC, red blood cell.</figcaption></figure>
<table><caption>**Figure 5** Classes of perioperative bleeding adapted from the Universal Definition of Perioperative Bleeding (UDPB). FFP, fresh frozen plasma; N/A, not applicable; PCCs, prothrombin complex concentrates; PLT, platelet concentrates; PRCB, packed red blood cells; rFVIIa, recombinant activated factor VII. The presence of only one predefined attribute is sufficient to define the category of perioperative bleeding. *Please note that intra- and postoperative use of blood products and haemostatic factors were considered for the calculation of UDPB score.</caption><thead><tr><th rowspan="2">Bleeding score</th><th rowspan="2">Sternal closure delayed</th><th rowspan="2">Postoperative chest tube blood loss over 12 hours (mL)</th><th colspan="6">Perioperative use of blood products and haemostatic factors*</th><th rowspan="2">Re-exploration/ tamponnade</th></tr><tr><th>PRBC (units)</th><th>FFP (units)</th><th>PLT (units)</th><th>Fibrinogen concentrate</th><th>PCCs</th><th>rFVIIa</th></tr></thead><tbody><tr><td>Class 0 (insignificant)</td><td>No</td><td>&lt; 600</td><td>0</td><td>0</td><td>0</td><td>No</td><td>No</td><td>No</td><td>No</td></tr><tr><td>Class 1 (mild)</td><td>No</td><td>600-800</td><td>1</td><td>0</td><td>0</td><td>No</td><td>No</td><td>No</td><td>No</td></tr><tr><td>Class 2 (moderate)</td><td>No</td><td>801-1000</td><td>2-4</td><td>Yes</td><td>Yes</td><td>Yes</td><td>Yes</td><td>No</td><td>No</td></tr><tr><td>Class 3 (severe)</td><td>Yes</td><td>1001-2000</td><td>5-10</td><td>5-10</td><td>N/A</td><td>N/A</td><td>N/A</td><td>No</td><td>Yes</td></tr><tr><td>Class 4 (massive)</td><td>N/A</td><td>&gt; 2000</td><td>&gt;10</td><td>&gt;10</td><td>N/A</td><td>N/A</td><td>N/A</td><td>Yes</td><td>N/A</td></tr></tbody></table>

hypothermia. Any blood shed from the surgical site and the residual cardiopulmonary bypass circuit volume will be processed by the intraoperative cell salvage machine and subsequently retransfused. In both groups, the auto-transfusion device will not be used postoperatively.

Allogeneic transfusion of blood products will follow a protocol based on recent guidelines (figure 4). The decision to re-explore patients for excessive bleeding will remain at the discretion of the attending physicians. The use of blood products may also be guided by findings from viscoelastic haemostatic assays, when available at the study site. The use of intraoperative cell salvage throughout the entire surgical procedure remains a topic of debate. Some authors have raised concerns about the risk of coagulopathy associated with the re-transfusion of large volumes of salvaged blood.17 26 However, direct suction of shed blood from the surgical field into the CPB reservoir has also been linked to significant drawbacks.27-29 In light of these considerations, we have followed the most recent guidelines, which support the use of intraoperative cell salvage as the preferred strategy during surgery, rather than relying on direct suction into the CPB circuit.15 30 Because of concerns regarding the re-transfusion of activated and inflammatory blood components potentially associated with coagulopathy, and in accordance with recent guidelines, cell salvage will not be used in the ICU.15

## Outcomes

Among the available bleeding scores, the UDPB classification is considered the most clinically relevant because it is easily applicable at the patient's bedside (figure 5). The timing of intraoperative blood product use will be documented in the patient's file, specifying whether the products were administered before or after chest closure. Using a validated and standardised scale to measure the primary endpoint will enhance the validity of the trial. Additionally, all elements of the UDPB classification can

be readily monitored because they are routinely recorded in medical and surgical files.

## Participant timeline

A timeline is presented in figure 6.

## Sample size

Based on several large, non-selected cohorts of cardiac surgical patients in whom the incidence of significant bleeding events (UDPB classes 2-4) ranged from 34% to 53% (eg, Dyke et al, Bartoszko et al), and given that our project plans to include selected patients at high risk for bleeding (eg, combined procedures, ascending aorta, ≥ 3 bypass grafts), we estimated the proportion of patients with significant bleeding (UDPB classes 2-4) to be approximately 60%.18 Considering that the SAME device allows a platelet recovery of 51% and that the proportion of patients in UDPB classes 2-4 observed in our feasibility i-TRANSEP study conducted in selected low-risk patients was 32%, we estimated that a 20% relative reduction in the proportion of patients with significant bleeding would be a clinically meaningful target.19 Therefore, we calculated that a sample size of 270 patients per group would provide an 80% chance (power=0.80) of detecting a significant difference between the two treatment groups, with a two-sided type I error of 0.05. To account for an anticipated 5% loss to follow-up, we aimed to recruit a total of 285 patients per group. UDPB class 2 marks the threshold at which patients begin to receive haemostatic transfusions, such as platelets, FFP, PCC or fibrinogen concentrates. For this reason, we considered it clinically relevant to include class 2 in our definition of significant bleeding, particularly because the tangential flow filtration technology used by the SAME device is designed to preserve functional platelets.

## Recruitment

To ensure the feasibility of the study, we are preferentially including tertiary care teaching hospitals that routinely use
<table><caption>**Figure 6** Patient timeline. ICU, intensive care unit; LOS, length of stay; LVAD, left ventricular assist device; MV, mechanical ventilation; RRT, renal replacement therapy; RVAD, right ventricular assist device; SAPS II, Simplified Acute Physiology Score II; SOFA, Sequential Organ Failure Assessment; STMCS, short-term mechanical circulatory support; UDPB, Universal Definition of Postoperative Bleeding. VV-ECMO, veno-venous extracorporeal membrane oxygenation.</caption><thead><tr><th rowspan="3">TIMEPOINTS</th><th colspan="10">STUDY PERIOD</th></tr><tr><th rowspan="2">Baseline</th><th colspan="2">Surgery</th><th colspan="5">Intensive care unit and hospital</th><th rowspan="2">Discharge visit D5 to D30</th><th rowspan="2">Last visit D30 ± 2</th></tr><tr><th>Before incision</th><th>Post-protamine</th><th colspan="2">D0</th><th rowspan="2">D1</th><th rowspan="2">D2</th><th rowspan="2">D3 to D5</th></tr><tr><th></th><th></th><th></th><th>0 to H6*</th><th>H12</th><th></th><th></th><th></th><th></th><th></th></tr></thead><tbody><tr><td><strong>ENROLLMENT:</strong></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Eligibility Screen</td><td>X</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Informed Consent</td><td>X</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Allocation</td><td></td><td>X</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td><strong>INTERVENTIONS:</strong></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>SAME or conventional device</td><td></td><td></td><td>X</td><td>X</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td><strong>ASSESSMENTS:</strong></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td><strong>Baseline characteristics</strong></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Laboratory tests</td><td></td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td></td><td></td></tr><tr><td>Surgery data, Autotransfusion device data</td><td></td><td></td><td></td><td>X</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td><strong>Primary outcome: UDPB classification</strong></td><td></td><td></td><td></td><td></td><td></td><td></td><td>X</td><td></td><td></td><td></td></tr><tr><td>Volume of blood loss</td><td></td><td></td><td></td><td></td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td></td></tr><tr><td>Surgical re-exploration, Stemal closure delayed</td><td></td><td></td><td></td><td></td><td>X</td><td></td><td>X</td><td>X</td><td>X</td><td></td></tr><tr><td>SOFA score</td><td></td><td></td><td></td><td></td><td></td><td></td><td>X</td><td>X</td><td>X</td><td></td></tr><tr><td>SAPS II score</td><td></td><td></td><td></td><td></td><td></td><td></td><td>X</td><td></td><td></td><td></td></tr><tr><td>ICU and Hospital LOS, VM duration</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td>X</td></tr><tr><td>Concomitant medications</td><td></td><td></td><td>X</td><td>X</td><td></td><td></td><td>X</td><td>X</td><td>X</td><td>X</td></tr><tr><td>STMCS, VV-ECMO, RRT, MV status</td><td></td><td></td><td></td><td></td><td>X</td><td></td><td>X</td><td>X</td><td>X</td><td>X</td></tr><tr><td>LVAD or RVAD implantation</td><td></td><td></td><td></td><td></td><td></td><td></td><td>X</td><td>X</td><td>X</td><td>X</td></tr><tr><td>Vital, ICU and hospital discharge status, adverse events</td><td></td><td></td><td>X</td><td>X</td><td></td><td></td><td>X</td><td>X</td><td>X</td><td>X</td></tr></tbody></table>

intraoperative cell salvage and hospitalise patients at high risk of bleeding. Only high-volume centres have been selected, and 10 sites have agreed to participate in the project. Based on an analysis of their 2021 local databases, each site is expected to perform more than 1000 on-pump cardiac surgeries during the study period. Of these cases, the number of eligible patients per month is projected to be 17–43. Considering the required sample size of 570 patients, an average of approximately four patients meeting the inclusion criteria per month per centre will need to be enrolled. The anticipated number of eligible patients reported by each site significantly exceeds this threshold, making the COLTRANE trial highly feasible.

## METHODS: DATA COLLECTION, MANAGEMENT AND ANALYSIS

### Data collection methods

All essential protocol-related information will be accurately recorded in eCRF, with explanations provided for any missing data. Data will be collected promptly and entered into the eCRF in a clear and legible manner. A clinical research associate, appointed by the sponsor, will conduct regular site visits during the initiation, course and conclusion of the study. These visits will assess informed consent, protocol compliance, data quality (completeness, accuracy, consistency with source documents) and, if applicable, product management. Each visit will generate a monitoring report. Data management will use the REDCap software, coupled with a dedicated MySQL database.

### Data management

Regular checks will be conducted to ensure data consistency and completeness in the eCRF, following a defined set of checks outlined in the data validation plan created by the coordinating investigator and the Clinical Epidemiology Unit's project team. The data manager will generate and manage queries, which will be transmitted to the investigative sites through the eCRF. The investigation team will address and correct issues raised by these queries. Prescribed treatments and clinical events will be coded in the eCRF to facilitate data verification and analysis. Medical terms and drug classifications will be coded using the following dictionaries: the ongoing version of MedDRA and ATC (Anatomical Therapeutic Chemical Classification System) codes.

### Statistical methods

The primary endpoint of this study is the proportion of patients experiencing moderate to massive perioperative bleeding in the two groups. The trial is designed as a superiority trial using a two-sided test. We cannot rule out the possibility that the comparison groups may not be balanced, despite well-conducted randomisation. Furthermore, randomisation is stratified by study centre. Consequently, between-group comparisons will be performed using a logistic regression model adjusted for investigating centres and other potential confounding variables, including the use of a cell-saver device. The model will be assessed for compliance with assumptions, such as the log-linearity of associations.
The primary analysis will be conducted with a type I error rate of 5%. For secondary analyses, the multiplicity of statistical tests will be addressed by controlling the false discovery rate using the Benjamini-Hochberg procedure. Statistical methods for comparing secondary endpoints will be chosen based on the nature of the variables.

Quantitative variables will be compared using a Student's t-test, Welch's t-test (for unequal variances) or the non-parametric Wilcoxon test, depending on the assumptions applicable to each test. A linear regression model may also be used to adjust for confounding variables. Assumptions of normality and linearity for quantitative factors will be systematically verified, and data transformations may be applied if assumptions are violated.

Qualitative variables will be compared using a χ2 test, a corrected χ2 test or Fisher's exact test, depending on the data distribution and the assumption of independence. Logistic regression models may be employed to adjust for confounding variables. Assumptions regarding normality and linearity for quantitative factors will also be systematically verified.

The analyses will initially follow the intent-to-treat principle, incorporating all randomised participants into their originally assigned groups and using all their data, regardless of any subsequent changes during the study. Subsequently, an 'under-treatment analysis' will be conducted, grouping participants based on the treatment they received. Exclusions from the analysis will apply only to patients meeting specific conditions, including those who never adhered to the study strategy (if unaware of their randomised group), individuals inappropriately included due to unsigned consent, patients mistakenly included without meeting essential eligibility criteria and those who withdraw their informed consent. Decisions regarding exclusion will be determined by the Scientific Committee, which will remain blinded to the strategy group and patients' progress post-inclusion. With the exception of these exclusions, all patients will be included in the analysis, including those lost to follow-up, those who interrupt treatment and those who exit the study.

## Missing data

For each variable, the number of missing data points will be described. The reasons for missing data will be documented whenever possible to aid in the interpretation of results. Missing data for the primary endpoint will be handled through multiple imputation.

## Methods: monitoring

### Data monitoring

An independent data and safety monitoring board (DSMB) has been established for this project and is authorised to provide any recommendations to the sponsor that it deems appropriate based on the accumulated data. The DSMB comprises a cardiac surgeon, a cardiac anaesthetist and a clinical epidemiologist and serves as an advisory body to the coordinating investigator and the scientific committee, offering guidance on

various aspects of the research. The DSMB's responsibilities include advising on potential early termination of the study due to toxicity, operational issues or sufficient data collection; providing recommendations on significant protocol modifications related to recruitment, follow-up or emerging scientific evidence. The DSMB has access to all data that would be judged useful, with its primary role being the assessment of clinical outcomes and the provision of recommendations regarding the continuation, discontinuation or modification of the trial. It also addresses matters related to scientific and ethical integrity and trial safety, delivering written recommendations to the Scientific Committee after each meeting.

## Harms

Autotransfusion devices carry potential risks, including coagulation disorders, air embolism, pulmonary complications, haemolysis (leading to excessive free haemoglobin, haematuria, haemoglobinuria and hyperkalaemia), septicaemia and thrombosis. Auxiliary medicinal products may also cause adverse effects, as outlined in their summaries of product characteristics. The disease under study is associated with inherent risks such as disease-related death and relapse. Surgery-related risks include bleeding, cardiac tamponade, cardiac rhythm disorders, atrioventricular blocks, cerebrovascular accidents, myocardial infarction, mesenteric ischaemia, other thromboembolic events, acute renal failure, acute respiratory distress, hypotension, low cardiac output, infections, epilepsy, confusion and liver dysfunction. Because the aim of the COLTRANE study was not to establish the safety profile of the filtration-based SAME device—which received CE marking in 2022—but, rather, to compare the two autotransfusion procedures in the context of cardiac surgery with cardiopulmonary bypass, our eCRF is designed to collect adverse events graded 3 or above according to the Common Terminology Criteria for Adverse Events scale, V.5.0. Investigators are required to report the following two types of adverse events to the safety and vigilance unit: adverse events of special interest (ie, gas embolisms, haemolysis, septicaemia and acute kidney injury [KDIGO stage 2 to 3]) and all serious adverse events as defined by Article R1123-46 of the French Public Health Code and the ICH-E2B guideline (ie, any adverse reaction or event that results in death, is life-threatening, requires hospitalisation or prolongation of hospitalisation, causes significant or long-term disability or incapacity, results in a congenital anomaly or birth defect or is otherwise considered medically serious, including in relation to a drug regardless of the administered dose).

## Auditing

Subject to reasonable advance notice, an audit may be conducted at any time by individuals appointed by the sponsor who are independent of the research team. An inspection may also be carried out by a competent authority, such as the Agence Nationale de Sécurité du Médicament et des Produits de Santé (ANSM).
# ETHICS AND DISSEMINATION

## Research ethics approval

The sponsor and investigators commit to ensuring that this research is conducted in accordance with Law No. 2012-300 of 5 March 2012 and Decree No. 2016-1537 of 16 November 2016 on research involving human participants, as well as in compliance with Good Clinical Practices (ICH GCP E6(R2), 9 November 2016) and the Declaration of Helsinki. This trial is being conducted in accordance with the approved protocol. The research has received a favourable opinion from the Committee for the Protection of Persons, and authorisation from the ANSM (number: 2023-A02566-39) (Supplementary digital content).

## Protocol amendments

The scientific committee is responsible for making decisions on all changes to the protocol necessary for the progress of the research, particularly protocol amendments, prior to their submission to the French ethics committee (CPP) and the regulatory authority (ANSM). Following each meeting, the president of the scientific committee must inform the sponsor (University Hospital of Bordeaux) of the decisions made. Any decisions involving a major amendment or financial change must be approved by the sponsor. All protocol changes must be communicated to the investigators participating in the research, who agree to adhere to the revised content.

## Consent

During the pre-inclusion or inclusion visit, the investigator will inform the participant and address all questions regarding the purpose, nature of the constraints, foreseeable risks and expected benefits of the research. The investigator will also explain the participant's rights in the context of research involving human subjects and verify the eligibility criteria. The investigator will provide each participant with a copy of the information notice and consent form, and an example of this consent form is available in the online supplemental material. Following this information session, the participant will be given a reflection period. The investigator will be responsible for collecting the participant's informed consent. The consent form must be signed before any clinical or paraclinical examinations required by the research are conducted. If the participant agrees to take part, both the participant and the investigator will clearly print their names and surnames, date the form and sign two original copies.

## Confidentiality

In accordance with the applicable legislative provisions, individuals with direct access to source data will take all necessary precautions to maintain the confidentiality of information related to investigational medicinal products, research and participants, particularly concerning their identity and the results obtained. These individuals, including the investigators, are bound by professional

confidentiality obligations. During the research and on its conclusion, data collected on participants and submitted to the sponsor by the investigators (or any other specialised contributor) will be anonymised. The data will not explicitly reference the participants' names or addresses. Each participant will be assigned a confidential identification code comprising the investigational site number (two digits), the participant's number (three digits) and a letter code (three letters). The sponsor will ensure that each participant has provided written consent for access to their individual data, strictly limited to what is necessary for quality control of the research.

## Access to data

Participation in the protocol implies that investigators will make available the documents and personal data strictly necessary for the monitoring, quality control and auditing of the research to authorised individuals, in compliance with the applicable laws and regulations.

## Patient and public involvement

There was no patient or public involvement in the design, execution, reporting or dissemination plans of our study.

## Ethics and dissemination

This trial has received a favourable opinion from the Committee for the Protection of Persons, and authorisation from the French authorities (Comité de protection des personnes Nord Ouest, IDRCB: 2023-A02566-39). Protocol V.1.1 was approved on 22 January 2024. The trial is registered on ClinicalTrials.gov (NCT06425614). The findings will be disseminated through oral communications at national and international scientific meetings and peer-reviewed journal publications.

## Data Availability statement

Individual participant data will be made available on reasonable request to qualified researchers, following review and approval by the study sponsor and ethics committee.

## Author affiliations

**Contributors** All authors contributed to the design of the protocol, including its concept and the critical review and final approval of the manuscript. AB and AM contributed equally to this paper. AB, AM, AO and AB drafted the manuscript. AA, AC, VEB and CM contributed to the design of the laboratory processes. AB, AM, AF,

<footnote n="1">¹Department of Cardiovascular Anesthesia and Critical Care, CHU Bordeaux, Haut-Lévêque hospital, Bordeaux, France</footnote>

<footnote n="2">²INSERM, U1034, Biologie des maladies cardiovasculaires, Univ. Bordeaux, Pessac, France</footnote>

<footnote n="3">³Department of Anesthesia and Critical Care, Pontchaillou, Rennes University Hospital, Rennes, France</footnote>

<footnote n="4">⁴Service d'Information Médicale, Clinical Epidemiology Unit (USMR), CHU Bordeaux, Pôle de Santé Publique, Bordeaux, France</footnote>

<footnote n="5">⁵Department of Cardiology and Cardio-Vascular Surgery, CHU Bordeaux, Haut-Lévêque hospital, Bordeaux, France</footnote>

<footnote n="6">⁶Hematology Laboratory, Reference Center for Inherited Platelet Disorders, CHU Bordeaux, Bordeaux, France</footnote>

<footnote n="7">⁷Clinical Pharmacy of Medical Devices, CHU Bordeaux, Bordeaux, France</footnote>

<footnote n="8">⁸Clinical Research Manager, Internal Promotion. Clinical Research and Innovation Department, CHU Bordeaux, Bordeaux, France</footnote>
GR, AO, MP, AB, CB, GR and NN contributed to the design of participant. AB, AM, AO, AC, JI and GR contributed to the design of the health economic evaluation. AB is the guarantor.

**Funding** This interventional research was mostly supported by a grant from the French Ministry of Health (number PHRC-N 2021-0296). This research was also supported by i-SEP and Stago by providing machines and consumables free of charge. These two companies were neither involved in study conception, study conduct, data analysis and interpretation nor in the manuscript drafting.

**Competing interests** None declared.

**Patient and public involvement** Patients and/or the public were not involved in the design, conduct, reporting or dissemination plans of this research.

**Patient consent for publication** Not applicable.

**Provenance and peer review** Not commissioned; externally peer-reviewed.

**Supplemental material** This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

**Open access** This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

ORCID iD

Antoine Beurton http://orcid.org/0000-0002-3708-4653

REFERENCES

1 Dyke C, Aronson S, Dietrich W, et al. Universal definition of perioperative bleeding in adult cardiac surgery. *J Thorac Cardiovasc Surg* 2014;147:1458-63.

2 Robich MP, Koch CG, Johnston DR, et al. Trends in blood utilization in United States cardiac surgical patients. *Transfusion (Paris)* 2015;55:805-14.

3 Orlov D, McCluskey SA, Selby R, et al. Platelet dysfunction as measured by a point-of-care monitor is an independent predictor of high blood loss in cardiac surgery. *Anesth Analg* 2014;118:257-63.

4 Solomon C, Baryshnikova E, Tripodi A, et al. Fibrinogen measurement in cardiac surgery with cardiopulmonary bypass: analysis of repeatability and agreement of Clauss method within and between six different laboratories. *Thromb Haemost* 2014;112:109-17.

5 Kindo M, Hoang Minh T, Gerelli S, et al. Plasma fibrinogen level on admission to the intensive care unit is a powerful predictor of postoperative bleeding after cardiac surgery with cardiopulmonary bypass. *Thromb Res* 2014;134:360-8.

6 Levy JH, Faraoni D, Almond CS, et al. Consensus Statement: Hemostasis Trial Outcomes in Cardiac Surgery and Mechanical Support. *Ann Thorac Surg* 2022;113:1026-35.

7 Colson PH, Gaudard P, Fellahi J-L, et al. Active Bleeding after Cardiac Surgery: A Prospective Observational Multicenter Study. *PLoS One* 2016;11:e0162396.

8 Bartoszko J, Wijeysundera DN, Karkouti K, et al. Comparison of Two Major Perioperative Bleeding Scores for Cardiac Surgery Trials: Universal Definition of Perioperative Bleeding in Cardiac Surgery and European Coronary Artery Bypass Grafting Bleeding Severity Grade. *Anesthesiology* 2018;129:1092-100.

9 Mion S, Duval B, Besnard T, et al. U-shaped relationship between pre-operative plasma fibrinogen levels and severe peri-operative bleeding in cardiac surgery. *Eur J Anaesthesiol* 2020;37:889-97.

10 Karkouti K, Wijeysundera DN, Yau TM, et al. The independent association of massive blood loss with mortality in cardiac surgery. *Transfusion* 2004;44:1453-62.

11 Karthik S, Grayson AD, McCarron EE, et al. Reexploration for bleeding after coronary artery bypass surgery: risk factors, outcomes, and the effect of time delay. *Ann Thorac Surg* 2004;78:527-34.

12 Koch CG, Li L, Duncan AI, et al. Morbidity and mortality risk associated with red blood cell and blood-component transfusion in isolated coronary artery bypass grafting. *Crit Care Med* 2006;34:1608-16.

13 Horvath KA, Acker MA, Chang H, et al. Blood transfusion and infection after cardiac surgery. *Ann Thorac Surg* 2013;95:2194-201.

14 Raphael J, Mazer CD, Subramani S, et al. Society of Cardiovascular Anesthesiologists Clinical Practice Improvement Advisory for Management of Perioperative Bleeding and Hemostasis in Cardiac Surgery Patients. *Anesth Analg* 2019;129:1209-21.

15 Casselman FPA, Lance MD, Ahmed A, et al. 2024 EACTS/EACTAIC Guidelines on patient blood management in adult cardiac surgery in collaboration with EBCP. *Eur J Cardiothorac Surg* 2025;67.

16 Kelleher A, Davidson S, Gohil M, et al. A quality assurance programme for cell salvage in cardiac surgery. *Anaesthesia* 2011;66:901-6.

17 Adam EH, Funke M, Zacharowski K, et al. Impact of Intraoperative Cell Salvage on Blood Coagulation Factor Concentrations in Patients Undergoing Cardiac Surgery. *Anesth Analg* 2020;130:1389-95.

18 Mansour A, Decouture B, Roussel M, et al. Combined Platelet and Erythrocyte Salvage: Evaluation of a New Filtration-based Autotransfusion Device. *Anesthesiology* 2021;135:246-57.

19 Mansour A, Beurton A, Godier A, et al. Combined Platelet and Red Blood Cell Recovery during On-pump Cardiac Surgery Using same by i-SEP Autotransfusion Device: A First-in-human Noncomparative Study (i-TRANSEP Study). *Anesthesiology* 2023;139:287-97.

20 Alghamdi AA, Davis A, Brister S, et al. Development and validation of Transfusion Risk Understanding Scoring Tool (TRUST) to stratify cardiac surgery patients according to their blood transfusion needs. *Transfusion* 2006;46:1120-9.

21 Klein AA, Collier T, Yeates J, et al. The ACTA PORT-score for predicting perioperative risk of blood transfusion for adult cardiac surgery. *Br J Anaesth* 2017;119:394-401.

22 Ranucci M, Castelvecchio S, Frigola A, et al. Predicting transfusions in cardiac surgery: the easier, the better: the Transfusion Risk and Clinical Knowledge score. *Vox Sang* 2009;96:324-32.

23 Besnier E, Schmidely P, Dubois G, et al. POBS-Card, a new score of severe bleeding after cardiac surgery: Construction and external validation. *JTCVS Open* 2024;19:183-99.

24 Mehta RH, Sheng S, O'Brien SM, et al. Reoperation for Bleeding in Patients Undergoing Coronary Artery Bypass Surgery. *Circ: Cardiovascular Quality and Outcomes* 2009;2:583-90.

25 Fröjd V, Jeppsson A. Reexploration for Bleeding and Its Association With Mortality After Cardiac Surgery. *Ann Thorac Surg* 2016;102:109-17.

26 Paparella D, Whitlock R. Safety of Salvaged Blood and Risk of Coagulopathy in Cardiac Surgery. *Semin Thromb Hemost* 2016;42:166-71.

27 Engels GE, van Klarenbosch J, Gu YJ, et al. Intraoperative cell salvage during cardiac surgery is associated with reduced postoperative lung injury. *Interact Cardiovasc Thorac Surg* 2016;22:298-304.

28 Gäbel J, Westerberg M, Bengtsson A, et al. Cell salvage of cardiotomy suction blood improves the balance between pro- and anti-inflammatory cytokines after cardiac surgery. *Eur J Cardiothorac Surg* 2013;44:506-11.

29 de Haan J, Boonstra PW, Monnink SH, et al. Retransfusion of suctioned blood during cardiopulmonary bypass impairs hemostasis. *Ann Thorac Surg* 1995;59:901-7.

30 Wahba A, Kunst G, De Somer F, et al. 2024 EACTS/EACTAIC/EBCP Guidelines on cardiopulmonary bypass in adult cardiac surgery. *Eur J Cardiothorac Surg* 2025;67:ezae354.