Point-of-Care Measurement of Activated Clotting Time for Cardiac Surgery as measured by the Hemochron Signature Eliteand the Abbott i-STAT: Agreement, Concordance, and Clinical Reliability

10.21203/rs.2.199/v3 ◽

2019 ◽

Author(s):

Daniel Dirkmann ◽

Elisabeth Nagy ◽

Martin Walter Britten ◽

Juergen Peters

Keyword(s):

Cardiac Surgery ◽

Linear Correlation ◽

Point Of Care ◽

Clotting Time ◽

Cohen’S Kappa ◽

Cohen's Kappa ◽

Activated Clotting Time ◽

Target Values ◽

Heparin Anticoagulation ◽

Parallel Measurements

Abstract Background: Since inadequate heparin anticoagulation and insufficient reversal can result in complications during cardiopulmonary bypass (CPB) surgery, heparin anticoagulation monitoring by point-of-care (POC) activated clotting time (ACT) measurements is essential for CPB initiation, maintainance, and anticoagulant reversal. However, concerns exist regarding reproducibility of ACT assays and comparability of devices. Methods: We evaluated the agreement of ACT assays using four parallel measurements performed on two commonly used devices each (i.e., two Hemochron Signature Elite (Hemochron) and two Abbott i-STAT (i-STAT) devices, respectively). Blood samples from 30 patients undergoing cardiac surgery on CPB were assayed at specified steps (baseline, after heparin administration, after protamine administration) with four parallel measurements (two of each device type) using commercial Kaolin activated assays provided by the respective manufactures. Measurements were compared between identical and different device types using linear regression, Bland-Altman analyses, and calculation of Cohen’s kappa coefficient. Results: Parallel i-STAT ACTs demonstrated a good linear correlation (r=0.985). Bias, as determined by Bland-Altman analysis, was low (-3.8s; 95% limits of agreement (LOA): -77.8 -70.2s), and Cohen’s Kappa demonstrated good agreement (kappa=0.809). Hemochron derived ACTs demonstrated worse linear correlation (r=0.782), larger bias with considerably broader LOA (-13.14s; 95%LOA:-316.3-290s), and lesser concordance between parallel assays (kappa=0.554). Although demonstrating a fair linear correlation (r=0.815), parallel measurements on different ACT-devices showed large bias (-20s; 95% LOA: -290-250s) and little concordance (kappa=0.368). Overall, disconcordant results according to clinically predefined target values were more frequent with the Hemochron than i-STAT. Furthermore, while discrepancies in ACT between two parallel iSTAT assays showed little or no clinical relevance, deviations from parallel Hemochron assays and iSTAT versus Hemochron measurements revealed marked and sometimes clinically critical deviations. Conclusion: Currently used ACT point-of-care devices cannot be used interchangeably. Furthermore, our data question the reliability of the Hemochron in assessing adequacy of heparin anticoagulation monitoring for CPB.

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Point-of-Care Measurement of Activated Clotting Time for Cardiac Surgery as measured by the Hemochron Signature Eliteand the Abbott i-STAT: Agreement, Concordance, and Clinical Reliability

10.21203/rs.2.199/v1 ◽

2019 ◽

Author(s):

Daniel Dirkmann ◽

Elisabeth Nagy ◽

Martin Walter Britten ◽

Juergen Peters

Keyword(s):

Cardiac Surgery ◽

Cardiopulmonary Bypass ◽

Linear Correlation ◽

Point Of Care ◽

Clotting Time ◽

Cohen’S Kappa ◽

Cohen's Kappa ◽

Activated Clotting Time ◽

Heparin Anticoagulation ◽

Parallel Measurements

Abstract Background: Since inadequate heparin anticoagulation and insufficient reversal can result in complications during cardiopulmonary bypass (CPB) surgery, heparin anticoagulation monitoring by point-of-care (POC) activated clotting time (ACT) measurements is essential for CPB initiation, maintainance, and anticoagulant reversal. However, concerns exist regarding reproducibility of ACT assays and comparability of devices. Methods: We evaluated the agreement of ACT assays using four parallel measurements performed on two commonly used devices each (i.e., two Hemochron Signature Elite (Hemochron) and two Abbott i-STAT (i-STAT) devices, respectively). Blood samples from 30 patients undergoing cardiac surgery on CPB were assayed at specified steps (baseline, after heparin administration, after protamine administration) with four parallel measurements (two of each device type) using commercial Kaolin activated assays provided by the respective manufactures. Measurements were compared between identical and different device types using linear regression, Bland-Altman analyses, and calculation of Cohen’s kappa coefficient. Results: Parallel i-STAT ACTs demonstrated a good linear correlation (r=0.985). Bias, as determined by Bland-Altman analysis, was low (-3.8s; 95% limits of agreement (LOA): -77.8 -70.2s), and Cohen’s Kappa demonstrated good agreement (kappa=0.809). Hemochron derived ACTs demonstrated worse linear correlation (r=0.782), larger bias with considerably broader LOA (-13.14s; 95%LOA:-316.3-290s), and lesser concordance between parallel assays (kappa=0.554). Although demonstrating a fair linear correlation (r=0.815), parallel measurements on different ACT-devices showed large bias (-20s; 95% LOA: -290-250s) and little concordance (kappa=0.368). Overall, disconcordant results according to clinically predefined target values were more frequent with the Hemochron than i-STAT. Furthermore, while discrepancies in ACT between two parallel iSTAT assays showed little or no clinical relevance, deviations from parallel Hemochron assays and iSTAT versus Hemochron measurements revealed marked and sometimes clinically critical deviations. Conclusion: Currently used ACT point-of-care devices cannot be used interchangeably. Furthermore, our data question the reliability of the Hemochron in assessing adequacy of heparin anticoagulation monitoring for CPB. Keywords: Activated clotting time, ACT, method comparison, anticoagulation, cardiopulmonary bypass, heparin, protamine

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A comparative analysis of four activated clotting time measurement devices in cardiac surgery with cardiopulmonary bypass

Perfusion ◽

10.1177/0267659120949351 ◽

2020 ◽

pp. 026765912094935

Author(s):

Han Li ◽

Cyril Serrick ◽

Vivek Rao ◽

Paul M Yip

Keyword(s):

Cardiac Surgery ◽

Cardiopulmonary Bypass ◽

System Analysis ◽

Point Of Care ◽

Measurement Range ◽

Medical Decision ◽

Clotting Time ◽

Activated Clotting Time ◽

Decision Points ◽

Heparin Anticoagulation

Background: In cardiac surgery on cardiopulmonary bypass (CPB), heparin anticoagulation is monitored by point-of-care measurement of activated clotting time (ACT). The objective of this study was to compare four ACT systems in cardiac surgery in terms of their reproducibility, agreement and potential clinical impact at relevant medical decision points. Methods: The study included 40 cardiac surgery patients. Samples were taken at five time points before (T1), after heparinization for CPB (T2, T3, T4), and after heparin reversal (T5). The reproducibility, correlation, and differences in ACT values were assessed with two devices from each of the four ACT systems: Instrumentation Laboratory Hemochron Elite (Hmch), Medtronic HMS Plus (HMS), Abbott i-STAT, and Helena Abrazo. Subrange analyses were performed for low ACT values (results from T1, T5) and high ACT values (results from T2, T3, T4). Results: Within-system analysis showed strong linear correlation between paired measurements (R = 0.968-0.993). However, Hmch showed poorer reproducibility with highest proportion of values that exceed a difference of 10% and highest overall standard error of 74 seconds across the measurement range compared to that of the others (range 39-47 seconds, respectively). For inter-system comparison, using Hmch as reference, ACTs were strongly correlated as follows: HMS (R = 0.938), i-STAT (R = 0.911), and Abrazo (R = 0.911). Agreement analysis in the high ACT range showed HMS tended to have higher ACT values with +11% bias over Hmch, whereas i-STAT (–8% bias) and Abrazo (–13% bias) tended to underestimate. Post-protamine ACT results were dependent on device type where Hmch yielded highest post-protamine ACT (+13% higher than baseline) compared to –16% for HMS, –10% for iSTAT and 0% for Abrazo. Conclusions: Each device had individual reproducibility and biases, which may impact peri-operative heparin management. Careful validation must be undertaken when adopting a different method as decision limits would be affected. Clinicians should also be cautious using ACT as the only indicator for full heparin reversal.

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Point-of-care measurement of activated clotting time for cardiac surgery as measured by the Hemochron signature elite and the Abbott i-STAT: agreement, concordance, and clinical reliability

BMC Anesthesiology ◽

10.1186/s12871-019-0846-z ◽

2019 ◽

Vol 19 (1) ◽

Cited By ~ 3

Author(s):

Daniel Dirkmann ◽

Elisabeth Nagy ◽

Martin W. Britten ◽

Jürgen Peters

Keyword(s):

Cardiac Surgery ◽

Point Of Care ◽

Clotting Time ◽

Activated Clotting Time

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Evaluation of a New Sonoclot Device for Heparin Management in Cardiac Surgery

Clinical and Applied Thrombosis/Hemostasis ◽

10.1177/1076029616651148 ◽

2016 ◽

Vol 23 (1) ◽

pp. 20-26 ◽

Cited By ~ 3

Author(s):

Omer Dzemali ◽

Michael T. Ganter ◽

Alicja Zientara ◽

Kirk Graves ◽

Renate Behr ◽

...

Keyword(s):

Cardiac Surgery ◽

Glass Bead ◽

Percentage Error ◽

Altman Analysis ◽

Clotting Time ◽

Bland Altman Analysis ◽

New Device ◽

Activated Clotting Time ◽

Heparin Administration ◽

Target Values

Background: Sonoclot is used to measure kaolin-based activated clotting time (kACT) for heparin management. Apart from measuring kACT, the device assesses the patient’s coagulation status by glass bead–activated tests (gbACTs; measuring also clot rate [CR] and platelet function [PF]). Recently, a new version of the Sonoclot has been released, and the redesign may result in performance changes. The aim of this study was to evaluate and compare the performance of the new (S2) and the previous (S1) Sonoclot. Methods: The S1 was used in the routine management of 30 patients undergoing elective cardiac surgery. Blood samples were taken at baseline (T1), after heparin administration (200 U/kg, 100 U/kg; T2 and T3), during cardiopulmonary bypass (T4), after protamine infusion (T5), and before intensive care unit transfer (T6). Kaolin-based activated clotting time and gbACTs were measured in duplicate by both the old and the new device and performance compared by Bland-Altman analysis and percentage error calculation. Results: A total of 300 kACT and 180 gbACTs were available. Bland-Altman analysis for kACT revealed that S2 consistently reported results in shorter time compared to S1 (overall = −14.7%). Comparing S2 and S1, the glass bead–activated tests showed mean percentage differences of −18.9% (gbACTs), +37.4% (CR), and −3.7% (PF). Conclusion: Since clotting is faster in the new S2 compared to S1, shorter clotting times have to be considered in clinical practice. The use of S2 kACT in heparin management will result in higher heparin and protamine dosing unless heparin kACT target values are adjusted to correct for the differences in results between S1 and S2.

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Variability of three activated clotting time point-of-care systems in cardiac surgery: reinforcing available evidence

Perfusion ◽

10.1177/02676591211023687 ◽

2021 ◽

pp. 026765912110236

Author(s):

Diego Solís Clavijo ◽

Abel Ortega Cotano ◽

Nuria Alonso Peña ◽

Sergio Caballero Gálvez ◽

Fernando Arellano Núñez ◽

...

Keyword(s):

Cardiac Surgery ◽

Point Of Care ◽

Clotting Time ◽

Mean Values ◽

Activated Clotting Time ◽

Bland Altman Method ◽

Anticoagulant Drugs ◽

Care Systems ◽

Point Of Care Systems ◽

The Mean

Background: Cardiac surgery with extracorporeal circulation (ECC) requires the administration of anticoagulant drugs to maintain ACT ranges 400–600 seconds, which requires exhaustive coagulation monitoring for which various point-of-care devices are available. However, there is variability between them, so we aimed to compare the values in ACT measurement. Methods: Simultaneous ACT measurements were performed with the Hemochron Response®, Hemostasis Management System Plus® (HMS Plus®) and Hemochron Signature® systems. Results: A total of 255 simultaneous measurements were taken, the mean and standard deviation (SD) of each device were: Hemochron Signature® 361.1 seconds (SD: 156.9), HMS Plus® 412.8 seconds (SD: 180.9) and Hemochron Response® 422.8 seconds (SD: 187.9), being these differences statistically significant (Fridman’s test p < 0.01). For comparisons the Bland–Altman method was used, resulting the Hemochron Response® has 61.7 seconds higher mean values than the Hemochron Signature®, the Hemochron Response® 10 seconds higher than the HMS Plus® and the HMS Plus® 51.7 seconds higher than the Hemochron Signature®. Conclusion: The differences found in comparisons are considered to be clinically relevant, which is why it is considered important to make the variability of the different monitoring systems known and to take them into account for optimal control of this parameter and its clinical repercussions.

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