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Monitoring activated clotting time for combined heparin and aprotinin application: in vivo evaluation of a new aprotinin-insensitive test using Sonoclot


Ganter, M; Monn, A; Tavakoli, R; Genoni, M; Klaghofer, R; Furrer, L; Honegger, H; Hofer, C (2006). Monitoring activated clotting time for combined heparin and aprotinin application: in vivo evaluation of a new aprotinin-insensitive test using Sonoclot. European Journal of Cardio-Thoracic Surgery, 30(2):278-284.

Abstract

Objective: Kaolin-based activated clotting time assessed by HEMOCHRON (HkACT) is a clinical standard for heparin monitoring alone and combined with aprotinin during cardiopulmonary bypass (CPB). However, aprotinin is known to prolong not only celite-based but also kaolin-based activated clotting time. Overestimation of activated clotting times implies a potential hazardous risk of subtherapeutic heparin anticoagulation. Recently, a novel ‘aprotinin-insensitive' activated clotting time test has been developed for the SONOCLOT analyzer (SaiACT). The aim of our study was to evaluate SaiACT in patients undergoing CPB in presence of heparin and aprotinin. Methods: Blood samples were taken from 44 elective cardiac surgery patients at the following measurement time points: baseline (T0); before CPB after heparinization (T1 and T2); on CPB, before administration of aprotinin (T3); 15, 30, and 60min on CPB after administration of aprotinin (T4, T5, and T6); after protamine infusion (T7). On each measurement time point, activated clotting time was assessed with HkACT and SaiACT, both in duplicate. Furthermore, the rate of factor Xa inhibition and antithrombin concentration were measured. Statistical analysis was done using Bland and Altman analysis, Pearson's correlation, and ANOVA with post hoc Bonferroni-Dunn correction. Results: Monitoring anticoagulation with SaiACT showed reliable readings. Compared to the established HkACT, SaiACT values were lower at all measurement time points. On CPB but before administration of aprotinin (T3), SaiACT values (mean±SD) were 44±118s lower compared to HkACT. However, the difference between the two measurement techniques increased significantly on CPB after aprotinin administration (T4-T6; 89±152s, P=0.032). Correlation of ACT measurements with anti-Xa activity was unchanged for SaiACT before and after aprotinin administration (r2=0.473 and 0.487, respectively; P=0.794), but was lower for HkACT after aprotinin administration (r2=0.481 and 0.361, respectively; P=0.041). On CPB after administration of aprotinin, 96% of all ACT values were classified as therapeutic by HkACT, but only 86% of all values were classified therapeutic if ACT was determined by SaiACT. Test variability was comparable for SaiACT and HkACT. Conclusions: The use of SaiACT may result in more consistent heparin management that is less affected by aprotinin and a corresponding increase in heparin administration for patients receiving aprotinin

Abstract

Objective: Kaolin-based activated clotting time assessed by HEMOCHRON (HkACT) is a clinical standard for heparin monitoring alone and combined with aprotinin during cardiopulmonary bypass (CPB). However, aprotinin is known to prolong not only celite-based but also kaolin-based activated clotting time. Overestimation of activated clotting times implies a potential hazardous risk of subtherapeutic heparin anticoagulation. Recently, a novel ‘aprotinin-insensitive' activated clotting time test has been developed for the SONOCLOT analyzer (SaiACT). The aim of our study was to evaluate SaiACT in patients undergoing CPB in presence of heparin and aprotinin. Methods: Blood samples were taken from 44 elective cardiac surgery patients at the following measurement time points: baseline (T0); before CPB after heparinization (T1 and T2); on CPB, before administration of aprotinin (T3); 15, 30, and 60min on CPB after administration of aprotinin (T4, T5, and T6); after protamine infusion (T7). On each measurement time point, activated clotting time was assessed with HkACT and SaiACT, both in duplicate. Furthermore, the rate of factor Xa inhibition and antithrombin concentration were measured. Statistical analysis was done using Bland and Altman analysis, Pearson's correlation, and ANOVA with post hoc Bonferroni-Dunn correction. Results: Monitoring anticoagulation with SaiACT showed reliable readings. Compared to the established HkACT, SaiACT values were lower at all measurement time points. On CPB but before administration of aprotinin (T3), SaiACT values (mean±SD) were 44±118s lower compared to HkACT. However, the difference between the two measurement techniques increased significantly on CPB after aprotinin administration (T4-T6; 89±152s, P=0.032). Correlation of ACT measurements with anti-Xa activity was unchanged for SaiACT before and after aprotinin administration (r2=0.473 and 0.487, respectively; P=0.794), but was lower for HkACT after aprotinin administration (r2=0.481 and 0.361, respectively; P=0.041). On CPB after administration of aprotinin, 96% of all ACT values were classified as therapeutic by HkACT, but only 86% of all values were classified therapeutic if ACT was determined by SaiACT. Test variability was comparable for SaiACT and HkACT. Conclusions: The use of SaiACT may result in more consistent heparin management that is less affected by aprotinin and a corresponding increase in heparin administration for patients receiving aprotinin

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Item Type:Journal Article, refereed, original work
Communities & Collections:National licences > 142-005
Dewey Decimal Classification:610 Medicine & health
Language:English
Date:1 August 2006
Deposited On:02 Nov 2018 06:47
Last Modified:24 Sep 2019 23:41
Publisher:Oxford University Press
ISSN:1010-7940
OA Status:Green
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1016/j.ejcts.2006.05.016
Related URLs:https://www.swissbib.ch/Search/Results?lookfor=nationallicenceoxford101016jejcts200605016 (Library Catalogue)

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