Detection of elevated INR by thromboelastometry and thromboelastography in warfarin treated patients and healthy controls

Schmidt, David E.; Holmström, Margareta; Majeed, Ammar; Doris, Naslin; Wallén, Håkan; Ågren, Anna

doi:10.1016/j.thromres.2015.02.022

Cited by 64 publications

(36 citation statements)

References 16 publications

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“…[19] This contrasts with what is observed in non-cirrhotic patients treated with warfarin, wherein a good correlation between CT-EXTEM and PT-INR is reported. [31] …”

Section: Discussionmentioning

confidence: 99%

Thromboelastometry

et al. 2017

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“…[19] This contrasts with what is observed in non-cirrhotic patients treated with warfarin, wherein a good correlation between CT-EXTEM and PT-INR is reported. [31] …”

Section: Discussionmentioning

confidence: 99%

Thromboelastometry

et al. 2017

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“…Similar to LSR and TEG, the aPTT assay uses kaolin or celite to activate clot formation via the intrinsic and common pathway, whereas PT/INR employs tissue factor utilizing extrinsic and common pathway catalysers for coagulation [36,37]. In other words, LSR, aPTT and TEG assays are more sensitive to coagulation cascades resulting from kaolin activation via the intrinsic and common pathways, explaining the high correlation between LSR clotting time and aPTT compared to PT/INR (Fig 2C and 2F) [38]. Although kaolin activation was employed in this study to evaluate warfarin therapy using LSR, the use of tissue factor as a clotting activator could just as easily be employed in conjunction with LSR to allow for a more accurate evaluation of PT/INR values.…”

Section: Discussionmentioning

confidence: 99%

Optical sensing of anticoagulation status: Towards point-of-care coagulation testing

et al. 2017

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Anticoagulant overdose is associated with major bleeding complications. Rapid coagulation sensing may ensure safe and accurate anticoagulant dosing and reduce bleeding risk. Here, we report the novel use of Laser Speckle Rheology (LSR) for measuring anticoagulation and haemodilution status in whole blood. In the LSR approach, blood from 12 patients and 4 swine was placed in disposable cartridges and time-varying intensity fluctuations of laser speckle patterns were measured to quantify the viscoelastic modulus during clotting. Coagulation parameters, mainly clotting time, clot progression rate (α-angle) and maximum clot stiffness (MA) were derived from the clot viscoelasticity trace and compared with standard Thromboelastography (TEG). To demonstrate the capability for anticoagulation sensing in patients, blood samples from 12 patients treated with warfarin anticoagulant were analyzed. LSR clotting time correlated with prothrombin and activated partial thromboplastin time (r = 0.57–0.77, p<0.04) and all LSR parameters demonstrated good correlation with TEG (r = 0.61–0.87, p<0.04). To further evaluate the dose-dependent sensitivity of LSR parameters, swine blood was spiked with varying concentrations of heparin, argatroban and rivaroxaban or serially diluted with saline. We observed that anticoagulant treatments prolonged LSR clotting time in a dose-dependent manner that correlated closely with TEG (r = 0.99, p<0.01). LSR angle was unaltered by anticoagulation whereas TEG angle presented dose-dependent diminution likely linked to the mechanical manipulation of the clot. In both LSR and TEG, MA was largely unaffected by anticoagulation, and LSR presented a higher sensitivity to increased haemodilution in comparison to TEG (p<0.01). Our results establish that LSR rapidly and accurately measures the response of various anticoagulants, opening the opportunity for routine anticoagulation monitoring at the point-of-care or for patient self-testing.

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“…The INR is the gold standard for monitoring patients treated with vitamin K antagonists. Patients on warfarin can be identified with EXTEM while the RapidTEG ® and K‐TEG ® showed inadequate sensitivity and specificity (Dunham et al , ; Schmidt et al , ). While these assays may be helpful in guiding haemostatic therapy during trauma and surgery, they are not validated for warfarin dosing or reversal.…”

Section: Application Of the Viscoelastic Assaysmentioning

confidence: 99%

The place of viscoelastic testing in clinical practice

Hans

Besser

2016

Br J Haematol

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Hellmut Hartert was the first person to exploit the viscoelastic properties of clotting blood to measure blood coagulation in 1948. Since then, the technology has improved, allowing these analyses to be performed as point-of-care tests with immediately-available results. The addition of several activators and inhibitors to the original assay creates a panel of tests able to quantify the different aspects of blood clotting that can rival conventional laboratory assays. However, although much progress has been made, the standardization and validation of these tests still need improvement. Viscoelastic analyses of blood coagulation are mainly used to guide haemostatic therapy in bleeding patients and have proven superior to standard clotting tests in some circumstances. There is potential to extend their use to other areas, such as drug monitoring, and diagnosis and management of congenital bleeding disorders. The forthcoming cartridge-based assays are expected to improve the reliability and usability of viscoelastic assays of blood coagulation but high quality clinical trials remain urgently needed to determine their exact place, benefit and cost effectiveness.

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Detection of elevated INR by thromboelastometry and thromboelastography in warfarin treated patients and healthy controls

Cited by 64 publications

References 16 publications

Thromboelastometry

Thromboelastometry

Optical sensing of anticoagulation status: Towards point-of-care coagulation testing

The place of viscoelastic testing in clinical practice

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