Identification of clinical factors predicting warfarin sensitivity after cardiac surgery

Karen Tyson, Nevil Hutchinson, Sian Williams, Greg Scutt

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Objectives: Warfarin is commonly initiated post-cardiac surgery to reduce the risk of intra-cardiac thrombus formation.Studies have found that sensitivity is increased after cardiac surgery and anti-coagulation is subsequently difficult to manage.This study set out to identify clinical markers of increased warfarin sensitivity in patients’post-cardiac surgery, and build a modelthat can predict warfarin sensitivity, and improve safety in this setting.Methods:The study was an observational, retrospective cohort design.Clinical parameters including Left Ventricular Ejection Fraction (LVEF), cross-clamp time, age, serum albumin and C-reactive protein concentrations were collected from consenting patients who had undergone cardiac surgery and prescribed post-operative warfarin. Warfarin Dose Index (WDI) was calculated for each patient from their INR and warfarin dose, as a measure of sensitivity.Results:41 patients were recruited to the study.Logarithmically transformed WDI (log WDI) significantly correlated with LVEF, cardiopulmonary bypass (CPB) time, cross-clamp time, baseline INR and co-administration of amiodarone (p<0.05).When added to a linear regression model, LVEF and cross-clamp time produced a model that accounted for 41% of variance in log WDI (R2=0.41), p=0.0002).Applying a log WDI cut-off value of -0.349 discriminated between patients who develop an INR >4 and those who do not with a sensitivity of 75% and a specificity of 70%.Conclusions:This single centrestudy has highlighted two risk factors for increased warfarin sensitivity post-cardiac surgery.Further research is needed to confirm these findings in a wider, more diverse population, and to validate this model.
Original languageEnglish
JournalTherapeutic Advances in Drug Safety
DOIs
Publication statusPublished - 5 Jun 2018

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Warfarin
Thoracic Surgery
International Normalized Ratio
Stroke Volume
Amiodarone
Cardiopulmonary Bypass
Serum Albumin
C-Reactive Protein
Observational Studies
Thrombosis
Biomarkers
Warfarin Sensitivity
Safety
Research
Population

Bibliographical note

Karen Tyson, Nevil Hutchinson, Sian Williams & Greg Scutt, Identification of clinical factors predicting warfarin sensitivity 14 after cardiac surgery, Therapeutic Advances in Drug Safety. Copyright © 2018 © The Author(s). Reprinted by permission of SAGE Publications.

Cite this

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title = "Identification of clinical factors predicting warfarin sensitivity after cardiac surgery",
abstract = "Objectives: Warfarin is commonly initiated post-cardiac surgery to reduce the risk of intra-cardiac thrombus formation.Studies have found that sensitivity is increased after cardiac surgery and anti-coagulation is subsequently difficult to manage.This study set out to identify clinical markers of increased warfarin sensitivity in patients’post-cardiac surgery, and build a modelthat can predict warfarin sensitivity, and improve safety in this setting.Methods:The study was an observational, retrospective cohort design.Clinical parameters including Left Ventricular Ejection Fraction (LVEF), cross-clamp time, age, serum albumin and C-reactive protein concentrations were collected from consenting patients who had undergone cardiac surgery and prescribed post-operative warfarin. Warfarin Dose Index (WDI) was calculated for each patient from their INR and warfarin dose, as a measure of sensitivity.Results:41 patients were recruited to the study.Logarithmically transformed WDI (log WDI) significantly correlated with LVEF, cardiopulmonary bypass (CPB) time, cross-clamp time, baseline INR and co-administration of amiodarone (p<0.05).When added to a linear regression model, LVEF and cross-clamp time produced a model that accounted for 41{\%} of variance in log WDI (R2=0.41), p=0.0002).Applying a log WDI cut-off value of -0.349 discriminated between patients who develop an INR >4 and those who do not with a sensitivity of 75{\%} and a specificity of 70{\%}.Conclusions:This single centrestudy has highlighted two risk factors for increased warfarin sensitivity post-cardiac surgery.Further research is needed to confirm these findings in a wider, more diverse population, and to validate this model.",
author = "Karen Tyson and Nevil Hutchinson and Sian Williams and Greg Scutt",
note = "Karen Tyson, Nevil Hutchinson, Sian Williams & Greg Scutt, Identification of clinical factors predicting warfarin sensitivity 14 after cardiac surgery, Therapeutic Advances in Drug Safety. Copyright {\circledC} 2018 {\circledC} The Author(s). Reprinted by permission of SAGE Publications.",
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doi = "10.1177/2042098618776541",
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Identification of clinical factors predicting warfarin sensitivity after cardiac surgery. / Tyson, Karen; Hutchinson, Nevil; Williams, Sian; Scutt, Greg.

In: Therapeutic Advances in Drug Safety, 05.06.2018.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Identification of clinical factors predicting warfarin sensitivity after cardiac surgery

AU - Tyson, Karen

AU - Hutchinson, Nevil

AU - Williams, Sian

AU - Scutt, Greg

N1 - Karen Tyson, Nevil Hutchinson, Sian Williams & Greg Scutt, Identification of clinical factors predicting warfarin sensitivity 14 after cardiac surgery, Therapeutic Advances in Drug Safety. Copyright © 2018 © The Author(s). Reprinted by permission of SAGE Publications.

PY - 2018/6/5

Y1 - 2018/6/5

N2 - Objectives: Warfarin is commonly initiated post-cardiac surgery to reduce the risk of intra-cardiac thrombus formation.Studies have found that sensitivity is increased after cardiac surgery and anti-coagulation is subsequently difficult to manage.This study set out to identify clinical markers of increased warfarin sensitivity in patients’post-cardiac surgery, and build a modelthat can predict warfarin sensitivity, and improve safety in this setting.Methods:The study was an observational, retrospective cohort design.Clinical parameters including Left Ventricular Ejection Fraction (LVEF), cross-clamp time, age, serum albumin and C-reactive protein concentrations were collected from consenting patients who had undergone cardiac surgery and prescribed post-operative warfarin. Warfarin Dose Index (WDI) was calculated for each patient from their INR and warfarin dose, as a measure of sensitivity.Results:41 patients were recruited to the study.Logarithmically transformed WDI (log WDI) significantly correlated with LVEF, cardiopulmonary bypass (CPB) time, cross-clamp time, baseline INR and co-administration of amiodarone (p<0.05).When added to a linear regression model, LVEF and cross-clamp time produced a model that accounted for 41% of variance in log WDI (R2=0.41), p=0.0002).Applying a log WDI cut-off value of -0.349 discriminated between patients who develop an INR >4 and those who do not with a sensitivity of 75% and a specificity of 70%.Conclusions:This single centrestudy has highlighted two risk factors for increased warfarin sensitivity post-cardiac surgery.Further research is needed to confirm these findings in a wider, more diverse population, and to validate this model.

AB - Objectives: Warfarin is commonly initiated post-cardiac surgery to reduce the risk of intra-cardiac thrombus formation.Studies have found that sensitivity is increased after cardiac surgery and anti-coagulation is subsequently difficult to manage.This study set out to identify clinical markers of increased warfarin sensitivity in patients’post-cardiac surgery, and build a modelthat can predict warfarin sensitivity, and improve safety in this setting.Methods:The study was an observational, retrospective cohort design.Clinical parameters including Left Ventricular Ejection Fraction (LVEF), cross-clamp time, age, serum albumin and C-reactive protein concentrations were collected from consenting patients who had undergone cardiac surgery and prescribed post-operative warfarin. Warfarin Dose Index (WDI) was calculated for each patient from their INR and warfarin dose, as a measure of sensitivity.Results:41 patients were recruited to the study.Logarithmically transformed WDI (log WDI) significantly correlated with LVEF, cardiopulmonary bypass (CPB) time, cross-clamp time, baseline INR and co-administration of amiodarone (p<0.05).When added to a linear regression model, LVEF and cross-clamp time produced a model that accounted for 41% of variance in log WDI (R2=0.41), p=0.0002).Applying a log WDI cut-off value of -0.349 discriminated between patients who develop an INR >4 and those who do not with a sensitivity of 75% and a specificity of 70%.Conclusions:This single centrestudy has highlighted two risk factors for increased warfarin sensitivity post-cardiac surgery.Further research is needed to confirm these findings in a wider, more diverse population, and to validate this model.

U2 - 10.1177/2042098618776541

DO - 10.1177/2042098618776541

M3 - Article

JO - Therapeutic Advances in Drug Safety

JF - Therapeutic Advances in Drug Safety

SN - 2042-0986

ER -