Anti-Factor Xa and Activated Partial Thromboplastin Time Measurements for Heparin Monitoring in Mechanical Circulatory Support

Sirtaz N Adatya, Nir Uriel, Hirad Yarmohammadi, Christopher T. Holley, Amy Feng, Samit S Roy, Mark T Reding, Ranjit John, Peter M Eckman, Nicole D Zantek

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

Objectives: This study investigated the relationship between anti-factor Xa (anti-FXa) and activated partial thromboplastin time (aPTT) for monitoring intravenous unfractionated heparin (IV-UFH) in patients with continuous-flow left ventricular assist devices (CF-LVADs). Background: CF-LVADs have become mainstream therapy for patients with advanced heart failure. Thromboembolic events, device thrombosis, and bleeding continue to be a challenge with this technology. Adequate anticoagulation is required to prevent these adverse events. Methods: A prospective study of consecutive patients implanted with a CF-LVAD was conducted. Paired samples were considered concordant if aPTT values fell into expected ranges for subtherapeutic, therapeutic, and supratherapeutic anti-FXa levels. Heparin dosing was on the basis of anti-Xa levels. Results: A total of 340 paired values from 38 patients were evaluated. Anti-FXa and aPTT were discordant in 253samples (74.4%), with a high degree of variability in aPTT for any given anti-FXa level (r2= 0.57). Results were discordant in 104 samples (63.8%) from patients undergoing bridging therapy with warfarin and in 149 samples (84.2%) from patients with device obstruction and/or hemolysis (p< 0.001). The most common pattern of discordance was a supratherapeutic aPTT value despite a therapeutic anti-FXa level (49.1% for bridging vs. 75.8% for device obstruction and/or hemolysis; p< 0.001). Conclusions: Levels of aPTT were disproportionately prolonged relative to the corresponding anti-FXa levels in CF-LVAD patients, particularly those with device obstruction. Hemolysis and warfarin administration may falsely elevate aPTT, resulting in overestimation of heparin concentration and under-anticoagulation. Use of aPTT and anti-FXa to guide heparin therapy may lead to different estimates of heparin concentration in the same patient.

Original languageEnglish (US)
Pages (from-to)314-322
Number of pages9
JournalJACC: Heart Failure
Volume3
Issue number4
DOIs
StatePublished - Apr 1 2015

Fingerprint

Factor Xa
Partial Thromboplastin Time
Heparin
Heart-Assist Devices
Hemolysis
Equipment and Supplies
Warfarin
Therapeutics
Thrombosis
Heart Failure
Prospective Studies
Hemorrhage
Technology

Keywords

  • APTT
  • Activated partial thromboplastin time
  • Anti-FXa
  • Anti-factor Xa
  • CF-LVAD
  • Continuous-flow left ventricular assist device
  • INR
  • IV-UFH
  • Intravenous unfractionated heparin
  • LDH
  • Monitoring

Cite this

Anti-Factor Xa and Activated Partial Thromboplastin Time Measurements for Heparin Monitoring in Mechanical Circulatory Support. / Adatya, Sirtaz N; Uriel, Nir; Yarmohammadi, Hirad; Holley, Christopher T.; Feng, Amy; Roy, Samit S; Reding, Mark T; John, Ranjit; Eckman, Peter M; Zantek, Nicole D.

In: JACC: Heart Failure, Vol. 3, No. 4, 01.04.2015, p. 314-322.

Research output: Contribution to journalArticle

Adatya, Sirtaz N ; Uriel, Nir ; Yarmohammadi, Hirad ; Holley, Christopher T. ; Feng, Amy ; Roy, Samit S ; Reding, Mark T ; John, Ranjit ; Eckman, Peter M ; Zantek, Nicole D. / Anti-Factor Xa and Activated Partial Thromboplastin Time Measurements for Heparin Monitoring in Mechanical Circulatory Support. In: JACC: Heart Failure. 2015 ; Vol. 3, No. 4. pp. 314-322.
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AU - Adatya, Sirtaz N

AU - Uriel, Nir

AU - Yarmohammadi, Hirad

AU - Holley, Christopher T.

AU - Feng, Amy

AU - Roy, Samit S

AU - Reding, Mark T

AU - John, Ranjit

AU - Eckman, Peter M

AU - Zantek, Nicole D

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N2 - Objectives: This study investigated the relationship between anti-factor Xa (anti-FXa) and activated partial thromboplastin time (aPTT) for monitoring intravenous unfractionated heparin (IV-UFH) in patients with continuous-flow left ventricular assist devices (CF-LVADs). Background: CF-LVADs have become mainstream therapy for patients with advanced heart failure. Thromboembolic events, device thrombosis, and bleeding continue to be a challenge with this technology. Adequate anticoagulation is required to prevent these adverse events. Methods: A prospective study of consecutive patients implanted with a CF-LVAD was conducted. Paired samples were considered concordant if aPTT values fell into expected ranges for subtherapeutic, therapeutic, and supratherapeutic anti-FXa levels. Heparin dosing was on the basis of anti-Xa levels. Results: A total of 340 paired values from 38 patients were evaluated. Anti-FXa and aPTT were discordant in 253samples (74.4%), with a high degree of variability in aPTT for any given anti-FXa level (r2= 0.57). Results were discordant in 104 samples (63.8%) from patients undergoing bridging therapy with warfarin and in 149 samples (84.2%) from patients with device obstruction and/or hemolysis (p< 0.001). The most common pattern of discordance was a supratherapeutic aPTT value despite a therapeutic anti-FXa level (49.1% for bridging vs. 75.8% for device obstruction and/or hemolysis; p< 0.001). Conclusions: Levels of aPTT were disproportionately prolonged relative to the corresponding anti-FXa levels in CF-LVAD patients, particularly those with device obstruction. Hemolysis and warfarin administration may falsely elevate aPTT, resulting in overestimation of heparin concentration and under-anticoagulation. Use of aPTT and anti-FXa to guide heparin therapy may lead to different estimates of heparin concentration in the same patient.

AB - Objectives: This study investigated the relationship between anti-factor Xa (anti-FXa) and activated partial thromboplastin time (aPTT) for monitoring intravenous unfractionated heparin (IV-UFH) in patients with continuous-flow left ventricular assist devices (CF-LVADs). Background: CF-LVADs have become mainstream therapy for patients with advanced heart failure. Thromboembolic events, device thrombosis, and bleeding continue to be a challenge with this technology. Adequate anticoagulation is required to prevent these adverse events. Methods: A prospective study of consecutive patients implanted with a CF-LVAD was conducted. Paired samples were considered concordant if aPTT values fell into expected ranges for subtherapeutic, therapeutic, and supratherapeutic anti-FXa levels. Heparin dosing was on the basis of anti-Xa levels. Results: A total of 340 paired values from 38 patients were evaluated. Anti-FXa and aPTT were discordant in 253samples (74.4%), with a high degree of variability in aPTT for any given anti-FXa level (r2= 0.57). Results were discordant in 104 samples (63.8%) from patients undergoing bridging therapy with warfarin and in 149 samples (84.2%) from patients with device obstruction and/or hemolysis (p< 0.001). The most common pattern of discordance was a supratherapeutic aPTT value despite a therapeutic anti-FXa level (49.1% for bridging vs. 75.8% for device obstruction and/or hemolysis; p< 0.001). Conclusions: Levels of aPTT were disproportionately prolonged relative to the corresponding anti-FXa levels in CF-LVAD patients, particularly those with device obstruction. Hemolysis and warfarin administration may falsely elevate aPTT, resulting in overestimation of heparin concentration and under-anticoagulation. Use of aPTT and anti-FXa to guide heparin therapy may lead to different estimates of heparin concentration in the same patient.

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KW - Intravenous unfractionated heparin

KW - LDH

KW - Monitoring

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