Sirtaz Adatya1, Nir Uriel2, Hirad Yarmohammadi3, Christopher T Holley3, Amy Feng3, Samit S Roy3, Mark T Reding4, Ranjit John3, Peter Eckman3, Nicole D Zantek5. 1. Department of Medicine, Cardiology Division, University of Minnesota, Minneapolis, Minnesota. Electronic address: snadatya@umn.edu. 2. Department of Medicine, Cardiology Division, University of Chicago, Chicago, Illinois. 3. Department of Medicine, Cardiology Division, University of Minnesota, Minneapolis, Minnesota. 4. Department of Medicine, Division of Hematology, Oncology and Transplantation, University of Minnesota, Minneapolis, Minnesota. 5. Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota.
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 253 samples (74.4%), with a high degree of variability in aPTT for any given anti-FXa level (r(2) = 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.
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 253 samples (74.4%), with a high degree of variability in aPTT for any given anti-FXa level (r(2) = 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-LVADpatients, 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.
Authors: Noah Weingarten; Cindy Song; Amit Iyengar; David Alan Herbst; Mark Helmers; Danika Meldrum; Sara Guevara-Plunkett; Jessica Dominic; Pavan Atluri Journal: Indian J Thorac Cardiovasc Surg Date: 2022-09-21
Authors: Finn Gustafsson; Binyamin Ben Avraham; Ovidiu Chioncel; Tal Hasin; Avishai Grupper; Aviv Shaul; Sanemn Nalbantgil; Yoav Hammer; Wilfried Mullens; Laurens F Tops; Jeremy Elliston; Steven Tsui; Davor Milicic; Johann Altenberger; Miriam Abuhazira; Stephan Winnik; Jacob Lavee; Massimo Francesco Piepoli; Lorrena Hill; Righab Hamdan; Arjang Ruhparwar; Stefan Anker; Marisa Generosa Crespo-Leiro; Andrew J S Coats; Gerasimos Filippatos; Marco Metra; Giuseppe Rosano; Petar Seferovic; Frank Ruschitzka; Stamatis Adamopoulos; Yaron Barac; Nicolaas De Jonge; Maria Frigerio; Eva Goncalvesova; Israel Gotsman; Osnat Itzhaki Ben Zadok; Piotr Ponikowski; Luciano Potena; Arsen Ristic; Tiny Jaarsma; Tuvia Ben Gal Journal: ESC Heart Fail Date: 2021-09-28