Time in Therapeutic Range for Left Ventricular Assist Device Patients Anticoagulated With Warfarin: A Correlation to Clinical Outcomes.
Left ventricular assist devices (LVADs) require anticoagulation therapy with vitamin K antagonists to reduce the risk of thrombotic events. The quality of anticoagulation may be assessed by the time in therapeutic range (TTR). We analyzed a retrospective cohort of LVAD patients at a single institution from January 2012 to September 2014. Primary outcomes included TTR during the study time period and TTR 30 days preceding a bleeding or thrombotic event. Fifty-one patients (mean age 57.0 ± 14.6 years; 78% male) had an overall TTR of 52%. Median international normalized ratio (INR) preceding a bleeding and thrombotic event was 2.7 and 2.2, respectively (p = 0.049). In the 30 days before an event, patients with a bleeding event were more likely to be on low-dose aspirin (37% vs. 12%; p = 0.018) and spend a higher proportion of time above therapeutic range (41% vs. 17%; p = 0.007) compared with those with thrombotic events. The association between a greater percentage of time above therapeutic range in the 30 days before a bleeding event demonstrates the importance of avoiding a supratherapeutic INR in the LVAD patient population and the usefulness of TTR as a measure of the overall quality of anticoagulation and monitoring in an LVAD cohort.
From the *Department of Pharmacy, University of Iowa Hospitals and Clinics, Iowa City, IA (Employed by Abbott Northwestern Hospital During the Development of This Article); †Sanofi US, Bridgewater, NJ (Employed by Abbott Northwestern Hospital During the Development of This Article); ‡Heart Failure Section, Minneapolis Heart Institute Foundation, Research, Minneapolis, MN; and §Heart Failure Section, Abbott Northwestern Hospital, Minneapolis Heart Institute, Minneapolis, MN.
Laura C
LC
Halder
Laura B
LB
Richardson
Ross F
RF
Garberich
Peter
P
Zimbwa
Mosi K
MK
Bennett
D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use*; D005260:Female; D006353:Heart-Assist Devices / Q000009:adverse effects*; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013927:Thrombosis / Q000517:prevention & control; D013997:Time Factors; D014859:Warfarin / Q000627:therapeutic use*
D000925:Anticoagulants; D014859:Warfarin