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2441 COVID-19 Associated 60-Day Acute VTE Events in Hospitalized Patients Can be Predicted By D-Dimer and Prior VTE but Not By Reticulated Platelets

Program: Oral and Poster Abstracts
Session: 301. Vasculature, Endothelium, Thrombosis and Platelets: Basic and Translational: Poster II
Hematology Disease Topics & Pathways:
Bleeding and Clotting, Research, Clinical Research, thromboembolism, SARS-CoV-2/COVID-19, Diseases, Infectious Diseases, real-world evidence
Sunday, December 11, 2022, 6:00 PM-8:00 PM

Bilal Ashraf, MD1*, Haekyung Jeon-slaughter, PhD2*, Nicholas C.J. Lee, MD3, Taha Bat, MD4, Sung-Hee Choi, MD5*, Weina Chen, MD, PhD6*, Abey Thomas, MD1* and Ibrahim F. Ibrahim, MD5

1Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
2Department of Internal Medicine, VA North Texas Health Care System, University of Texas Southwestern Medical Center,, Dallas
3Departments of Internal Medicine and Pediatrics, University of Texas Southwestern, Dallas, TX
4Division of Hematology and Oncology, UT Southwestern Medical Center, Dallas, TX
5Division of Hematology and Oncology, Department of Internal Medicine, University of Texas Southwestern, Dallas, TX
6Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX


COVID-19 is associated with venous thromboembolic (VTE) events, which are predictors for poor outcomes. Beyond d-dimer, there is a dearth of robust studies evaluating the association between VTE and clinical biomarkers. Our prior study established an association between immature platelet fraction (IPF%) and outcomes in COVID-19, specifically mortality and ICU admission. We expand on this by investigating the relationship between IPF% and acute 60-day VTE events in COVID-19 with a larger cohort.


1238 patients admitted with COVID-19 were analyzed. Various demographic factors and laboratory values, including IPF%, d-dimer, and platelet count were extracted. Charts were reviewed for 60-day VTE events. We assessed the relationship between 60-day VTE events and peak IPF% (IPF% max), lowest value of platelet counts (min platelet count), peak values of immature platelet counts (IPC max). In addition, the study also assessed the relationship between acute 60-day VTE events and average IPF% values (mean IPF%), average platelet counts (mean platelet count), maximum d-dimer (d-dimer max), and average d-dimer (mean d-dimer). Kaplan-Meir curves, Cox proportional hazard, and Cox time-varying covariate models were used to conduct time-to-event analyses to test associations between the selected inflammatory biomarker measures and increased risk of 60-day acute VTE events in our cohort.


110 (9%) patients had an acute VTE event within 60 days of COVID-19 diagnosis. Maximum d-dimer is predictive of acute 60-day VTE events in the Cox proportional hazard model (HR 1.04, 95% CI 1.02-1.06, p<0.01). Additionally, prior VTE event is predictive of acute 60-day VTE event in COVID-19 in the Cox proportional hazard model (HR 2.1, 95% CI 1.4-3.8, p<0.01). However, elevated mean IPF% and IPF% max were higher in patients with VTE (IPF% max 6.4±4.7 vs. 5.1±3.3, p=0.0478; mean IPF% 5.1±3.4 vs.4.7±3.8, p=0.0025) (table 1). In the Cox proportional hazard model, neither mean IPF% nor IPF% max are predictive of VTE.


Predictive biomarkers for thromboembolism in COVID-19 is an unmet need. This study demonstrates that prior VTE events and maximum d-dimer are predictive of 60-day VTE events but not reticulated (immature) platelets in hospitalized COVID-19 patients. Current prophylactic anticoagulation recommendations in COVID-19 hospitalized patients are broadly based on the patient’s clinical acuity, and there is a need for more personalized anticoagulation measures. Use of patient VTE history, clinical scenario, and biomarkers, in conjunction, would provide a more patient-centered approach to anticoagulation practice in hospitalized COVID-19 patients.

Disclosures: No relevant conflicts of interest to declare.

*signifies non-member of ASH