PB0938 - Clinical Factors Associated with Low Antithrombin Activity Among Patients with Acute Pulmonary Embolism: The Thromboembolism Heparinization and AntithrombiN Observational Study (THANOS)

Monday, June 24, 2024

13:45 – 14:45 ICT

Room: Exhibition Hall

Presenting Author(s)

Christiana K. Prucnal MD ScM, MD, ScM

Emergency Medicine Resident Physician
Harvard Affiliated Emergency Medicine Program, Boston MA
Dorchester, Massachusetts, United States

Co-Author(s)

GW

Grace Wang MS MPH

Clinical Research Coordinator
Massachusetts General Hospital, Boston MA
Boston, Massachusetts, United States
NH

Nora Horick MS

Biostatistician
Massachusetts General Hospital, Boston MA
Boston, Massachusetts, United States
WH

Weixing Huang MSPH

Biostatistician
Massachusetts General Hospital, Boston MA
Boston, Massachusetts, United States
SU

Sacha Uljon mD PhD

Assistant Professor of Pathology
Massachusetts General Hospital, Boston MA
Boston, Massachusetts, United States
GP

Gregory Peters MD

Resident Physician, Harvard Affiliated Emergency Medicine Residency Program
Massachusetts General Hospital
Boston, Massachusetts, United States
KC

Kyle Chang

Research Collaborator, Center for Vascular Emergencies
Massachusetts General Hospital, Boston MA
Boston, Massachusetts, United States
SH

Savanah Harshbarger MD MBA

Resident Physician, Harvard Affiliated Emergency Medicine Residency Program
Massachusetts General Hospital, Boston, MA
Boston, Massachusetts, United States
ES

Eun Sang Lee

Research Collaborator, Center for Vascular Emergencies
Massachusetts General Hospital
Boston, Massachusetts, United States
ID

Isabel Dhar

Research Coordinator, Center for Vascular Emergencies
Massachusetts General Hospital, Boston, MA
Boston, Massachusetts, United States
TB

Tyleah Brown

Research Coordinator, Center for Vascular Emergencies
Massachusetts General Hospital
Boston, Massachusetts, United States
SF

Sophie Flomenbaum

Research Coordinator
Massachusetts General Hospital
Boston, Massachusetts, United States
DB

Drew Birrenkott MD PhD

Resident Physician, Harvard Affiliated Emergency Medicine Residency Program
Massachusetts General Hospital
Boston, Massachusetts, United States
NG

Nicholas Giodano MS

Research Collaborator
Massachusetts General Hospital
Boston, Massachusetts, United States
TM

Timothy Matthews BS

Research Collaborator, Center for Vascular Emergencies
Massachusetts General Hospital
Boston, Massachusetts, United States
KS

Karsten Stanneck MED

Research Collaborator
Center for Vascular Emergencies
Boston, Massachusetts, United States
Christopher Kabrhel, MD MPH

Director, Center for Vascular Emergencies
Massachusetts General Hospital
Boston, Massachusetts, United States

Background: Why many acute pulmonary embolism (PE) patients do not achieve therapeutic anticoagulation with heparinoids is unknown. One hypothesis posits that acute PE represents an acquired antithrombin (AT)-deficient state, which reduces heparinoid's therapeutic activity. These authors' earlier work found that 80% of patients after acute PE have reduced AT activity (less than 100%).

Aims: To explore the relationship between clinical factors and low AT activity among patients with acute PE.

Methods: We performed this IRB-approved prospective, observational study of consecutive patients diagnosed with acute PE without contraindication for heparinoid anticoagulation at Massachusetts General Hospital, a large urban tertiary referral center. The study was funded through an investigator-initiated grant from Grifols™. We obtained informed consent and blood within 24 hours of PE diagnosis and measured AT activity at the time of diagnosis and over 3 days. We culled history, diagnostic, and management data from electronic medical records. We examined whether intensive care (ICU) admission and length of stay (LOS) were associated with low AT activity. We analyzed whether patients with low AT activity were more likely to experience adverse clinical outcomes. We evaluated the association between low AT and likelihood of adverse clinical outcome using the Chi-squared test and performed univariate logistic regression to identify hospital factors associated with low AT levels.

Results: Of 200 patients, mean age was 6216 years, 120 (60%) were male, 158 (79%) were White, 20 (10%) were Black, and 18 (9%) were Hispanic ethnicity. Low AT levels ( < 80%) were associated with longer LOS (OR = 1.01 [1.00, 1.01] p< 0.0001), ICU admission (OR = 2.69 [1.29, 5.63] p=0.0085) (Table 1), and adverse clinical outcomes (p=0.0042) (Table 2).

Conclusion(s): For patients with acute PE, low initial AT activity at the time of diagnosis is associated with ICU admission, longer LOS, and adverse clinical outcomes.