PB0992 - Impact of thrombocytopenia on bleeding and thrombotic complications in patients with atrial fibrillation starting anticoagulation: a time varying analysis.

Tuesday, June 25, 2024

13:45 – 14:45 ICT

Room: Exhibition Hall

Presenting Author(s)

Kevin J. Barnum, MD PhD

Fellow
Beth Israel Deaconess Medical Center
Boston, Massachusetts, United States

Co-Author(s)

VI

Varun Iyengar

Fellow
Memorial Sloan Kettering Cancer Center
New York, New York, United States
LD

Laura Dodge

Assistant Professor of Obstetrics, Gynecology and Reproductive Biology
Beth Israel Deaconess Medical Center
Boston, Massachusetts, United States
SM

Sirui Ma

Resident physician
Beth Israel Deaconess Medical Center
Boston, Massachusetts, United States
AB

Amelia Barnett

Resident physician
Beth Israel Deaconess Medical Center
Boston, Massachusetts, United States
PE

Pavania Elavalakanar

OMS-I
University of New England College of Osteopathic Medicine
Portland, Maine, United States
Jeffrey I. Zwicker, MD

Chief of Hematology Service
Hematology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
New York, New York, United States
Rushad Patell, MBBS

Assistant Professor
Beth Israel Deaconess Medical Center
Boston, Massachusetts, United States

Background: We previously observed that baseline thrombocytopenia increases bleeding and thrombosis risk in patients with atrial fibrillation (AF). Whether risk of bleeding or thrombosis is directly related to periods of thrombocytopenia was not established.

Aims: To determine risk of bleeding, arterial thromboembolism (ATE), and venous thromboembolism (VTE) associated with thrombocytopenia in patients with AF starting anticoagulation.

Methods: We performed a retrospective analysis of patients initiating oral anticoagulation for AF between 2015-2020. The primary endpoint was clinically-relevant bleeding (CRB) (composite of major bleeding (MB) and clinically-relevant non-major bleeding (CRNMB)). Secondary outcomes were ATE and VTE. Outcomes were analyzed using Cox proportional hazards models with thrombocytopenia ( < 100 x103/μL) as a time-varying exposure, adjusting for demographics, comorbidities and antiplatelet and anticoagulant agents at start of anticoagulation.

Results: We included 1,088 patients with median age 72 years, 61.8% male, 20.2% with hypertension, and 13.7% with cancer. 201 patients (18.5%) experienced bleeding within one year; including 4 (0.4%) fatal bleeds, 94 (8.6%) MB, and 118 (10.8%) CRNMB. 39 patients (3.6%) experienced a thrombotic event. Periods of thrombocytopenia ( < 100x103/ml) were associated with higher risk of CRB (1.72, 95% CI: 1.07–2.77). Bleeding risk was more pronounced during periods of severe thrombocytopenia ( < 75 x103/μL) for CRB (HR: 3.85, 95% CI: 2.15–6.90). In both models, prior bleed was associated with the risk of CRB (both p< 0.001). (Table 1)

Severe thrombocytopenia ( < 75 x103/μL) was associated with increased risk of thrombosis (ATE+VTE) (HR 7.19, 95% CI: 2.66–19.1) respectively. No other covariate was associated with thrombosis (all P>0.09). (Table 2)

Conclusion(s): Thrombocytopenia was associated with significantly increased risk of bleeding and thrombosis in patients with AF starting anticoagulation. These data support the need to individualize therapy around the dynamic thrombotic and bleeding risk by platelet count.