OC 23.1 - Management of Patients with Unprovoked Venous Thromboembolism and a Low Risk of Recurrence with the Vienna Prediction Model: A Prospective Cohort Study

Sunday, July 10, 2022

2:45 PM – 3:00 PM

Location: ExCel Center, ICC Capital Suite Room 7&12

Presentation Format: In-Person

Presenting Author(s)

Sabine Eichinger, MD

Professor
Medical University of Vienna, Department of Medicine I
Vienna, Wien, Austria

Co-Author(s)

LE

Lisbeth Eischer

MD
Medical University of Vienna
Wien, Wien, Austria
HS

Hana Sinkovec

Biostatistician
Medical University of Vienna
Wien, Wien, Austria
PG

Paul Gressenberger

MD
Medical University of Graz
Graz, Steiermark, Austria
TG

Thomas Gary

Professor
Medical University Graz
Graz, Steiermark, Austria
MB

Marianne Brodmann

Professor
Medical University Graz
Graz, Steiermark, Austria
GH

Georg Heinze

Professor of Statistics
Medical University of Vienna
Wien, Wien, Austria
PK

Paul A. Kyrle

Professor
Medical University of Vienna, Department of Medicine I
Vienna, Wien, Austria

Background: Patients with unprovoked venous thromboembolism (VTE) have a high recurrence risk and should receive extended oral anticoagulation (OAC). OAC may cause bleeding, and patients at low recurrence risk could benefit from limited OAC duration.

Aims: In a prospective management study, we evaluated the recurrence risk of VTE patients with a low recurrence risk predicted by the Vienna Prediction Model (VPM).

Methods: 520 patients with a first unprovoked VTE and a predicted one-year recurrence risk of < 4.4% by the VPM were included after OAC discontinuation. Exclusion criteria were previous VTE, VTE provoked by a temporary risk factor, by female hormone intake, cancer, known major thrombophilia, OAC >7 months or OAC for reasons other than VTE. Follow-up was 2 years. The main outcome was recurrent VTE. One-year and two-years recurrence risks of 8% and 13% were pre-specified as safety margins. Cumulative recurrence risk was estimated using the Kaplan-Meier method. The VPM was recalibrated by adjusting the cumulative baseline risk to the observed values.

Results: Of 520 patients [median age 52; IQR42-65 years, 289 (56%) men, 226 (43%) pulmonary embolism, 206 (40%) proximal and 88 (17%) distal deep vein thrombosis], 52 patients (30 men) had non-fatal recurrent VTE (5.8/100 patient-years, 95%CI 4.4-7.7). After one year the cumulative recurrence risk (5.2%, 95%CI 3.2-7.2) was significantly lower than the pre-specified safety margin of 8% (p=0.003). After 2 years the cumulative incidence (11.2%, 95%CI 8.3-14) was not significantly lower than the safety margin of 13% (p=0.11). Because of the underestimated risk during the 2 year, we recalibrated the VPM. The VPM now allows stratification of low-risk patients into different categories (Figure 1).

Conclusion(s): The recalibrated VPM identifies patients with unprovoked VTE at low risk of recurrence. Applying the VPM refines risk stratification, which facilitates treatment decisions on the duration of OAC.