Abstract Number: PB0056
Meeting: ISTH 2021 Congress
Theme: Coagulation and Natural Anticoagulants » Coagulation Factors and Inhibitors
Background: Despite treatment with low-molecular-weight-heparin as thromboprophylaxis, patients with lower-leg cast immobilization and patients who undergo knee arthroscopy, are at high risk for developing Venous Thromboembolism (VTE). Establishing the mechanism of VTE in these patients could reveal new targets for thromboprophylactic strategies. It is currently unknown whether levels of procoagulant factors are influenced by lower-leg trauma and knee arthroscopy.
Aims: To measure the impact of
(1) lower-leg trauma and
(2) knee arthroscopy on plasma levels of procoagulant factors.
Methods: Blood samples of POT-CAST (Prevention Of Thrombosis following CAST immobilization) and POT-KAST (Prevention Of Thrombosis after Knee Arthroscopy) trial participants were analysed. Blood was collected directly after lower-leg trauma, and ≤4 hours before and after knee arthroscopy. Factor (F)VIII, IX, XI, fibrinogen (FG), von Willebrand Factor (VWF) and D-dimer were measured. For aim 1, we compared measurements in lower-leg injury patients with those in preoperative blood samples of knee arthroscopy patients (controls). Linear regression was used to obtain mean differences, adjusted for age, sex, Body Mass Index (BMI), comorbidities, malignancy, and oral contraceptive use. Data were ln-retransformed in case of skewedness, resulting in mean ratios. For aim 2, we compared pre- and postoperative factor levels of knee arthroscopy patients, using paired t-tests which resulted in mean changes.
Results: In patients with lower-leg injury all procoagulant factor levels were clearly higher than in controls, especially FVIII and VWF (Table 1). After knee arthroscopy, all procoagulant factor levels decreased (Table 2).
| Mean (SD) | Adj. mean difference/ratio (95% CI)†* |
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| Lower-leg injury (N=1204) | Controls (N=1001) |
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| Factor VIII activity (%) | 148.2 (40.7) | 125.2 (29.2) | 26.8 (23.7 to 29.9) |
| Factor IX activity (%) | 135.0 (24.8) | 125.0 (22.4) | 13.8 (11.9 to 15.6) |
| Factor XI activity (%) | 117.1 (23.7) | 114.2 (21.5) | 5.1 (3.3 to 7.0) |
| Von Willebrand Factor (%) | 165.4 (47.7) | 139.9 (39.3) | 29.8 (26.0 to 33.6) |
| Fibrinogen (mg/dL) | 334.9 (91.6) | 311.6 (73.3) | 32.5 (25.8 to 39.2) |
| D-dimer (ng/mL)‡ | 677.8 (641.8 to 715.8) | 214.4 (203.2 to 226.1) | 3.3 (3.1 to 3.6)† |
| * Adjusted for sex, age, BMI, comorbidity, presence of malignancy, use of oral contraceptives. † Mean ratios are denoted in the table with this symbol and in italics. ‡ D-dimer not normally distributed and therefore ln-retransformed, resulting in geometric means with 95%CIs and mean ratios. |
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Aim 1: Mean differences in procoagulant factor levels between patients with lower-leg injury and controls.
| Mean (SD) | Mean change (95% CI)* |
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| Preoperative (N=715) | Postoperative (N=715) | ||
| Factor VIII activity (%) | 123.0 (27.9) | 113.8 (35.7) | -9.1 (-11.1 to -7.1) |
| Factor IX activity (%) | 123.1 (22.0) | 110.1 (21.8) | -12.9 (-14.0 to -11.9) |
| Factor XI activity (%) | 112.4 (20.8) | 101.0 (21.1) | -11.5 (-12.6 to -10.3) |
| Von Willebrand Factor (%) | 139.9 (38.9) | 132.7 (40.4) | -7.2 (-8.6 to -5.7) |
| Fibrinogen (mg/dL) | 308.9 (72.3) | 276.9 (67.3) | -32.1 (-34.7 to -29.5) |
| D-dimer (ng/mL)† | 215.6 (201.5 to 230.7) | 204.7 (193.1 to 216.9) | -53.5 (-88.9 to -18.0) |
| * Mean of difference between preoperative and postoperative paired per patient. † Ln-transformed data because of skewedness, resulting in geometric means. |
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Aim 2: Change of procoagulant factor levels after knee arthroscopy.
Conclusions: In contrast to knee arthroscopy, lower-leg injury was associated with increased plasma levels of procoagulant factors, especially FVIII and VWF, suggesting a different underlying pathophysiology of VTE in these patient groups.
To cite this abstract in AMA style:
Touw CE, Nemeth B, Schipper I, Nelissen R, Cannegieter S. The Impact of Lower-leg Injury and Knee Arthroscopy on Procoagulant Factor Levels [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/the-impact-of-lower-leg-injury-and-knee-arthroscopy-on-procoagulant-factor-levels/. Accessed December 6, 2023.« Back to ISTH 2021 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/the-impact-of-lower-leg-injury-and-knee-arthroscopy-on-procoagulant-factor-levels/