Obesity is associated with postinjury hypercoagulability

Abstract

Background: Obesity is linked to hypercoagulability with an increased risk of venous thromboembolic events (VTE) in the uninjured population. Therefore, we hypothesize that obesity (Body Mass Index (BMI) ≥30 kg/m2) is associated with a hypercoagulable state postinjury characterized by increased clot strength and resistance to fibrinolysis. Methods: Our prospective Trauma Activation Protocol database includes all trauma activations patients for whom a rapid thrombelastography (TEG) is obtained within 60 minutes postinjury prior to any transfusions. The dataset was then stratified by BMI and subjects with BMI ≥ 30 kg/m2 were compared to those with BMI<30 kg/m2). The following TEG measurements were obtained: activated clotting time (ACT), clot formation rate (angle), maximum clot strength (MA), and % clot lysis 30 min after MA (LY30, %). Fibrinolysis shutdown (SD) was defined as LY30 < 0.6% and hyperfibrinolysis (HF) as LY30 > 7.6%. Continuous variables are expressed as median (IQR). Results: Overall, 687 patients were included of whom 161 (23%) had BMI ≥ 30kg/m2 (BMI30). The BMI30 group was older, had a lower proportion of males and of blunt trauma, and were less severely injured. After adjustment for confounders, BMI30 was independently associated with lower odds of MA<55mm (OR 0.28; 95% CI 0.130.60) and of HF (OR 0.31; 95% CI 0.10–0.97) and higher odds of SD (OR 1.82; 95% CI 1.09–3.05). No independent association was observed with angle<650 (OR 0.57 95% CI 0.30–1.05). While VTEs were more frequent among BMI30 patients (5.0 vs 3.3%), this did not reach significance after confounding adjustment (p=0.11). Conclusion: Obesity was protective against diminished clot strength and hyperfibrinolysis, and obesity was associated with an increased risk of fibrinolytic shutdown in severely injured patients. These findings suggest a relative hypercoagulability. Although no difference in VTEs was noted in this study, these findings may explain the higher rate of VTEs reported in other studies.

The risk of thromboembolic events with early intravenous 2‐ and 4‐g bolus dosing of tranexamic acid compared to placebo in patients with severe traumatic bleeding: A secondary analysis of a randomized, double‐blind, placebo‐controlled, single‐center trial

“…In our adjusted analyses increased BMI, increased time from injury to TXA administration, and increased amount of blood transfusions were all independently associated with increased risk of thromboembolism. This is consistent with the literature that indicates hypercoagulability and increased risk of thrombotic events in patients with obesity 19–22 . The independent association with thromboembolism and later use of TXA within a 2‐h time frame from injury may be due to increased endothelial injury, inflammation, and hypercoagulability that increases from the time of admission to 6 h after admission in severely injured patients, as is demonstrated by increasing concentrations of syndecan‐1, IL‐8, PF1.2, and D‐dimer during this time frame in the study (Figure 2).…”

“…This is consistent with the literature that indicates hypercoagulability and increased risk of thrombotic events in patients with obesity. [19][20][21][22] The independent association with thromboembolism and later use of TXA within a 2-h time frame from injury may be due to increased endothelial injury, inflammation, and hypercoagulability that increases from the time of admission to 6 h after admission in severely injured patients, as is demonstrated by increasing concentrations of syndecan-1, IL-8, PF1.2, and D-dimer during this time frame in the study (Figure 2). The mechanisms for the role of TXA increasing the risk of thrombotic events for patients with laboratory measures of increased endothelial injury, inflammation, and clot formation require additional investigation.…”

“…Increased risk of thrombosis has been reported with increased BMI, ISS, IL-8, and with increased transfusion of blood products. [19][20][21][22][23][24][25][26] Time from injury to use of TXA was included based on the hypothesis that inflammation increases over time and the use of TXA in a patient with increased inflammation may increase the risk of thrombosis. Syndecan-1 and D-dimer concentrations were also considered a priori as covariates but were excluded due to the high rate of missing data for both of these variables which precluded the use of these variables in the model.…”

“…Covariates were determined a priori and included time from injury to intervention, BMI, ISS, IL‐8 concentration, and transfused blood volume. Increased risk of thrombosis has been reported with increased BMI, ISS, IL‐8, and with increased transfusion of blood products 19–26 . Time from injury to use of TXA was included based on the hypothesis that inflammation increases over time and the use of TXA in a patient with increased inflammation may increase the risk of thrombosis.…”

Chinese expert consensus on diagnosis and treatment of trauma-induced hypercoagulopathy

“…However, VTE risk was lower among patients older than 50 years than among younger patients [ 16 ]. In a prospective study of 687 trauma patients to examine the relationship between obesity [body mass index (BMI) ≥ 30 kg/m 2 ] and post-injury hypercoagulability, obese patients showed higher MA values, lower fibrinolysis [clot lysis achieved 30 min after MA (LY30%)], and higher incidence of VTE than non-obese patients [ 17 ]. A study of 72 morbidly obese patients undergoing bariatric surgery showed that the average BMI of obese patients decreased from 44.6 kg/m 2 to 31.4 kg/m 2 by 6 months after surgery.…”