Risks of major bleeding and venous thromboembolism in patients undergoing total hip or total knee arthroplasty using therapeutic dosages of DOACs.

About 1.5% of patients undergoing total hip (THA) or total knee arthroplasty (TKA) still develop postoperative venous thromboembolism (VTE), indicating that the current thromboprophylaxis strategy is not optimal. To evaluate the feasibility of therapeutic dosages of direct oral anticoagulants (DOACs) as thromboprophylaxis for high VTE risk patients, we determined the risks of major bleeding and VTE in patients who underwent THA/TKA and were treated with DOACs in therapeutic dosages for atrial fibrillation (AF). We conducted a registry-based cohort study from 2010 to 2018 in Denmark and included AF patients on therapeutic DOACs dose who underwent THA/TKA. AF patients were utilized as proxy since they have a life-long indication for therapeutic anticoagulant medication. The 49-days cumulative incidence (with death as competing risk) of major bleeding was assessed. The same was done for VTE at 49- and 90-days. 1,354 THA and TKA procedures were included. The 49-days cumulative incidence of major bleeding was 1.40% (95%Confidence Interval[CI] 0.88-2.14%). Most bleeding events occurred at the surgical site. The cumulative incidence of VTE at 49-days was 0.59% (95%CI 0.28-1.13%) and 0.74% (95%CI 0.38-1.32%) at 90-days. The incidence of major bleeding in THA/TKA patients on DOACs in therapeutic dosages was in line with previously reported incidences among THA/TKA patients on thromboprophylaxis dosages, while the incidence of VTE was relatively low. These data provide a solid basis for the design of randomized controlled trials to establish the safety and efficacy of therapeutic dosages of DOACs to prevent VTE in high-risk patients.

Venous Thromboembolism Prophylaxis in Foot and Ankle Surgery: A Worldwide Survey.

Current recommendations on thromboprophylaxis for foot and ankle (FA) surgery are often inconsistent and generally based on weak evidence. The aim of this survey study was to evaluate the current practice among orthopedic surgeons regarding venous thromboembolism (VTE) prophylaxis following FA surgery. From February 2019 to March 2020, an online questionnaire was sent by e-mail to orthopedic societies across the world. The questionnaire was hosted by the International Society of Thrombosis and Haemostais RedCAP platform. Topics of interest were VTE rates following FA surgery, duration and type of thromboprophylaxis, bleeding complications, VTE risk factors for prophylaxis and use of risk assessment. A total of 693 FA orthopedic surgeons from all continents completed the survey of whom 392 (57%) performed more than 200 FA procedures per year. A total of 669/693 (97%) respondents stated that thromboprophylaxis is necessary in FA surgeries. When thromboprophylaxis was prescribed, half of surgeons prescribed it for the duration of immobilization. Acetylsalicylic acid, low molecular weight heparin and direct-oral anticoagulants were, in this order, the preferred choice. Acetylsalicylic acid and low molecular weight heparin were predominantly prescribed in North America and Europe, respectively. Previous deep vein thrombosis, immobility, obesity and inherited thrombophilia were considered the main risk factors indicative of thromboprophylaxis use. In this survey, most surgeons agree that thromboprophylaxis is indicated for FA surgery, but the prescription, type and duration of prophylaxis differs greatly with a large intercontinental discrepancy. These survey results could be a foundation for developing uniform guidelines to optimize thromboprophylactic strategies in FA procedures around the world.

Development and validation of a clinical prediction model for 90-day venous thromboembolism risk following total hip and total knee arthroplasty: a multinational study.

BACKGROUND: The risk of venous thromboembolism (VTE) following total hip arthroplasty (THA) and total knee arthroplasty (TKA) is 1.0% to 1.5%, despite uniform thromboprophylaxis. OBJECTIVES: To develop and validate a prediction model for 90-day VTE risk. METHODS: A multinational cohort study was performed. For model development, records were used from the Oxford Royal College of General Practitioners Research and Surveillance Centre linked to Hospital Episode Statistics and Office of National Statistics UK routine data. For external validation, data were used from the Danish Hip and Knee Arthroplasty Registry, the National Patient Registry, and the National Prescription Registry. Binary multivariable logistic regression techniques were used for development. RESULTS: In the UK data set, 64 032 THA/TKA procedures were performed and 1.4% developed VTE. The prediction model consisted of age, body mass index, sex, cystitis within 1 year before surgery, history of phlebitis, history of VTE, presence of varicose veins, presence of asthma, history of transient ischemic attack, history of myocardial infarction, presence of hypertension and THA or TKA. The area under the curve of the model was 0.65 (95% CI, 0.63-0.67). Furthermore, 36 169 procedures were performed in the Danish cohort, of whom 1.0% developed VTE. Here, the area under the curve was 0.64 (95% CI, 0.61-0.67). The calibration slope was 0.92 in the validation study and 1.00 in the development study. CONCLUSION: This clinical prediction model for 90-day VTE risk following THA and TKA performed well in both development and validation data. This model can be used to estimate an individual's risk for VTE following THA/TKA.

Enhanced in vivo and ex vivo thrombin generation after lower-leg trauma, but not after knee arthroscopy.

BACKGROUND: There is room for improvement of prevention of venous thromboembolism (VTE) after lower-leg cast application or knee arthroscopy. Information about the mechanism of clot formation in these patients may be useful to identify new prophylaxis targets. We aimed to study the effect of 1) lower-leg injury and 2) knee arthroscopy on thrombin generation. METHODS: A cross-sectional study was conducted using plasma samples of POT-(K)CAST trials to measure ex vivo thrombin generation (Calibrated Automated Thrombography [CAT]) and plasma levels of prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin (TAT), fibrinopeptide A (FPA). Plasma was obtained shortly after lower-leg trauma or before and after (< 4 h) knee arthroscopy. Participants were randomly selected from those who did not develop VTE. For aim 1, samples of 88 patients with lower-leg injury were compared with 89 control samples (i.e., preoperative samples of arthroscopy patients). Linear regression was used to obtain mean differences (or ratios if ln-retransformed because of skewedness) adjusted for age, sex, body mass index, comorbidities. For aim 2, pre- and postoperative samples of 85 arthroscopy patients were compared, for which mean changes were obtained. RESULTS: In patients with lower-leg injury (aim 1), endogenous thrombin potential, thrombin peak, velocity index, FPA and TAT were increased as compared with controls. In arthroscopy patients (aim 2), pre- and postoperative levels were similar for all parameters. CONCLUSION: Lower-leg trauma increases thrombin generation both ex vivo and in vivo, in contrast to knee arthroscopy. This may imply that the pathogenesis of VTE is different in both situations.

The influence of lower-leg injury and knee arthroscopy on natural anticoagulants and fibrinolysis.

BACKGROUND: Patients with lower-leg injuries and those undergoing knee arthroscopy are at increased risk of developing venous thromboembolism. The mechanism is unknown, including the influence of lower-leg injury and knee arthroscopy on natural anticoagulant factors and fibrinolysis. OBJECTIVES: To study the effect of lower-leg injury and knee arthroscopy on plasma levels of anticoagulant and fibrinolytic factors. METHODS: We applied the following 2 designs to investigate this effect: a cross-sectional study for lower-leg trauma and a before-and-after study for knee arthroscopy. Plasma samples of POT-CAST- and POT-KAST-randomized clinical trial participants (collected shortly after lower-leg trauma or before or after arthroscopy) were analyzed for clot lysis time and levels of antithrombin, tissue factor pathway inhibitor, protein C, free protein S, plasminogen, tissue plasminogen activator, plasminogen activator inhibitor 1, antiplasmin, thrombin activatable fibrinolysis inhibitor, plasmin-antiplasmin, and D-dimer. For the effect of lower-leg injury, samples of 289 patients were compared with preoperative samples of 293 arthroscopy patients, acting as controls using linear regression and adjusting for age, sex, body mass index, comorbidities, and diurnal variation. For the effect of knee arthroscopy, mean changes were calculated for 277 patients using linear mixed models adjusted for diurnal variation. Parameters other than CLT and D-dimer were measured in smaller subsets. RESULTS: In lower-leg injury patients, most parameters were stable, whereas D-dimer increased. After arthroscopy, most parameters decreased (especially clot lysis time, D-dimer, plasminogen, and anticoagulant factors), whereas tissue plasminogen activator and thrombin activatable fibrinolysis inhibitor slightly increased. CONCLUSION: In contrast to lower-leg injury, knee arthroscopy was associated with decreased natural anticoagulant factor levels. Neither lower-leg injury nor knee arthroscopy affected in vivo fibrinolysis.

The risk of venous thromboembolism after minor surgical procedures: A population-based case-control study.

BACKGROUND: Surgery is a well-known risk factor for venous thromboembolism (VTE). However, for several minor surgical procedures, thromboprophylaxis is not advised. OBJECTIVES: These "low-risk" procedures include a wide variation of interventions for which we estimated the VTE risk to verify their "low-risk" status. PATIENTS/METHODS: We used data from a large population-based case-control study (Multiple Environment and Genetic Assessment study) into causes of VTE, and linked these to the Dutch Hospital Data Registry to identify exposure to surgical procedures. Logistic regression was used to calculate odds ratios for the 90-day and 1-year relative risks of VTE following these procedures, which were adjusted for body mass index (BMI), sex, age, comorbidities, and infection/inflammation. RESULTS: We included 4247 patients with VTE and 5538 control subjects. Median age and BMI were 48.5 years and 25.5 m2/kg, respectively. Nine unique procedures or groups of procedures were analyzed. One hundred twenty-three participants-90 cases and 33 controls-had undergone a minor procedure within 90 days of the index date, resulting in a 3.5-fold (OR, 3.5; 95% CI, 2.3-5.3) overall increased VTE risk. Furthermore, venous stripping (OR, 7.2; 95% CI, 2.4-21.2), open abdominal/inguinal hernia repair (OR, 3.7; 95% CI, 1.2-11.6), and laparoscopic cholecystectomy (OR, 3.2; 95% CI, 1.0-10.6) were associated with an increased risk. Other minor procedures were less strongly or not associated with an increased risk. In the 1-year period before the index date, all odds ratios were lower. CONCLUSION: Of the "low-risk" procedures, we found that venous stripping, open abdominal/inguinal hernia repair, and laparoscopic cholecystectomy were associated with a clearly increased risk of VTE within 90 postoperative days.

Prevention of hip fractures in older adults residing in long-term care facilities with a hip airbag: a retrospective pilot study.

BACKGROUND: Hip and pelvic fractures do commonly occur among older adults. This pilot study aimed to evaluate the effect of introduction of the WOLK hip airbag on the incidence of hip fractures. METHODS: A retrospective study was performed among 969 participants residing within 11 long-term care facilities for older patients, belonging to one large healthcare organization in The Netherlands. The intervention concerned application of 45 WOLK hip-airbags, distributed among selected residents of the long-term care facilities. Inclusion criteria; physically active participants with a pelvic circumference between 90-125 cm able to wear the hip airbag. Exclusion criteria; participants who continuously removed the hip airbag themselves or participants who depended on a wheelchair for mobility. Main outcome measures were the occurrence of falls and hip, pelvic and other fractures. RESULTS: The incidence of hip and pelvic fractures declined from 3.3/100 person years to 1.8/100 person years during the study for an Incidence Rate Ratio (IRR) of 0.55 (95% confidence interval (95%CI) 0.34-0.87) in the entire study population. The incidence of other fractures did not decline during the study period (IRR 0.72;95%CI 0.37-1.40). The incidence of falls declined to some extent during the study (IRR 0.88; 95%CI 0.83-0.93). CONCLUSIONS: After introduction of the WOLK hip airbag a reduction of the incidence of hip and pelvic fractures by almost half was observed in older patients residing in long-term care facilities, even though only 45 hip airbags were distributed among the 969 residents. As selection bias cannot be ruled out in this study, the results of this pilot study warrant replication by a future clinical trial to determine true effectiveness of this intervention.

Effect of lower-leg trauma and knee arthroscopy on procoagulant phospholipid-dependent activity.

Background: Lower-leg injury and knee arthroscopy are both associated with venous thromboembolism (VTE). The mechanism of VTE in both situations is unknown, including the role of procoagulant microparticles. This may provide useful information for individualizing thromboprophylactic treatment in both patient groups. Objective: We aimed to study the effect of (1) lower-leg trauma and (2) knee arthroscopy on procoagulant phospholipid-dependent (PPL) activity plasma levels. Methods: POT-(K)CAST trial participants who did not develop VTE were randomly selected for the current study. Plasma was collected shortly after lower-leg trauma or before and after knee arthroscopy. For aim 1, samples of 67 patients with lower-leg injury were compared with control samples (preoperative samples of 74 patients undergoing arthroscopy). Linear regression was used to obtain mean ratios (natural logarithm retransformed data), adjusted for age, sex, body mass index, infections, and comorbidities. For aim 2, pre- and postoperative samples of 49 patients undergoing arthroscopy were compared using paired t tests. PPL activity was measured using modified activated factor X-dependent PPL clotting assay. Results: For aim 1, PPL activity levels were almost threefold higher in patients with lower-leg injury compared with controls, that is, mean ratio, 2.82 (95% confidence interval [CI], 1.98-4.03). For aim 2, postoperative PPL activity levels did not change significantly, that is, mean change, -0.72 mU/mL (95% CI, -2.03 to 0.59). Conclusion: Lower-leg trauma was associated with increased plasma levels of PPL activity, in contrast to knee arthroscopy. Lower-leg trauma triggers the release of procoagulant microparticles.

Lower-leg injury and knee arthroscopy have distinct effects on coagulation.

It is unknown how lower-leg injury and knee arthroscopy, both associated with venous thromboembolism (VTE), affect coagulation. To study the effect of (1) lower-leg trauma and (2) knee arthroscopy on coagulation, plasma samples of the Prevention of Thrombosis following CAST immobilization (POT-CAST, #NCT01542762) and Prevention of Thrombosis following Knee Arthroscopy (POT-KAST, #NCT01542723) trials were used, which were collected shortly after lower-leg trauma and before/after (<4 hours) knee arthroscopy. For aim 1, 1204 lower-leg injury patients were compared with preoperative samples of 1001 controls. Mean differences/ratios (if ln-retransformed because of skewedness) were adjusted for sex, age, body mass index, comorbidity, malignancy, and oral contraceptives using linear regression. For aim 2, perioperative mean changes of 715 arthroscopy patients were calculated. Plasma levels of fibrinogen, factor (F)VIII, FIX, FXI, von Willebrand Factor (VWF), and D-dimer were measured in all individuals. Parameters of underlying mechanisms (tissue factor, interleukin-6 [IL-6], myeloperoxidase DNA, cell-free DNA) were measured in random subsets. In lower-leg injury patients, coagulation parameter levels increased, especially FVIII, VWF, and D-dimer, that is, adjusted mean differences: FVIII 26.8% (95% confidence interval [CI], 23.7-29.9), FIX 13.8% (95% CI, 11.9-15.6), FXI 5.1% (95% CI, 3.3-7.0), VWF 29.8% (95% CI, 26.0-33.6), fibrinogen 32.5 mg/dL (95% CI, 25.8-39.2), and D-dimer (mean ratio) 3.3 (95% CI, 3.1-3.6). Remaining parameters were unchanged, except for increased IL-6 levels. After arthroscopy, all parameters decreased. Lower-leg trauma is associated with increased procoagulant factor levels in contrast to knee arthroscopy. This suggests that, in both situations, different pathways are involved in development of VTE.

Targeted proteomics for evaluating risk of venous thrombosis following traumatic lower-leg injury or knee arthroscopy.

INTRODUCTION: Patients with lower-leg cast immobilization and patients undergoing knee arthroscopy have an increased risk of venous thrombosis (VT). Guidelines are ambiguous about thromboprophylaxis use, and individual risk factors for developing VT are often ignored. To assist in VT risk stratification and guide thromboprophylaxis use, various prediction models have been developed. These models depend largely on clinical factors and provide reasonably good C-statistics of around 70%. We explored using protein levels in blood plasma measured by multiplexed quantitative targeted proteomics to predict VT. Our aim was to assess whether a VT risk prediction model based on absolute plasma protein quantification is possible. METHODS: We used internal standards to quantify proteins in less than 10 µl plasma. We measured 270 proteins in samples from patients scheduled for knee arthroscopy or with lower-leg cast immobilization. The two prospective POT-(K)CAST trails allow complementary views of VT signature in blood, namely pre and post trauma, respectively. From approximately 3000 patients, 31 patients developed VT who were included and matched with double the number of controls. RESULTS: Top discriminating proteins between cases and controls included APOC3, APOC4, APOC2, ATRN, F13B, and F2 in knee arthroscopy patients and APOE, SERPINF2, B2M, F13B, AFM, and C1QC in patients with lower-leg cast. A logistic regression model with cross-validation resulted in C-statistics of 88.1% (95% CI: 85.7-90.6%) and 79.6% (95% CI: 77.2-82.0%) for knee arthroscopy and cast immobilization groups respectively. CONCLUSIONS: Promising C-statistics merit further exploration of the value of proteomic tests for predicting VT risk upon additional validation.

Preventing VTE following total hip and knee arthroplasty: Is prediction the future?

Venous thromboembolism (VTE) is a common complication following total hip arthroplasty (THA) and total knee arthroplasty (TKA). Many guidelines advise on the ideal pharmacological thromboprophylaxis strategy; however, despite its use, approximately 1.5% of patients still develop symptomatic VTE. Considering the large number of THAs and TKAs performed worldwide (2.5 million in total), the impact of VTE following these interventions is enormous. This paper discusses a concept how to further lower rates of VTE and bleeding complications following surgery. By stratifying patients according to their risk, we can optimize the balance between VTE and bleeding for each individual. This way, low-risk patients may be safely withheld from treatment (and avoid unnecessary bleeding complications and costs), whereas high-risk patients should receive adequate therapy (for instance, an increased thromboprophylaxis dosage and duration). An individualized strategy requires a well-functioning VTE prediction model following THA and TKA to help physicians to decide on optimal thromboprophylaxis therapy.

Effect of type 1 diabetes and type 2 diabetes on the risk of venous thromboembolism.

AIMS: Whether diabetes increases venous thromboembolism (VTE) is unclear. Any greater risk may relate to insulin resistance, but many studies did not differentiate between type 1 diabetes and type 2 diabetes for VTE risk. METHODS: Retrospective cohort study of the Royal College of General Practitioners Research and Surveillance Centre, comprising over 530 primary care practices. We determined whether type 1 diabetes and/or type 2 diabetes are independent risk factors for VTE. The index date was 1 January 2009, individuals were followed to 31 December 2018, or censoring. Cox proportional hazard regression analysis was used to investigate the risk of VTE in people with type 1 diabetes and type 2 diabetes relative to no diabetes. The primary outcome was occurrence of VTE. The model was adjusted for potential confounders for VTE. RESULTS: There were 7086 people with type 1 diabetes and 95,566 with type 2 diabetes, diagnosed before 1 January 2009. The non-diabetes group consisted of 1,407,699 people. In the unadjusted analysis, there was no increased risk of VTE with type 1 diabetes (HR 1.00, 95% CI 0.76-1.33) but there was for type 2 diabetes (HR 2.70, 95% CI 2.57-2.84). In the fully adjusted model, VTE risk was increased in type 1 diabetes (HR 1.46, 95% CI 1.11-1.92), but not with type 2 diabetes (HR 1.06, 95% CI 0.98-1.14). CONCLUSIONS: Type 1 diabetes was associated with a greater risk for VTE while type 2 diabetes was not. Further work is needed to determine the reason(s) for this.

High risk of venous thromboembolism after orthopedic surgery in patients with thrombophilia.

OBJECTIVE: This study aimed at evaluating the effect of thrombophilia on the risk of venous thromboembolism (VTE) in patients undergoing any type of orthopedic surgery. BACKGROUND: Patients undergoing orthopedic surgery are at high risk for VTE. Although patients with thrombophilia have an increased risk of VTE, it is currently unclear whether there is a synergetic effect in patients with thrombophilia who undergo orthopedic surgery. METHODS: Data from a large population-based case-control study (the Multiple Environmental and Genetic Assessment [MEGA] of risk factors for venous thrombosis study) were used. Odds ratios (ORs) with 95% confidence intervals (CIs), adjusted for age, sex, and body mass index (BMI) (ORadj) were calculated for patients undergoing any orthopedic intervention. RESULTS: Of 4721 cases and 5638 controls, 263 cases and 94 controls underwent orthopedic surgery. Patients who had any orthopedic intervention in the year before the index date were at higher risk of VTE (ORadj 3.7; 95% CI, 2.9-4.8) than those who did not undergo any orthopedic surgery. There was an additionally increased risk in patients with factor V Leiden (OR 17.5, 95% CI, 4.1-73.6), non-O blood group (OR 11.2; 95% CI, 3.4-34.0), or elevated plasma levels of factor VIII (OR 18.6; 95% CI, 7.4-46.9) all relative to patients without these defects, not undergoing orthopedic surgery. CONCLUSIONS: Patients with factor V Leiden, high levels of factor VIII, or blood group non-O were found to have a high risk of VTE after orthopedic surgery. Identification of these patients may enable individualized thromboprophylactic treatment to efficiently reduce VTE risk.

Clinical risk assessment model to predict venous thromboembolism risk after immobilization for lower-limb trauma.

BACKGROUND: Patients with lower-limb trauma requiring immobilization have an increased risk of venous thromboembolism (VTE). While thromboprophylaxis for all patients seems not effective, targeted thromboprophylaxis in high risk patients may be an appropriate alternative. Therefore, we aimed to develop and validate a risk assessment model for VTE risk: the TRiP(cast) score (Thrombosis Risk Prediction following cast immobilization). METHODS: In this prediction model study, for development, data were used from the MEGA study (case-control study into the etiology of VTE) and for validation, data from the POT-CAST trial (randomized trial on the effectiveness of thromboprophylaxis following cast immobilization) were used. Model discrimination was calculated by estimating the Area Under the Curve (AUC). For model calibration, observed and predicted risks were assessed. FINDINGS: The TRiP(cast) score includes 14 items; one item for trauma severity (or type), one for type of immobilization and 12 items related to patients' characteristics. Validation analyses showed an AUC of 0.74 (95%CI 0.61-0.87) in the complete dataset (n = 1250) and 0.72 (95%CI 0.60-0.84) in the imputed data set (n = 1435). The calibration plot shows the degree of agreement between the observed and predicted risks (intercept 0.0016 and slope 0.933). Using a cut-off score of 7 points in the POT-CAST trial (incidence 1.6%), the sensitivity, specificity, positive and negative predictive values were 76.1%, 51.2%, 2.5%, and 99.2%, respectively. INTERPRETATION: The TRiP(cast) score provides a helpful tool in daily clinical practice to accurately stratify patients in high versus low-risk categories in order to guide thromboprophylaxis prescribing. To accommodate implementation in clinical practice a mobile phone application has been developed. FUNDING: ZonMW VIMP grant:17110200011.

Clinical outcomes of postcarotid endarterectomy hypertension.

OBJECTIVE: The objective of this study was to determine the clinical relevance of postcarotid endarterectomy hypertension (PEH) by investigating the effect of PEH on hospital length of stay (LOS) and by investigating short-term and long-term complications of PEH. In addition, risk factors for PEH were determined. METHODS: A single-center retrospective cohort study was performed. Demographic, preoperative, intraoperative, and postoperative outcomes of 192 patients undergoing carotid endarterectomy were evaluated. Outcomes were compared between patients with PEH and patients without PEH. PEH was defined as an acute systolic blood pressure (SBP) rise >170 mm Hg or persistent SBP >150 mm Hg on the ward and leading to the consultation of an internist. The overall survival and event-free survival were compared using a Kaplan-Meier analysis and a Cox regression analysis. A multivariate logistic regression analysis was performed to determine risk factors for PEH. RESULTS: PEH developed in 44 of 192 patients (25%). Preoperative hypertension (SBP >150 mm Hg) was determined to be a risk factor for PEH (odds ratio, 3.3; 95% confidence interval [CI], 1.6-6.9). Hospital LOS was prolonged in patients with PEH compared with patients without PEH (median LOS of 5 days vs 3 days, respectively; P < .001). No difference in the occurrence of ischemic neurologic events or rebleeding during hospitalization was observed (P = .58 and P = .72, respectively). Cardiovascular and ischemic neurologic events during follow-up did not occur more often in patients with PEH than in patients without PEH (P = .46). There was no difference in mortality between the PEH and non-PEH groups (hazard ratio, 1.6; 95% CI, 0.6-4.3). The same applies to the event-free survival (hazard ratio, 0.77; 95% CI, 0.4-1.7). Combined event-free survival for stroke and myocardial infarction was 92% (95% CI, 87%-97%) at 2 years for patients without PEH and 86% (95% CI, 74%-98%) at 2 years for patients with PEH (P = .25). Event-free survival for mortality was 90% (95% CI, 85%-96%) at 2 years for patients without PEH and 94% (95% CI, 86%-100%) at 2 years for patients with PEH (P = .36). CONCLUSIONS: Patients with PEH had a significant increase in hospital LOS. However, adverse short-term and long-term events did not occur more often in patients with PEH. High preoperative SBP was identified as a risk factor for PEH; no other demographic and clinical variables were associated with PEH.

Individualized Thromboprophylaxis in Patients with Lower-Leg Cast Immobilization-A Validation and Subgroup Analysis in the POT-CAST Trial.

BACKGROUND: A small subgroup of patients treated with lower-leg cast immobilization develops venous thromboembolism (VTE). OBJECTIVES: (1) Identify risk factors for VTE in patients with cast immobilization, (2) assess the effectiveness of thromboprophylaxis in low- and high-risk groups, and (3) validate the performance of the L-TRiP(cast) score. METHODS: Data from the POT-CAST trial were used. A total of 1,519 patients with lower-leg cast immobilization were randomized to a prophylactic dose of low-molecular-weight heparin or no treatment. PRIMARY OUTCOME: symptomatic VTE within 3 months. Absolute risks (ARs) were determined for low- and high-risk subgroups. For several risk factors, relative risks (RRs) for VTE were estimated with corresponding 95% confidence intervals (CIs). For validating the L-TRiP(cast) score, a discrimination and calibration analysis were performed. RESULTS: Patients with a body mass index of > 30 kg/m2 and those with a VTE in their family history had an increased VTE risk, RR 3.8 (95% CI, 1.5-9.4) and RR 2.4 (95% CI, 1.0-5.6), respectively. Concerning injury-specific risk factors, patients with an Achilles tendon rupture or those who were surgically treated had the highest risk of VTE, AR at 8.5% (95% CI, 3.7-16.1) and AR 3.5% (95% CI, 1.3-7.5), respectively. There were no subgroups in which thromboprophylaxis was effective for prevention of symptomatic VTE. The area under the curve for the L-TRiP(cast) score was 0.69 (95% CI, 0.58-0.80). CONCLUSION: Thromboprophylaxis was not effective for VTE prevention following lower-leg cast immobilization in any risk category. Low- and high-risk individuals could be identified using the L-TRiP(cast) score. The best treatment strategy for these patients is yet to be determined.