BACKGROUND: Splenectomy (SPLN) is associated with elevated risk of venous thromboembolic (VTE) disease. Enoxaparin (ENX) is a low-molecular-weight heparin agent used in VTE chemoprophylaxis. Early aspirin administration ameliorates postSPLN platelet hyperaggregability in male mice. Previous literature has excluded female mice, citing potential effects of estrogen on platelet count and activation as a reason. We hypothesized that multimodal therapy using aspirin and ENX would mitigate postoperative platelet aggregability in mice across sexes.
METHODS: Murine models of SPLN included both male and female mice. Treatment groups included placebo gavage, sham laparotomy, SPLN alone, SPLN and aspirin, SPLN and ENX, and SPLN with aspirin and ENX (n = 5 per group). Chemoprophylaxis dosing was initiated before SPLN. Mice were euthanized on post-operative day (POD) 1 or 3; platelet counts were obtained and blood samples were analyzed via electrical impedance aggregometry.
RESULTS: Females on POD 3 following SPLN demonstrated increased platelet count compared to female mice with no treatment intervention. Male and female mice demonstrated increased adenosine diphosphate (ADP)-induced platelet aggregability on POD 3 following SPLN compared to the placebo group. Treatment with aspirin and ENX decreased this post-SPLN platelet hyperaggregability in both sexes. Females demonstrated significantly higher ADP-mediated platelet aggregability in placebo, SPLN, and SPLN with aspirin and ENX when compared to males of identical treatment groups on POD 3.
CONCLUSIONS: Platelet hyperaggregability following SPLN is mediated primarily by ADP in both males and females, but higher relative aggregability is demonstrated in females. Early administration of dual-agent VTE chemoprophylaxis utilizing aspirin and ENX mitigates this hyperaggregability and may aid in VTE risk reduction across sexes.

BACKGROUND: Venous thromboembolism (VTE) is a serious, frequent, and preventable medical complication in hospitalized patients. Although the efficacy of prophylaxis (pharmacological and/or mechanical) has been demonstrated, compliance with prophylaxis is poor at international and national levels.
OBJECTIVE: To determine the indication and use of pharmacological thromboprophylaxis in hospitalized patients in Uruguay.
METHODS: An observational, descriptive, cross-sectional, multicentre study involving 31 nationwide healthcare facilities was conducted. Baseline characteristics associated with hospital admission, the percentage of the population with an indication for thromboprophylaxis, and the percentage of patients receiving pharmacological thromboprophylaxis were assessed. The VTE risk was determined using the Padua score for medical patients; the Caprini score for surgical patients; the Royal College of Obstetricians and Gynaecologists (RCOG) guidelines for pregnant-postpartum patients.
RESULTS: 1925 patients were included, representing 26% of hospitalized patients in Uruguay. 71.9% of all patients were at risk of VTE. Of all patients at risk of VTE, 58.6% received pharmacological thromboprophylaxis. The reasons for not receiving thromboprophylaxis were prescribing omissions in 16.1% of cases, contraindication in 15.9% and 9.4% of patients were already anticoagulated for other reasons. Overall, just 68% of patients were \"protected\" against VTE. Recommendations of major thromboprophylaxis guidelines were followed in 70.1% of patients at risk.
CONCLUSIONS: Despite the progress made in adherence to thromboprophylaxis indications, nonadherence remains a problem, affecting one in six patients at risk of VTE in Uruguay.

This article addresses the management of venous thromboembolism in patients with malignant brain tumours, including both primary and secondary (metastatic) tumours. The available data on patients on venous thromboembolism recurrence and bleeding risks in patients with brain tumours is limited, since these patients have been excluded from most randomised, interventional, head-to-head, clinical trials comparing low molecular weight heparins to vitamin K antagonists or to direct oral factor Xa inhibitors. More information is available from retrospective observational studies, which however were generally small, and carried a high risk of confounding. Their findings suggest that direct factor Xa inhibitor use is associated with lower rates of intracranial haemorrhage compared with low molecular weight heparins. Overall, the safety profile of direct oral factor Xa inhibitors when used to prevent venous thromboembolism recurrence in patients with either primary or secondary brain tumours appears to be favourable. The available data are in favour of using an anticoagulant at a full therapeutic dose in patients with primary and secondary brain tumours experiencing a venous thromboembolism, although they are not yet sufficiently robust to permit recommending a direct factor Xa inhibitor over low-molecular weight heparin.

BACKGROUND: The aim of this study was to record and assess the efficacy and safety ofthromboprophylaxis with an intermediate dose of Tinzaparin in lung cancer patients with high thrombotic risk.
METHODS: This was a non-interventional, single-arm, prospective cohort study of lung cancer patients who received thromboprophylaxis with Tinzaparin 10.000 Anti-Xa IU in 0.5 mL, OD, used in current clinical practice. Enrolled ambulatory patients signed informed consent. Anti-Xa levels were tested.
RESULTS: In total, 140 patients were included in the study, of which 81.4% were males. The histology of the tumor was mainly adenocarcinoma. Lung cancer patients with high thrombotic risk based on tumor, patient, treatment, and laboratory-related factors were enrolled. Only one patient experienced a thrombotic event (0.7%), and 10 patients had bleeding events (7.1%), including only one major event. Anti-Xa levels measured at 10 days and 3 months did not differ significantly between patients who developed hemorrhagic events and those who did not (p = 0.26 and p = 0.32, respectively).
CONCLUSIONS: Thromboprophylaxis with an intermediate Tinzaparin dose in high thrombotic-risk lung cancer patients is a safe and effective choice for the prevention of VTE.

Venous thromboembolic disease (VTE) is characterized by obstruction of venous blood flow by a thrombus. Survival data, frequency of disease recurrence, and bleeding rate in patients on anticoagulant therapy with warfarin compared to rivaroxaban in the Latin American population are limited in VTE.
A retrospective cohort study with propensity score matching analysis was conducted in patients with pulmonary embolism and/or deep vein thrombosis anticoagulated with warfarin or rivaroxaban treated. Survival analysis was performed using a Kaplan-Meier curve for each of the intervention groups, and it was compared using a Log Rank test.
Of 2193 potentially eligible patients with a suspected diagnosis of VTE, 505 patients entered the analysis; of these, 285 subjects were managed with warfarin and 220 anticoagulated with rivaroxaban. Major bleeding at 12 months occurred in 2.7% (6/220) of patients treated with Rivaroxaban, compared to 10.2% (29/285) in the Warfarin group in the unmatched population (p = 0.001). In the matched population, bleeding at 12 months occurred in 2.9% (6/209) of patients on Rivaroxaban and in 11.0% (23/209) of patients on Warfarin (p = 0.001). The survival rates at 6 months were 97.1% for Rivaroxaban and 97.6% for Warfarin (p = 0.76). At 12 months, the survival rates were 94.7% for Rivaroxaban and 95.7% for Warfarin (p = 0.61).
In the treatment of VTE, there is no differences on 6 and 12-month survival or a reduction in the occurrence of new thromboembolic events when comparing rivaroxaban to warfarin. However, a lower risk of major bleeding is observed at 12 months with Rivaroxaban.

This article addresses the management of venous thromboembolism in patients with malignant brain tumours, including both primary and secondary (metastatic) tumours. The available data on patients on venous thromboembolism recurrence and bleeding risks in patients with brain tumours is limited, since these patients have been excluded from most randomised, interventional, head-to-head, clinical trials comparing low molecular weight heparins to vitamin K antagonists or to direct oral Factor Xa inhibitors. More information is available from retrospective observational studies, which however were generally small, and carried a high risk of confounding. Their findings suggest that direct Factor Xa inhibitor use is associated with lower rates of intracranial haemorrhage compared with low molecular weight heparins. Overall, the safety profile of direct oral Factor Xa inhibitors when used to prevent venous thromboembolism recurrence in patients with either primary or secondary brain tumours appears to be favourable. The available data are in favour of using an anticoagulant at a full therapeutic dose in patients with primary and secondary brain tumours experiencing a venous thromboembolism, although they are not yet sufficiently robust to permit recommending a direct Factor Xa inhibitor over low-molecular weight heparin.

Thrombosis is one of the leading causes of morbidity and mortality worldwide. Venous thromboembolic disease (VTD) is considered a new epidemic. FXII deficiency is supposed to be a cause of thrombosis. To search for unknown causes of thrombosis in our population, our aim was to determine if FXII deficiency can be considered a risk factor for VTD.
Young adult Mexican patients with at least one VTD episode and healthy controls were included in this prospective, observational, controlled study. Liver and renal function tests, blood cytometry, and blood coagulation assays were performed. Plasma FXII activity and its concentration were evaluated.
Over a two-year period, 250 patients and 250 controls were included. FXII activity was significantly lower in the control group compared to patients with VTD (p = 0.005). However, percentage of patients and controls with FXII deficiency was 8.8 and 9.2%, respectively (p = 1.000). No significant association was found between FXII deficiency and VTD (p = 1.0). FXII plasma concentration was lower in controls vs. patients with VTD: 4.05 vs. 6.19 ng/mL (p <0.001). Percentage of patients with low FXII plasma concentration was 1.6% and 6.0% in patients and controls, respectively (p = 0.010).
FXII deficiency is a frequent finding in patients with VTD and controls in Mexico. Some patients with FXII deficiency had normal APTT result, an effect not described above. FXII plasma concentration was lower in patients with low activity.

OBJECTIVE: Many guidelines indicate that continuous use of anticoagulant drugs reduces the incidence of venous thrombus (VT), but no studies show the effect on the incidence of symptomatic venous thrombus (SVT) in total knee arthroplasty (TKA) patients after discharge. This study aimed to investigate whether it is necessary to apply anticoagulants to TKA patients after discharge.
METHODS: Patients who met the exclusion criteria requirement, underwent TKA by the same surgical team and received anticoagulant therapy after the operation were eligible for the study. Finally, a total of 567 TKA patients were recruited as participants. The patients were divided into two groups. The patients in group A were taken low molecular heparin for 5-10 days after surgery, which included but was not limited to low molecular weight heparin calcium injection (0.4 mL, ih, Qd), calcium dioxin injection (0.6 mL, ih, Qd), or enoxaparin sodium injection (0.4 mL, ih, Qd), and the patients needed to continue oral anticoagulant drug (10 mg, po, Qd) for 7-21 days after discharge. The patients in group B only took low molecular heparin 5-10 days after surgery and no treatment after discharge. The baseline characteristics of patients, total complications of SVT include lower limb vascular pain (LLVP), lower limb vascular pain no fester (LLVPNF), lower limbs swelling (LLS), lower limb fester (LLF), and death by thrombosis (DT), bleeding and mortality following discharged were compared between two groups.
RESULTS: The study showed that the incidence of SVT patients had no significant difference between the two groups (p = 0.489). Moreover, the incidence of LLVP (p = 0.265), LLS (p = 0.84), LLVPNF (p = 0.213), LLF (p = 0.907), DT (p = 0.907), death from other causes, and bleeding (p = 0.323) had no significant differences between the two groups. However, the incidence of SVT in patients with smoking (p = 0.0001 or 0.0011) or drinking (p = 0.0002 or 0.0001) was significantly increased.
CONCLUSIONS: There is not enough evidence showing that the TKA patients given anticoagulants after discharge had benefits in decreasing the risk of SVT. Furthermore, smoking and drinking would significantly increase the risk of SVT in TKA patients.

Portal vein thrombosis (PVT) is a rare disease in children and may be complicated by portal hypertension (PH), hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PPHTN) but their incidence and risk factors are unknown.
An observational, retrospective cohort study of all consecutive children (≤18 years) with PVT treated at the Emma Children\'s Hospital Amsterdam University Medical Centers between January 1996 and January 2022 was conducted to identify the incidence and risk factors of these post thrombotic complications (PTC) in pediatric patients.
In total 43/ 703 thrombosis patients had PVT (boys 72.1 %; mean age 1.3 ± 0.5 years). Overall, 51 % of patients developed PH (n = 22), complicated by PPHTN in one of them. In 16 of 22 patients, PVT presented with portal hypertension. Clinically relevant bleeding due to portal hypertension occurred in 13 (59.1 %) patients with PH. The mean age at the first clinically relevant bleeding was 5.1 ± 5.9 years. Risk factors for the development of PH were lack of complete thrombus resolution (OR 24.3, 95 % CI 1.2-7.0; p = 0.008) and unprovoked VTE (OR, 35.4; 95 % CI 1.4-6.3; p = 0.012). Median time from PVT to PH was 137 days (range: 0 days to 5.04 years).
We demonstrated that half of the patients develop PH after PVT, with a lack of thrombus resolution and unprovoked VTE as independent risk factors. This high incidence underlines the importance of long-term standardized follow-up of patients after PVT and standard screening in patients at risk of PTC.

Direct oral anticoagulants (DOACs) are tending to supplant antivitamin K inhibitors (VKAs) in their common indications, dominated in elderly patients by atrial fibrillation and venous thromboembolism. Nevertheless, it remains necessary to know how best to use VKAs for which there are still indications. It is also important not to assume that AODs can be prescribed without risk, while ignoring certain particularities in their handling, particularly in the most fragile patients with co-morbidities and multiple medications.