Cancer is a known risk factor for venous thromboembolism (VTE). The wider adoption of immunotherapy and anti-angiogenic drugs in recent years have increased this risk further. Central venous catheters (CVCs) are widely used access devices utilized to deliver infusion therapy, mostly in ambulatory settings. The endothelial injury associated with the use of these catheters adds to the risk of VTE to already high-risk patients. The introduction of direct oral anticoagulants (DOACs), with its proven efficacy and safety in multiple clinical indications, have renewed the attention to VTE prophylaxis in cancer patients with CVC. Several clinical trials and meta-analyses had shown that both apixaban and rivaroxaban are effective in lowering the risk of VTE, without increasing the risk of bleeding. Several risk assessment models (RAM) have utilized patient-related, tumor-related, and treatment-related factors, in addition to widely available biomarkers, like Hemoglobin (Hb) level, white blood cell (WBC) and platelets counts to stratify patients into two or three VTE risk levels. In this manuscript, we review the published clinical trials and meta-analyses that attempted to study the efficacy and safety of anticoagulants, mostly the DOACs, in cancer patients with CVCs. We will also propose a practical risk-directed approach to enhance VTE prophylaxis rate.

The differences in the safety and efficacy of anticoagulation between different types of new oral anticoagulants(NOACs) and low molecular weight heparin(LMWH) are still controversial. The main purposes of this study were to analyze safety and efficacy of NOACs versus LMWH for thromboprophylaxis, and perform subgroup analyses stratified by individual NOACs and different populations after total hip arthroplasty (THA) or total knee arthroplasty (TKA). Literature search was performed in PubMed, EMBASE, Cochrane Library, CNKI and Wanfang databases until June 31, 2022. This systematic review and meta-analysis included 46 randomized controlled trials (RCT) with 39, 924 patients. We evaluated the safety and efficacy of thromboprophylaxis between LMWH and NOACs. NOACs were more effective in reducing deep vein thrombosis (DVT) (RR0.59; 95%CI 0.49-0.71) and adverse events (RR: 0.96; 95%CI: 0.93-0.99) than LMWH. The subgroup analyses for different anticoagulants revealed that rivaroxaban (RR:0.49; 95%CI:0.36-0.66), apixaban (RR: 0.54; 95%CI: 0.36-0.81) and edoxaban (RR:0.49; 95%CI: 0.32-0.75) have the lower risk of DVT than LMWH. Apixaban (RR:0.89; 95%CI: 0.80-1.00) had superior prevention of bleeding to LMWH. Edoxaban exhibited a lower risk of VTE (RR: 0.46; 95%CI: 0.33-0.65), advantage events (RR: 0.87; 95%CI: 0.82-0.93), and drug-related adverse events (DRAEs) (RR: 0.64; 95%CI: 0.53-0.76) than LMWH. East Asian population was superior to western population for preventing DVT, advantage events, and DRAE using NOACs. In conclusion, NOACs are more effective than LMWH at preventing DVT and adverse events after arthroplasty. Apixaban has lower bleeding than LMWH, and East Asian populations may benefit more than western population from NOACs.

UNASSIGNED: The guidelines\' recommendations for anticoagulation in cancer patients with catheter-related thrombosis are unclear. The aim of this systematic review was to assess anticoagulation management in cancer patients with catheter-related thrombosis (CRT) based on previously published studies.
UNASSIGNED: As of June 10, 2023,we searched databases including PubMed, Embase, and Cochrane and included 11 observational studies that met the criteria. We evaluated 770 adults with active cancer and objectively confirmed patients with CRT who were using drugs including warfarin, LMWH, and new oral anticoagulants as antithrombotic therapy.
UNASSIGNED: We extracted outcome data, including thrombosis recurrence, catheter dysfunction, major bleeding, and death, and performed a meta-analysis.
UNASSIGNED: In this study we found that the risk of VTE recurrence was higher with rivaroxaban, the risk of bleeding and death appeared to be greater with warfarin, and although the risk of catheter dysfunction due to LMWH is a concern, it is still a more reasonable option for cancer patients with catheter-related thrombosis.
UNASSIGNED: http://www.clinicaltrials.gov, identifier (CRD42022367979).

Hyperkalemia, an elevated blood potassium concentration exceeding 5.0 mEq/L, is associated with adverse outcomes and is frequently observed in hospitalized patients. Drug-induced hyperkalemia accounts for a significant proportion of cases, with heparin, commonly used for venous thrombosis prevention, suspected to contribute, though less recognized than other heparin-related side effects. Both unfractionated heparin (UFH) and low molecular weight heparin (LMWH) have been implicated in inducing hyperkalemia, primarily through the suppression of aldosterone levels and modulation of angiotensin II receptors. This systematic review examines the relationship between heparin, particularly LMWH, and hyperkalemia. Thirteen studies involving 1407 patients were analyzed. Findings indicated a lack of highquality evidence, with no significant increase in potassium levels associated with LMWH use. LMWH did not exhibit a dose-response relationship with hyperkalemia incidence. Additionally, mechanisms underlying the hypothetical LMWHinduced hyperkalemia remained inconclusive. While this suggests that LMWH is unlikely to be a primary cause of hyperkalemia, caution is warranted, especially in patients with elevated baseline potassium levels.

UNASSIGNED: To date, the available guidance on venous thromboembolism (VTE) prevention in elective lumbar fusion surgery is largely open to surgeon interpretation and preference without any specific suggested chemoprophylactic regimen.
UNASSIGNED: This study aimed to comparatively analyze the incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE) with the use of commonly employed chemoprophylactic agents such as unfractionated heparin (UH) and low molecular weight heparin (LMWH) in lumbar fusion surgery.
UNASSIGNED: An independent systematic review of four scientific databases (PubMed, Scopus, clinicaltrials.gov, Web of Science) was performed to identify relevant articles as per the preferred reporting in systematic reviews and meta-analysis (PRISMA) guidelines. Studies reporting on DVT/PE outcomes of lumbar fusion surgery in adult patients with UH or LMWH chemoprophylaxis were included for analysis. Analysis was performed using the Stata software.
UNASSIGNED: Twelve studies with 8495 patients were included in the analysis. A single-arm meta-analysis of the included studies found a DVT incidence of 14% (95%CI [8%-20%]) and 1% (95%CI [-6% - 8%]) with LMWH and UH respectively. Both the chemoprophylaxis agents prevented PE with a noted incidence of 0% (95%CI [0%-0.1%]) and 0% (95%CI [0%-1%]) with LMWH and UH respectively. The risk of bleeding-related complications with the usage of LMWH and UH was 0% (95% CI [0.0%-0.30%]) and 3% (95% CI [0.3%-5%]) respectively.
UNASSIGNED: Both LMWH and UH reduces the overall incidence of DVT/PE, but there is a paucity of evidence analyzing the comparative effectiveness of the chemoprophylaxis regimens in lumbar fusion procedures. The heterogeneity in data prevents any conclusions, as there remains an evidence gap. We recommend future high-quality randomized controlled trials to investigate in this regard to help develop recommendations on thromboprophylaxis usage.

Heparin and derivatives are commonly used for thrombophylaxis in surgical colorectal cancer (CRC) patients. Recent studies have suggested that, besides its protective effect on the incidence of venous thromboembolism, heparin has an anti-cancer effect. The aim of this review was to explore the literature and report the antineoplastic effect of heparin and derivatives on CRC. MEDLINE and EMBASE databases were searched for relevant articles. Nineteen studies were included (n = 19). Fifteen were lab studies conducted in vivo or in vitro on CRC cell lines and/or mice (n = 15). Four were in vivo clinical studies (n = 4). CRC tumor growth was reduced by 78% in one study, (p < 0.01), while tumorigenesis was suppressed in heparin-treated mice in seven studies. A high dose of low molecular weight heparin for extended duration significantly reduced post-operative VEGF, suggesting that such a regime may inhibit tumor angiogenesis and distant metastasis. A randomized trial demonstrated the antineoplastic effect of nadroparin as the 6 month survival in palliative patients increased. Another study has reported that disease-free survival of CRC patients was not affected by a similar tinzaparin regime. The anti-cancer properties of heparin and derivatives are promising, especially in lab studies. Further clinical trials are needed to investigate the anti-cancer benefit of heparin on CRC.

The commonest cause of microvascular free flap failure is thrombosis at the anastomosis. Pharmacological antithrombotic therapies have been used to mitigate this risk, but they carry the risk of bleeding and haematoma formation. To justify any intervention, it is necessary to evaluate the benefits and balance of risks. This meta-analysis aims to quantify the value of systemic anticoagulation during head and neck free tissue reconstruction. We performed a systematic review on the impact of additional prophylactic antithrombotic therapy on head and neck (H&N) free tissue transfer (on top and above the use of low molecular weight heparin to prevent deep vein thrombosis). We carried a PRISMA-guided literature review, following registration with PROSPERO. All studies analysing the possible impact of prophylactic anticoagulants on free flap surgery in the head and neck were eligible. The primary outcome was perioperative free flap complications (perioperative thrombosis, partial or total free flap failure, thrombo-embolic events, or re-exploration of anastomosis). Secondary outcomes included haematoma formation or bleeding complications requiring further intervention. We identified eight eligible studies out of 454. These included 3531 free flaps for H&N reconstruction. None of the assessed interventions demonstrated a statistically significant improvement in free flap outcomes. Accumulative analysis of all anti-coagulated groups demonstrated an increased relative risk of free flap complications [RR 1.54 (0.73-3.23)] compared to control albeit not statistically significant (p = 0.25). Pooled analysis from the included studies showed that the prophylactic use of therapeutic doses of anticoagulants significantly (p = 0.003) increased the risk of haematoma and bleeding requiring intervention [RR 2.98 (1.47-6.07)], without reducing the risk of free flap failure. Additional anticoagulation does not reduce the incidence of free flap thrombosis and failure. Unfractionated heparin (UFH) consistently increased the risk of free flap complications. The use of additional anticoagulation as \'prophylaxis\' in the perioperative setting, increases the risk of haematoma and bleeding.

Venous thromboembolism (VTE) causes significant morbidity and mortality in patients with traumatic injuries, despite thromboprophylaxis. To decrease both thrombotic and bleeding risks, some authors suggest adjusting the thromboprophylactic doses of low-molecular-weight heparins (LMWH), in particular according to body weight at treatment initiation or to changes in anti-factor Xa level during treatment. Our objective was to estimate in trauma patients the efficacy and safety of such adjustments, compared with the conventional strategy of fixed-dose LMWH thromboprophylaxis.
A systematic review and a meta-analysis were conducted to identify and assess randomised control trials and observational studies with prospective enrolment that included trauma patients and compared adjustment of LMWH thromboprophylaxis versus no adjustment. The primary and secondary endpoints were VTE and bleeding, respectively. The Odds Ratio (OR) and 95% Confidence Interval (95% CI) were calculated using the Mantel-Haenszel method.
Nine studies were included in the meta-analysis. No significant reduction in the risk of VTE was observed with adjusted doses of LMWH compared with fixed doses when considering only randomised control trials (OR 1.02 [95% CI, 0.09 to 11.6]) or all trials (OR 0.70 [95% CI, 0.34 to 1.42]). Similarly, there was no significant difference in bleeding risk (OR 1.36, 95% CI 0.59 to 3.10).
This meta-analysis shows that, to date, there is no evidence to justify adjusting LMWH doses, in agreement with the recommendations of the American College of Chest Physicians.

BACKGROUND: The introduction of direct oral anticoagulants (DOACs) shows promise for their role as a chemoprophylaxis agent post-total knee arthroplasty (TKA) for the prevention of venous thromboembolism (VTE). However, existing studies are largely based on Western populations that do not account for the different risk profiles and lower rates of VTE in Asians. This systematic review and meta-analysis aimed to evaluate the efficacy of DOACs compared to enoxaparin in an Asian-based population study.
METHODS: The review was conducted in accordance with PRISMA guidelines. All studies that compared outcomes between enoxaparin and DOACs as VTE prophylaxis post-TKA in the Asian population were included.
RESULTS: Five studies with 121,153 patients were included. DOACs demonstrated a convincing benefit over enoxaparin in overall VTE prevention (OR=0.42, 95%CI: 0.24-0.74). However, while the OR trended in favour of DOACs for the reduction of DVT events (OR=0.54, 95%CI:0.20-1.48) and pulmonary embolism (PE) (OR=0.75, 95%CI:0.07-8.20) statistical significance was not reached. In terms of bleeding complications, both arms had similar rates of major (0.91% vs. 0.20%), clinically relevant non-major (CRNM) (3.28% vs. 2.94%) and minor bleeding complications (12.8 vs. 13.3%). A non-significance advantage of enoxaparin over DOACs was revealed in the OR for major bleeding (OR=3.17; 95%CI: 0.81-12.43), while DOACs were favoured to reduce risk of CRNM (OR =0.82; 95%CI: 0.01-91.51) and minor bleeding (OR=0.76; 95%CI: 0.11-5.33).
CONCLUSIONS: DOACs confer a significantly reduced rate of overall VTE compared to enoxaparin in Asians post-TKA. No significant differences in DVT, PE and rates of bleeding complications exist.

Background: Antithrombotic treatment, including low molecular weight heparin (LMWH) or unfractionated heparin (UFH), has been proposed as a potential therapy for coronavirus disease 2019 (COVID-19) to lower diffuse intravascular clotting activation. However, it is unclear whether prophylactic or therapeutic doses have similar efficacy in reducing mortality. Methods: We performed a systematic review (PROSPERO registration CRD42020179955) and meta-analysis including observational cohort studies and randomized controlled trials (RCT) evaluating the effectiveness of heparins (either LMWH, UFH, or fondaparinux) in COVID-19 patients. Heparin treatment was compared to no anticoagulation. A subgroup analysis on prophylactic or therapeutic doses compared to no anticoagulation was performed. Prophylactic dose was also compared to full dose anticoagulation. Primary endpoint was all-cause mortality. Secondary endpoints were major bleeding and length of hospital stay (LOS). Results: 33 studies (31 observational, 2 RCT) were included for a total overall population of 32,688 patients. Of these, 21,723 (66.5%) were on heparins. 31 studies reported data on all-cause mortality, showing that both prophylactic and full dose reduced mortality (pooled Hazard Ratio [HR] 0.63, 95% confidence interval [CI] 0.57-0.69 and HR 0.56, 95% CI 0.47-0.66, respectively). However, the full dose was associated with a higher risk of major bleeding (Odds Ratio [OR] 2.01, 95% CI 1.14-3.53) compared to prophylactic dose. Finally, LOS was evaluated in 3 studies; no difference was observed between patients with and without heparins (0.98, -3.87, 5.83 days). Conclusion: Heparin at both full and prophylactic dose is effective in reducing mortality in hospitalized COVID-19 patients, compared to no treatment. However, full dose was associated with an increased risk of bleeding. Systematic Review Registration: https://clinicaltrials.gov/, identifier CRD42020179955.