Comparison of Bivalirudin Versus Heparin for Maintenance Systemic Anticoagulation During Adult and Pediatric Extracorporeal Membrane Oxygenation.

OBJECTIVES: To provide a comparative analysis of conventional heparin-versus bivalirudin-based systemic anticoagulation in adult and pediatric patients supported on extracorporeal membrane oxygenation. DESIGN: Retrospective chart review study of adult and pediatric patients receiving extracorporeal membrane oxygenation from January 1, 2014, to October 1, 2019. SETTING: A large, high-volume tertiary referral adult and pediatric extracorporeal membrane oxygenation center. PATIENTS: Four hundred twenty-four individuals requiring extracorporeal membrane oxygenation support and systemically anticoagulated with either unfractionated heparin (223 adult and 65 pediatric patients) or bivalirudin (110 adult and 24 pediatric patients) were included. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Digital data abstraction was used to retrospectively collect patient details. The majority of both groups were cannulated centrally (67%), and the extracorporeal membrane oxygenation type was predominantly venoarterial (84%). The adult bivalirudin group had a greater occurrence of heparin-induced thrombocytopenia (12% vs 1%; p < 0.01) and was more likely to require postcardiotomy extracorporeal membrane oxygenation (36% vs 55%; p < 0.01). There were no statistical differences between the groups in regards to age, sex, and extracorporeal membrane oxygenation initiation location. The main finding was a reduced mortality in the adult bivalirudin group (odds ratio, 0.39; p < 0.01), whereas no difference was noted in the pediatric group. A significant reduction in the composite transfusion requirement in the first 24 hours was noted in the pediatric bivaluridin group with an odds ratio of 0.28 (p = 0.02). Groups did not differ in regard to laboratories per day, anticoagulant dose adjustments, or ischemic complications. CONCLUSIONS: When compared with heparin-based systemic anticoagulation, bivalirudin demonstrated feasibility and safety as established by the absence of increases in identifiable adverse outcomes while manifesting substantial improvements in hospital mortality in adult patients. Further studies are necessary to corroborate these findings and further elucidate the role of bivalirudin during extracorporeal membrane oxygenation support.

Thrombotic complications with interruption of direct oral anticoagulants in dermatologic surgery.

BACKGROUND: Direct oral anticoagulants (DOACs), such as apixaban, rivaroxaban, and dabigatran, are increasingly being used to provide prophylaxis and treatment for arterial and venous thromboembolism. Multiple procedural subspecialties have implemented guidelines detailing time frames for perioperative DOAC interruption; however, the impact of perioperative DOAC interruption in patients undergoing dermatologic surgery is currently unknown, and evidence-based guidelines are lacking. OBJECTIVE: To assess the 30-day postoperative rate of thrombotic complications (ischemic stroke, transient ischemic attack, systemic embolism, deep vein thrombosis [DVT] and pulmonary embolism) in patients with nonvalvular atrial fibrillation (AF) or a history of DVT who underwent perioperative DOAC interruption during dermatologic surgery. METHODS: A retrospective medical record review was performed of all patients with AF or a history of DVT who underwent perioperative DOAC interruption during dermatologic surgery at Advanced Dermatologic Surgery and the University of Kansas Medical Center between January 1, 2016, and August 31, 2020. RESULTS: Among 806 operations, comprising 750 Mohs micrographic operations (93.1%) and 56 excisions (6.9%), 1 patient (0.14% of patients with AF) sustained a transient ischemic attack and 2 patients (0.25% of all patients) sustained minor bleeding complications during the 30-day postoperative period. CONCLUSION: Perioperative DOAC interruption appears to be safe and efficacious in dermatologic surgery.

Anti-Xa activity and hemorrhagic events under extracorporeal membrane oxygenation (ECMO): a multicenter cohort study.

BACKGROUND: Hemorrhagic events remain a major concern in patients under extracorporeal membrane oxygenation (ECMO) support. We tested the association between anticoagulation levels and hemorrhagic events under ECMO using anti-Xa activity monitoring. METHODS: We performed a retrospective multicenter cohort study in three ECMO centers. All adult patients treated with veno-venous (VV)- or veno-arterial (VA)-ECMO in 6 intensive care units between September 2017 and August 2019 were included. Anti-Xa activities were collected until a hemorrhagic event in the bleeding group and for the duration of ECMO in the non-bleeding group. All dosages were averaged to obtain means of anti-Xa activity for each patient, and patients were compared according to the occurrence or not of bleeding. RESULTS: Among 367 patients assessed for eligibility, 121 were included. Thirty-five (29%) presented a hemorrhagic complication. In univariate analysis, anti-Xa activities were significantly higher in the bleeding group than in the non-bleeding group, both for the mean anti-Xa activity (0.38 [0.29-0.67] vs 0.33 [0.22-0.42] IU/mL; p = 0.01) and the maximal anti-Xa activity (0.83 [0.47-1.46] vs 0.66 [0.36-0.91] IU/mL; p = 0.05). In the Cox proportional hazard model, mean anti-Xa activity was associated with bleeding (p = 0.0001). By Kaplan-Meier analysis with the cutoff value at 0.46 IU/mL obtained by ROC curve analysis, the probability of survival under ECMO without bleeding was significantly lower when mean anti-Xa was > 0.46 IU/mL (p = 0.0006). CONCLUSION: In critically ill patients under ECMO, mean anti-Xa activity was an independent risk factor for hemorrhagic complications. Anticoagulation targets could be revised downward in both VV- and VA-ECMO.

Evaluating Effectiveness and Safety in Chronic Kidney Disease with Atrial Flutter Using an Anticoagulation Strategy.

Background and Objectives: Recent randomized trials of oral antithrombotic drugs with atrial flutter (AFL) excluded patients with renal impairment because of their increased risk of bleeding. To date, no relevant studies have assessed the effectiveness and safety of different antithrombotic drugs in chronic kidney disease (CKD) patients with AFL. This cohort study evaluated the effectiveness and safety of different antithrombotic drugs in CKD patients with AFL. This study also investigated the risk of cardiovascular events from antithrombotic drugs through different risk profiles of stroke stratified by the CHA2DS2-VASc score. Materials and Methods: This cohort study was performed in patients with AFL and CKD who were extracted from the National Health Insurance (NHI) Database in Taiwan. Oral antithrombotic therapy (oral anticoagulants (OAC) or antiplatelets (APT)) was administered to patients who had been diagnosed with AFL after being diagnosed with CKD between 2011 and 2015. Primary outcomes, including ischemic stroke, systemic embolism, and composite of stroke, and secondary outcomes, including major adverse cardiac events (MACEs), major bleeding, all-cause mortality, and cardiovascular-related death, were examined. Results: A total of 2468 patients were included in this study. The results showed no statistically significant differences in the risk of primary outcomes. For the secondary outcomes, there were also no statistically significant differences in the risk of MACEs and major bleeding. However, the pooled results indicated that the hazard ratio (HR) for all-cause mortality with OAC was 0.24 (95% confidence interval (CI) = 0.10-0.55) compared with combination therapy, and the HR for APT compared with OAC was 2.86 (95% CI = 1.48-5.53). Conclusions: In the studied population, OAC or APT alone were proved equally effective for stroke prophylaxis. Furthermore, OAC might reduce the all-cause mortality rate compared with APT and should be considered as the first choice of oral antithrombotic drugs in patients with AFL and CKD.

Biosimilars of low molecular weight heparins: Relevant background information for your drug formulary.

Biosimilars of low molecular weight heparins (LMWHs) are more alike the originator than different branded LMWHs. The latter differ largely in molecular weight, anti-FXa/anti-FIIa ratio and antithrombin binding. The Food and Drug Administration and European Medicines Agency guidelines are sufficient for the clinical use of high quality LMWHs. However, the Food and Drug Administration guideline lacks the results of a phase I clinical trial in the approval process. Most information about biosimilars is available for enoxaparin given that many biosimilars of enoxaparin have received market access. The guidelines of many International Thrombosis Societies for LMWH biosimilars are too stringent, not updated and impractical for formulary uptake discussions. This review gives background information on critical factors for the formulary uptake process of LMWHs with special attention for the use of the System of Objectified Judgment Analysis/Infomatrix model.

Physicians' Perceptions of Their Patients' Attitude and Knowledge of Long-Term Oral Anticoagulant Therapy in Bulgaria.

Background and Objectives: Oral anticoagulation (OAC) is widely used in daily clinical practice worldwide for various indications. We aimed to explore the perception of Bulgarian clinicians about their patients' attitude and knowledge of long-term OAC, prescribed for atrial fibrillation (AF) and/or known deep venous thrombosis (DVT)/pulmonary embolism (PE). Materials and Methods: We performed a cross-sectional study that involved 226 specialists: 187 (82.7%) cardiologists, 23 (10.2%) neurologists, and 16 (7.1%) vascular surgeons. They filled in a questionnaire, specially designed for our study, answering various questions regarding OAC treatment in their daily clinical practice. Results: The mean prescription rate of OACs in AF patients was 80.3% and in DVT/PE-88.6%. One hundred and eighty-seven (82.7%) of the participants stated they see their patients on OAC at least once per month. According to more than one-third of the inquired clinicians, the patients did not understand well enough the provided information concerning net clinical benefit of OAC treatment. About 68% of the clinicians declared that their patients would prefer a "mutual" approach, discussing with the physician the OAC options and taking together the final decision, whereas according to 43 (19.0%), the patients preferred the physician to take a decision for them. Patients' OAC treatment had been interrupted at least once within the last year due to a physician's decision by 178 (78.8%) of the participants and the most common reason was elective surgery. The most influential factors for a patient's choice of OAC were the need of a specific diet to be kept, intake frequency, and possible adverse reactions. Conclusions: Our results suggest that a clinician's continuous medical education, shared decision-making, and appropriate local strategies for improved awareness of AF/DVT/PE patients are key factors for improvement of OAC management.

Dried-Blood-Spot Technique to Monitor Direct Oral Anticoagulants: Clinical Validation of a UPLC-MS/MS-Based Assay.

Plasma concentrations of direct oral anticoagulants (DOACs) vary largely between individuals, and they correlate well with desired and adverse outcomes. Although regular concentration monitoring of DOACs is not recommended, information on DOAC exposure could be useful in situations when multiple DOAC-clearance pathways are impaired or nonadherence is suspected. Self-sampling techniques, like the use of dried-blood spots (DBSs), would be particularly useful because they enable the collection of information in ambulatory patients at relevant points in time of the dosing interval (e.g., trough). We developed and validated a DBS-based assay to quantify all currently marketed DOACs (apixaban, dabigatran, edoxaban, and rivaroxaban) in a single ultraperformance-liquid-chromatography-tandem-mass-spectrometry assay. It fulfilled all validation standards within a hematocrit range of 0.33-0.65 and was linear over the calibration ranges of 2.5-750 ng/mL (apixaban and rivaroxaban), 4.4-750 ng/mL (dabigatran), and 9.3-750 ng/mL (edoxaban). Only minor ion suppression (matrix effect ≤13%) was present, inter- and intra-assay precision was ≤13%, and inter- and intra-assay accuracies ranged between 88 and 110%. All DOACs were stable in DBSs up to 52 days at room temperature, if the DBSs were protected from light and humidity. The correlation between (whole blood) DBS and plasma concentrations was assessed in 33 patients under regular DOAC therapy. Deming-regression coefficients between simultaneously collected capillary DBSs and plasma samples were used to predict plasma concentrations from DBSs. Bland-Altman plots revealed a strong agreement between predicted and observed plasma concentrations, thus confirming the suitability of DBSs for DOAC monitoring as an important step toward the important aim of self-sampling at home.

Management of Coagulation and Anticoagulation in Liver Transplantation Candidates.

Hemostasis is a complex balance of clot formation and dissolution that is largely modulated by protein synthesis and degradation in the liver. In the state of end-stage liver disease, there is a disruption of the hemostatic system due to hepatic protein synthetic dysfunction. Because historical clinical laboratory testing often only analyzes a portion of the hemostasis system, the clinician may be misled into believing that cirrhosis patients are imbalanced with a tendency toward bleeding. The modern understanding of hemostasis in cirrhosis involves a rebalance of hemostasis with a tenuous equilibrium between clotting and bleeding, but an equilibrium nonetheless. The clinician should be aware of this rebalance and not depend on limited and flawed laboratory testing in making judgments about the tendency for bleeding or clotting based on these values alone. Prophylactic protocol transfusions including large doses of fresh frozen plasma to "correct" the international normalized ratio are good examples of ineffective and potentially harmful interventions based on an outdated understanding of hemostasis in cirrhosis. Conversely, a thrombotic state is increasingly recognized in patients with cirrhosis, and conditions such as portal vein thrombosis are now becoming important therapeutic targets in many liver transplantation (LT) candidates and other patients with chronic liver disease. This article will introduce the reader to the modern understanding of hemostasis in cirrhosis, describe the common pitfalls and opportunities in treating hemostasis system abnormalities in the LT candidate particularly in regards to preprocedural prophylactic transfusions, and discuss therapeutic targets and interventions for thrombotic complications in the end-stage liver disease population.

Extended Venous Thromboembolism Prophylaxis after Radical Cystectomy: A Call for Adherence to Current Guidelines.

PURPOSE: Radical cystectomy is inherently associated with morbidity. We assess the timing and incidence of venous thromboembolism, review current guideline recommendations and provide evidence for considering extended venous thromboembolism prophylaxis in all patients undergoing radical cystectomy. MATERIALS AND METHODS: We searched PubMed® for available literature on radical cystectomy and venous thromboembolism, focusing on incidence and timing, evidence supporting extended venous thromboembolism prophylaxis in patients undergoing radical cystectomy or abdominal oncologic surgery, current guideline recommendations, safety considerations and direct oral anticoagulants. Search terms included "radical cystectomy," "venous thromboembolism," "prophylaxis," and "extended oral anticoagulants" and "direct oral anticoagulants" alone and in combination. Relevant articles were reviewed, including original research, reviews and clinical guidelines. References from review articles and guidelines were also assessed to develop a narrative review. RESULTS: The incidence of symptomatic venous thromboembolism in short-term followup after radical cystectomy is 3% to 11.6%, of which more than 50% of cases will occur after hospital discharge. Meta-analyses of clinical trials in patients undergoing major abdominal oncologic operations suggest a decreased risk of venous thromboembolisms for patients receiving extended (4 weeks) venous thromboembolism prophylaxis. Extended prophylaxis should be considered in all radical cystectomy cases. Although the relative risk of bleeding also increases, the overall net benefit of extended prophylaxis clearly favors use for at least 28 days postoperatively. Extrarenal eliminated prophylaxis agents are preferred given the risk of renal insufficiency in radical cystectomy cases, with newer oral anticoagulants providing an alternative route of administration. CONCLUSIONS: Patients undergoing radical cystectomy are at high risk for venous thromboembolism after hospital discharge. There is strong evidence that extended prophylaxis significantly decreases the risk of venous thromboembolism in oncologic surgery cases. Use of extended prophylaxis after radical cystectomy has been poorly adopted, emphasizing the need for better adherence to current urology procedure specific guidelines as extended prophylaxis for radical cystectomy is the standard of care. Specific and rare circumstances may require case by case assessment.

Use of Direct Oral Anticoagulants for Treating Venous Thromboembolism in Patients With Cancer.

For patients with cancer who experience venous thromboembolism (VTE), low-molecular-weight heparin (LMWH) remains the standard of care in the NCCN Guidelines for VTE, but under certain conditions direct oral anticoagulants (DOACs) are acceptable alternatives. A growing body of literature suggests that DOACs may more effective than LMWHs in preventing recurrences, but they do carry some increased risk of bleeding. Most of this risk is seen in patients with gastrointestinal or urinary pathology or implanted devices. DOACs are also acceptable when the pain, cost, and inconvenience of LMWHs are expected to be obstacles to compliance. Through careful patient selection, most patients can be treated successfully with a DOAC, although for most patients with gastrointestinal or urinary pathology, LMWH remains the safer choice.

The Society of Thoracic Surgeons, The Society of Cardiovascular Anesthesiologists, and The American Society of ExtraCorporeal Technology: Clinical Practice Guidelines-Anticoagulation During Cardiopulmonary Bypass.

Despite more than a half century of "safe" cardiopulmonary bypass (CPB), the evidence base surrounding the conduct of anticoagulation therapy for CPB has not been organized into a succinct guideline. For this and other reasons, there is enormous practice variability relating to the use and dosing of heparin, monitoring heparin anticoagulation, reversal of anticoagulation, and the use of alternative anticoagulants. To address this and other gaps, The Society of Thoracic Surgeons, the Society of Cardiovascular Anesthesiologists, and the American Society of Extracorporeal Technology developed an Evidence Based Workgroup. This was a group of interdisciplinary professionals gathered to summarize the evidence and create practice recommendations for various aspects of CPB. To date, anticoagulation practices in CPB have not been standardized in accordance with the evidence base. This clinical practice guideline was written with the intent to fill the evidence gap and to establish best practices in anticoagulation therapy for CPB using the available evidence. To identify relevant evidence, a systematic review was outlined and literature searches were conducted in PubMed using standardized medical subject heading (MeSH) terms from the National Library of Medicine list of search terms. Search dates were inclusive of January 2000 to December 2015. The search yielded 833 abstracts, which were reviewed by two independent reviewers. Once accepted into the full manuscript review stage, two members of the writing group evaluated each of 286 full papers for inclusion eligibility into the guideline document. Ninety-six manuscripts were included in the final review. In addition, 17 manuscripts published before 2000 were included to provide method, context, or additional supporting evidence for the recommendations as these papers were considered sentinel publications. Members of the writing group wrote and developed recommendations based on review of the articles obtained and achieved more than two thirds agreement on each recommendation. The quality of information for a given recommendation allowed assessment of the level of evidence as recommended by the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Recommendations were written in the three following areas: (1) heparin dosing and monitoring for initiation and maintenance of CPB; (2) heparin contraindications and heparin alternatives; and (3) reversal of anticoagulation during cardiac operations. It is hoped that this guideline will serve as a resource and will stimulate investigators to conduct more research and to expand on the evidence base on the topic of anticoagulation therapy for CPB.

Prevention of perioperative venous thromboembolism in pediatric patients: Guidelines from the Association of Paediatric Anaesthetists of Great Britain and Ireland (APAGBI).

The Association of Paediatric Anaesthetists of Great Britain and Ireland (APAGBI) Guidelines Working Group on Thromboprophylaxis in Children has reviewed the literature and where possible provided advice on the care of children in the perioperative period. Areas reviewed include the incidence of perioperative venous thromboembolism (VTE), risk factors, evidence for mechanical and chemical prophylaxis, and complications. Safe practice of regional anesthesia with anticoagulant prophylaxis is detailed. In summary, there are few areas of strong evidence. Routine prophylaxis cannot be recommended for young children. Postpubertal adolescents (approximately 13 years and over) are at a slightly increased risk of VTE and should be assessed for prophylaxis and may warrant intervention if other risk factors are present. However, the incidence of VTE is significantly lower than in the adult population. This special interest review presents a summary and discussion of the key recommendations, a decision-making algorithm and a risk assessment chart. For the full guideline, go to www.apagbi.org.uk/publications/apa-guidelines.

European guidelines on perioperative venous thromboembolism prophylaxis: Surgery during pregnancy and the immediate postpartum period.

: Thromboembolic events in the pregnant and postpartum patient remain rare but potentially fatal complications. The aim of this section was to analyse the few prospective studies addressing the issue of thromboprophylaxis following a surgical procedure during and immediately after pregnancy, as well as national guidelines, and to propose European guidelines on this specific condition. Thromboprophylaxis is broadly recommended due to the combined risks of surgery and pregnancy or the postpartum period, regardless of the mode of delivery. We recommend prophylactic thromboprophylaxis following surgery during pregnancy or the postpartum period when they imply, as a consequence, bed rest, until full mobility is recovered (Grade 1C). Similarly, thromboprophylaxis should be used in cases of perioperative infection during pregnancy or the postpartum period. Concerning thromboprophylaxis following a caesarean section, it seems avoidable only in elective procedures in low-risk patients, after a normal pregnancy, and with an early rehabilitation protocol. The duration of thromboprophylaxis following caesarean section should be at least 6 weeks for high-risk patients, and at least 7 days for the other patients requiring anticoagulation (Grade 1C).

European guidelines on perioperative venous thromboembolism prophylaxis: Surgery in the elderly.

: The risk for postoperative venous thromboembolism (VTE) is increased in patients aged more than 70 years and in elderly patients presenting with co-morbidities, for example cardiovascular disorders, malignancy or renal insufficiency. Therefore, risk stratification, correction of modifiable risks and sustained perioperative thromboprophylaxis are essential in this patient population. Timing and dosing of pharmacoprophylaxis may be adopted from the non-aged population. Direct oral anti-coagulants are effective and well tolerated in the elderly; statins may not replace pharmacological thromboprophylaxis. Early mobilisation and use of non-pharmacological means of thromboprophylaxis should be exploited. In elderly patients, we suggest identification of co-morbidities increasing the risk for VTE (e.g. congestive heart failure, pulmonary circulation disorder, renal failure, lymphoma, metastatic cancer, obesity, arthritis, post-menopausal oestrogen therapy) and correction if present (e.g. anaemia, coagulopathy) (Grade 2C). We suggest against bilateral knee replacement in elderly and frail patients (Grade 2C). We suggest timing and dosing of pharmacological VTE prophylaxis as in the non-aged population (Grade 2C). In elderly patients with renal failure, low-dose unfractionated heparin (UFH) may be used or weight-adjusted dosing of low molecular weight heparin (Grade 2C). In the elderly, we recommend careful prescription of postoperative VTE prophylaxis and early postoperative mobilisation (Grade 1C). We recommend multi-faceted interventions for VTE prophylaxis in elderly and frail patients, including pneumatic compression devices, low molecular weight heparin (and/or direct oral anti-coagulants after knee or hip replacement) (Grade 1C). : This article is part of the European guidelines on perioperative venous thromboembolism prophylaxis. For details concerning background, methods, and members of the ESA VTE Guidelines Task Force, please, refer to:Samama CM, Afshari A, for the ESA VTE Guidelines Task Force. European guidelines on perioperative venous thromboembolism prophylaxis. Eur J Anaesthesiol 2018; 35:73-76.A synopsis of all recommendations can be found in the following accompanying article: Afshari A, Ageno W, Ahmed A, et al., for the ESA VTE Guidelines Task Force. European Guidelines on perioperative venous thromboembolism prophylaxis. Executive summary. Eur J Anaesthesiol 2018; 35:77-83.

European guidelines on perioperative venous thromboembolism prophylaxis: Day surgery and fast-track surgery.

: In recent years, day surgery and fast-track surgery have experienced a continuous increase in volume. Many procedures are now performed on an outpatient protocol, including general, orthopaedic, oncological, reconstructive or vascular surgery. The management of these patients is safe, but the incidence of venous thromboembolism in this population remains unknown. Several risk factors can be identified and stratified derived from studies of inpatient surgical management (e.g. Caprini score). Recommendations for thromboprophylaxis should be tailored from the assessment of both personal and procedure-related risk factors, although with a lack of evidence for application in outpatient management. For patients undergoing a low-risk procedure without additional risk factors, we recommend only general measures of thromboprophylaxis (early ambulation, optimal hydration) (Grade 1B). For patients undergoing a low-risk procedure with additional risk factors, or a high-risk procedure without additional risk factors, we recommend general measures of thromboprophylaxis (Grade 1B) and we suggest the administration of pharmacological prophylaxis with low molecular weight heparins (Grade 2B). For patients undergoing a high-risk procedure with additional risk factors we recommend general measures of thromboprophylaxis (Grade 1B) and pharmacological prophylaxis with low molecular weight heparins over other drugs (Grade 1B), or suggest specific mechanical measures in case of increased bleeding risk (Grade 2C). Pharmacological prophylaxis should last a minimum of 7 days (Grade 1B), although in selected cases of fast-track surgery, thromboprophylaxis could be limited to hospitalisation only (Grade 2C) and in specific cases of high-risk procedures, thromboprophylaxis could be extended for up to 4 weeks (Grade 2B).

European guidelines on perioperative venous thromboembolism prophylaxis: Surgery in the obese patient.

: A systematic literature search was performed and patients were selected as obese patients undergoing bariatric surgery or obese patients undergoing nonbariatric surgical procedures. In addition, patients were stratified according to low risk of venous thromboembolism and high risk of venous thromboembolism (age >55 years, BMI >55 kg m, history of venous thromboembolism, venous disease, sleep apnoea, hypercoagulability or pulmonary hypertension). Prophylaxis of venous thromboembolism was analysed depending on the type of modality: compression devices of the lower extremities (including intermittent pneumatic compression and graduated compression stockings), pharmacological prophylaxis or inferior vena cava filters. Two prospective studies compared mechanical devices and pharmacological prophylaxis vs. a mechanical device alone without significant differences. A few randomised controlled studies and most of the prospective nonrandomised studies showed that low-dose low molecular weight heparin (3000 to 4000 anti-Xa IU 12 h subcutaneously) was acceptable for obese patients with a lower risk of venous thromboembolism, but a higher dose of low molecular weight heparin (4000 to 6000 anti-Xa IU 12 h subcutaneously) should be proposed for obese patients with a higher risk of venous thromboembolism. Extended prophylaxis for 10 to 15 days was well tolerated for obese patients with a high risk of venous thromboembolism in the postdischarge period. The safety and efficacy of inferior vena cava filters in bariatric surgical patients is highly heterogeneous. There were no randomised trials that analysed prophylaxis of venous thromboembolism in obese patients undergoing nonbariatric surgery. Higher doses of anticoagulants could be proposed for obese patients with a BMI more than 40 kg m. The lack of good quality randomised trials with a low risk of bias did not allow us to propose strong recommendations.

European guidelines on perioperative venous thromboembolism prophylaxis: Patients with preexisting coagulation disorders and after severe perioperative bleeding.

: In patients with inherited bleeding disorders undergoing surgery, we recommend assessment of individual risk for venous thromboembolism, taking into account the nature of the surgery and anaesthetic, type and severity of bleeding disorder, age, BMI, history of thrombosis, the presence of malignancy and other high-risk comorbidities. Venous thromboembolism risk should be balanced against the increased bleeding risk associated with anticoagulant use in patients with known bleeding disorders (Grade 1C). In these patients undergoing major surgery, we recommend against routine postoperative use of pharmacological thromboprophylaxis, especially for patients with haemophilia A and B (Grade 1B). Glomerular filtration rate should be assessed before initiation of each direct oral anticoagulant, and also at least once a year or more frequently as needed, such as postoperatively before the resumption of therapeutic direct oral anticoagulant administration, when it is suspected that renal function could decline or deteriorate (Grade 1C). Reduced dosages of low molecular weight heparins may be used relatively safely during transient severe (<50 × 10 l) thrombocytopaenia (Grade 2C). Monitoring of anti-Xa levels may be used to adjust the doses of low molecular weight heparin in patients with moderate or severe thrombocytopaenia (Grade 2C). The delay between major gastrointestinal bleeding and resuming warfarin should be at least 7 days (Grade 2C). For patients at a high risk of thromboembolism and with a high bleeding risk after surgery, we consider that administering a reduced dose of direct oral anticoagulant on the evening after surgery and on the following day (first postoperative day) after surgery is a good practice (Grade 2B).

European guidelines on perioperative venous thromboembolism prophylaxis: Mechanical prophylaxis.

: Institutional protocols need to address the indications for pharmacological and mechanical thromboprophylaxis. The use of graduated compression stockings (GCS) and intermittent pneumatic compression (IPC) strongly differs between institutions. As a consequence, no strong recommendations can be made based on the contemporary high-level evidence. Although different clinical practices can be supported, such approaches should be part of an institutional strategy to reduce the burden of venous thromboembolism (VTE). We recommend against the use of GCS alone without pharmacological thromboprophylaxis for prevention of VTE in patients at intermediate and high risk. For patients at high risk of VTE with contraindications for pharmacological thromboprophylaxis, we recommend the use of mechanical prophylaxis and suggest the use of IPC over GCS. However, for those patients receiving pharmacological thromboprophylaxis who are without a very high risk of VTE prophylaxis, we recommend against the routine use of mechanical thromboprophylaxis either with GCS or IPC. We suggest combined mechanical and pharmacological prophylaxis in selected patients at very high risk of VTE prophylaxis and suggest IPC rather than GCS in these selected patients.

European guidelines on perioperative venous thromboembolism prophylaxis: Intensive care.

: Venous thromboembolism is a common and potentially life-threatening complication that occurs in 4 to 15% of patients admitted to ICUs despite the routine use of pharmacological prophylaxis. We therefore recommend an institution-wide protocol for the prevention of venous thromboembolism (Grade 1B). The routine use of ultrasonographic screening for deep vein thrombosis is not recommended when thromboprophylactic measures are in place (Grade 1B), as the detection of asymptomatic deep vein thrombosis may prompt therapeutic anticoagulation that may increase bleeding risk but has no proven reduction of clinically significant thrombotic events. In critically ill patients, we recommend pharmacological prophylaxis with low molecular weight heparin over low-dose heparin (Grade 1B). For critically ill patients with severe renal insufficiency, we suggest the use of low-dose heparin (Grade 2C), dalteparin (Grade 2B) or reduced doses of enoxaparin (Grade 2C). Monitoring of anti-Xa activity may be considered when low molecular weight heparin is used in these patients (Grade 2C). No study has prospectively evaluated the efficacy and safety of deep vein thrombosis prophylaxis in critically ill patients with severe liver dysfunction. Thus, the use of pharmacological prophylaxis in these patients should be carefully balanced against the risk of bleeding. For critically ill patients, we recommend against the routine use of inferior vena cava filters for the primary prevention of venous thromboembolism (Grade 1C). When the diagnosis of heparin-induced thrombocytopaenia is suspected or confirmed, all forms of heparin must be discontinued (Grade 1B). In these patients, immediate anticoagulation with a nonheparin anticoagulant rather than discontinuation of heparin alone is recommended (Grade 1C).

European guidelines on perioperative venous thromboembolism prophylaxis: Chronic treatments with antiplatelet agents.

: Antiplatelet agents (APA) are considered first-line therapy in preventing cardiovascular thrombotic events, but they are of limited value in the prophylaxis of venous thromboembolism (VTE) during the perioperative period. Consequently, many patients should receive both an APA and an anticoagulant. This combination can increase the bleeding risk and it is necessary to make some recommendations to minimise that risk. In patients receiving APA chronically, if the risk of VTE outweighs the risk of bleeding, we suggest pharmacological prophylaxis (grade 2C). In patients treated with dual antiplatelet therapy undergoing a procedure associated with a high risk of VTE, resuming both APA shortly after the procedure must be prioritised over pharmacological VTE prevention (grade 2C). If the risk of bleeding from a combination of an APA and an anticoagulant outweighs the risk of VTE, we suggest mechanical thromboprophylaxis over anticoagulant prophylaxis, without discontinuing the APA (grade 2C). Patients in whom neuraxial anaesthesia is planned, a higher rate of complications could occur if pharmacological thromboprophylaxis is administered concurrently and postoperative thromboprophylaxis initiation should be suggested (grade 2C). After surgery, the first dose of aspirin should be given once haemostasis is guaranteed (grade 2B). In the case of clopidogrel, give the drug without a loading dose between 24 and 48 h after surgery (grade 2C).