Hemorrhagic Complications of Anticoagulant Treatment

Life expectancy in cancer patients with pulmonary thromboembolism: From clinical prognostic biomarkers and paraclinical investigations to therapeutic approaches (Review)

Pulmonary embolisms (PEs) are obstructions of the pulmonary arteries by thrombi, which are emboli and they most frequently originate from the deep venous system of the inferior limbs. Emboli can also come from the inferior vena cava, abdominal and pelvic veins, or the upper body venous system from the right atrium or ventricle of the heart. Thrombi can form in situ inside pulmonary arteries as well. A cancer patient is at a higher risk for thromboembolic phenomena given both the oncological pathological context and also due to the associated medical or surgical treatment they receive. PE is a high-risk medical emergency that is associated with an increased risk of early mortality, with sudden death occurring in 25% of patients. The long-term presence of this condition can result in thromboembolic pulmonary hypertension. The risk of mortality, both in the acute and long-term, is dependent on the severity of the acute form, the recurrence of the embolism and the associated conditions. The majority of deaths associated with PE can be prevented by early diagnosis. The aim of the present review was to describe the various biological and cellular parameters, together with known paraclinical investigations, to assist in the rapid diagnosis of PE. Mortality in patients with PE and neoplastic conditions may be reduced by initiating anticoagulant treatment as soon as possible. PE may be the first manifestation of an underlying silent malignancy or may represent a complication of an already diagnosed malignancy. Exclusion or confirmation of the diagnosis is of utmost importance to avoid unnecessary anticoagulant treatment associated with a high risk of bleeding or to start immediate anticoagulant treatment if required.

Small bowel intramural hematoma caused by warfarin: case report and literature review

BACKGROUND

Intramural hematoma of the small bowel is a rare yet acute gastrointestinal condition typically linked with impaired coagulation function, often posing diagnostic challenges. It is principally encountered in patients undergoing prolonged anticoagulant therapy, specifically warfarin.

CASE PRESENTATION

We reported a case of intramural hematoma associated with warfarin use. The patient was admitted to hospital with abdominal pain and had received anticoagulant therapy with warfarin 2.5 mg/day for 4 years. Laboratory examination showed decreased coagulation function, abdominal CT showed obvious thickening and swelling of part of the jejunal wall, and abdominal puncture found no gastroenteric fluid or purulent fluid. We treated the patient with vitamin K and fresh frozen plasma. The patient was discharged after the recovery of coagulation function. Then we undertaook a comprehensive review of relevant case reports to extract shared clinical features and effective therapeutic strategies.

CONCLUSION

Our analysis highlights that hematoma in the small intestinal wall caused by warfarin overdose often presents as sudden and intense abdominal pain, laboratory tests suggest reduced coagulation capacity, and imaging often shows thickening of the intestinal wall. Intravenous vitamin K and plasma supplementation are effective non-surgical strategies. Nevertheless, in instances of severe obstruction and unresponsive hemostasis, surgical resection of necrotic intestinal segments may be necessary. In the cases we reported, we avoided surgery by closely monitoring the coagulation function. Therefore, we suggest that identifying and correcting the impaired coagulation status of patient is essential for timely and appropriate treatment.

Early Time Courses of Recurrent Venous Thromboembolism and Bleeding during Apixaban or Dalteparin Therapy for Patients with Cancer

BACKGROUND

 In patients with acute venous thromboembolism (VTE), the rates of recurrence and major bleeding are highest during the first weeks of anticoagulation. The CARAVAGGIO trial demonstrated noninferiority of apixaban to dalteparin for treatment of cancer-associated VTE without an increased risk of major bleeding. We compared the early time course of VTE recurrence and major bleeding events of apixaban compared with dalteparin at 7, 30, and 90 days of treatment in patients with cancer-associated VTE.

METHODS

 The study design of the CARAVAGGIO trial has been described. Eligible patients were randomly assigned to receive monotherapy with either apixaban or dalteparin for 6 months. The primary efficacy outcome was the incidence of objectively confirmed recurrent VTE. The primary safety outcome was major bleeding.

RESULTS

 In 1,155 patients, recurrent VTE after 7, 30, and 90 days occurred in 6 (1%), 15 (2.6%), and 27 (4.7%) patients in the apixaban arm versus 5 (0.9%), 20 (3.5%), and 36 (6.2%) patients respectively in the dalteparin arm. By day 7, 30, and 90, major bleeding events had occurred in 3 (0.5%), 9 (1.6%), and 16 (2.8%) patients in the apixaban group versus 5 (0.9%), 11 (1.9%), and 17 (2.9%) patients in the dalteparin group.

CONCLUSION

 The frequencies of recurrent VTE and major bleeding events at 7, 30, and 90 days of apixaban compared with dalteparin were similar in patients with cancer-associated VTE. This supports the use of apixaban for the initiation and early phase of anticoagulant therapy in cancer-associated VTE.

A Randomized Trial Comparing Standard of Care to Bayesian Warfarin Dose Individualization

The quality of warfarin treatment may be improved if management is guided by the use of models based upon pharmacokinetic-pharmacodynamic theory. A prospective, two-armed, single-blind, randomized controlled trial compared management aided by a web-based dose calculator (NextDose) with standard clinical care. Participants were 240 adults receiving warfarin therapy following cardiac surgery, followed up until the first outpatient appointment at least 3 months after warfarin initiation. We compared the percentage of time spent in the international normalized ratio acceptable range (%TIR) during the first 28 days following warfarin initiation, and %TIR and count of bleeding events over the entire follow-up period. Two hundred thirty-four participants were followed up to day 28 (NextDose: 116 and standard of care: 118), and 228 participants (114 per arm) were followed up to the final study visit. Median %TIR tended to be higher for participants receiving NextDose guided warfarin management during the first 28 days (63 vs. 56%, P = 0.13) and over the entire follow-up period (74 vs. 71%, P = 0.04). The hazard of clinically relevant minor bleeding events was lower for participants in the NextDose arm (hazard ratio: 0.21, P = 0.041). In NextDose, there were 89.3% of proposed doses accepted by prescribers. NextDose guided dose management in cardiac surgery patients requiring warfarin was associated with an increase in %TIR across the full follow-up period and fewer hemorrhagic events. A theory-based, pharmacologically guided approach facilitates higher quality warfarin anticoagulation. An important practical benefit is a reduced requirement for clinical experience of warfarin management.

Abdominoplasty after massive weight loss. Safety preservation fascia technique and clinical outcomes in a large single series-comparative study

Introduction

Weight loss after bariatric surgery causes very important modifications to the patient's silhouette. Abdominal fat and skin excess reduction are associated with several complications. The most frequent are seroma and hematoma whereas major complications, such as pulmonary embolism, are less frequent. This study aimed to describe our technical procedure for abdominoplasty in patients with massive weight loss after bariatric surgery.

Methods

In total, 196 patients were included. All patients who underwent abdominoplasty classic (group A) and abdominoplasty with the preservation and lift of Scarpa fascia (group B) and with umbilical transposition between May 2018 and May 2021 were included. Patients with concomitant correction of ventral hernia were excluded. Demographic and operative data were analyzed according to comorbidities and postoperative complications.

Results

There were 160 (81.6%) women. The mean age was 43.6 years; the mean weight was 86.7 kg; and the mean BMI was 28.6 kg/m2. Five patients (2.5%) presented postoperative seroma. Four patients (2%) presented partial dehiscence/skin necrosis one of them requiring a revision. Finally, 26 patients presented a postoperative complication, with an overall incidence of 12.6%. The average postoperative hospital stay was 3.6. The rates of seroma were significantly higher in men, patients with a BMI > 30 kg/m2, and aged >50 years.

Conclusion

Preserving Scarpa Fascia during surgical post-bariatric patient procedures reduces the seroma formation and the scar complication and reduces the tension of the inguinal-pubic region with correction of our deformation after weight loss. Improves reducing the drain and reducing seroma incidence suction and hospital stay.

Optimisation of warfarin-dosing algorithms for Han Chinese patients with CYP2C9*13 variants

BACKGROUND

Existing pharmacogenetic algorithms cannot fully explain warfarin dose variability in all patients. CYP2C9*13 is an important allelic variant in the Han Chinese population. However, adjustment of warfarin dosing in CYP2C9*13 variant carriers remains unclear. To the best of our knowledge, this study is the first to assess the effects of adjusting warfarin dosages in Han Chinese patients harbouring CYP2C9*13 variants.

METHODS

In total, 971 warfarin-treated Han Chinese patients with atrial fibrillation were enrolled in this study. Clinical data were collected, and CYP2C9*2, *3, *13 and VKORC1-1639 G > A variants were genotyped. We quantitatively analysed the effect of CYP2C9*13 on warfarin maintenance dose and provided multiplicative adjustments for CYP2C9*13 using validated pharmacogenetic algorithms.

RESULTS

Approximately 0.6% of the Han Chinese population carried CYP2C9*13 variant, and the genotype frequency was between those of CYP2C9*2 and CYP2C9*3. The warfarin maintenance doses were significantly reduced in CYP2C9*13 carriers. When CYP2C9*13 variants were not considered, the pharmacogenetic algorithms overestimated warfarin maintenance doses by 1.03-1.16 mg/d on average. The actual warfarin dose in CYP2C9*13 variant carriers was approximately 40% lower than the algorithm-predicted dose. Adjusting the warfarin-dosing algorithm according to the CYP2C9*13 allele could reduce the dose prediction error.

CONCLUSION

Our study showed that the algorithm-predicted doses should be lowered for CYP2C9*13 carriers. Inclusion of the CYP2C9*13 variant in the warfarin-dosing algorithm tends to predict the warfarin maintenance dose more accurately and improves the efficacy and safety of warfarin administration in Han Chinese patients.

The methods for removal of direct oral anticoagulants and heparins to improve the monitoring of hemostasis: a narrative literature review

The assessment of hemostasis is necessary to make suitable decisions on the management of patients with thrombotic disorders. In some clinical situations, for example, during thrombophilia screening, the presence of anticoagulants in sample makes diagnosis impossible. Various elimination methods may overcome anticoagulant interference. DOAC-Stop, DOAC-Remove and DOAC Filter are available methods to remove direct oral anticoagulants in diagnostic tests, although there are still reports on their incomplete efficacy in several assays. The new antidotes for direct oral anticoagulants - idarucizumab and andexanet alfa - could be potentially useful, but have their drawbacks. The necessity to remove heparins is also arising as heparin contamination from central venous catheter or therapy with heparin disturbs the appropriate hemostasis assessment. Heparinase and polybrene are already present in commercial reagents but a fully-effective neutralizer is still a challenge for researchers, thus promising candidates remain in the research phase.

Advances in symptomatic therapy for left ventricular non-compaction in children

Left ventricular non-compaction is a complex cardiomyopathy and the third largest childhood cardiomyopathy, for which limited knowledge is available. Both pathogenesis and prognosis are still under investigation. Currently, no effective treatment strategy exists to reduce its incidence or severity, and symptomatic treatment is the only clinical treatment strategy. Treatment strategies are constantly explored in clinical practice, and some progress has been made in coping with the corresponding symptoms because the prognosis of children with left ventricular non-compaction is usually poor if there are complications. In this review, we summarized and discussed the coping methods for different left ventricular non-compaction symptoms.

Antithrombotics and Gastrointestinal Prophylaxis: A Systematic Review

Antithrombotic medications include both antiplatelet and anticoagulants and are used for a wide variety of cardiovascular conditions. A common complication of antithrombotic use is gastrointestinal bleeding. As a result, gastrointestinal prophylaxis is a common consideration for patients on a single or combination antithrombotic regimen. Prophylaxis is typically achieved through use of either proton pump inhibitors or histamine 2 receptor antagonists. Current recommendations for use of gastrointestinal prophylaxis with concomitant use of antithrombotic medications are scarce. In this systematic review, we explore the current evidence and recommendations regarding gastrointestinal prophylaxis for patients on antiplatelet or anticoagulant therapy as well as combination regimens.

The association between hemoglobin A1c and all-cause mortality in the ICU: A cross-section study based on MIMIC-IV 2.0

BACKGROUND

Hyperglycemia has been reported to be associated with the outcomes of patients in the intensive care unit (ICU). However, the relationship between hemoglobin A1c (HbA1c) and long-term or short-term mortality in the ICU is still unknown. This study used the Medical Information Mart for Intensive Care (MIMIC)-IV database to investigate the relationship between HbA1c and long-term or short-term mortality among ICU patients without a diabetes diagnosis.

METHODS

A total of 3,154 critically ill patients without a diabetes diagnosis who had HbA1c measurements were extracted and analyzed from the MIMIC-IV. The primary outcome was 1-year mortality, while the secondary outcomes were 30-day mortality and 90-day mortality after ICU discharge. HbA1c levels were classified into four levels according to three HbA1c values (5.0%, 5.7%, and 6.5%). The Cox regression model was used to investigate the relationship between the highest HbA1c measurement and mortality. Finally, this correlation was validated using the XGBoost machine learning model and Cox regression after propensity score matching (PSM).

RESULTS

The study eventually included 3,154 critically ill patients without diabetes who had HbA1c measurements in the database. HbA1c levels of below 5.0% or above 6.5% were significantly associated with 1-year mortality after adjusting for covariates in Cox regression (HR: 1.37; 95% CI: 1.02-1.84 or HR: 1.62; 95% CI: 1.20-2.18). In addition, HbA1c 6.5% was linked to 30-day mortality (HR: 1.81; 95% CI: 1.21-2.71) and 90-day mortality (HR: 1.62; 95% CI: 1.14-2.29). The restricted cubic spline demonstrated a U-shaped relationship between HbA1c levels and 1-year mortality. The AUCs of the training and testing datasets in the XGBoost model were 0.928 and 0.826, respectively, while the SHAP plot revealed that HbA1c was somewhat important for the 1-year mortality. Higher HbA1c levels in Cox regression were still significantly associated with 1-year mortality after PSM for other factors.

CONCLUSIONS

The 1-year mortality, 30-day mortality, and 90-day mortality rates for critically ill patients after discharge from ICU are significantly associated with HbA1c. HbA1c < 5.0% and ≥6.5% would increase 30-day, 90-day, and 1-year mortality, while levels between 5.0% and 6.5% of HbA1c did not significantly affect these outcomes.

Use of tramadol and the risk of bleeding complications in patients on oral anticoagulants: a systematic review and meta-analysis

PURPOSE

This systematic review and meta-analysis aimed to determine whether tramadol intake increases the risk of bleeding in patients receiving oral anticoagulants.

METHODS

This systematic review was registered on PROSPERO, CRD42022327230. We searched PubMed and Embase up to 14 April 2022, and references and citations of included studies were screened. Comparative and non-comparative studies exploring bleeding complications among adult patients on oral anticoagulants and tramadol were included. Risk of bias was assessed using an adaptation of the Drug Interaction Probability Scale for case reports and case series and the Newcastle-Ottawa Scale for comparative studies. A meta-analysis was performed for the risk of serious bleeding (leading to hospitalisation or death) associated with tramadol in patients on vitamin K antagonists.

RESULTS

A total of 17 studies were included: 1 case series, 12 case reports, 2 case-control studies and 2 cohort studies. Most of the studies described tramadol-vitamin K antagonists' concomitant use; one case-control study also assessed dabigatran and rivaroxaban; one case report involved dabigatran. Among case reports/series, a total of 33 patients had a bleeding complication while using tramadol and an oral anticoagulant. The 4 comparative studies reported an increased bleeding risk during tramadol and vitamin K antagonist intake which was statistically significant in one study; the pooled risk ratio of serious bleeding was 2.68 [95% CI: 1.45 to 4.96; p < 0.001].

CONCLUSION

This systematic review confirms an association between tramadol use and risk of bleeding in patients on vitamin K antagonists. Evidence is too limited to assess whether this risk extends to patients on direct oral anticoagulants, and further studies are needed.

Intravenous cannula induced phlebitis in a tertiary care referral hospital: A prospective observational study with implication from patient's feedback system

BACKGROUND

Medicines delivered directly to systemic circulation have saved many lives from life-threatening conditions, but also can impart undesirable effects.

MATERIALS AND METHODS

A prospective observational study was performed for 10 months in the tertiary care hospital to identify and evaluate cannula induced phlebitis in our study population. The data collection form retrieved demographic details, diseases and cannulation particulars of each patient. Moreover, a patient feedback questionnaire (Cronbach's alpha=0.70) retrieved their concerns toward cannulation.

RESULTS

Phlebitis was identified in 96 patients out of 146 subjects enrolled in the study; 52% had the first sign of phlebitis. Female patients were more prone, and the complication occurred irrespective of age (p>0.05). On the other hand, those on IV cefoperazone-sulbactam (n=13, 13.5%) followed by amoxicillin clavulanic acid (n=6, 6%) had significant cannulation complication (p<0.01). The cannula indwells time (p=0.001) and vein assessment (p=0.001) were statistically associated with incidence of phlebitis. Half of our samples had pain lasting about five minutes (χ²=9.2, p<0.05). Nevertheless, limited patients (n = 35, 36.5%) were prescribed topical Heparin Benzyl Nitrate, and none preferred to self-medicate nor opted for other home remedies.

CONCLUSIONS

The study depicted high prevalence of phlebitis factored in by poor vein assessment and increase in indwelling time. We recommend proper awareness with on-site skill improvement program for health professionals on administration techniques and monitoring principles in order to lower cannulation related complications.

Warfarin-induced spontaneous intramural small bowel hematoma presenting as an acute abdomen: A case report

RATIONALE

Spontaneous intramural small-bowel hematoma (SISBH) is a rare complication of anticoagulation therapy. Presentation of SISBH can vary from mild abdominal pain to an acute abdomen.

PATIENT CONCERNS

A 70-year-old woman was brought to the emergency department because of severe abdominal pain for 1 day. She had a medical history of coronary artery disease and paroxysmal atrial fibrillation and was receiving anticoagulation therapy with warfarin for 3 years.

DIAGNOSIS

Computed tomography disclosed disproportional dilatation of the segmental small bowel and near-total obstruction of the intestinal lumen at the level of the jejunum, indicating an acute abdomen.

INTERVENTIONS

We performed laparoscopic exploration and found a segmental distal jejunum was tense, heavy, firm, and discolored with a blue hue. Histopathological examination of the resected jejunum revealed diffuse hemorrhage and necrosis at the mucosa and submucosal layers, indicating SISBH.

OUTCOMES

The patient had an uneventful recovery and was discharged in a relatively stable condition.

LESSONS

Warfarin-induced SISBH presenting as an acute abdomen is an emergency condition that needs early diagnosis and timely management. Surgical intervention may be indicated for intestinal obstruction, ischemia, perforation, peritonitis, and intra-abdominal hemorrhage.

Critical Appraisal of a Systematic Review: A Concise Review

OBJECTIVES

Concise definitive review of how to read and critically appraise a systematic review.

DATA SOURCES

None.

STUDY SELECTION

Current literature describing the conduct, reporting, and appraisal of systematic reviews and meta-analyses.

DATA EXTRACTION

Best practices for conducting, reporting, and appraising systematic review were summarized.

DATA SYNTHESIS

A systematic review is a review of a clearly formulated question that uses systematic and explicit methods to identify, select, and critically appraise relevant original research, and to collect and analyze data from the studies that are included in the review. Critical appraisal methods address both the credibility (quality of conduct) and rate the confidence in the quality of summarized evidence from a systematic review. The A Measurement Tool to Assess Systematic Reviews-2 tool is a widely used practical tool to appraise the conduct of a systematic review. Confidence in estimates of effect is determined by assessing for risk of bias, inconsistency of results, imprecision, indirectness of evidence, and publication bias.

CONCLUSIONS

Systematic reviews are transparent and reproducible summaries of research and conclusions drawn from them are only as credible and reliable as their development process and the studies which form the systematic review. Applying evidence from a systematic review to patient care considers whether the results can be directly applied, whether all important outcomes have been considered, and if the benefits are worth potential harms and costs.

Neurological Complications of Pulmonary Embolism: a Literature Review

PURPOSE OF REVIEW

The present review discusses in-depth about neurological complications following acute venous thromboembolism (VTE).

RECENT FINDINGS

Intracranial hemorrhage, acute ischemic cerebrovascular events, and VTE in brain tumors are described as central nervous system (CNS) complications of PE, while peripheral neuropathy and neuropathic pain are reported as peripheral nervous system (PNS) sequelae of PE. Syncope and seizure are illustrated as atypical neurological presentations of PE. Mounting evidence suggests higher risk of venous thromboembolism (VTE) in patients with neurological diseases, but data on reverse, i.e., neurological sequelae following VTE, is underexplored. The present review is an attempt to explore some of the latter issues categorized into CNS, PNS, and atypical complications following VTE.

Coagulation Status and Surgical Approach as Predictors of Postoperative Anemia in Patients Undergoing Thoracic Surgery: A Retrospective Study

Objective: Postoperative anemia is a common complication after a major surgery. Our study aims to identify factors that are associated with higher risk of developing postoperative anemia after thoracic surgery.

Methods: We conducted a retrospective study of 465 patients who underwent pulmonary surgery in 2017 in Shanghai Pulmonary Hospital, China. Of them, 191 patients underwent standard open thoracotomy (OT), and 274 patients underwent video-assisted thoracic surgery (VATS). A total of 350 patients were diagnosed with postoperative anemia, and 115 patients did not have anemia. Multiple logistic regression was used to compute odds ratios for predicting preoperative anemia.

Results: Postoperative anemia was associated with significantly lower weight (p < 0.001) and height (p = 0.022) of the patients, as well as higher prothrombin time (PT), and international normalized ratio (INR) (p = 0.012). Open thoracotomy resulted in a 1.2-fold increase in the incidence of postoperative anemia compared to VATS (p = 0.002). Multiple logistic regression analysis identified INR [OR (95% CI) 24.46 (2.05–292.27; p = 0.012] and surgical approach [OR (95% CI) 0.48 (0.31–0.74); p < 0.001] as predictors of postoperative anemia and postoperative drop in hemoglobin (Hb).

Conclusion: Postoperative coagulation status and surgical approach are statistically significant predictors of postoperative anemia in patients undergoing thoracic surgery. International normalized ratio and surgical approach are specifically associated with Hb drop immediately after the surgery.

Evaluation of a pharmacist vs. Haematologist-managed anticoagulation clinic: A retrospective cohort study

INTRODUCTION

Warfarin is the core component in the management of various thromboembolic disorders, which requires specialized expertise to optimize outcomes. There is limited data comparing a pharmacist vs. a haematologist-managed anticoagulation clinic in our setting, and in the Middle East. We aimed to evaluate the effectiveness and safety of a pharmacist vs. a haematologist-managed anticoagulation clinic in the Ambulatory Care Center at King Abdulaziz Medical City, Jeddah, Saudi Arabia.

METHODS

A retrospective cohort study was conducted from 2016 to 2018, which included adult patients who have been followed-up for at least six months and who received warfarin for an extended period. The primary outcome was the proportion of time the patients in the two arms were in the therapeutic range. The secondary outcomes were the differences in expanded time in the therapeutic range, as well as the frequency of bleeding and thromboembolic events between the two arms.

RESULTS

We enrolled 104 and 124 patients in the pharmacist and haematologist arms respectively. The median time in the therapeutic range for the pharmacist arm was 71.4%, IQR (60.8-83.8) vs. 65%, IQR (43.5-79.1), in the haematologist arm (p = 0.0049). The median expanded time in the therapeutic range was 86.4%, IQR (77.5-95.3) vs. 81.21%, IQR (67.1-93.3) in the pharmacist vs. haematologist arm (p = 0.015) respectively. Major bleeding events occurred in 5.7 % vs. 3.2 %, and thromboembolic events in 5.7% vs. 4%, in the pharmacist vs. haematologist arm respectively.

CONCLUSIONS

Our results demonstrated that the time in the therapeutic range was significantly higher in the pharmacist arm, with no significant difference in bleeding and thromboembolic events compared to the haematologist arm.

2021 John N. Insall Award: Aspirin is effective in preventing propagation of infrapopliteal deep venous thrombosis following total knee arthroplasty

AIMS

The optimal management of an infrapopliteal deep venous thrombosis (IDVT) following total knee arthroplasty (TKA) remains unknown. The risk of DVT propagation and symptom progression must be balanced against potential haemorrhagic complications associated with administration of anticoagulation therapy. The current study reports on a cohort of patients diagnosed with IDVT following TKA who were treated with aspirin, followed closely for development of symptoms, and scanned with ultrasound to determine resolution of IDVT.

METHODS

Among a cohort of 5,078 patients undergoing TKA, 532 patients (695 TKAs, 12.6%) developed an IDVT between 1 January 2014 to 31 December 2019 at a single institution, as diagnosed using Doppler ultrasound at the first postoperative visit. Of the entire cohort of 532 patients with IDVT, 91.4% (486/532) were treated with aspirin (325 mg twice daily) and followed closely. Repeat lower limb ultrasound was performed four weeks later to evaluate the status of IDVT.

RESULTS

Follow-up Doppler ultrasound was performed on 459/486 (94.4%) patients and demonstrated resolution of IDVT in 445/459 cases (96.9%). Doppler diagnosed propagation of IDVT to the popliteal vein had occurred in 10/459 (2.2%) cases. One patient with an IDVT developed a pulmonary embolus six weeks postoperatively.

CONCLUSION

The results of this study demonstrate a low rate of IDVT propagation in patients managed with aspirin. Additionally, no significant bleeding episodes, wound-related complications, or other adverse events were noted from aspirin therapy. Cite this article: Bone Joint J 2021;103-B(6 Supple A):18-22.

Case Report: Spontaneous Intramural Hematoma of the Colon Secondary to Low Molecular Weight Heparin Therapy

Background: Hematoma of the colon is a rare hemorrhagic complication that affects patients accepting low molecular weight heparin (LMWH) therapy. Only scarce cases of colon hematoma have been reported, usually in children or patients accepting warfarin therapy. Case summary: A 76-year-old Chinese man was diagnosed with atrial fibrillation and heart failure, with cardiac function NYHA grade III on March 21, 2018. This patient was given LMWH for anticoagulation therapy and developed a colon hematoma on the third day of hospitalization. Abdominal computed tomography (CT) showed the thickening of areas of the colon up to 110 mm × 78 mm in thickness, which was a symptom of colon hematoma. The patient underwent conservative treatment successfully. On March 27, the patient's abdominal pain was alleviated, and a CT scan showed that the intestinal hematoma was absorbed. Conclusions: The most frequent minor bleeding events of LMWH anticoagulation are hemorrhage and subcutaneous hematoma. This case demonstrated that bowel hematoma despite its low incidence should be considered as an ADR of LMWH therapy, especially among patients who present with gastrointestinal symptoms.

Effects of rare CYP2C9 alleles on stable warfarin doses in Chinese Han patients with atrial fibrillation

Aim: Gene polymorphisms are critical in warfarin dosing variation. Here, the role of rare CYP2C9 alleles on warfarin doses in Chinese Han patients was investigated. Methods: A retrospective study recruited 681 warfarin treated atrial fibrillation patients. The genetic and clinical data were collected. Dose-related variables were selected by univariate analyses and the warfarin-dosing algorithm was derived by multivariate regression analysis. Results: Three rare CYP2C9 alleles (CYP2C9*13, *16 and *60) were associated with lower stable doses. Inclusion of the rare CYP2C9 alleles in the prediction model added an extra 3.7% warfarin dose predictive power. Conclusion: CYP2C9*13, *16 and *60 was associated with lower stable warfarin doses in Chinese patients. The algorithm including rare CYP2C9 alleles tends to more accurately predict stable warfarin doses.

Delayed Intracranial Hemorrhage After Blunt Head Injury With Direct Oral Anticoagulants

INTRODUCTION

Patients presenting to the Emergency Department (ED) following head injury are frequently evaluated with an initial computed tomography scan (CT) of the brain. Imaging is particularly important in patients who are receiving medications that alter normal blood hemostasis. As an imaging modality, CT has a high negative predictive value when used to rule out clinically significant acute intracranial hemorrhage. Patients receiving anticoagulant or antiplatelet therapy have both an increased risk of initial hemorrhage, as well as an increased risk of mortality above nonanticoagulated patients, should they suffer hemorrhage. Multiple studies of delayed intracranial hemorrhage have placed the risk among the patients taking warfarin at the time of head injury in the range of 0.6-6.0%. However, data regarding the risk of delayed intracranial hemorrhage in patients taking the class of agents referred to as Direct-Acting Oral Anticoagulants (DOACs) remains limited. This study aims to estimate this risk.

METHODS

A retrospective chart review was performed to identify patients on DOACs who presented to our Level I trauma center following blunt head injury between January 2017 and August 2018. Patients with a negative initial head CT were selected. From this subset, data regarding demographics, injury characteristics, anticoagulant use, and antiplatelet use were collected.

RESULTS

Overall, 314 patients were included; 129 patients taking rivaroxaban, 182 patients taking apixaban, and four patients taking dabigatran. In approximately 29% of the patients, the sole indication for admission was close monitoring following head injury while taking an anticoagulant agent. The mechanism of injury for the majority of the patients was fall. Of the 314 patients, three were found to have delayed intracranial hemorrhage on the repeated head CT (0.95%). Two of these three patients were on concomitant antiplatelet medication. None of the three individuals required neurosurgical intervention.

CONCLUSIONS

at the time of submission, this is the largest study estimating the risk of delayed intracranial hemorrhage among patients on DOACs. Based on the results of this study, patients who sustain a blunt head injury while taking only DOACs; that is, without concurrent antiplatelet medication, admission, and repeat head CT may not be necessary after confirming a negative initial CT scan.

Elevated HbA1c is not associated with recurrent venous thromboembolism in the elderly, but with all-cause mortality- the SWEETCO 65+ study

The association of glycated hemoglobin (HbA1c) with venous thromboembolism (VTE) and death in the elderly is unknown. In the SWEETCO 65+ study we analyzed prospectively a Swiss Cohort of Elderly Patients with Venous Thromboembolism (SWITCO 65+). 888 patients were enrolled for the SWEETCO 65+ analysis. HbA1c was determined at baseline and divided into three categories (HbA1c < 5.7%, normal range; 5.7–6.49%, pre-diabetic range; and >6.5%, diabetic range). Median follow-up was 2.5 years. The primary endpoint was recurrent VTE. Secondary endpoints included all-cause mortality and major bleeds. The total prevalence of diabetes was 22.1%. The risk of recurrent VTE was similar in patients with HbA1c with pre-diabetes (adjusted subhazard ratio (aSHR) 1.07 [0.70 to 1.63]) and diabetes (aSHR 0.73 [0.39 to 1.37]) as compared to those with a HbA1c in the normal range. However, a HbA1c ≥ 6.5% (median IQ range 7.0 [6.70;7.60]) was significantly associated with a higher risk of all-cause mortality (adjusted hazard ratio [aHR] 1.83 [1.21 to 2.75]). In summary we found no association between HbA1c and major bleeding. Elevated HbA1c levels are not associated with recurrent VTE but with increased all-cause mortality in an elderly population with acute VTE.

Venous thromboembolism rates after hip and knee arthroplasty and hip fractures

BACKGROUND

The ideal thromboprophylaxis regime following lower limb arthroplasty and proximal femur fractures remains controversial. Guidelines disagree on the type of chemical prophylaxis, its dose or duration. This article describes a method of monitoring venous thromboembolism (VTE) rates following Total Hip (THA), Total Knee Arthroplasty (TKA) and surgery for hip fractures (NOF#).

METHODS

Over 3 years, all patients investigated for VTE were analysed using Picture Archiving Communications System (PACS). All positive scans were then cross-referenced using PACS and local registry data to see if they had undergone THA, TKA or NOF# in the preceding 90 days. Mortality data were obtained from the national administrative database, Hospital Episode Statistics.

RESULTS

Five thousand seven hundred eighty-eight patients underwent investigation for VTE and there were 29 diagnoses of PE and 24 of DVT. There was a 0.77% rate of symptomatic DVT after THA, 0.05% after TKA and 0.55% after NOF #. The rate of confirmed symptomatic PE for THA was 0.46, 0.27% for TKA and 0.96% for NOF #. Mortality at one-year post-THA was 0.6, 0.6% for TKA and 25.9% after NOF#. All patients contacted either remained within the catchment area for the minimum 90 postoperative days or died within the catchment area.

CONCLUSIONS

The 90 day post-operative prevalence of symptomatic VTE of 1.2, 0.3 and 1.5% in THA, TKA and NOF # respectively are similar to other studies using symptomatic and imaging positive VTE as their endpoint. The study uses a method of collecting data which can be utilised in centres where PACS is available.

Programmed Release of Multimodal, Cross-Linked Vascular Endothelial Growth Factor and Heparin Layers on Electrospun Polycaprolactone Vascular Grafts

Viable tissue-engineering small-diameter vascular grafts should support rapid growth of an endothelial cell layer and exhibit long-term antithrombogenic property. In this study, multiple layers of various bioactive molecules, such as vascular endothelial growth factor (VEGF) and heparin, on an electrospun polycaprolactone scaffold have been developed through repeated electrostatic adsorption self-assembly (up to 20 layers), followed by genipin cross-linking. Programmed and sustained release of biomolecules embedded within the multilayered structure can be triggered by matrix metallopeptidase 2 enzyme in vitro. The result is an early and full release of VEGF to promote rapid endothelialization on the intended vascular grafts, followed by a gradual but sustained release of heparin for long-term anticoagulation and antithrombogenicity. This method of forming a biologically responsive, multimodal delivery of VEGF and heparin is highly suitable for all hydrophobic surfaces and provides a promising way to meet the critical requirements of engineered small-diameter vascular grafts.

The effect of hospital-based antithrombotic stewardship on adherence to anticoagulant guidelines

Background Anticoagulant therapy is associated with a high risk of complications. Adherence to anticoagulant therapy protocols may lower this risk but adherence is often suboptimal. The introduction of a multidisciplinary antithrombotic team may improve adherence to anticoagulant guidelines among physicians. Objective To determine the effect of hospital-based multidisciplinary antithrombotic stewardship on adherence to anticoagulant guidelines among prescribing physicians. Setting This prospective non-randomised before-and-after study was conducted in patients hospitalized between October 2015 and December 2017 and treated with anticoagulant therapy. Method A multidisciplinary antithrombotic team focusing on education, medication reviews, drafting of local anticoagulant therapy protocols, patient counseling and medication reconciliation at admission and discharge was implemented in two Dutch hospitals. Main outcome measure Primary outcome was the proportion of the admitted patients in which the prescribing physician did adhere to the anticoagulant guidelines. Results The study comprised 1886 patients, of which 941 patients were included in the usual care period and 945 patients in the intervention period. Multivariable logistic regression analysis indicated that adherence was observed significantly more often during the intervention period (adjusted odds ratio [ORadj] 1.58, 95% confidence interval [95% CI] 1.21-2.05). Detailed analysis identified that the significantly higher overall adherence in the intervention period was attributed to dosing of LMWHs (odds ratio [OR] 1.58, 95% CI 1.16-2.14). Conclusion This study shows that introduction of a multidisciplinary antithrombotic stewardship leads to a significantly higher overall adherence to anticoagulant guidelines among prescribing physicians, mainly based on the improvement of dosing of low-molecular-weight-heparins.

Does the use of postoperative low-molecular-weight heparin in patients with lung cancer increase tube drainage?

BACKGROUND

The objectives of this study are to assess the chest drainage volumes of patients undergoing anatomic resection of non-small cell lung carcinoma and to determine the safety and effectiveness of administering enoxaparin for thromboprophylaxis.

METHODS

A total of 77 patients were included in the study. A study was conducted on the first group of 42 patients in which enoxaparin prophylaxis (enoxaparin, 40 mg) was subcutaneously injected once a day for a period of three days after the patients underwent anatomic pulmonary resection between March 2016 and March 2018. An enoxaparin-free group was identified and included 35 patients who received no enoxaparin prophylaxis after undergoing anatomic pulmonary resection between February 2013 and February 2016. We compared the changes in hemoglobin (Hb) levels, postoperative 3-day drainage volume, transfusion volume, pulmonary complications and length of stay between the two groups.

RESULTS

No differences in postoperative Hb levels, chest drainage volume, transfusion volume, postoperative complications, and length of stay were observed between the two groups. Deep-vein thrombosis was noted in a patient in the enoxaparin-free group. No major bleeding was noted in either group.

CONCLUSION

We found that for patients undergoing anatomic resection of primary lung cancer, the blood transfusion and chest drainage volumes did not differ, regardless of whether the patients were given enoxaparin. To the best of our knowledge, the impact of low-molecular-weight heparin on chest tube drainage volume for patients undergoing anatomic resection of non-small cell lung carcinoma has not been investigated before.

Risk of bleeding in hospitalized patients on anticoagulant therapy: Prevalence and potential risk factors

INTRODUCTION

Bleeding is the most important complication of treatment with anticoagulant therapy. Although several studies have identified risk factors of bleeding in outpatients, no studies have been performed that evaluated prevalence and potential risk factors of bleeding in hospitalized patients treated with anticoagulant therapy.

METHODS

The primary objective of this study was to determine the prevalence of bleeding in anticoagulant users during hospitalization. The secondary objective was to identify potential risk factors of bleeding in hospitalized patients on anticoagulant therapy. A prospective, observational cohort study was conducted in two Dutch hospitals. Adult patients hospitalized between October 2015 and October 2016 treated with anticoagulant therapy were included. Bleeding was defined as a composite endpoint of major bleeding and non-major bleeding according to the International Society on Thrombosis and Heamostasis (ISTH) criteria. Data analysis was performed by multivariate logistic regression.

RESULTS

The prevalence of in-hospital bleeding in patients using anticoagulant therapy was 7.2%; 95% confidence interval [95% CI] 5.5-9.1 (65 out of 906 patients). Multivariate logistic regression analysis indicated that female gender (adjusted odds ratio [ORadj] 2.1; 95% CI 1.2-3.7), high-bleeding-risk surgical procedure (ORadj 5.3; 95% CI 2.7-10.2), low-bleeding-risk surgical procedure (ORadj 4.9; 95% CI 1.9-12.6), and non-surgical interventions (ORadj 6.2; 95% CI 3.0-12.6) were associated with bleeding events in hospitalized patients treated with anticoagulants.

CONCLUSIONS

The prevalence of bleeding in anticoagulant users during hospitalization was 7.2%. This study detected potential risk factors that can help to identify patients on anticoagulants who have an increased risk of bleeding during hospitalization.

Health Care Costs and Utilization of Dabigatran Compared With Warfarin for Secondary Stroke Prevention in Patients With Nonvalvular Atrial Fibrillation: A Retrospective Population Study

BACKGROUND

It remains unclear whether the use of new oral anticoagulants, compared with warfarin, is economically beneficial in Asian countries.

OBJECTIVE

The objective of this study is to compare the health care costs and utilization between dabigatran and warfarin in a real-world nonvalvular atrial fibrillation (NVAF) population.

RESEARCH DESIGN

Data were obtained from the Taiwan National Health Insurance Database, and patients with an NVAF diagnosis between June 1, 2012, and May 31, 2014, were identified using the International Classification of Diseases, Ninth Revision code of 427.31. The patients in the dabigatran cohort were matched 1:2 to those in the warfarin cohort by sex, age, residential region, and a propensity score that incorporated a major bleeding history, CHADS2 score, and Charlson Comorbidity Index. The all-cause health care utilization and associated costs of the 2 treatment groups were compared at 3 and 12 months.

RESULTS

A total of 1149 patients taking dabigatran were identified and matched with 2298 warfarin users. During the 3-month observation period, the likelihood of having at least 1 hospitalization among dabigatran users was significantly lower than that of warfarin users (odds ratio=0.78; P=0.001). Patients in the dabigatran group incurred lower mean emergency department costs ($2383.1 vs. $3033.6), mean ischemic stroke-related hospitalization costs ($8869.5 vs. $13,990.5), and mean all-cause hospitalization costs ($32,402.2 vs. $50,669.9) at 3 months. However, both the mean and median outpatient costs of warfarin users were consistently lower than those of dabigatran users ($17,161.2 vs. $24,931.4 and $10,509.0 vs. $20,671.5, respectively). Similar trends were observed at 12 months, except that the 2 groups had comparable total health care costs.

CONCLUSIONS

The use of dabigatran is associated with lower emergency department and all-cause hospitalization costs but greater outpatient costs in a real-world, NVAF patient population compared with warfarin.

Deep Vein Thrombosis Prophylaxis after Total Hip Arthroplasty in Asian Patients

In Western patient populations, the reported incidence of imaging-demonstrated deep vein thrombosis (DVT) after total hip arthroplasty (THA) is as high as 70% without prophylaxis. The reported rates of symptomatic pulmonary embolism (PE) after THA in recent studies range from 0.6% to 1.5%, and the risk of fatal PE ranges from 0.11% to 0.19% in the absence of prophylaxis. Predisposing factors to DVT in western patients include advanced age, previous venous insufficiency, osteoarthritis, obesity, hyperlipidemia, dietary and genetic factors. However, Asian patients who have undergone THA have a strikingly low prevalence of DVT and virtually no postoperative PE. Some authors suggest low clinical prothrombotic risk factors and the absence of some DVT-related genetic factors in Asian patient populations decrease the risk of DVT, PE or both. In Korea, the prevalence of DVT after THA without thromboprophylaxis have ranges from 6.8% to 43.8%, and asymptomatic PE have ranges from 0% to 12.9%; there have been only two reported cases of fatal PE. Deep-wound infections resulting from postoperative hematomas or prolonged wound drainage have been reported with routine thromboprophylaxis. The prevalence of DVT differs varies based on patient ethnicity. Guidelines for the use of thromboprophylaxis were altered and focus on the potential value of outcomes compared with possible complications (e.g., bleeding).

Aesthetic Improvement of Undeveloped Calves After Treatment of Congenital Clubfoot Deformity

BACKGROUND

Even when clubfoot deformity is treated in a timely manner, the consequences observed in adulthood include hypoplasia of the calf muscles, gait impairment, decreases in foot size, and it can also affect the tibial length. These consequences may have negative impacts on the patient's subjective appraisal of long-term outcomes, and can influence the patient's self-esteem in both male and female patients.

OBJECTIVES

We present our experience in the treatment of undeveloped calves after surgical treatment of congenital clubfoot.

METHODS

In total, 72 patients underwent corrective surgery in order to improve undeveloped calves resulting from a congenital clubfoot deformity. We used calf silicone implants in combination with fat grafting in multistaged procedures, in order to decrease complication rates and improve aesthetic outcome.

RESULTS

Amongst our patients there were 54 (75%) females and 18 (25%) males. All of the patients, except one, had unilateral calf hypoplasia. The procedures were divided into several groups: (1) medial calf augmentation with silicone implants; (2) medial calf augmentation with silicone implants and fat grafting; and (3) medial and lateral calf augmentation with silicone implants and fat grafting. We had one case of a hyperpigmented scar and one case of partial scar dehiscence. There were no cases of compartment syndrome. The average follow-up period was 9.8 months.

CONCLUSIONS

Calf enhancement surgery in patients with congenital clubfoot deformity is very gratifying. When combining calf implants with fat grafting in multistaged procedures, we can achieve excellent results with low complication rates.

LEVEL OF EVIDENCE 4

Characteristics of patients with thromboembolic disorders on warfarin therapy in resource limited settings

Background

Warfarin is a drug with narrow therapeutic index used in the management of thromboembolic disorders. Several factors affect its plasma concentrations with a resultant risk of toxicity. We examined the database of patients on warfarin therapy in order to establish the factors that affect the stability of INR and correlated them to clinical outcomes in resource limited settings.

Methods

We analysed retrospective data of patients admitted to adult medical wards at Moi Teaching and Referral Hospital (MTRH) in 2015. Inclusion criteria were patients with thromboembolic and related disorders and on warfarin treatment. Derived data included demographics, indications for warfarin use, co-prescribed drugs, co-morbidities, INR measurements, duration of hospital stay and clinical outcomes. Descriptive statistics were used to summarize the data. Pearson’s correlation coefficient was used to assess relationships between duration of hospitalization and number of INR tests. Regression splines were used to capture INR trends during the follow up period. Data was analysed using R v. 3.3.1.

Results

A total of 310 patients had thromboembolic disorders, out of which 63 met the study criteria.

The median age was 48 years, while the mean number of INR measurements was once every four days. Majority of patients did not achieve stable INR values, with only two having consecutive INR values within therapeutic goal. Patients who died had high INR levels. The median duration of hospital stay was 9 days (IQR: 7.0, 16.5). There was a significant correlation between length of stay in hospital and the number of times that INR were measured (Corr = 0.667, p < 0.001). The two most common indications for warfarin were DVT (64.4%) and atrial fibrillation (24.7%). All the patients had one or more comorbid conditions except for 11 with DVT alone, with cardiovascular diseases and infections being the most frequent, and on concomitant medications, majority of which are known to interact with warfarin.

Conclusions

It was difficult to achieve stable INR under the prevailing conditions despite the frequent tests.

The potential factors that may have contributed to the fluctuations include drug-drug interactions, frequency of INR tests, comorbidities and the short duration of hospital stay.

Similar thromboprophylaxis with rivaroxaban and low molecular weight heparin but fewer hemorrhagic complications with combined intra-articular and intravenous tranexamic acid in total knee arthroplasty

PURPOSE

To evaluate the efficacy of the combined intravenous and intra-articular administration of tranexamic acid (TXA) to control the collateral effects and complications of rivaroxaban (RIV) after total knee arthroplasty (TKA) and to compare thromboprophylaxis schemes with and without TXA, RIV and low molecular weight heparin (LMWH).

MATERIALS AND METHODS

We prospectively studied 158 TKA patients from 2014 to 2018. The patients were randomly assigned into three groups. Group A (46 patients) was administered intravenous and intra-articular TXA and RIV postoperatively; group B (58 patients) was administered TXA as in group A and LMWH postoperatively; and group C (54 patients) was administered saline as in group A and RIV postoperatively. We evaluated blood loss, transfusion requirements and hemorrhagic complications.

RESULTS

Hct and Hb values significantly decreased in group C compared to groups A and B, without any difference between groups A and B. Suction drain blood volume output was significantly higher in group C compared to group A and B, without any difference between group A and B. Hemorrhagic complications were more common in group C. No patient experienced clinical findings of VTE.

CONCLUSION

Combined intravenous and intra-articular administration of TXA is safe and effective in TKA, with fewer hemorrhagic complications compared to placebo. Thromboprophylaxis with RIV and LMWH is similar.

Hematoma Expansion Following Intracerebral Hemorrhage: Mechanisms Targeting the Coagulation Cascade and Platelet Activation

Hematoma expansion (HE), defined as a greater than 33% increase in intracerebral hemorrhage (ICH) volume within the first 24 hours, results in significant neurological deficits, and enhancement of ICH-induced primary and secondary brain injury. An escalation in the use of oral anticoagulants has led to a surge in the incidences of oral anticoagulation-associated ICH (OAT-ICH), which has been associated with a greater risk for HE and worse functional outcomes following ICH. The oral anticoagulants in use include vitamin K antagonists, and direct thrombin and factor Xa inhibitors. Fibrinolytic agents are also frequently administered. These all act via differing mechanisms and thus have varying degrees of impact on HE and ICH outcome. Additionally, antiplatelet medications have also been increasingly prescribed, and result in increased bleeding risks and worse outcomes after ICH. Aspirin, thienopyridines, and GPIIb/IIIa receptor blockers are some of the most common agents in use clinically, and also have different effects on ICH and hemorrhage growth, based on their mechanisms of action. Recent studies have found that reduced platelet activity may be more effective in predicting ICH risk, hemorrhage expansion, and outcomes, than antiplatelet agents, and activating platelets may thus be a novel target for ICH therapy. This review explores how dysfunctions or alterations in the coagulation and platelet cascades can lead to, and/or exacerbate, hematoma expansion following intracerebral hemorrhage, and describe the mechanisms behind these effects and the drugs that induce them. We also discuss potential future therapy aimed at increasing platelet activity after ICH.

Bleeding and asymptomatic overdose in patients under Vitamin K antagonist therapy: Frequency and risk factors

Background

Vitamin K antagonists are widely used in the treatment and prevention of thromboembolic disease. However, these drugs can cause serious side effects, especially bleeding. This study aims to evaluate frequency and risk factors of both bleeding and asymptomatic overdose in North African patients undergoing Vitamin K antagonist therapy.

Methods

We performed a cross-sectional study in patients undergoing Vitamin K antagonist therapy. A statistical analysis has been conducted to identify overdose and bleeding risk factors by using chi-square test (p < .05).

Results

One hundred and eleven patients were included. We recorded 14 cases of bleeding and 26 cases of asymptomatic overdose. Advanced age, poor adherence, concomitant use of paracetamol and history of previous bleeding are significant risk factors of over-anticoagulation. An INR value over 6 at admission, a high therapeutic target range for INR, concomitant use of acetylsalicylic acid, lack of information on overdose signs and measures to be taken in case of bleeding were identified as risk factors for bleeding.

Conclusion

Most of the risk factors identified in our study seem to be related to patients lack of information and education. These results highlight the importance of creating a therapeutic patient education program.

Topical Tranexamic Acid Reduces Blood Loss in Minimally Invasive Total Knee Arthroplasty Receiving Rivaroxaban

Background

It is unclear whether topical (intra-articular) or intravenous TXA reduces blood loss in minimally invasive TKA patients receiving a direct oral anticoagulant for thromboprophylaxis. This study is to investigate whether TXA given intravenously or intra-articularly is effective in reducing blood loss in minimally invasive TKA patients using rivaroxaban for thromboprophylaxis.

Methods

Ninety-three patients who underwent primary minimally invasive TKA were divided into placebo group (30 patients) that received saline both intravenously and intra-articularly, intravenous (IV) group (31 patients) that received 1 g TXA intravenously, and topical group (32 patients) that received 3 g TXA in 100 ml saline intra-articularly. All patients received oral rivaroxaban of 10 mg daily for 14 days postoperatively.

Results

p < 0.001 and p = 0.041. The mean total blood loss was 1131 mL (567–1845) in placebo, which was higher than that in the IV group (921 mL; range, 465–1495; p = 0.014) and the topical group (795 mL; range, 336–1350; p < 0.001). The total blood loss did not differ between the IV and the topical group (p = 0.179).

Conclusion

This prospective, randomized, controlled trial demonstrated an equal efficacy of TXA in blood conservation when administered intravenously or topically in minimally invasive TKA patients receiving rivaroxaban for thromboprophylaxis.

Two novel inhibitory anti-human factor XI antibodies prevent cessation of blood flow in a murine venous thrombosis model

Coagulation factor XI (FXI) is a promising target for anticoagulation, because of its major role in thrombosis and relatively minor role in haemostasis. This implies that inhibition of FXI can prevent thrombosis without causing bleeding. It was our aim to investigate the antithrombotic properties of two novel inhibitory anti-human FXI antibodies (αFXI-175 and αFXI-203). The in vitro properties of both antibodies were analysed using standard clotting assays and calibrated automated thrombography. For the in vivo model we used FXI knockout mice, in which FXI plasma levels were restored with purified human FXI. Thrombosis was induced by applying ferric chloride to the vena cava inferior, after which time to occlusion was analysed. A tail bleeding assay was used to investigate the safety of both antibodies. Using calibrated automated thrombography, both antibodies inhibited thrombin generation initiated via the intrinsic pathway. In contrast, upon tissue factor (TF)-initiated thrombin generation, αFXI-203 did not inhibit thrombin generation, while αFXI-175 inhibited thrombin generation only at low concentrations of TF. In the murine thrombosis model, the vena cava inferior remained patent for 25 minutes (min) in mice treated with αFXI-175 and for 12.5 min in αFXI-203 treated animals, which was significantly longer than in placebo-treated animals (5 min, p<0.05). Neither antibody caused severe blood loss in a tail bleeding assay. In conclusion, the two inhibitory antibodies against FXI prevented cessation of blood flow in a murine thrombosis model without inducing a bleeding tendency.

Reversal of rivaroxaban anticoagulation by haemostatic agents in rats and primates

Rivaroxaban is an oral, direct factor Xa inhibitor for the management of thromboembolic disorders. Despite its short half-life, the ability to reverse rivaroxaban anticoagulation could be beneficial in life-threatening emergencies. The potential of prothrombin complex concentrate (PCC; Beriplex®), activated PCC (aPCC; FEIBA®) or recombinant activated factor VII (rFVIIa; NovoSeven®) to reverse rivaroxaban in rats and baboons was investigated. Anaesthetised rats pre-treated with intravenous rivaroxaban (2 mg/kg) received intravenous rFVIIa (100/400 μg/kg), PCC (25/50 U/kg) or aPCC (50/100 U/kg) after initiation of bleeding. Clotting times and bleeding times (BTs) were recorded. Rivaroxaban was administered as an intravenous 0.6 mg/kg bolus followed by continuous 0.6 mg/kg/hour infusion in baboons. Animals received intravenous aPCC 50 U/kg (2 U/kg/minute) or rFVIIa 210 μg/kg. BT and clotting parameters were measured. In rats pre-treated with high-dose rivaroxaban, PCC 50 U/kg, aPCC 100 U/kg and rFVIIa 400 μg/kg significantly reduced BT vs rivaroxaban alone (5.4 ± 1.4-fold to 1.5 ± 0.4-fold [p<0.05]; 3.0 ± 0.4-fold to 1.4 ± 0.1-fold [p<0.001]; and 3.5 ± 0.7-fold to 1.7 ± 0.2-fold [p<0.01] vs baseline, respectively). In baboons pre-infused with rivaroxaban and then given aPCC, BT increased by 2.0 ± 0.2-fold and aPCC returned BT to baseline for the duration of its infusion. rFVIIa reduced BT from 2.5 ± 0.3-fold over baseline to 1.7 ± 0.3-fold over baseline. Prolongation of prothrombin time was reduced by PCC, aPCC and rFVIIa in both species. Rivaroxaban reduced thrombin-antithrombin levels; application of PCC and aPCC, but not rFVIIa, increased these levels. In conclusion, PCC, aPCC or rFVIIa have the potential to reverse the anticoagulant and anti-haemostatic effects of rivaroxaban.

Reversal of anticoagulant effects of edoxaban, an oral, direct factor Xa inhibitor, with haemostatic agents

Edoxaban, an oral, direct factor Xa inhibitor, has a similar or low incidence of bleeding events compared with other anticoagulants in clinical trials. Therefore, agents to reverse the anticoagulant effects of edoxaban could be desirable in emergency situations. In this study, the reversal effects of haemostatic agents were determined on prothrombin time (PT) prolongation in vitro and bleeding time prolongation in vivo by edoxaban. PT using human plasma was measured in the presence of edoxaban at therapeutic and excess concentrations with the haemostatic agents, prothrombin complex concentrate (PPSB-HT), activated prothrombin complex concentrate (Feiba), and recombinant factor VIIa (rFVIIa). In rats, rFVIIa and Feiba was given during intensive anticoagulation with edoxaban. The haemostatic effect was evaluated in a model of planta template bleeding and a potential prothrombotic effect was evaluated in a venous thrombosis model. PPSB-HT, Feiba, and rFVIIa concentration-dependently shortened PT prolonged by edoxaban. Among these, rFVIIa and Feiba showed potent activities in reversing the PT prolongation by edoxaban. rFVIIa (1 and 3 mg/kg, i.v.) and Feiba (100 U/kg, i.v.) significantly reversed edoxaban (1 mg/kg/h)-induced prolongation of bleeding time in rats. In a rat venous thrombosis model, no potentiation of thrombus formation was observed when the highest dose (3 mg/kg) of rFVIIa was added to edoxaban (0.3 and 1 mg/kg/h) compared with the control. The present study indicated that rFVIIa, Feiba, and PPSB-HT have the potential to be reversal agents for edoxaban.

New oral anticoagulants in venous thromboembolism prophylaxis in orthopaedic patients: Are they really better?

Prophylaxis against venous thromboembolism (VTE) is considered standard of care. Appropriate chemoprophylaxis for VTE has been mandated by the United States government agencies and consumer groups. However, controversies exist regarding the most clinically relevant and safe chemoprophylaxis protocols in patients undergoing joint replacement surgery. Thus, this paper reviews the clinical efficacy and safety of newer oral anticoagulants. A literature search was performed for oral anticoagulants in advanced stages of development using PubMed and abstracts from thrombosis meetings. Most clinical trial data have demonstrated equal or superior efficacy in venographic endpoints in comparison to low-molecular-weight heparins (LMWH). However, bleeding complications have been reported to occur with oral anticoagulants as frequently as or more frequently than with LMWH. Other potential complications reported include liver enzyme elevation and cardiac irregularities. It remains to be established whether newer oral anticoagulants will be better alternatives to the current standard-ofcare in real-life medical clinical practice.