Treatment of bleeding complications in patients on anticoagulant therapy

Radiological findings in poisoning by synthetic cannabinoids adulterated with brodifacoum

OBJECTIVES

Severe coagulopathy due to consumption of synthetic cannabinoids adulterated with brodifacoum, a long-acting anticoagulant, is an emerging worldwide hazard. Here, we review the spectrum of imaging findings in adulterated cannabinoid poisoning.

MATERIALS AND METHODS

In this retrospective study, we used the Israeli Poison Information Center database to identify patients with cannabinoid-associated coagulopathy who presented to the Rambam Health Care Campus, where most patients were treated during an outbreak in northern Israel between September 2021 and June 2022. All relevant imaging studies for these patients were reviewed. We estimated the sensitivity of findings for cannabinoid-associated coagulopathy. Associations between a continuous variable and a dichotomous outcome were assessed with the Mann-Whitney U test.

RESULTS

We identified 48 patients (mean age 40 years ± 9 [SD], 43 males) with 54 hospitalizations due to cannabinoid-associated coagulopathy. Symptomatic hemorrhage was documented in 50 (93%) cases at presentation, most of whom (78%) had hemorrhage from multiple systems. The most common bleeding site was the genitourinary collecting system, with a characteristic sign of suburothelial bleeding in 16/18 of performed abdominal CTs (sensitivity 89% [CI 65-99%] for cannabinoid-associated coagulopathy). Intramural bowel hematomas were noted in 70% (7/10) of CTs of patients with gastrointestinal bleeding. Incidental bleeding sites were identified on imaging in 24% of patients. An increased number of bleeding sites was associated with need for vasopressors (difference in bleeding sites 3.00 [95% CI 0.99-4.00], p = 0.026).

CONCLUSION

CT plays a key role in the diagnosis and work-up of adulterated cannabinoid-associated coagulopathy. Characteristic signs include suburothelial hemorrhage and intramural bowel hematomas.

CLINICAL RELEVANCE STATEMENT

Recognition of radiological signs of adulterated synthetic cannabinoid-associated coagulopathy is critical for optimizing outbreak control on the public health level and ensuring timely treatment on the individual patient level.

KEY POINTS

• Severe coagulopathy due to consumption of synthetic cannabinoids adulterated with brodifacoum, a long-acting anticoagulant, is an emerging worldwide threat. • Characteristic imaging signs include suburothelial bleeding, intramural bowel hematomas, and rare incidental bleeding sites. • Imaging has a pivotal role in optimizing outbreak control and ensuring timely and appropriate treatment.

The risk of hemorrhagic complications after anticoagulation therapy in trauma patients: A multicenter evaluation

BACKGROUND

The use of anticoagulation therapy (ACT) in trauma patients during the postinjury period presents a challenge given the increased risk of hemorrhage. Guidelines regarding whether and when to initiate ACT are lacking, and as a result, practice patterns vary widely. The purpose of this study is to describe the incidence of hemorrhagic complications in patients who received ACT during their hospitalization, identify risk factors, and characterize the required interventions.

METHODS

In this retrospective cohort study, all trauma admissions at two Level I trauma centers between January 2015 and December 2020 were reviewed. Patients with preexisting ACT use or those who developed a new indication for ACT were included for analysis. Demographic and outcome data were collected for those who received ACT during their admission. Comparisons were then made between the complications and no complications groups. A subgroup analysis was performed for all patients started on ACT within 14 days of injury.

RESULTS

A total of 812 patients were identified as having an indication for ACT, and 442 patients received ACT during the postinjury period. The overall incidence of hemorrhagic complications was 12.7%. Of those who sustained hemorrhagic complications, 18 required procedural intervention. On regression analysis, male sex, severe injuries, and the need for hemorrhage control surgery on arrival were all found to be associated with hemorrhagic complications after the initiation of ACT. Waiting 7 days to 14 days from the time of injury to initiate ACT reduced the odds of complications by 46% and 71%, respectively.

CONCLUSION

The use of ACT in trauma during the postinjury period is not without risk. Waiting 7 days to 14 days postinjury might greatly reduce the risk of hemorrhagic complications.

LEVEL OF EVIDENCE

Therapeutic/Care Management Study; Level IV.

A systematic review and meta-analysis of the effectiveness of primary thromboprophylaxis in acute lymphoblastic leukemia during early-phase therapy including asparaginase or its prolonged form

Asparaginase is essential in the initial management of acute lymphoblastic leukemia (ALL) but frequently leads to venous thromboembolism (VTE). Using anticoagulants for primary VTE prevention has been studied with no consensus. We conducted a systematic literature search in PubMed, Scopus, and Web of science and performed random-effect meta-analysis using Mantel-Haenszel method in RevMan 5.4 to analyze primary pharmacological thromboprophylaxis during asparaginase treatment in early-phase (induction, consolidation, or intensification phase) therapy in patients with ALL with all ages and followed with subgroup analysis by age. Meta-analysis of 13 articles describing the effect of antithrombin supplementation in 1375 patients showed that antithrombin prophylaxis decreases the risk of VTE by 43% (RR, 0.57; 95% CI, 0.38 - 0.83; p=0.004), with mild heterogeneity (I2=35%, p=0.10) and moderate certainty by GRADE. 8 articles included for meta-analysis of low-molecular weight heparin (LMWH) treatment in 612 patients showed that it decreased the risk of VTE by nearly 40% (RR, 0.61; 95% CI, 0.45 - 0.81; p=0.00081), with minimal heterogeneity (I2=14%, p=0.31) but low certainty. Subgroup analysis showed that only prophylaxis with antithrombin supplementation significantly decreased the VTE rate in adult patients with moderate certainty. In pediatric patients, one nonrandomized prospective study showed that LMWH combined with antithrombin has a better thromboprophylaxis effect than antithrombin alone. In the PREVAPIX-ALL trial, prophylaxis with direct factor Xa inhibitor Apixaban did not benefit children younger than 18 years except for cases of obesity. We concluded that thromboprophylaxis with antithrombin is effective in ALL patients older than 18 years during the early phase of therapy, and LMWH combined with antithrombin supplementation might be effective for pediatric patients with ALL. Apixaban is effective in pediatric ALL patients with obesity and needs further study in other high-risk patients.

Reversal and resumption of anticoagulants in patients with anticoagulant-associated intracerebral hemorrhage

The use of anticoagulants has become more frequent due to the progressive aging population and increased thromboembolic events. Consequently, the proportion of anticoagulant-associated intracerebral hemorrhage (AAICH) in stroke patients is gradually increasing. Compared with intracerebral hemorrhage (ICH) patients without coagulopathy, patients with AAICH may have larger hematomas, worse prognoses, and higher mortality. Given the need for anticoagulant reversal and resumption, the management of AAICH differs from that of conventional medical or surgical treatments for ICH, and it is more specific. Understanding the pharmacology of anticoagulants and identifying agents that can reverse their effects in the early stages are crucial for treating life-threatening AAICH. When patients transition beyond the acute phase and their vital signs stabilize, it is important to consider resuming anticoagulants at the right time to prevent the occurrence of further thromboembolism. However, the timing and strategy for reversing and resuming anticoagulants are still in a dilemma. Herein, we summarize the important clinical studies, reviews, and related guidelines published in the past few years that focus on the reversal and resumption of anticoagulants in AAICH patients to help implement decisive diagnosis and treatment strategies in the clinical setting.

Maxillofacial haemorrhagic symptoms in emergency department patients: impact of antithrombotics

PURPOSE

To investigate the effect of antithrombotics on the occurrence of maxillofacial haemorrhagic symptoms, and to determine if these haemorrhagic symptoms are predictors of maxillofacial fractures.

METHOD

A prospective cohort study was conducted of consecutive patients with maxillofacial trauma who had been admitted to the emergency department of four hospitals in the Netherlands. This study compared five haemorrhagic symptoms (peri-orbital haematoma, raccoon eyes, epistaxis, subconjunctival ecchymosis, and intra-oral haematoma) between patients not-using (NUA) and using (UA) of antithrombotics, and whether these maxillofacial haemorrhagic symptoms served as predictors for maxillofacial fractures.

RESULTS

Out of the 1005 patients, 812 (81%) belonged to the NUA group, and 193 (19%) to the UA group. UA patients exhibited higher frequencies of peri-orbital hematoma (54% vs. 39%, p < 0.001), raccoon eyes (10% vs. 5%, p = 0.01), and subconjunctival ecchymoses (16% vs. 7%, p < 0.001). In NUA, peri-orbital hematoma (OR = 2.5, p < 0.001), epistaxis (OR = 4.1, p < 0.001), subconjunctival ecchymosis (OR = 2.3, p = 0.02), and intra-oral hematoma (OR = 7.1, p < 0.001) were significant fracture predictors. Among UA, peri-orbital hematoma (OR = 2.2, p = 0.04), epistaxis (OR = 5.4, p < 0.001), subconjunctival ecchymosis (OR = 3.7, p = 0.008), and intra-oral hematoma (OR = 22.0, p < 0.001) were significant fracture predictors.

CONCLUSION

Maxillofacial haemorrhagic symptoms were observed more frequently in the UA group than in the NUA group. However, in both groups, maxillofacial haemorrhagic symptoms appear to be predictors of maxillofacial fractures. Caution is warranted in attributing these symptoms solely to antithrombotic use during emergency department assessments.

Hemorrhage induced by antithrombotic agents: new insights from a real-world pharmacovigilance study

BACKGROUND

Hemorrhage represents the most common and serious side effect of antithrombotic agents. Many studies have compared the risk of bleeding between different antithrombotic agents, but analysis of time-to-onset for hemorrhage induced by these drugs is yet sparse.

METHODS

We conducted a retrospective study based on the adverse drug reaction reports on antithrombotic agents collected by the Henan Adverse Drug Reaction Monitoring Center. We assessed the reporting odds ratio to determine the disproportionate reporting signals for bleeding and the Weibull shape parameter was used to evaluate the time-to-onset data.

RESULTS

In the signal detection, crude low molecular weight heparin-hemorrhage was found as a positive signal. The hemorrhage for most antithrombotic agents was random failure profiles. In particular, the hazard of hemorrhage decreased over time for warfarin and clopidogrel and increased for alteplase, nadroparin, and dipyridamole.

CONCLUSION

We found that the risk of bleeding in patients taking Crude low molecular weight heparins was significantly higher compared to other antithrombotic agents, but with a small magnificence, which may be attributed to the severely irrational use of this medication under improper management. Statistics in days, results showed that the risk of bleeding decreased over time for warfarin and clopidogrel and increased for alteplase, nadroparin, and dipyridamole.

Safety and efficacy of fixed versus variable-dose prothrombin complex concentrate for emergent reversal of vitamin K antagonists: A systematic review and meta-analysis

STUDY OBJECTIVE

Four-factor prothrombin complex concentrate (4F-PCC) is standard of care for emergent vitamin K antagonist (VKA) reversal but optimal dosing is uncertain. This meta-analysis estimated the proportion of patients treated with fixed dose (FD) 4F-PCC who achieved adequate reversal and compared safety and efficacy of FD versus weight-based dose (WB) strategies.

METHODS

This review was conducted according to PRISMA guidelines. Medline and Scopus were searched and included studies evaluating FD regimens and comparing FD and WB for emergent VKA reversal. Data was pooled using random effects. Subgroup analyses examined heterogeneity. Risk of bias was assessed with Newcastle-Ottawa Scale and RoB2 score.

RESULTS

Twenty-three studies (n = 2055) were included with twelve (n = 1143) comparing FD versus WB. The proportion of patients achieving goal INR with FD varied depending on the INR target, being significantly higher for INR <2 (90.9%, 95% Confidence Interval (CI) 87.2, 94.06) compared to INR <1.6 (70.97%, 95%CI 65.33, 76.31). Compared to WB, FD was less likely to achieve a goal INR <1.6 (Risk Difference (RD) -13%, 95% CI -21, -4) but achieved similar reversal for a goal INR <2.0, (RD -1%, 95%CI -7, 4). There was no difference in hospital mortality (RD 4%, 95%CI -2, 9) or thrombosis (RD 0.0%, 95%CI -3, 3).

CONCLUSION

FD VKA reversal was associated with significantly lower attainment of goal INR compared to WB with lower INR targets. This did not translate to differences in hospital mortality, but these results should be interpreted cautiously in light of the observational nature of the included studies.

Anti-thrombotic Effects Mediated by a Novel Dual-Target Peptide Inhibiting Both Platelet Aggregation and Thrombin Activity without Causing Bleeding

BACKGROUND

 Classical anticoagulants and antiplatelets are associated with high frequencies of bleeding complications or treatment failure when used as single agents. Thrombin plays an important role in the blood coagulation system. GP IIb/IIIa is the central receptor of platelets, which can recognize the Arg-Gly-Asp (RGD) sequence and activate platelets.

MATERIAL AND METHODS

 Molecular simulation and homology modeling were performed to design a novel dual-target anticoagulant short peptide (PTIP ). The activities of PTIP on coagulation and platelet in vitro were analyzed. The antithrombotic activity of PTIP was determined by pulmonary thromboembolism model, ferric chloride injury model and arteriovenous bypass thrombosis model. Bleeding effect and toxicity of PTIP were evaluated.

RESULTS

 We have constructed a novel dual-target peptide (PTIP) based on the direct thrombin inhibitor peptide (DTIP). PTIP was expressed at high levels in Pichia pastoris. PTIP interfered with thrombin-mediated coagulation and ADP-induced platelet aggregation in vitro. When injected intravenously or subcutaneously, PTIP showed potent and dose-dependent extension of aPTT and PT which were similar to DTIP; but only PTIP was capable of inhibiting platelet aggregation. PTIP (1.0 mg/kg) decelerated thrombosis formation in venous and arterial vessels induced by FeCl3 injury. PTIP (1.0 mg/kg) also prevented deep venous thrombosis and increased the survival rate associated with pulmonary thromboembolism. And PTIP effectively reduced thrombus length in arteriovenous bypass thrombosis model. Moreover, the antithrombotic dose of PTIP could not induce bleeding.

CONCLUSION

 These data establish that PTIP represents a novel antithrombotic agent whose effects involve both inhibition of platelet activation and reduction of fibrin generation. And PTIP not only can be used in venous thrombosis and arterial thrombosis, it can also replace the combined treatment of antiplatelet and anticoagulant drugs in thrombotic diseases.

Uncontrolled Arterial Bleeding in a Patient With Massive Right Calf Hematoma: A Case Report and a Review of the Literature

A hematoma is a collection of pooled blood that can be confined to a space under the skin, tissue, or organ. It occurs due to injury to the vasculature arising from trauma, previous surgeries, or vascular defects. Anticoagulants can remarkably increase a patient's risk for hematoma formation. Most hematomas will resolve spontaneously over time, but there are certain instances where surgical intervention becomes necessary. We present a case of a 71-year-old female on anticoagulants who presented to the emergency department (ED) with an expanding hematoma on her right leg after a fall and had to undergo an emergency surgical evacuation. The etiology, appropriate management, and complications of hematomas will also be covered in this paper.

Bivalirudin vs heparin in cardiac-cerebral ischemic and bleeding events among Chinese STEMI patients during percutaneous coronary intervention: a retrospective cohort study

Although bivalirudin has been recently made available for purchase in China, large-scale analyses on the safety profile of bivalirudin among Chinese patients is lacking. Thus, this study aimed to compare the safety profile of bivalirudin and heparin as anticoagulants in Chinese ST-segment elevation myocardial infarction (STEMI) patients undergoing percutaneous coronary intervention (PCI). A total of 1063 STEMI patients undergoing PCI and receiving bivalirudin (n=424, bivalirudin group) or heparin (n=639, heparin group) as anticoagulants were retrospectively enrolled. The net adverse clinical events (NACEs) within 30 days after PCI were recorded, including major adverse cardiac and cerebral events (MACCEs) and bleeding events (bleeding academic research consortium (BARC) grades 2-5 (BARC 2-5)). The incidences of NACEs (10.1 vs 15.6%) (P=0.010), BARC 2-5 bleeding events (5.2 vs 10.3%) (P=0.003), and BARC grades 3-5 (BARC 3-5) bleeding events (2.1 vs 5.5%) (P=0.007) were lower in the bivalirudin group compared to the heparin group, whereas general MACCEs incidence (8.9 vs 6.4%) (P=0.131) and each category of MACCEs (all P>0.05) did not differ between two groups. Furthermore, the multivariate logistic analyses showed that bivalirudin (vs heparin) was independently correlated with lower risk of NACEs (OR=0.508, P=0.002), BARC 2-5 bleeding events (OR=0.403, P=0.001), and BARC 3-5 bleeding events (OR=0.452, P=0.042); other independent risk factors for NACEs, MACCEs, or BARC bleeding events included history of diabetes mellitus, emergency operation, multiple lesional vessels, stent length >33.0 mm, and higher CRUSADE score (all P<0.05). Thus, bivalirudin presented a better safety profile than heparin among Chinese STEMI patients undergoing PCI.

Intracerebral hemorrhage mortality in individuals with atrial fibrillation: a nationwide analysis of mortality trends in the United States

BACKGROUND

Atrial fibrillation (AF) is a risk factor for intracerebral hemorrhage (ICH), both with and without use of anticoagulation. Limited data exists on mortality trends and disparities related to this phenomenon. We aimed to assess ICH mortality trends and disparities based on demographic factors in individuals with atrial fibrillation in the United States (US).

METHODS

Our cross-sectional analysis utilized mortality data from the CDC database through death certificate queries from the years 1999 to 2020 in the US. We queried for all deaths with ICH as the underlying cause of death and atrial fibrillation as the multiple causes of death. Mortality data was obtained for overall population and demographic subpopulations based on sex, race and ethnicity, and geographic region. Trend analysis and average annual-mortality percentage change (AAPC) were completed using log-linear regression models.

RESULTS

ICH age-adjusted mortality rate (AAMR) in patients with AF increased from 0.27 (95% CI 0.25-0.29) in 1999 to 0.30 (95% CI 0.29-0.32) in 2020. A higher mortality rate was observed in males (AAMR 0.33) than in females (AAMR 0.26). The highest mortality was found in Asian/Pacific Islander (AAMR: 0.32) populations, followed by White (AAMR: 0.30), Black (AAMR: 0.15), and American Indian/Alaska Native (AAMR: 0.11) populations. Southern (AAPC: 1.3%) and non-metropolitan US regions (AAPC: + 1.9%) had the highest increase in annual mortality change.

CONCLUSION

Our findings highlight the disparities in ICH mortality in patients with AF. Further investigation is warranted to confirm these findings and evaluate for contributors to the observed disparities.

Direct oral anticoagulants or vitamin K antagonists in emergencies: comparison of management in an observational study

Background

Restoring hemostasis in patients on oral anticoagulants presenting with major hemorrhage (MH) or before surgical intervention has changed, with the replacement of vitamin K antagonist (VKA) with direct oral anticoagulants (DOACs).

Objectives

To observe the difference in urgent hemostatic management between patients on VKA and those on DOACs.

Methods

A multicenter observational study evaluated the variation in laboratory testing, hemostatic management, mortality, and hospital length of stay (LOS) in patients on VKA or DOACs presenting with MH or urgent hemostatic restoration.

Results

Of the 1194 patients analyzed, 783 had MH (61% VKA) and 411 required urgent hemostatic restoration before surgery (56% VKA). Compared to the international normalized ratio (97.6%), plasma DOAC levels were measured less frequently (<45%), and the time taken from admission for the coagulation sample to reach the laboratory varied widely (median, 52.3 minutes; IQR, 24.8-206.7). No significant plasma DOAC level (<50 ng/mL) was found in up to 19% of patients. There was a poor relationship between plasma DOAC level and the usage of a hemostatic agent. When compared with patients receiving VKA (96.5%) or dabigatran (93.7%), fewer patients prescribed a factor Xa inhibitor (75.5%) received a prohemostatic reversal agent. The overall 30-day mortality for MH (mean: 17.8%) and length of stay (LOS) (median: 8.7 days) was similar between VKA and DOAC patients.

Conclusion

In DOAC patients, when compared to those receiving VKA, plasma DOAC levels were measured less frequently than the international normalized ratio and had a poor relationship with administering a hemostatic reversal agent. In addition, following MH, mortality and LOS were similar between VKA and DOAC patients.

Case report: Spontaneous hemothorax following anticoagulation for microthrombi in severe COVID pneumonia

Background

Anticoagulant therapy has become a hallmark of treatment for critically ill COVID patients. Gastrointestinal and intracranial hemorrhage are known major complications of anticoagulation, but spontaneous hemothorax is a rare event, particularly in the absence of pre-existing structural lung disease, vascular malformations, or genetic bleeding diatheses. Herein is a case of spontaneous hemothorax following anticoagulation for microthrombi in a patient with acute hypoxic respiratory failure due to Covid pneumonia.

Case presentation

A 49 year old male with hypertension, asthma, and obesity was admitted for acute hypoxic respiratory failure due to Covid pneumonia. He was treated with dexamethasone, baricitinib, and therapeutic enoxaparin as empiric therapy for severe COVID disease. He subsequently developed a massive right hemothorax with associated hemorrhagic shock, which required initiation of massive transfusion protocol, vasopressor support and mechanical ventilation. No clear etiology for the hemothorax was determined upon investigations. The patient eventually improved and was discharged to a skilled nursing facility on chronic oxygen therapy.

Conclusions

Various mechanisms have been proposed for the development of non-traumatic hemothoraces, including tearing of adhesions and rupture of vascularized bullae. Such explanations find support in radiologic and pathologic studies of pleural changes in Covid pneumonia, and likely played a role in the hemorrhage experienced by our patient.

OKL-1111, A modified cyclodextrin as a potential universal reversal agent for anticoagulants

BACKGROUND

Antithrombotic therapy is inevitably associated with a risk for bleeding and these bleeding complications can be life-threatening. Recently, specific reversal agents were developed for the direct factor Xa and thrombin inhibitors (DOACs). However, next to the fact that these agents are relatively expensive, the use of selective reversal agents complicates treatment of bleeding patients in practice. In a series of screening experiments, we discovered a class of cyclodextrins with procoagulant properties. In this study we characterize a lead compound, OKL-1111, and demonstrate its potential use as a universal reversal agent.

OBJECTIVES

To assess the anticoagulant reversal properties of OKL-1111, in vitro and in vivo.

METHODS

The effect of OKL-1111 on coagulation in the absence and presence of DOACs was investigated in a thrombin generation assay. Its reversal effect on a variety of anticoagulants in vivo was investigated in a rat tail cut bleeding model. A possible prothrombotic action of OKL-1111 was assessed in a Wessler model in rabbits.

RESULTS

OKL-1111 concentration-dependently reversed the in vitro anticoagulant effects of dabigatran, rivaroxaban, apixaban and edoxaban in the thrombin generation assay. Also in the absence of a DOAC, OKL-1111 concentration-dependently accelerated coagulation in this assay, but did not initiate coagulation. The reversal effect was also seen for all DOACs in the rat tail cut bleeding model. In addition, when tested with other anticoagulants, OKL-1111 also reversed the anticoagulant effect of the vitamin K antagonist warfarin, the low molecular weight heparin enoxaparin, the pentasaccharide fondaparinux and the platelet inhibitor clopidogrel in vivo. OKL-1111 did not have prothrombotic effects in the Wessler model.

CONCLUSION

OKL-1111 is a procoagulant cyclodextrin with a currently unknown working mechanism that has potential to become a universal reversal agent for anticoagulants and platelet inhibitors.

A versatile modification strategy for functional non-glutaraldehyde cross-linked bioprosthetic heart valves with enhanced anticoagulant, anticalcification and endothelialization properties

Valvular heart disease is a major threat to human health and transcatheter heart valve replacement (THVR) has emerged as the primary treatment option for severe heart valve disease. Bioprosthetic heart valves (BHVs) with superior hemodynamic performance and compressibility have become the first choice for THVR, and more BHVs have been requested for clinical use in recent years. However, several drawbacks remain for the commercial BHVs cross-linked by glutaraldehyde, including calcification, thrombin, poor biocompatibility and difficulty in endothelialization, which would further reduce the BHVs' lifetime. This study developed a dual-functional non-glutaraldehyde crosslinking reagent OX-VI, which can provide BHV materials with reactive double bonds (CC) for further bio-function modification in addition to the crosslinking function. BHV material PBAF@OX-PP was developed from OX-VI treated porcine pericardium (PP) after the polymerization with 4-vinylbenzene boronic acid and the subsequent modification of poly (vinyl alcohol) and fucoidan. Based on the functional anti-coagulation and endothelialization strategy and dual-functional crosslinking reagent, PBAF@OX-PP has better anti-coagulation and anti-calcification properties, higher biocompatibility, and improved endothelial cells proliferation when compared to Glut-treated PP, as well as the satisfactory mechanical properties and enhanced resistance effect to enzymatic degradation, making it a promising candidate in the clinical application of BHVs. STATEMENT OF SIGNIFICANCE: Transcatheter heart valve replacement (THVR) has become the main solution for severe valvular heart disease. However, bioprosthetic heart valves (BHVs) used in THVR exhibit fatal drawbacks such as calcification, thrombin and difficulty for endothelialization, which are due to the glutaraldehyde crosslinking, resulting in a limited lifetime to 10-15 years. A new non-glutaraldehyde cross-linker OX-VI has been designed, which can not only show great crosslinking ability but also offer the BHVs with reactive double bonds (CC) for further bio-function modification. Based on the dual-functional crosslinking reagent OX-VI, a versatile modification strategy was developed and the BHV material (PBAF@OX-PP) has been developed and shows significantly enhanced anticoagulant, anti-calcification and endothelialization properties, making it a promising candidate in the clinical application of BHVs.

The risk of major bleeding in patients with factor V Leiden or prothrombin G20210A gene mutation while on extended anticoagulant treatment for venous thromboembolism

BACKGROUND

Thrombophilia predisposes to venous thromboembolism (VTE) because of acquired or hereditary factors. Among them, it has been suggested that gene mutations of the factor V Leiden (FVL) or prothrombin G20210A mutation (PGM) might reduce the risk of bleeding, but little data exist for patients treated using anticoagulants.

OBJECTIVES

To assess whether thrombophilia is protective against bleeding.

METHODS

This multicentre, multinational, prospective cohort study evaluated adults receiving long-term anticoagulants after a VTE event. We analyzed the incidence of major bleeding as the primary outcome, according to the genotype for FVL and PGM (wild-type and heterozygous/homozygous carriers).

RESULTS

Of 2260 patients with genotype testing, during a median follow-up of 3 years, 106 patients experienced a major bleeding event (17 intracranial and 7 fatal). Among 439 carriers of FVL, 19 experienced major bleeding and there were no differences between any mutation vs wild-type (hazard ratio [HR], 0.89 [0.53-1.49]; p = .66). The comparison of major bleeding events between the 158 patients with any-PGM mutation (heterozygous or homozygous) vs wild-type also showed a nonstatistically significant difference with HR of 0.53 (0.19-1.43), p = .21. However, multivariate analysis demonstrated that major bleeds or clinically relevant nonmajor bleeding were statistically less likely for patients with either FVL and/or PGM compared with patients with both wild-type factor V and prothrombin genes (HR, 0.73; 95% CI = 0.55-0.97; p = .03).

CONCLUSION

This study demonstrates that thrombophilia, defined as the presence of either FVL or the prothrombin G20210A mutation, is related with a lower rate of major/clinically relevant nonmajor bleeding while on anticoagulants in the extended treatment for VTE.

Case Report: Spontaneous Left Inferior Epigastric Artery Injury in a COVID-19 Female Patient Undergoing Anticoagulation Therapy

Since the beginning of the pandemic, a recommendation was made for the use of anticoagulants in high-risk hospitalized patients. This therapeutic approach has positive and negative effects regarding the outcome of the disease. Anticoagulant therapy prevents thromboembolic events, but it can also lead to spontaneous hematoma formation, or be accompanied by massive active bleeding. We present a 63-year-old COVID-19-positive female patient with a massive retroperitoneal hematoma and spontaneous left inferior epigastric artery injury.

A cysteine enzyme hemostat for efficient heparin-tolerant blood coagulation

It is challenging to stop bleeding effectively in patients treated with heparin which leads to enhanced risk of uncontrolled bleeding during operation. Herein, we report an easy-to-use and heparin-tolerant hemostatic agent based on a thrombin-like cysteine enzyme (papain), which catalyzes the hydrolysis of fibrinogen and cross-linking of fibrin clots. A papain-based hemostat with increased procoagulant activity is developed through immobilizing papain on the cellulose carrier, which displays short clotting time in both normal and heparinized plasmas. The excellent hemostatic performance of the papain-based hemostat is further confirmed with reduced hemostatic time and limited blood loss in a mouse tail amputation model, rabbit auricular artery injury model and rat liver injury model, in which a natural coagulation system fails to function on account of heparin. This bio-hemostat has great potential to reverse the effect of heparin and stop topical hemorrhage rapidly in surgical procedures.

Risk and Management of Bleeding Complications with Direct Oral Anticoagulants in Patients with Atrial Fibrillation and Venous Thromboembolism: a Narrative Review

Atrial fibrillation (AF) and venous thromboembolism (VTE) are highly prevalent conditions with a significant healthcare burden, and represent the main indications for anticoagulation. Direct oral anticoagulants (DOACs) are the first choice treatment of AF/VTE, and have become the most prescribed class of anticoagulants globally, overtaking vitamin K antagonists (VKAs). Compared to VKAs, DOACs have a similar or better efficacy/safety profile, with reduced risk of intracerebral hemorrhage (ICH), while the risk of major bleeding and other bleeding harms may vary depending on the type of DOAC. We have critically reviewed available evidence from randomized controlled trials and observational studies regarding the risk of bleeding complications of DOACs compared to VKAs in patients with AF and VTE. Special patient populations (e.g., elderly, extreme body weights, chronic kidney disease) have specifically been addressed. Management of bleeding complications and possible resumption of anticoagulation, in particular after ICH and gastrointestinal bleeding, are also discussed. Finally, some suggestions are provided to choose the optimal DOAC to minimize adverse events according to individual patient characteristics and bleeding risk.

PARs in the inflammation-cancer transformation of CRC

Colorectal cancer (CRC) is one of the common malignancies with a global trend of increasing incidence and mortality. There is an urgent need to identify new predictive markers and therapeutic targets for the treatment of CRC. Protease-activated receptors (PARs) are a class of G-protein-coupled receptors, with currently identified subtypes including PAR1, PAR2, PAR3 and PAR4. Increasingly, studies suggest that PARs play an important role in the growth and metastasis of CRC. By targeting multiple signaling pathways may contribute to the pathogenesis of CRC. In this review, we first describe recent studies on the role of PARs in CRC inflammation-cancer transformation, focusing on the important role of PARs in signaling pathways associated with inflammation-cancer transformation, and summarize the progress of research on PARs-targeted drugs.

Coming soon to a pharmacy near you? FXI and FXII inhibitors to prevent or treat thromboembolism

Anticoagulants have been in use for nearly a century for the treatment and prevention of venous and arterial thromboembolic disorders. The most dreaded complication of anticoagulant treatment is the occurrence of bleeding, which may be serious and even life-threatening. All available anticoagulants, which target either multiple coagulation factors or individual components of the tissue factor (TF) factor VIIa or the common pathways, have the potential to affect hemostasis and thus to increase bleeding risk in treated patients. While direct oral anticoagulants introduced an improvement in care for eligible patients in terms of safety, efficacy, and convenience of treatment, there remain unmet clinical needs for patients requiring anticoagulant drugs. Anticoagulant therapy is sometimes avoided for fear of hemorrhagic complications, and other patients are undertreated due to comorbidities and the perception of increased bleeding risk. Evidence suggests that the contact pathway of coagulation has a limited role in initiating physiologic in vivo coagulation and that it contributes to thrombosis more than it does to hemostasis. Because inhibition of the contact pathway is less likely to promote bleeding, it is an attractive target for the development of anticoagulants with improved safety. Preclinical and early clinical data indicate that novel agents that selectively target factor XI or factor XII can reduce venous and arterial thrombosis without an increase in bleeding complications.

Engineering the Cyclization Loop of MCoTI-II Generates Targeted Cyclotides that Potently Inhibit Factor XIIa

Factor XIIa (FXIIa) is a promising target for developing new drugs that prevent thrombosis without causing bleeding complications. A native cyclotide (MCoTI-II) is gaining interest for engineering FXIIa-targeted anticoagulants as this peptide inhibits FXIIa but not other coagulation proteases. Here, we engineered the native biosynthetic cyclization loop of MCoTI-II (loop 6) to generate improved FXIIa inhibitors. Decreasing the loop length led to gains in potency up to 7.7-fold, with the most potent variant having five residues in loop 6 (K_i = 25 nM). We subsequently examined sequence changes within loop 6 and an adjacent loop, with substitutions at P4 and P2' producing a potent FXIIa inhibitor (K_i = 2 nM) that displayed more than 700-fold selectivity, was stable in human serum, and blocked the intrinsic coagulation pathway in human plasma. These findings demonstrate that engineering the biosynthetic cyclization loop can generate improved cyclotide variants, expanding their potential for drug discovery.

Vitamin-K Antagonists vs. Direct Oral Anticoagulants on Severity of Upper Gastrointestinal Bleeding: A Retrospective Analysis of Italian and UK Data

Background: Gastrointestinal bleeding (GIB) is one of most frequent and significant challenges for emergency physicians and gastroenterologists. Mortality for upper (U) GIB is high, especially in the elderly and comorbid patients. However, there is scant evidence in the literature concerning an assessment of warfarin (VKA) and direct oral anticoagulants (DOACs) in terms of upper gastrointestinal bleeding (UGIB) severity. Aims: Using data from two different settings (Italy and the UK), we aimed to compare the impact of VKA and DOACs on the severity of UGIB. Methods: Retrospective bicentric study on adult patients under VKA or DOACs admitted either to the emergency department at the Gemelli Hospital in Rome, Italy or University College Hospital in London, UK, with suspected UGIB from 01/01/2017 to 31/12/2018. Univariate analysis with Fisher’s exact test, and analysis of variance (ANOVA) were used. Results: 106 patients (62 M/44 F; mean age 71.2 ± 16.9 yrs) were enrolled and divided into the VKA group (N = 57; M: 56%, mean age: 64.9 ± 21.3 yrs) and the DOAC group (N = 49; M: 61%; mean age: 77.6 ± 12.5 yrs). At univariate analysis, the VKA group presented two endoscopic diagnoses more frequently than the DOAC group (26% vs. 8%, p < 0.05), were more frequently endoscopically treated (44% vs. 22%, p < 0.05), rescoped (12% vs. 2%, p = 0.048) and hospitalized (79% vs. 53%, p = 0.01) with a longer length of stay, LOS (VKA: 58% > 5 days vs. DOAC: 68% < 5 days, p = 0.01). There was no difference in terms of hemoglobin level on admission, however the requirement of blood transfusions was higher in the VKA group (60% vs. 41%, p = 0.041). One third of the VKA group showed a lower platelet count than the DOAC group (33% vs. 8%, p = 0.01). No statistically significant differences for in-hospital mortality were observed. For the ANOVA, the type of anticoagulant used was the only significant predictor of need to rescope (p = 0.041) and a significant co-predictor for a LOS > 5 days (p = 0.009; as well as cirrhosis, p = 0.013 and age, p = 0.005). Conclusions: Our outcomes revealed a more severe UGIB in patients on VKA, but the impact of comorbidities (i.e., more cirrhotic patients in the VKA group) cannot be disregarded. DOAC subgroup descriptive analysis, even though on a little cohort, showed higher bleeding severity for rivaroxaban.

Platelet-Inspired Intravenous Nanomedicine for Injury-Targeted Direct Delivery of Thrombin to Augment Hemostasis in Coagulopathies

Severe hemorrhage associated with trauma, surgery, and congenital or drug-induced coagulopathies can be life-threatening and requires rapid hemostatic management via topical, intracavitary, or intravenous routes. For injuries that are not easily accessible externally, intravenous hemostatic approaches are needed. The clinical gold standard for this is transfusion of blood products, but due to donor dependence, specialized storage requirements, high risk of contamination, and short shelf life, blood product use faces significant challenges. Consequently, recent research efforts are being focused on designing biosynthetic intravenous hemostats, using intravenous nanoparticles and polymer systems. Here we report on the design and evaluation of thrombin-loaded injury-site-targeted lipid nanoparticles (t-TLNPs) that can specifically localize at an injury site via platelet-mimetic anchorage to the von Willebrand factor (vWF) and collagen and directly release thrombin via diffusion and phospholipase-triggered particle destabilization, which can locally augment fibrin generation from fibrinogen for hemostatic action. We evaluated t-TLNPs in vitro in human blood and plasma, where hemostatic defects were created by platelet depletion and anticoagulation. Spectrophotometric studies of fibrin generation, rotational thromboelastometry (ROTEM)-based studies of clot viscoelasticity, and BioFlux-based real-time imaging of fibrin generation under simulated vascular flow conditions confirmed that t-TLNPs can restore fibrin in hemostatic dysfunction settings. Finally, the in vivo feasibility of t-TLNPs was tested by prophylactic administration in a tail-clip model and emergency administration in a liver-laceration model in mice with induced hemostatic defects. Treatment with t-TLNPs was able to significantly reduce bleeding in both models. Our studies demonstrate an intravenous nanomedicine approach for injury-site-targeted direct delivery of thrombin to augment hemostasis.

Efficacy of traditional Chinese medicine combined with rivaroxaban in the treatment of lower extremity deep vein thrombosis: A meta-analysis

BACKGROUND

Despite the usefulness of traditional Chinese medicine (TCM) in the treatment of lower deep vein thrombosis (DVT), there is no consensus on safety and efficacy. We aim to systematically evaluate the safety and efficacy of TCM combined with Rivaroxaban in the treatment of lower limb DVT.

METHODS

An online search of databases such as Cochrane Library, Embase, Pubmed, and Web of science, as well as CBM, China Science and Technology Journal Database, China Knowledge Network (CNKI) and Wanfang Data (from inception to July, 2021) was performed. All published clinical randomized controlled trials (RCTs) were screened manually, evaluated for quality and considered for meta-analysis using RevMan 5.3.

RESULTS

Nine RCTs with a total of 730 cases were included, 368 cases in the trial group were treated with TCM combined with Rivaroxaban, and 362 cases in the control group were treated with Rivaroxaban alone after surgery. Clinical efficiency was significantly higher in the test group [OR = 3.33, 95% CI (2.01, 5.53), P < .00001], the circumference of the affected limb was significantly lower in the thigh and calf, respectively [MD = -1.48, 95% CI (-1.88, -1.09), P < .00001], [MD = -0.54, 95% CI (-0.62, -0.46), P < .00001], pain scores were significantly lower [MD = -0.97, 95% CI (-1.58, -0.36), P = .002], coagulation index plasma fibrinogen (FIB) was significantly lower [MD = -0.85, 95% CI (-1.18, -0.52), P < .00001], coagulation function index D-2 aggregates were significantly reduced [MD = -0.69, 95% CI (-1.13, -0.24), P = .002], serum hypersensitive C-reactive protein (hs-CRP) measurements were significantly reduced [MD = -5.37, 95% CI (-9.20, -1.55), P = .006], complications measurement was significantly lower [OR = 0.60, 95% CI (0.27, 1.30), P = .20], activated partial thrombin time (ATPP) measurement was significantly lower [MD = 5.70, 95% CI (4.28, 7.12), P < .00001] and prothrombin time (PT) measurement was significantly lower [MD = 1.64, 95% CI (0.70, 2.57), P = .0006].

CONCLUSION

Based on the available evidence, TCM combined with Rivaroxaban for treating lower extremity DVT have better clinical efficacy and safety profile, reducing the risk of bleeding complications and adverse effects. Further improved studies are needed to support this inference.

Incidence, risk factors, and clinical impact of major bleeding in hospitalized patients with COVID-19: a sub-analysis of the CLOT-COVID Study

Background

The coronavirus disease 2019 (COVID-19) causes extensive coagulopathy and a potential benefit of anticoagulation therapy has been documented for prevention of thromboembolic events. Bleeding events has also been reported as a notable complication; whereas, the incidence, risks, and clinical impact of bleeding remain unclear.

Method

The CLOT-COVID Study was a nationwide, retrospective, multicenter cohort study on consecutive hospitalized patients with COVID-19 in Japan between April 2021 and September 2021. In this sub-analysis, we compared the characteristics of patients with and without major bleeding; moreover, we examined the risk factors for and clinical impact of bleeding events.

Results

Among 2882 patients with COVID-19, 57 (2.0%) had major bleeding. The incidence of major bleeding increased with COVID-19 severity as follows: 0.5%, 2.3%, and 12.3% in patients with mild, moderate, and severe COVID-19, respectively. COVID-19 severity, history of major bleeding, and anticoagulant type/dose were independently and additively associated with the bleeding incidence. Compared with patients without major bleeding, those with major bleeding exhibited a longer duration of hospitalization (9 [6–14] vs 28 [19–43] days, P < 0.001) and higher mortality during hospitalization (4.9% vs. 35.1%, P < 0.001).

Conclusions

In the real-world clinical practice, the incidence of major bleeding was not uncommon, especially in patients with severe COVID-19. Independent risk factors for major bleeding included history of major bleeding, COVID-19 severity, and anticoagulant use, which could be associated with poor clinical outcomes including higher mortality. Precise recognition of the risks for bleeding may be helpful for an optimal use of anticoagulants and for better outcomes in patients with COVID-19.

A Historical Perspective on the Reversal of Anticoagulants

There has been a landmark shift in the last several decades in the management and prevention of thromboembolic events. From the discovery of parenteral and oral agents requiring frequent monitoring as early as 1914, to the development of direct oral anticoagulants (DOACs) that do not require monitoring or dose adjustment in the late 20th century, great advances have been achieved. Despite the advent of these newer agents, bleeding continues to be a key complication, affecting 2 to 4% of DOAC-treated patients per year. Bleeding is associated with substantial morbidity and mortality. Although specific reversal agents for DOACs have lagged the release of these agents, idarucizumab and andexanet alfa are now available as antagonists. However, the efficacy of these reversal agents is uncertain, and complications, including thrombosis, have not been adequately explored. As such, guidelines continue to advise the use of nonspecific prohemostatic agents for patients requiring reversal of the anticoagulant effect of these drugs. As the indications for DOACs and the overall prevalence of their use expand, there is an unmet need for further studies to determine the efficacy of specific compared with nonspecific pro-hemostatic reversal agents. In this review, we will discuss the evidence behind specific and nonspecific reversal agents for both parenteral and oral anticoagulants.

Challenging clinical scenarios for therapeutic anticoagulation: A practical approach

Therapeutic anticoagulation remains a fundamental backbone in the treatment and prevention of venous thromboembolism. However, while modern therapies are increasingly safe, anticoagulation is not without risks, particularly in those at high risk for or with recent bleeding. When weighing concurrent risks and benefits in each challenging clinical scenario, an individualized assessment of the risk and acuity of bleeding should be balanced by the indication for anticoagulation. Addressing modifiable risk factors and routine re-evaluation of any changes in this balance is critical. This review outlines available data and current guidelines for the management of anticoagulation in high-risk populations, including those with thrombocytopenia, elderly and high-fall risk, inherited bleeding disorders, and in acute coronary syndrome. We also examine management after clinically significant bleeding episodes, including intracranial hemorrhage, gastrointestinal bleeding, hemoptysis, retroperitoneal bleeding, hematuria, and abnormal uterine bleeding. The aim is to provide a comprehensive review of available literature to guide clinicians in providing optimal, safe, and individualized care for patients in these challenging scenarios.

Purification, structural characterization, and anticoagulant activity evaluation of chondroitin sulfate from codfish (Gadus macrocephalus) bones

Chondroitin sulfate (CCS) was purified from discarded codfish (Gadus macrocephalus) bones, and its chemical structure and anticoagulant activity were assessed. CCS was obtained via enzymatic lysis and ion-exchange column chromatography, with a yield of approximately 0.15%. High-performance gel performance chromatography revealed CCS to be a largely homogeneous polysaccharide with a relatively low molecular weight of 12.3 kDa. FT-IR spectroscopy, NMR spectroscopy, and SAX-HPLC indicated that CCS was composed of monosulfated disaccharides (ΔDi4S 73.85% and ΔDi6S 19.06%) and nonsulfated disaccharides (ΔDi0S 7.09%). In vitro anticoagulation analyses revealed that CCS was able to significantly prolong activated partial thromboplastin time (APTT) and thrombin time (TT) (p < 0.05). At a CCS concentration of 5 μg/mL and 25 μg/mL, APTT and TT were approximately 1.08 and 1.12 times higher, respectively, compared to the negative control group. The results indicated that CCS might offer value as a dietary fiber supplement with the potential to prevent the incidence of coagulation-related thrombosis.

The interaction between anti-PF4 antibodies and anticoagulants in vaccine-induced thrombotic thrombocytopenia

Life-threatening thrombotic events at unusual sites have been reported after vector-based vaccinations against severe acute respiratory syndrome coronavirus 2. This phenomenon is now termed vaccine-induced immune thrombotic thrombocytopenia (VITT). The pathophysiology of VITT is similar to that of heparin-induced thrombocytopenia (HIT) and is associated with platelet-activating antibodies (Abs) against platelet factor 4 (PF4). Therefore, current guidelines suggest nonheparin anticoagulants to treat VITT patients. In this study, we investigated the interactions of heparin, danaparoid, fondaparinux, and argatroban with VITT-Ab/PF4 complexes using an ex vivo model for thrombus formation as well as in vitro assays to analyze Ab binding and platelet activation. We found that immunoglobulin Gs (IgGs) from VITT patients induce increased adherent platelets/thrombus formation in comparison with IgGs from healthy controls. In this ex vivo flow-based model, the procoagulant activity of VITT IgGs was effectively inhibited with danaparoid and argatroban but also by heparin. Interestingly, heparin and danaparoid not only inhibited IgG binding to PF4 but were also able to effectively dissociate the preformed PF4/IgG complexes. Fondaparinux reduced the in vitro generation of procoagulant platelets and thrombus formation; however, it did not affect platelet aggregation. In contrast, argatroban showed no effect on procoagulant platelets and aggregation but significantly inhibited VITT-mediated thrombus formation. Taken together, our data indicate that negatively charged anticoagulants can disrupt VITT-Ab/PF4 interactions, which might serve as an approach to reduce Ab-mediated complications in VITT. Our results should be confirmed, however, in a clinical setting before a recommendation regarding the selection of anticoagulants in VITT patients could be made.

Pharmacokinetic, Hemostatic, and Anticancer Properties of a Low-Anticoagulant Bovine Heparin

Heparin is a centennial anticoagulant drug broadly employed for treatment and prophylaxis of thromboembolic conditions. Although unfractionated heparin (UFH) has already been shown to have remarkable pharmacological potential for treating a variety of diseases unrelated with thromboembolism, including cancer, atherosclerosis, inflammation, and virus infections, its high anticoagulant potency makes the doses necessary to exert non-hemostatic effects unsafe due to an elevated bleeding risk. Our group recently developed a new low-anticoagulant bovine heparin (LABH) bearing the same disaccharide building blocks of the UFH gold standard sourced from porcine mucosa (HPI) but with anticoagulant potency approximately 85% lower (approximately 25 and 180 Heparin International Units [IU]/mg). In the present work, we investigated the pharmacokinetics profile, bleeding potential, and anticancer properties of LABH administered subcutaneous into mice. LABH showed pharmacokinetics profile similar to HPI but different from the low-molecular weight heparin (LMWH) enoxaparin and diminished bleeding potential, even at high doses. Subcutaneous treatment with LABH delays the early progression of Lewis lung carcinoma, improves survival, and brings beneficial health outcomes to the mice, without the advent of adverse effects (hemorrhage/mortality) seen in the animals treated with HPI. These results demonstrate that LABH is a promising candidate for prospecting new therapeutic uses for UFH.

Growth Differentiation Factor-15 Based ABC (Age, Biomarkers, Clinical History)-AF (Atrial Fibrillation)-Bleeding Risk Score for Elderly Patients with Nonvalvular Atrial Fibrillation

Background

Growth differentiation factor-15 (GDF-15) is a strong predictor of bleeding in atrial fibrillation (AF) patients. The novel ABC (age, biomarkers, and clinical history), AF, and bleeding risk score outperforms HAS-BLED bleeding risk score for major bleeding (MB) in patients with AF receiving oral anti-coagulation in the clinical trial cohort. However, it has not been entirely externally validated. We aimed to refine and understand the application of the ABC-AF bleeding risk score in elderly (aged ≥65 years old) patients with nonvalvular atrial fibrillation (NVAF) for predicting the different types of bleeding events and anti-thrombotic treatments.

Methods

We identified elderly patients with NVAF between March 2018 and December 2019 who were hospitalized for the first time after a diagnosis of NVAF. We measured the plasma concentration of the ABC biomarkers (growth differentiation factor 15 (GDF-15) and cardiac troponin-T (cTnT)) from enrolled patients. We collected their general information and follow up for one year until December 2020. During the follow-up period, information on the occurrence of bleeding events (major bleeding, clinically relevant nonmajor gastrointestinal bleeding (CRNM GIB), and minor bleeding events) was collected.

Results

We enrolled 342 elderly NAVF patients; the ABC-AF bleeding and HAS-BLED scores were quantified. With an average of 1.5 years of follow-up, 6 patients had an intracranial hemorrhage; 57 patients had CRNM GIB; and 68 patients had minor bleeding events (36 fecal occult blood positive and 32 other minor bleeding events). The ABC-AF bleeding score yielded a C-index of 0.72 (95% CI 0.60–0.84) for predicting MB in elderly patients with NAVF, C-index of 0.69 (95% CI 0.57–0.82) by HAS-BLED score. Comparison of the incidence of bleeding events during follow-up and the predicted 1-year incidence of bleeding events by each bleeding risk score, ABC-AF bleeding, and HAS-BLED scores have similar value in predicting the risk for elderly patients with NAVF in different types of bleeding events, whether on oral anti-coagulation treatment (OAC) or non-OAC (P > 0.05).

Conclusion

In elderly patients with NVAF, the biomarker-based ABC-AF bleeding score showed similar performance compared with the HAS-BLED bleeding risk score.

Design and fabrication of r-hirudin loaded dissolving microneedle patch for minimally invasive and long-term treatment of thromboembolic disease

Cardiovascular disease is the leading cause of global mortality, with anticoagulant therapy being the main prevention and treatment strategy. Recombinant hirudin (r-hirudin) is a direct thrombin inhibitor that can potentially prevent thrombosis via subcutaneous (SC) and intravenous (IV) administration, but there is a risk of haemorrhage via SC and IV. Thus, microneedle (MN) provides painless and sanitary alternatives to syringes and oral administration. However, the current technological process for the micro mould is complicated and expensive. The micro mould obtained via three-dimensional (3D) printing is expected to save time and cost, as well as provide a diverse range of MNs. Therefore, we explored a method for MNs array model production based on 3D printing and translate it to micro mould that can be used for fabrication of dissolving MNs patch. The results show that r-hirudin-loaded and hyaluronic acid (HA)-based MNs can achieve transdermal drug delivery and exhibit significant potential in the prevention of thromboembolic disease without bleeding in animal models. These results indicate that based on 3D printing technology, MNs combined with r-hirudin are expected to achieve diverse customizable MNs and thus realize personalized transdermal anticoagulant delivery for minimally invasive and long-term treatment of thrombotic disease.

Percutaneous Thrombectomy for the Treatment of Lower Extremity Deep Vein Thrombosis: Medium-Term Follow-up Results and Analysis of 112 Cases

Introduction

The aim of this study was to analyze percutaneous thrombectomy (PT) outcomes for the management of lower extremity deep vein thrombosis (DVT) with medium-term follow-up.

Methods

The study included charts of patients who underwent PT due to lower extremity DVT between August 2017 and March 2021. Patient characteristics and procedure outcomes were recorded in the electronic information system on the same day as the procedure. The procedures with complete removal of thrombus following PT without requiring additional procedure or additional thrombectomy apparatus were considered successful. Also, duration of follow-up was noted.

Results

In total, 112 patients were enrolled in the study. The femoropopliteal (40.2%) and iliofemoral (25.0%) veins were the most common sites with thrombus detected. The duration of PT procedure and fluoroscopy were 123.1 minutes and 21.9 minutes, respectively. Estimated blood loss was 255.1 milliliters. The hospital stay and intensive care unit stay following PT were 3.7 and 1.4 days, respectively. Major hemorrhage did not occur in any patient, but we encountered bradycardia in six (5.4%) patients, acute renal failure in one (0.9%) patient, hemoglobinuria in 11 (9.8%) patients, leg pain in 15 (13.4%) patients, and pulmonary embolism in 2 (1.8) patients, respectively. Success of the present study was 94.6% in the first month, and re-operation was required only in one patient. The mean follow-up period was 21.1 months with 90.2% venous patency rates.

Conclusion

The present study demonstrated that PT was an effective and reliable treatment modality with acceptable complication rates for the treatment of lower extremity DVT. Additionally, the efficacy of PT was proven by mid-term follow-up results.

Pharmacokinetic, hemostatic and anticancer properties of a low-anticoagulant bovine heparin

Heparin is a centennial anticoagulant drug broadly employed for treatment and prophylaxis of thromboembolic conditions. Although unfractionated heparin (UFH) has already been shown to have remarkable pharmacological potential for treating a variety of diseases unrelated with thromboembolism, including cancer, atherosclerosis, inflammation, and virus infections, its high anticoagulant potency makes the doses necessary to exert non-hemostatic effects unsafe due to an elevated bleeding risk. Our group recently developed a new low-anticoagulant bovine heparin (LABH) bearing the same disaccharide building blocks of the UFH gold standard sourced from porcine mucosa (HPI) but with anticoagulant potency approximately 85% lower (approximately 25 and 180 Heparin International Units [IU]/mg). In the present work, we investigated the pharmacokinetics profile, bleeding potential, and anticancer properties of LABH administered subcutaneous into mice. LABH showed pharmacokinetics profile similar to HPI but different from the low-molecular weight heparin (LMWH) enoxaparin and diminished bleeding potential, even at high doses. Subcutaneous treatment with LABH delays the early progression of Lewis lung carcinoma, improves survival, and brings beneficial health outcomes to the mice, without the advent of adverse effects (hemorrhage/mortality) seen in the animals treated with HPI. These results demonstrate that LABH is a promising candidate for prospecting new therapeutic uses for UFH.

Bivalirudin Presents a Favorable Safety Profile Regarding Adverse Drug Reactions, Thrombocytopenia, and Bleeding in Chinese Patients With High Bleeding Risk Undergoing Percutaneous Coronary Intervention: A Prospective, Multi-Center, Intensive Monitoring Study

Background

This study aimed to comprehensively explore the occurrence and risk factors for adverse events (AEs) and adverse drug reactions (ADRs) (especially for thrombocytopenia and bleeding) in Chinese patients with high bleeding risk (older adults, or complicated with diabetes mellitus or renal function impairment) undergoing percutaneous coronary intervention (PCI) with bivalirudin as an anticoagulant.

Methods

A total of 1,226 patients with high bleeding risk who received PCI with bivalirudin as an anticoagulant from 27 Chinese medical centers were enrolled in this prospective, multi-center, intensive monitoring study. AEs, ADRs, thrombocytopenia, and bleeding were collected from admission to 72 h post-bivalirudin administration; subsequently, patients were followed up on the 30th day with the safety data collected as well.

Results

Adverse events were observed in 198 (16.2) patients, among which severe AEs occurred in 16 (1.3%) patients. Meanwhile, bivalirudin-related ADRs were reported in 66 (5.4%) patients, among which 5 (0.4%) patients experienced bivalirudin-related severe ADRs. Besides, thrombocytopenia and bleeding occurred in 45 (3.7%) and 19 (1.5%) patients, respectively. The subsequent multivariate logistic analysis revealed that age >75 years [p = 0.017, odds ratio (OR) = 1.856] and spontaneous coronary artery dissection (SCAD) (p = 0.030, OR = 2.022) were independently related to higher ADR risk; SCAD (p = 0.017, OR = 2.426) was independently correlated with higher thrombocytopenia risk, while radial artery access (p = 0.015, OR = 0.352) was independently correlated with lower thrombocytopenia risk; and the administration of bivalirudin preoperatively or intraoperatively (p = 0.013, OR = 5.097) was independently associated with higher bleeding risk.

Conclusion

Bivalirudin presents a favorable safety profile regarding ADRs, thrombocytopenia, and bleeding in Chinese patients with high bleeding risk undergoing PCI.

Learning curve for percutaneous thrombectomy in treatment of acute lower extremity deep vein thrombosis

OBJECTIVE

We evaluated the effect of the learning curve on percutaneous thrombectomy (PT) outcomes for the treatment of lower extremity deep vein thrombosis (DVT).

METHODS

The present study was conducted between October 2019 and September 2020 and included 80 patients who had undergone PT to treat lower extremity DVT of the common iliac, external iliac, common femoral, femoral, and popliteal veins. For thrombectomy, aspiration and mechanical thrombectomy procedures were performed until the thrombus had completely dissolved using the Dovi aspiration system and Mantis mechanical thrombectomy system (Invamed, Ankara, Turkey). A total of 80 patients were divided equally into four groups, with the first 20 cases in group 1, the second 20 cases in group 2, the third 20 cases in group 3, and the final 20 cases in group 4. The groups were compared for the demographic characteristics, intraoperative outcomes, complication rates, and procedure success.

RESULTS

All demographic parameters were similar between the four groups. The mean operative time was 139.3 minutes for group 1, 134.8 minutes for group 2, 111.3 minutes for group 3, and 106.7 minutes for group 4. Statistical analysis revealed that the operative time was significantly shorter for groups 3 and 4 compared with that for groups 1 and 2. In addition, the fluoroscopy time was significantly decreased in groups 3 and 4 (P = .001). The complication rate was similar between the four groups (P = .899). However, success was significantly increased after the first 20 cases, and the remaining three groups had a significantly higher success rate compared with group 1 (70% for group 1, 90% for group 2, 95% for group 3, and 100% for group 4; P = .024).

CONCLUSIONS

Success in the performance of PT for the treatment of acute lower extremity DVT reaches satisfactory levels after 20 cases. Additionally, operation time and fluoroscopy time are significantly decreased after 40 cases and then start plateau.

Endothelial contribution to COVID-19: an update on mechanisms and therapeutic implications

The global propagation of SARS-CoV-2 leads to an unprecedented public health emergency. Despite that the lungs are the primary organ targeted by COVID-19, systemic endothelial inflammation and dysfunction is observed particularly in patients with severe COVID-19, manifested by elevated endothelial injury markers, endotheliitis, and coagulopathy. Here, we review the clinical characteristics of COVID-19 associated endothelial dysfunction; and the likely pathological mechanisms underlying the disease including direct cell entry or indirect immune overreactions after SARS-CoV-2 infection. In addition, we discuss potential biomarkers that might indicate the disease severity, particularly related to the abnormal development of thrombosis that is a fatal vascular complication of severe COVID-19. Furthermore, we summarize clinical trials targeting the direct and indirect pathological pathways after SARS-CoV-2 infection to prevent or inhibit the virus induced endothelial disorders.

Managing patients on direct factor Xa inhibitors with rapid thrombelastography

The use of direct factor Xa inhibitors rivaroxaban and apixaban (XABANs) has rapidly increased; however, there is no validated test available to monitor the effect on hemostasis. This study aims to assess how hemostatic management based on the Rapid Thromboelastography (R-TEG) variable activated clotting time (ACT) of XABAN patients with ongoing bleedings or in need for acute surgical intervention, affected patient outcome. A total of 343 XABAN patients were included in the main analysis together with 50 healthy volunteers to validate the reference value for ACT. An ACT >120 s (s) was defined as having XABAN-induced coagulopathy. Sixty-five percent of the XABAN patients presented with R-TEG ACT within the normal reference. Patients with XABAN-induced coagulopathy had a significantly increased risk of severe bleeding. Significantly more patients with extra-cerebral bleeding (ECB) and ACT above 120 s were transfused with five red blood cell (RBC) units or more compared to patients with ACT at 120 s or below (17% vs. 3%, p <.05). Significantly more XABAN-patients with ACT above 120 s received pro-hemostatic intervention with prothrombin complex concentrate (PCC) when compared to those with ACT at 120 s or below (ECB: 2% vs. 8%, p =.03, intracranial hemorrhage: 25% vs. 68%, p <.00). Patients who received PCC had a higher 30- and 90-day mortality compared to the rest of the cohort (16% vs. 6%, p = .02 and 21% vs. 7%, p =.00). Patients with XABAN-induced coagulopathy as evaluated by R-TEG ACT presented with more severe bleeding and higher transfusion requirements when compared to those with ACT in the normal range. This suggests that R-TEG ACT measurement in XABAN patients with active hemorrhage or in need for acute surgery may be of clinical value.

Incidence, risk factors, and management of bleeding in patients receiving anticoagulants for the treatment of cancer-associated thrombosis

Updated clinical practice guidelines recommend the long-term use of low-molecular-weight heparins or direct oral anticoagulants as the preferred option for the treatment of cancer-associated thrombosis (CAT), using a personalized approach matching the right drug to the right patient. In most cases, the benefit of anticoagulant therapy outweighs the risk. However, the long-term use of anticoagulants is associated with a non-negligible risk of bleeding, which constitutes a rare but serious adverse effect. Bleeding complications have been reported to be overall 2 to 3 times more frequent in cancer patients with CAT receiving anticoagulation than in non-cancer patients, with a reported incidence of major bleeding ranging from 2.4 to 16.0% in randomized controlled trials (RCT). In the absence of validated risk assessment model to predict the risk of bleeding in these patients, a careful evaluation of each individual profile, with adequate selection of the most appropriate anticoagulant for each individual patient, is warranted for overcoming management challenges, taking in account the numerous factors which may potentiate the overall bleeding risk in these complex patients, such as advanced or metastatic disease, older age, anemia, thrombocytopenia, renal impairment, liver dysfunction, and concomitant anticancer therapies. The purpose of this review is to call for awareness on bleeding complications as a major safety issue of CAT treatment and to summarize data from recent RCT and real-world studies on the incidence and risk factors for bleeding in this unique and challenging population to further help clinicians in decision-making.

Recurrent bleeding and thrombotic events after resumption of oral anticoagulants following gastrointestinal bleeding: Communication from the ISTH SSC Subcommittee on Control of Anticoagulation

BACKGROUND

Gastrointestinal bleeding frequently complicates anticoagulant therapy causing treatment discontinuation. Data to guide the decision regarding whether and when to resume anticoagulation based on the risks of thromboembolism and recurrent bleeding are scarce.

OBJECTIVES

We aimed to retrospectively evaluate the incidence of these events after anticoagulant-related gastrointestinal bleeding and assess their relationship with timing of anticoagulation resumption.

METHODS

Patients hospitalized because of gastrointestinal bleeding during oral anticoagulation for any indication were eligible. All patients were followed up to 2 years after the index bleeding for recurrent major or clinically relevant non-major bleeding, venous or arterial thromboembolism, and mortality.

RESULTS

We included 948 patients hospitalized for gastrointestinal bleeding occurring during treatment with vitamin K antagonists (n = 531) or direct oral anticoagulants (n = 417). In time-dependent analysis, anticoagulant treatment was associated with a higher risk of recurrent clinically relevant bleeding (hazard ratio [HR] 1.55; 95% confidence interval [CI] 1.08-2.22), but lower risk of thromboembolism (HR 0.34; 95% CI 0.21-0.55), and death (HR 0.50; 95% CI 0.36-0.68). Previous bleeding, index major bleeding, and lower glomerular filtration rate were associated with a higher risk of recurrent bleeding. The incidence of recurrent bleeding increased after anticoagulation restart independently of timing of resumption.

CONCLUSIONS

Anticoagulant treatment after gastrointestinal bleeding is associated with a lower risk of thromboembolism and death, but higher risk of recurrent bleeding. The latter seemed to be influenced by patient characteristics and less impacted by time of anticoagulation resumption.

Antithrombotic and Antiplatelet Drug Toxicity

Anticoagulant and antiplatelet drugs target a specific portion of the coagulation cascade or the platelet activation and aggregation pathway. The primary toxicity associated with these agents is hemorrhage. Understanding the pharmacology of these drugs allows the treating clinician to choose the correct antidotal therapy. Reversal agents exist for some of these drugs; however, not all have proven patient-centered outcomes. The anticoagulants covered in this review are vitamin K antagonists, heparins, fondaparinux, hirudin derivatives, argatroban, oral factor Xa antagonists, and dabigatran. The antiplatelet agents reviewed are aspirin, adenosine diphosphate antagonists, dipyridamole, and glycoprotein IIb/IIIa antagonists. Additional notable toxicities are also reviewed.

Genetic Risk Profiling Associated with Recurrent Unprovoked Venous Thromboembolism

INTRODUCTION

Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and/or pulmonary embolism (PE), is a common, acute, multifactorial disease with a five-years cumulative incidence of recurrence of approximately 25%. Actually, no single genetic defect can predict the risk of recurrence of VTE. Therefore, individual genetic risk profiling could be useful for the prediction of VTE recurrence.

AIM OF THE STUDY

To assess the combined effect of the common prothrombotic genotypes on the risk of recurrence of VTE in recently diagnosed unprovoked VTE patients.

PATIENTS AND METHODS

This population based, prospective follow-up study was carried out from January 2015 to December 2020 in (internal medicine, cardiovascular medicine and anesthesia and ICU departments, Tanta University Hospital, Egypt) on 224 recently diagnosed unprovoked VTE patients. Whole blood was collected by standard venipuncture at the time of admission prior to the beginning of anticoagulant therapy. Genomic DNA was extracted and was genotyped for the 5-SNPs Genetic risk score (GRS), previously validated for first venous thrombosis (FVL rs6025, PTM rs1799963, ABO rs8176719, FGG rs2066865 and FXI rs2036914).

RESULTS

The main important finding in the present study was that patients having ≥3 risk alleles were associated with higher risk of VTE recurrence compared to those having ≤2 risk alleles (the reference group) (HR 2.5, 95% CI 1.48-4.21) (p = 0.001). Patients with GRS ≥ 3 had a significantly shorter time recurrence free survival (43.07 months) compared to the low risk group of patients with GRS (0-2) (p < 0.001).

CONCLUSION

GRS model could be an effective and useful model in risk stratification of VTE patients, and genetic risk profiling of VTE patients could be used for the prediction of recurrence of VTE.

Adverse event rates associated with oral anticoagulant treatment early versus later after hospital discharge in older adults: a retrospective population-based cohort study

BACKGROUND

Oral anticoagulants are commonly used high-risk medications, but little is known about their safety in transition from hospital to home. Our objective was to measure the rates of hemorrhage and thromboembolic events among older adults receiving oral anticoagulant treatment early after hospital discharge compared to later.

METHODS

We conducted a retrospective population-based cohort study among Ontario residents aged 66 years or more who started, continued or resumed oral anticoagulant therapy at hospital discharge between September 2010 and March 2015. We calculated the rates of hemorrhage and thromboembolic events requiring hospital admission or an emergency department visit over a 1-year follow-up period, stratified by the first 30 days after discharge and the remainder of the year. We used multivariable regression models, adjusting for covariates, to estimate the effect of sex, prevalent versus incident use, and switching anticoagulants on events.

RESULTS

A total of 123 139 patients (68 408 women [55.6%]; mean age 78.2 yr) were included. About one-quarter (32 563 [26.4%]) had a Charlson Comorbidity Index score of 2 or higher. The rates of hemorrhage and thromboembolic events per 100 person-years were highest during the first 30 days after hospital discharge (25.8, 95% CI 24.8-26.8 and 19.3, 95% CI 18.4-20.2, respectively), falling to 15.7 (95% CI 15.3-16.1) and 6.9 (95% CI 6.6-7.1), respectively, during the subsequent 11 months. Multivariable analysis showed that patients whose anticoagulant was switched in hospital and men had more hemorrhages and thromboembolic events in follow-up.

INTERPRETATION

The first few weeks following hospital discharge represent a very high-risk period for adverse events related to oral anticoagulant treatment among older adults. The results support an intervention trial addressing anticoagulation management in the early postdischarge period.

Mortality, critical illness, and mechanical ventilation among hospitalized patients with COVID-19 on therapeutic anticoagulants

Background

COVID-19 is associated with hypercoagulability and increased incidence of thrombosis. We compared the clinical outcomes of adults hospitalized with COVID-19 who were on therapeutic anticoagulants to those on prophylactic anticoagulation.

Materials and methods

We performed an observational study of adult inpatients' with COVID-19 from March 9 to June 26, 2020. We compared patients who were continued on their outpatient prescribed therapeutic anticoagulation and those who were newly started on therapeutic anticoagulation for COVID-19 (without other indication) to those who were on prophylactic doses. The primary outcome was overall death while secondary outcomes were critical illness (World Health Organization Ordinal Scale for Clinical Improvement score ≥5), mechanical ventilation, and death among patients who first had critical illness. We adjusted for age, sex, race, body mass index (BMI), Charlson score, glucose on admission, and use of antiplatelet agents.

Results

Of 1716 inpatients with COVID-19, 171 patients were continued on their therapeutic anticoagulation and 78 were started on new therapeutic anticoagulation for COVID-19. In patients continued on home therapeutic anticoagulation, there were no differences in overall death, critical illness, mechanical ventilation, or death among patients with critical illness compared to patients on prophylactic anticoagulation. In patients receiving new therapeutic anticoagulation for COVID-19, there was increased death (OR 5.93; 95% CI 3.71-9.47), critical illness (OR 14.51; 95% CI 7.43-28.31), need mechanical ventilation (OR 11.22; 95% CI 6.67-18.86), and death after first having critical illness (OR 5.51; 95% CI 2.80-10.87).

Conclusions

Therapeutic anticoagulation for inpatients with COVID-19 was not associated with improved outcomes.

Discovery of exolytic heparinases and their catalytic mechanism and potential application

Heparinases (Hepases) are critical tools for the studies of highly heterogeneous heparin (HP)/heparan sulfate (HS). However, exolytic heparinases urgently needed for the sequencing of HP/HS chains remain undiscovered. Herein, a type of exolytic heparinases (exoHepases) is identified from the genomes of different bacteria. These exoHepases share almost no homology with known Hepases and prefer to digest HP rather than HS chains by sequentially releasing unsaturated disaccharides from their reducing ends. The structural study of an exoHepase (BIexoHep) shows that an N-terminal conserved DUF4962 superfamily domain is essential to the enzyme activities of these exoHepases, which is involved in the formation of a unique L-shaped catalytic cavity controlling the sequential digestion of substrates through electrostatic interactions. Further, several HP octasaccharides have been preliminarily sequenced by using BIexoHep. Overall, this study fills the research gap of exoHepases and provides urgently needed tools for the structural and functional studies of HP/HS chains.

Impact of SMTP Targeting Plasminogen and Soluble Epoxide Hydrolase on Thrombolysis, Inflammation, and Ischemic Stroke

Stachybotrys microspora triprenyl phenol (SMTP) is a large family of small molecules derived from the fungus S. microspora. SMTP acts as a zymogen modulator (specifically, plasminogen modulator) that alters plasminogen conformation to enhance its binding to fibrin and subsequent fibrinolysis. Certain SMTP congeners exert anti-inflammatory effects by targeting soluble epoxide hydrolase. SMTP congeners with both plasminogen modulation activity and anti-inflammatory activity ameliorate various aspects of ischemic stroke in rodents and primates. A remarkable feature of SMTP efficacy is the suppression of hemorrhagic transformation, which is exacerbated by conventional thrombolytic treatments. No drug with such properties has been developed yet, and SMTP would be the first to promote thrombolysis but suppress disease-associated bleeding. On the basis of these findings, one SMTP congener is under clinical study and development. This review summarizes the discovery, mechanism of action, pharmacological activities, and development of SMTP.

Definition of major bleeding: Prognostic classification

BACKGROUND

In patients on anticoagulant treatment, the major bleeding (MB) definition released by the International Society of Thrombosis and Haemostasis (ISTH) is widely accepted. However, this definition identifies MBs with highly variable short-term risk of death.

OBJECTIVES

The study aims were to derive and validate a classification of ISTH-defined MBs for the risk of short-term death.

METHODS

Consecutive patients admitted for ISTH-defined MB occurring while on treatment with oral anticoagulants were included in the study and divided into a derivation and a validation cohort. Death within 30 days was the primary study outcome.

RESULTS

Among 1077 patients with MB, 64/517 and 63/560 patients in the derivation and validation cohort died, respectively. In the derivation cohort, Glasgow coma scale (GCS) <14 and shock were predictors of death; critical site bleeding and hemoglobin decrease ≥2 g/dL, or transfusion ≥ 2 units were not. GCS <14 (hazard ratio [HR], 8.67; 95% confidence interval [CI], 3.93-19.13) was predictor of death in intracranial hemorrhage (ICH) and shock at admission (HR, 4.84; 95% CI, 2.01-11.70) and pericardial bleeding (HR, 11.37; 95% CI, 1.33-97.31) in non-ICH MBs. The predictive value of GCS <14 in ICH and shock and pericardial bleeding in non-ICH MBs was confirmed in the validation cohort. None of the patients with isolated ocular or articular bleeding died. A prognostic classification of ISTH-defined MBs for the risk of short-term death is proposed as "serious," "severe," and "life-threatening" (ICH with GCS <14 or non-ICH with shock) MBs.

CONCLUSION

According to our study, ISTH-defined MBs can be stratified for the risk of death within 30 days.