Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

Challenges of Anticoagulation Management Service and Need of Establishing Pharmacist-Led Anticoagulation Clinic in Tertiary Care Teaching Hospital, Ethiopia: A Qualitative Study

Pupose

To explore the challenges of anticoagulation management (AMS) and assess the need for establishing a pharmacist-led anticoagulation clinic (PLAC) at Tikur Anbessa Specialized Hospital (TASH) in Addis Ababa, Ethiopia.

Methods

We conducted a qualitative study at TASH. Using a semistructured interview guide, we interviewed 15 physicians from different specialties, heads of pharmacy and laboratory departments. We also included 20 patients to explore their general perceptions, and experiences with and challenges of AMS; and the need to implement PLAC in the hospital.

Results

Only three physicians responded that they had protocols for initiating and maintaining warfarin dosing. Having protocols for venous thromboembolism (VTE) risk assessment, VTE prophylaxis and treatment, bleeding risk assessment, and contraindication to anticoagulant therapy were reported by seven, six, four, and three participants, respectively. Lack of trained healthcare professionals and a separate AMS clinic, inconsistency in INR testing and anticoagulant availability, and longer appointment times were the biggest challenges of the existing AMS, according to 80% of respondents. Fourteen patient respondents indicated that their satisfaction with the AMS was affected by long wait times and inconsistent availability of anticoagulants and INR testing. The head of the laboratory stated that the facilities for INR testing are inadequate and affect the quality of AMS and customer satisfaction, and supplemented by the head of the pharmacy by adding irregularities of supplies and inadequate counseling on anticoagulants. Respondents suggested that there is a need to establish a PLAC with well-adopted standard operating procedures, qualified manpower, adequate training of assigned staff, and sustained supply of anticoagulants and INR testing.

Conclusion

The hospital’s AMS is not optimal to provide adequate services during the study period. Based on these findings and recommendations, the supporting literature, and the experiences of other facilities, the PLAC was established in TASH.

American College of Gastroenterology-Canadian Association of Gastroenterology Clinical Practice Guideline: Management of Anticoagulants and Antiplatelets During Acute Gastrointestinal Bleeding and the Periendoscopic Period

We conducted systematic reviews of predefined clinical questions and used the Grading of Recommendations, Assessment, Development and Evaluations approach to develop recommendations for the periendoscopic management of anticoagulant and antiplatelet drugs during acute gastrointestinal (GI) bleeding and the elective endoscopic setting. The following recommendations target patients presenting with acute GI bleeding: For patients on warfarin, we suggest against giving fresh frozen plasma or vitamin K; if needed, we suggest prothrombin complex concentrate (PCC) compared with fresh frozen plasma administration; for patients on direct oral anticoagulants (DOACs), we suggest against PCC administration; if on dabigatran, we suggest against the administration of idarucizumab, and if on rivaroxaban or apixaban, we suggest against andexanet alfa administration; for patients on antiplatelet agents, we suggest against platelet transfusions; and for patients on cardiac acetylsalicylic acid (ASA) for secondary prevention, we suggest against holding it, but if the ASA has been interrupted, we suggest resumption on the day hemostasis is endoscopically confirmed. The following recommendations target patients in the elective (planned) endoscopy setting: For patients on warfarin, we suggest continuation as opposed to temporary interruption (1-7 days), but if it is held for procedures with high risk of GI bleeding, we suggest against bridging anticoagulation unless the patient has a mechanical heart valve; for patients on DOACs, we suggest temporarily interrupting rather than continuing these; for patients on dual antiplatelet therapy for secondary prevention, we suggest temporary interruption of the P2Y12 receptor inhibitor while continuing ASA; and if on cardiac ASA monotherapy for secondary prevention, we suggest against its interruption. Evidence was insufficient in the following settings to permit recommendations. With acute GI bleeding in patients on warfarin, we could not recommend for or against PCC administration when compared with placebo. In the elective periprocedural endoscopy setting, we could not recommend for or against temporary interruption of the P2Y12 receptor inhibitor for patients on a single P2Y12 inhibiting agent. We were also unable to make a recommendation regarding same-day resumption of the drug vs 1-7 days after the procedure among patients prescribed anticoagulants (warfarin or DOACs) or P2Y12 receptor inhibitor drugs because of insufficient evidence.

American College of Gastroenterology-Canadian Association of Gastroenterology Clinical Practice Guideline: Management of Anticoagulants and Antiplatelets During Acute Gastrointestinal Bleeding and the Periendoscopic Period

We conducted systematic reviews of predefined clinical questions and used the Grading of Recommendations, Assessment, Development and Evaluations approach to develop recommendations for the periendoscopic management of anticoagulant and antiplatelet drugs during acute gastrointestinal (GI) bleeding and the elective endoscopic setting. The following recommendations target patients presenting with acute GI bleeding: For patients on warfarin, we suggest against giving fresh frozen plasma or vitamin K; if needed, we suggest prothrombin complex concentrate (PCC) compared with fresh frozen plasma administration; for patients on direct oral anticoagulants (DOACs), we suggest against PCC administration; if on dabigatran, we suggest against the administration of idarucizumab, and if on rivaroxaban or apixaban, we suggest against andexanet alfa administration; for patients on antiplatelet agents, we suggest against platelet transfusions; and for patients on cardiac acetylsalicylic acid (ASA) for secondary prevention, we suggest against holding it, but if the ASA has been interrupted, we suggest resumption on the day hemostasis is endoscopically confirmed. The following recommendations target patients in the elective (planned) endoscopy setting: For patients on warfarin, we suggest continuation as opposed to temporary interruption (1-7 days), but if it is held for procedures with high risk of GI bleeding, we suggest against bridging anticoagulation unless the patient has a mechanical heart valve; for patients on DOACs, we suggest temporarily interrupting rather than continuing these; for patients on dual antiplatelet therapy for secondary prevention, we suggest temporary interruption of the P2Y12 receptor inhibitor while continuing ASA; and if on cardiac ASA monotherapy for secondary prevention, we suggest against its interruption. Evidence was insufficient in the following settings to permit recommendations. With acute GI bleeding in patients on warfarin, we could not recommend for or against PCC administration when compared with placebo. In the elective periprocedural endoscopy setting, we could not recommend for or against temporary interruption of the P2Y12 receptor inhibitor for patients on a single P2Y12 inhibiting agent. We were also unable to make a recommendation regarding same-day resumption of the drug vs 1-7 days after the procedure among patients prescribed anticoagulants (warfarin or DOACs) or P2Y12 receptor inhibitor drugs because of insufficient evidence.

Application of fresh frozen plasma transfusion in the management of excessive warfarin-associated anticoagulation

Warfarin is a commonly used oral anticoagulant. Patients with artificial valve replacement, atrial fibrillation, pulmonary embolism, deep vein thrombosis, and other diseases require long-term anticoagulant oral treatment with warfarin. As warfarin exhibits prompt action with long maintenance time, it has become a key drug for the treatment of patients at risk of developing thrombosis or thromboembolism. Warfarin is a bican coumarin anticoagulant, that exhibits competitive action against vitamin K as its mechanism of action, thereby inhibiting the synthesis of coagulation factors—predominantly the vitamin K-dependent coagulation factors II, VII, IX, and X—in hepatocytes. Long-term warfarin is known to significantly increase the risk of organ bleeding in some patients, while some patients may need to reverse the anticoagulation effect. For instance, patients scheduled for emergency or invasive surgery may require rapid anticoagulation reversal. During such medical circumstances, fresh frozen plasma (FFP) is clinically used for the reversal of excess warfarin-associated anticoagulation, as it contains all the coagulation factors that can alleviate the abnormal blood anticoagulation status in such patients. Accordingly, this article aims to perform an in-depth review of relevant literature on the reversal of warfarin with FFP, and insightful deliberation of the application and efficacy of this clinical intervention.

Use of Prothrombin Complex Concentrate in Oral Anticoagulant-Associated Major Bleeding

Severe bleeding remains the most significant adverse effect associated with both warfarin and the direct oral anticoagulant agents. Due to the life-threatening nature of these bleeds, knowledge and understanding of agents that are able to rapidly overcome the anticoagulation effects of these medications is paramount to their use. Worldwide, the most commonly used agent for this indication is prothrombin complex concentrate (PCC). This review summarizes the evidence on the use of PCC in this population and provides practical information regarding patient-specific administration considerations.

Immunothrombosis and the molecular control of tissue factor by pyroptosis: prospects for new anticoagulants

The interplay between innate immunity and coagulation after infection or injury, termed immunothrombosis, is the primary cause of disseminated intravascular coagulation (DIC), a condition that occurs in sepsis. Thrombosis associated with DIC is the leading cause of death worldwide. Interest in immunothrombosis has grown because of COVID-19, the respiratory disease caused by SARS-CoV-2, which has been termed a syndrome of dysregulated immunothrombosis. As the relatively new field of immunothrombosis expands at a rapid pace, the focus of academic and pharmacological research has shifted from generating treatments targeted at the traditional 'waterfall' model of coagulation to therapies better directed towards immune components that drive coagulopathies. Immunothrombosis can be initiated in macrophages by cleavage of the non-canonical inflammasome which contains caspase-11. This leads to release of tissue factor (TF), a membrane glycoprotein receptor that forms a high-affinity complex with coagulation factor VII/VIIa to proteolytically activate factors IX to IXa and X to Xa, generating thrombin and leading to fibrin formation and platelet activation. The mechanism involves the post-translational activation of TF, termed decryption, and release of decrypted TF via caspase-11-mediated pyroptosis. During aberrant immunothrombosis, decryption of TF leads to thromboinflammation, sepsis, and DIC. Therefore, developing therapies to target pyroptosis have emerged as an attractive concept to counteract dysregulated immunothrombosis. In this review, we detail the three mechanisms of TF control: concurrent induction of TF, caspase-11, and NLRP3 (signal 1); TF decryption, which increases its procoagulant activity (signal 2); and accelerated release of TF into the intravascular space via pyroptosis (signal 3). In this way, decryption of TF is analogous to the two signals of NLRP3 inflammasome activation, whereby induction of pro-IL-1β and NLRP3 (signal 1) is followed by activation of NLRP3 (signal 2). We describe in detail TF decryption, which involves pathogen-induced alterations in the composition of the plasma membrane and modification of key cysteines on TF, particularly at the location of the critical, allosterically regulated disulfide bond of TF in its 219-residue extracellular domain. In addition, we speculate towards the importance of identifying new therapeutics to block immunothrombotic triggering of TF, which can involve inhibition of pyroptosis to limit TF release, or the direct targeting of TF decryption using cysteine-modifying therapeutics.

Real-life contemporary vitamin K antagonist is still associated with very low time in therapeutic range despite strict international normalized ratio monitoring: Results of big data analysis

WHAT IS KNOWN AND OBJECTIVE

This study aimed to determine the results of INR monitoring in patients on vitamin K antagonists (VKAs) and the time in therapeutic range (TTR) in 'real-world' settings.

METHODS

Retrospective analysis of 836,857 INR measurements performed in adults from February 2010 to August 2015 in two districts in the French Brittany region.

RESULTS

Of the 836,857 INR measurements, 94.9% were ordered by general practitioners and 2.0% by cardiologists. The number of tests increased by 10-year age categories up to the age-group of 80-90 years. The number of INR measurements increased from 169,636 in 2011 to 176,184 in 2012, but then decreased slightly to 162,597 in 2013 and 164,427 in 2014. Mean coefficient of variation of INR was 19.0%, and mean TTR was 29.0%. TTR was higher in women than in men (31% vs. 18%), in older than in younger patients (19.1% at 40 years and 38.6% at 100 years) and in patients with arrhythmias than in those with deep vein thrombosis/pulmonary embolism (44.4% versus 19.4%) (p < 10^-5 for each comparison). Median interval between INR measurements was 14 days [7-28]; it was prolonged in men vs women, rural vs urban regions, older vs younger patients and when requested by GPs vs cardiologists. The interval was shorter for patients with INR outside the therapeutic range versus patients with INR within the therapeutic range (9 days [5-21] vs. 18 days [10-29], p < 10^-10 ).

WHAT IS NEW AND CONCLUSION

VKAs are still frequently prescribed in this era of direct oral anticoagulants. The low TTR cannot be explained by inadequate INR monitoring.

Comparison of Warfarin Initiation at 3 mg Versus 5 mg for Anticoagulation of Patients with Mechanical Mitral Valve Replacement Surgery: A Prospective Randomized Trial

Background

The increased warfarin sensitivity observed after mechanical mitral valve replacement (MVR) operations dictates clinical discretion in warfarin dose initiation. Evidence is still lacking with regard to anticoagulation management of MVR patients.

Objective

This study aimed to compare initiating warfarin at the recommended dosing regimen versus empirically lowered doses intended to account for the variation in warfarin sensitivity.

Methods

A prospective, single-blind, randomized, comparative study was conducted in postoperative MVR patients. Patients were randomly assigned to either the 5 mg group (n = 25) or the 3 mg group (n = 25) and were initiated on a 5 or 3 mg warfarin dose, respectively. Time to target international normalized ratio (INR), time in therapeutic range, occurrence of bleeding/thromboembolic events, and cost of bridging with enoxaparin were assessed for both groups.

Results

Target INR was achieved earlier in the 5 mg group than in the 3 mg group (p = 0.033), with a mean ± SD of 5.3 ± 2.0 and 6.6 ± 2.0, respectively (95% confidence interval of the mean difference 1.022–1.890). Bleeding events did not differ significantly between the two groups. The cost of enoxaparin consumption per patient was significantly higher in the 3 mg group versus the 5 mg group (p = 0.002).

Conclusions

The initiation of warfarin at a 5 mg dose in MVR patients was more efficacious than the 3 mg dose in terms of time to reach the target INR. Moreover, the cost of enoxaparin bridging was significantly reduced with a 5 mg warfarin initiation dose. Bleeding events were comparable.

ClinicalTrials.gov ID

NCT04235569, 22 January 2020.

Pharmacist monitoring of direct oral anticoagulants for American Indians and Alaska Natives in the outpatient setting

BACKGROUND

Direct oral anticoagulants (DOACs) call into question the role of traditional pharmacist-run clinics, and few studies have described the incorporation of DOAC's into traditional anticoagulation management services (AMS) OBJECTIVE: To describe the incorporation of DOACs into a pharmacist-run AMS for American Indian and Alaska Native (AI/AN) patients and determine outcomes related to adherence, follow-up, and pharmacist interventions.

PRACTICE DESCRIPTION

Traditional AMS embedded in ambulatory clinic. Warfarin managed by pharmacists under a collaborative practice agreement with supervising physician.

PRACTICE INNOVATION

DOACs incorporated into AMS by transitioning warfarin patients to rivaroxaban and apixaban and managing new patients with DOAC. Follow-up occurred via phone call and at longer intervals.

EVALUATION METHODS

Single-center, retrospective, observational analysis of AI/AN patients who were followed up by pharmacy AMS. The outcomes measured include adherence to DOAC therapy, number of telephonic encounters versus face-to-face visits, frequency of follow-up, types of interventions made at each visit, and an estimate of face-to-face clinic time savings.

RESULTS

A total of 50 patients were included for analysis. The average medication possession ratio was 91%. The majority of visits occurred over the phone (59%), and most follow-up visits occurred every 3 months (62%). The top 3 most frequent interventions were adherence education, initial DOAC education, and education on use of nonsteroidal anti-inflammatory drugs.

PRACTICE IMPLICATIONS

Traditional AMS can evolve by incorporating DOACs and maintaining follow-up.

CONCLUSION

Pharmacist monitoring of DOACs may promote high levels of adherence and lead to time savings by reducing the amount of time spent in traditional AMS.

Efficacy and safety of activated prothrombin complex concentrate for the reversal of vitamin K antagonist major bleeding

Data on the use of activated prothrombin complex concentrate (aPCC) for the management of warfarin associated major bleeding is sparse. The objective of the study was to assess the achievement of effective clinical hemostasis using aPCC in patients presenting with major bleeding while on warfarin. We also assessed the safety of the drug. This retrospective study was conducted at a tertiary care teaching center in the USA where patients with major bleeding while receiving warfarin, and received aPCC were included. Efficacy of aPCC in achieving effective hemostasis was assessed according to the International Society of Thrombosis and Hemostasis Scientific and Standardization Subcommittee criteria. Efficacy was also assessed by achieving INR < 1.5 after treatment. The primary safety endpoint was the occurrence of any thromboembolic complications. A total of 67 patients were included in the study. The most common site for bleeding was intracerebral hemorrhage (n = 37, 55.2%), followed by gastrointestinal bleed (n = 26, 38.8%). Clinical hemostasis was achieved in 46 (68.7%) patients and of the 21 (31.3%) patients who did not achieve clinical hemostasis, 16 died. Thirty nine (58.2%) patients achieved INR < 1.5. Five (7.5%) patients developed thromboembolic complications. This study suggests that the use of aPCCs is effective in achieving effective hemostasis in patients on warfarin presenting with major bleeding.

Comparison of clinical pharmacogenetic recommendations across therapeutic areas

OBJECTIVES

Evaluations from pharmacogenetics implementation programs at major US medical centers have reported variability in the clinical adoption of pharmacogenetics across therapeutic areas. A potential cause for this variability may involve therapeutic area-specific differences in published pharmacogenetics recommendations to clinicians. To date, however, the potential for differences in clinical pharmacogenetics recommendations by therapeutic areas from prominent US guidance sources has not been assessed. Accordingly, our objective was to comprehensively compare essential elements from clinical pharmacogenetics recommendations contained within Clinical Pharmacogenetics Implementation Consortium guidelines, US Food and Drug Administration drug labels and clinical practice guidelines from US professional medical organizations across therapeutic areas.

METHODS

We analyzed clinical pharmacogenetics recommendation elements within Clinical Pharmacogenetics Implementation Consortium guidelines, US Food and Drug Administration drug labels and professional clinical practice guidelines through 05/24/19.

RESULTS

We identified 606 unique clinical pharmacogenetics recommendations, with the most recommendations involving oncology (217 recommendations), hematology (79), psychiatry (65), cardiovascular (43) and anesthetic (37) medications. Within our analyses, we observed considerable variability across therapeutic areas within the following essential pharmacogenetics recommendation elements: the recommended clinical management strategy; the relevant genetic biomarkers; the organizations providing pharmacogenetics recommendations; whether routine genetic screening was recommended; and the time since recommendations were published.

CONCLUSIONS

On the basis of our results, we infer that observed differences in clinical pharmacogenetics recommendations across therapeutic areas may result from specific factors associated with individual disease states, the associated genetic biomarkers, and the characteristics of the organizations providing recommendations.

Comparison of 3-factor versus 4-factor prothrombin complex concentrate for emergent warfarin reversal: a systematic review and meta-analysis

Background

Patients requiring emergent warfarin reversal (EWR) have been prescribed three-factor prothrombin complex concentrate (PCC3) and four-factor prothrombin complex concentrate (PCC4) to reverse the anticoagulant effects of warfarin. There is no existing systematic review and meta-analysis of studies directly comparing PCC3 and PCC4.

Methods

The primary objective of this systematic review and meta-analysis was to determine the effectiveness of achieving study defined target INR goal after PCC3 or PCC4 administration. Secondary objectives were to determine the difference in safety endpoints, thromboembolic events (TE), and survival during the patients’ hospital stay. Random-effects meta-analysis models were used to estimate the odds ratios (OR), and heterogeneity associated with the outcomes. The Newcastle-Ottawa Scale was used to assess study quality, and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed.

Results

Ten full-text manuscripts and five abstracts provided data for the primary and secondary outcomes. Patients requiring EWR had more than three times the odds of reversal to goal INR when they were given PCC4 compared to PCC3 (OR = 3.61, 95% CI: 1.97–6.60, p < 0.001). There was no meaningful clinical association or statistically significant result between PCC4 and PCC3 groups in TE (OR = 1.56, 95% CI: 0.83–2.91, p = 0.17), or survival during hospital stay (OR = 1.34, 95% CI: 0.81–2.23, p = 0.25).

Conclusion

PCC4 is more effective than PCC3 in meeting specific predefined INR goals and has similar safety profiles in patients requiring emergent reversal of the anticoagulant effects of warfarin.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12873-022-00568-x.

Management of Coagulopathy in Bleeding Patients

Early recognition of coagulopathy is necessary for its prompt correction and successful management. Novel approaches, such as point-of-care testing (POC) and administration of coagulation factor concentrates (CFCs), aim to tailor the haemostatic therapy to each patient and thus reduce the risks of over- or under-transfusion. CFCs are an effective alternative to ratio-based transfusion therapies for the correction of different types of coagulopathies. In case of major bleeding or urgent surgery in patients treated with vitamin K antagonist anticoagulants, prothrombin complex concentrate (PCC) can effectively reverse the effects of the anticoagulant drug. Evidence for PCC effectiveness in the treatment of direct oral anticoagulants-associated bleeding is also increasing and PCC is recommended in guidelines as an alternative to specific reversal agents. In trauma-induced coagulopathy, fibrinogen concentrate is the preferred first-line treatment for hypofibrinogenaemia. Goal-directed coagulation management algorithms based on POC results provide guidance on how to adjust the treatment to the needs of the patient. When POC is not available, concentrate-based management can be guided by other parameters, such as blood gas analysis, thus providing an important alternative. Overall, tailored haemostatic therapies offer a more targeted approach to increase the concentration of coagulation factors in bleeding patients than traditional transfusion protocols.

The continued decline of plasma transfusions in Taiwan: An 11-year population-based study

BACKGROUND AND OBJECTIVES

In Taiwan, plasma use per capita ranks among the highest in the world. We aimed to describe the trends in usage after the introduction of new hospital accreditation standards that evaluate compliance with institutional plasma transfusion guidelines.

MATERIALS AND METHODS

We identified hospitalizations receiving plasma between 2007 and 2017 from the national health insurance database. We estimated plasma transfusions per thousand capita. The risk ratio of transfusion rates among hospitalizations in 2017 compared to 2007 was estimated using logistic regression.

RESULTS

The total number of plasma transfusions declined from 964,408 in 2007 to 659,828 in 2017, yielding a rate of 28.00 per thousand capita. The proportion of hospitalizations receiving plasma declined by 38%, from 3.89% (95% confidence interval: 3.86%-3.91%) to 2.62% (2.61%-2.64%). Gastroenterology (16.4%) and general surgery (15.3%) accounted for the largest proportions of plasma usage. Within these two services, liver diseases were the top diagnoses needing plasma use. For hospitalized patients with liver diseases, approximately 40% of plasma units were administered to patients with neither noticeable bleeding nor red blood cells transfusions. Among these patients, almost 50% received plasma with an international normalized ratio trigger of less than 1.50. The use of potential alternative therapies or anticoagulants remained quite low during this period.

CONCLUSION

Plasma utilization rates during hospitalizations continuously declined over 11 years. However, inappropriate plasma use remained high, while the use of alternative therapies remained low in services such as gastroenterology. To improve the appropriateness of plasma transfusions, patient blood management should be implemented in the near future.

PAD Inhibitors as a Potential Treatment for SARS-CoV-2 Immunothrombosis

Since the discovery of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in December 2019, the virus's dynamicity has resulted in the evolution of various variants, including the delta variant and the more novel mu variant. With a multitude of mutant strains posing as challenges to vaccine efficacy, it is critical that researchers embrace the development of pharmacotherapeutics specific to SARS-CoV-2 pathophysiology. Neutrophil extracellular traps and their constituents, including citrullinated histones, display a linear connection with thrombotic manifestations in COVID-19 patients. Peptidylarginine deiminases (PADs) are a group of enzymes involved in the modification of histone arginine residues by citrullination, allowing for the formation of NETs. PAD inhibitors, specifically PAD-4 inhibitors, offer extensive pharmacotherapeutic potential across a broad range of inflammatory diseases such as COVID-19, through mediating NETs formation. Although numerous PAD-4 inhibitors exist, current literature has not explored the depth of utilizing these inhibitors clinically to treat thrombotic complications in COVID-19 patients. This review article offers the clinical significance of PAD-4 inhibitors in reducing thrombotic complications across various inflammatory disorders like COVID-19 and suggests that these inhibitors may be valuable in treating the origin of SARS-CoV-2 immunothrombosis.

COVID-19 and coagulopathy

The SARS-CoV-2 is a new coronavirus responsible for the COVID-19 disease and has caused the pandemic worldwide. A large number of cases have overwhelmed the healthcare system worldwide. The COVID-19 infection has been associated with a heightened risk of thromboembolic complications. Various mechanisms are leading to the high thrombotic risk in COVID-19 patients such as inflammation, endotheliitis, hyperviscosity, and hypercoagulability. We searched PubMed, EMBASE, and CINAHL from January 2020 to December 2020. We used the following search terms: COVID-19, coagulopathy, and thrombosis. We reviewed the epidemiology, clinical features, mechanisms, and treatment of COVID-19-associated coagulopathy.

Role of Direct Oral Anticoagulation Agents as Thromboprophylaxis in Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is an autoimmune disorder that causes venous, arterial and small-vessel thrombosis, pregnancy loss, and premature birth. Cardiac valvular disease, renal thrombotic microangiopathy, thrombocytopenia, hemolytic anemia, and cognitive impairment are some of its other clinical symptoms. Antiphospholipid antibodies cause endothelial cells, monocytes, and platelets to become activated, as well as an increase in tissue factor and thromboxane A2. Complement activation might play a key function in pathogenesis. Long-term oral anticoagulation is used to treat thrombosis, and individuals having arterial episodes should be treated quickly. Patients with systemic lupus erythematosus (SLE), as well as those with solely obstetric antiphospholipid syndrome, should get primary thromboprophylaxis. Obstetric care is based on a combination of medical and obstetric high-risk management, as well as aspirin and heparin therapy. Possible supplementary therapy for this condition is hydroxychloroquine. Statins, rituximab, and novel anticoagulant medicines are all potential future treatments for non-pregnant individuals with antiphospholipid syndrome. We aim to review the role of direct-acting oral anticoagulants (DOACs) as thromboprophylactic drugs in the treatment of APS in this article. The treatment of venous thromboembolism has been transformed by a new class of DOACs. These drugs, such as rivaroxaban, function by inhibiting factor Xa directly. Not only do they have known anticoagulant actions, but they also obviate the need for dosage monitoring and modification, in contrast to warfarin. We conducted an exhaustive literature search of PubMed/MEDLINE and Google Scholar Indexes using the keywords "Antiphospholipid syndrome," "thromboprophylaxis," and "oral anticoagulants" up to September 2021. We found that DOACs have been shown to be non-inferior to warfarin in a variety of anticoagulation situations in a number of high-powered clinical studies. In many hypercoagulable conditions such as APS, DOACs are quickly establishing themselves as first-line therapy. This article is focused on comprehensively reviewing the mechanism of action of DOACs, their role as thromboprophylactic drugs, risks and complications of DOACs, and comparing their efficacy with the standard treatment protocol and warfarin.

Acute Stroke Treatment in an Anticoagulated Patient: When Is Thrombolysis an Option?

Purpose of Review

Direct oral anticoagulants (DOACs: the factor Xa inhibitors rivaroxaban, apixaban, and edoxaban and the direct thrombin inhibitor dabigatran) are the mainstay of stroke prevention in patients with non-valvular atrial fibrillation (AF). Nevertheless, there is a residual stroke risk of 1–2% per year despite DOAC therapy. Intravenous thrombolysis (IVT) reduces morbidity in patients with ischemic stroke and improves functional outcome. Prior DOAC therapy is a (relative) contraindication for IVT but emerging evidence supports its use in selected patients.

Recent Findings

Recent observational studies highlighted that IVT in patients on prior DOAC therapy seems feasible and did not yield major safety issues. Different selection criteria and approaches have been studied including selection by DOAC plasma levels, non-specific coagulation assays, time since last intake, and prior reversal agent use. The optimal selection process is however not clear and most studies comprised few patients.

Summary

IVT in patients taking DOAC is a clinically challenging scenario. Several approaches have been proposed without major safety issues but current evidence is weak. A patient-oriented approach balancing potential benefits of IVT (i.e., amount of salvageable penumbra) against expected bleeding risk including appropriate monitoring of anticoagulant activity seem justified.

Anticoagulation Treatment in Venous Thromboembolism: Options and Optimal Duration

Venous thromboembolism (VTE), clinically presenting as deep-vein thrombosis (DVT) or pulmonary embolism (PE), constitutes a major global healthcare concern with severe complications, long-term morbidity and mortality. Although several clinical, genetic and acquired risk factors for VTE have been identified, the molecular pathophysiology and mechanisms of disease progression remain poorly understood. Anticoagulation has been the cornerstone of therapy for decades, but there still are uncertainties regarding primary and secondary VTE prevention, as well as optimal therapy duration. In this review we discuss the role of factor Xa in coagulation cascade and the different choices of anticoagulation therapy based on patients' predisposing risk factors and risk of event recurrence. Further, we compare newer agents to traditional anticoagulation treatment, based on most recent studies and guidelines.

Nano optical and electrochemical sensors and biosensors for detection of narrow therapeutic index drugs

For the first time, a comprehensive review is presented on the quantitative determination of narrow therapeutic index drugs (NTIDs) by nano optical and electrochemical sensors and biosensors. NTIDs have a narrow index between their effective doses and those at which they produce adverse toxic effects. Therefore, accurate determination of these drugs is very important for clinicians to provide a clear judgment about drug therapy for patients. Routine analytical techniques have limitations such as being expensive, laborious, and time-consuming, and need a skilled user and therefore  the nano/(bio)sensing technology leads to high interest.

Thromboembolic Complications After Receipt of Prothrombin Complex Concentrate

Purpose: Patients presenting with life-threatening bleeding associated with oral anticoagulants (OACs) are challenging with few available treatments. Prothrombin complex concentrate (PCC) is an option for OAC reversal in the setting of life-threatening bleeding with a relatively benign safety profile. Little is known about the risk of developing thromboembolic complications (TEC) in patients receiving PCC who were previously anticoagulated. The aim of this study is to characterize the rate of TEC after receipt of PCC. Methods: All adult patients who received 4-Factor PCC for life-threatening bleeding were retrospectively evaluated over a 2-year time period. Data collected included anticoagulant and indication, bleeding source, PCC dose, INR, and TEC within 14 days of PCC dose, including venous thromboembolism (VTE), acute myocardial infarction, and ischemic stroke. Results: Three hundred thirty-three patients received 383 PCC doses. Of these, 55 (16.5%) patients developed TEC, including VTE, ischemic stroke, and acute myocardial infarction. There was increased rivaroxaban use in patients who developed TEC (25.4% vs 12.2%; P = .011). Additionally, there were more patients who had anticoagulation for a previous TEC in those who developed a new TEC (38.2% vs 23.4%; P = .022). Lastly, there was a higher rate of TEC in those who received >1 dose of PCC (21.8% vs 7.9%; P = .002). Conclusion: PCC administration in the setting of life-threatening bleeding is not benign. Risk of TEC increases in patients who have rivaroxaban reversal, receive a repeat dose of PCC, and have a TEC indication for their anticoagulation and these factors should be further investigated.

Anticoagulation Control, Outcomes, and Associated Factors in Patients with Atrial Fibrillation Receiving Warfarin at Tertiary Care Hospital in Ethiopia

Anticoagulation is the cornerstone in the prevention of stroke in atrial fibrillation. This study aimed at assessing the anticoagulation control and outcome and predictive factors in atrial fibrillation patients on warfarin therapy. A retrospective chart review was used to evaluate patients with atrial fibrillation who were on warfarin during two years follow up at the anticoagulation clinic of the hospital. The time in therapeutic range (TTR) was calculated using Rosendaal's method. Data were analyzed using SPSS software version 25. Univariable and multivariable analyses were computed to determine factors affecting TTR and bleeding events. We included 300 patients in this study. The mean percentage TTR was 42.03 ± 18.75. Only 38 (12.67%) patients achieved a TTR of above 65%. The average international normalized ratio (INR) testing frequency was 35 days (16.3-67.2 days). Taking 1 or 2 drugs along with warfarin was found to be better in achieving good TTR as compared to taking more than two drugs (p = .014). Having heart failure was associated with a 2.45 times odds of poor anticoagulation control (TTR< 65%) (p = .047). Male study participants were 2.53 times more likely of developing bleeding events than females (p = .009). Bleeding events were observed in 62 (20.67%) patients. Study participants, who didn't have Diabetic Mellitus and those not receiving aspirin were at lower odds developing bleeding events (AOR = .196; C.I. = .060-.638; p−.007 and AOR = .099; CI. = .024-.416; p−.02), respectively. In summary, the time spent in the therapeutic range was minimal in this population of patients with AF on warfarin managed at a hospital run anticoagulation clinic in Ethiopia. Moreover, the number of co-prescribed medications, and having heart failure were associated with poor TTR. Bleeding events were high and affected by male sex, having DM comorbidity, and using aspirin.

Association between time to therapeutic INR and length of stay following mechanical heart valve surgery

BACKGROUND

Warfarin is the only oral anticoagulant approved for use following mechanical valve surgery (MeVS). Patients may experience prolonged hospital length of stay (LOS) following MeVS awaiting an appropriate warfarin effect. We aimed to determine whether an association exists between time to achieve the first therapeutic international normalized ratio (INR) and LOS following MeVS.

MATERIALS AND METHODS

Retrospective single center cohort study. We included consecutive adult patients undergoing elective MeVS from 2013 to 2018. Landmark analyses and multivariable regression with time-updated INR were used to estimate the association between time to therapeutic INR (TTI) and LOS.

RESULTS

Among 384 patients (median age: 51 years, interquartile range [IQR]: 41-57; 58.3% male), the median TTI was 4 days (IQR: 2-5). Thirty seven percent of patients were discharged with a subtherapeutic INR, many on bridging anticoagulation or with an INR close to target. Those achieving therapeutic INR had an increased rate of hospital discharge (adjusted hazard ratio: 2.17; 95% confidence interval: 1.71-2.76; p < .0001). Attainment of a therapeutic INR anytime between postoperative Days 4 and 13 was significantly associated with a shorter LOS.

CONCLUSIONS

Prolonged time to achieve a therapeutic INR was independently associated with prolonged LOS. Future strategies aimed at improving attainment of therapeutic INR following MeVS may reduce hospital LOS.

Replacement of traditional prothrombin time monitoring with the new Fiix prothrombin time increases the efficacy of warfarin without increasing bleeding. A review article

The antithrombotic effect of vitamin K antagonists (VKA) depends on controlled lowering of the activity of factors (F) II and X whereas reductions in FVII and FIX play little role. PT-INR based monitoring, however, is highly influenced by FVII, which has the shortest half-life of vitamin K-dependent coagulation factors. Hence, variability in the anticoagulant effect of VKA may be partly secondary to an inherent flaw of the traditional monitoring test itself. The Fiix prothrombin time (Fiix-PT) is a novel test that is only sensitive to reductions in FII and FX and is intended to stabilize the VKA effect. Two clinical studies have now demonstrated that when warfarin is monitored with the Fiix-PT based normalized ratio (Fiix-NR) instead of PT-INR, anticoagulation is stabilized and less testing and fewer dose adjustments are needed. Furthermore, the relative risk of thromboembolism was reduced by 50-56% in these studies without an increase in major bleeding.

Extending INR testing intervals in warfarin patients at a multi-center anticoagulation clinic

Warfarin has been used as an anticoagulant by millions of patients due to its effectiveness, availability, and low cost. Evidence on the safe extension of international normalized ratio (INR) testing frequency remains an area of interest, especially during the recent COVID-19 pandemic. The purpose of this study is to safely extend INR testing intervals in patients throughout a multisite, system-wide anticoagulation clinic. Updates were made to the pharmacist’s collaborative practice agreement (CPA) and nurse protocol to optimize practice and allow INR testing interval extension up to a maximum of 8-weeks. The primary outcome was the change in duration between INR tests (INR testing interval) measured before and after providing staff education on clinic updates. The mean duration between INR tests (SD) was 23.69 days (11.29) in the pre-intervention period and 25.58 days (13.91) in the post-intervention period. During the COVID-19 pandemic (post2), intervals were extended further to 27.81 days (14.96), demonstrating a statistically significant increase in INR testing interval from pre-intervention to post-intervention and to post2 (p < 0.001 and p < 0.001, respectively). A secondary outcome indicated the mean time in therapeutic range (SD) showed no significant difference in pre-intervention 70.11% (25.95) versus post-intervention of 69.76% (25.69) with a difference of − 0.35% (29.93) (p = 0.956) or versus the post2 of 68.82% (27.20) with a difference of − 1.29% (33.20) (p = 0.120). This study showed that changes to the CPA and protocol allowed for a significant increase in INR testing interval while simultaneously maintaining a mean time in therapeutic range > 60% for the clinic population.

Drugs in phase I and II clinical development for the prevention of stroke in patients with atrial fibrillation

INTRODUCTION

Atrial fibrillation is the most frequently diagnosed cardiac arrhythmia globally and is associated with ischemic stroke and heart failure. Patients with atrial fibrillation are typically prescribed long-term anticoagulants in the form of either vitamin K antagonists or non-vitamin K antagonist oral anticoagulants; however, both carry a potential risk of adverse bleeding.

AREAS COVERED

This paper sheds light on emerging anticoagulant agents which target clotting factors XI and XII, or their activated forms - XIa and XIIa, respectively, within the intrinsic coagulation pathway. The authors examined data available on PubMed, Scopus, and the clinical trials registry of the United States National Library of Medicine (www.clinicaltrials.gov).

EXPERT OPINION

Therapies targeting factors XI or XII can yield anticoagulant efficacy with the potential to reduce adverse bleeding. Advantages for targeting factor XI or XII include a wider therapeutic window and reduced bleeding. Long-term follow-up studies and a greater understanding of the safety and efficacy are required. Atrial fibrillation is a chronic disease and therefore the development of oral formulations is key.

Stability of vitamin K antagonist anticoagulation after COVID-19 diagnosis

BACKGROUND

Coagulopathy has been reported in severely ill patients with coronavirus disease 2019 (COVID-19). It is unclear whether outpatients with COVID-19 who are treated with vitamin K antagonists (VKAs) have unstable anticoagulation.

OBJECTIVE

To assess the stability of VKA therapy in patients with COVID-19 through a case-crossover study.

METHODS

Between February and July 2020, we included patients who tested positive for COVID-19 from two anticoagulant clinics in the Netherlands. We collected international normalized ratios (INRs) determined between 26 weeks before infection and 12 weeks after. Time in therapeutic range (TTR) and the variance growth rate (VGR) were calculated within patients.

RESULTS

Fifty-one patients with COVID-19 (mean age, 84 years) were included, of whom 15 (29%) were men. Mean TTR in the 26 weeks before COVID-19 was 80% (95% confidence interval [CI], 75-85) compared to 59% (95% CI, 51-68) in the 6 weeks after infection. Mean TTR difference was -23% (95% CI, -32 to -14) with a time above therapeutic range of 38% (95% CI, 30-47) in the 6 weeks after infection. The TTR rose again to 79% (95% CI, 69-89) between 6 and 12 weeks after infection. Also, VGR increased, with a mean increase of 4.8 (95% CI, 2.1-7.5) in the 6 weeks after infection. In the 26 weeks before infection, we registered 19 of 641 (3%) of INR ≥5.0 compared with 35 of 247 (14%) in the 6 weeks after (risk ratio, 4.4; 95% CI, 2.7-7.3).

CONCLUSIONS

COVID-19 is associated with a strong decrease in TTR and in therapeutic stability in patients taking VKAs. Additional monitoring in these patients is advised to maximize therapeutic stability.

Barriers and facilitators for optimizing oral anticoagulant management: Perspectives of patients, caregivers, and providers

BACKGROUND

Oral anticoagulants (OACs) are very commonly prescribed for prevention of serious vascular events, but are also associated with serious medication-related bleeding. Mitigation of harm is believed to require high-quality OAC management. This study aimed to identify barriers and facilitators for optimal OAC management from the perspective of patients, caregivers and healthcare providers.

METHODS

Using a qualitative descriptive study design, we conducted five focus groups, three with patients and caregivers and two with health care providers, in two health regions in Southwestern Ontario. An expert facilitator led the discussions using a semi-structured interview guide. Each session was digitally recorded, transcribed verbatim and anonymized. Transcripts were analyzed in duplicate using conventional content analysis.

RESULTS

Forty-two (19 patients, 7 caregivers, and 16 providers including physicians, nurses and pharmacists) participated. More than half of the patients received OAC for the treatment of venous thromboembolism (57.9%) and the majority (94.7%) were on chronic therapy (defined as >3 years). Data analysis organized codes describing barriers and facilitators into 4 main themes-medication-related, patient-related, provider-related, and system-related. Barriers highlighted were problems with medication access due to cost, patient difficulties with adherence, knowledge and adjusting their lifestyles to OAC therapy, provider expertise, time for adequate communication amongst providers and their patients, and health care system inadequacies in supporting communications and monitoring. Facilitators identified generally addressed these barriers.

CONCLUSIONS

Many barriers to optimal OAC management exist even in the era of DOACs, many of which are amenable to facilitators of improved care coordination, patient education, and adherence monitoring.

Methodological quality of systematic reviews comprising clinical practice guidelines for cardiovascular risk assessment and management for noncardiac surgery

BACKGROUND

Cardiac assessment in noncardiac surgery clinical practice guidelines should be supported by the highest-quality evidence such as that offered by systematic reviews. Currently, the methodological and reporting quality of these studies remains unknown.

METHODS

We used PubMed to search for all clinical practice guidelines related to perioperative cardiovascular patients undergoing noncardiac surgery from 2010 to 2021. The included clinical practice guidelines were analysed for all systematic reviews and meta-analyses. The primary objective of this study was to determine reporting and methodological quality using the PRISMA (Preferred Reporting Instrument for Systematic Reviews and Meta-Analyses) and AMSTAR-2 (A Measurement Tool to Assess Systematic Reviews-2) instruments. Our secondary objective was to compare systematic reviews conducted by the Cochrane Collaboration with non-Cochrane studies.

RESULTS

Three clinical practice guidelines were included in our study. Within these, 78 systematic reviews were included. PRISMA completion ranged from 34.8% to 100.0% with a mean of 76.9%. AMSTAR-2 completion ranged from 15.6% to 96.9% with a mean of 58.0%. Fifty-four systematic reviews underpinned a clinical practice guidelines recommendation, of which 25 were rated 'critically low' by AMSTAR-2 appraisal. Cochrane systematic reviews typically performed better than non-Cochrane studies, but were a minority of the included studies (10/78).

CONCLUSION

We found deficiencies in several key areas regarding the methodological and reporting qualities of systematic reviews included in cardiac assessment in noncardiac surgery clinical practice guidelines. As these clinical practice guidelines are instrumental to clinical decision-making and patient care in cardiac assessment in noncardiac surgery, we advocate for improved reporting quality among systematic reviews cited as supportive evidence for these recommendations.

Retrospective pharmacogenetic analysis of a pediatric patient under anticoagulant treatment: Clinical case

We present the clinical case of a 10-year-old patient diagnosed with dilated cardiomyopathy who registered INR values above 10 upon receiving standard doses of acenocoumarol, as well as other values reported as uncoagulable, forcing the discontinuation and restart of treatment more than once. Expected and stable INR levels were achieved after more than 30 days of treatment, surprisingly with half the recommended dose for a patient of her age and weight. We decided to conduct a retrospective pharmacogenomic analysis including nucleotide genetic polymorphisms (SNPs) with different degrees of association with the dose/response to antivitamin K (AVK) drugs: rs2108622 (gene CYP4F2), rs9923231, rs7294 (gene VKORC1), rs1799853, and rs1057910 (CYP2C9 gene) using TaqMan® RT-PCR. The patient was homozygous for rs9923231 (VKORC1) and heterozygous for rs2108622 (CYP4F2),a genetic profile strongly associated with a requirement of lower AVK doses as shown by national and international evidence. In conclusion, the pharmacogenetic analysis confirmed that this patient’s genetic conditions, involving low expression of the VKA therapeutic target, required a lower dose than that established in clinical protocols as recommended by the Food and Drug Administration (FDA) and the PharmGKB® for coumarin drugs. A previous genotypic analysis of the patient would have allowed reaching the therapeutic range sooner, thus avoiding potential bleeding risks. This shows the importance of pharmacogenetic analyses for highly variable treatments with a narrow therapeutic range.

Evaluation of Changing Vena Cava Filter Use and Inpatient Hospital Mortality from 2016-2019: A Single-Institution Quality Improvement Project

Objective

To evaluate the changing trends of vena cava filter (VCF) insertion and determine whether changes in VCF use affected inpatient mortality.

Patients and Methods

A quality improvement project at Mayo Clinic, Rochester, Minnesota, tracks the type and reason for VCF insertions from January 1, 2016, through December 31, 2019, to facilitate appropriate retrieval. The rate of VCF insertions was compared with inpatient mortality rates, normalized for patient volumes using the number of hospital inpatient discharges.

Results

A total of 698 VCFs were placed in 695 patients: 2016 (n=243), 2017 (n=156), 2018 (n=156), and 2019 (n=120). The rate of VCF insertions (per 1000 inpatient discharges) was 4.02 in 2016, 2.91 in 2017, 2.54 in 2018, and 1.93 in 2019. Mean ± SD age at placement was 62±16.4 years and 59.2% (413/698) were men. Most VCFs were retrievable (85.1%; 594/698) and were placed for treatment (78.4%; 547/698) indications (acute venous thromboembolism within 3 months). The rate of VCF insertions was compared with the inpatient mortality rate (per 100 inpatient discharges) and remained stable (1.83 in 2016, 1.79 in 2017, 1.83 in 2018, and 1.76 in 2019) despite the significant decline in VCF use.

Conclusion

Data from this quality improvement study demonstrate a reduction of more than 50% in the use of VCFs from 2016 through 2019 at a large academic hospital. These changes are difficult to attribute to any single change in clinical use and there was no appreciable increase in the inpatient hospital mortality rate associated with this decrease in VCF filter use.

Time to Peak International Normalized Ratio Rise in Acute and Acute-on-Chronic Warfarin Overdoses

ABSTRACT

Guidelines exist on the management of supratherapeutic/subtherapeutic international normalized ratio (INR) values for patients on warfarin. However, there is a paucity of the literature relating to an acute overdose of warfarin. This is a retrospective cohort study for all acute and acute-on-chronic (AOC) warfarin overdoses reported to the Maryland Poison Center in patients ≥12 years between January 1st, 2000, until October 31st, 2019, managed in a health care facility. The primary outcome was to determine the time after presentation to peak INR. Secondary outcomes included risk factors associated with INR >10 and describing patient characteristics. A total of 163 overdoses were included, 68 acute and 95 AOC. In patients who did not receive reversal therapies, INR peaked at a median value of 3.8 (interquartile range 2.6-5.5) between 24 and 36 hours. The median time to phytonadione was 22.0 hours. Most patients received phytonadione (62.0%), with fewer receiving blood products (16.6%). The median warfarin dose ingested was 75 mg. The AOC group had a greater mean age (56 vs. 43 years), median INR value (2.4 vs. 1.4), and men (62.1% vs. 41.2%). Factors associated with an INR > 10 included initial INR and reported quantity ingested. Peak INR was greater in the AOC than the acute overdose group (6.1 vs. 3.4), although the bleeding rate was similar. Peak INR values after warfarin overdose occur between 24 and 36 hours after presentation. Initial INRs and reported quantity ingested may be useful to predict those needing treatment.

[Clinical analysis of head and neck malignant tumor patients with postoperative venous thromboembolism]

Objective:To investigate the incidence, risk factors, prevention and treatment of venous thromboembolism（VTE） after head and neck malignant tumor surgery. Methods:From February 2014 to February 2020, a total of 889 patients with head and neck malignant tumor treated in the Department of Otolaryngology Head and Neck Surgery of the Third Xiangya Hospital of Central South University were selected as the research objects. 16 patients with VTE were selected as the observation group, and 30 patients were randomly selected as the control group from 873 patients without VTE. The related evaluation indexes were analyzed by univariate and multivariate logistic regression. Results:①VTE occurred in 16 cases of 889 patients with head and neck malignancy, and the incidence of VET in head and neck malignant tumor patients was 1.80%. ② Univariate analysis showed that postoperative VTE was related to gender, age, BMI, preoperative PICC, operation time and bed rest time. Multivariate logistic regression analysis indicated that age≥60 years old（OR=0.087, 95%CI: 0.012-0.643）, preoperative PICC（OR=0.133, 95%CI: 0.021-0.856） and operation time≥3 h（OR=0.119, 95%CI: 0.016-0.889） was an independent risk factor of VTE after head and neck malignant tumor operation （P<0.05）. Conclusion:VTE is a serious complication after operation for head and neck malignant tumor. The risk factors of postoperative VTE include age≥60 years, preoperative PICC and operation time≥3 h. Early prevention and timely treatment are the key to reduce postoperative VTE mortality.

Prevalence and the factors associated with oral anticoagulant use among nursing home residents

WHAT IS KNOWN AND OBJECTIVE

Anticoagulants are indicated for treatment and prevention of several clinical conditions. Prior studies have examined anticoagulant utilization for specific indications and in community-dwelling populations. Decision-making regarding anticoagulant prescribing in the nursing home setting is particularly challenging because advanced age and clinical complexity places most residents at increased risk for adverse drug events. To estimate the prevalence of oral anticoagulant (OAC) use (overall, warfarin, direct oral anticoagulants (DOACs)) and identify factors associated with oral anticoagulant use among the general population of residents living in nursing homes.

METHODS

This point prevalence study was conducted among 506,482 residents in US nursing homes on 31 October 2016 who were enrolled in Medicare fee-for-service. Covariates including demographics, clinical conditions, medications, cognitive impairment and functional status were obtained from Minimum Data Set 3.0 assessments and Medicare Part A and D claims. Oral anticoagulant use was identified using dispensing dates and days supply information from Medicare Part D claims. Robust Poisson models estimated adjusted prevalence ratios (aPR) for associations between covariates and 1) any anticoagulant use, and 2) DOAC versus warfarin use.

RESULTS AND DISCUSSION

Overall, 11.8% of residents used oral anticoagulants. Among users, 44.3% used DOACs. Residents with body mass index (BMI) ≥40 kg/m² (aPR: 1.66; 95% CI: 1.61 -1.71), with functional dependency in activities of daily living, polypharmacy and higher CHA₂ DS₂ -VASc risk ischaemic stroke scores, had a higher prevalence of oral anticoagulant use. Women (aPR: 0.78; 95% CI: 0.76-0.79), residents with limited life expectancy (aPR 0.80; 95% CI: 0.76-0.83), those with moderate-to-severe cognitive impairment (aPR: 0.67; 95% CI: 0.65-0.68), those using NSAIDs or antiplatelets, and non-white racial/ethnic groups had a lower prevalence of anticoagulant use. Residents with higher levels of polypharmacy, BMI and age had a lower prevalence of DOAC use (versus warfarin).

WHAT IS NEW AND CONCLUSION

Approximately one in eight general nursing home residents use oral anticoagulants and among oral anticoagulant users, only slightly more residents used warfarin than DOACs. The lower prevalence of anticoagulation among women and non-white racial/ethnic groups raises concerns of potential inequities in quality of care. Lower oral anticoagulant use among residents with limited life expectancy suggests possible deprescribing at the end of life. Further research is needed to inform resident-centred shared decision-making that explicitly considers treatment goals and individual-specific risks and benefits of anticoagulation at all stages of the medication use continuum.

Lignosulfonic Acid Sodium Is a Noncompetitive Inhibitor of Human Factor XIa

The anticoagulant activity of lignosulfonic acid sodium (LSAS), a non-saccharide heparin mimetic, was investigated in this study. LSAS is a relatively safe industrial byproduct with similar polyanionic characteristics to that of heparin. Human plasma clotting assays, fibrin polymerization testing, and enzyme inhibition assays were exploited to investigate the anticoagulant activity of LSAS. In normal human plasma, LSAS selectively doubled the activated partial thromboplastin time (APTT) at ~308 µg/mL. Equally, LSAS doubled APTT at ~275 µg/mL in antithrombin-deficient plasma. Yet, LSAS doubled APTT at a higher concentration of 429 µg/mL using factor XI-deficient plasma. LSAS did not affect FXIIIa-mediated fibrin polymerization at 1000 µg/mL. Enzyme assays revealed that LSAS inhibits factor XIa (FXIa) with an IC₅₀ value of ~8 μg/mL. LSAS did not inhibit thrombin, factor IXa, factor Xa, factor XIIIa, chymotrypsin, or trypsin at the highest concentrations tested and demonstrated significant selectivity against factor XIIa and plasmin. In Michaelis–Menten kinetics, LSAS decreased the V_MAX of FXIa hydrolysis of a tripeptide chromogenic substrate without significantly changing its K_M indicating an allosteric inhibition mechanism. The inhibitor also disrupted the generation of FXIa–antithrombin complex, inhibited factor XIIa-mediated and thrombin-mediated activation of the zymogen factor XI to FXIa, and competed with heparin for binding to FXIa. Its action appears to be reversed by protamine sulfate. Structure–activity relationship studies demonstrated the advantageous selectivity and allosteric behavior of LSAS over the acetylated and desulfonated derivatives of LSAS. LSAS is a sulfonated heparin mimetic that demonstrates significant anticoagulant activity in human plasma. Overall, it appears that LSAS is a potent, selective, and allosteric inhibitor of FXIa with significant anticoagulant activity in human plasma. Altogether, this study introduces LSAS as a promising lead for further development as an anticoagulant.

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.

Derivation and validation of predictors of oral anticoagulant-related adverse events in seniors transitioning from hospital to home

INTRODUCTION

Oral anticoagulant (OAC)-related adverse events are high post-hospitalization. We planned to develop and validate a prediction model for OAC-related harm within 30 days of hospitalization.

METHODS

We undertook a population-based study of adults aged ≥66 years who were discharged from hospital on an OAC from September 2010 to March 2015 in Ontario, Canada. The primary outcome was a composite of time to first hospitalization or emergency department visit for a hemorrhagic or thromboembolic event, or mortality within 30 days of hospital discharge. Cox proportional hazards regression was used to build the model.

RESULTS

We included 120,721 patients of which 5423 experienced the outcome. Most patients were aged ≥75 years (59.5%) and were female (55.6%). Sixty percent of the cohort had a follow-up visit with a healthcare provider within 7 days of discharge. Patients discharged on a direct acting OAC versus warfarin (apixaban: Hazard Ratio [HR] 0.82, 95% confidence interval [CI] 0.71-0.94; dabigatran: HR 0.73, 95% CI 0.63-0.84; rivaroxaban: HR 0.79, 95% CI 0.71-0.88), were prevalent users of the dispensed OAC versus incident users (HR 0.82, 95% CI 0.69-0.96), had a joint replacement in the past 35 days (HR 0.40, 95% CI 0.33-0.50) or major surgery during index hospital stay (HR 0.69, 95% CI 0.60-0.80) had a lower risk for the outcome. The Cox model was stable with acceptable discrimination but poor goodness-of-fit.

CONCLUSIONS

A model for OAC-related harm in the early post-discharge period was developed. External validation studies are required to understand the model's poor calibration.

Characterization of dynamic changes in Matrix Gla Protein (MGP) gene expression as function of genetic risk alleles, osteoarthritis relevant stimuli, and the vitamin K inhibitor warfarin

OBJECTIVE

We here aimed to characterize changes of Matrix Gla Protein (MGP) expression in relation to its recently identified OA risk allele rs1800801-T in OA cartilage, subchondral bone and human ex vivo osteochondral explants subjected to OA related stimuli. Given that MGP function depends on vitamin K bioavailability, we studied the effect of frequently prescribed vitamin K antagonist warfarin.

METHODS

Differential (allelic) mRNA expression of MGP was analyzed using RNA-sequencing data of human OA cartilage and subchondral bone. Human osteochondral explants were used to study exposures to interleukin one beta (IL-1β; inflammation), triiodothyronine (T3; Hypertrophy), warfarin, or 65% mechanical stress (65%MS) as function of rs1800801 genotypes.

RESULTS

We confirmed that the MGP risk allele rs1800801-T was associated with lower expression and that MGP was significantly upregulated in lesioned as compared to preserved OA tissues, mainly in risk allele carriers, in both cartilage and subchondral bone. Moreover, MGP expression was downregulated in response to OA like triggers in cartilage and subchondral bone and this effect might be reduced in carriers of the rs1800801-T risk allele. Finally, warfarin treatment in cartilage increased COL10A1 and reduced SOX9 and MMP3 expression and in subchondral bone reduced COL1A1 and POSTN expression.

DISCUSSION & CONCLUSIONS

Our data highlights that the genetic risk allele lowers MGP expression and upon OA relevant triggers may hamper adequate dynamic changes in MGP expression, mainly in cartilage. The determined direct negative effect of warfarin on human explant cultures functionally underscores the previously found association between vitamin K deficiency and OA.

Incidence of Acute Ischemic Stroke in Hospitalized Patients With Atrial Fibrillation Who Had Anticoagulation Interruption: A Retrospective Study

Background

Atrial fibrillation (AF) is one of the leading causes of acute ischemic stroke requiring anticoagulation. Many patients experience treatment interruption in the hospital setting. The aim of this study was to evaluate the effect of anticoagulation interruption on short-term risk of ischemic stroke in hospitalized patients with AF.

Methods

We performed a retrospective medical record review using the Hospital Corporation of America (HCA) database. We included patients admitted to our institution between December 2015 and December 2018 who had a prior history of AF. Patients were excluded if they had ischemic stroke, hemorrhagic stroke, history venous thromboembolism or mechanical valve on admission. We compared the incidence of ischemic stroke in patients in whom anticoagulation was interrupted for more than 48 h to those who continued anticoagulation.

Results

A total of 2,277 patients with history of AF were included in the study. In this cohort, 79 patients (3.47%) had anticoagulation interruption of more than 48 h during their hospital stay. There was no difference in incidence of stroke between the interruption and no interruption groups (1.27% (n = 1) vs. 0.23% (n = 5), P = 0.19). Interruption of anticoagulation did not associate with a significant increase in the risk of in-hospital ischemic stroke. CHA₂DS₂VASc score was a strong predictor of in-hospital stroke risk regardless of anticoagulation interruption (odds ratio: 7.199, 95% confidence interval: 2.920 - 17.751).

Conclusion

In this study, the in-hospital incidence of ischemic stroke in patients with AF did not significantly increase by short-term anticoagulation interruption.

Warfarin maintenance dose prediction for Chinese after heart valve replacement by a feedforward neural network with equal stratified sampling

Patients requiring low-dose warfarin are more likely to suffer bleeding due to overdose. The goal of this work is to improve the feedforward neural network model's precision in predicting the low maintenance dose for Chinese in the aspect of training data construction. We built the model from a resampled dataset created by equal stratified sampling (maintaining the same sample number in three dose-groups with a total of 3639) and performed internal and external validations. Comparing to the model trained from the raw dataset of 19,060 eligible cases, we improved the low-dose group's ideal prediction percentage from 0.7 to 9.6% and maintained the overall performance (76.4% vs. 75.6%) in external validation. We further built neural network models on single-dose subsets to invest whether the subsets samples were sufficient and whether the selected factors were appropriate. The training set sizes were 1340 and 1478 for the low and high dose subsets; the corresponding ideal prediction percentages were 70.2% and 75.1%. The training set size for the intermediate dose varied and was 1553, 6214, and 12,429; the corresponding ideal prediction percentages were 95.6, 95.1%, and 95.3%. Our conclusion is that equal stratified sampling can be a considerable alternative approach in training data construction to build drug dosing models in the clinic.