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

Coexistent antiphospholipid syndrome and myeloproliferative neoplasm

Antiphospholipid syndrome (APS) and myeloproliferative neoplasms (MPN) are associated with an increased risk of thrombosis. The optimal management of patients with coexistent APS and MPN has not been defined. A single centre and systematic literature review of patients with coexistent APS and MPN was performed. Cases were divided into two groups based on whether they met international consensus criteria for APS. Of the 12 studies identified, eight were excluded (leaving five of a total 54 patients), as although antiphospholipid antibodies (aPL) were documented, the diagnosis of APS was not conclusively demonstrated. Another ten patients with definite APS were identified at our centre. Fifteen patients (ten females, five males) were therefore included in this analysis (eleven definite APS and four highly likely), median age 44 (range: 13-71) years. Nine had polycythaemia vera and six, essential thrombocythaemia. Thirteen of the 15 patients (86.7%) had thrombotic APS (seven with initial venous events and six arterial) and two (13.3%) had obstetric APS. Nine patients were single-positive, and six double-positive for aPL. None were triple aPL-positive. Four patients at our centre had recurrent thrombotic/obstetric events, including while on anticoagulation/antiplatelet treatment.

The experience of Hamad General Hospital collaborative anticoagulation clinic in Qatar during the COVID-19 pandemic

Hamad General Hospital Anticoagulation Clinic is one of the largest collaborative-practice clinics of its type in Qatar. The patients being followed at this clinic are typically complex and vulnerable. During the coronavirus disease 2019 pandemic, measures were implemented at the clinic to minimize the exposure of patients and healthcare providers to the acute respiratory syndrome coronavirus-2 and to promote social distancing. These measures included extending INR-recall period, transitioning to direct oral anticoagulant drugs whenever feasible, home visits to elderly and immunocompromised patients for INR testing, establishing an anticoagulation hotline, and relocation of warfarin dispensing from the main pharmacy to the anticoagulation clinic. In addition, the clinic shifted its multidisciplinary team meetings onto an online platform using Microsoft Teams. Telehealth consultations were extensively utilized to closely follow up with the patients and ensure that anticoagulation efficacy and safety remained optimal. The aim of this paper is to share our experience and describe the measures adopted by the clinic as part of the Hamad Medical Corporation response to the emerging situation.

Impact of body mass index on 90-day warfarin requirements: a retrospective chart review

Background:

Rates of obesity continue to rise worldwide as evidenced in the 2017 Centers for Disease Control and Prevention (CDC) report that indicated over 35% of United States (US) citizens are obese, with Louisiana ranked as the fifth most obese state in America. Since large clinical trials tend to exclude obese patients, health care providers are faced with concerns of under- or overdosing these patients on warfarin.

Methods:

This retrospective chart review evaluated patients who reported to a community anticoagulation clinic for warfarin management between 1 June 2017 and 30 September 2017. Along with baseline demographics, chronic use of drugs that have clinically significant interactions with warfarin, social activity such as tobacco use and alcohol consumption, were collected. Body mass indexes (BMI) were collected and categorized according to the World Health Organization definitions as follows: Normal (BMI 18–24.9 kg/m²), Overweight (25–29.9 kg/m²), Obesity Class I (30–34.9 kg/m²), Obesity Class II (35–39.9 kg/m²), Obesity Class III (⩾40 kg/m²). The primary outcome was the mean 90-day warfarin dose required to maintain “intermediate control” or “good control” of international normalized ratio (INR), stratified by BMI classifications. The secondary outcome was the time in therapeutic range (TTR) stratified by BMI classifications.

Results:

A total of 433 patient encounters were included in this study. There was a total of 43 encounters in the Normal BMI category, 111 Overweight encounters, 135 Obesity Class I encounters, 45 Obesity Class II encounters, and 99 Obesity Class III encounters. Approximately 63% of the study population were male, and over 90% the patients were African American. The Obesity Class I and Obesity Class II class required an average of 11.47 mg and 17.10 mg more warfarin, respectively, to maintain a therapeutic INR when compared with the Normal BMI category. These findings were statistically significant with p values of 0.007 and <0.001, respectively. Additionally, upon comparing the Overweight BMI category with the Obesity Class II category, there was a mean warfarin dose difference of 11.22 mg (p = 0.010) more in Obesity Class II encounters to maintain a therapeutic INR. In the secondary analysis of TTR, Overweight category encounters had the highest TTR, whereas encounters in the Normal BMI category had the lowest TTR.

Conclusion:

As BMI increases, there is an increased chronic warfarin requirement to maintain “intermediate control” or “good control” of INR between 2 and 3 in an ambulatory care setting.

Evaluation of the algorithm of Anticlot Assistant: an anticoagulant management system based on mobile health technology

The purpose is to evaluate the algorithm of Anticlot Assistant, a novel anticoagulant management system based on mobile health technology which was developed to facilitate patient self-management. The eligible patients managed warfarin therapy with usual care, following the prescriptions of the doctors. The actual prescriptions of doctors and the virtual recommendations by Anticlot Assistant were compared and analyzed. There were no significant differences between the next test dates recommended by Anticlot Assistant and those prescribed by doctors. The mean warfarin dosage prescribed by doctors was lower than that recommended by Anticlot Assistant (2.74 ± 1.17 vs. 2.79 ± 1.21 mg, 95% confidence interval for the difference: -0.01--0.09, P = 0.019, n = 139), resulting in the international normalized ratio a high time below the therapeutic range (TTR) (29.9 ± 17.9%), and a low time above TTR [0.0% (0.0-18.7%)]. A mixed linear model revealed that 'the variations of the dosages prescribed by doctors from those recommended by Anticlot Assistant' were positively correlated with 'variations of next international normalized ratios from TTR' after controlling for other factors (estimate of the effect = 0.231, 95% confidence interval: 0.034-0.428, P = 0.022). Anticlot Assistant can mimic the doctors' prescriptions for the next test date and the warfarin dosages recommended by Anticlot Assistant might be more reasonable than those prescribed by doctors, which indicated that the algorithm was reliable and it was possible for the patients to manage warfarin therapy themselves with the aid of Anticlot Assistant.

A Retrospective Analysis Comparing Post-Operative Bleeding with Various Doses of Aspirin after Lower Extremity Joint Arthroplasty or Revision

STUDY OBJECTIVE

Previous studies have shown that aspirin is noninferior to other anticoagulation therapies in preventing postoperative venous thromboembolism following lower extremity arthroplasty or revision; however, its optimal dosing for this indication is less clear. This study aims to compare the odds of bleeding between different aspirin dosages following lower extremity joint arthroplasty or revision.

DESIGN

This is a 3-year retrospective multi-center cohort study across the United States and its territories.

SETTING

This study included patients admitted for total hip or knee arthroplasty or revision and were treated with prophylactic aspirin.

PATIENTS, INTERVENTION, MEASUREMENTS

Patients were assigned to groups based on a total daily aspirin dose of 81, 162, 325, or 650 mg. Data were analyzed for postsurgical bleeding and thromboembolism events occurring during the initial admission and up to 40 days following surgery. Other exploratory variables included type of surgery, hip or knee arthroplasty, length of stay, and patient demographic data.

MAIN RESULTS

Among 53,848 patients receiving aspirin, 3922 received a total daily dose of 81 mg, 19,341 received a total daily dose of 162 mg, 5256 received a total daily dose of 325 mg, and 25,329 received a total daily dose of 650 mg. Bleeding occurred in 466 (0.87%) patients and venous thromboembolism (VTE) in 209 patients (0.39%). The odds of bleeding were compared using logistic regression, with the 650-mg dose as the reference group. None were statistically significant for bleeding between all studied aspirin doses: 81 mg (OR 1.12, 95% CI 0.83-1.51, p = 0.451), 162 mg (OR 0.83, 95% CI 0.67-1.03, p = 0.097), and 325 mg (OR 0.83, 95% CI 0.59-1.13, p = 0.245). The odds of VTE were also not statistically significant: 81 mg (OR 0.71, 95% CI 0.40-1.17, p = 0.181), 162 mg (OR 0.75 95% CI 0.54-1.03, p = 0.072), and 325 mg (OR 1.00, 95% CI 0.64-1.53, p = 0.989).

CONCLUSIONS

There were no significant differences in the odds of bleeding or venous thromboembolism among all studied aspirin dosages in patients receiving aspirin for thromboprophylaxis following lower extremity joint arthroplasty or revision.

The effects of anticoagulant therapy re-initiation after gastrointestinal bleeding: A systematic review and meta-analysis

WHAT IS KNOWN AND OBJECTIVE

Long-term anticoagulant/antithrombotic therapy is widely used for the management of thromboembolic conditions. Gastrointestinal bleeding is a common collateral manifestation of anticoagulant/antithrombotic therapy that complicates its administration. The continuation or discontinuation of anticoagulant/antithrombotic therapy after an episode of gastrointestinal bleeding has been a matter of debate. Despite recent positive reports from retrospective cohort studies suggesting a reduction in morbidity- and mortality-related outcomes with continued administration of anticoagulant/antithrombotic agents (even after gastrointestinal bleeding), no consensus or comparisons about the efficacies of continued or discontinued antithrombotic administration exist. Therefore, we developed this current state-of-evidence analysis evaluating the comparative effects of continuation and discontinuation of anticoagulant/antithrombotic drugs after gastrointestinal bleeding on the overall incidences of gastrointestinal bleeding, thromboembolic events and mortality events.

METHODS

We performed a systematic academic literature search according to the PRISMA guidelines across five databases: Web of Science, Embase, CENTRAL, Scopus and MEDLINE. Moreover, we conducted a random effect meta-analysis to compare the effects of continuation and discontinuation of anticoagulant/antithrombotic drugs after an event of gastrointestinal bleeding on the overall incidences of gastrointestinal bleeding, thromboembolic events and mortality events.

RESULTS

We found seven eligible studies (from 1397 candidates) with 2532 participants (mean age, 73.1 ± 4.1 years). Our meta-analysis revealed lower odds of thromboembolic events (OR, -0.21), mortality outcomes (OR, -0.39) and an increase in the incidence of gastrointestinal bleeding (OR, 2.4) in the group with continued anticoagulant/antithrombotic therapy than in the group discontinuing the therapy.

WHAT IS NEW AND CONCLUSION

We provide an updated evidence on the comparative effects between continuation and discontinuation of anticoagulant/antithrombotic drugs after gastrointestinal bleeding events based on the overall incidences of gastrointestinal bleeding, thromboembolic events and mortality events. This study reports confirm an overall lower incidence of thromboembolic events and mortality outcomes for the continuation group than for the discontinuation group.

Unexpected acute pulmonary embolism in an old COVID-19 patient with warfarin overdose: a case report

Background

Severe acute respiratory syndrome coronavirus 2 disease is strongly associated with a high incidence of thrombotic events. Anticoagulation could be a cornerstone in successfully managing severe forms of coronavirus disease 2019 (COVID-19). However, optimal anticoagulant dosing in elderly patients is challenging because of high risk of both thrombosis and bleeding.

Case summary

We present here the case of an 89-year-old patient receiving warfarin for atrial fibrillation and valvular heart disease, admitted to the intensive care unit for respiratory failure due to COVID-19. The patient presented with a severe epistaxis associated with warfarin overdose [international normalized ratio (INR) > 10]. After a successful initial reversal using vitamin K per os, INR values greatly fluctuated up to 10, requiring repeated administrations of vitamin K. Despite starting low-molecular-weight heparin therapy at therapeutic dose as soon as INR value was below 2.0, the patient further developed an acute bilateral and proximal pulmonary embolism concomitantly with a sharp D-dimer increase. The combination of azithromycin intake, a known inhibitor of CYP2C9, with the presence of CYP2C9*2 and −1639G>A VKORC1, two variants associated with warfarin hypersensitivity, have likely contributed to explain the warfarin overdose and the difficulty to reverse warfarin effect in this patient.

Discussion

This case report illustrates the complexity of COVID-19 pathophysiology and its management for physicians, especially in patients receiving vitamin K antagonists (VKAs). Infection, concurrent medication use, and pharmacogenetic factors involved in VKA metabolism and pharmacodynamics may lead to a loss of control of anticoagulation. Pulmonary embolism should still be considered in COVID-19 patients even with effective or overdosed anticoagulant therapy.

A meta-analysis of andexanet alfa and prothrombin complex concentrate in the treatment of factor Xa inhibitor-related major bleeding

Background

Andexanet alfa (andexanet) and prothrombin complex concentrate (PCC) are both reversal agents for major bleeding in patients using factor Xa inhibitors (FXaIs). Our aim was to evaluate the current evidence for the effectiveness and safety of andexanet and PCC in a systematic review and meta-analysis.

Objectives

Primary objective was hemostatic effectiveness. Secondary objectives were thromboembolic event rate and mortality.

Methods

A systematic review was performed in PubMed and Embase. Studies describing the effectiveness and/or safety of PCC or andexanet in patients with major bleeding using FXaIs were included. Meta-analysis was performed using a random-effects model.

Results

Seventeen PCC studies, 3 andexanet studies, and 1 study describing PCC and andexanet were included, comprising 1428 PCC-treated and 396 andexanet-treated patients. None of the included studies had control groups, hampering a pooled meta-analysis to compare the two reversal agents. Separate analyses for andexanet and PCC were performed. In subgroup analysis, the pooled proportion of patients with effective hemostasis in studies that used Annexa-4 criteria demonstrated a hemostatic effectiveness of 0.85 (95% confidence interval [CI], 0.80-0.90) in PCC and 0.82 (95% CI, 0.78-0.87) in andexanet studies. The pooled proportion of patients with thromboembolic events was 0.03 (95% CI, 0.02-0.04) in PCC and 0.11 (95% CI, 0.04-0.18) in andexanet studies.

Conclusion

Based on the available evidence with low certainty from observational studies, PCC and andexanet demonstrated a similar, effective hemostasis in the treatment of major bleeding in patients using FXaIs. Compared to PCC, the thromboembolic event rate appeared higher in andexanet-treated patients.

Polymorphism of the CYP2C9 and VKORC1 genes in patients on the public health system of a municipality in Southern Brazil

Background

Genetic factors can be responsible for part of the populational and interindividual differences observed in warfarin users.

Objectives

To identify occurrence of polymorphisms of the CYP2C9 and VKORC1 genes in patients taking warfarin and relate these profiles to their medication dosages and the Time in Therapeutic Range (TTR).

Methods

Monthly interviews were conducted for data collection. Data were collected on demographic characteristics and medications in use, especially warfarin, including reason for prescription and weekly dose. TTR was calculated as the percentage of days with international normalized ratio (INR) between 2 and 3. The CYP2C9 and VKORC1 genes were analyzed at a Human Genetics Laboratory.

Results

49 patients (74.2%) had polymorphisms of the CYP2C9 and/or VKORC1 genes; the remaining 17 (25.8%) did not have these polymorphisms. The average weekly dose of warfarin was lower among those who had a polymorphism for any of the genes compared to those who did not, with a significant difference (p = 0.035). The mean TTR was also lower among patients with polymorphism. However, the difference between the two groups was not significant for this variable (p = 0.438).

Conclusions

An association was observed between the polymorphisms and the warfarin doses taken by the patients. However, there was no association with adverse events or the time spent within the therapeutic range in this sample.

Pharmacometric modeling to explore 4F-PCC dosing strategies for VKA reversal in patients with INR below 2

The indicated dose of 4-factor prothrombin complex concentrate (4F-PCC) for urgent vitamin K antagonist (VKA) reversal in patients with an international normalized ratio (INR) of 2 to 4 is 25 IU/kg, but there is no indicated dose for INR <2. We explored 4F-PCC dosing strategies for baseline INR <2. Clinical trial data were used to develop pharmacometric models for Factor X (FX) and FII, accounting for covariates including baseline INR. FX and FII levels over time were simulated for mean baseline INR levels of the clinical trial participants plus baseline INRs 3.1, 1.9, and 1.6. For each INR, 200 virtual male patients were simulated to evaluate 4F-PCC doses of 35, 25, 20, 15, 12.5, and 10 IU/kg. Given an elevated bleeding risk with VKA therapy in Japanese vs Western populations, results were stratified by Japanese and non-Japanese patients. Target levels of FX and FII were ≥50% activity at 30 minutes after dosing in ≥80% of patients. FX- and FII-time models were developed with 1088 FX observations from 193 patients and 1074 FII observations from 192 patients. Model-based simulations indicated that at baseline INR 3.1, ≥80% of patients achieved ≥50% FX and FII activity with 25 IU/kg and 20 IU/kg 4F-PCC, respectively; at baseline INR 1.9, corresponding doses were 20 IU/kg and 15 IU/kg 4F-PCC, and at baseline INR 1.6, corresponding doses were 15 IU/kg, and 10 IU/kg 4F-PCC. Trends in Japanese and non-Japanese patients were similar. In conclusion, low 4F-PCC doses (15-20 IU/kg) may be sufficient to achieve hemostatic levels of FX and FII in Japanese and non-Japanese patients with baseline INR <2.

How I treat anticoagulant-refractory thrombotic antiphospholipid syndrome

The standard treatment of thrombotic antiphospholipid syndrome (APS) is lifelong oral anticoagulation with a vitamin K antagonist (VKA), generally warfarin. A minority of patients with APS rethrombose despite seemingly adequate anticoagulation. These patients are deemed anticoagulant refractory. The management of anticoagulant-refractory APS is largely empirical and extrapolated from other clinically similar situations. Further options include increased VKA anticoagulation intensity or alternative antithrombotic strategies, including low-molecular-weight heparin, fondaparinux, the addition of antiplatelet therapy, and consideration of vascular options. Patients with anticoagulant-refractory thrombotic APS may have APS-associated thrombocytopenia, which necessitates balancing the risk of recurrent thrombosis vs bleeding to achieve adequate anticoagulation. The multiple mechanisms involved in the generation of the thrombotic phenotype in APS suggest that anticoagulation alone may not control thrombosis. Thus, other modalities, including adjunctive treatment (hydroxychloroquine, statins, and vitamin D) for APS-related thrombosis, merit consideration, as do immunomodulatory therapy and complement inhibition. Patients with APS may have coexistent systemic lupus erythematosus, which adds to the complexity of managing their thromboembolic disease. However, with attention to detail and judicious application of the limited data, it is possible to minimize the morbidity resulting from anticoagulant-refractory thrombotic APS. Multicenter studies are required to guide the sequence of interventions and their comparative efficacy in patients with anticoagulant-refractory thrombotic APS.

Vitamin K antagonist anticoagulant usage is associated with increased incidence and progression of osteoarthritis

OBJECTIVES

Vitamin K is hypothesised to play a role in osteoarthritis (OA) pathogenesis through effects on vitamin K-dependent bone and cartilage proteins, and therefore may represent a modifiable risk factor. A genetic variant in a vitamin K-dependent protein that is an essential inhibitor for cartilage calcification, matrix Gla protein (MGP), was associated with an increased risk for OA. Vitamin K antagonist anticoagulants (VKAs), such as warfarin and acenocoumarol, act as anticoagulants through inhibition of vitamin K-dependent blood coagulation proteins. VKAs likely also affect the functioning of other vitamin K-dependent proteins such as MGP.

METHODS

We investigated the effect of acenocoumarol usage on progression and incidence of radiographic OA in 3494 participants of the Rotterdam Study cohort. We also examined the effect of MGP and VKORC1 single nucleotide variants on this association.

RESULTS

Acenocoumarol usage was associated with an increased risk of OA incidence and progression (OR=2.50, 95% CI=1.94-3.20), both for knee (OR=2.34, 95% CI=1.67-3.22) and hip OA (OR=2.74, 95% CI=1.82-4.11). Among acenocoumarol users, carriers of the high VKORC1(BB) expression haplotype together with the MGP OA risk allele (rs1800801-T) had an increased risk of OA incidence and progression (OR=4.18, 95% CI=2.69-6.50), while this relationship was not present in non-users of that group (OR=1.01, 95% CI=0.78-1.33).

CONCLUSIONS

These findings support the importance of vitamin K and vitamin K-dependent proteins, as MGP, in the pathogenesis of OA. Additionally, these results may have direct implications for the clinical prevention of OA, supporting the consideration of direct oral anticoagulants in favour of VKAs.

Weight-Based Dosing Versus a Fixed-Dose Regimen of 4-Factor Prothrombin Complex Concentrate in Obese Patients Requiring Vitamin K Antagonist Reversal

INTRODUCTION

Despite an increase in the use of fixed-dose protocols of 4-factor prothrombin complex concentrate (4F-PCC) for the reversal of vitamin K antagonists (VKAs), there remains a paucity of data in obese patients. In this study, we aimed to compare the proportion of patients attaining international normalized ratio (INR) goals using a weight-based dosing strategy versus a fixed-dose regimen of 4F-PCC.

METHODS

This was a retrospective study conducted in patients 18 years of age or older, weighing ≥ 100 kg, who received either a weight-based dose or fixed dose of 4F-PCC (2000 units) for the reversal of VKA, and had a documented baseline and post-treatment INR. The primary outcome was the proportion of patients achieving an INR of < 2 for all indications of warfarin reversal, except in patients with intracranial hemorrhage, where the goal was an INR of < 1.5.

RESULTS

A total of 44 patients met the inclusion criteria; 25 patients in the weight-based dosing group and 19 patients in the fixed-dose group. The median baseline INR was similar in both groups (weight-based dosing group 3.2 [interquartile range {IQR} 2.8-3.7] vs fixed-dose group 3.0 [IQR 2.7-4.9], p = 1). The median post-treatment INR was significantly lower in the weight-based dosing group compared to the fixed-dose group (1.3 [IQR 1.2-1.5] vs 1.6 [IQR 1.5-1.9], p < 0.01). However, there was no significant difference in the primary outcome between both groups (weight-based dosing strategy 84% vs fixed dose strategy 90%, p = 0.68).

CONCLUSION

Our findings suggest that a fixed-dose regimen of 2000 units in obese patients weighing ≥ 100 kg is adequate to achieve these INR goals.

The effect of reinforcing an educational programme using telephone follow-up on health-related quality of life of individuals using warfarin: A randomised controlled trial

OBJECTIVES

To evaluate the effect of reinforcing an educational programme through telephone follow-up on health-related quality of life and anxiety and depression symptoms in individuals starting warfarin therapy.

BACKGROUND

Educational interventions have improved quality of life in individuals using warfarin. Few studies have examined the addition of telephone follow-up to enhance educational interventions.

DESIGN

Randomised controlled trial in outpatient setting.

METHODS

Hospitalised adults starting warfarin therapy who agreed to participate received an educational programme about the warfarin treatment. At discharge, they were randomised to receive either five telephone follow-up calls (intervention) or no telephone calls (controls). Both groups were evaluated for health-related quality of life (using Duke Anticoagulation Satisfaction Scale) and symptoms of anxiety and depression (using Hospital Anxiety and Depression Scale) at three and six months post-discharge. Groups were compared at each time by independent-samples t test, and over time by repeated-measures analysis of variance, with time (three and six months), groups (intervention and control) and an interaction between time and group as factors. Level of significance was set at 0.05. The Consolidated Standards of Reporting Trials was used for reporting.

RESULTS

Fifty-two individuals (26 per group) completed the study. There were no statistical differences between groups in health-related quality of life, anxiety and depression symptoms, at both times post-discharge. Participants who received follow-up telephone calls reported better positive psychological impact (a subscale of quality of life) than controls.

CONCLUSIONS

Reinforcing an educational programme with telephone follow-ups did not have an overall effect on health-related quality of life of individuals using warfarin but promoted positive psychological impact.

RELEVANCE TO CLINICAL PRACTICE

The low cost of reinforcing educational programmes with telephone calls and the improvement in positive psychological aspects indicate that this type of intervention is still a promising intervention that could be further investigated and improved.

Efficacy and Safety of the Fixed-Dose Versus Variable-Dose of 4-PCC for Vitamin K Antagonist Reversal: A Comprehensive Systematic Review and Meta-Analysis

BACKGROUND

The optimal dosing strategy of four-factor prothrombin complex concentrate (4F-PCC) for vitamin K antagonists (VKAs) reversal is unknown.

METHODS

We conducted systematic search on the PubMed, SCOPUS, and Embase databases from inception to December 2020 for clinical studies that compared the fixed-dose versus variable-dose of 4-PCC for VKAs reversal with at least one reported clinical outcome. The treatment effects were expressed as relative ratios (RR) with 95% confidence intervals (CIs) and pooled by a random-effects model.

RESULTS

Ten studies, including 988 patients, were included. Fixed-dose 4-PCC was associated with lower rate of mortality (RR= 0.65, 95% CI 0.47 to 0.9, p= 0.009), comparable rate of thromboembolic event (TEE) (RR= 1.10, 95%CI 0.44 to 2.80, p= 0.826), and lower goal INR reached (RR= 0.87, 95%CI 0.78 to 0.96, p= 0.007). Less 4-PCC cumulative dose, shorter duration of order-to-needle time, similar hospital length of stay, the comparable time required for INR reversal, higher post-4-PCC INR, and a higher need for additional dose were observed in fixed-dose.

CONCLUSIONS

The use of a fixed-dose of 4-PCC may be considered an effective and safe dosing strategy for VKAs reversal in various clinical situations. However, further well-designed, controlled studies should be conducted focusing on clinical outcomes to determine the optimal dose of 4-PCC for VKAs reversal.

Probable Interaction Between Warfarin and the Combination of Remdesivir With Dexamethasone for Coronavirus Disease 2019 (COVID-19) Treatment: A 2 Case Report

PURPOSE

To describe a potential drug interaction between warfarin and the combination of remdesivir with dexamethasone.

SUMMARY

Two male patients, a 71-year-old and 62-year-old presented to the emergency department for symptoms of coronavirus disease 2019 (COVID-19). Both patients were on long-term warfarin therapy with their most recent international normalized ratio (INR) prior to admission within their patient specific goal as managed by their outpatient Pharmacist. In both instances, the patients denied any changes in diet, lifestyle, or missed doses of medications upon admission interview. During admission, both patients experienced a marked elevation in INR within 24 to 48 hours of the initiation of remdesivir with dexamethasone for COVID-19 pneumonia directed therapy. The patients were both eventually stable and were instructed to continue warfarin monitoring and management under the direction of their outpatient Pharmacist upon discharge.

CONCLUSION

The underrecognized but probable interaction between warfarin in conjunction with remdesivir and dexamethasone warrants further analysis.

Utility of coagulation analyses to assess thromboprophylaxis with dalteparin in intensive care unit patients

BACKGROUND

The aim of this study was to evaluate the utility of coagulation analyses to assess thromboprophylaxis with dalteparin in intensive care unit (ICU) patients.

METHODS

Prospective observational study of ICU patients receiving dalteparin prophylaxis at Oslo University Hospital in Norway. Trough and peak antithrombin, protein C, anti-factor Xa activity (aFXa), d-dimer, thromboelastography, calibrated automated thrombogram and microparticles were analysed. Levels were compared in patients with and without venous thromboembolism (VTE), major bleeding, acute kidney injury (AKI) with use of renal replacement therapy (RRT) and variable dalteparin dose.

RESULTS

Among 50 included patients (76% male, mean age 62 years) five (10%) developed VTE and eight (16%) major bleeding. Median through aFXa level was 0.03 (0.02-0.05) IU/mL, and 48 (96%) of patients were within and two (4%) above target range. Peak aFXa level was 0.21 (0.13-0.29) IU/mL, the number of patients below, within and above prophylactic range were 21 (42%), 25 (50%) and four (8%). Peak aFXa levels were similar in patients with and without VTE (0.18 vs 0.21 IU/L, P = .72), major bleeding (0.22 vs 0.21 IU/mL, P = .38) and AKI with RRT (0.18 vs 0.24, P = .13), but lower in patients receiving dalteparin 5000 IU od compared to 7500 IU od (0.19 vs 0.30 IU/mL, P < .01).

CONCLUSIONS

Intensive care unit patients receiving dalteparin prophylaxis had half of patients within prophylactic peak aFXa target range. Peak aFXa levels was affected by administered dalteparin dose, but not presence of VTE, major bleeding or AKI with RRT.

Randomized, placebo-controlled trial of orally administered vitamin K1 for warfarin-associated coagulopathy in Chinese patients with mechanical heart valves

PURPOSE

Warfarin-associated coagulopathy commonly occurs in patients undergoing treatment with this anticoagulant. This trial aimed to determine the efficacy of using low-dose orally administered vitamin K₁ to lower international normalized ratio (INR) values into the target range in a cohort of Chinese patients with mechanical heart valves.

METHODS

This was a double-blind, placebo-controlled, randomized trial. Chinese patients with mechanical heart valves who were undergoing warfarin treatment and who had INR values from 4.0 to 10.0 without bleeding were the subjects of this study. These patients were randomized into two treatment groups and were orally administered either vitamin K₁ (2.5 mg) or placebo. Warfarin was discontinued in both groups until INR values were ≤ 2.5. INR values on the day following treatment were the primary study outcome, with INR values on the following days and adverse clinical events over a 3-month follow-up serving as secondary study outcomes.

RESULTS

In total, 80 patients were enrolled in the present study, and 40 patients each were assigned to the placebo and vitamin K1 treatment groups. Patients administered vitamin K₁ exhibited a quick reduction in INR values relative to patients administered placebo (29 of 40 [72.5%] vs. 0 of 44 [0%] patients exhibiting INR values from 1.5-2.5 on the day following treatment, respectively, p = 0.000). Lower bleeding incidence was observed among patients administered vitamin K₁ relative to those administered placebo during follow-up (4 [10%] vs. 12 [30%] patients, respectively, p = 0.045). There were no instances of thromboembolic complications or warfarin resistance in either group.

CONCLUSION

Low-dose oral vitamin K₁ can be effectively administered to Chinese patients with mechanical heart valves taking warfarin to rapidly reduce elevated INR values.

Drug-drug Interactions with Warfarin: A Systematic Review and Meta-analysis

AIM

The objective of this paper is to systematically review the literature on drug-drug interactions with warfarin, with a focus on patient-important clinical outcomes.

METHODS

MEDLINE, EMBASE, and the International Pharmaceutical Abstract (IPA) databases were searched from January 2004 to August 2019. We included studies describing drug-drug interactions between warfarin and other drugs. Screening and data extraction were conducted independently and in duplicate. We synthesized pooled odds ratios (OR) with 95% confidence intervals (CIs), comparing warfarin plus another medication to warfarin alone. We assessed the risk of bias at the study level and evaluated the overall certainty of evidence using GRADE.

RESULTS

Of 42,013 citations identified, a total of 72 studies reporting on 3,735,775 patients were considered eligible, including 11 randomized clinical trials and 61 observational studies. Increased risk of clinically relevant bleeding when added to warfarin therapy was observed for antiplatelet (AP) regimens (OR=1.74; 95% CI 1.56, 1.94), many antimicrobials (OR=1.63; 95% CI 1.45, 1.83), NSAIDs including COX-2 NSAIDs (OR=1.83; 95% CI 1.29, 2.59), SSRIs (OR=1.62; 95% CI 1.42, 1.85), mirtazapine (OR=1.75; 95% CI 1.30, 2.36), loop diuretics (OR=1.92; 95% CI 1.29, 2.86), and others. We found a protective effect of proton pump inhibitors (PPIs) against warfarin-related gastrointestinal (GI) bleedings (OR=0.69; 95% CI 0.64, 0.73). No significant effect on thromboembolic events or mortality of any drug group used with warfarin was found, including single or dual AP regimens.

CONCLUSIONS

This review found low to moderate certainty evidence supporting the interaction between warfarin and a small group of medications, which result in increased bleeding risk. PPIs are associated with reduced hospitalization for upper GI bleeding for patients taking warfarin. Further studies are required to better understand drug-drug interactions leading to thromboembolic outcomes or death.

Society of Family Planning clinical recommendations: Management of individuals with bleeding or thrombotic disorders undergoing abortion

Individuals who have bleeding disorders, thrombophilias, a history of venous thromboembolism (VTE), or who are taking anticoagulation medication for other reasons may present for abortion. Clinicians should be aware of risk factors and histories concerning for excessive bleeding and thrombotic disorders around the time of abortion. This document will focus on how to approach abortion planning in these individuals. For first-trimester abortion, procedural abortion (sometimes called surgical abortion) is generally preferred over medical management for individuals with bleeding disorders or who are on anticoagulation. First-trimester procedural abortion in an individual on anticoagulation can generally be done without interruption of anticoagulation. The decision to interrupt anticoagulation for a second-trimester procedure should be individualized. Individuals at high risk for VTE can be offered anticoagulation post-procedure. Individuals with bleeding disorders or who are anticoagulated can safely be offered progestin intrauterine devices. Future research is needed to better assess quantitative blood loss and complications rates with abortion in these populations.

The outcomes of three-factor prothrombin complex concentrate (3F-PCC) in warfarin anticoagulation reversal: a prospective, single-arm, open-label, multicentre study

There is a wide variation on the efficacy of three-factor Prothrombin Complex Concentrate (3F-PCC) in warfarin reversal. We aimed to determine the efficacy and safety of 3F-PCC in warfarin reversal. This multicentre prospective study analysed data from adult patients on warfarin who received 3F-PCC (Prothrombinex-VF®) for anticoagulation reversal between June 2019 to October 2020. Purposive sampling was used in this study. Study endpoints included target INR achievement, adverse drug reactions (ADRs), and in-hospital all-cause mortality. Logistic regression analyses were used to assess independent predictors of study endpoints. One-hundred thirty-seven patients with a median age of 68 (59-76) years were recruited, who were predominantly male (59.9%, n = 82). A total of 102 patients required 3F-PCC for life-threatening (40.9%, n = 56) and clinically significant bleeding (33.6%, n = 46). Initial INRs ranged from 1.55 to undetectable high (> 26). All patients had INR reduction, of which 62% (n = 85) achieved target INR, whereas 12.4% (n = 17) achieved INR below the target range. Median INR was reduced from 4.76 (3.14-8.32) to 1.54 (1.27-1.88) post-3F-PCC (p < 0.001). The use of adjunctive reversal agents and initial INR < 3.6 were the significant predictors for target INR achievement. Six (4.4%) ADRs were observed. Two (1.5%) cases with the suspected acute coronary syndrome were associated with mortality. Ischemic stroke occurred in one (0.7%) patient. The incidence of in-hospital all-cause mortality was 21.2% (n = 29). The rate of INR achievement was 62% in our study without apparent increased risk of thromboembolic events and in-hospital all-cause mortality.

Prophylactic placement of inferior vena cava filters and the risk of death or venous thromboembolism in severe trauma patients: a retrospective study comparing two hospitals with different approaches

Background

Prophylactic use of inferior vena cava filters to prevent pulmonary embolism in trauma is controversial. The practice varies between hospitals and countries, in part due to conflicting evidence and guidelines.

Purpose

To compare the effects of pulmonary embolism, deep venous thrombosis and mortality in two hospitals using prophylactic inferior vena cava filter placement or prophylactic anticoagulation alone.

Material and Methods

Patients presenting with severe trauma were recruited from two level-1 trauma centres between January 2008 and December 2013. Recruited patients from an US hospital having prophylactic inferior vena cava filter inserted were compared to a Scandinavian hospital using prophylactic anticoagulation alone. Inclusion criteria were age >15 years, Injury Severity Score >15 and survival >24 h after hospital admission. Patients with venous thromboembolism diagnosed prior to inferior vena cava filter placement were excluded. A Cox proportional hazard regression model was used with adjustment for immortal time bias and predictor variables.

Results

In total, 951 patients were reviewed, 282 from an US hospital having inferior vena cava filters placed and 669 from a Scandinavian hospital without inferior vena cava filters. The mean age was 45.9 vs. 47.4 years and the mean Injury Severity Score was 29.8 vs. 25.9, respectively. Inferior vena cava filter placement was not associated with the hazard of pulmonary embolism (Hazard ratio=0.43; 95% confidence interval (CI) 0.12, 1.45; P=0.17) or mortality (Hazard ratio=1.16; 95% CI 0.70, 1.95; P=0.56). However, an increased rate of deep venous thrombosis was observed with inferior vena cava filters in place (Hazard ratio=3.75; 95% CI 1.68, 8.36; P=0.001).

Conclusion

In severely injured trauma patients, prophylactic inferior vena cava filter placement was not associated with pulmonary embolism or mortality. However, inferior vena cava filters were associated with increased rate of deep venous thrombosis.

Updates on Anticoagulation and Laboratory Tools for Therapy Monitoring of Heparin, Vitamin K Antagonists and Direct Oral Anticoagulants

Anticoagulant drugs have been used to prevent and treat thrombosis. However, they are associated with risk of hemorrhage. Therefore, prior to their clinical use, it is important to assess the risk of bleeding and thrombosis. In case of older anticoagulant drugs like heparin and warfarin, dose adjustment is required owing to narrow therapeutic ranges. The established monitoring methods for heparin and warfarin are activated partial thromboplastin time (APTT)/anti-Xa assay and prothrombin time – international normalized ratio (PT-INR), respectively. Since 2008, new generation anticoagulant drugs, called direct oral anticoagulants (DOACs), have been widely prescribed to prevent and treat several thromboembolic diseases. Although the use of DOACs without routine monitoring and frequent dose adjustment has been shown to be safe and effective, there may be clinical circumstances in specific patients when measurement of the anticoagulant effects of DOACs is required. Recently, anticoagulation therapy has received attention when treating patients with coronavirus disease 2019 (COVID-19). In this review, we discuss the mechanisms of anticoagulant drugs—heparin, warfarin, and DOACs and describe the methods used for the measurement of their effects. In addition, we discuss the latest findings on thrombosis mechanism in patients with COVID-19 with respect to biological chemistry.

Management of warfarin-associated intracerebral hemorrhage before and after implementation of an order set and prospective pharmacist order verification

Management of warfarin-associated intracerebral hemorrhage (ICH) necessitates rapid reversal of anticoagulation. Guideline-based management of warfarin-associated ICH includes timely administration of prothrombin complex concentrate (PCC) and intravenous (IV) vitamin K. In 2017, our hospital implemented an order set for warfarin reversal to facilitate computerized provider order entry (CPOE), and the pharmacy department began prospective verification and dispensing of all PCC orders for anticoagulant reversal. We sought to compare the proportion of patients who received timely, guideline-based therapy for warfarin-associated ICH before and after these changes. We conducted a single-center, retrospective cohort study of all warfarin-associated ICH patients who had an order for PCC. A total of 66 patients were included; 32 patients (pre-intervention cohort) were evaluated in the 2 year period prior to the process improvement changes, while 34 patients (post-intervention cohort) were evaluated in the 2 year period following these changes. Baseline characteristics were similar between groups. The proportion of patients receiving timely guideline-based therapy was significantly higher in the post-intervention cohort compared to the pre-intervention cohort (76.5% vs 34.4%, p < 0.001), primarily driven by increased ordering of vitamin K 10 mg IV in conjunction with PCC in the post-intervention cohort. Our results indicate that implementation of an order set to assist with CPOE, in addition to prospective pharmacist verification of PCC orders, leads to increased adherence to guideline-based management of warfarin-associated ICH.

Endoscopic diagnosis and management of nonvariceal upper gastrointestinal hemorrhage (NVUGIH): European Society of Gastrointestinal Endoscopy (ESGE) Guideline - Update 2021

1: ESGE recommends in patients with acute upper gastrointestinal hemorrhage (UGIH) the use of the Glasgow-Blatchford Score (GBS) for pre-endoscopy risk stratification. Patients with GBS ≤ 1 are at very low risk of rebleeding, mortality within 30 days, or needing hospital-based intervention and can be safely managed as outpatients with outpatient endoscopy.Strong recommendation, moderate quality evidence. 2: ESGE recommends that in patients with acute UGIH who are taking low-dose aspirin as monotherapy for secondary cardiovascular prophylaxis, aspirin should not be interrupted. If for any reason it is interrupted, aspirin should be re-started as soon as possible, preferably within 3-5 days.Strong recommendation, moderate quality evidence. 3: ESGE recommends that following hemodynamic resuscitation, early (≤ 24 hours) upper gastrointestinal (GI) endoscopy should be performed. Strong recommendation, high quality evidence. 4: ESGE does not recommend urgent (≤ 12 hours) upper GI endoscopy since as compared to early endoscopy, patient outcomes are not improved. Strong recommendation, high quality evidence. 5: ESGE recommends for patients with actively bleeding ulcers (FIa, FIb), combination therapy using epinephrine injection plus a second hemostasis modality (contact thermal or mechanical therapy). Strong recommendation, high quality evidence. 6: ESGE recommends for patients with an ulcer with a nonbleeding visible vessel (FIIa), contact or noncontact thermal therapy, mechanical therapy, or injection of a sclerosing agent, each as monotherapy or in combination with epinephrine injection. Strong recommendation, high quality evidence. 7 : ESGE suggests that in patients with persistent bleeding refractory to standard hemostasis modalities, the use of a topical hemostatic spray/powder or cap-mounted clip should be considered. Weak recommendation, low quality evidence. 8: ESGE recommends that for patients with clinical evidence of recurrent peptic ulcer hemorrhage, use of a cap-mounted clip should be considered. In the case of failure of this second attempt at endoscopic hemostasis, transcatheter angiographic embolization (TAE) should be considered. Surgery is indicated when TAE is not locally available or after failed TAE. Strong recommendation, moderate quality evidence. 9: ESGE recommends high dose proton pump inhibitor (PPI) therapy for patients who receive endoscopic hemostasis and for patients with FIIb ulcer stigmata (adherent clot) not treated endoscopically. (A): PPI therapy should be administered as an intravenous bolus followed by continuous infusion (e. g., 80 mg then 8 mg/hour) for 72 hours post endoscopy. (B): High dose PPI therapies given as intravenous bolus dosing (twice-daily) or in oral formulation (twice-daily) can be considered as alternative regimens.Strong recommendation, high quality evidence. 10: ESGE recommends that in patients who require ongoing anticoagulation therapy following acute NVUGIH (e. g., peptic ulcer hemorrhage), anticoagulation should be resumed as soon as the bleeding has been controlled, preferably within or soon after 7 days of the bleeding event, based on thromboembolic risk. The rapid onset of action of direct oral anticoagulants (DOACS), as compared to vitamin K antagonists (VKAs), must be considered in this context.Strong recommendation, low quality evidence.

Risk factors for postdischarge venous thromboembolism among bariatric surgery patients and the evolving approach to extended thromboprophylaxis with enoxaparin

BACKGROUND

Venous thromboembolism (VTE) is one of the most common causes of postoperative mortality following bariatric surgery. The majority of VTE events occur after discharge from the hospital. Little consensus exists regarding who should receive extended enoxaparin thromboprophylaxis or how they should be dosed, namely whether to use weight-based or BMI-stratified dosing strategies.

OBJECTIVES

Provide an overview of the risk factors associated with VTE in procedures among bariatric patients including the use of predictive tools to stratify risk and the various approaches to enoxaparin chemoprophylaxis in obesity.

SETTING

Multiple centers.

METHODS

A review of the literature identified studies evaluating risk factors for VTE including demographic characteristics, co-morbidities, and operative factors. The use of calculators to stratify patients by risk and approaches to extended thromboprophylaxis in obesity were evaluated as well.

RESULTS

VTE was associated with increased age, weight, male sex, and prior history of VTE, all frequently included in risk calculators. Outside of those major risk factors, there is little consensus about the importance of patient diagnoses. Weight-based dosing was often superior to standardized dosing in studies across disciplines in generating target anti-Xa levels however there is no consistent association of reduced risk of VTE with therapeutic anti-Xa levels.

CONCLUSIONS

Risk calculators may be a valuable tool for identifying patients at high-risk for VTE, but their efficacy depends on the rating algorithm and inclusion of various risk factors and is methodologically limited by prophylactic interventions. Future work should consider if biochemical factors should be included in patient stratification approaches in particular when defining the ideal chemoprophylaxis approach. Transparency and consistency in data collection and reporting is needed to better assess and inform the ideal dosing strategy to prevent VTE following bariatric surgery.

Severe Acute Thromboinflammation: Case Report of Individualized Homeopathic Treatment

Thromboinflammation is a still not well-understood phenomenon, which has recently come to the foreground as a function of its relevance in the pathophysiology of coronavirus disease 2019 (COVID-19). The patient described in the present case report exhibited acute fever, giant urticaria, elevated acute phase reactants, and very high d-dimer levels, thus characterizing thromboinflammation. She was diagnosed as a COVID-19 suspect case, which was not confirmed; urticarial vasculitis was ruled out. Homeopathic treatment was started with the earliest clinical manifestations, resulting in rapid and drastic reduction of inflammation and hypercoagulability within the first 12 hours, and full recovery on 10-day follow-up assessment. This case demonstrates the effectiveness of homeopathy in a severe acute disorder, and points to the need to include laboratory testing in homeopathic clinical assessment to achieve an accurate picture of disease, and to avoid the risk of passing over life-threatening disorders.

Gut Microbiota and the Quality of Oral Anticoagulation in Vitamin K Antagonists Users: A Review of Potential Implications

The efficacy and safety of vitamin K antagonists (VKAs) as oral anticoagulants (OACs) depend on the quality of anticoagulation control, as reflected by the mean time in therapeutic range (TTR). Several factors may be involved in poor TTR such as comorbidities, high inter-individual variability, interacting drugs, and non-adherence. Recent studies suggest that gut microbiota (GM) plays an important role in the pathogenesis of cardiovascular diseases, but the effect of the GM on anticoagulation control with VKAs is unknown. In the present review article, we propose different mechanisms by which the GM could have an impact on the quality of anticoagulation control in patients taking VKA therapy. We suggest that the potential effects of GM may be mediated first, by an indirect effect of metabolites produced by GM in the availability of VKAs drugs; second, by an effect of vitamin K-producing bacteria; and finally, by the structural modification of the molecules of VKAs. Future research will help confirm these hypotheses and may suggest profiles of bacterial signatures or microbial metabolites, to be used as biomarkers to predict the quality of anticoagulation. This could lead to the design of intervention strategies modulating gut microbiota, for example, by using probiotics.

INR Response to Low-Dose Vitamin K in Warfarin Patients

BACKGROUND

Literature suggests that 2 mg of vitamin K intravenously (IV) provides a similar effect as 10 mg to reverse warfarin. Doses <5 mg haven't been studied in depth.

OBJECTIVE

The objective was to determine the international normalized ratio (INR) reduction effect of ultra low-dose (ULD) IV vitamin K.

METHODS

This retrospective, observational cohort study compared IV vitamin K doses of 0.25-0.5 mg (ULD) versus 1-2 mg (standard low dose [SLD]). The primary outcome assessed ΔINR at 36 hours; secondary outcomes assessed ΔINR at 12 hours and 30-day venous thromboembolism (VTE) and mortality rates.

RESULTS

Of 88 patients identified (median baseline INR [IQR], 5.1 [3.1, 7.3] vs 4.5 [2.8, 8.2], ULD vs SLD, respectively), 59 had an INR at 12 hours. The ULD had fewer 12-hour INR values <2, with no statistical difference in the ΔINR at 12 hours between the ULD and SLD cohorts (median ΔINR, 2.2 [1.1, 3.4] vs 2.2 [1.1, 6.3]; P = 0.54; median INR, 2.3 vs 1.8). A total of 41 patients had both a 12- and 36-hour INR. No significant difference in the ΔINR between the 12- and 36-hour values occurred (median ΔINR, 0.52 [0.2, 0.91] vs ΔINR, 0.46 [0.18, 0.55]; P = 0.61), suggesting no rebound or excessive reversal and no difference in 30-day rates of VTE (P > 0.99) or death (P = 0.38).

CONCLUSION AND RELEVANCE

ULD IV vitamin K reversed INR similarly to doses of 1-2 mg without rebound. A ULD strategy may be considered in patients requiring more cautious reversal.

An ensemble learning based framework to estimate warfarin maintenance dose with cross-over variables exploration on incomplete data set

MOTIVATION

Warfarin is a widely used oral anticoagulant, but it is challenging to select the optimal maintenance dose due to its narrow therapeutic window and complex individual factor relationships. In recent years, machine learning techniques have been widely applied for warfarin dose prediction. However, the model performance always meets the upper limit due to the ignoration of exploring the variable interactions sufficiently. More importantly, there is no efficient way to resolve missing values when predicting the optimal warfarin maintenance dose.

METHODS

Using an observational cohort from the Xinhua Hospital affiliated to Shanghai Jiaotong University School of Medicine, we propose a novel method for warfarin maintenance dose prediction, which is capable of assessing variable interactions and dealing with missing values naturally. Specifically, we examine single variables by univariate analysis initially, and only statistically significant variables are included. We then propose a novel feature engineering method on them to generate the cross-over variables automatically. Their impacts are evaluated by stepwise regression, and only the significant ones are selected. Lastly, we implement an ensemble learning based approach, LightGBM, to learn from incomplete data directly on the selected single and cross-over variables for dosing prediction.

RESULTS

377 unique patients with eligible and time-independent 1173 warfarin order events are included in this study. Through the comprehensive experimental results in 5-fold cross-validation, our proposed method demonstrates the efficiency of exploring the variable interactions and modeling on incomplete data. The R² can achieve 75.0% on average. Moreover, the subgroup analysis results reveal that our method performs much better than other baseline methods, especially in the medium-dose and high-dose subgroups. Lastly, the IWPC dosing prediction model is used for further comparison, and our approach outperforms it by a significant margin.

CONCLUSION

In summary, our proposed method is capable of exploring the variable interactions and learning from incomplete data directly for warfarin maintenance dose prediction, which has a great premise and is worthy of further research.

Evaluation of a Fixed-Dose Regimen of 4-Factor Prothrombin Complex Concentrate for Warfarin Reversal

BACKGROUND

Fixed-dose (FD) regimens of 4-factor prothrombin complex concentrate (4F-PCC) may be effective for the emergent reversal of warfarin; however, the optimal dosing is unknown. Our institution transitioned to a FD regimen of 1000 or 2000 units of 4F-PCC based on indication.

OBJECTIVE

The purpose of this study is to report our experience with FD 4F-PCC compared with a historical weight-based dosing cohort for warfarin reversal.

METHODS

A retrospective analysis was conducted for 3 groups: central nervous system (CNS) bleeds regardless of international normalized ratio (INR), non-CNS bleeds with an initial INR ≤6, and non-CNS bleeds with an initial INR ≥6.1. The primary outcome of the study was achievement of the target INR.

RESULTS

There were 54 patients with a CNS bleed, 153 with a non-CNS bleed and INR ≤6, and 19 with a non-CNS bleed and INR ≥6.1. In the CNS bleeding group, weight-based and FD achieved target INR 79.4% and 70% (P = 0.52). In the INR ≥6.1 non-CNS bleeding group, weight-based and FD achieved target INR 100% and 70% (P = 0.21). In the INR ≤6 non-CNS bleeding group, weight-based and FD achieved target INR 86.4% and 57.5% (P = 0.0002).

CONCLUSION AND RELEVANCE

An FD strategy of 2000 units for warfarin reversal for CNS bleeds or INR ≥6.1 was comparable to weight-based dosing. The FD strategy of 1000 units for INR ≤6 achieved target INR less often than weight-based dosing. Application of findings suggest that higher doses may be needed to achieve target INR.

Resuming Anticoagulation Following Hospitalization for Gastrointestinal Bleeding Is Associated with Reduced Thromboembolic Events and Improved Mortality: Results from a Systematic Review and Meta-Analysis

BACKGROUND

Systemic anticoagulants are widely prescribed for prevention and treatment of thromboembolism, but are commonly complicated by gastrointestinal bleeding (GIB). Limited data exist on the management of anticoagulation after hospitalization for GIB and the subsequent risks of recurrent GIB, thromboembolism, and mortality.

METHODS

We performed a systematic review and meta-analysis of studies to determine risk of recurrent GIB, thromboembolism, and mortality after resuming anticoagulation following GIB. PubMed, EMBASE, and Scopus were searched for randomized controlled trials and cohort studies in patients with atrial fibrillation, venous thromboembolism, or valvular heart disease who received long-term warfarin or direct oral anticoagulants before experiencing GIB. Studies were included if data were available on anticoagulation management and outcomes of recurrent GIB, thromboembolism, and mortality following GIB.

RESULTS

A total of 5354 studies were reviewed of which 10 were included in the meta-analysis. There were 2080 patients who resumed anticoagulation and 2296 patients who discontinued anticoagulation post-index GIB. Resumption of anticoagulation was associated with a significant increase in recurrent GIB (OR 1.646, 95% CI 1.035-2.617, p = 0.035). There was a significant decrease in thromboembolic events in patients who resumed anticoagulation compared to those who did not (OR 0.340, 95% CI 0.178-0.652, p = 0.001, I² = 62.7%). Resumption of anticoagulation was associated with a significant reduction in all-cause mortality (OR 0.499, 95% CI 0.419-0.595, p < 0.0001).

CONCLUSION

While resumption of anticoagulation following index GIB was associated with a significant increase in recurrent GIB, it was also associated with a significant decrease in thromboembolic events and all-cause mortality.

Thrombotic antiphospholipid syndrome: A practical guide to diagnosis and management

Thrombotic antiphospholipid syndrome (APS) is characterised by venous, arterial and/or small vessel thrombosis in the context of persistently positive antiphospholipid antibodies (aPL). The diagnosis and management of thrombotic APS continues to prove challenging for clinicians. We provide a practical guide to the diagnosis of APS including who to test for aPL and which tests to do. We also consider clinical practice points on the management of venous, arterial and small vessel thrombosis, in the context of first and recurrent thrombotic events. Non-criteria manifestations of APS are reviewed. An approach to recurrent thrombosis and anticoagulant-refractory APS is discussed, with options including increasing the anticoagulation intensity of vitamin K antagonists, switching to low-molecular-weight-heparin, the use of fondaparinux and/or the addition of antiplatelet treatment. Adjunctive options such as vitamin D, hydroxychloroquine and statins are also addressed.

Thrombotic antiphospholipid syndrome: A practical guide to diagnosis and management

Thrombotic antiphospholipid syndrome (APS) is characterised by venous, arterial and/or small vessel thrombosis in the context of persistently positive antiphospholipid antibodies (aPL). The diagnosis and management of thrombotic APS continues to prove challenging for clinicians. We provide a practical guide to the diagnosis of APS including who to test for aPL and which tests to do. We also consider clinical practice points on the management of venous, arterial and small vessel thrombosis, in the context of first and recurrent thrombotic events. Non-criteria manifestations of APS are reviewed. An approach to recurrent thrombosis and anticoagulant-refractory APS is discussed, with options including increasing the anticoagulation intensity of vitamin K antagonists, switching to low-molecular-weight-heparin, the use of fondaparinux and/or the addition of antiplatelet treatment. Adjunctive options such as vitamin D, hydroxychloroquine and statins are also addressed.

Cost saving analysis of specialized, eHealth-based management of patients receiving oral anticoagulation therapy: Results from the thrombEVAL study

To evaluate the cost-saving of a specialized, eHealth-based management service (CS) in comparison to regular medical care (RMC) for the management of patients receiving oral anticoagulation (OAC) therapy. Costs of hospitalization were derived via diagnosis-related groups which comprise diagnoses (ICD-10) and operation and procedure classification system (OPS), which resulted in OAC-related (i.e. bleeding/ thromboembolic events) and non-OAC-related costs for both cohorts. Cost for anticoagulation management comprised INR-testing, personnel, and technical support. In total, 705 patients were managed by CS and 1490 patients received RMC. The number of hospital stays was significantly lower in the CS cohort compared to RMC (CS: 23.4/100 py; RMC: 68.7/100 py); with the most pronounced difference in OAC-related admissions (CS: 2.8/100 py; RMC: 13.3/100 py). Total costs for anticoagulation management amounted to 101 EUR/py in RMC and 311 EUR/py in CS, whereas hospitalization costs were 3261 [IQR 2857-3689] EUR/py in RMC and 683 [504-874] EUR/py in CS. This resulted in an overall cost saving 2368 EUR/py favoring the CS. The lower frequency of adverse events in anticoagulated patients managed by the telemedicine-based CS compared to RMC translated into a substantial cost-saving, despite higher costs for the specialized management of patients.Trial registration: ClinicalTrials.gov, unique identifier NCT01809015, March 8, 2013.

Review of Medical Therapies for the Management of Pulmonary Embolism

Traditionally, the management of patients with pulmonary embolism has been accomplished with anticoagulant treatment with parenteral heparins and oral vitamin K antagonists. Although the administration of heparins and oral vitamin K antagonists still plays a role in pulmonary embolism management, the use of these therapies are limited due to other options now available. This is due to their toxicity profile, clearance limitations, and many interactions with other medications and nutrients. The emergence of direct oral anticoagulation therapies has led to more options now being available to manage pulmonary embolism in inpatient and outpatient settings conveniently. These oral therapeutic options have opened up opportunities for safe and effective pulmonary embolism management, as more evidence and research is now available about reversal agents and monitoring parameters. The evolution of the pharmacological management of pulmonary embolism has provided us with better understanding regarding the selection of anticoagulants. There is also a better understanding and employment of anticoagulants in pulmonary embolism in special populations, such as patients with liver failure, renal failure, malignancy, and COVID-19.

Institution of prothrombin complex concentrate protocols is associated with a reduction in plasma administration at a Tertiary Care Hospital

STUDY OBJECTIVE

Explore how the introduction of 4-factor prothrombin complex concentrates (4F-PCC) protocols for reversing anticoagulation and the treatment of critical bleeding influenced blood product utilization.

DESIGN

A retrospective analysis of the utilization rate of plasma and 4F-PCC from September 2012 through December 2018.

SETTING

Blood bank and pharmacy records of a single large tertiary care medical center.

PATIENTS

Admitted patients except obstetric during the study period (n = 283,319).

INTERVENTION

Five institutional protocols providing guidelines for 4F-PCC administration were deployed over a 3-year period.

MEASUREMENTS

The utilization rate of plasma and 4F-PCC was the primary outcome and analyzed using an interrupted time series analysis. Utilization of platelets and cryoprecipitate as well as the impact of the intervention on the service prescribing the blood products were evaluated as secondary outcomes. Data were evaluated using a segmented time series regression.

RESULTS

When adjusted for seasonality, the monthly rate of plasma administration was 24.7 ± 2.0 units per 100 admissions in the 6-month period prior to the 1st intervention (May-October 2013) and decreased to 9.9 ± 2.2 units per 100 admissions in the same six-month period following the 5th intervention (May-October 2018), median difference - 14.5, 95% CI -16.0 to -13.2, P < 0.001. During the 6-month period prior to the 1st intervention (May-October 2013) the monthly rate of 4-F PCC use was 1.2 ± 0.8 doses per 1000 admissions and increased to 2.8 ± 1.0 doses per 1000 admissions 6-months following the 5th intervention (May-October 2018), median difference 1.6, 95% CI 0.3 to 1.9, P = 0.014. The monthly utilization of platelets was decreased and cryoprecipitate slightly increased following the implementation of the PCC protocols.

CONCLUSIONS AND RELEVANCE

Our findings demonstrate that establishing institutional protocols for the use of 4F-PCC to reverse the effects of anticoagulation and to treat critical bleeding with associated coagulopathy was associated with reduced plasma utilization.

Comparison of Surgical Site Infection Risk Between Warfarin, LMWH, and Aspirin for Venous Thromboprophylaxis in TKA or THA: A Systematic Review and Meta-Analysis

BACKGROUND

Infection following arthroplasty can have devastating effects for the patient and necessitate further surgery. Venous thromboembolism (VTE) prophylaxis is required to minimize the risk of deep venous thrombosis and pulmonary embolism. Anticoagulation has been demonstrated to interfere with wound-healing and increase the risk of infection. We hypothesized that different anticoagulation regimes will have differing effects on rates of periprosthetic joint infection. The aim of this study was to compare the surgical site infection risk between the use of warfarin, low-molecular-weight heparin (LMWH), and aspirin for VTE prophylaxis following total knee or hip arthroplasty.

METHODS

A systematic literature search was conducted in November 2018 using the PubMed, CINAHL, and Cochrane Central Register of Controlled Trials (CENTRAL) databases to identify studies that compared warfarin, LMWH, and/or aspirin with regard to surgical site infection rates following hip or knee arthroplasty. Meta-analyses were performed to compare the infection and VTE risks between groups.

RESULTS

Nine articles involving 184,037 patients met the inclusion criteria. Meta-analysis showed that warfarin prophylaxis was associated with a higher risk of deep infection (or infection requiring reoperation) (odds ratio [OR] = 1.929, 95% confidence interval [CI] = 1.197 to 3.109, p = 0.007) and surgical site infection overall (OR = 1.610, 95% CI = 1.028 to 2.522, p = 0.038) compared with aspirin in primary total joint arthroplasty, with similar findings also seen when primary and revision procedures were combined. There was no significant difference in infection risk between warfarin and LMWH and between LMWH and aspirin. There was a nonsignificant trend for VTE risk to be higher with warfarin compared with aspirin therapy for primary procedures (OR = 1.600, 95% CI = 0.875 to 2.926, p = 0.127), and this was significant when both primary and revision cases were included (OR = 2.674, 95% CI = 1.143 to 6.255, p = 0.023).

CONCLUSIONS

These findings caution against the use of warfarin for VTE prophylaxis for hip and knee arthroplasty. Further randomized head-to-head trials and mechanistic studies are warranted to determine how specific anticoagulants impact infection risk.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Comparison of 3 Different Prothrombin Complex Concentrate Regimens for Emergent Warfarin Reversal: PCCWaR Study

BACKGROUND

The ideal dose and specific prothrombin complex concentrate (PCC) for warfarin reversal is unknown.

OBJECTIVE

To evaluate the reduction in international normalized ratio (INR) of 3 different PCC dosing regimens: fixed-dose activated 4-factor PCC (aPCC), fixed-dose 4-factor PCC (4PCC), and standard-dose 4PCC.

METHODS

This was a multicenter retrospective cohort review. Patients >18 years of age who received PCC for warfarin reversal between January 1, 2017, and December 31, 2017, were screened for inclusion. Patients were excluded if they did not receive the correct PCC dosing regimen, received PCC for nonwarfarin bleeding, had a baseline INR less than 2, or received a massive transfusion protocol. Two institutions utilized aPCC dosed at 500 IU for INR <5 and 1000 IU for INR ≥5. Two institutions utilized fixed-dose 4PCC at 1500 to 2000 units depending on patient factors. Two institutions utilized 4PCC package insert dosing. The primary outcome was achievement of post-PCC target INR ≤1.4. Secondary outcomes included percentage change in INR, lowest 24-hour INR, and mortality.

RESULTS

A total of 154 patients were included (fixed-dose aPCC: n = 29; fixed-dose 4PCC: n = 53; standard-dose 4PCC: n = 72). There was no statistical difference between groups in achieving the primary outcome (58.6% vs 69.8% vs 79.2%, respectively; P = 0.103) or any secondary outcomes.

CONCLUSION AND RELEVANCE

There was no difference in the ability to achieve a post-PCC INR of ≤1.4 between 3 different PCC regimens for warfarin reversal. Additional research is warranted to determine the ideal dose and PCC agent for warfarin reversal.

Development of an Institutional Periprocedural Management Guideline for Oral Anticoagulants

Patients on oral anticoagulation commonly undergo surgery or other invasive procedures. Periprocedural management of oral anticoagulants involves a careful balance of the thromboembolic risk and bleeding risk. To standardize clinical practice at our institution, we developed a guideline for periprocedural management for patients taking oral anticoagulants that incorporates published data and expert opinion. In this article, we present our clinical practice guideline as a decision support tool to aid clinicians in developing a consistent strategy for managing periprocedural anticoagulation and for safely bridging anticoagulation in patients who require it.

The Future Directions of Research in Cardiac Anesthesiology

This article provides an overview of knowledge gaps that need to be addressed in cardiac anesthesia, including mitigating the inflammatory effects of cardiopulmonary bypass, defining myocardial infarction after cardiac surgery, improving perioperative neurologic outcomes, and the optimal management of patients undergoing valve replacement. In addition, emerging approaches to research conduct are discussed, including the use of new analytical techniques like machine learning, pragmatic trials, and adaptive designs.

Clinical Practice Guideline for the Management of Antithrombotic Agents in Patients Undergoing Gastrointestinal Endoscopy

Antithrombotic agents, including antiplatelet agents and anticoagulants, are increasingly used in South Korea. The management of patients using antithrombotic agents and requiring gastrointestinal endoscopy is an important clinical challenge. Although clinical practice guidelines (CPGs) for the management of patients receiving antithrombotic agents and undergoing gastrointestinal endoscopy have been developed in the Unites States, Europe, and Asia Pacific region, it is uncertain whether these guidelines can be adopted in South Korea. After reviewing current CPGs, we identified unmet needs and recognized significant discrepancies in the clinical practice among regions. This is the first CPG in Korea providing information that may assist endoscopists in the management of patients on antithrombotic agents who require diagnostic or elective therapeutic endoscopy. This guideline was developed through the adaptation process as an evidence-based method, with four guidelines retrieved by systematic review. Eligible guidelines were evaluated according to the Appraisal of Guidelines for Research and Evaluation II process, and 13 statements were established using a grading system. This guideline was reviewed by external experts before an official. It will be revised as necessary to cover changes in technology, evidence, or other aspects of clinical practice.