Targeting ferroptosis for treating kidney disease

Ferroptosis is a type of regulated cell death hallmarked by iron-mediated excessive lipid oxidation. Over the past decade since the coining of the term ferroptosis, advances in research have led to the identification of intracellular processes that regulate ferroptosis such as GSH-GPX4 pathway and FSP1-coenzyme Q10/vitamin K pathway. From a disease perspective, the involvement of ferroptosis in pathological conditions including kidney disease has attracted attention. In terms of renal pathophysiology, ferroptosis has been widely investigated for its involvement in ischemia-reperfusion injury, nephrotoxin-induced kidney damage and other renal diseases. Therefore, therapeutic interventions targeting ferroptosis are expected to become a new therapeutic approach for these diseases. However, when considering cell death as a therapeutic target, careful consideration must be given to (i) in which type of cells, (ii) which type of cell death mode, and (iii) in which stage or temporal window of the disease. In the next decade, elucidation of the true involvement of ferroptosis in kidney disease setting in human, and development of clinically applicable and effective therapeutic drugs that target ferroptosis are warranted.

Equivalent thrombotic risk with Warfarin, Dabigatran, or Enoxaparin after failure of initial direct oral anticoagulation (DOAC) therapy

BACKGROUND

The direct oral anticoagulants (DOACs) are now commonly regarded as first line anticoagulants in most cases of venous thromboembolism (VTE). However, the optimal choice of subsequent anticoagulant in instances of first line DOAC failure is unclear.

OBJECTIVES

To describe and compare outcomes with second line anticoagulants used after DOAC failure.

METHODS

Patients seen at an urban hospital system for an episode of acute VTE initially treated with either apixaban or rivaroxaban who experienced a subsequent recurrent thrombosis while on anticoagulation (1st recurrent thrombosis) were included.

RESULTS

In total, 166 patients after apixaban or rivaroxaban failure were included. Following DOAC failure (1st recurrent thrombosis), the subsequent anticoagulant was warfarin in 60 patients (36%), dabigatran in 42 patients (25%), and enoxaparin in 64 patients (39%). Enoxaparin was preferentially prescribed in patients with a malignancy-associated etiology for 1st recurrent thrombosis (p < 0.01). The median follow-up time in our cohort was 16 months. There was no difference in 2nd recurrent thrombosis-free survival (p = 0.72) or risk for major bleeding event (p = 0.30) among patients treated with dabigatran, warfarin, or enoxaparin.

CONCLUSIONS

In this retrospective analysis of patients failing first line DOAC therapy, rates of 2nd recurrent thrombosis and bleeding did not differ among subsequently chosen anticoagulants. Our study provides evidence that the optimal 2nd anticoagulant is not clear, and the choice of 2nd anticoagulant should continue to balance patient preference, cost, and provider experience.

Pharmacogenetic guided versus standard warfarin dosing for routine clinical care with its pharmacoeconomic impact: a randomized controlled clinical trial

BACKGROUND

Empirical use of pharmacogenetic test(PGT) is advocated for many drugs, and resource-rich setting hospitals are using the same commonly. The clinical translation of pharmacogenetic tests in terms of cost and clinical utility is yet to be examined in hospitals of low middle income countries (LMICs).

AIM

The present study assessed the clinical utility of PGT by comparing the pharmacogenetically(PGT) guided- versus standard of care(SOC)- warfarin therapy, including the health economics of the two warfarin therapies.

METHODS

An open-label, randomized, controlled clinical trial recruited warfarin-receiving patients in pharmacogenetically(PGT) guided- versus standard of care(SOC)- study arms. Pharmacogenetic analysis of CYP2C9*2(rs1799853), CYP2C9*3(rs1057910) and VKORC1(rs9923231) was performed for patients recruited to the PGT-guided arm. PT(Prothrombin Time)-INR(international normalized ratio) testing and dose titrations were allowed as per routine clinical practice. The primary endpoint was the percent time spent in the therapeutic INR range(TTR) during the 90-day observation period. Secondary endpoints were time to reach therapeutic INR(TRT), the proportion of adverse events, and economic comparison between two modes of therapy in a Markov model built for the commonest warfarin indication- atrial fibrillation.

RESULTS

The study enrolled 168 patients, 84 in each arm. Per-protocol analysis showed a significantly high median time spent in therapeutic INR in the genotype-guided arm(42.85%; CI 21.4-66.75) as compared to the SOC arm(8.8%; CI 0-27.2)(p < 0.00001). The TRT was less in the PG-guided warfarin dosing group than the standard-of-care dosing warfarin group (17.85 vs. 33.92 days) (p = 0.002). Bleeding and thromboembolic events were similar in the two study groups. Lifetime expenditure was ₹1,26,830 in the PGT arm compared to ₹1,17,907 in the SOC arm. The QALY gain did not differ in the two groups(3.9 vs. 3.65). Compared to SOC, the incremental cost-utility ratio was ₹35,962 per QALY gain with PGT test opting. In deterministic and probabilistic sensitivity analysis, the base case results were found to be insensitive to the variation in model parameters. In the cost-effectiveness-acceptability curve analysis, a 90% probability of cost-effectiveness was reached at a willingness-to-pay(WTP) of ₹ 71,630 well below one time GDP threshold of WTP used.

CONCLUSION

Clinical efficacy and the cost-effectiveness of the warfarin pharmacogenetic test suggest its routine use as a point of care investigation for patient care in LMICs.

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

BACKGROUND

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

CASE PRESENTATION

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

CONCLUSION

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

Evaluation of modified fixed dose four-factor prothrombin complex concentrate for warfarin reversal

Non-activated four-factor prothrombin complex concentrate (4 F-PCC) has emerged as the preferred reversal strategy for patients on warfarin with life-threatening bleeding. Current dosing recommendations for 4 F-PCC require pre-treatment international normalized ratio (INR) and bodyweight values, resulting in ordering and administration delays. Studies have shown that alternative dosing regimens are safe and efficacious. This retrospective, single-center, pre- and post-protocol analysis was conducted to assess the efficacy of a pharmacist driven modified fixed-dose 4 F-PCC regimen versus package insert weight- and INR-based dosing regimen for warfarin reversal. The primary outcome was achievement of INR less than two. Secondary outcomes included dose and cost of 4 F-PCC, a time analysis, incidence of concomitant vitamin K administration, and incidence of thrombosis within seven days of 4 F-PCC. There were 195 patients included in the analysis, with 74 in the pre-cohort and 121 in the post-cohort. Baseline characteristics were similar between cohorts with the most common indication for warfarin use being atrial fibrillation (48.6% versus 47.1%) and reversal being intracerebral hemorrhage (68.9% versus 43.0%). Achievement of the primary endpoint occurred in 92% versus 95% (p = 0.097) of patients. A statistically significant difference was seen between cohorts regarding median dose and cost of 4 F-PCC administered (p < 0.001). Eleven thromboembolic events occurred with three events in the pre-cohort and eight events in the post-cohort (p = 0.453). A fixed-dose of 1500IU of 4 F-PCC was effective in reversing INR to less than two in most patients regardless of reversal indication with minimal thrombotic risks.

Therapeutic drug monitoring of six contraindicated/co-administered drugs by simple and green RP-HPLC-PDA; application to spiked human plasma

Therapeutic drug monitoring is an important clinical testing of the drugs to monitor their concentrations in plasma in order to guarantee their optimal impact, and to avoid any side effects resulting from drug-drug interactions. A green reversed-phase high-performance liquid chromatographic method using a photodiode array detector (RP-HPLC-PDA) was developed for the simultaneous determination of three carbapenem antibiotics (Imipenem, ertapenem, and meropenem) with the co-formulated drug (cilastatin) and contraindicated drugs (probenecid and warfarin) in spiked human plasma. The separation was achieved at 25 °C using a gradient elution of a mixture of mobile phase A: methanol and mobile phase B: phosphate buffer (pH 3.0). The photodiode array detector was adjusted at 220 nm. Bioanalytical method validation was carried out as per the FDA guidelines, and the method showed good linearity ranges for the six drugs that included their Cmax levels along with low limits of quantification. Based on the results, the method was found to be accurate and precise; with high % recovery and good % RSD, respectively. The method was successfully applied to spiked human plasma, signifying a good potential to be implemented in future TDM studies of these drugs when co-administered together.

Management of Anticoagulant and Antiplatelet Agents in Acute Gastrointestinal Bleeding and Prevention of Gastrointestinal Bleeding

Managing gastrointestinal bleeding in patients using antithrombotic agents remains challenging in clinical practice. This review article provides a comprehensive and evidence-based approach to managing acute antithrombotic-related gastrointestinal bleeding, focusing on the triage of patients, appropriate resuscitation, and timely endoscopy. The latest clinical practice guidelines are highlighted to guide decisions concerning the use of reversal agents, temporary interruption, and resumption of antithrombotic drugs. Additionally, preventive measures are discussed to lower the risk of future bleeding and minimize complications among patients prescribed antithrombotic drugs.

Pregnancy outcomes in Chinese women with mechanical heart valves receiving warfarin treatment throughout pregnancy: 14-year experience

OBJECTIVE

The purpose was to evaluate pregnancy outcomes and risk factors associated with fetal complications in Chinese pregnant women with mechanical heart valves (MHVs) taking low-dose warfarin, aiming to fill in the research gap of this area.

METHODS

Between June 2010 and Aug 2023, 122 patients with MHVs who had 151 pregnancies and received warfarin throughout pregnancy were included. We compared them with 302 paired pregnancies without warfarin treatment. Binary logistic regression analyses were performed to explore risk predictors of fetal complications.

RESULTS

Pregnancy loss rate was 37.1 % in women taking warfarin, compared to only 4.6 % for those without warfarin exposure in pregnancy (RR = 8.00, 95 % CI: 4.61-13.90). In pregnant women with MHVs, there were 34 spontaneous abortions, 22 stillbirths and 1 neonatal malformation. In the first, second and third pregnant trimesters of women with MHVs, fetal complication incidences were 19.2 %, 9.9 % and 8.0 %, respectively. 86.0 % of fetal complications occurred in women taking a warfarin dose ≤5 mg/d, accounting for 94.0 % of the total population. The newborns' birth weight, gestational age and 1-minute Apgar score were significantly lower in pregnancies treated with warfarin compared to those without warfarin exposure. Only 2.0 % of postpartum hemorrhage and no thrombosis or maternal mortality data were collected in pregnant women on warfarin in this study.

CONCLUSION

Most Chinese pregnant women take a warfarin daily dose ≤5 mg and they might have only around 60 % chance of giving birth to a live baby without maternal complications.

Characteristics and outcomes in elderly patients with non-valvular atrial fibrillation and high bleeding risk: subanalysis of the J-RHYTHM Registry

Recently, a once-daily dose of edoxaban (15-mg) has been approved for stroke prevention in non-valvular atrial fibrillation (NVAF) patients aged ≥ 80 years, in whom standard oral anticoagulants are not recommended because of high bleeding risk (HBR), based on the ELDERCARE-AF trial. However, information regarding the characteristics and clinical outcomes among such patients is limited. Thus, this study aimed to clarify the characteristics and event rates in elderly patients with NVAF and HBR defined by the ELDERCARE-AF criteria. Of the 7406 NVAF outpatients included in the J-RHYTHM Registry, 60 patients with creatinine clearance (CrCl) < 15 mL/min were excluded. The remaining 7346 patients (age, 69.7 ± 9.9 years; men, 70.9%; warfarin use, 78.7%) were divided into three groups: Group 1, aged < 80 years (n = 6165); Group 2, aged ≥ 80 years without HBR (n = 584); and Group 3, aged ≥ 80 years with HBR (at least one of the followings; CrCl, 15-30 mL/min, history of bleeding, body weight ≤ 45 kg, and antiplatelet use) (n = 597, eligible for 15-mg edoxaban). Patients in Group 3 had a higher prevalence of comorbidities, and therefore, both higher thromboembolic and bleeding risk scores than in the other groups. During the 2-year follow-up period, the incidence rates (per 100 person-years) of thromboembolism in Groups 1, 2, and 3 were 0.7, 1.5, and 2.1 (P < 0.001), major hemorrhage, 0.8, 1.2, and 2.0 (P < 0.001), and all-cause death, 0.8, 2.6, and 4.6 (P < 0.001), respectively. Adjusted hazard ratios of Group 3 were 1.64 (95% confidence interval 0.89-3.04, P = 0.116) for thromboembolism, 1.53 (0.85-2.72, P = 0.154) for major hemorrhage, and 1.84 (1.19-2.85, P = 0.006) for all-cause death compared with Group 1. The NVAF Patients aged ≥ 80 years with HBR defined by the ELDERCARE-AF criteria were certainly at a higher adverse event risk, especially for all-cause death. Clinical trial registration: The J-RHYTHM Registry is registered in the University Hospital Medicine Information Network (UMIN) Clinical Trials Registry (unique identifier: UMIN000001569) http://www.umin.ac.jp/ctr/ .

Association between gene polymorphisms and initial warfarin therapy in patients after heart valve surgery

BACKGROUND

Warfarin is widely used for the prevention and treatment of thrombotic events. This study aimed to examine the influence of gene polymorphisms on the early stage of warfarin therapy in patients following heart valve surgery.

METHODS

Nine single nucleotide polymorphisms were genotyped using microarray chips, categorizing patients into three groups: normal responders (Group I), sensitive responders (Group II), and highly sensitive responders (Group III). The primary clinical outcomes examined were time in therapeutic range (TTR) and international normalized ratio (INR) variability. To investigate potential influencing factors, a generalized linear regression model was employed.

RESULTS

Among 734 patients, the prevalence of CYP2C9*3-1075A > C, CYP2C19*3-636G > A, and CYP2C19*17-806C > T variants were 11.2%, 9.9%, and 1.9% of patients, respectively. VKORC1-1639G > A or the linked -1173C > T variant was observed in 99.0% of the patients. Generalized linear model analysis revealed an impact of sensitivity grouping on INR variability. Compared to Group I, Group II showed higher TTR values (p = 0.023), while INR variability was poorer in Group II (p < 0.001) and Group III (p < 0.001). Individual gene analysis identified significant associations between CYP2C9*3-1075A > C (p < 0.001), VKORC1-1639G > A or the linked -1173 C > T (p = 0.009) and GGCX-3261G > A (p = 0.019) with INR variability.

CONCLUSION

The genotypes of CYP2C9, VKORC1, and GGCX were found to have a significant impact on INR variability during the initial phase of warfarin therapy. However, no significant association was observed between TTR and gene polymorphisms. These findings suggest that focusing on INR variability is crucial in clinical practice, and preoperative detection of gene polymorphisms should be considered to assist in the initiation of warfarin therapy.

Clinical outcomes and anticoagulation therapy in elderly non-valvular atrial fibrillation and heart failure patients

AIMS

Atrial fibrillation (AF) and heart failure (HF) often coexist. Older age is strongly associated with stroke, HF, and mortality. The association between coexistence of HF and a risk of clinical outcomes and the effectiveness of anticoagulation therapy including direct oral anticoagulants (DOACs) in elderly patients with AF and HF have not been investigated. We aimed to evaluate 2 years of outcomes and to elucidate the efficacy of DOACs or warfarin in elderly AF patients in the All Nippon AF In the Elderly (ANAFIE) Registry with and without a history of HF.

METHODS AND RESULTS

The ANAFIE Registry is a multicentre, prospective observational study following elderly non-valvular AF patients aged ≥75 years for 2 years. Hazard ratios (HRs) were calculated based on the presence or absence of an HF diagnosis and DOAC or warfarin use at enrolment. Among 32 275 eligible patients, 12 116 (37.5%) had been diagnosed with HF. Patients with HF had significantly higher rates of HF hospitalization or cardiovascular death (HR 1.94, P < 0.001), cardiovascular events (HR 1.59, P < 0.001), cardiovascular death (HR 1.49, P < 0.001), all-cause death (HR 1.32, P < 0.001), and net clinical outcome including stroke/systemic embolism, major bleeding, and all-cause death (HR 1.23, P < 0.001), compared with those without HF; however, HRs for stroke/systemic embolism (HR 0.96, P = 0.56) and major bleeding (HR 1.14, P = 0.13) were similar. DOAC use was associated with a low risk of stroke/systemic embolism (HR 0.86, P = 0.19 in HF; HR 0.79, P = 0.016 in non-HF; P for interaction = 0.56), major bleeding (HR 0.71, P = 0.008 in HF; HR 0.75, P = 0.016 in non-HF; P for interaction = 0.74), HF hospitalization or cardiovascular death (HR 0.81, P < 0.001 in HF; HR 0.78, P < 0.001 in non-HF; P for interaction = 0.26), cardiovascular events (HR 0.83, P < 0.001 in HF; HR 0.82, P = 0.001 in non-HF; P for interaction = 0.65), cardiovascular death (HR 0.84, P = 0.12 in HF; HR 0.75, P = 0.035 in non-HF; P for interaction = 0.18), all-cause death (HR 0.89, P = 0.082 in HF; HR 0.80, P = 0.001 in non-HF; P for interaction = 0.091), and net clinical outcome (HR 0.88, P = 0.019 in HF; HR 0.81, P < 0.001 in non-HF; P for interaction = 0.21) compared with warfarin, irrespective of the presence or absence of HF. Analysis using the propensity score matching method showed similar associations.

CONCLUSIONS

Non-valvular AF patients aged ≥75 years with a history of HF had higher risks of cardiovascular events and mortality. DOACs were favourable to warfarin regardless of the coexistence of HF. These results might encourage the use of DOACs in elderly patients with non-valvular AF with or without HF.

Evaluation of warfarin management in primary health care centers in Qatar: A retrospective cross-sectional analysis of the national dataset

BACKGROUND

Warfarin management is associated with severe complications, highlighting the critical need to evaluate the quality of its administration.

OBJECTIVES

To evaluate the quality of warfarin management for patients managed in primary healthcare centers by measuring the percentage of Time in Therapeutic Range (TTR) and the proportion of extreme out-of-range international normalized ratio (INR) values.

METHODS

This is a cross-sectional study. Data was extracted from a national dataset retrieved from the largest primary healthcare provider in Qatar. TTR was calculated using the traditional method. Inferential and descriptive analyses were performed as appropriate.

RESULTS

Four hundred ninety-four patients met the inclusion criteria. The mean (SD) TTR was 45.3 % (17.5). This was significantly lower than the recommended cutoff value (P<0.001). Extreme out-of-range INR accounted for 24.7 % of total INR readings.

CONCLUSIONS

The management of patients taking warfarin in Qatar is inadequate. More effective strategies are warranted to ensure safe and effective therapy.

COVID-19 vaccination affects short-term anti-coagulation levels in warfarin treatment

Vaccines against SARS-CoV-2 have been recommended across the world, yet no study has investigated whether COVID-19 vaccination influences short-term warfarin anti-coagulation levels. Patients on stable warfarin treatment who received anti-SARS-CoV-2 vaccination were prospectively enrolled and followed up for three months. INR values less than 10 days before vaccination (baseline), 3-5 days (short-term) and 6-14 days (medium-term) after vaccination were recorded as INR0, INR1, and INR2, respectively. The variations of INR values within individuals were compared, and the linear mixed effect model was used to evaluate the variations of INR values at different time points. Logistic regression analysis was performed to determine covariates related to INR variations after COVID-19 vaccination. Vaccination safety was also monitored. There was a significant difference in INR values between INR0 and INR1 (2.15 vs. 2.26, p = 0.003), yet no marked difference was found between INR0 and INR2. The linear mixed effect model also demonstrated that INR variation was significant in short-term but not in medium-term or long-term period after vaccination. Logistic regression analysis showed that no investigated covariates, including age, vaccine dose, genetic polymorphisms of VKORC1 and CYP2C9 etc., were associated with short-term INR variations. Two patients (2.11%) reported gingival hemorrhage in the short-term due to increased INR values. The overall safety of COVID-19 vaccines for patients on warfarin was satisfying. COVID-19 vaccines may significantly influence warfarin anticoagulation levels 3-5 days after vaccination. We recommend patients on warfarin to perform at least one INR monitoring within the first week after COVID-19 vaccination.

Assessment of Temporary Warfarin Reversal in Patients With Left Ventricular Assist Devices: the KVAD Study

BACKGROUND

Patients with left ventricular assist devices (LVADs) require interruption of warfarin for invasive procedures, but parenteral bridging is associated with many complications. Four-factor prothrombin complex concentrate (4F-PCC) can temporarily restore hemostasis in patients undergoing anticoagulation with warfarin.

OBJECTIVES

This pilot study evaluated the strategy of using variable-dose 4F-PCC to immediately and temporarily reverse warfarin before invasive procedures without holding warfarin in patients with LVADs. The duration of effect of 4F-PCC on factor levels and time to reestablish therapeutic anticoagulation post procedure were assessed.

METHODS

Adult patients with LVADs and planned invasive procedures were enrolled from a single center. Warfarin was continued uninterrupted. The 4F-PCC dose administered immediately pre-procedure was based on study protocol. International normalized ratio (INR)- and vitamin K-dependent factor levels were collected before and during the 48 hours after 4F-PCC administration. The use of parenteral bridging, International Society for Thrombosis and Haemostasis major and clinically relevant nonmajor bleeding (CRNMB) and thromboembolic events at 7 and 30 days were collected.

RESULTS

In 21 episodes of 4F-PCC reversal, median baseline INR was 2.7 (IQR 2.2-3.2). The median dosage of 4F-PCC administered was 1794 units (IQR 1536-2130). At 24 and 48 hours post 4F-PCC administration, median INRs were 1.8 (IQR 1.7-2.0) and 2.0 (IQR 1.9-2.4). Two patients required postoperative bridging. One patient experienced major bleeding within 72 hours, and 2 experienced CRNMB within 30 days. There were no thromboembolic events. Baseline and post 4F-PCC vitamin K-dependent factor levels corresponded with changes in INR values. The median time to achieve therapeutic INR post-procedure was 2.5 days (IQR, 1-4).

CONCLUSION

Administration of 4F-PCC for temporary reversal of warfarin for invasive procedures in patients with LVADs allowed for continued warfarin dosing with minimal use of post-intervention bridging, limited bleeding and no thromboembolic events.

Factor Xa Inhibitors versus warfarin in patients with morbid obesity and atrial fibrillation

PURPOSE

Factor Xa Inhibitors have emerged as a first-line agent in the management of non-valvular atrial fibrillation (NVAF), but there is a need for additional data surrounding their use in the morbidly obese population. The purpose of this study was to evaluate whether Factor Xa Inhibitors are as safe and effective as warfarin for the treatment of NVAF in individuals with a BMI ≥ 40 kg/m2 and/or weight ≥ 120 kg.

METHODS

This was a multi-center retrospective cohort study comparing the use of Factor Xa Inhibitors (apixaban and rivaroxaban) to warfarin for the management of NVAF in adult patients with a BMI ≥ 40 kg/m2 and/or weight ≥ 120 kg. The primary outcomes were stroke or systemic embolism and major bleeding within 12 months.

RESULTS

A total of 3,156 patients were included in the final analysis; 1,396 in the warfarin group and 1760 in the Factor Xa Inhibitor group. The mean weight and BMI of the overall cohort was 134.1 kg and 44.7 kg/m2, respectively. There was no difference in stroke or systemic embolism (OR 1.21, 95% CI 0.78-1.85) or major bleeding (OR 0.99, 95% CI 0.65 - 1.53) with Factor Xa Inhibitors compared to warfarin after controlling for covariates.

CONCLUSION

This analysis of real-world data suggests no difference in bleeding or thrombotic outcomes for severely obese patients with NVAF taking Factor Xa Inhibitors compared to warfarin. Overall, our study adds further data to support the use of Factor Xa Inhibitors as an alternative to warfarin in severely obese patients with NVAF.

Low recurrent thrombosis rates in single positive antiphospholipid syndrome regardless of type of anticoagulation

Thrombotic antiphospholipid syndrome (TAPS) is characterized by thrombosis and persistently positive tests for antiphospholipid antibodies or lupus anticoagulant (LAC). Triple-positive APS has the highest risk of recurrent thrombosis, but no studies have focused on recurrent thrombosis in patients with single-positive TAPS. We conducted a retrospective cohort study of patients with single-positive TAPS diagnosed at Lifespan Health System, Rhode Island, to determine the rates and risk factors for recurrent thrombosis. Between January 2001 and April 2022, 128 patients were assessed who had single-positive APS (LAC = 98, aCL = 21, aβ2GPI = 9) and who had been followed for a total of 1453.8 patient-years (median follow-up 3.04 years). The initial antithrombotic regimen was warfarin in 44 %, a direct oral anticoagulant (DOAC) in 34 %, enoxaparin in 2 %, and no antithrombotic therapy or antiplatelet therapy only in 20 %. Recurrent thrombosis occurred in 16 (12.5 %) with a recurrent thrombosis rate of 3.08 per 100 patient-years. Systemic lupus erythematosus was the only variable significantly associated with recurrent thrombosis in a model adjusted for age, sex, body mass index, and type of positive APS test. All 16 patients with recurrent thrombosis were initially treated with warfarin, and, at the time of recurrent thrombosis, 13 patients remained on warfarin and three were off anticoagulation. In conclusion, the recurrent thrombosis rate in single-positive APS is low, and not all patients with a single-positive test may need indefinite anticoagulation with warfarin. Larger prospective studies are required to confirm this finding and establish optimal anticoagulation regimens for low-risk TAPS.

The optimal antithrombotic strategy for post-stroke patients with atrial fibrillation and extracranial artery stenosis-a nationwide cohort study

BACKGROUND

In post-stroke atrial fibrillation (AF) patients who have indications for both oral anticoagulant (OAC) and antiplatelet agent (AP), e.g., those with carotid artery stenosis, there is debate over the best antithrombotic strategy. We aimed to compare the risks of ischemic stroke, composite of ischemic stroke/major bleeding and composite of ischemic stroke/intracranial hemorrhage (ICH) between different antithrombotic strategies.

METHODS

This study included post-stroke AF patients with and without extracranial artery stenosis (ECAS) (n = 6390 and 28,093, respectively) identified from the Taiwan National Health Insurance Research Database. Risks of clinical outcomes and net clinical benefit (NCB) with different antithrombotic strategies were compared to AP alone.

RESULTS

The risk of recurrent ischemic stroke was higher for patients with ECAS than those without (12.72%/yr versus 10.60/yr; adjusted hazard ratio [aHR] 1.104, 95% confidence interval [CI] 1.052-1.158, p < 0.001). For patients with ECAS, when compared to AP only, non-vitamin K antagonist oral anticoagulant (NOAC) monotherapy was associated with lower risks for ischaemic stroke (aHR 0.551, 95% CI 0.454-0.669), the composite of ischaemic stroke/major bleeding (aHR 0.626, 95% CI 0.529-0.741) and the composite of ischaemic stroke/ICH (aHR 0.577, 95% CI 0.478-0.697), with non-significant difference for major bleeding and ICH. When compared to AP only, warfarin monotherapy was associated with higher risks of major bleeding (aHR 1.521, 95% CI 1.231-1.880), ICH (aHR 2.045, 95% CI 1.329-3.148), and the composite of ischaemic stroke and major bleeding. With combination of AP plus warfarin, there was an increase in ischaemic stroke, major bleeding, and the composite outcomes, when compared to AP only. NOAC monotherapy was the only approach associated with a positive NCB, while all other options (warfarin, combination of AP-OAC) were associated with negative NCB.

CONCLUSIONS

For post-stroke AF patients with ECAS, NOAC monotherapy was associated with lower risks of adverse outcomes and a positive NCB. Combination of AP with NOAC or warfarin did not offer any benefit, but more bleeding especially with AP-warfarin combination therapy.

Relationship of Warfarin and Apixaban with Vascular Function in Patients with Atrial Fibrillation

INTRODUCTION

Atrial fibrillation (AF) is associated with endothelial damage/dysfunction. Herein, we tested the hypothesis that brachial artery flow-mediated dilation (FMD) is superior in AF patients taking apixaban compared to warfarin.

METHODS

AF patients on apixaban (n = 46; 67 [7] years; mean [standard deviation]; 15 women) and warfarin (n = 27; 73 [9] years (p < 0.01); 11 women) were recruited. Duplex Doppler ultrasound imaging was undertaken during baseline (2 min), cuff inflation (5 min), and following cuff deflation (3 min). FMD was defined as peak increase in brachial artery diameter following cuff deflation and analysed as percentage change in diameter, as a ratio of FMD, shear rate area under the curve (SRAUC; FMD-to-SRAUC), and using SRAUC as a covariate (FMDSR).

RESULTS

Baseline artery diameter (4.96 [1.14] vs. 4.89 [0.88] mm), peak diameter (5.12 [1.17] vs. 5.14 [0.93] mm), and FMDSR (3.89 [3.62] vs. 4.80 [3.60] %) were not different between warfarin and apixaban (p > 0.05; analysis of covariance with age, CHA2DS2-VASc, years since AF diagnosis, number of diabetics, alcohol drinkers, and units of alcohol consumed per week as covariates). Stepwise multiple regression identified independent association of fibrillation, hypertension, and increased age with FMD.

CONCLUSION

AF patients on warfarin and apixaban exhibit similar endothelium-dependent vasodilation. Increased blood pressure negatively impacts vasodilator capacity in AF patients.

Oral prednisolone and warfarin and risk of oesophageal cancer: A case-control study

BACKGROUND

A recent epidemiological study systematically screened 250 prescription medications for associations with oesophageal cancer risk, using Scottish data, and identified an increased risk with use of prednisolone and warfarin. We investigated whether oral prednisolone or warfarin use was associated with increased oesophageal cancer risk.

METHODS

A case-control study was conducted within the Clinical Practice Research Datalink. In the primary analysis oesophageal cancer cases were identified from linked cancer registry records. Up to 5 cancer-free controls were matched to each case (based upon sex, birth year, GP practice and year of GP registration). Prednisolone and warfarin medications were identified from prescribing records. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using conditional logistic regression after adjusting for covariates including demographics, comorbidities and medication use.

RESULTS

There were 4552 oesophageal cancer cases and 22,601 matched control participants. Overall, there was no evidence of an increased risk of oesophageal cancer with oral prednisolone use (unadjusted OR=1.16 95% CI 1.06, 1.27 and adjusted OR=0.99 95% CI 0.89, 1.11) or warfarin use (unadjusted OR=1.12 95% CI 0.99, 1.28 and adjusted OR=1.08 95% CI 0.92, 1.27).

CONCLUSIONS

In this large population-based study, oral prednisolone and warfarin were not associated with oesophageal cancer risk.

Are anticoagulant drugs ecotoxic for meiobenthic nematodes from Saudi Arabia? First data on taxon/functional diversity and computational evidences

Community-level effects of anticoagulants have little been studied in the laboratory. In the current study, the different effects of Warfarin and Tinzaparin, individually or in combination, on meiofauna were investigated for the first time using two concentrations (5 and 25 mg·l-1) of Warfarin (W1 and W2) and Tinzaparin (T1 and T2) for 30 days. The results obtained highlighted the highest tolerance of nematodes and amphipods toward the two anticoagulants tested. Moreover, nematode abundance and taxonomic diversity decreased directly after exposure to T2 and T2W1 because of the high mortality of diatom feeders and their replacement by non-selective deposit feeders (case of Tinzaparin) or omnivores-carnivores (case of Warfarin). The relative taxon/functional similarity between controls and mixtures T1W1 and T2W2 recommends that the toxicity of Tinzaparin can be attenuated by Warfarin. Finally, the computational study of Warfarin supports its potential ecotoxicity since it satisfactorily bound and interacted with GLD-3 and SDP macromolecules.

Direct oral anticoagulants over warfarin at discharge associated with improved survival and patency in infra-geniculate bypasses with prosthetic conduits

OBJECTIVE

There is no consensus on the optimal anticoagulant regimen following lower extremity bypass. Historically, warfarin has been utilized for prosthetic or compromised vein bypasses. Direct-acting oral anticoagulants (DOACs) are increasingly replacing warfarin in this context, but their efficacy in bypass preservation has not been well-studied. Recent studies have shown that DOACs may improve outcomes following bypasses; however, it is unclear if this is dependent upon type of bypass conduit. The goal of this study was to evaluate whether a difference exists between vein and prosthetic infra-geniculate bypasses outcomes based on the anticoagulant utilized on discharge, warfarin or DOAC.

METHODS

The Vascular Quality Initiative infra-inguinal bypass database was queried for all patients who underwent an infra-geniculate bypass and were anticoagulation-naive at baseline but were discharged on either warfarin or DOACs. A survival analysis was performed for patients up to 1 year to determine whether the choice of discharge anticoagulation was associated with differences between those with vein vs prosthetic conduits in overall survival, primary patency, risk of amputation, or risk of major adverse limb events (MALE). A multivariable Cox proportional hazards analysis was performed to control for differences in baseline demographic factors between the groups.

RESULTS

During the study period (2003-2020), 57,887 patients underwent infra-geniculate bypass. Of these, 3230 (5.5%) were anticoagulated on discharge. There was a similar distribution of anticoagulation between vein (n = 1659; 51.4%) and prosthetic conduits (n = 1571; 48.6%). Thirty-two percent were discharged on DOACs, and 68.0% were discharged on warfarin. For prosthetic conduits, being discharged on a DOAC was associated with improved outcomes on univariate and multivariable analyses revealing lower risk of overall mortality (hazard ratio [HR], 0.61; 95% confidence interval [CI], 0.41-0.93; P = .021), loss of primary patency (HR, 0.70; 95% CI, 0.55-0.89; P = .003), risk of amputation (HR, 0.71; 95% CI, 0.54-0.93; P = .013), and risk of MALE (HR, 0.80; 95% CI, 0.64-1.00; P = .048). Patients with a vein bypass had improved univariate outcomes for survival and primary patency; however, with multivariable analysis, there were no significant differences in outcomes between DOAC and warfarin.

CONCLUSIONS

Anticoagulation-naive patients who underwent an infra-geniculate prosthetic bypass had higher rates of overall survival, bypass patency, amputation-free survival, and freedom from MALE when discharged on a DOAC compared with warfarin. Those with vein bypasses had similar outcomes regardless of the choice of anticoagulation.

Utility of a pharmacist-managed Anticoagulation Program in patients with congenital heart disease

BACKGROUND

Warfarin remains the preferred anticoagulant for many patients with CHD. The complexity of management led our centre to shift from a nurse-physician-managed model with many providers to a pharmacist-managed model with a centralized anticoagulation team. We aim to describe the patient cohort managed by our Anticoagulation Program and evaluate the impact of implementation of this consistent, pharmacist-managed model on time in therapeutic range, an evidence-based marker for clinical outcomes.

METHODS

A single-centre retrospective cohort study was conducted to evaluate the impact of the transition to a pharmacist-managed model to improve anticoagulation management at a tertiary pediatric heart centre. The percent time in therapeutic range for a cohort managed by both models was compared using a paired t-test. Patient characteristics and time in therapeutic range of the program were also described.

RESULTS

After implementing the pharmacist-managed model, the time in therapeutic range for a cohort of 58 patients increased from 65.7 to 80.2% (p < .001), and our Anticoagulation Program consistently maintained this improvement from 2013 to 2022. The cohort of patients managed by the Anticoagulation Program in 2022 included 119 patients with a median age of 24 years (range 19 months-69 years) with the most common indication for warfarin being mechanical valve replacement (n = 81, 68%).

CONCLUSIONS

Through a practice change incorporating a collaborative, centralized, pharmacist-managed model, this cohort of CHD patients on warfarin had a fifteen percent increase in time in therapeutic range, which was sustained for nine years.

Developing a GC-EI-MS/MS method for quantifying warfarin and five hydroxylated metabolites generated by the Fenton reaction

Since the 1950s, Warfarin has been used globally as both a prescription drug and a rodenticide. Research has shown that warfarin and other rodenticides are present in the environment and food chain. However, emerging contaminants are subject to degradation by biotic and abiotic processes and advanced oxidation processes. In some cases, detecting the parent compound may not be possible due to the formation of structurally changed species. This approach aims to identify hydroxylated transformation products of warfarin in a laboratory setting, even after the parent compound has undergone degradation. Therefore, the Fenton reaction is utilized to insert hydroxylation into the parent compound, warfarin, by hydroxyl and hydroperoxyl radicals generated by Fe2+/Fe3+ redox reaction with hydrogen peroxide. Using multiple reaction monitoring, a GC-MS/MS method, incorporating isotopically labeled reference compounds, is used to quantify the expected derivatized species. The analytes are derivatized using trimethyl-3-trifluoromethyl phenyl ammonium hydroxide, and the derivatization yield of warfarin is determined by using isotopically labeled reference compounds. The method has a linear working range of 30 to 1800 ng/mL, with detection limits ranging from 18.7 to 67.0 ng/mL. The analytes are enriched using a C18-SPE step, and the recovery for each compound is calculated. The Fenton reaction generates all preselected hydroxylated transformation products of warfarin. The method successfully identifies that 4'-Me-O-WAR forms preferentially under the specified experimental conditions. By further optimizing the SPE clean-up procedures, this GC-MS-based method will be suitable for detecting transformation products in more complex matrices, such as environmental water samples. Overall, this study provides a better understanding of warfarin's degradation and offers a robust analytical tool for investigating its transformation products.

Warfarin-A natural anticoagulant: A review of research trends for precision medication

BACKGROUND

Warfarin is a widely prescribed anticoagulant in the clinic. It has a more considerable individual variability, and many factors affect its variability. Mathematical models can quantify the quantitative impact of these factors on individual variability.

PURPOSE

The aim is to comprehensively analyze the advanced warfarin dosing algorithm based on pharmacometrics and machine learning models of personalized warfarin dosage.

METHODS

A bibliometric analysis of the literature retrieved from PubMed and Scopus was performed using VOSviewer. The relevant literature that reported the precise dosage of warfarin calculation was retrieved from the database. The multiple linear regression (MLR) algorithm was excluded because a recent systematic review that mainly reviewed this algorithm has been reported. The following terms of quantitative systems pharmacology, mechanistic model, physiologically based pharmacokinetic model, artificial intelligence, machine learning, pharmacokinetic, pharmacodynamic, pharmacokinetics, pharmacodynamics, and warfarin were added as MeSH Terms or appearing in Title/Abstract into query box of PubMed, then humans and English as filter were added to retrieve the literature.

RESULTS

Bibliometric analysis revealed important co-occuring MeShH and index keywords. Further, the United States, China, and the United Kingdom were among the top countries contributing in this domain. Some studies have established personalized warfarin dosage models using pharmacometrics and machine learning-based algorithms. There were 54 related studies, including 14 pharmacometric models, 31 artificial intelligence models, and 9 model evaluations. Each model has its advantages and disadvantages. The pharmacometric model contains biological or pharmacological mechanisms in structure. The process of pharmacometric model development is very time- and labor-intensive. Machine learning is a purely data-driven approach; its parameters are more mathematical and have less biological interpretation. However, it is faster, more efficient, and less time-consuming. Most published models of machine learning algorithms were established based on cross-sectional data sourced from the database.

CONCLUSION

Future research on personalized warfarin medication should focus on combining the advantages of machine learning and pharmacometrics algorithms to establish a more robust warfarin dosage algorithm. Randomized controlled trials should be performed to evaluate the established algorithm of warfarin dosage. Moreover, a more user-friendly and accessible warfarin precision medicine platform should be developed.

Efficacy and Safety of Warfarin for the Treatment of Venous Thromboembolism - A Multicenter Prospective Observational Cohort Study in Japan (AKAFUJI Study)

BACKGROUND

A large-scale prospective study of the efficacy and safety of warfarin for the treatment of venous thromboembolism (VTE) has not been conducted in Japan. Therefore, we conducted a real-world prospective multicenter observational cohort study (AKAFUJI Study; UMIN000014132) to investigate the efficacy and safety of warfarin for VTE.Methods and Results: Between May 2014 and March 2017, 352 patients (mean [±SD] age 67.7±14.8 years; 57% female) with acute symptomatic/asymptomatic VTE were enrolled; 284 were treated with warfarin. The cumulative incidence of recurrent symptomatic VTE was higher in patients without warfarin than in those treated with warfarin (8.7 vs. 2.2 per 100 person-years, respectively; P=0.018). The cumulative incidence of bleeding complications was not significantly different between the 2 groups. The mean prothrombin time-international normalized ratio (PT-INR) during warfarin on-treatment was <1.5 in 180 patients, 1.5-2.5 in 97 patients, and >2.5 in 6 patients. The incidence of bleeding complications was significantly higher in patients with PT-INR >2.5, whereas the incidence of recurrent VTE was not significantly different between the 3 PT-INR groups. The cumulative incidence of recurrent VTE and bleeding complications did not differ significantly among those in whom VTE was provoked by a transient risk factor, was unprovoked, or was associated with cancer.

CONCLUSIONS

Warfarin therapy with an appropriate PT-INR according to Japanese guidelines is effective without increasing bleeding complications, regardless of patient characteristics.

Effects of sodium ferulate for injection on anticoagulation of warfarin in rats in vivo

BACKGROUND

Herb-drug interactions may result in increased adverse drug reactions or diminished drug efficacy, especially for drugs with a narrow therapeutic index such as warfarin. The current study investigates the effects of sodium ferulate for injection (SFI) on anticoagulation of warfarin from aspects of pharmacodynamics and pharmacokinetics in rats and predicts the risk of the combination use.

METHODS

Rats were randomly divided into different groups and administered single- or multiple-dose of warfarin (0.2 mg/kg) with or without SFI of low dose (8.93 mg/kg) or high dose (26.79 mg/kg). Prothrombin time (PT) and activated partial thromboplastin time (APTT) were detected by a blood coagulation analyzer, and international normalized ratio (INR) values were calculated. UPLC-MS/MS was conducted to measure concentrations of warfarin enantiomers and pharmacokinetic parameters were calculated by DAS2.0 software.

RESULTS

The single-dose study demonstrated that SFI alone had no effect on coagulation indices, but significantly decreased PT and INR values of warfarin when the two drugs were co-administered (P < 0.05 or P < 0.01), while APTT values unaffected (P > 0.05). Cmax and AUC of R/S-warfarin decreased but CL increased significantly in presence of SFI (P < 0.01). The multiple-dose study showed that PT, APTT, INR, and concentrations of R/S-warfarin decreased significantly when SFI was co-administered with warfarin (P < 0.01). Warfarin plasma protein binding rate was not significantly changed by SFI (P > 0.05).

CONCLUSIONS

The present study implied that SFI could accelerate warfarin metabolism and weaken its anticoagulation intensity in rats.

Treatment of acute pulmonary embolism after catheter-directed thrombolysis with dabigatran vs warfarin: results of a multicenter randomized RE-SPIRE trial

BACKGROUND

Thrombolytic therapy is effective method in the high-risk acute pulmonary embolism (PE) treatment. Reduced-dose thrombolysis (RDT) plus oral anticoagulation therapy is effective and safe method in the moderate and severe PE treatment. It is leading to good early and intermediate-term outcomes. In the RE-COVER and RE-COVER II studies, dabigatran showed similar effectiveness as warfarin in the treatment of acute PE. Dabigatran leads to fewer hemorrhagic complications and is not inferior in efficacy to warfarin in the prevention of PE after mechanical fragmentation and RDT (catheter-directed treatment [CDT]+RDT) in patients with high and intermediate to high PE risk. We sought to evaluate the efficacy and safety (incidence of clinically significant recurrence of venous thromboembolic complications and deaths) during a 6-month course of treatment with dabigatran or warfarin in patients with high and intermediate to high acute PE risk after endovascular mechanical thrombus fragmentation procedure with RDT (CDT+RDT).

METHODS

The RE-SPIRE is a prospective, multicenter randomized double-arm study. Over a 5-year period, 66 consecutive patients with symptomatic high and intermediate to high PE risk after endovascular mechanical thrombus fragmentation procedure with RDT (CDT+RDT) were randomized into two groups within the next 48 hours. The first group continued treatment with dabigatran 150 mg twice a day for 6 months; the second group continued treatment with warfarin under the control of international normalized ratio (2.0-3.0) for 6 months. Both groups received low molecular weight heparins for 2 days after surgery. Then, group 1 continued to receive low molecular-weight-heparin for 5 to 7 days, followed by a switch to dabigatran at a dosage of 150 mg two times a day. Group 2 received both low-molecular-weight heparin and warfarin up to an international normalized ratio of >2.0, followed by heparin withdrawal. The follow-up period was 6 months.

RESULTS

There were 63 patients who completed the study (32 in the dabigatran group and 31 in the warfarin group). In both groups, there was a statistically significant decrease in the mean pulmonary artery pressure. The mean pulmonary artery pressure at the 6-month follow-up after surgery was 24 mm Hg (interquartile range, 20.3-29.25 mm Hg) in the dabigatran group and 23 mm Hg (interquartile range, 20.0-26.3 mm Hg) in the warfarin group. The groups did not differ statistically in the deep vein thrombosis dynamics. Partial recanalization occurred in 52.0% vs 73.1% in the dabigatran and warfarin groups, respectively (P = .15). Complete recanalization occurred in 28.0% vs 19.2% in the dabigatran and warfarin groups, respectively (P = .56). The groups did not differ in the frequency of major bleeding events according to the International Society for Thrombosis and Hemostasis (0% vs 3.2% in the dabigatran and warfarin groups, respectively; P = 1.00). However, there were more nonmajor bleeding events in the warfarin group than in the dabigatran group (16.1% vs 0%, respectively; P = .02).

CONCLUSIONS

The results of the study show that dabigatran is comparable in effectiveness to warfarin. Dabigatran has greater safety in comparison with warfarin in the occurrence of all cases of bleeding in the postoperative and long-term periods. Thus, dabigatran may be recommended for the treatment and prevention of PE after CDT with RDT in patients with high and intermediate to high PE risk.

Individualized anti-thrombotic therapy for acute myocardial infarction complicated with left ventricular thrombus: A case report

BACKGROUND

Presently, there is no established standard anti-blood clot therapy for patients facing acute myocardial infarction (AMI) complicated by left ventricular thrombus (LVT). While vitamin K antagonists are the preferred choice for oral blood thinning, determining the best course of blood-thinning medication remains challenging. It is unclear if non-vitamin K antagonist oral blood thinners have different effectiveness in treating LVT. This study significantly contributes to the medical community.

CASE SUMMARY

The blood-thinning treatment of a patient with AMI and LVT was analyzed. Triple blood-thinning therapy included daily enteric-coated aspirin tablets at 0.1 g, daily clopidogrel hydrogen sulfate at 75 mg, and dabigatran etexilate at 110 mg twice daily. After 15 d, the patient's LVT did not decrease but instead increased. Clinical pharmacists comprehensively analyzed the cases from the perspective of the patient's disease status and drug interaction. The drug regimen was reformulated for the patient, replacing dabigatran etexilate with warfarin, and was administered for six months. The clinical pharmacist provided the patient with professional and standardized pharmaceutical services. The patient's condition was discharged after meeting the international normalized ratio value (2-3) criteria. The patient fully complied with the follow-up, and the time in the therapeutic range was 78.57%, with no serious adverse effects during pharmaceutical monitoring.

CONCLUSION

Warfarin proves to be an effective drug for patients with AMI complicated by LVT, and its blood-thinning course lasts for six months.

Comparing the Clinical Outcomes Observed with Rivaroxaban Versus Warfarin for the Management of Obese Patients with Non-valvular Atrial Fibrillation: a Systematic Review and Meta-analysis

BACKGROUND

Atrial fibrillation (AF) is an irregular heart rhythm which is becoming more and more common in this new era. Obesity is a risk factor for cardiovascular events, and obese patients are more at risk for stroke. The Framingham Heart Study demonstrated an increase in the developmental risk of AF by 4% for every unit (kg/m2) increase in body mass index (BMI). An anticoagulant is often required for the management of such patients. In this analysis, we aimed to systematically compare the clinical outcomes which were associated with rivaroxaban versus warfarin for the treatment of obese patients with non-valvular AF.

METHODS

PubMed, EMBASE, Web of Science, http://www.

CLINICALTRIALS

gov , Google Scholar, and Cochrane Central were the searched databases. Clinical outcomes including stroke, systemic embolism, and major bleeding were the endpoints. In this study, dichotomous data were analyzed by the RevMan software version 5.4. Risk ratio (RR) with 95% confidence interval (CI) was used for result interpretation.

RESULTS

Ten studies consisting of a total number of 168,081 obese participants were included whereby 81,332 participants were treated with rivaroxaban and 86,749 participants were treated with warfarin. The risks of ischemic (RR: 0.79, 95% CI: 0.74-0.84; P = 0.00001) and hemorrhagic stroke (RR: 0.61, 95% CI: 0.48-0.76; P = 0.0001) as well as systemic embolism (RR: 0.73, 95% CI: 0.62-0.87; P = 0.0004) were significantly lower with rivaroxaban compared to warfarin for the management of these obese patients with non-valvular AF. Rivaroxaban was also associated with a significantly lower risk of major bleeding (RR: 0.75, 95% CI: 0.65-0.87; P = 0.0001).

CONCLUSION

Based on this analysis, rivaroxaban seemed to be a better option in comparison to warfarin, due to its association with significantly lower risks of stroke and bleeding outcomes in obese patients with non-valvular AF. However, this hypothesis should further be confirmed in larger clinical trials.

Non-vitamin K oral anticoagulants versus warfarin for the treatment of left ventricular thrombus

INTRODUCTION

Left ventricular thrombus (LVT) is associated with significant morbidity and mortality. Conventional treatment comprises warfarin-mediated anticoagulation; it is unclear whether non-vitamin K oral anticoagulants (NOACs) exhibit comparable efficacy and safety. Limited data are available for Asian patients. This study compared NOACs with warfarin in terms of clinical efficacy and safety for managing LVT.

METHODS

Clinical and echocardiographic records were retrieved for all adult patients with echocardiography-confirmed LVT at a major regional centre in Hong Kong from January 2011 to January 2020. Discontinuation of anticoagulation by 1 year was recorded. Outcomes were compared between patients receiving NOACs and those receiving warfarin. Primary outcomes were cumulative mortality and net adverse clinical events (NACEs). Secondary outcomes were complete LVT resolution and percentage reduction in LVT size at 3 months.

RESULTS

Forty-three patients were included; 28 received warfarin and 15 received NOACs, with follow-up periods (mean ± standard deviation) of 20 ± 12 months and 22 ± 9 months, respectively (P=0.522). Use of NOACs was associated with significantly lower NACE risk (hazard ratio [HR]=0.111, 95% confidence interval [CI]=0.012-0.994; P=0.049) and a tendency towards lower cumulative mortality (HR=0.184, 95% CI=0.032-1.059; P=0.058). There were no significant differences in secondary outcomes. Considering LVT resolution, discontinuation of anticoagulation by 1 year was not significantly associated with different outcomes.

CONCLUSION

Non-vitamin K oral anticoagulants may be an efficacious and safe alternative to warfarin for LVT management. Future studies should explore the safety and efficacy of anticoagulation discontinuation by 1 year as an overall strategy.

Oropharyngeal Hemorrhage and Difficult Airway Management: A Decision Not to Intubate

BACKGROUND

Bleeding in the upper airways is an important cause of airway-related death. A higher incidence of airway management failure and complications after intubation attempts in the emergency department (ED) had been suggested. Airway management of patients with active oropharyngeal hemorrhage may be challenging, leading the clinician to modify the approach.

CASE REPORT

A 57-year-old woman presented to the ED with oropharyngeal hemorrhage after an extensive invasive dental procedure. She was on long-term warfarin therapy due to aortic and mitral valve replacement, which she suspended 5 days prior and restarted the day after the procedure. Besides the active bleeding, swelling, and hematoma of the face, the patient had other signs of "difficult airway," so there were serious questions on when and how to manage the airway. Several strategies to address the airway were considered, the main point being an early versus later intubation. As the patient remained clinically stable, she was conservatively managed with local hemostasis and coagulopathy reversal. The patient was transferred to the intensive care unit, where she remained stable and was successfully discharged after restart on warfarin. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: When faced with an oropharyngeal hemorrhage, emergency physicians may be compelled to secure and protect the airway. This could be achieved by planning several strategies. Nevertheless, in selected patients, and considering the circumstances, not addressing the airway is a reasonable and justifiable alternative.

Prothrombin complex concentrate administration timing in warfarin-associated intracranial hemorrhage

INTRODUCTION

Guidelines recommend "rapid" and "urgent" reversal of anticoagulation for warfarin-associated intracranial hemorrhage (ICH) treatment; however, they do not specify goals for time-to-administration. There are limited studies evaluating time to reversal, or international normalized ratio (INR) correction, on hematoma expansion and outcomes in intervals of <4 h. The purpose of this study was to evaluate the association of 4-factor prothrombin concentrate (4F-PCC) time-to-administration on rates of achieving effective hemostasis, determined by hematoma expansion, for treatment of warfarin-associated ICH.

METHODS

This was a retrospective, observational, single center study performed at a large community teaching hospital. Patients were stratified into three groups based on time of CT diagnosis of ICH to administration of 4F-PCC: <45 min, 45-90 min, and >90 min. The primary outcome was rates of achieving effective hemostasis in each group defined as a ≤20% increase in hematoma volume as estimated by a radiologist.

RESULTS

A total of 227 patients were screened for inclusion with ultimately 39 being included. Baseline characteristics were similar between groups. The primary outcome was not significantly different among groups stratified by time to 4F-PCC administration of <45 min, 45-90 min, and >90 min (85.7% vs 73.3% vs 90%, p value 0.514). There was no difference among secondary outcomes between groups including in-hospital mortality, hospital length of stay (LOS), and intensive care unit LOS.

CONCLUSION

There was no association with time-to-administration of 4F-PCC on rates of hemostasis achievement, defined as hematoma expansion of ≤20%, identified in this study.

Modified application of SAMe-TT2R2 scoring system in Asian patients with atrial fibrillation for the selection of oral anticoagulants

Background/Aims

The SAMe-TT2R2 score is used for assessing anticoagulation control (AC) quality with warfarin. However, it is hard to apply SAMe-TT2R2 score in Asian patients with atrial fibrillation (AF), because it has not been proven in those populations. This study aimed to validate the SAMe-TT2R2 score in Asian patients with AF and suggest a modified SAMe- TT2R2 score for this population.

Methods

We analyzed 710 Korean patients with AF who were using warfarin. The AC quality was assessed as the mean time in therapeutic range (TTR). Each component of SAMe-TT2R2 score was evaluated for the relationship with AC. Further clinical factors that predict AC were analyzed. Identified factors were re-assorted and constructed as SA2Me-TTR scoring system.

Results

Of the components of the SAMe-TT2R2 score, female, age, and rhythm control were associated with AC. Heart failure and renal insufficiency were newly identified factors associated with AC. The modified SA2Me-TTR score was reconstructed with the relevant risk factors (S, female gender, 1 point; A, age < 60 yr, 2 points; Me, medical history of heart failure, 1 point; T, treatment for rhythm control, 1 point; T, history of stroke or transient ischemic attack, 1 point; R, renal insufficiency, 1 point). The modified SA2Me-TTR score demonstrated an excellent relationship with the grading of AC. The modified SA2Me-TTR score ≤ 1 identified patients with good AC (hazard ratio 2.46, 95% CI 1.75-3.47).

Conclusions

The modified SA2Me-TTR score was useful for guiding oral anticoagulants selection in Asian patients with AF.

Prevalence of Guideline-Discordant Aspirin Use and Associated Adverse Events in Patients on Warfarin for Mechanical Valve Replacement

BACKGROUND

For patients on warfarin for mechanical heart valve replacement, the 2020 American College of Cardiology and American Heart Association Guidelines recommend only adding aspirin in patients with a specific indication for antiplatelet therapy. This contrasts with prior guidelines, which recommended concomitant aspirin therapy. We sought to assess the prevalence of guideline-discordant aspirin use among patients on warfarin for mechanical heart valve replacement and to compare adverse event rates among patients with and without concomitant aspirin.

METHODS

Patients on warfarin for mechanical heart valve replacement were identified from the Michigan Anticoagulation Quality Improvement Initiative registry. Patients with myocardial infarction, percutaneous coronary intervention, or coronary artery bypass within the past 12 months were excluded. Patients were divided into 2 groups based on aspirin use. Patient characteristics and bleeding and thromboembolic outcomes were compared.

RESULTS

Four hundred forty-four patients met the inclusion criteria, with 341 (76.8%) on concomitant aspirin. The aspirin group was older (50.6 vs 46.3 years, P = .028) and had more hypertension (57.8% vs 46.6%, P = .046) but other patient characteristics were similar. The aspirin group had a higher rate of bleeding events (28.3 vs 13.3 per 100 patient-years, P < .001) and bleed-related emergency department visits (11.8 vs 2.9 per 100 patient-years, P = .001) compared with the non-aspirin group. There was no observed difference in rates of ischemic stroke (0.56 vs 0.48 per 100 patient-years, P = .89).

CONCLUSIONS

A significant proportion of patients on warfarin for mechanical heart valve replacement are on guideline-discordant aspirin. Aspirin deprescribing in select patients may safely reduce bleeding events.

The safety and efficacy of nonvitamin K antagonist oral anticoagulants in morbidly obese patients with atrial fibrillation: a meta-analysis

BACKGROUND AND AIM

Atrial fibrillation (AF) is the most frequently observed cardiac arrhythmia in clinical settings. Obesity can influence the efficacy of the treatment administered, which requires a larger dose and more time to accomplish therapeutic targets due to altered pathophysiology. Our study aimed to assess the overall efficacy and safety of nonvitamin K antagonist oral anticoagulants (NOACs) versus warfarin in AF patients with morbid obesity (BMI > 40 kg/m2 and/or weight > 120 kg) to prevent complications.

METHODS

We conducted a literature search on PubMed, Web of Science, the Cochrane Library, and Scopus till October 2022 for articles addressing the efficacy and safety of NOACs versus warfarin for the treatment of AF in morbidly obese patients. We performed the meta-analysis with RevMan software version 5.4 and Open Meta Analyst. The main outcomes assessed were stroke, major bleeding, and minor bleeding after anticoagulation, as did the history of comorbidities and risk factors in morbidly obese patients. Quality assessment was performed using Cochrane's ROB-2 tool and the Newcastle-Ottawa scale.

RESULTS

Regarding major bleeding events, pooled data showed that patients taking NOACs had a significantly lower risk than patients taking warfarin (OR = 0.54, 95% CI: [0.41-0.70]; p < 0.00001). However, for minor bleeding, there was a nonsignificant effect of NOACs on reducing the risk of bleeding (OR = 0.72, 95% CI = 0.47-1.09; p = 0.12), which became highly significant in favor of NOACs after sensitivity analysis (OR = 0.55, 95% CI = 0.49-0.61]; p < 0.00001). There was a significant difference in the incidence of stroke between the NOAC group and the warfarin group (OR = 0.69, 95% CI = 0.60-0.80]; p < 0.00001). According to the results of the single-arm study analysis, the overall effect of all the outcomes was associated with a high risk of disease development in patients receiving NOACs.

CONCLUSION

Our meta-analysis showed a favorable effect of NOACs vs warfarin in morbidly obese patients. Some outcomes were not significantly different, which calls for future research to better assess their safety and efficacy in this particular weight group.

TRIAL REGISTRATION

The study was registered with PROSPERO under registration number CRD42022362493 on October 2022.

Comparison of Edoxaban and Warfarin for the Treatment of Cancer-Associated Venous Thromboembolism - A Retrospective Observational Study

BACKGROUND

Because anticoagulant drugs for ambulatory patients with cancer-associated venous thromboembolism (CAT) are limited to warfarin and direct oral anticoagulants (DOACs) in Japan, it is important to assess the outcomes of both drugs.Methods and Results:We retrospectively assessed the outcomes of CAT patients who were treated with warfarin or edoxaban between 2011 and 2017. The assessment was limited to the duration of anticoagulant administration. CAT patients who did not receive anticoagulation therapy were also compared with the warfarin and edoxaban groups. We enrolled 111 CAT patients treated with warfarin (n=58, mean age 62.6 years, mean time in therapeutic range [TTR] % 61.1) or edoxaban (n=53, mean age 64.6 years). Although venous thromboembolism (VTE) recurred in 2 warfarin-treated patients, the 2 treatment groups were not significantly different (P=0.18). Bleeding during anticoagulation therapy occurred in 6 warfarin-treated patients (2 with major bleeding) and in 5 edoxaban-treated patients (no major bleeding) (P=1.0). The non-anticoagulation group (n=37) showed a high recurrence rate (P<0.01) compared with the anticoagulant group.

CONCLUSIONS

This study showed that warfarin and edoxaban are equally effective in preventing VTE recurrence and bleeding. However, warfarin control in CAT patients presented some difficulties. This study also demonstrated the efficacy of anticoagulant drugs, compared with no anticoagulation, for CAT patients to prevent VTE recurrence.

A surgical case of anti-coagulant ileus mimicking small-bowel tumors: a case report

BACKGROUND

Anti-coagulant ileus, characterized by intramural hematoma due to excessive anti-coagulant therapy, presents a diagnostic challenge. Although previously considered uncommon, recently, reporting cases of anti-coagulant ileus have become more frequent. Herein, we report a rare surgical case of anti-coagulant ileus mimicking small-bowel tumors.

CASE PRESENTATION

A 79-year-old man was admitted to our hospital for fatigue. He had been administered warfarin for 5 months for atrial fibrillation. On admission, the patient exhibited mild epigastric tenderness. Laboratory test results revealed anemia (hemoglobin, 8.4 g/dL); unmeasurably prolonged prothrombin time (PT) with international normalized ratio (INR) > 8; and elevated soluble interleukin 2 receptor (sIL-2R) levels (849 IU/mL; normal range, 122-496 IU/mL). Abdominal plain computed tomography (CT) showed a circumferentially thickened intestinal wall at one site in the jejunum and two in the ileum. After hospitalization, bowel obstruction did not improve with conservative treatment. Suspecting small-bowel tumors such as lymphoma, the patient subsequently underwent open surgery on day 3 after admission. No obvious tumor mass was observed intra-operatively. However, only thickened and hemorrhagic segments were identified at the suspected sites. We performed partial jejunal and ileal resections of 12 and 27 cm, respectively. Histopathology confirmed submucosal congestion, edema, and hemorrhage in each area without tumor components, leading to the final diagnosis of intramural hematoma. The postoperative course was uneventful, and he was discharged on postoperative day 9. No recurrence occurred during the 5-year follow-up period.

CONCLUSIONS

We encountered a surgical case of anti-coagulant ileus, which was difficult to differentiate from malignant lymphoma based on CT findings and high sIL-2R levels. The possibility of anti-coagulant ileus should always be considered in patients on long-term anticoagulation medication and bowel obstruction with high PT-INR values.

Comparative Effectiveness and Safety of Direct Oral Anticoagulants in Low Body Weight Patients with Atrial Fibrillation: A Systematic Review and Meta-analysis

INTRODUCTION

Direct oral anticoagulant (DOAC) agents are established as the anticoagulation strategy of choice for a variety of clinical risks. Despite this, uncertainty still exists with regard to their efficacy and safety for the prevention of stroke and systemic embolism in some patient populations; most notably those with low body weight (LBW) (<60 kg or body mass index [BMI] <18 kg/m2). Currently, there is a paucity of trial and non-trial data to support a prescriptive recommendation for their use in these patient cohorts. We have carried out a pooled systematic review of the most up to date published data of patients stabilized on various DOAC analogs with the view to ascertaining the exact matrices of their efficacy and safety in these cohorts of patients.

METHODS

We initially carried out a comprehensive search of databases from inception to June 2023 for eligible studies exploring the efficacy and safety of various analogs of direct oral anticoagulants in patients with atrial fibrillation who had low body weight. Databases accessed include PubMed, EMBASE, the Science Citation Index, the Cochrane Database of Systematic Reviews, and the Database of Abstracts of Reviews of Effectiveness. We carried out a weighted comparison of derived pooled odd ratios (with their corresponding confidence intervals) of mortality outcomes between various DOACs using the random effects model.

RESULTS

Thirteen studies (n = 165,205 patients) were included in our meta-analysis. DOAC analogs were associated with increased stroke-related events, composite outcome, and mortality in low body weight patients compared to non-low body weight patients (odds ratio [OR] 1.50, 95% confidence interval [CI] 1.17-1.92), (OR 1.55, 95% CI 1.29-1.86), (OR 2.92, 95% CI 1.87-4.58), respectively. There was no significant difference in the safety outcome (major bleeding events) between the DOAC analogs (OR 1.19, 95% CI 0.93-1.52).

DISCUSSION

In this meta-analytical review comprising both real-world and randomized controlled studies, the use of DOAC analogs in low body weight patients (body weight of <60 kg or BMI<18 kg/m2) with atrial fibrillation was associated with increased risks of stroke-related events, composite outcomes, and mortality compared to non-low body weight cohorts patients. At the same time, there was no significant difference in terms of major bleeding events. This finding has provided the first resolution of pervading uncertainty surrounding the use of DOAC analogs in these patient cohorts and suggests the need for follow-up confirmatory systematic studies in this group of patients.

Association of sex with major bleeding risks in sub-Saharian anticoagulated patients with mechanical heart valves: A cohort study from the Khartoum Emergency Salam Centre

BACKGROUND

Rheumatic heart disease (RHD) with mechanical heart valve (MHV) replacement is common in Africa. However, MHV requires lifelong anticoagulation that could have a particular impact in women in reproductive age.

METHODS

We report data of a prospective observational cohort study conducted between August 2018 and September 2019 in MHV patients in the Salam Centre for Cardiac Surgery built in Khartoum by Emergency, an Italian Non-Governmental Organization, to evaluate bleeding risk, its associated determinants, and the impact of lifelong anticoagulation in fertile women.

RESULTS

We studied 3647 patients (median age 25.1 years; 53.9% female). During follow-up [median time 1.1 (0.1-1.2) years], we recorded 85 major bleedings (rate 2.16 × 100 pt-years), Major bleedings occurred more frequently among women (64/85 cases, 75.3%; rate 3.0 × 100 pt-years), compared to men (21/85 cases, 24.7%; rate 1.16 × 100 pt-years) (RR 2.6; 95% CI 1.6-4.5; p = 0.0001). Multivariate analysis was performed to identify variables associated with major bleeding, and female sex was the only risk factor significantly associated, whereas aspirin treatment and higher INR target showed a non-significant trend for higher bleeding risk. Thirty-two/85 (37.6%) of major bleedings were metrorrhagias. When we calculate the incidence of major bleedings after the exclusion of gynecological events, no sex differences in the bleeding risk were found (HR 1.3, 95% CI 0.8-2.3; p = 0.3).

CONCLUSIONS

Bleeding risk of young MHV patients on oral anticoagulant therapy is higher among women, mainly due to metrorrhagia. Women in the reproductive life are at high risk for gynecological bleeding when treated with anticoagulants.

Appropriateness of anticoagulation level in older adult patients on Warfarin: A multicenter retrospective study

Warfarin is favored over newer direct oral anticoagulants (DOACs) for many older adults. However, its use necessitates rigorous monitoring due to the fine line between toxic and therapeutic doses. Few studies have evaluated the anticoagulation quality of warfarin among elderly patients in Saudi Arabia. This study aimed to assess and identify factors affecting the anticoagulation quality of warfarin using the time in the therapeutic range (TTR) among older adults attending two hospitals in Saudi Arabia. Additionally, we aimed to evaluate differences in the anticoagulation quality of warfarin when managed by pharmacists or physicians. This cross-sectional study was conducted at King Abdullah bin Abdulaziz University Hospital (KAAUH) and King Fahad Medical City (KFMC) in Riyadh, Saudi Arabia. After calculating the TTR of each patient, the anticoagulation control level was determined using these values: a) good control: >70 %; b) intermediate control: 50-70 %; c) poor control: <50 %. A total of 132 patients prescribed warfarin therapy for different indications were included. Most patients (45.5 %) had poor control with TTRs < 50 %, while 18.2 % had intermediate control, and 36.4 % had good control. Our exploratory findings suggest that having three or more comorbidities was a significant factor associated with a poor TTR [odds ratio (OR) = 3.36; (95 % confidence interval 1.28-8.81); P = 0.014]. Thus, the anticoagulation quality of warfarin among older adult patients was poor in two Saudi Arabian tertiary hospitals, and the number of comorbidities was a potentially poor TTR predictor.

Comparison of vitamin K and non-vitamin K oral anticoagulants and the bleeding frequency in the emergency department

INTRODUCTION

Safety studies of anticoagulant therapy have so far been conducted on many subjects in controlled conditions (i.e., clinically monitored) and demonstrated the noninferiority of new ones over old anticoagulant drugs. Data on the propositions for the presence of symptoms and signs of bleeding among various anticoagulants in the emergency department indicate that these data do not match the data published so far.

AIM

The aim of the study was to investigate the differences in the frequency of bleeding and bleeding-related symptoms as a reason for emergency department attendance in patients on anticoagulant therapy.

METHODS

The study included patients from the emergency department of University Hospital for one year, who were on anticoagulant therapy and who met the inclusion criteria. Out of a total of 595 patients, 409 were on warfarin (68.74%), and the rest were taking direct oral anticoagulants (DOAC): dabigatran 71 (11.93%), rivaroxaban 66 (11.09%) and apixaban 49 (8.23%).

RESULTS

Out of 409 patients taking warfarin, 34.4% were adequately anticoagulated with the frequency of bleeding 13.7%, while in 57.2% of patients, PT INR was higher than the reference values with the frequency of bleeding 15.0%. A comparison between all DOAC groups and adequately anticoagulated warfarin patients in the frequency of bleeding and bleeding-related symptoms as a reason for emergency attendance yielded a difference that was marginally statistically significant (Pearson Chi-Square = 7.554, p = 0.052).

CONCLUSION

Monitoring the frequency of bleeding and bleeding-related symptoms in patients on oral anticoagulant therapy as a reason for emergency department attendance may be a new safety and efficacy factor in real-life patient scenarios.

New insights into the role of VKORC1 polymorphisms for optimal warfarin dose selection in Caribbean Hispanic patients through an external validation of a population PK/PD model

Warfarin, an oral anticoagulant, has been used for decades to prevent thromboembolic events. The complex interplay between CYP2C9 and VKORC1 genotypes on warfarin PK and PD properties is not fully understood in special sub-groups of patients. This study aimed to externally validate a population pharmacokinetic/pharmacodynamic (PK/PD) model for the effect of warfarin on international normalized ratio (INR) and to evaluate optimal dosing strategies based on the selected covariates in Caribbean Hispanic patients. INR, and CYP2C9 and VKORC1 genotypes from 138 patients were used to develop a population PK/PD model in NONMEM. The structural definition of a previously published PD model for INR was implemented. A numerical evaluation of the parameter-covariate relationship was performed. Simulations were conducted to determine optimal dosing strategies for each genotype combinations, focusing on achieving therapeutic INR levels. Findings revealed elevated IC50 for G/G, G/A, and A/A VKORC1 haplotypes (11.76, 10.49, and 9.22 mg/L, respectively), in this population compared to previous reports. The model-guided dosing analysis recommended daily warfarin doses of 3-5 mg for most genotypes to maintain desired INR levels, although subjects with combination of CYP2C9 and VKORC1 genotypes * 2/* 2-, * 2/* 3- and * 2/* 5-A/A would require only 1 mg daily. This research underscores the potential of population PK/PD modeling to inform personalized warfarin dosing in populations typically underrepresented in clinical studies, potentially leading to improved treatment outcomes and patient safety. By integrating genetic factors and clinical data, this approach could pave the way for more effective and tailored anticoagulation therapy in diverse patient groups.

Initiation of warfarin is associated with decreased mortality in patients with infective endocarditis: A population-based cohort study

IMPORTANCE

The use of warfarin to prevent thromboembolism in patients with infective endocarditis (IE) remains controversial due to potentially increased bleeding risks.

DESIGN

Population-based retrospective cohort study.

PARTICIPANTS

Patients aged 18 or older and diagnosed with IE in Hong Kong between January 1st, 1997 and August 31st, 2020 were included. Patients with use of any anticoagulant 30 days before IE diagnosis were excluded. Patients initiated on warfarin within 14 days of IE diagnosis and patients without warfarin use were matched for baseline characteristics using 1:1 propensity score matching.

EXPOSURE

Warfarin use within 14 days of IE diagnosis.

MAIN OUTCOMES AND MEASURES

Patients were followed up to 90 days for the outcomes of ischemic stroke, all-cause mortality, intracranial hemorrhage, and gastrointestinal bleeding. Cox regression was used to determine hazard ratios (HRs) [95 % confidence intervals (CIs)] between treatment groups. Fine-Gray competing risk regression with all-cause mortality as the competing event was performed as a sensitivity analysis. In addition to 90-day analyses, landmark analyses were performed at 30 days of follow-up.

RESULTS

The matched cohort consisted of 675 warfarin users (57.0 % male, age 59 ± 16 years) and 675 warfarin non-users (53.5 % male, age 61 ± 19 years). Warfarin users had a 50 % decreased 90-day risk in all-cause mortality (HR:0.50 [0.39-0.65]), without significantly different 90-day risks of ischemic stroke (HR:1.04 [0.70-1.53]), intracranial hemorrhage (HR:1.25 [0.77-2.04]), and gastrointestinal bleeding (HR:1.04 [0.60-1.78]). Thirty-day landmark analysis showed similar results. Competing risk regression showed significantly higher 30-day cumulative incidence of intracranial hemorrhage in warfarin users (sub-HR:3.34 [1.34-8.31]), but not at 90-day (sub-HR:1.63 [0.95-2.81]). Results from Fine-Gray regression were otherwise congruent with those from Cox regression.

CONCLUSIONS AND RELEVANCE

Warfarin initiated within 14 days of IE diagnosis was associated with significantly decreased risks of mortality but higher risks of intracranial hemorrhage, with similar risks of ischemic stroke and gastrointestinal bleeding, compared with non-use of warfarin with 14 days of IE diagnosis.

KEY POINTS

Question: Is warfarin, initiated within 14 days of a diagnosis of infective endocarditis (IE), efficacious and safe?

FINDINGS

In this propensity score-matched, population-based, prospective cohort study from Hong Kong, warfarin use within 14 days of IE diagnosis was associated with a 50 % decrease in the risk of all-cause mortality, albeit with higher risk of intracranial hemorrhage, and without significant differences in the risk of ischaemic stroke and gastrointestinal bleeding. Meaning: In patients with IE, warfarin use within 14 days of diagnosis may have mortality benefits, despite increased risks of intracranial hemorrhage.

Effectiveness and safety of short-term anticoagulant regimens after left atrial appendage occlusion: A systematic review and meta-analysis

INTRODUCTION

Left atrial appendage occlusion (LAAO) provides an alternative for poor candidates of long-term oral anticoagulant (OAC) therapy; however, anticoagulant therapy after surgical procedures has limited use due to associated uncertainties. We aimed to evaluate the effectiveness and safety of the short-term use of direct oral anticoagulant (DOAC) and warfarin after LAAO.

METHOD

Electronic databases such as PubMed, Embase, Medline, and Cochrane Library databases were searched up to November 11, 2022. Our study compared DOAC therapy and warfarin in patients after LAAO. A meta-analysis was conducted with the Review Manager software (version 5.4).

RESULTS

The meta-analysis included 13 cohort studies with a total of 32,607 patients. Our findings indicated that the incidence of stroke/TIA/SE, peri-device leaks>5 mm, device-related thrombosis, and all-cause mortality were not significantly different between the two groups after LAAO (P > 0.05). The DOAC group had a significantly lower incidence of major bleeding (OR = 0.83, 95 % CI: 0.74-0.94, P = 0.003), any bleeding (OR = 0.34, 95 % CI: 0.23-0.51, P < 0.001), stroke/TIA/SE and major bleeding (OR = 0.57, 95 % CI: 0.34-0.95, P = 0.03), and any major adverse event (OR = 0.89, 95 % CI:0.82-0.97, P = 0.010) than the warfarin group. The subgroup analysis revealed that the rate of stroke/TIA/SE was similar in the two groups in terms of the different regions, follow-up time, study type, anticoagulant strategy, and bleeding risk. The incidence of major bleeding in the DOAC group was significantly lower than that in the warfarin group in North America, as well as at follow-up period ≤6 months, retrospective cohort, HAS-BLED average score ≥ 3. In addition, the risk of major bleeding was higher with the combination of OAC and single antiplatelet therapy (SAPT) than with OAC alone. Finally, in the North American region, retrospective cohort, and HAS-BLED average score ≥ 3, the incidence of any serious adverse event in the DOAC group was still significantly lower than that in the warfarin group.

CONCLUSION

Compared to warfarin, DOAC reduced the risk of major bleeding and any serious adverse event in patients after LAAO. This advantage was particularly notable in North America and high-risk populations for bleeding. In addition, the incidence of device-related thrombosis, peri-device leaks, stroke/TIA/SE and all-cause mortality were similar in both groups. The risk of major bleeding was lower in patients taking OAC alone compared with those taking OAC plus SAPT, without increasing the risk of thrombosis.

Effectiveness and safety of apixaban and rivaroxaban vs warfarin in patients with atrial fibrillation and chronic kidney disease

BACKGROUND

Randomized controlled trials (RCTs) of direct oral anticoagulants (DOACs) included a low proportion of atrial fibrillation (AF) patients with chronic kidney disease (CKD), and suggested that DOACs are safe and effective in patients with mild-to-moderate CKD. In a metanalysis of RCTs and observational studies, DOACs were associated with better efficacy (vs warfarin) in early CKD and had similar efficacy and safety profiles in patients with stages IV-V CKD. But few studies have provided data on the safety and effectiveness of each DOAC vs warfarin in patients with stage III CKD. The effectiveness and safety of DOACs in those patients are still subject to debate.

AIM

To assess and compare the effectiveness and safety of apixaban and rivaroxaban vs warfarin in this patient population.

METHODS

A cohort of patients with an inpatient or outpatient code for AF and stage III CKD who were newly prescribed apixaban and rivaroxaban was created using the administrative databases from the Quebec province of Canada between 2013 and 2017. The primary effectiveness outcome was a composite of ischemic stroke, systemic embolism, and death, whereas the primary safety outcome was a composite of major bleeding within a year of DOAC vs warfarin initiation. Treatment groups were compared in an under-treatment analysis using inverse probability of treatment weighting and Cox proportional hazards.

RESULTS

A total of 8899 included patients filled out a new oral anticoagulation therapy claim; 3335 for warfarin and 5564 for DOACs. Compared with warfarin, 15 mg and 20 mg rivaroxaban presented a similar effectiveness and safety composite risk. Apixaban 5.0 mg was associated with a lower effectiveness composite risk [Hazard ratio (HR) 0.76; 95% confidence interval (CI): 0.65-0.88] and a similar safety risk (HR 0.94; 95%CI: 0.66-1.35). Apixaban 2.5 mg was associated with a similar effectiveness composite (HR 1.00; 95%CI: 0.79-1.26) and a lower safety risk (HR 0.65; 95%CI: 0.43-0.99. Although, apixaban 5.0 mg was associated with a better effectiveness (HR 0.76; 95%CI: 0.65-0.88), but a similar safety risk profile (HR 0.94; 95%CI: 0.66-1.35). The observed improvement in the effectiveness composite for apixaban 5.0 mg was driven by a reduction in mortality (HR 0.61; 95%CI: 0.43-0.88).

CONCLUSION

In comparison with warfarin, rivaroxaban and apixaban appear to be effective and safe in AF patients with stage III CKD.

Development and validation of the Chinese oral anticoagulants knowledge tool (C-OAKT): A pilot study

Objective

To develop and validate an oral anticoagulant knowledge tool for Chinese-speaking patients treated with warfarin or direct oral anticoagulants (DOACs) in Hong Kong.

Method

This pilot validation study consisted of the following three phases: (1) the development of a knowledge tool and content validity assessment; (2) a pilot study of 200 participants, consisting of 100 patients taking warfarin or DOACs, 50 pharmacists, and 50 members of the general public; and (3) known-group validity and reliability assessments.

Results

A 19-item "Chinese Oral Anticoagulants Knowledge Tool (C-OAKT)" was developed with a scale content validity index of 0.95. The mean score for known-group validity was significantly higher in the pharmacist group than the patient groups, and the patient groups scored significantly higher than the general public (mean ± standard deviation [SD] = 90.00 ± 7.11 vs. 51.55 ± 17.49 vs. 19.0 ± 15.42, respectively; p < 0.001). The mean score was higher for patients who attended a pharmacist-managed anticoagulant therapy management clinic (PAC) than for non-PAC patients (mean ± SD = 56.80 ± 13.60 vs. 46.30 ± 9.43; p = 0.004). An analysis of internal consistency showed a Cronbach's alpha value of 0.86.

Conclusion

The results of the pilot validation study suggested that the C-OAKT is a valid and reliable instrument for assessing patients' knowledge of oral anticoagulants in ambulatory care settings.

Innovations

This is the first validated Chinese version of an anticoagulant knowledge assessment tool. This tool will be utilized in public hospitals in Hong Kong, and will facilitate future research exploring the relationship between anticoagulant knowledge and patient-related outcomes.

Left atrial Thrombus formation after discontinuation of anticoagulation in patient with severe bioprosthetic mitral stenosis

BACKGROUND

Mitral valve stenosis can be a highly symptomatic condition with significant complications if left untreated. In such cases, mitral valve replacement with a bioprosthetic or mechanical valve may be a viable solution to prevent progressive disease. Current guidelines do not recommend continued anticoagulation beyond 6 months for patients who have undergone bioprosthetic valve replacement without a separate indication for anticoagulation. With this case discussion we aim to 1) Review the current indications for anticoagulation for bioprosthetic mitral valves in patients without atrial fibrillation and 2) Discuss the constellation of comorbidities that may affect the decision to begin anticoagulation therapy.

CASE PRESENTATION

We present a case describing a 55-year-old male with end-stage renal disease, coronary artery disease with coronary artery bypass graft surgery, and bioprosthetic mitral valve replacement 2 years prior with rapid degeneration of the replaced valve and on warfarin without a clear indication for anticoagulation. The patient was admitted for symptomatic, severe mitral stenosis and consideration of transcatheter mitral valve-in-valve replacement. During hospital admission, warfarin was discontinued and replaced with prophylactic anticoagulation. However, 8 days after warfarin cessation an intraoperative transesophageal echocardiography revealed a newly developed large left atrial thrombus leading to cancellation of the planned operation.

CONCLUSIONS

This patient developed a left atrial thrombus after discontinuing warfarin in the setting of rapidly deteriorating bioprosthetic valve stenosis and vascular comorbidities. The decision to discontinue warfarin was made in concordance with current guidelines, which do not indicate systemic anticoagulation post 3-6 months after bioprosthetic valve replacement without separate indication for anticoagulation. This case identifies the need to investigate rebound hypercoagulability and further risk stratify comorbidities which may independently increase the risk of clot formation in the setting of severe mitral valve stenosis.

warfarin - propensity score matching study

BACKGROUND

Venous thromboembolic disease (VTE) is characterized by obstruction of venous blood flow by a thrombus. Survival data, frequency of disease recurrence, and bleeding rate in patients on anticoagulant therapy with warfarin compared to rivaroxaban in the Latin American population are limited in VTE.

METHODS

A retrospective cohort study with propensity score matching analysis was conducted in patients with pulmonary embolism and/or deep vein thrombosis anticoagulated with warfarin or rivaroxaban treated. Survival analysis was performed using a Kaplan-Meier curve for each of the intervention groups, and it was compared using a Log Rank test.

RESULTS

Of 2193 potentially eligible patients with a suspected diagnosis of VTE, 505 patients entered the analysis; of these, 285 subjects were managed with warfarin and 220 anticoagulated with rivaroxaban. Major bleeding at 12 months occurred in 2.7% (6/220) of patients treated with Rivaroxaban, compared to 10.2% (29/285) in the Warfarin group in the unmatched population (p = 0.001). In the matched population, bleeding at 12 months occurred in 2.9% (6/209) of patients on Rivaroxaban and in 11.0% (23/209) of patients on Warfarin (p = 0.001). The survival rates at 6 months were 97.1% for Rivaroxaban and 97.6% for Warfarin (p = 0.76). At 12 months, the survival rates were 94.7% for Rivaroxaban and 95.7% for Warfarin (p = 0.61).

CONCLUSION

In the treatment of VTE, there is no differences on 6 and 12-month survival or a reduction in the occurrence of new thromboembolic events when comparing rivaroxaban to warfarin. However, a lower risk of major bleeding is observed at 12 months with Rivaroxaban.

Clinical value of a tool for managing oral anticoagulation in nonvalvular atrial fibrillation in primary health care. Randomized clinical trial

INTRODUCTION AND OBJECTIVES

The management of atrial fibrillation is complex and requires improvement at strategic points, such as in the control of patients treated with vitamin K antagonists. The aim of this study was to evaluate the impact on health outcomes of a nonvalvular atrial fibrillation decision support tool based on visualization of the time in therapeutic range in primary care.

METHODS

The present randomized clinical trial was conducted in 2018 with a 1-year follow-up in 325 primary care centers in Catalonia. In the intervention centers, the decision support tool was installed to control the time in therapeutic range of patients treated with vitamin K antagonists. The tool was not visualized in the control group. This clinical trial was registered with ClinicalTrials.gov (NCT03367325).

RESULTS

In total, 44 556 patients were studied. The intervention protected against admission for stroke (adjusted odds ratio [OR], 0.70; 95% confidence interval [95%CI], 0.55-0.88). The number needed to treat was 3502 (95%CI, 3305-3725) while the number of admissions for stroke avoided was 12.63 (95%CI, 11.88-13.38). The intervention also protected against mortality (adjusted OR, 0.78; 95%CI, 0.67-0.90), with a number needed to treat of 13 687 (95%CI, 10 789-18 714) and number of deaths avoided of 3.23 (95%CI, 2.36-4.10).

CONCLUSIONS

The decision support tool was associated with slight reductions in the numbers of admissions for ischemic stroke and mortality. Although the follow-up time was short and the effect of the intervention was small, the results are valuable and could improve implementation of the tool.