Warfarin Treatment Research Articles

Live-imaging studies reveal how microclots and the associated inflammatory response enhance cancer cell extravasation.

Previous clinical studies and work in mouse models have indicated that platelets and microclots might enable the recruitment of immune cells to the pre-metastatic cancer niche, leading to efficacious extravasation of cancer cells through the vessel wall. Here, we investigated the interaction between platelets, endothelial cells, inflammatory cells, and engrafted human and zebrafish cancer cells by live-imaging studies in translucent zebrafish larvae, and show how clotting (and clot resolution) act as foci and as triggers for extravasation. Fluorescent tagging in each lineage revealed their dynamic behaviour and potential roles in these events, and we tested function by genetic and drug knockdown of the contributing players. Morpholino knockdown of fibrinogen subunit α (fga) and warfarin treatment to inhibit clotting both abrogated extravasation of cancer cells. The inflammatory phenotype appeared fundamental, and we show that forcing a pro-inflammatory, tnfa-positive phenotype is inhibitory to extravasation of cancer cells.

Plasma type I collagen α1 chain in relation to coronary artery disease: findings from a prospective population-based cohort and an acute myocardial infarction prospective cohort in Sweden

ObjectivesTo investigate the association between type I collagen α1 chain (COL1α1) levels and coronary artery disease (CAD) by using absolute quantification in plasma. Also, to investigate the correlates of COL1α1...

Safety and Efficacy of Novel Oral Anticoagulants as Compared to Warfarin in Treatment of Atrial Fibrillation

BACKGROUND - Novel oral anticoagulants (NOACs) are a class of medications used to prevent blood clots thereby various studies have demonstrated their potential benefit in their use in atrial fibrillation. They act by inhibiting clotting factors such as factor Xa or Thrombin. Unlike traditional anticoagulants like Vitamin K antagonist (Warfarin), NOACs have a more predictable effect and require less frequent monitoring. OBJECTIVE – We aim to explore the safety and efficacy of Novel oral anticoagulants as compared to warfarin in the treatment of atrial fibrillation. Additionally, a comparative analysis among NOACs was conducted to determine the most superior among them. METHODS – We performed a pairwise systematic review in patients with atrial fibrillation undergoing anticoagulation with the help of NOAC as compared to those undergoing anticoagulation on Warfarin by analyzing various electronic databases from 2005 till 2023 and filtered 11 studies having 70,801 sample size distributed comparably among the two groups based on our inclusion criteria. RESULTS – There was a slight difference between the safety and efficacy of the NOAC and Warfarin groups. Among the participants, 3019 individuals (8.93%) who were administered Warfarin experienced major bleeding complications, in contrast to 2690 participants (7.26%) who were on NOACs. Regarding the occurrence of stroke, the Warfarin group observed a rate of 987 cases (2.92%), while the NOAC group had 1119 instances (3.02%) of stroke. CONCLUSION – The results of recent NOACs studies emphasizes on the superiority of them as compared to warfarin in both rapid onset of action as well as better patient compliance. Our review suggests a lower risk of bleeding but a slightly higher risk of stroke occurrence in NOACs as compared to the Warfarin group, thereby showing their superiority in clinical utility, though more robust clinical trials are required to establish long-term benefits.

Clinical Outcomes of Direct Oral Anticoagulants vs Warfarin for Extended Treatment of Venous Thromboembolism

Extending the duration of oral anticoagulation for venous thromboembolism (VTE) beyond the initial 3 to 6 months of treatment is often recommended, but it is not clear whether clinical outcomes differ when using direct oral anticoagulants (DOACs) or warfarin. To compare rates of recurrent VTE, hospitalizations for hemorrhage, and all-cause death among adults prescribed DOACs or warfarin whose anticoagulant treatment was extended beyond 6 months after acute VTE. This cohort study was conducted in 2 integrated health care delivery systems in California with adults aged 18 years or older who received a diagnosis of incident VTE between 2010 and 2018 and completed at least 6 months of oral anticoagulant treatment with DOACs or warfarin. Patients were followed from the end of the initial 6-month treatment period until discontinuation of anticoagulation, occurrence of an outcome event, health plan disenrollment, or end of the study follow-up period (December 31, 2019). Data were obtained from the Kaiser Permanente Virtual Data Warehouse and electronic health records. Data analysis was conducted from March 2022 to January 2023. Dispensed prescriptions of DOACs or warfarin after a 6-month initial treatment for VTE. The primary outcomes were rates per 100 person-years of recurrent VTE, hospitalizations for hemorrhage, and all-cause death. Comparison of DOAC and warfarin outcomes were performed using multivariable Cox proportional hazards regression. A total of 18 495 patients (5477 [29.6%] aged ≥75 years; 8973 women [48.5%]) with VTE who were treated with at least 6 months of anticoagulation were identified, of whom 2134 (11.5%) were receiving DOAC therapy and 16 361 (88.5%) were receiving warfarin therapy. Unadjusted event rates were lower for patients receiving DOAC therapy than warfarin therapy for recurrent VTE (event rate per 100 person-years, 2.92 [95% CI, 2.29-3.54] vs 4.14 [95% CI, 3.90-4.38]), hospitalizations for hemorrhage (event rate per 100 person-years, 1.02 [95% CI, 0.66-1.39] vs 1.81 [95% CI, 1.66-1.97]), and all-cause death (event rate per 100 person-years, 3.79 [95% CI, 3.09-4.49] vs 5.40 [95% CI, 5.13-5.66]). After multivariable adjustment, DOAC treatment was associated with a lower risk of recurrent VTE (adjusted hazard ratio [aHR], 0.66; 95% CI, 0.52-0.82). For patients prescribed DOAC treatment, the risks of hospitalization for hemorrhage (aHR, 0.79; 95% CI, 0.54-1.17) and all-cause death (aHR, 0.96; 95% CI, 0.78-1.19) were not significantly different than those for patients prescribed warfarin treatment. In this cohort study of patients with VTE who continued warfarin or DOAC anticoagulation beyond 6 months, DOAC treatment was associated with a lower risk of recurrent VTE, supporting the use of DOACs for the extended treatment of VTE in terms of clinical outcomes.

A "Bundle of Care" to Improve Anticoagulation Control in Patients Receiving Warfarin in Uganda and South Africa: Protocol for an Implementation Study.

The quality of warfarin anticoagulation among Sub-Saharan African patients is suboptimal. This is due to several factors, including a lack of standardized dosing algorithms, difficulty in providing timely international normalized ratio (INR) results, a lack of patient feedback on their experiences with treatment, a lack of education on adherence, and inadequate knowledge and training of health care workers. Low quality of warfarin anticoagulation, expressed as time in therapeutic range (TTR), is associated with higher adverse event rates, including bleeding and thrombosis, and ultimately, increased morbidity and mortality. Processes and interventions that improve this situation are urgently needed. This study aims to evaluate the implementation of the "warfarin bundle," a package of interventions to improve the quality of anticoagulation and thereby clinical outcomes. The primary outcome for this study is TTR over the initial 3 months of warfarin therapy. Patients aged 18 years or older who are newly initiated on warfarin for venous thromboembolism, atrial fibrillation, or valvular heart disease will be enrolled and followed up for 3 months at clinics in Cape Town, South Africa, and Kampala, Uganda, where the warfarin bundle is implemented. A retrospective review of the clinical records of patients on warfarin treatment before implementation (controls) will be used for comparison. This study uses a mixed methods approach of the implementation of patient- and process-centered activities to improve the quality of anticoagulation. Patient-centered activities include the use of clinical dosing algorithms, adherence support, and root cause analysis, whereas process-centered activities include point-of-care INR testing, staff training, and patient education and training. We will assess the impact of these interventions by comparing the TTR and safety outcomes across the 2 groups, as well as the cost-effectiveness and acceptability of the package. We started recruitment in June 2021 and stopped in August 2022, having recruited 167 participants. We obtained ethics approval from the University of Cape Town Faculty of Health Sciences Human Research Ethics Committee, the Provincial Health Research Committees in South Africa, the Joint Clinical Research Centre Institutional Review Board, Kampala, and the University of Liverpool Research Ethics Committee. As of February 2023, data cleaning and formal analysis are underway. We expect to publish the full results by December 2023. We anticipate that the "bundle of care," which includes a clinical algorithm to guide individualized dosing of warfarin, will improve INR control and TTR of patients in Uganda and South Africa. We will use these findings to design a larger, multisite clinical trial across several Sub-Saharan African countries. DERR1-10.2196/46710.

Warfarin treatment quality and outcomes in patients with non-valvular atrial fibrillation and CKD G3-G5D

IntroductionWarfarin treatment quality is calculated as time in therapeutic range (TTR). TTR ≥ 70 % is considered reducing the risk of adverse events for patients with atrial fibrillation (AF). The association of TTR and adverse events in chronic kidney disease (CKD) is however poorly investigated. The aim is to explore this further. Materials and methodsSwedish cohort study based on national healthcare registers between 2009 and 2018, including Swedish Renal Registry, Swedish Stroke Register and AuriculA - the Swedish national quality register for AF and anticoagulation. Investigating the effect of individual TTR (iTTR) and iTTR ≥ 70 % versus <70 % on the risk of ischemic stroke, major bleeding and death for patients with CKD GFR category 3–5 (G3-G5) including patients on dialysis (G5D) and non-valvular AF (NVAF). ResultsOf 2379 included patients 21.9 % had G3, 47.5 % G4, 10.8 % G5 and 19.8 % G5D. TTR in G3 was 75.6 %, G4 72.2 %, G5 67.6 % and G5D 62.0 %. Increase by 10 percentage points iTTR conferred lower risk of major bleeding, ischemic stroke and death for all patients (hazard ratio 0.91 (95 % Confidence interval 0.87–0.94), 0.92 (0.85–0.99) and 0.88 (0.85–0.90)). iTTR≥ 70 % versus <70 % was associated with lower risk of bleeding and death in all patients (0.63 (0.51–0.77) and (0.51 (0.43–0.61)), and a non-significant tendency towards lower stroke risk (0.67 (0.43–1.06)). ConclusionsWarfarin treatment quality worsens with decreasing GFR. Higher iTTR confers lower risk of bleeding, ischemic stroke and death in patients with NVAF and G3-G5D. iTTR ≥ 70 % was associated with better safety profile. Close monitoring of patients with CKD on warfarin is recommended.

A new model (Alfalfa-Warfarin-GIB) for predicting the risk of major gastrointestinal bleeding in warfarin patients.

This study aimed to analyze the factors influencing warfarin-related major gastrointestinal bleeding (GIB) and to develop a score that would provide a reference for assessing the risk of major GIB associated with warfarin treatment. This was a retrospective analysis of clinical and follow-up data from warfarin-treated patients. Scores were analyzed using logistic regression. The area under the subject working characteristic curve (AUC), sensitivity, specificity, and Hosmer-Lemeshow test were used to evaluate the scoring performance. A total of 1591 patients who met the requirements for warfarin use were included in this study, and 46 developed major GIB. After univariate analysis as well as multivariate logistic regression analysis, nine factors were found to be associated with increased risk of major GIB, namely age ≥ 65years, history of peptic ulcer, history of major bleeding, abnormal liver function, abnormal renal function, cancer, anemia, labile international normalized ratio, and combination of antiplatelet agents/non-steroidal anti-inflammatory drugs. The Alfalfa-Warfarin-GIB score was constructed using these nine factors. The AUC and Bootstrap method-corrected AUC of the Alfalfa-Warfarin-GIB score were 0.916 (95% CI: 0.862-0.970, P < 0.001) and 0.919 (95% CI: 0.860-0.967, P < 0.001), respectively, which were higher than those of the HAS-BLED score (AUC = 0.868, 95% CI: 0.812-0.924, P < 0.001). Based on nine risk factors, the Alfalfa-Warfarin-GIB score was constructed to predict the risk of warfarin-related major GIB. The newly developed Alfalfa-Warfarin-GIB score has a better predictive value than the HAS-BLED score and may be an effective tool to help reduce the occurrence of major GIB in patients on warfarin.

N-acetylcysteine ameliorates hematuria-associated tubulointerstitial injury in 5/6 nephrectomy mice.

Chronic kidney disease (CKD) is characterized by increased interstitial fibrosis and tubular atrophy (IFTA) in the kidney. Chronic hematuria is a hallmark of several human kidney diseases and often is seen in patients on anticoagulation therapy. We had previously demonstrated that chronic hematuria associated with warfarin increases IFTA in 5/6 nephrectomy (5/6NE) rats, and such treatment increases reactive oxygen species (ROS) in the kidney. The goal of this study was to evaluate the effects of the antioxidant N-acetylcysteine (NAC) on the progression of IFTA in 5/6NE mice. 5/6NE C57BL/6 and 5/6NE 129S1/SvImJ mice were treated with warfarin alone or with warfarin and NAC for 23 weeks. Serum creatinine (SCr), hematuria, blood pressure (BP), and ROSs in the kidney were measured; kidney morphology was evaluated. Warfarin doses were titrated to achieve prothrombin time (PT) increase to the levels seen with therapeutic human doses. Warfarin treatment resulted in an increased SCr, systolic BP, hematuria, expression of TGF-ß and ROS in the kidney in both mouse strains. Tumor necrosis factor alpha (TNF-ɑ) levels in the serum were increased in 5/6NE mice treated with warfarin. IFTA was increased as compared with control 5/6NE mice, and this increase in IFTA was more prominent in 129S1/SvImJ than in C57BL/6 mice. NAC ameliorated the warfarin-associated increase in SCr and BP but not hematuria. IFTA, TGF-ß, and ROS in the kidney as well as TNF-ɑ levels in the serum were reduced in mice treated with NAC and warfarin as compared to mice treated with warfarin alone. NAC mitigates the increase in SCr and IFTA in mice with chronic hematuria by reducing oxidative stress in the kidney. This data open novel possibilities for treatments in CKD patients.

Frequency of prothrombin time-international normalized ratio monitoring and the long-term prognosis in patients with mechanical valve replacement

BackgroundThe study aimed to assess the correlation between the monitoring frequency of PT-INR and the long-term prognosis in patients with mechanical heart valve (MHV) replacement after discharge.MethodsThis single-center, observational study enrolled patients who underwent MHV replacement and discharged from June 2015 to May 2018. Patients or their corresponding family members were followed with a telephone questionnaire survey in July-October 2020. Based on monitoring intervals, patients were divided into frequent monitoring (FM) group (≤ 1 month) and less frequent monitoring (LFM) group (> 1 month). The primary endpoint was the composite of thromboembolic event, major bleeding or all-cause death. The secondary endpoints were thromboembolic event, major bleeding or all-cause death, respectively.ResultsA total of 188 patients were included in the final analysis. The median follow-up duration was 3.6 years (Interquartile range: 2.6 to 4.4 years). 104 (55.3%) patients and 84 (44.7%) patients were classified into the FM group and the LFM group, respectively. The FM group had a significantly lower incidence of the primary endpoint than the LFM group (3.74 vs. 1.16 per 100 patient-years, adjusted HR: 3.31 [95% CI 1.05–10.42, P = 0.041]). Secondary analysis revealed that the risk of thromboembolic events and all-cause death were also reduced in the FM group.ConclusionsThe management of warfarin treatment in patients after MHV replacement remains challenging. Patients with less frequent monitoring of PT-INR might have worse clinical prognosis than those with frequent PT-INR monitoring.

Efficacy of Warfarin Therapy Guided by Pharmacogenetics: A Real-world Investigation Among Han Taiwanese

The anticoagulation activity of warfarin in populations with CYP2C9, VKORC1, and CYP4F2 variants differs between individuals and is correlated with poor international normalized ratio (INR) control. Pharmacogenetics-guided warfarin dosing has been successfully developed for patients with genetic variations in recent years. However, few real-world data have been used to investigate the INR and warfarin dosage and the time to target INR. This study examined the largest collection of genetic and clinical real-world data related to warfarin to provide further evidence supporting the benefits of pharmacogenetics in clinical outcomes. We retrieved a total of 69,610 INR-warfarin records after the index date from 2,613 patients in the China Medical University Hospital database between January 2003 and December 2019. Each INR reading was obtained from the latest laboratory data after the hospital visit date. Patients with a history of malignant neoplasms or pregnancy before the index date were excluded, as were patients without data on INR measurements after the fifth day of prescription, genetic information, or gender variables. The primary outcomes were the INR and warfarin dosage during days 7, 14, 28, 56, and 84 after prescription. The secondary outcome was the time required to reach the INR ranges of 1.5 to 3.0 and >4.0. A total of 59,643 INR-warfarin records from 2188 patients were retrieved. The average INR was higher for homozygous carriers of the minor allele at CYP2C9 and VKORC1 during the first 7 days (1.83 [1.03] [CYP2C9*1] and 2.46 [1.44] [CYP2C9*3], P < 0.001; 1.39 [0.36] [rs9923231 G/G], 1.55 [0.79] [rs9923231 G/A], and 1.96 [1.13] [rs9923231 A/A], P < 0.001) than for the wild-type allele. These patients with variants required lower warfarin doses than those with the wild-type allele during the first 28 days. CYP4F2 variant patients seemed to require higher doses of warfarin than those in the wild-type group; however, no significant difference in the average INR was observed (1.95 [1.14] [homozygous V433 carriers], 1.78 [0.98] [heterozygous V433M carriers], and 1.66 [0.91] [homozygous M433 carriers], P=0.016). Our study indicates that genetic variants in the Han population may enhance warfarin responsiveness, which holds clinical relevance. An increased warfarin dosage was not linked to a shorter time to therapeutic INR between CYP4F2 variant patients and those with a wild-type allele. Assessing CYP2C9 and VKORC1 genetic polymorphisms before initiating warfarin treatment in real-world practice is essential for potentially vulnerable patients and is likely to optimize therapeutic dosing.

How good is time-in-therapeutic-range defined warfarin treatment compared to standard dose direct oral anticoagulants? Incidence of stroke in atrial fibrillation in a nationwide registry study

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): The Finnish Foundation for Cardiovascular Research, and Helsinki and Uusimaa Hospital District research fund. Background and aims Direct oral anticoagulants (DOACs) have largely replaced warfarin in patients with atrial fibrillation (AF) to reduce risk of stroke. However, it is not known whether DOACs are more efficacious in preventing stroke or safer than good-quality warfarin treatment with high time in therapeutic range (TTR). Methods The Finnish AntiCoagulation in Atrial Fibrillation (FinACAF) is a nationwide study of AF patients that combines data from several Finnish health care registers. We analyzed all new-onset AF patients in Finland from January 2011 to December 2018 with laboratory data available. Comorbidities, concomitant medications and CHA2DS2-VASc -scores were recorded until date of AF diagnosis. OAC purchases from diagnosis of AF to the end of study were analyzed. ICD-10 diagnoses for stroke (ischemic or hemorrhagic) or transient ischemic attack during OAC use were analyzed until maximum follow-up of 730 days. Confounding factors by baseline characteristics as well as medications were taken in account by use of an inverse probability of treatment weighted analysis. For warfarin users, time in therapeutic range (TTR) was calculated and patient quartiles by TTR were assigned. Rate of stroke in different TTR quartiles for warfarin users were compared to standard dose dabigatran (150 mg bd.), apixaban (5mg bd.) and rivaroxaban (20mg od.). Results Altogether, 74 008 new-onset AF patients with OAC therapy (50.4 % male, mean age 73.0 years, 43 549 on warfarin, with mean TTR 66% and median TTR 72%) were followed for 109 143 patient years (py). Rate of stroke among patients with standard dose direct oral anticoagulants was 6.0/100 py for dabigatran (n=4545), 6.2/100 py for apixaban (n=12 426) and 4.0/100 py for rivaroxaban (n=12 950). In the TTR quartiles of patients on warfarin, rates of stroke were 9.3, 7.2, 5.5 and 4.3/100 py from the lowest (mean TTR 32%) to the highest quartile (mean TTR 90%), respectively. The weighted rates of stroke were 6.3, 6.1 and 4.5/100 py for dabigatran, apixaban and rivaroxaban, respectively, and for warfarin from the lowest to the highest quartile: 8.8, 7.0, 5.5 and 4.2/100 py, respectively. The Figure provides survival probabilities (crude rates) of stroke with confidence intervals of the analysed OAC groups. Conclusion Rates of stroke were evidently the highest among patients on warfarin in the two lowest TTR quartiles, while the differences between high TTR groups and standard dose DOACs were only modest.

Lower dose direct oral anticoagulation or warfarin in atrial fibrillation. Which one is the best when time on therapeutic range information is available?

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): Helsinki and Uusimaa Hospital District (TYH2019309) and The Finnish Foundation for Cardiovascular Research Background and aims Elderly patients with atrial fibrillation (AF) and patients with renal failure – for example – are recommended to use reduced doses of direct oral anticoagulants (DOACs) to minimize risk of ischemic stroke and hemorrhagic complications. However, it is not known whether DOACs used with reduced doses are better than warfarin when the quality of warfarin treatment is available by means of time in therapeutic range (TTR). Methods The Finnish AntiCoagulation in Atrial Fibrillation (FinACAF) is a nationwide study of AF patients that combines data from several Finnish health care registers. Here all new-onset AF patients from 2011 to 2018 on reduced dose DOAC in Finland and patients on warfarin with TTR data were analyzed. Comorbidities, concomitant medications and CHA2DS2-VASc -scores were recorded until date of AF diagnosis. OAC purchases from diagnosis of AF to the end of study were analyzed. ICD-10 diagnoses for stroke (ischemic or hemorrhagic) or transient ischemic attack during OAC-use were analyzed until maximum follow-up of 730 days. Crude rates of stroke as well as weighted rates are provided. To avoid confounding by baseline characteristics as well as medications, an inverse probability of treatment weighted analysis was made. For warfarin users with sufficient laboratory data, time in therapeutic range (TTR) was calculated and patient quartiles by TTR were assigned. Results Altogether, 52 204 new-onset AF patients with OAC therapy (46.1 % male, mean age 75.7 years, 43 549 on warfarin - with mean TTR 66%, median TTR 72%) were followed for 91 549 patient-years (py). Rate of stroke among patients on lower dose DOACs was 5.2/100 patient years (py) for dabigatran (n=2 672), 4.3/100 py for apixaban (n=3 936), 3.9 /100 py for rivaroxaban (n=1 866). In the TTR-quartiles of patients on warfarin, the rates of stroke were 9.3, 7.2, 5.5 and 4.3 /100 py from the lowest (mean TTR 32%) to the highest quartile (mean TTR 90%), respectively. The weighted rates of stroke were 5.1, 3.5 and 3.1/100 py for dabigatran, apixaban and rivaroxaban, respectively and for warfarin from the lowest to the highest quartile: 8.7, 7.0, 5.4 and 4.1/100 py. Figure provides survival probabilities of the OAC groups with confidence limits. Conclusion In AF patients treated with OAC, the rates of stroke were highest among patients on warfarin at the lowest TTR quartiles, while the differences between high TTR groups and lower dose DOACs were only modest.

Missense VKOR mutants exhibit severe warfarin resistance but lack VKCFD via shifting to an aberrantly reduced state.

Missense vitamin K epoxide reductase (VKOR) mutations in patients cause resistance to warfarin treatment but not abnormal bleeding due to defective VKOR activity. The underlying mechanism of these phenotypes remains unknown. Here we show that the redox state of these mutants is essential to their activity and warfarin resistance. Using a mass spectrometry-based footprinting method, we found that severe warfarin-resistant mutations change the VKOR active site to an aberrantly reduced state in cells. Molecular dynamics simulation based on our recent crystal structures of VKOR reveals that these mutations induce an artificial opening of the protein conformation that increases access of small molecules, enabling them to reduce the active site and generating constitutive activity uninhibited by warfarin. Increased activity also compensates for the weakened substrate binding caused by these mutations, thereby maintaining normal VKOR function. The uninhibited nature of severe resistance mutations suggests that patients showing signs of such mutations should be treated by alternative anticoagulation strategies.

Does prescribing apixaban or rivaroxaban versus warfarin for patients diagnosed with atrial fibrillation save health system costs? A multivalued treatment effects analysis.

Non-valvular atrial fibrillation (AF) is a common heart arrhythmia in the elderly population. AF patients are at high-risk of ischemic strokes, but oral anticoagulant (OAC) therapy reduces such risks. Warfarin had been the standard OAC for AF patients, however its effectiveness is highly variable and dependent on close monitoring of the anticoagulant response. Newer OACs such as rivaroxaban and apixaban address these drawbacks but are more costly. It is uncertain which OAC therapy for AF is cost-saving from the healthcare system perspective. We followed a cohort of patients in Ontario, Canada, aged ≥ 66 who were newly diagnosed with AF and prescribed OACs between 2012 and 2017. We used a two-stage estimation procedure. First, we account for the patient selection into OACs using a multinomial logit regression model and estimated propensity scores. Second, we used an inverse probability weighted regression adjustment approach to determine cost-saving OAC options. We also examined component-specific costs (i.e., drug, hospitalization, emergency department and physician) to understand the drivers of cost-saving OACs. We found that compared to warfarin, rivaroxaban and apixaban treatments were cost-saving options, with per-patient 1-year healthcare cost savings at $2436 and $1764, respectively. These savings were driven by cost-savings in hospitalization, emergency department visits, and physician visits, outweighing higher drug costs. These results were robust to alternative model specifications and estimation procedures. Treating AF patients with rivaroxaban and apixaban than warfarin reduces healthcare costs. OAC reimbursement policies for AF patients should consider rivaroxaban or apixaban over warfarin as the first-line treatment.

Medium-Term Outcomes of the Different Antithrombotic Regimens After Transcatheter Aortic Valve Implantation

Bioprosthetic valve thrombosis is associated with accelerated bioprosthesis degeneration and valve re-replacement. Whether 3-month warfarin use after transcatheter aortic valve implantation (TAVI) protects against such consequences is unknown. We aimed to investigate if 3-month warfarin treatment after TAVI is associated with better outcomes than dual antiplatelet therapy (DAPT) and single antiplatelet therapy (SAPT) at medium-term follow-up. Adults who underwent TAVI were identified retrospectively (n = 1,501) and classified into warfarin, DAPT, and SAPT groups based on antithrombotic regimen received. Patients with atrial fibrillation were excluded. Outcomes and valve hemodynamics were compared between the groups. Annualized change from baseline in mean gradients and effective orifice area at last follow-up echocardiography was calculated. Overall, 844 patients were included (mean age: 80 ± 9 years, 43% women; 633 receiving warfarin, 164 DAPT, and 47 SAPT). Median time to follow-up was 2.5 (interquartile range 1.2 to 3.9) years. There were no differences in the adjusted outcome end points of ischemic stroke, death, valve re-replacement/intervention, structural valve degeneration, or their composite end point at follow-up. Annualized change in aortic valve area was significantly higher in DAPT (−0.11 [0.19] cm2/year) than warfarin (−0.06 [0.25] cm2/y, p = 0.03), but annualized change in mean gradients was not different (p >0.05). In conclusion, antithrombotic regimen, including warfarin, after TAVI was associated with marginally lower decrease in aortic valve area but no difference in medium-term clinical outcomes compared with DAPT and SAPT. Bioprosthetic valve thrombosis is associated with accelerated bioprosthesis degeneration and valve re-replacement. Whether 3-month warfarin use after transcatheter aortic valve implantation (TAVI) protects against such consequences is unknown. We aimed to investigate if 3-month warfarin treatment after TAVI is associated with better outcomes than dual antiplatelet therapy (DAPT) and single antiplatelet therapy (SAPT) at medium-term follow-up. Adults who underwent TAVI were identified retrospectively (n = 1,501) and classified into warfarin, DAPT, and SAPT groups based on antithrombotic regimen received. Patients with atrial fibrillation were excluded. Outcomes and valve hemodynamics were compared between the groups. Annualized change from baseline in mean gradients and effective orifice area at last follow-up echocardiography was calculated. Overall, 844 patients were included (mean age: 80 ± 9 years, 43% women; 633 receiving warfarin, 164 DAPT, and 47 SAPT). Median time to follow-up was 2.5 (interquartile range 1.2 to 3.9) years. There were no differences in the adjusted outcome end points of ischemic stroke, death, valve re-replacement/intervention, structural valve degeneration, or their composite end point at follow-up. Annualized change in aortic valve area was significantly higher in DAPT (−0.11 [0.19] cm2/year) than warfarin (−0.06 [0.25] cm2/y, p = 0.03), but annualized change in mean gradients was not different (p >0.05). In conclusion, antithrombotic regimen, including warfarin, after TAVI was associated with marginally lower decrease in aortic valve area but no difference in medium-term clinical outcomes compared with DAPT and SAPT.

Drug interactions between ALK inhibitors and warfarin with concurrent use of bucolome: a case report

BackgroundAlectinib, crizotinib, and ceritinib, are anaplastic lymphoma kinase-tyrosine kinase inhibitors (ALK-TKIs) that exhibit high protein binding, and their metabolism is associated with the cytochrome P450 (CYP) isoenzymes 2C9 or 3A4. The plasma protein binding rate of warfarin, which is used to prevent and treat venous thromboembolism, is also high. Warfarin is a racemate of S-warfarin and R-warfarin, which are metabolized by CYP2C9 and CYP3A4, respectively. Reports on the drug interactions between each of the above-mentioned ALK-TKIs and warfarin with concurrent use of bucolome are currently lacking.Case presentation.We report a case of a patient receiving warfarin and bucolome, whose international normalized ratio (INR) increased after sequential treatment with alectinib, crizotinib, and ceritinib. The patient was a 61-year-old man with a history of aortic valve regurgitation, who was receiving warfarin treatment following aortic valve replacement. Bucolome, which can enhance the effect of warfarin, was also used simultaneously. The patient was diagnosed with primary lung adenocarcinoma, and ALK rearrangement was detected during second-line chemotherapy. After progression of the disease with chemotherapy, sequential treatment with alectinib, crizotinib, and ceritinib was initiated. Pretreatment INR values were in the therapeutic range (target INR of 2–3) but increased to supratherapeutic levels each time after initiation of alectinib, crizotinib, or ceritinib treatment. Adjustment of warfarin dose or discontinuation of bucolome were necessary to maintain the therapeutic INR range. There were no serious bleeding events or substantial changes in dietary intake.Displacement of plasma protein binding or competitive inhibition of metabolism by alectinib, crizotinib, and ceritinib could increase the plasma concentration of the unbound form of warfarin, resulting in high INR values. In addition, alectinib, crizotinib, and ceritinib might cause displacement of bucolome from plasma proteins, followed by displacement of warfarin or inhibition of warfarin metabolism caused by the unbound form of bucolome.ConclusionsClose monitoring of INR and adjustment of warfarin dosage are needed during treatment with alectinib, crizotinib, or ceritinib in patients who receive warfarin with concurrent use of bucolome.

Trajectories of adherence to extended treatment with warfarin and risks of recurrent venous thromboembolism and major bleeding

BackgroundLittle is published about warfarin therapy adherence patterns beyond 6 months of initial anticoagulant treatment and their association with effectiveness and safety for patients with venous thromboembolism (VTE). ObjectivesTo compare the risks of recurrent VTE and major bleeding during extended treatment between adherence patterns using MarketScan Commercial and Medicare Supplemental databases (2013-2019). MethodsIn a retrospective cohort study, we included patients with incident VTE who completed an initial 6-month anticoagulant treatment and received either warfarin or no extended therapy. Group-based trajectory models were used to identify distinct extended treatment trajectories. Associations between the trajectories and risk of hospitalization due to recurrent VTE and major bleeding were assessed using inverse probability treatment-weighted Cox proportional hazards models. ResultsCompared with no extended treatment, consistently high warfarin adherence was associated with a significantly decreased risk of hospitalization due to recurrent VTE (hazard ratio [HR] = 0.23; 95% CI, 0.12-0.45), but gradually (HR = 0.29; 95CI, 0.08-1.06) or rapidly declining (HR = 0.14; 95% CI, 0.02-1.24) adherence showed no association with the risk of hospitalization due to recurrent VTE. Compared with no extended treatment, warfarin extended therapy was associated with an increased risk of hospitalization due to major bleeding regardless of adherence patterns (consistently high: HR = 2.08; 95% CI, 1.18-3.64, gradually declining: HR = 2.10; 95% CI, 0.74-5.95, and rapidly declining: HR = 9.19; 95% CI, 4.38-19.29). However, compared with rapidly declining adherence, consistently high (HR = 0.23; 95% CI, 0.11-0.47) and gradually declining (HR = 0.23; 95% CI, 0.08-0.64) adherence were associated with decreased risk of hospitalization due to major bleeding. ConclusionThe findings indicated that consistently high adherence to extended warfarin treatment was associated with a decreased risk of hospitalization due to recurrent VTE but an increased risk of hospitalization due to major bleeding compared with no extended treatment.

Comparison of the real-life clinical outcomes of warfarin with effective time in therapeutic range and non-vitamin K antagonist oral anticoagulants: Insight from the AFTER-2 trial.

It is unclear whether warfarin treatment with high time in therapeutic range (TTR) is as effective and safe as non-vitamin K antagonist oral anticoagulants (NOACs). It is crucial to compare warfarin with effective TTR and NOACs to predict long-term adverse events in patients with atrial fibrillation. We aimed to compare the long-term follow-up results of patients with atrial fibrillation (AF) who use vitamin K antagonists (VKAs) with effective TTR and NOACs. A total of 1140 patients were followed at 35 different centers for five years. During the follow-up period, the international normalized ratio (INR) values were studied at least 4 times a year, and the TTR values were calculated according to the Roosendaal method. The effective TTR level was accepted as >60% as recommended by the guidelines. There were 254 patients in the effective TTR group and 886 patients in the NOAC group. Ischemic cerebrovascular disease/transient ischemic attack (CVD/TIA), intracranial bleeding, and mortality were considered primary endpoints based on one-year and five-year follow-ups. Ischemic CVD/TIA (3.9% vs. 6.2%; P = 0.17) and intracranial bleeding (0.4% vs. 0.5%; P = 0.69), the one-year mortality rate (7.1% vs. 8.1%; P = 0.59), the five-year mortality rate (24% vs. 26.3%; P = 0.46) were not different between the effective TTR and NOACs groups during the follow-up, respectively. The CHA2DS2-VASC score was similar between the warfarin with effective TTR group and the NOAC group (3 [2-4] vs. 3 [2-4]; P = 0.17, respectively). Additionally, survival free-time did not differ between the warfarin with effective TTR group and each NOAC in the Kaplan-Meier analysis (dabigatran; P = 0.59, rivaroxaban; P = 0.34, apixaban; P = 0.26, and edoxaban; P = 0.14). There was no significant difference in primary outcomes between the effective TTR and NOAC groups in AF patients.

Impacts of Diabetes Mellitus on Cardiovascular Outcomes and Differential Effects of Direct Oral Anticoagulants in Patients with Left Ventricular Thrombus.

The focus of this investigation into the impact of type 2 diabetes mellitus (T2DM) on left ventricular thrombus (LVT) is (a) the differences in LVT characteristics, (b) long-term clinical outcomes, and (c) differential effects of direct oral anticoagulants (DOAC) among patients with T2DM and without diabetes. Patients with confirmed LVT from 2009 to 2021 were included. The primary endpoints were major adverse cardiac and cerebrovascular events (MACCE), composite of cardiovascular death, ischemic stroke, and acute myocardial infarction (AMI). The secondary endpoints were all-cause death and cardiovascular death. Multivariable competing-risk regression and cumulative incidence functions (CIF) were used to evaluate the adverse consequences. In total, 1675 patients were assessed initially. Follow-up data were available for 91.1% of the participants. Median follow-up was 3.8 years. This retrospective study ultimately comprised 1068 participants, of which 429 had T2DM. Significantly higher proportions of comorbidities were observed in the T2DM group. The location, morphology, and size of LVT were similar in the two groups. Multivariable analysis suggested a higher risk of MACCE among patients with T2DM. The difference in risk between the two groups after matching and weighting was not statistically significant. Among the whole sample (n = 638) or the just the non-diabetic patients with LVT and anticoagulation (n = 382), the incidence of MACCE did not differ between DOAC treatment and warfarin treatment. In the diabetic LVT population with anticoagulation (n = 256), DOAC treatment was associated with a significantly higher risk of MACCE than was warfarin treatment. The location and morphology of LVT are similar in T2DM and non-diabetic patients. A higher risk of MACCE was found among patients with diabetes.

Mortaliteyle Sonuçlanan Geç Başlangıçlı Warfarin Kaynaklı Cilt Nekrozu Olgusu

Warfarin-induced skin necrosis is a rare complication of warfarin therapy and is associated with high mortality. Here, we present a case of warfarin-induced skin necrosis, that was fatal in a 53-year-old female patient who was started on warfarin treatment 5.5 years ago due to atrial fibrillation and previous mitral valve surgery. Patients using warfarin should be evaluated for warfarin-induced skin necrosis when they present with skin lesions. Early diagnosis, early discontinuation of the drug, early initiation of supportive treatment can be life-saving.