Warfarin Woes: A Rare Case of Hemoperitoneum with Intramural Small Bowel Hematoma.

BACKGROUND Small bowel hematoma is a rare yet clinically significant condition characterized by the accumulation of blood within the mucosa and submucosa layers of the small intestine wall. It can lead to complications such as bowel obstruction, ischemia, perforation, and even hemorrhagic shock. The etiology of intramural small bowel hematoma is diverse, encompassing factors such as anticoagulant therapy, coagulopathies, vascular disorders, trauma, and underlying systemic conditions. CASE REPORT We present the case of a 67-year-old man with a history of aortic valve replacement who presented with intense abdominal pain. Physical examination revealed generalized abdominal tenderness and black stools upon rectal examination. Laboratory tests indicated coagulopathy with a prolonged thrombin time. A computed tomography scan confirmed the presence of an intramural small bowel hematoma and hemoperitoneum. The patient's condition significantly improved within 48 h under conservative management, including nasogastric tube insertion, continuous monitoring of gastric aspirate, nil per os status, intravenous fluids, and analgesics. Warfarin was temporarily stopped, and fresh frozen plasma was administered for anticoagulation reversal. Heparin infusion was initiated once the INR became within the therapeutic level. CONCLUSIONS The occurrence of spontaneous intramural small bowel hematoma, although rare, demands rapid diagnosis and prompt, well-coordinated management. This case underscores the pivotal role of multidisciplinary collaboration in providing a comprehensive assessment and a tailored approach to treatment. While conservative measures, including careful monitoring and supportive care, have demonstrated favorable outcomes, the consideration of surgical intervention remains crucial, particularly in severe cases.

[Perioperative management for fracture in a child with homozygous congenital protein C deficiency].

Congenital protein C (PC) deficiency is one type of hereditary thrombosis. Patients with hereditary thrombosis are at high risk for thrombosis in the perioperative period, but a standard management strategy has not been established. Here we report a case of perioperative management of a fracture in a child with homozygous congenital PC deficiency. The patient was a 3-year-old boy who was diagnosed with congenital PC deficiency at birth. He sustained a traumatic supracondylar fracture of the right humerus and underwent emergency surgery. To prepare for open surgery for fixation of the fracture, warfarin was discontinued, and an activated PC (APC) concentrate was used in combination with vitamin K antagonism. However, warfarin was administered during the scheduled nail extraction because the operation was minimally invasive. No thrombotic or bleeding complications occurred in either operation. In emergency surgery in patients with congenital PC deficiency, the combination of vitamin K and APC concentrate is considered a maintenance option for PC deficiency. Postoperative PT-INR control was difficult in our patient due to the administration of vitamin K and withdrawal of warfarin, and this issue must be addressed in the future. Further case experience is desirable to standardize perioperative management.

Potential Drug-Nutrient Interactions of 45 Vitamins, Minerals, Trace Elements, and Associated Dietary Compounds with Acetylsalicylic Acid and Warfarin-A Review of the Literature.

In cardiology, acetylsalicylic acid (ASA) and warfarin are among the most commonly used prophylactic therapies against thromboembolic events. Drug-drug interactions are generally well-known. Less known are the drug-nutrient interactions (DNIs), impeding drug absorption and altering micronutritional status. ASA and warfarin might influence the micronutritional status of patients through different mechanisms such as binding or modification of binding properties of ligands, absorption, transport, cellular use or concentration, or excretion. Our article reviews the drug-nutrient interactions that alter micronutritional status. Some of these mechanisms could be investigated with the aim to potentiate the drug effects. DNIs are seen occasionally in ASA and warfarin and could be managed through simple strategies such as risk stratification of DNIs on an individual patient basis; micronutritional status assessment as part of the medical history; extensive use of the drug-interaction probability scale to reference little-known interactions, and application of a personal, predictive, and preventive medical model using omics.

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.

Warfarin induced spontaneous gastric intramural haematoma presenting with palpitations.

Spontaneous gastric intramural haematoma is an uncommon complication associated with anticoagulant therapy. A patient receiving chronic warfarin for paroxysmal atrial fibrillation was admitted due to atrial fibrillation with rapid ventricular response (RVR). An incidental intra-abdominal mass was detected on a CT scan. Following the initiation of the amiodarone infusion, the patient experienced bleeding attributed to warfarin-amiodarone-induced coagulopathy, with no identifiable bleeding source. Subsequent CT scans revealed an enlargement of the intra-abdominal mass, suggesting gastric intramural haematoma. After coagulopathy reversal, the haematoma is managed conservatively. Our case underscores the potential for incidental bleeding even when the international normalised ratio is within the normal range in patients on chronic warfarin therapy. When managing such patients with atrial fibrillation with RVR, physicians should maintain a high index of suspicion for bleeding, emphasising the importance of prompt coagulopathy reversal.

Major bleeding in patients with atrial fibrillation treated with apixaban versus warfarin in combination with amiodarone: nationwide cohort study.

BACKGROUND: Amiodarone is an established treatment for atrial fibrillation (AF) but might interfere with the metabolism of apixaban or warfarin. Therefore, the aim was to investigate the occurrence of major bleeding among patients with AF treated with amiodarone in combination with apixaban or warfarin. METHODS: Retrospective observational study using Swedish health registers. All patients with AF in the National Patient Register and the National Dispensed Drug Register with concomitant use of amiodarone and warfarin or apixaban between 1 June 2013 and 31 December 2018 were included. Propensity score matching was performed, and matched cohorts were compared using Cox proportional HRs. The primary outcome was major bleeding resulting in hospitalisation based on International Classification of Diseases (ICD)-10 codes. Secondary outcomes included intracranial bleeding, gastrointestinal bleeding and other bleeding. Exploratory outcomes included ischaemic stroke/systemic embolism and all-cause/cardiovascular (CV) mortality. RESULTS: A total of 12 103 patients met the inclusion criteria and 8686 patients were included after propensity score matching. Rates of major bleeding were similar in the apixaban (4.3/100 patient-years) and warfarin cohort (4.5/100 patient-years) (HR: 1.03; 95% CI: 0.76 to 1.39) during median follow-up of 4.4 months. Similar findings were observed for secondary outcomes including gastrointestinal bleeding and other bleeding, and exploratory outcomes including ischaemic stroke/systemic embolism and all-cause/CV mortality. CONCLUSIONS: Among patients treated with amiodarone in combination with apixaban or warfarin, major bleeding and thromboembolic events were rare and with no significant difference between the treatment groups. EUPAS REGISTRY NUMBER: EUPAS43681.

Spinal subdural haemorrhage secondary to strenuous exercise and warfarin, complicated by acute ischaemic stroke.

Spinal subdural haemorrhage or haematoma (SSDH) is a rare condition that is often overlooked and missed on initial presentation due to its non-specific features that may mimic other more common pathologies. It is associated with high morbidity and mortality rates, with few evidence-based management principles, particularly during the subacute stages of recovery. In this report, we detail a case of SSDH associated with exercise and anticoagulation therapy, which was complicated by acute ischaemic stroke. SSDH should be suspected in cases of acute back pain without a clear alternative cause, particularly in coagulopathic individuals. Following treatment, early recommencement of anticoagulation therapy may be justified in certain cases where indicated, after careful consideration of the affected individual's risk profile.

Being precise with anticoagulation to reduce adverse drug reactions: are we there yet?

Anticoagulants are potent therapeutics widely used in medical and surgical settings, and the amount spent on anticoagulation is rising. Although warfarin remains a widely prescribed oral anticoagulant, prescriptions of direct oral anticoagulants (DOACs) have increased rapidly. Heparin-based parenteral anticoagulants include both unfractionated and low molecular weight heparins (LMWHs). In clinical practice, anticoagulants are generally well tolerated, although interindividual variability in response is apparent. This variability in anticoagulant response can lead to serious incident thrombosis, haemorrhage and off-target adverse reactions such as heparin-induced thrombocytopaenia (HIT). This review seeks to highlight the genetic, environmental and clinical factors associated with variability in anticoagulant response, and review the current evidence base for tailoring the drug, dose, and/or monitoring decisions to identified patient subgroups to improve anticoagulant safety. Areas that would benefit from further research are also identified. Validated variants in VKORC1, CYP2C9 and CYP4F2 constitute biomarkers for differential warfarin response and genotype-informed warfarin dosing has been shown to reduce adverse clinical events. Polymorphisms in CES1 appear relevant to dabigatran exposure but the genetic studies focusing on clinical outcomes such as bleeding are sparse. The influence of body weight on LMWH response merits further attention, as does the relationship between anti-Xa levels and clinical outcomes. Ultimately, safe and effective anticoagulation requires both a deeper parsing of factors contributing to variable response, and further prospective studies to determine optimal therapeutic strategies in identified higher risk subgroups.

Repeated Measurement of the Novel Atrial Biomarker BMP10 (Bone Morphogenetic Protein 10) Refines Risk Stratification in Anticoagulated Patients With Atrial Fibrillation: Insights From the ARISTOTLE Trial.

BACKGROUND: BMP10 (bone morphogenic protein 10) has emerged as a novel biomarker associated with the risk of ischemic stroke and other outcomes in patients with atrial fibrillation (AF). The study aimed to determine if repeated BMP10 measurements improve prognostication of cardiovascular events in patients with AF. METHODS AND RESULTS: BMP10 was measured using a prototype Elecsys immunoassay in plasma samples collected at randomization and after 2 months in patients with AF randomized to apixaban or warfarin in the ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) trial (n=2878). Adjusted Cox-regression models were used to evaluate the association between 2-month BMP10 levels and outcomes. BMP10 levels increased by 7.8% (P<0.001) over 2 months. The baseline variables most strongly associated with BMP10 levels at 2 months were baseline BMP10 levels, body mass index, sex, age, creatinine, diabetes, warfarin treatment, and AF-rhythm. During median 1.8 years follow-up, 34 ischemic strokes/systemic embolism, 155 deaths, and 99 heart failure hospitalizations occurred. Comparing the third with the first sample quartile, higher BMP10 levels at 2 months were associated with higher risk of ischemic stroke (hazard ratio [HR], 1.33 [95% CI, 0.67-2.63], P=0.037), heart failure (HR, 1.91 [95% CI, 1.17-3.12], P=0.012) and all-cause death (HR, 1.61 [95% CI, 1.17-2.21], P<0.001). Adding BMP10 levels at 2 months on top of established risk factors and baseline BMP10 levels improved the C-indices for ischemic stroke/systemic embolism (from 0.73 to 0.75), heart failure hospitalization (0.76-0.77), and all-cause mortality (0.70-0.72), all P<0.05. CONCLUSIONS: Elevated levels of BMP10 at 2 months strengthened the associations with the risk of ischemic stroke, hospitalization for heart failure, and all-cause mortality. Repeated measurements of BMP10 may further refine risk stratification in patients with AF.

Safflower yellow for injection enhances anti-coagulation of warfarin in rats: implications in pharmacodynamics and pharmacokinetics.

This study investigated whether Safflower Yellow for injection (SYI) would affect the anticoagulation of warfarin in rats.Wistar male rats were divided into six groups randomly and administered with SYI (9 mg/kg, intraperitoneal injection) in single-dose and steady-dose warfarin (0.2 mg/kg, oral gavage), respectively. The pharmacodynamic parameters of PT and APTT were measured by a coagulation analyser. R/S-warfarin concentration was measured by UHPLC-MS/MS, and pharmacokinetic parameters calculated using DAS 2.0 software.The single-dose study demonstrated that SYI, alone or co-administered with warfarin, could significantly increase PT, INR, and APTT values (p < 0.01). R-warfarin Cmax, AUC, and t1/2 values increased by 9.25% (p > 0.05), 25.96% (p < 0.01), and 26.17% (p < 0.01), respectively, whereas the CL/F value reduced by 22.22% (p < 0.01) in the presence of SYI. Meanwhile, S-warfarin Cmax, AUC, and t1/2 values increased by 37.41%, 32.11%, and 31.73% (all p < 0.01), respectively, whereas the CL/F value reduced by 33.33% (p < 0.01). The steady-dose study showed that PT, INR, APTT, and the concentrations of R/S-warfarin increased significantly when SYI was co-administered with warfarin (p < 0.01).SYI can enhance warfarin's anticoagulation intensity and decelerate its metabolism in rats.

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.

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

BACKGROUND: Hemorrhage represents the most common and serious side effect of antithrombotic agents. Many studies have compared the risk of bleeding between different antithrombotic agents, but analysis of time-to-onset for hemorrhage induced by these drugs is yet sparse. METHODS: We conducted a retrospective study based on the adverse drug reaction reports on antithrombotic agents collected by the Henan Adverse Drug Reaction Monitoring Center. We assessed the reporting odds ratio to determine the disproportionate reporting signals for bleeding and the Weibull shape parameter was used to evaluate the time-to-onset data. RESULTS: In the signal detection, crude low molecular weight heparin-hemorrhage was found as a positive signal. The hemorrhage for most antithrombotic agents was random failure profiles. In particular, the hazard of hemorrhage decreased over time for warfarin and clopidogrel and increased for alteplase, nadroparin, and dipyridamole. CONCLUSION: We found that the risk of bleeding in patients taking Crude low molecular weight heparins was significantly higher compared to other antithrombotic agents, but with a small magnificence, which may be attributed to the severely irrational use of this medication under improper management. Statistics in days, results showed that the risk of bleeding decreased over time for warfarin and clopidogrel and increased for alteplase, nadroparin, and dipyridamole.

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.

Initiation patterns of anticoagulants for atrial fibrillation among older UK adults with and without chronic kidney disease, 2010-2020.

BACKGROUND: There is a paucity of data on the initiation patterns of anticoagulants among older atrial fibrillation patients with and without chronic kidney disease (CKD). SETTING AND METHODS: We used the UK Clinical Practice Research Datalink (2010-2020) to conduct a retrospective cohort study to evaluate anticoagulant initiation patterns for older adults (≥65 years) with CKD (N=18 421) and without CKD (N=41 901), categorised by severity of CKD: stages 3a, 3b and 4, and initiation dose by respective direct oral anticoagulant (DOAC). RESULTS: Over the study period, warfarin initiations sharply declined and were replaced by DOACs regardless of CKD status or stage. By 2020, patients with CKD were modestly more likely (8.8% difference) to initiate apixaban compared with those without CKD (58.8% vs 50.0%; p<0.01). Among patients with CKD, those with stages 3a and 3b CKD had higher apixaban initiations compared with stage 4 CKD (56.9% and 64.6% vs 52.9%, respectively; p<0.01). Conversely, patients with stage 4 CKD were over three times more likely to initiate warfarin (14.7%) compared with those with stage 3a (2.6%) and 3b (4.0%) CKD (p<0.01). Throughout the study period, there was a rise in the proportion of patients initiating the higher 10 mg daily dose for apixaban, with an increase of 20.6% (from 64.3% in 2013 to 84.9% in 2020; p value for trend <0.01) among patients without CKD, and 21.8% (53.1% to 74.9%; p<0.01), 24.4% (18.8% to 43.2%; p<0.01) and 18.5% (0.0% to 18.2%; p<0.01) among patients with stages 3a, 3b and 4 CKD, respectively. CONCLUSIONS AND RELEVANCE: Initiation of DOACs increased regardless of CKD status and stage, although with a reduced magnitude in severe CKD. Apixaban emerged as the preferred agent, with a secular trend towards the higher initiation dose in all subgroups. These findings illuminate evolving trends and priorities in anticoagulant preferences among patients with and without CKD.

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.

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.