International Normalized Ratio Levels Research Articles

Outcomes of patients with acute severe autoimmune hepatitis: Predictors of non-response to corticosteroids and need for liver transplantation.

Acute severe autoimmune hepatitis (AS-AIH) is an evolving concept and the outcomes and optimal treatment have been less studied. In this study, we aimed to investigate the outcomes of patients with AS-AIH and predictors of non-response to corticosteroid therapy and need for liver transplantation. In a retrospective cohort, we included patients with AS-AIH admitted to our liver center. We defined AS-AIH based on the international autoimmune hepatitis group score as acute presentation of AIH with an international normalized ratio (INR)≥1.5 and without liver cirrhosis and hepatic encephalopathy. All patients received high dose corticosteroid therapy. Treatment response was defined as liver transplant free survival at 4months after presentation. Factors associated with response to corticosteroids and survival of patients were studied. In total, 61 patients with AS-AIH were included. Forty-seven patients responded to corticosteroid therapy. In the multivariate regression model, baseline INR (odds ratio [OR]: 0.184; 95% confidence interval [CI]: 0.048-0.699; p=0.013) and delayed versus early initiation of corticosteroid (after vs. before 5days of presentation) (OR: 0.189; 95% CI: 0.039-0.919; p=0.039) were independent predictors of clinical non-response to corticosteroid therapy. In the multivariable Cox regression model, baseline INR level (OR: 2.542; 95% CI: 1.188-5.440; p=0.016) and delayed initiation of corticosteroids (OR: 3.578; 95% CI: 1.084-11.812; p=0.036) were independent predictors of liver transplant free survival at 6months after diagnosis. Delayed initiation of corticosteroid therapy might be predictive of clinical non-response to medical therapy and need for liver transplantation in patients with AS-AIH.

A retrospective cohort analysis of factors associated with the development of refeeding syndrome in children 0–59 months diagnosed with severe acute malnutrition in a South African setting

BackgroundRefeeding syndrome (RFS) is a life-threatening, underdiagnosed, and under-researched complication in treating children with severe acute malnutrition (SAM). This study aimed to determine the incidence and onset of RFS and identify biochemical abnormalities, clinical signs, and complications associated with RFS development in children, 0–59 months, treated with SAM in a South African public hospital setting. MethodsA retrospective cohort study was performed on hospital medical records of children aged 0–59 months, diagnosed with SAM at Rahima Moosa Mother and Child Hospital, Johannesburg, from 1/10/2014 to 31/12/2018. The onset of RFS among children included in the study was diagnosed based on published criteria for RFS. On admission, children who developed RFS and those who did not were compared concerning biochemistry and clinical signs and symptoms. ResultsA total of 148 medical records were retrieved from the hospital archives. The diagnosis of SAM based on the World Health Organization (WHO) definition was confirmed in 126 children who were then included in the study. The median age of the 126 children (63 % male) with confirmed SAM was 11.2 months (P25:7.0 months; P75:17.0 months). The in-hospital mortality rate was 18.2 %, of which 8.7 % were retrospectively diagnosed as having developed RFS during their recorded hospital stay, despite implementing the WHO treatment guidelines for SAM. A significantly higher percentage of the children who developed RFS presented on admission with hypophosphatemia (p = 0.015), hypokalemia (p = 0.001), hyponatremia (p = 0.001), an international normalized ratio (INR) of above 1.7 (p = 0.025), diarrhea (p = 0.042), dehydration (p = 0.029) and urinary tract infection (UTI) (p = 0.041), than those who did not. Children who developed RFS stayed in hospital significantly longer than those who did not (18 vs. 12 days with a p-value of 0.003). ConclusionIn this population of children with SAM treated in a South African public hospital setting, the presence on hospital admission of low levels of electrolytes, elevated INR, dehydration, diarrhea, and UTI was significantly associated with developing RFS. Recognizing these as possible red flags for developing RFS in children admitted with SAM might contribute to improved outcomes and needs further investigation.

The Relationship Between Preoperative International Normalized Ratio and Postoperative Major Bleeding in Total Shoulder Arthroplasty.

This study aimed to assess the relationship between preoperative international normalized ratio (INR) levels and major postoperative bleeding events after total shoulder arthroplasty (TSA). The American College of Surgeons National Surgical Quality Improvement Program database was queried for TSA from 2011 to 2020. A final cohort of 2405 patients with INR within 2 days of surgery were included. Patients were stratified into four groups: INR ≤ 1.0, 1.0 < INR ≤ 1.25, 1.25< INR ≤ 1.5, and INR > 1.5. The primary outcome was bleeding requiring transfusion within 72 hours, and secondary outcome variables included complication, revision surgery, readmission, and hospital stay duration. Multivariable logistic and linear regression analyses adjusted for relevant comorbidities were done. Of the 2,405 patients, 48% had INR ≤ 1.0, 44% had INR > 1.0 to 1.25, 7% had INR > 1.25 to 1.5, and 1% had INR > 1.5. In the adjusted model, 1.0 < INR ≤ 1.25 (OR 1.7, 95% CI 1.176 to 2.459), 1.25 < INR ≤ 1.5 (OR 2.508, 95% CI 1.454 to 4.325), and INR > 1.5 (OR 3.200, 95% CI 1.233 to 8.302) were associated with higher risks of bleeding compared with INR ≤ 1.0. The risks of thromboembolism and bleeding lie along a continuum, with higher preoperative INR levels conferring higher postoperative bleeding risks after TSA. Clinicians should use a patient-centered, multidisciplinary approach to balance competing risks.

Factors influencing voriconazole plasma level in intensive care patients.

In clinical routine, voriconazole plasma trough levels (Cmin) out of target range are often observed with little knowledge about predisposing influences. To determine the distribution and influencing factors on voriconazole blood levels of patients treated on intensive- or intermediate care units (ICU/IMC). Data were collected retrospectively from patients with at least one voriconazole trough plasma level on ICU/IMC (n = 153) to determine the proportion of sub-, supra- or therapeutic plasma levels. Ordinal logistic regression analysis was used to assess factors hindering patients to reach voriconazole target range. Of 153 patients, only 71 (46%) reached the target range at the first therapeutic drug monitoring, whereas 66 (43%) patients experienced too-low and 16 (10%) too-high plasma levels. Ordinal logistic regression analysis identified the use of extra corporeal membrane oxygenation (ECMO), low international normalized ratio (INR) and aspartate-aminotransferase (AST) serum levels as predictors for too-low plasma levels. Our data highlight an association of ECMO, INR and AST levels with voriconazole plasma levels, which should be considered in the care of critically ill patients to optimize antifungal therapy with voriconazole.

The Utilisation of INR to identify coagulopathy in burn patients.

Studies conflict on the significance of burn-induced coagulopathy. We posit that burn-induced coagulopathy is associated with injury severity in burns. Our purpose was to characterize coagulopathy profiles in burns and determine relationships between % total burn surface area (TBSA) burned and coagulopathy using the International Normalized Ratio (INR). Burned patients with INR values were identified in the TriNetX database and analyzed by %TBSA burned. Patients with history of transfusions, chronic hepatic failure, and those on anticoagulant medications were excluded. Interquartile ranges for INR in the burned study population were 1.2 (1.0-1.4). An INR of ≥ 1.5 was used to represent those with burn-induced coagulopathy as it fell outside the 3rd quartile. The population was stratified into subgroups using INR levels <1.5 or ≥1.5 on the day of injury. Data are average ± SD analyzed using chi-square; p < .05 was considered significant. There were 7,364 burned patients identified with INR <1.5, and 635 had INR ≥1.5. Comparing TBSA burned groups, burn-induced coagulopathy significantly increased in those with ≥20% TBSA; p = .048 at 20-29% TBSA, p = .0005 at 30-39% TBSA, and p < .0001 for 40% TBSA and above. Age played a significant factor with average age for those with burn-induced coagulopathy 59 ± 21.5 years and 46 ± 21.8 for those without (p < .0001). After matching for age, TBSA, and demographics, the risk of 28 day-mortality was higher in those with burn-induced coagulopathy compared to those without (risk difference 20.9%, p < .0001) and the odd ratio with 95% CI is 4.45 (3.399-5.825). Investigation of conditions associated with burn-induced coagulopathy showed the effect of heart diseases to be significant; 53% of patients with burn-induced coagulopathy had hypertension (p < .0001). Burn-induced coagulopathy increases with %TBSA burned. The information gained firmly reflects a link between %TBSA and burn-induced coagulopathy, which could be useful in prognosis and treatment decisions.

Clinical and virological profile of locally acquired acute hepatitis E in South Bulgaria.

Acute hepatitis E virus (HEV) infection is recognized as a zoonosis in several European countries. We describe the characteristics and outcomes of locally acquired acute HEV hepatitis. A prospective study was conducted among adult patients with acute HEV hepatitis at the University Hospital in Plovdiv, South Bulgaria between January 2020 and May 2022. An acute HEV infection case was a patient with acute hepatitis and laboratory-confirmed anti-HEV IgM antibodies and/or HEV RNA in serum. Demographic data, clinical manifestations, laboratory test results, and outcomes were recorded. A total of 46 patients were selected. Median age of 65 years (interquartile range [IQR] 50.8-74.3). 28 (60.87%) were male. 22 (47.83%) had comorbidities such as diabetes (15), liver cirrhosis (3), hepatitis B virus infection (2), and malignancies (2). Of the 46, 18 (39.13%) patients were viremic and, HEV genotype 3 was detected. The median (IQR) serum alanine aminotransferase, aspartate aminotransferase, bilirubin, platelet, and international normalized ratio levels were 992 (495.8-1714.3) U/L, 715 (262.5-1259.3) U/L, 204 (132.3-235.5) µmol/L, 204 (132.3-235.5) ×109 L, and 1.0 (0.89-1.19), respectively. Six patients with underlying liver diseases had severe hepatitis. A young patient with osteoarthritis progressed to acute liver failure and died. The persistent HEV infection was ruled out in 2 malignant patients who tested HEV RNA negative three months after discharge. Acute HEV hepatitis is a diagnosis to consider after excluding other causes of acute viral hepatitis. A diagnostic workup should include timely testing for HEV to identify the most vulnerable to severe consequences.

Prognostic value of coagulation markers in patients with colorectal caner: A prospective study.

The occurrence, growth, and metastasis of colorectal cancer (CRC) are connected to the hypercoagulable state of blood (CRC). This study aimed to identify significant coagulation factors to predict metastasis and prognosis of CRC. Thrombomodulin (TM), thrombin-antithrombin complex (TAT), α2-plasmininhibitor-plasmin complex (PIC), and tissue plasminogen activator-inhibitor complex (t-PAIC) were detected by chemiluminescence immunoassay using Sysmex HISCL5000 automated analyzers. The Sysmex CS 5100 automatic blood coagulation analyzer was used to detect d-dimer (DD), fibrin degradation product (FDP), prothrombin time (PT), thrombin time (TT), international normalized ratio (INR), fibrinogen (Fbg), and activated partial thromboplastin time (APTT). Area under the curve (AUC) and the receiver operating characteristic curve (ROC) were used to assess the diagnostic efficacy of markers. Kaplan-Meier analysis was used to calculate survival probabilities. Independent prognostic factors and the nomogram were developed using single-factor and multifactor cox regression analysis model. The following indicators (TM, TAT, PIC, t-PAIC, DD, FDP, PT, INR, APTT, and Fbg) were markedly higher in CRC patients than in healthy controls, and they were higher in the metastasis (M) group than in the nonmetastasis (NM) group. The combination "TAT + PIC + DD + FDP + Fbg" can distinguish M from NM with exceptional sensitivity and specificity. Patients with CRC who had high levels of TAT, PIC, DD, FDP, Fbg, TM, tPAIC, PT, and INR had significantly shorter survival. The prognosis of CRC patients can be predicted by coagulation indicators. The independent predictive variables for overall survival were found to be TM and DD. To forecast CRC patient survival, a nomogram was created.

Comprehensive Management of Anticoagulants Induced Decompensated Severe Anemia in Postmitral Valve Replacement

Abstract Mechanical prosthetic valve needs consideration for anticoagulation. The objective of this case report was to know how maintenance of oral anticoagulant therapy is very important in patients, especially with mechanical heart valve replacement. It is the holistic management of mitral valve replacement (MVR) patients with high international normalized ratio (INR) (&gt;100), which led bleeding into the peritoneal cavity and causes decompensated severe anemia. Although it is a rare presentation for a patient of MVR with high INR level but which is most commonly presented for cerebrovascular accident. Anemia is a thoughtful worldwide problem that disturbs the quality of life in persons of all ages. A 28-year-old Indian woman with follow-up case of post-MVR came to the hospital with complaints of breathing difficulty, altered sensorium, pulse rate of 150–170 bpm (beats/min) irregularly irregular, blood pressure (80/50 mmHg), palpitation, and abdominal pain. Blood test report revealed her hemoglobin (Hb) was 3.2 g%, suggestive of severe anemia, INR was &gt;100 s. Hence, patient diagnosed as follow-up case of MVR (#27 mm mechanical bileaflet mitral valve prosthesis) with peritoneal bleeding, an oral anticoagulant with decompensated severe anemia managment should be done. Ended the progression of her hospitalization, she received four units of packed red blood cell transfusions; Vitamin K was given intravenous once daily for 2 days and no anticoagulant was given, so far, INR was high with serial monitoring of INR and Hb. Her symptoms of breathing difficulty, pain in abdomen, weakness and giddiness resolute by the finish of her hospital stay, and she recompensed to her oral anticoagulant therapy with improved Hb and hemodynamics. Disapprovingly high INR levels are classically related with bleeding disorders revealed on imperative indicators and hemodynamic variability. To our understanding, one of the lowermost noted Hb is because of bleeding due to very high INR, so monitoring of therapeutic INR level with anticoagulants is very-very important.

Turkish Real Life Atrial Fibrillation in Clinical Practice: TRAFFIC Study.

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia worldwide and is associated with an increased risk of thromboembolism, ischemic stroke, impaired quality of life, and mortality. The latest research that shows the prevalence and incidence of AF patients in Türkiye was the Turkish Adults' Heart Disease and Risk Factors study, which included 3,450 patients and collected data until 2006/07.The Turkish Real Life Atrial Fibrillation in Clinical Practice (TRAFFIC) study is planned to present current prevalence data, reveal the reflection of new treatment and risk approaches in our country, and develop new prediction models in terms of outcomes. The TRAFFIC study is a national, prospective, multicenter, observational registry. The study aims to collect data from at least 1900 patients diagnosed with atrial fibrillation, with the participation of 40 centers from Türkiye. The following data will be collected from patients: baseline demographic characteristics, medical history, vital signs, symptoms of AF, ECG and echocardiographic findings, CHADS2-VASC2 and HAS-BLED (1-year risk of major bleeding) risk scores, interventional treatments, antithrombotic and antiarrhythmic medications, or other medications used by the patients. For patients who use warfarin, international normalized ratio levels will be monitored. Follow-up data will be collected at 6, 12, 18, and 24 months. Primary endpoints are defined as systemic embolism or major safety endpoints (major bleeding, clinically relevant nonmajor bleeding, and minor bleeding as defined by the International Society on Thrombosis and Hemostasis). The main secondary endpoints include major adverse cardiovascular events (systemic embolism, myocardial infarction, and cardiovascular death), all-cause mortality, and hospitalizations due to all causes or specific reasons. The results of the 12-month follow-up of the study are planned to be shared by the end of 2023. The TRAFFIC study will reveal the prevalence and incidence, demographic characteristics, and risk profiles of AF patients in Türkiye. Additionally, it will provide insights into how current treatments are reflected in this population. Furthermore, risk prediction modeling and risk scoring can be conducted for patients with AF.

Changes in TNF-α, IL-33, and MIP-1α before and after artificial liver support treatment and their prognostic value.

To investigate the effect of ALST (artificial liver support treatment) on inflammatory factors and prognosis in patients with ACLF (acute-on-chronic liver failure). Data of ACLF patients admitted to the No. 2 People's Hospital of Lanzhou from June 2020 to January 2023 were retrospectively analyzed. Patients were compared before and after ALST in terms of ALT (Alanine Aminotransferase), AST (Aspartate Aminotransferase), TBil (Total Bilirubin), Cr (Creatinine), INR (International Normalized Ratio), MELD (Model for End-Stage Liver Disease) scores, as well as TNF-α (Tumor Necrosis Factor-α), IL-33 (Interleukin-33), and MIP-1α (Macrophage Inflammatory Protein-1 α) levels. The ROC (receiver operating characteristic) curve was used to analyze the efficacy of the above indicators in predicting 90-day mortality in patients. After the treatment, the levels of ALT, AST, TBil, Cr, INR, and MELD score were significantly lower than those before treatment (all P<0.001). Also, the levels of TNF-α, IL-33, and MIP-1α were substantially lower than those before treatment (all P<0.001). TNF-α, IL-33, and MIP-1α were positively correlated with MELD score before and after the treatment (all P<0.01). TNF-α, IL-33, MIP-1α, and MELD score were significantly higher in the death group than in the survival group (all P<0.01). The ROC curves showed that MELD (AUC=0.857), TNF-α (AUC=0.836), IL-33 (AUC=0.749), and MIP-1α (AUC=0.746) had high efficacy in predicting patients' 90-day mortality. ALST can significantly reduce TNF-α, IL-33, and MIP-1α levels in patients with ACLF, and postoperative TNF-α, IL-33, and MIP-1α levels have a high predictive value for patients' prognosis.

Safety Issues of Herb-Warfarin Interactions.

Warfarin is a popular anticoagulant with high global demand. However, studies have underlined serious safety issues when warfarin is consumed concomitantly with herbs or its formulations. This review aimed to highlight the mechanisms behind herb-warfarin interactions while laying special emphasis on its PKPD interactions and evidence on Herb-Warfarin Interaction (HWI) with regards to three different scenarios, such as when warfarin is consumed with herbs taken as foods or prescribed as medicine, or when used in special situations. A targeted literature methodology involving different scientific databases was adopted for acquiring information on the subject of HWIs. Results of the present study revealed some of the fatal consequences of HWI, including post-operative bleeding, thrombosis, subarachnoid hemorrhage, and subdural hematomas occurring as a result of interactions between warfarin and herbs or commonly associated food products from Hypericum perforatum, Zingiber officinale, Vaccinium oxycoccos, Citrus paradisi, and Punica granatum. In terms of PK-PD parameters, herbs, such as Coptis chinensis Franch. and Phellodendron amurense Rupr., were found to compete with warfarin for binding with plasma proteins, leading to an increase in free warfarin levels in the bloodstream, resulting in its augmented antithrombic effect. Besides, HWIs were also found to decrease International Normalised Ratio (INR) levels following the consumption of Persea americana or avocado. Therefore, there is an urgent need for an up-to-date interaction database to educate patients and healthcare providers on these interactions, besides promoting the adoption of novel technologies, such as natural language processing, by healthcare professionals to guide them in making informed decisions to avoid HWIs.

Optimal INR Level in Nonvalvular Atrial Fibrillation Patients in Thailand: A Multi-Site Study

Background: Warfarin is a common drug for thromboembolic prevention in patients with nonvalvular atrial fibrillation (NVAF). However, hemorrhagic complications are also a concern. The optimal international normalized ratio (INR) level is different in each ethnicity. Objective: To establish the INR range with lowest all adverse event, optimal INR, in Thai NVAF patients from large data, nationwide Warfarin Registry Network (WaRN). Materials and Methods: The present study was a retrospective cohort study. It analyzed the data of 31,704 Thai NVAF patient between January 1, 2010 and December 31, 2020. The numbers of thromboembolic and bleeding events were correlated to INR level at the time of event. The six groups of INR range were defined as less than 1.5, 1.5 to 1.9, 2.0 to 2.5, 2.6 to 3.0, 3.1 to 3.5, and greater than 3.5. Results: The data from 797 warfarin clinics were analyzed with an observation period of 21,328.52 patient-years. The median duration of follow-up was 519 days (IQR 172, 1,183). Of the 31,407 patients, 277 patients experienced 319 thromboembolic events, and 3,398 patients experienced 4,860 bleeding events. The thromboembolic events were 4.92, 1.89, 0.86, 0.72, 0.39, 0.36 per 100 patient-years in INR range of less than 1.5, 1.5 to 1.9, 2.0 to 2.5, 2.6 to 3.0, 3.1 to 3.5, and more than 3.5, respectively. The bleeding events were 12.69, 9.51, 8.41, 15.35, 36.38, 125.03 per 100 patient-years in INR range of less than 1.5, 1.5 to 1.9, 2.0 to 2.5, 2.6 to 3.0, 3.1 to 3.5, and more than 3.5, respectively. The all-adverse events were 17.61, 11.40, 9.27, 16.07, 36.77, 125.39 per 100 patient-years in the INR range of less than 1.5, 1.5 to 1.9, 2.0 to 2.5, 2.6 to 3.0, 3.1 to 3.5, and more than 3.5, respectively. Conclusion: The incidence density of all-adverse events was lowest in INR range of 2.0 to 2.5. This range should be the optimal therapeutic INR level for Thai NVAF patient. However, the INR range can extend to 1.5 to 2.5 in clinical practice. Keywords: Optimal INR; Nonvalvular Atrial Fibrillation, Bleeding, Thromboembolism

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.

Utilization of International Normalized Ratio-Derived Formula to Predict Plasma Rivaroxaban Level - Validation Study and Real-World Experience

Introduction: Specific assay of plasma rivaroxaban level are not always readily available with short turn-around-time which hampered the management of urgent clinical situations. The response of routine coagulation screening tests show huge lot-to-lot differences with the plasma rivaroxaban level. International normalized ratio (INR) is a standardized measurement taking into account of lot-to-lot variations of PT reagents. In this study, we aimed to build a predictive formula of plasma rivaroxaban levels from INR value and validated in real world clinical situations. Method: The study period was 1 st January 2018 to 31 st December 2021. Ninety-four patients who taking rivaroxaban participated in the study. Patients were randomized into testing cohort and validation cohorts. The prediction formula was built from the testing cohort and then validated in validation cohort. The predictive performance was further validated on real-world clinical requests. Results: The baseline characteristics of both cohorts were well-balance. There was significant correlation between the plasma rivaroxaban level and PT in both the testing and validation cohorts (Testing cohort: R square 0.838, p &amp;lt; 0.01; Validation cohort: R square 0.836, p &amp;lt; 0.01). The plasma rivaroxaban level showed significant correlation with APTT in both the testing and validation cohorts (Testing cohort: R square 0.744, p &amp;lt; 0.01; Validation cohort: R square 0.654, p &amp;lt; 0.01). There was also significant correlation between INR and plasma rivaroxaban levels in both the testing and validation cohorts (Testing cohort: R square 0.819, p &amp;lt;0.01; Validation cohort: R square 0.816, p &amp;lt; 0.01). Both INR and plasma rivaroxaban levels were undergone natural logarithmic transformation. We choose the quadratic model to determine the relationship between the natural log of plasma rivaroxaban level and the natural log of INR as it had highest R square value (R square 0.850, p&amp;lt;0.01). The formula is: ln (plasma rivaroxaban level) = 2.96+7.87 X ln (INR) - 5.04X (ln (INR))^2. The root mean square error (RMSE) of the predictive formula for the testing and validation cohorts were 61.81 ng/ml and 69.32 ng/ml, respectively. We received a total of 43 requests for plasma rivaroxaban assay involved 29 patients during the study period (Table 1). Three patients had multiple requests for plasma DOAC level assays during this period. The cut-off INR value was 1.3 for administration of antidote for rivaroxaban, which corresponded to a rivaroxaban level of 75 ng/ml. The sensitivity and specificity for using this INR cut-off value to determine the threshold plasma rivaroxaban level (75 ng/ml) for administration of reversal agents were 95% (95%CI: 85.4 -100%) and 87.5% (95%CI:71.3-100%) respectively in real world clinical situations (Table 2). Conclusion: Plasma rivaroxaban level can be calculated from prediction formula by INR value with satisfactory accuracy and the INR cut-off value derived from it can be used to guide the decision for administration of reversal agents with excellent sensitivity and specificity.

The Concordance between Laboratory and POCT INR and the Value of Bedside Measurement of INR in Patients on Warfarin Undergoing Dental Procedures: A Prospective Cohort Study

Introduction: Patients on anticoagulation particularly warfarin suffers when they have a dental problem that requires intervention. Most of dentists worry and refuse to perform procedures on patients on warfarin because of the risk of bleeding and request the availability of international normalized ratio (INR) results before procedure which can delay the procedure and add another burden on the patient particularly who live away from the treating center. Objective: To evaluate the efficacy and the value of using point of care testing (POCT) (INR) in patients on warfarin undergoing dental procedures. We also had analyzed the frequency and severity of dental bleeding in patients on warfarin therapy and the concordance between Laboratory based INR and POCT INR. This is the first interim analysis on ongoing prospective study. Methods: A cohort study of 30 patients on chronic use of anticoagulation therapy with warfarin for different clinical indications who planned to undergo dental procedures at a teaching hospital in Saudi Arabia. The patients' demographic and clinical characteristics, type and severity of bleeding, and INR measured by both HemoChrone (POCT) and prothrombin time (PT) were performed at same time. Descriptive statistics, paired samples statistics, correlations, and analysis of variance (ANOVA) were performed. Results: The sample consisted of 60% females, with a mean age of 49.9 (SD 13.3) years. The most common indications for warfarin therapy were mechanical aortic valve replacement (56.7%), atrial fibrillation (13.3%), and atrial flutter (16.7%). Before the procedure, the mean Laboratory INR was 2.6 (SD 0.6) and the mean HemoChrone POCT INR was 2.8 (SD 0.8). There was a significant positive correlation between the two methods (r = 0.81, p &amp;lt; 0.001). There was no significant difference in the INR and type of bleeding, dentist performed the procedure, or dose of warfarin. There was no correlation between the Bleeding severity or type and the INR level in patients undergoing different dental procedures. Even among those with HemoChrone POCT INR &amp;gt; 3, which is considered high and increases the risk of bleeding, there was no significant correlation with bleeding. Conclusion: These results imply that warfarin therapy can be safely continued for most dental procedures without increasing the risk of bleeding regardless of the INR results. The HemoChrone POCT INR is a dependable and practical method to monitor the effect of warfarin in dental settings which can reassure the dentists before procedure. Figure 1: The concordance between Laboratory and POCT INR

Multichannel resonant acoustic rheometry system for quantification of coagulation of multiple human plasma samples

Resonant Acoustic Rheometry (RAR), a newly developed ultrasound-based technique for non-contact characterization of soft viscoelastic materials, has shown promise for quantitative viscoelastic assessment of temporally changing soft biomaterials in real time, and may be used to monitor blood coagulation process. Here, we report the development of a novel, multichannel RAR (mRAR) system for simultaneous measurements of multiple temporally evolving samples and demonstration of its use for monitoring the coagulation of multiple small-volume plasma samples. The mRAR system was constructed using an array of 4 custom-designed ultrasound transducers at 5.0 MHz and a novel electronic driving system that controlled the generation of synchronized ultrasound pulses for real time assessment of multiple samples simultaneously. As a proof-of-concept of the operation of the mRAR system, we performed tests using pooled normal human plasma samples and anti-coagulated plasma samples from patients treated with warfarin with a range of International Normalized Ratio (INR) values as well-characterized samples with different coagulation kinetics. Our results show that simultaneous tracking of dynamic changes in 4 plasma samples triggered by either kaolin or tissue factor was achieved for the entire duration of coagulation. The mRAR system captured distinct changes in the samples and identified parameters including the clotting start time and parameters associated with the stiffness of the final clots that were consistent with INR levels. Data from this study demonstrate the feasibility of the mRAR system for efficient characterization of the kinetic coagulation processes of multiple plasma samples.

Mortality on extracorporeal membrane oxygenation: Evaluation of independent risk factors and causes of death during venoarterial and venovenous support.

Most patients on extracorporeal membrane oxygenation (ECMO) decease during therapy on the system. However, the actual causes of death have not been studied sufficiently. This study analyses the etiology, prevalence, and risk factors for the outcome variable death during ongoing ECMO for all patients and divided according to venoarterial (VA) or venovenous (VV) support. We retrospectively analysed all patients receiving ECMO support at our institution between March 2006 to January 2021. Only the patients deceased during ongoing support were included. 2016 patients were placed on VA (n = 1168; 58%) or VV (n = 848; 42%) ECMO; 759 patients (37.7%) deceased on support. The causes of death differed between the support types: VA ECMO patients mostly died from cerebral ischemia (34%), low-cardiac output (LCO; 24.1%) and multi-organ failure (MOF; 21.6%), whereas in VV ECMO cases, refractory respiratory failure (28.2%), and sepsis (20.4%) dominated. Multivariate regression analysis revealed cardiopulmonary resuscitation (CPR) and acidosis prior to ECMO as risk factors for dying on VA ECMO, while high inotropic doses pre-ECMO, a high fraction of inspired oxygen on day 1, elevated lactate dehydrogenase, and international normalized ratio levels lead to an unfavourable outcome in VV ECMO patients. Even in highly experienced centers, ECMO mortality remains high and occurs mainly on support or 24h after its termination. The causes of death differ between VV and VA ECMO, depending on the underlying diseases responsible for the need of extracorporeal support.

Abstract 17496: Exploring the Benefits: Role of Repeat Transesophageal Echocardiography (TEE) in Patients Anticoagulated for Four Weeks

Background: A left atrial appendage (LAA) thrombus is a well-known complication of atrial fibrillation (AF). Vitamin K antagonists (VKAs) have been well studied been considered the gold standard for thromboembolic prophylaxis. We present a case of LAA thrombus despite compliance with VKAs. Clinical presentation: A 70-year-old female with atrial fibrillation and diabetes presented with left-sided weakness and left facial droop, CT head showed right middle cerebral artery infarct. Vitals were unremarkable. Electrocardiogram showed AF with a rapid ventricular response. She was on warfarin with the most recent international normalized ratio level of 2.3. Transthoracic echocardiography revealed an ejection fraction of 55%, severe left ventricular hypertrophy, and severely dilated left atrium (LA) with LA diameter of 5.3 cm (&gt;= 4.7 cm in women indicates severe dilatation). Transesophageal echocardiography (TEE) with bubble study demonstrated a large thrombus in the LAA with evidence of patent foramen ovale. The pulse wave Doppler (PWD) of the LAA on TEE also showed an LAA velocity of &lt;20 cm/sec, which indicated that there was the highest probability that the thrombus was forming within LAA. Hypercoagulability work-up for thrombosis while on Coumadin such as anti-B2 glycoprotein, anticardiolipin, and factor V Leiden mutation were negative. The patient was started on enoxaparin with appropriate follow-up upon discharge. Discussion: The prevalence of LAA thrombus in patients with AF receiving a minimum of 3 weeks of anticoagulation, was approximately 3%. The presence of a LAA thrombus is a known contraindication to cardioversion and catheter ablation in patients with AF as it can result in cardioembolic stroke. However, current guidelines for cardioversion do not recommend pre-procedural TEE in patients undergoing cardioversion for AF if they have been on therapeutic oral anticoagulation for at least 3 weeks while TEE use remains variable before catheter ablation.

Foldable low-cost point-of-care device for testing blood coagulation using smartphones

Cardiovascular diseases (CVDs) caused by thrombotic events are a significant global health concern, affecting millions of people worldwide. The international normalized ratio (INR) is the most widely used measure of coagulation status, and frequent testing is required to adjust blood-thinning drug dosage, requiring hospital visits and experts to perform the test. Here we present a low-cost and portable smartphone-based device for screening INR levels from whole blood samples at the point of care. Our device uses a 3D printed platform and light-emitting diode backlight modules to create a uniform optical environment, and its foldable design allows for easy transport. Our device also features an algorithm that allows users to acquire and process video of sample flow in a microfluidic channel on their smartphone, providing a cost-effective and convenient option for blood coagulation monitoring at the point of care. We tested the performance of our smartphone-based INR device using both commercially available control samples and clinical human blood samples, demonstrating high accuracy and reliability. Our device has the potential to improve patient outcomes by enabling more frequent monitoring and, as appropriate, dosage adjustments of blood-thinning drugs, providing an affordable and portable option for screening INR levels at the point of care.

The Effect of Molecular Adsorbent Recirculating System in Patients With Liver Failure: A Case Series of 44 Patients

Liver failure is associated with a high mortality rate, with many patients requiring transplant for definitive treatment. The Molecular Adsorbent Recirculating System (MARS) is a nonbiologic system that provides extracorporeal support.Literature on MARS therapy is mixed: outcomes support MARS therapy for patients with isolated acute liver failure, but data on patients with chronic disease is varied. Several case studies report success using MARS as a bridging treatment for patients awaiting transplant. The purpose of this case series is to present the outcomes of 44 patients who underwent MARS therapy forliver failure, 19 of whom used MARS therapy as a bridging therapy to transplant. This study retrospectively identified 44 patients who underwent MARS therapy for liver failure at Mayo Clinic, Jacksonville, between January 2014 and April 2021. Variables of interest included changes in laboratory markers of hepatic functioning, number and length of MARS therapy sessions, transplantation status, and mortality. Following MARS therapy, there were improvements in mean serum bilirubin, ammonia, urea, creatinine, International Normalized Ratio, alanine aminotransferase, and aspartate aminotransferase levels. Twenty-seven patients (61.36%) survived the hospital stay; 17 (38.63%) died in the hospital. The majority of surviving patients (n = 19; 73.07%) receivedliver transplant. Six did not require transplant (22.22%). All but 1 patient who received MARS as a bridging treatment to transplant survived the follow-up period (n = 18; 94.74%). Outcomes of these 44 cases suggest that MARS improves liver failure-associated laboratory parameters and may be effective therapy as a bridge to liver transplant.