Evaluating the Effect of Timing on Point-of-Care Testing of INR

Objectives: To evaluate if there is a difference in International Normalized Ratio (INR) readings taken within the 15 second time frame after lancing the finger vs 30-60 seconds of obtaining a blood drop utilizing a CoaguChek® XS Plus point-of-care (POC) INR machine in patients on warfarin therapy. Methods: All adult patients on anticoagulation therapy with warfarin who were managed in a pharmacist-run anticoagulation clinic were considered for inclusion in the study. The mean difference of INR readings taken less than 15 seconds vs between 30-60 seconds after the blood drop was obtained from the finger was assessed. Results: A total of 62 pairs of INR results were included in the study. There was a mean difference in INR of .076 (95% CI 0.011-.140; P = .0217) when comparing INR readings taken less than 15 seconds and between 30-60 seconds after the blood drop was obtained from the finger. Conclusions: There was a significant difference in INR readings taken less than 15 seconds vs 30-60 seconds after obtaining the blood drop when utilizing a POC INR machine. INR readings taken 30-60 seconds after obtaining a blood drop with the CoaguChek® XS Plus POC INR machine is not acceptable for use to monitor patients on warfarin.

4-Factor Prothrombin Complex Concentrate Dosing Strategies: A Retrospective Evaluation

ObjectivesDetermine indication specific 4-Factor prothrombin complex concentrate (4FPCC) dosing strategies within a hospital system and subsequent effectiveness. Background: 4FPCC is FDA approved for reversal of vitamin K antagonists (VKA) for acute major bleeding or need for urgent surgery/invasive procedure. Since its approval, off label use has expanded to include direct oral anticoagulant reversal and perioperative hemostasis. Optimal dosing strategies remain controversial, and recent studies have evaluated fixed-dose regimens with lower doses than those recommended in product labeling. Methods/Materials: Retrospective cohort with manual chart review for patients who received 4FPCC spanning 2 years. Primary outcome was to characterize dosing. Secondary outcomes were INR normalization, hemostatic efficacy, in-hospital mortality, and renal function change. Results: Of the 300 patients evaluated, 80% received 4FPCC for anticoagulant reversal, with 66% of those for VKA and 34% for DOAC. The remaining 20% received 4FPCC for a non-reversal indication. Of the patients requiring anticoagulation reversal, 25% received doses lower than recommended and 6% received higher. 71% of patients received 4FPCC for life-threatening bleed, and 45% of them had intracranial hemorrhage. Higher mortality with higher than recommended doses was the only statistically significant secondary outcome (P = .018). Conclusion: We found that lower doses than recommended were used in a significant number of patients. The higher than recommended doses group constituted a small proportion of patients and the higher mortality was attributed to patient acuity on presentation. Additional studies evaluating dosing approach are required to determine lowest effective dosing for various indications.

Telemedicine-based medical care compared to in-person medical care for warfarin follow-up: A retrospective propensity score matching cohort study

PURPOSE

Telemedicine is underutilized in Saudi Arabia, which is a matter of concern, especially since previous literature has showed its equivalence with office visits in providing access to care and convenience for patients while reducing anticoagulation-related bleeding events when appropriate measures are followed. The purpose of this study is to analyze the efficacy of telehealth-based care compared to in-person visit care for warfarin follow-up.

METHODS

The authors conducted a retrospective chart review comparing the mean percentage of time in the therapeutic range (TTR) of international normalized ratio (INR) values among patients prescribed warfarin from July 2019 to November 2020 at King Faisal Specialist Hospital & Research Center - Jeddah Branch whose anticoagulant therapy was managed via telemedicine or through in-person clinic visits. A subcohort analysis of outcomes in the telemedicine and in-person groups was performed using propensity score matching, and descriptive analysis was done for the entire cohort.

RESULTS

A total of 350 patient records were included in this retrospective study. Matched analysis for 148 patients using propensity score matching showed that the mean (SD) percentages of TTR were 62.82% (19.46%) and 70.61% (19.83%) in the telemedicine and in-person groups, respectively (P = 0.017). There was no statistical difference in the incidence of major or minor bleeding events, thromboembolic events, and hospital readmission between the two groups.

CONCLUSION

The study results showed that patients on oral anticoagulation therapy managed through a telemedicine method had a lower overall TTR percentage than a matched group of patients managed through in-person anticoagulant clinic visits, thus demonstrating that using a telemedicine approach alone for warfarin follow-up may not help patients to maintain their INR target level.

The effect of COVID-19 vaccination on anticoagulation stability in adolescents and young adults using vitamin K antagonists

INTRODUCTION

The European Medicine Agency has authorized COVID-19 vaccination in adolescents and young adults (AYAs) from 12 years onwards. In elderly vitamin K antagonist (VKA) users, COVID-19 vaccination has been associated with an increased risk of supra- and subtherapeutic INRs. Whether this association is also observed in AYAs using VKA is unknown. Our aim was to describe the stability of anticoagulation after COVID-19 vaccination in AYA VKA users.

MATERIALS AND METHODS

A case-crossover study was performed in a cohort of AYAs (12-30 years) using VKAs. The most recent INR results before vaccination, the reference period, were compared with the most recent INR after the first and, if applicable, second vaccination. Several sensitivity analyses were performed in which we restricted our analysis to stable patients and patients without interacting events.

RESULTS

101 AYAs were included, with a median age [IQR] of 25 [7] years, of whom 51.5 % were male and 68.3 % used acenocoumarol. We observed a decrease of 20.8 % in INRs within range after the first vaccination, due to an increase of 16.8 % in supratherapeutic INRs. These results were verified in our sensitivity analyses. No differences were observed after the second vaccination compared to before and after the first vaccination. Complications after vaccination occurred less often than before vaccination (9.0 vs 3.0 bleedings) and were non-severe.

CONCLUSIONS

the stability of anticoagulation after COVID-19 vaccination was decreased in AYA VKA users. However, the decrease might not be clinically relevant as no increase of complications nor significant dose adjustments were observed.

Quality of Anticoagulation With Phenprocoumon and Warfarin in Left Ventricular Assist Device Patients: A Multicenter Study

VISUAL ABSTRACT

of key results. INR, international normalized ratio; TTR, time in therapeutic range; PTR, percentage of tests in range; HRAE, hemocompatibility-related adverse event; FFUV, first follow-up visit; GIB, gastrointestinal bleeding; HR, hazard ratio.http://links.lww.com/ASAIO/A961.

Decentralization and Virtualization of INR-based Anticoagulation Control During the COVID-19 Pandemic

OBJECTIVE

To investigate the effectiveness of the decentralization and virtualization of anticoagulation clinics just before and during the coronavirus disease 2019 (COVID-19) pandemic.

METHODS

We conducted a cohort study investigation at Prince Sultan Cardiac Clinics PSCC Qassim region, Saudi Arabia. To evaluate the effectiveness of the virtual coagulation clinic, we calculated the time in therapeutic range (TTR), Morisky score for adherence, and satisfaction. Demographics of the patients were analyzed to group patients based on their regions or districts to facilitate the visits. Thirteen different PHCs/Hospitals were allocated for decentralization based on patient density in that region. Intensive courses were provided for all general practitioners (GPs) regarding warfarin anticoagulation and point of care testing (POCT) using iSTAT. All appointments were scheduled by WhatsApp, with no more actual visits to the main center.

RESULTS

Among the included participants (n = 5616), 61.1% were females, 38.9% were males, and the mean age was 60.5 (18-85) years. The total number of clinic visits was 7303 per month, with an average of 1.3 visits per patient. Approximately 95% of the participants had a valvular indication to receive anticoagulation; of them, 55% underwent mitral valve replacement. Moreover, after the virtualization of the INR clinic, keeping INR levels within a therapeutic range was reported in 80% of patients. Regarding patient satisfaction, 90% of the total population was satisfied by the new experience.

CONCLUSION

Decentralization and virtualization of the INR clinic have similar TTR results if conducted properly.

Reliability of International Normalized Ratio Results in the CoaguChek Pro II System in a Clinical Setting

The National Institute of Cardiology has previously used the CoaguChek® XS Plus system (Roche Diagnostics International Ltd), comparing capillary blood prothrombin time/international normalized ratio (PT/INR) results with those obtained using BCS-XP/Thromborel (Siemens). We assessed the reliability of PT/INR results using the third-generation CoaguChek Pro II system, the CoaguChek XS Plus system, and cobas® t 411 for citrated plasma analysis. Venous and capillary PT/INR were measured (N = 204). Spearman's correlation, Bland-Altman, and concordance analysis between methods were conducted. Spearman's correlation coefficients between venous/capillary INR were high for CoaguChek Pro II versus CoaguChek XS Plus (r = 0.994), CoaguChek Pro II versus cobas t 411 (r = 0.967), and CoaguChek XS Plus versus cobas t 411 (r = 0.968). Good concordance was observed among capillary methods (concordance coefficient [κ] = 0.888) and remaining relationships (P < .001 for all): cobas t 411 versus CoaguChek XS Plus (κ = 0.696) and cobas t 411 versus CoaguChek Pro II (κ = 0.684). In conclusion, good agreement was observed between CoaguChek Pro II, CoaguChek XS Plus, and cobas t 411.

Improved Time in Therapeutic Range with International Normalized Ratio Remote Monitoring for Patients with Left Ventricular Assist Devices

Despite advances in therapy, bleeding and thromboembolic events are frequent complications in patients with left ventricular assist device (LVAD) support. Maintaining warfarin in therapeutic range has been shown to be more challenging in this patient population compared to other indications. Patients with LVADs on warfarin typically are within goal international normalized ratio (INR) range 36-57% of the time, compared to about 65% for other indications. The goal of this study was to evaluate if an INR remote monitoring system along with the implementation of a standardized warfarin management protocol improves warfarin time in therapeutic range (TTR) for patients with LVADs. This single-center, retrospective, observational study included 78 patients with LVADs that were followed at our academic center from January 2015 to October 2017. In October 2016, we updated our warfarin management protocol and implemented a remote monitoring system with patients' weekly INR results monitored. The primary objective of the study was to determine the difference between TTRs in remote monitoring versus standard monitoring. We found that the average TTR was significantly higher in the remote monitoring group compared to the standard monitoring cohort (61.1% vs. 40.0%, p < 0.005). However, bleeding, thrombotic incidence, and hospital readmission rates were similar between the two patient cohorts. Remote monitoring improved warfarin TTR significantly in this study and may have the potential to improve anticoagulation-related outcomes in patients with LVADs.

Using a Simple Prescription Gap to Determine Warfarin Discontinuation Can Lead to Substantial Misclassification

BACKGROUND

Warfarin remains widely used and a key comparator in studies of other direct oral anticoagulants. As longer-than-needed warfarin prescriptions are often provided to allow for dosing adjustments according to international normalized ratios (INRs), the common practice of using a short allowable gap between dispensings to define warfarin discontinuation may lead to substantial misclassification of warfarin exposure. We aimed to quantify such misclassification and determine the optimal algorithm to define warfarin discontinuation.

METHODS

We linked Medicare claims data from 2007 to 2014 with a multicenter electronic health records system. The study cohort comprised patients ≥65 years with atrial fibrillation and venous thromboembolism initiating warfarin. We compared results when defining warfarin discontinuation by (1) different gaps (3, 7, 14, 30, and 60 days) between dispensings and (2) having a gap ≤60 days or bridging larger gaps if there was INR ordering at least every 42 days (60_INR). Discontinuation was considered misclassified if there was an INR ≥2 within 7 days after the discontinuation date.

RESULTS

Among 3,229 patients, a shorter gap resulted in a shorter mean follow-up time (82, 95, 117, 159, 196, and 259 days for gaps of 3, 7, 14, 30, 60, and 60_INR, respectively; p < 0.001). Incorporating INR (60_INR) can reduce misclassification of warfarin discontinuation from 68 to 4% (p < 0.001). The on-treatment risk estimation of clinical endpoints varied significantly by discontinuation definitions.

CONCLUSION

Using a short gap between warfarin dispensings to define discontinuation may lead to substantial misclassification, which can be improved by incorporating intervening INR codes.

Polymethyl Methacrylate-Based Smart Microfluidic Point-of-Care Testing of Prothrombin Time and International Normalized Ratio through Optical Detection

The mechanical heart valve is a crucial solution for many patients. However, it cannot function on the state of blood as human tissue valves. Thus, people with mechanical valves are put under anticoagulant therapy. A good measurement of the state of blood and how long it takes blood to form clots is the prothrombin time (PT); moreover, it is an indicator of how well the anticoagulant therapy is, and of whether the response of the patient to the drug is as needed. For a more specific standardized measurement of coagulation time, an international normalized ratio (INR) is established. Clinical testing of INR and PT is relatively easy. However, it requires the patient to visit the clinic for evaluation purposes. Many techniques are therefore being developed to provide PT and INR self-testing devices. Unfortunately, those solutions are either inaccurate, complex, or expensive. The present work approaches the design of an anticoagulation self-monitoring device that is easy to use, accurate, and relatively inexpensive. Hence, a two-channel polymethyl methacrylate-based microfluidic point-of-care (POC) smart device has been developed. The Arduino based lab-on-a-chip device applies optical properties to a small amount of blood. The achieved accuracy is 96.7%.

INR and COVID-19 severity and mortality: A systematic review with meta-analysis and meta-regression

Objectives

D-dimer elevations, suggesting a pro-thrombotic state and coagulopathy, predict adverse outcomes in coronavirus disease 2019 (COVID-19). However, the clinical significance of other coagulation markers, particularly the international normalized ratio (INR), is not well established. We conducted a systematic review and meta-analysis of the INR in COVID-19.

Methods

A literature search was conducted in PubMed, Web of Science and Scopus, between January 2020 and February 2021, for studies reporting INR values, measures of COVID-19 severity, and mortality (PROSPERO registration number: CRD42021241468).

Results

Thirty-eight studies in 7440 COVID-19 patients with low disease severity or survivor status during follow up (50 ​% males, mean age 57 years) and 2331 with high severity or non-survivor status (60 ​% males, mean age 69 years) were identified. The INR was significantly prolonged in patients with severe disease or non-survivor status than in patients with mild disease or survivor status (standard mean difference, SMD, 0.60; 95 ​% confidence interval, CI 0.42 to 0.77; p ​< ​0.001). There was extreme between-study heterogeneity (I² ​= ​90.2 ​%; p ​< ​0.001). Sensitivity analysis, performed by sequentially removing each study and re-assessing the pooled estimates, showed that the magnitude and direction of the effect size was not modified. The Begg's and Egger's t-tests did not show publication bias. In meta-regression, the SMD of the INR was significantly associated with C-reactive protein (p ​= ​0.048) and D-dimer (p ​= ​0.001).

Conclusions

Prolonged INR values were significantly associated with COVID-19 severity and mortality. Both INR prolongation and D-dimer elevations can be useful in diagnosing COVID-19-associated coagulopathy and predicting clinical outcomes.

Examining therapeutic equivalence between branded and generic warfarin in Brazil: The WARFA crossover randomized controlled trial

OBJECTIVES

To determine whether the generic and branded warfarins used as anticoagulants in Brazil are therapeutic equivalents based on their international normalized ratio (INR) results.

METHODS

This crossover randomized controlled trial had four periods. We used the branded Marevan and two generic versions of warfarin sodium tablets, manufactured by União Química and Teuto laboratories, all purchased from retail drugstores. Eligible participants were outpatients from an anticoagulation clinic at a university hospital in São Paulo, Brazil. They had atrial fibrillation or flutter and had been using warfarin for at least 2 months with an INR therapeutic range of 2.0-3.0. Randomization was by numbered, opaque, sealed envelopes. Healthcare personnel and outcome assessors were blinded to treatments, but patients were not. The primary outcome was the variability in the INR (ΔINR) and secondary outcomes included mean INR. We accepted formulations as equivalent if the 95% confidence interval (CI) of the comparison of ΔINR between branded and generic formulations was within the limit of ±0.49.

RESULTS

One hundred patients were recruited and randomized to six sequences of treatment (four sequences with n = 17 and two sequences with n = 16). União Química generic warfarin had equivalent variability in the INR to Marevan (ΔINR +0.09 [95% CI -0.29 to +0.46], n = 84). Comparison between Teuto generic warfarin and Marevan was inconclusive (ΔINR +0.29 [95% CI -0.09 to +0.68], n = 84).

CONCLUSIONS

Marevan and União Química warfarin had equivalent therapeutic effectiveness and both could be confidently used for anticoagulation. The comparison between Marevan and TW was inconclusive and does not warrant a statement of equivalence. Our methods are especially important for comparing generic and branded drugs that raise concerns and may be subject of future investigations by regulatory agents.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02017197.

Is intravenous thrombolysis safe for acute ischemic stroke patients taking warfarin with INR 1.9?: A case report

INTRODUCTION

Intravenous thrombolysis is not suitable for patients undergoing oral anticoagulants therapy, with INR > 1.7 or PT > 15 s. We described a case of intravenous thrombolysis in a patient with INR 1.9.

PATIENT CONCERNS

A 66-year-old female patient was diagnosed with acute appendicitis complicated with atrial fibrillation. Seven days after admission, the patient suffered mixed aphasia with right limb asthenia. The NIHSS score was 11 points. and early infarction and hemorrhagic manifestations were not found in the emergency head CT. Thirty minutes after the onset of symptoms, NIHSS of patient increased from 11 to 14, but the INR was 1.92.

DIAGNOSIS

Acute ischemic stroke.

INTERVENTIONS

The IT therapy was recommended and all the therapy related risks were explained to the patient's parents. Briefly, the patient was given rTPA 38.5 mg. In addition to intravenous thrombolysis, VitK1 40 mg was simultaneously administered.

OUTCOME

The patient's symptoms of drowsiness were improved. After 24 hours, all symptoms were stabilized with NIHSS of 2 points, there was a slight language obstruction, and no hemorrhagic transformation in head CT. Three months later, the review showed MRS score of 0, and the patient could take care of herself in daily life.

CONCLUSION

The clinical guidelines are still the main reference for guiding clinical practice, and the main thrombolytic standards and contraindications for treatment still need to be conformed. On this basis, for individualized patients, clinicians must accurately judge the cause of acute stroke, to make optimal choice, reduce disability and mortality, and improve quality of life of patients.

Emergency medicine misconceptions: Utility of routine coagulation panels in the emergency department setting

BACKGROUND

Coagulation panels are ordered for a variety of conditions in the emergency department (ED).

OBJECTIVE

This narrative review evaluates specific conditions for which a coagulation panel is commonly ordered but has limited utility in medical decision-making.

DISCUSSION

Coagulation panels consist of partial thromboplastin time (PTT) or activated partial thromboplastin time (aPTT), prothrombin time (PT), and international normalized ratio (INR). These tests evaluate the coagulation pathway which leads to formation of a fibrin clot. The coagulation panel can monitor warfarin and heparin therapy, evaluate for vitamin K deficiency, evaluate for malnutrition or severe systemic disease, and assess hemostatic function in the setting of bleeding. The utility of coagulation testing in chest pain evaluation, routine perioperative assessment, prior to initiation of anticoagulation, and as screening for admitted patients is low, with little to no change in patient management based on results of these panels. Coagulation testing should be considered in systemically ill patients, those with a prior history of bleeding or family history of bleeding, patients on anticoagulation, or patients with active hemorrhage and signs of bleeding. Thromboelastography and rotational thromboelastometry offer more reliable measures of coagulation function.

CONCLUSIONS

Little utility for coagulation assessment is present for the evaluation of chest pain, routine perioperative assessment, initiation of anticoagulation, and screening for admitted patients. However, coagulation panel assessment should be considered in patients with hemorrhage, patients on anticoagulation, and personal history or family history of bleeding.

Quality of INR control and switching to non-Vitamin K oral anticoagulants between women and men with atrial fibrillation treated with Vitamin K Antagonists in Spain. A population-based, real-world study

Background

Worldwide, there is growing evidence that quality of international normalized ratio (INR) control in atrial fibrillation patients treated with Vitamin K Antagonists (VKA) is suboptimal. However, sex disparities in population-based real-world settings have been scarcely studied, as well as patterns of switching to second-line Non-VKA oral anticoagulants (NOAC). We aimed to assess the quality of INR control in atrial fibrillation patients treated with VKA in the region of Valencia, Spain, for the whole population and differencing by sex, and to identify factors associated with poor control. We also quantified switching to Non-VKA oral anticoagulants (NOAC) and we identified factors associated to switching.

Methods

This is a cross-sectional, population-based study. Information was obtained through linking different regional electronic databases. Outcome measures were Time in Therapeutic Range (TTR) and percentage of INR determinations in range (PINRR) in 2015, and percentage of switching to NOAC in 2016, for the whole population and stratified by sex.

Results

We included 22,629 patients, 50.4% were women. Mean TTR was 62.3% for women and 63.7% for men, and PINNR was 58.3% for women and 60.1% for men (p<0.001). Considering the TTR<65% threshold, 53% of women and 49.3% of men had poor anticoagulation control (p<0.001). Women, long-term users antiplatelet users, and patients with comorbidities, visits to Emergency Department and use of alcohol were more likely to present poor INR control. 5.4% of poorly controlled patients during 2015 switched to a NOAC throughout 2016, with no sex differences.

Conclusion

The quality of INR control of all AF patients treated with VKA in 2015 in our Southern European region was suboptimal, and women were at a higher risk of poor INR control. This reflects sex disparities in care, and programs for improving the quality of oral anticoagulation should incorporate the gender perspective. Clinical inertia may be lying behind the observed low rates of switching in patient with poor INR control.

Impact of pre-admission oral anticoagulation on ischaemic stroke volume, lesion pattern, and frequency of intracranial arterial occlusion in patients with atrial fibrillation

Aims

Therapeutic oral anticoagulation on hospital admission reduces morbidity and mortality after acute ischaemic stroke in patients with atrial fibrillation (AF). The underlying mechanism is not fully understood. In order to assess the impact of INR-level on admission on stroke volume, lesion pattern and the frequency of intracranial arterial occlusion, we analysed serial MRI measurements in AF patients suffering acute ischaemic stroke.

Methods and results

This subgroup analysis of the prospective '1000Plus' study included patients with acute ischaemic stroke and known AF or a first episode of AF in hospital. All patients underwent serial brain magnetic resonance imaging. Stroke patients were categorized as follows: Group1, phenprocoumon intake, international normalized ratio (INR) ≥1.7 on admission, no thrombolysis; Group2, INR < 1.7 on admission, thrombolysis; and Group3, INR < 1.7, no thrombolysis. In 98 AF patients {77 ± 9 years, 60% male; median National Institute of Health Stroke Scale [NIHSS] score on admission 5 (interquartile range [IQR] 2-8)} with known AF before admission, territorial infarction was less often found in Group 1 (n = 20) compared with Group 2 + 3 (20% vs. 47%, P = 0.022). Arterial occlusion rate on admission differed among groups (30%, 75%, and 35%, respectively, P = 0.004) but not between Group 1 vs. Group 2 + 3 (30% vs. 45%, P = 0.31). Median FLAIR volume on Days 5-7 was lower in Group1 compared with Group 2 (n = 20) [3.2 cm3 (IQR 1.1-11.3) vs. 18.6 cm3 (IQR 8.2-49.4); P = 0.009] but not compared with Group 2 + 3 [7.8 cm3 (IQR 1.6-25.9); P = 0.23]. An INR ≥ 1.7 on admission was not associated with smaller stroke volume in multivariable regression analysis. Adding 57 patients with a first AF episode during the in-hospital stay, similar results were observed in 155 AF patients.

Conclusion

In this AF cohort, an INR ≥ 1.7 at stroke onset affects lesion pattern but does not affect significantly lower stroke volume and the frequency of arterial occlusion on admission.

Thromboelastography Parameters in Patients with Acute on Chronic Liver Failure

INTRODUCTION AND AIM

Patients with acute on chronic liver failure (ACLF) have abnormal conventional coagulation tests- platelet count and international normalized ratio (INR). Thromboelastography (TEG) is a rapid, point-of-care assay, more comprehensive than platelet count and INR as it assesses for platelet adequacy (number and function), coagulation factors and clot retraction. The aim of the study was to evaluate the TEG parameters in patients with ACLF, chronic liver disease having acute decompensation (AD) and healthy subjects (HC).

MATERIAL AND METHODS

TEG parameters were assessed in patients with ACLF and AD within 24 h of admission. Consecutive patients were included in the study over 12 months. Healthy subjects were recruited as controls.

RESULTS

179 patients were included- 68 ACLF, 53 AD and 58 HC. The mean values of INR in ACLF, AD and HC groups were 2.9 ± 1.4, 1.6 ± 0.4 and 1.1 ± 0.2; P < 0.001. Among TEG parameters - maximum amplitude (MA) was low in ACLF and AD patients as compared with HC (53.8 ± 15, 58.3 ± 13.9 mm and 67.2 ± 12.1 mm, respectively; P < 0.001). Lysis at 30 min (LY30) was high in ACLF patients, as compared to AD and HC (8.6 ± 14.1%, 5.0 ± 9.5% and 4.9 ± 9.8%, respectively; P = 0.060). There were no differences in r time, k time, and alpha angle between groups; normal in >90% patients. There was no difference in TEG parameters between different ACLF grades, whereas CCTs were more deranged with increasing grades of ACLF.

CONCLUSION

Despite abnormal conventional coagulation tests, TEG parameters in ACLF patients are essentially normal, except reduced maximum amplitude. Future studies are needed to explore the utility of TEG in clinical management of ACLF patients.

Evaluation of quality of warfarin therapy by assessing patient's time in therapeutic range at a tertiary care hospital in Pakistan

OBJECTIVE

To assess the time in therapeutic range in patients on warfarin anti-coagulation therapy.

METHODS

The retrospective chart review was conducted at Aga Khan University Hospital, Karachi, and comprised data of patients having undergone anti-coagulation with warfarin from January 2013 to April 2015. To determine the mean time in therapeutic range, Rosendaal method was used. Association of time in therapeutic range with the composite outcome, bleeding and thromboembolic events was also assessed. Percentage of patients with time in therapeutic range <60% was calculated.

RESULTS

There were 92 patients whose median time in therapeutic range was 34.9% (interquartile range: 20.0- 55.7). Overall, 71(77.2%) patients had time in therapeutic range below 60% which had statistically significant correlation with the composite outcome (p<0.05). Number of comorbids was significant in predicting time in therapeutic range and patients with time in therapeutic range< 60% (p<0.05).

CONCLUSION

Subjects had poor anti-coagulation quality. It might be prudent to move towards novel oral anticoagulant drugsas the first choice for therapeutic anti-coagulation.

Time to therapeutic range (TtTR), anticoagulation control, and cardiovascular events in vitamin K antagonists-naive patients with atrial fibrillation

BACKGROUND

Vitamin K antagonists (VKAs) reduce cardiovascular events (CVEs) in atrial fibrillation (AF) when a time in therapeutic range (TiTR) >70% is achieved. Factors affecting the time to achieve the TR (TtTR) are unknown.

METHODS

Prospective observational study including 1,406 nonvalvular AF patients starting VKAs followed for a mean of 31.3months (3,690 patient/year); TiTR, TtTR, and SAMe-TT₂R₂ score were calculated, and CVEs were recorded.

RESULTS

Median TtTR was 8.0days (interquartile range 5.0-18.0). Patients with high TtTR (ie, >75th percentile) were more likely to be in AF than in sinus rhythm at entry (odds ratio [OR]: 1.423, P=.011). Median TiTR was 60.0%; low TiTR (below median) was associated with SAMe-TT₂R₂ score (OR: 1.175, P=.001), high TtTR (>75th percentile, OR: 1.357, P=.017), and number of international normalized ratio checks (OR: 0.998, P=.049). We recorded 113 CVEs (3.1%/y), with a higher rate seen in patients with TtTR >75th percentile compared to those below (log-rank test, P=.006). A multivariable Cox regression analysis showed that SAMe-TT₂R₂ score (hazard ratio [HR]: 1.331, P<.001), TtTR >75th percentile (HR: 1.505, P=.047), TiTR <70% (HR: 1.931, P=.004), number of international normalized ratio checks (HR: 0.988, P<.001), digoxin (HR: 1.855, P=.008), and proton-pump inhibitors (HR: 0.452, P<.001) were independently associated with CVEs.

CONCLUSIONS

High TtTR is associated with poorer long-term quality of VKAs therapy. Patients with TtTR >18days or with high SAMe-TT₂R₂ score should be considered for treatment with non-vitamin K oral anticoagulants.

Clinical characteristics and prevalence of adrenal insufficiency in hemodynamically stable patients with cirrhosis

It is well known that adrenal insufficiency is common in septic shock or hemodynamically unstable patients. But, there is as yet no sufficient clinically significant data about the exact prevalence or differences in the cause of cirrhosis with adrenal insufficiency. To investigate adrenal insufficiency prevalence in hemodynamically stable patients with cirrhosis and determine differences based on cirrhosis severity or etiology.From July 2011 to December 2012, 69 hemodynamically stable patients with cirrhosis without infection admitted at Hallym University Medical Center were enrolled. Adrenal insufficiency was defined as a peak cortisol level < 18 μg/dL, 30 or 60 minutes after 250 μg Synacthen injection.The study included 55 male patients (79.7%), and the mean age was 57.9 ± 12.9 years. Cirrhosis etiology was alcohol consumption, HBV, HCV, both viral and alcohol related, and cryptogenic in 49, 15, 7, 11, 9 patients, respectively. Adrenal insufficiency occurred in 24 patients (34.8%). No differences were found in age, sex, mean arterial pressure, heart rate, HDL, cirrhosis etiology, degree of alcohol consumption, encephalopathy, variceal bleeding history, or hepatocellular carcinoma between patients with or without adrenal insufficiency. Serum albumin level was lower (P < .05), and INR was higher (P < .05) in patients with than in those without adrenal insufficiency. However, multivariate analysis revealed no independent adrenal insufficiency predictor. Significant negative correlations were found between Child-Pugh score and peak cortisol levels (γ=-0.365, P = .008).Adrenal insufficiency was frequent even in hemodynamically stable patients with cirrhosis and tended to be associated with only liver disease severity, being unrelated to cirrhosis etiology.

Prediction of long-term net clinical outcomes using the TIMI-AF score: Comparison with CHA2DS2-VASc and HAS-BLED

The TIMI-AF score was described to predict net clinical outcomes (NCOs) in atrial fibrillation (AF) patients receiving warfarin. However, this score derived from the ENGAGE AF-TIMI 48 trial, and no external validation exists in real world clinical practice. We tested the long-term predictive performance of the TIMI-AF score in comparison with CHA₂DS₂-VASc and HAS-BLED in a 'real-world' cohort of anticoagulated AF patients.

METHODS

We included 1156 consecutive AF patients stable on vitamin K antagonist (INR 2.0-3.0) during 6 months. The baseline risk of NCOs (composite of stroke, life-threatening bleeding, or all-cause mortality) was calculated using the novel TIMI-AF score. During follow-up, all NCOs were recorded and the predictive performance and clinical usefulness of TIMI-AF was compared with CHA₂DS₂-VASc and HAS-BLED.

RESULTS

During 6.5 years (IQR 4.3-7.9), there were 563 NCOs (7.49%/year). 'Low-risk' (6.07%/year) and 'medium-risk' (9.49%/year) patients defined by the TIMI-AF suffered more endpoints that low- and medium-risk patients of CHA₂DS₂-VASc and HAS-BLED (2.37%/year and 4.40%/year for low risk; 3.48%/year and 6.39%/year for medium risk, respectively). The predictive performance of TIMI-AF was not different from CHA₂DS₂-VASc (0.678 vs 0.677, P = .963) or HAS-BLED (0.644 vs 0.671, P = .054). Discrimination and reclassification did not show improvement of prediction using the TIMI-AF score, and decision curves analysis did not demonstrate higher net benefit.

CONCLUSIONS

In VKA-experienced AF patients, the TIMI-AF score has limited usefulness predicting NCOs over a long-term period of follow-up. This novel score was not superior to CHA₂DS₂-VASc and HAS-BLED identifying low-risk AF patients.

Efficacy of Warfarin Anticoagulation and Incident Dementia in a Community-Based Cohort of Atrial Fibrillation

OBJECTIVE

To study the association between time in therapeutic range (TTR) during warfarin therapy and risk of dementia in a population-based cohort of incident atrial fibrillation (AF).

PATIENTS AND METHODS

We conducted an observational population-based study of 2800 nondemented patients with incident AF from January 1, 2000, through December 31, 2010. The association of incident dementia with warfarin therapy and TTR was examined using Cox proportional hazards regression models.

RESULTS

Mean patient age was 71.2 years; 53% were men (n=1495), and warfarin was prescribed to 50.5% (n=1414) within 90 days of AF diagnosis. Incident dementia diagnosis occurred in 357 patients (12.8%) over a mean ± SD follow-up of 5.0±3.7 years. After adjusting for confounders, warfarin therapy was associated with a reduced incidence of dementia (hazard ratio [HR], 0.80; 95% CI, 0.64-0.99). However, only those in the 2 highest quartiles of TTR were associated with lower risk of dementia. A 10% increase in TTR with a 10% reduction in time spent in the subtherapeutic (HR, 0.71; 95% CI, 0.64-0.79) and supratherapeutic (HR, 0.67; 95% CI, 0.57-0.79) ranges were associated with decreased risk of dementia.

CONCLUSION

In the community, warfarin therapy for AF is associated with a 20% reduction in risk of dementia. Increasing TTR on warfarin is associated with reduced risk of dementia. The risk of dementia was reduced with a reduction in time spent in subtherapeutic and supratherapeutic international normalized ratio range. Effective anticoagulation may prevent cognitive impairment in patients with AF.

Thrombolysis in stroke patients: Comparability of point-of-care versus central laboratory international normalized ratio

BACKGROUND

In acute stroke patients, thrombolysis is one gold standard therapy option within the first four hours after the ischemic event. A contraindication for thrombolysis is an International Normalized Ratio (INR) value >1.7. Since time is brain, rapid and reliable INR results are fundamental. Aim was to compare INR values determined by central laboratory (CL) analyzer and Point-of-Care Testing(POCT)-device and to evaluate the quality of POCT performance in cases of potential therapeutic thrombolysis at a certified stroke unit.

METHODS

In 153 patients INR measurements using POCT-devices (HEMOCHRON Signature Elite®) were compared to INR measurements (BCS®XP) performed at the central laboratory. Outlier evaluation was performed regarding the critical thrombolysis cut-off.

RESULTS

Overall, we demonstrated a significant correlation (r = 0.809, p<0.0001) between both measurement methods. Mean value of the absolute difference between CL-INR and POCT-INR measurements was 0.23. In 95.4% of these cases, no differences regarding the critical cut-off (INR 1.7) were observed. POCT-INR values tended to be higher than the CL-INR values (p = 0.01). In 4.6% cases, a different value regarding thrombolysis cut-off was found. All patients were >75 years.

CONCLUSIONS

POCT-INR measurements based on our POCT concept are suitable to determine INR values in critical stroke patients. Nevertheless, outlier evaluation is mandatory.

Long-term stability and reproducibility of Coagu Chek test strips

Whole-blood point-of-care testing prothrombin time monitors are being used on an increasing scale for the monitoring of oral anticoagulant therapy. These monitors are used with disposable test strips containing tissue factor reagent. The purpose of the present study was to assess the stability of different Coagu-Chek-S strip lots for a period of one year. Ten strip lots introduced successively in the Netherlands were obtained from the manufacturer's representative and stored at 4–8°C. Six deep-frozen pooled plasmas were analyzed for the prothrombin time and INR with the strips at six or seven occasions spread over one year. The test plasmas were recalcified immediately before application to the Coagu Chek-S system. Regression analysis was performed on the clotting times obtained with each plasma. In the majority of cases (i.e. 95%), no significant change was observed at the 5% significance level. A significant change was observed in only 3 cases. In addition, a ranking statistic was used as test of a monotonic relationship in the two-way analysis of variance. The results of the ranking statistic were not significant for any strip lot, indicating that the test strips were stable under these storage conditions. The reproducibility of INR measured with the Coagu Chek-S was assessed. The mean within-run coefficient of variation (CV) of INR ranged from 2.58% to 3.36% (CV). The between-lot variation of the mean INR ranged from 3.2 to 4.5 % (CV). The over-all variation of single INR measurements, i.e. including between-lot and within-lot, ranged from 5.0 to 6.0 % (CV).

Multicentre ISI assignment and calibration of the INR measuring range of a new point-of-care system designed for home monitoring of oral anticoagulation therapy

The new CoaguChek XS system is designed for use in patient selftesting. It is the successor of the current CoaguChek S system. The detection principle is based on the amperometric measurement of the thrombin activity initiated by starting the coagulation cascade using a human recombinant thromboplastin. This study was performed to assign the International SEnsitivity Index (ISI) to the new test according to the WHO guidelines for thromboplastins and plasmas used to control anticoagulant therapy, and to establish the measuring range of the new system. At four study sites a total of 90 samples of normal donors and 291 samples of warfarin-, phenprocoumon- or acenocoumarol-treated patients were included in the study.The ISI value of the new test was assigned against the human recombinant reference thromboplastin rTF/95 at each site using the samples from stabilized patients in the International Normalized Ratio (INR) range between 1.5 and 4.5 only. The new point-of-care system’s measuring range between 0.8 and 8 INR was calibrated against the mean INR of rTF/95 and AD149 using polynomial regression. ISIs were (CV of the slope): Site 1: ISI 0.99 (1.1%); Site 2: ISI 1.02 (2.0%); Site 3: ISI 1.03 (1.1%); Site 4: ISI 1.00 (1.4%). All regression lines calculated from patient-only data pass through the normal donor data points.All CVs of the slopes of the orthogonal regression lines are well below 3%,thus fulfilling the requirements of the WHO guidelines. The mean ISI for the new CoaguChek XS PT Test is 1.01.

Predictors of warfarin dose requirements in South African patients attending an anticoagulation clinic

INTRODUCTION

Warfarin is the most common oral anticoagulant for the treatment and prevention of thromboembolic disease. However, it has a wide interpatient variability in dose requirements due to various genetic and clinical factors.

MATERIALS AND METHODS

This study investigated the effect of clinical and genetic factors on the variability of warfarin dose requirements in 147 South African patients (81 white and 66 black). The study was performed at a University Hospital Anticoagulation Clinic managed by nursing sisters at the Charlotte Maxeke Johannesburg Academic Hospital.

RESULTS

The most common indication for anticoagulation was atrial fibrillation (n = 55, 37.4%). The mean warfarin dose was significantly higher in black patients as compared to white patients (5.4 ± 2.9 mg/day and 3.8 ± 2.1 mg/day, respectively; P < 0.001). Older age was significantly associated with a lower maintenance warfarin dose (P < 0.001). Drugs which decreased the international normalized ratio (INR) were significantly associated with a higher maintenance warfarin dose of 6.4 ± 3.4 mg/day (P < 0.034). In contrast, there was no significant difference in warfarin dosage requirements in the presence of CYP2C9 and VKORC1 variant alleles (P > 0.05). Patients, however, homozygous for CYP2C9 *1,*3, and VKORC1 required less than 5 mg/day of warfarin to maintain the INR within the therapeutic range.

CONCLUSION

In conclusion, this study indicates that clinical characteristics including; age, ethnic group, and drugs which decrease the INR might help to predict better dose requirements in this population group and thereby reduce the risk of bleeding and thrombotic complications.

Anticoagulation Monitoring Part 1: Warfarin and Parenteral Direct Thrombin Inhibitors

OBJECTIVE:

To review the availability, mechanisms, limitations, and clinical application of point-of-care (POC) devices used in the management of warfarin and parenteral direct thrombin inhibitors.

DATA SOURCES:

Scientific articles were identified through a MEDLINE search (1966–August 2004), manufacturer Web sites, additional references listed in articles and Web sites, and abstracts from scientific meetings.

STUDY SELECTION AND DATA EXTRACTION:

English-language literature from clinical trials was reviewed to evaluate the accuracy, reliability, and clinical application of POC monitoring devices.

DATA SYNTHESIS:

The prothrombin time expressed as the international normalized ratio (PT—INR) is a well-established test for monitoring warfarin anticoagulation. Multiple devices are available for POC testing. Because there is no universally accepted standard, the performance of each device is typically tested against a standard test performed in a reference laboratory. Performance of currently available devices, as measured by correlations to a standard reference laboratory PT—INR, may be considered very good and acceptable for use in patient care. Utilization of patient self-testing and patient self-monitoring of warfarin anticoagulation using POC devices is increasing. Parenteral direct thrombin inhibitors are typically monitored using a standard laboratory activated partial thromboplastin time. Some research has shown that POC monitoring of direct thrombin inhibitors using the ecarin clotting time is helpful for patients undergoing cardiopulmonary bypass surgery, although that test is not readily available.

CONCLUSIONS:

POC testing for anticoagulation therapy has been available for >20 years. Multiple POC devices are available to monitor warfarin. There is some variability in results between devices and between reagents used in the same device. Despite these limitations, POC monitoring of warfarin via the PT—INR is an integral part of clinical practice. Additional research evaluating POC monitoring of direct thrombin inhibitors is necessary.

Optimizing the Verification of Mean Normal Prothrombin Time (MNPT) and International Sensitivity Index (ISI) for Accurate Conversion of Prothrombin Time (PT) to International Normalized Ratio (INR)

The Prothrombin Time (PT) assay is the most common test performed in hemostasis laboratories, most commonly as converted to an international normalized ratio (INR) to monitor anticoagulant therapy using vitamin K antagonists (VKAs) such as warfarin. Although the INR is meant to standardize PT values by taking into consideration reagent and instrument variability, substantial inter-laboratory variation in INRs still exists and suggests that this can be further improved. This paper describes the PT test, its conversion to an INR value, and methods to improve the accuracy of INRs by improving the determination of critical components to the INR, namely the mean normal prothrombin time (MNPT) and the international sensitive index (ISI).

Probable Warfarin–Simvastatin Interaction

Objective:

To report and discuss a case of fatal cerebral hemorrhage following a switch from atorvastatin to simvastatin in a patient taking warfarin.

Case Summary:

An 82-year-old white female was admitted to the hospital because of an international normalized ratio (INR) value greater than 8, which was detected at a routine follow-up visit to monitor warfarin therapy. Four weeks earlier her lipid-lowering therapy had been switched from atorvastatin 10 mg daily to simvastatin 10 mg daily. She had been treated with 2.5 mg of warfarin daily for almost 30 years due to episodes of deep venous thrombosis and lung embolism. Her INR had been stable within the treatment range (2.0–3.5) for more than 2 years before the INR increase. Upon hospitalization, she was given 5 mg of vitamin K orally, A few hours later she lost the feeling and movement of her right arm and a computed tomography scan showed major bleeding in the left cerebral hemisphere. She died the following day.

Discussion:

One study has shown a lack of interaction between warfarin and atorvastatin. In comparison, 3 studies have shown significant increases (10–30%) in warfarin effect and/or reductions in dose requirement after starling concomitant simvastatin treatment. The interaction mechanism between simvastatin and warfarin is not known but is possibly associated with reduced elimination of warfarin. Use of the Naranjo probability scale showed that the likelihood of warfarin-induced INR increase following the switch to simvastatin was probable.

Conclusions:

Atorvastatin and simvastatin appear to differ in their potential to interact with warfarin. Clinicians should be aware of the interaction risk when starting simvastatin treatment in patients on warfarin therapy.

Comparison of the Abilities of Summary Measures of International Normalized Ratio Control to Predict Clinically Relevant Bleeding

BACKGROUND

Limited research has compared the measures of summarizing international normalized ratio (INR) control over time. Measures that are more predictive of patient outcomes would be preferred as would those that are easier to calculate and understand.

METHODS AND RESULTS

We examined 676 patients who received long-term warfarin therapy to treat atrial fibrillation: 125 patients who experienced major hemorrhage and 551 matched controls who did not. Patient INR control was characterized using various measures, from simple (proportion of INR values in range) to complex (eg, area under the curve above target range, squared) measures. Conditional logistic regression was used to examine the ability of each measure to predict the outcome of clinically relevant bleeding across quintiles of control. All measures were associated with clinically relevant bleeding to some extent: patients with the poorest control had significantly more bleeding events compared with patients with the best control. The measure most strongly associated with bleeding was a combination of percent time in therapeutic range and INR variability (odds ratio of 4.34, comparing the lowest to the highest quintiles of control). The strongest single predictor was INR variability, followed closely by time in therapeutic range. More computationally complex measures, which had been expected to perform better, were not so strongly associated with bleeding.

CONCLUSIONS

INR variability was the most strongly associated predictor of clinically relevant bleeding followed closely by time in therapeutic range. Using both measures together had an even stronger association. These findings support continued use of INR variability, time in therapeutic range, or both for research and quality assurance efforts.

Point-of-care (POC) versus central laboratory instrumentation for monitoring oral anticoagulation

Point-of-care (POC) instruments employing fingerstick whole blood to monitor patients treated with warfarin are a popular alternative to complex, central laboratory coagulation analyzers utilizing citrated plasma derived from venipuncture. We investigated the accuracy of two widely utilized POC instruments for oral anticoagulation monitoring compared with a central laboratory instrument. Instrument-to-instrument variation differed for the two POC instruments, which correlated with the central laboratory instrument, but exhibited positive bias of 0.24-0.35 INR units. Positive bias increased as the INR values increased. We conclude that clinicians should exercise caution when interpreting results generated by POC monitors, particularly at high INR values. A high POC measurement of INR does not necessarily warrant decreasing the warfarin dose. Instead, a predefined cut-off range for high INR values generated by POC instruments should mandate confirmatory testing with central laboratory instrumentation.

Use of signals and systems engineering to improve the safety of warfarin initiation

Warfarin-dosing algorithms combine clinical factors and dosing history with the current international normalized ratio (INR) to estimate the therapeutic warfarin dose. Unfortunately, these approaches can result in an overdose if the INR is spuriously low. Our goal was to develop an alert mechanism based on prior INRs in addition to the current INR. Using data from the Genetics InFormatics Trial (GIFT) of Warfarin to Prevent DVT, we analyzed warfarin dose estimates for days 3 through 11 that were ≥10 % higher than an average of the previous two dose estimates. We fit a stepwise mixed model to current and prior dose estimates, and subsequently compared the root-mean-square-error (RMSE) in predicting the final therapeutic dose using the GIFT algorithm versus the mixed model. From 861 dosing records (obtain from 556 patients), 646 dosing records (75 %) were randomly selected for the derivation cohort and 215 dosing records (25 %) for the validation cohort. Using one prior dose estimate improved the accuracy of the warfarin dose estimate. Compared to a dose estimate based on current INR (GIFT algorithm), the mixed model reduced the RMSE in the derivation cohort by 0.0015 mg/day (RMSE 0.2079 vs. 0.2094; p = 0.039). In the validation cohort, the RMSE reduction was not significant. A mixed model of dose estimates based on the current and most recent INRs shows potential to improve the safety of warfarin dosing. Clinicians should be cautious about aggressively escalating the warfarin dose after an INR that is lower than expected.

PIVKA-II correlates with INR but not protein C or protein S concentrations in cord blood among newborns

BACKGROUND

Protein induced by vitamin K absence (PIVKA)-II, inactive precursor of prothrombin, is elevated in vitamin K (VK) deficiency. Our aims were to find the prevalence of VK deficiency in neonates, assess the utility of international normalized ratio (INR) as a screening tool, and explore the relationship between PIVKA-II, activated partial thromboplastin time (aPTT) and VK dependent anticoagulants.

METHODS

INR, aPTT, PIVKA-II, and proteins C and S activities were measured in neonatal cord blood prior to VK administration.

RESULTS

We found 45% of neonates had subclinical VK deficiency based on PIVKA-II levels and 7% based on INR. Receiver operating characteristic (ROC) analysis assessed the utility of INR in detecting >4 ng/mL of PIVKA-II and ROC of the area under the curve was 0.70 (95% CI 0.46-0.92, p = 0.07). Proteins C and S activities were normal for age and did not correlate with PIVKA-II [(r = 0.40, p = 0.14) and (r = 0.29, p = 0.29), respectively]. There was no association between aPTT and PIVKA-II (p = 0.83).

CONCLUSION

PIVKA-II seems to be a sensitive indicator of mild VK deficiency. Further studies are needed to investigate the lack of relationship between PIVKA-II and functional protein C or S levels.

[Ultrasound dynamics lysis apex thrombus as an objective criterion of effectiveness of anticoagulation therapy in venous thrombosis]

OBJECTIVE OF THE STUDY

To assess the effectiveness of anticoagulant therapy (ACT) for the treatment of patients with deep venous thrombosis (DVT) of the lower extremities.

MATERIAL AND METHODS

The study considered ultrasonic characteristics of lysis of the proximal part of thrombus: localization and nature of venous thrombosis, the length and diameter of the proximal floating part of the thrombus, and duration of the venous thrombosis. Depending on the ACT options patients were divided into 3 groups: Group 1 (18 patients) received rivaroxaban, group 2 (19 patients) received enoxaparin sodium with subsequent transition to warfarin, and 3 group (19 patietns) received enoxaparin sodium, followed by administration of rivaroxaban.

RESULTS

Treatment with rivaroxaban was preferable over standard ACT with enoxaparin/warfarin with regards to the lysis of thrombus when duration of thrombosis did not exceed 10 days. In 10.5% of patients who received warfarin flotation of thrombi remained for 14 days; the length of the floating part of the thrombi did not exceed 3 cm. Such circumstances and inability to reach a therapeutic INR value required cava filter placement. Treatment with enoxaparin sodium followed by the administration of rivaroxaban was found to be the most efficient ACT regimen as there was no negative dynamics of ultrasound characteristics of lysis of thrombi at any duration of the disease.

A Randomized Trial of Pharmacogenetic Warfarin Dosing in Naïve Patients with Non-Valvular Atrial Fibrillation

Genotype-guided warfarin dosing have been proposed to improve patient’s management. This study is aimed to determine whether a CYP2C9- VKORC1- CYP4F2-based pharmacogenetic algorithm is superior to a standard, clinically adopted, pharmacodynamic method. Two-hundred naïve patients with non-valvular atrial fibrillation were randomized to trial arms and 180 completed the study. No significant differences were found in the number of out-of-range INRs (INR<2.0 or >3.0) (p = 0.79) and in the mean percentage of time spent in the therapeutic range (TTR) after 19 days in the pharmacogenetic (51.9%) and in the control arm (53.2%, p = 0.71). The percentage of time spent at INR>4.0 was significantly lower in the pharmacogenetic (0.7%) than in the control arm (1.8%) (p = 0.02). Genotype-guided warfarin dosing is not superior in overall anticoagulation control when compared to accurate clinical standard of care.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01178034.

Improving transitions of care for patients on warfarin: The safe transitions anticoagulation report

Adverse drug events are common during the transition period after hospitalization, and anticoagulants are among the medication classes for which the incidence is highest. We aimed to develop a concise report to improve the timeliness of international normalized ratio (INR) testing and quality of warfarin management posthospitalization. We developed the Safe Transitions Anticoagulation Report (STAR), which contains essential information on anticoagulation and is embedded in the discharge summary, and implemented the report and associated workflow in a tertiary care hospital within an integrated healthcare system. We performed a retrospective administrative database review of 505 patients in the preintervention period and 292 patients in the intervention period who were discharged on warfarin and were established patients at an affiliated ambulatory practice. There was no change in the frequency of obtaining an INR value within 10 days of discharge (41.4% and 47.6%, respectively, P = 0.09), and no increase in attaining a therapeutic INR level within 10 days of discharge (17.0% and 21.2%, respectively, P = 0.14). Ambulatory clinicians reported that the STAR improved "workflow and efficiency" (58%) and "patient safety" (77%), and led to an altered warfarin dose for 34% of survey respondents. Our study found that a concise anticoagulation report embedded in the discharge summary was perceived by ambulatory physicians as improving patient safety, but had no impact on clinical outcomes, suggesting that this electronic medical record tool would need to be a component of a broader multifaceted intervention to be effective.

Spontaneous Resolution of Chronic Subdural Haematoma in a Patient Receiving Anticoagulant Therapy

Significant chronic subdural hematoma (CSDH) is usually a surgical emergency. Spontaneous resolution of CSDH has rarely been reported in the literature. We are reporting a case of spontaneous resolution of CSDH in a patient receiving anticoagulant therapy who had undergone mitral valve replacement surgery.

Comparison of two approaches of INR-follow-up and determinants of INR-stability

INTRODUCTION

Patients with atrial fibrillation (AF) and treated with coumarins need a close follow-up of the international normalized ratio (INR)-values. This can be done by the general practitioner (GP) or by a haematologist in an outpatient hospital clinic.

OBJECTIVE

To compare both ways of follow-up and to investigate determinants of stable INR-patterns.

METHODS

Cross-sectional single-centre study in patients with AF treated at the UZ Brussel, a university hospital in Brussels. Of the 113 patients included in the study, 71 had their INR followed-up by their GP and 42 similar patients were followed-up by a haematologist. Data of these 113 patients were further analysed to identify possible determinants for stable INR-values.

RESULTS

The time in therapeutic range (TTR) did not significantly differ between both groups. However, patients in the GP-group had significantly more INR-values under 2.0 compared to patients from the haematologist-group (P =  0.044), whereas patients in the haematologist-group had significantly more INR-values above 3.0 compared to patients from the GP-group (P = 0.038). Reimbursement costs of both ways of follow-up were comparable, but the out-of-pocket costs for the patient were lower in the GP-group. The time since AF diagnosis was the only significant determinant predicting a higher TTR.

CONCLUSION

Both approaches of follow-up seem to lead to the same TTR, yielding no reason to advocate one approach above the other. However, the patient costs were lower when followed-up by the GP.

Role of prophylactic vitamin K in preventing antibiotic induced hypoprothrombinemia

OBJECTIVE

To determine prophylactic role of single dose of vitamin K in prevention of antibiotic induced hypoprothrombinemia.

METHODS

This prospective comparative study included critically ill children in age group 2 mo to 12 y, admitted to a tertiary care hospital in India, likely to receive prolonged antibiotic therapy. One hundred twenty children, 60 in each group (A & B) were enrolled in the study. Patient allocation was done on alternate basis. Group A children received prophylactic vitamin K while group B did not. Baseline coagulation studies and other investigations were done in all children. Coagulation studies were repeated on day 10 and day 14 of antibiotic therapy and in between if required clinically. Children who developed deranged INR were given therapeutic vitamin K. If deranged INR returns to normal at 12 h of vitamin K administration then it indirectly confirms vitamin K deficiency. Analysis was done by fisher's t test and chi square test.

RESULTS

In children on prolonged antibiotic therapy, vitamin K deficiency was a common problem (15%). It was common in male sex, severe grade of protein energy malnutrition (PEM), N-methylthiotetrazole (NMTT) group containing antibiotics use and duration of antibiotic more than 10 d. It was same in children whether they received or did not receive prophylactic vitamin K on day 1 of antibiotic therapy (95% CI; p value 0.79).

CONCLUSIONS

Vitamin K deficiency is common problem in patients on prolonged antibiotic therapy. There is no role of single dose of prophylactic vitamin K in preventing antibiotic induced hypoprothrombinemia.

[COMPARATIVE EFFECTIVENESS AND SAFETY OF NEW ORAL ANTICOAGULANTS AND WARFARIN IN PATIENTS WITH AGE-SPECIFIC NON-VALVULAR ATRIAL FIBRILLATION]

This study was designed to compare effectiveness and safety of warfarin, direct thrombin inhibitor dabigatran, Xa factor inhibitors rivaroxaban and apixaban used to prevent stroke in 280 elderly patients in patients with age-specific non-valvular atrial fibrillation. The treatment of patients aged 65-74 and 75-80 yearsfor 2 years with dab itragan (110 mg b.i.d), apixaban (5 mg b. i. d), and rivaroxaban (20 mg once daily) prevented stroke as effectively as warfarin therapy but less frequently caused severe intracranial hemorrhage. It is concluded that these new anticoagulants can be used as alternative medication for antithrombotic therapy of elderly patients with age-specific non-valvular atrialfibrillation.

[Comparison of Empiric and Pharmacogenetic Approaches in Assessment of Efficacy of Anticoagulant Therapy]

We compared pharmacogenetic (PG) and standard approaches to selection of individual dose of warfarin on 2 groups of patients each comprising 17 persons. In the group with PG selection we took into consideration the result of preliminary genotyping of polymorphisms of VKORC1 and CYP2C9 genes known to be associated with individual warfarin dose. Control of warfarin therapy was carried out during 6 months, number of measurements of international normalized ratio (INR) exceeded 500. Dosing based on knowledge of genotype allowed to achieve therapeutic effect 5 days earlier than with traditional selection of individual dose (p=0.023). Number of INR values above 3.5 indicative of increased risk of bleeding was lower at PG compared with standard approach (3.1 and 7.7%, respectively, p=0.03). Carriers of *2 and/or *3 of CYP2C9 associated with lowering of activity of this cytochrome had greater lability of INR values during course of therapy with warfarin.

Influence of sampling on the determination of warfarin and warfarin alcohols in oral fluid

BACKGROUND AND OBJECTIVE

The determination of warfarin, RS/SR- and RR/SS-warfarin alcohols in oral fluid may offer additional information to the INR assay. This study aimed to establish an optimized sampling technique providing the best correlation between the oral fluid and the unbound plasma concentrations of these compounds.

MATERIALS AND METHODS

Samples of non-stimulated and stimulated oral fluid, and blood were collected from 14 patients undergoing warfarin therapy. After acidification, analytes were extracted with a dichloromethane/hexane mixture and determined by HPLC with fluorescence detection. Plasma samples were also ultrafiltered for the determination of the unbound fraction. The chromatographic separation was carried out in isocratic conditions with a phosphate buffer/methanol mobile phase on a C-18 reversed-phase column. The absence of interfering compounds was verified by HPLC-ESI-Q-TOF.

RESULTS

Stimulation generally increased the oral fluid pH to values close to blood pH in about 6 minutes. The concentration of warfarin and RS/SR-warfarin alcohols in oral fluid followed the same trend, whereas the concentration of RR/SS-warfarin alcohols was not affected. Six minute stimulation with chewing gum followed by collection with a polyester swab was the best sampling procedure, with a good repeatability (RSD < 10%) and relatively low inter-subject variability (RSD  = 30%) of the oral fluid to plasma ratio. This procedure provided strong correlations between the measured oral fluid and unbound plasma concentration of warfarin (r  =  0.92, p < 0.001) and RS/SR-warfarin alcohols (r  =  0.84, p < 0.001), as well as between stimulated oral fluid and total plasma concentration of warfarin (r  =  0.78, p < 0.001) and RS/SR-warfarin alcohols (r  =  0.81, p < 0.001).

CONCLUSION

The very good correlation between oral fluid and unbound plasma concentration of warfarin and RS/SR-warfarin alcohols suggests that oral fluid analysis could provide clinically useful information for the monitoring of anticoagulant therapy, complementary to the INR assay.

The clinical impact of different coagulometers on patient outcomes

Introduction

Long-term anticoagulation therapy using vitamin K antagonists (VKA) is used in millions of patients worldwide to reduce the risk of thrombotic or thromboembolic events. Control and monitoring of VKA therapy is improved by the regular self-measurement of international normalized ratio (INR) using a home monitoring device. This retrospective analysis of a large cohort of patients in the Netherlands seeks to determine whether the choice of INR monitor could have a clinical impact on patient outcomes.

Methods

The National Thrombosis Service provides medical supervision, training and support to anticoagulant patients eligible for home-monitoring of INR in the Netherlands. Two INR monitors (CoaguChek XS and INRatio2) have been distributed at random to patients since June 2011, and patient self-testing data (INR measurements and other clinical parameters) have been recorded to measure and improve treatment outcomes. The data have been retrospectively analyzed to determine any effect of the choice of monitor. Univariate and multivariate statistical tests are used to assess any differences between groups in terms of efficacy and safety parameters.

Results

Data from 4,326 patients were collated, and 156,507 INR values were included in the analysis. Over half the patients (54.3%) were being treated for atrial fibrillation, and 77.6% were prescribed acenocoumarol. There were few differences between the patient populations using the two different monitors. Anticoagulant control overall was good, with high percentage of time (87.9%) in the appropriate INR range and low incidence of excessively high or low INR values (0.085/month). Minor clinical events related to safety were low (0.78 per patient-year) and showed few differences between monitors. Mortality rates were similar [hazard ratio (HR) 1.05, 95% confidence interval (CI) 0.65–1.70].

Conclusion

Self-testing data from a large cohort of patients in the Netherlands suggest that there is no clinically relevant effect of the choice of coagulation monitor (CoaguChek XS or INRatio2) on the time in therapeutic range (TTR), minor or fatal outcomes of long-term anticoagulation management.

Electronic supplementary material

The online version of this article (doi:10.1007/s12325-014-0124-x) contains supplementary material, which is available to authorized users.