Analysis of Factors That Interrupt With INR Control in the First Anticoagulation Clinic Monitoring Jordanian Patients.

Multiple factors such as vitamin K consumption, drug interactions, herbs interactions, disease states, and alcohol intake affect international normalized ratio (INR) values and thus warfarin dosing. These variables have been described in general and for all patients in the literature. In contrast, the factors that affect INR control in a specific population are rarely studied. Being aware of these factors contributes a lot in maintaining an INR control and avoiding the supratherapeutic or subtherapeutic anticoagulation and the associated risks of hemorrhage or thromboembolism. The aim of this study is to recognize the specific population factors in Jordanian patients that interrupt INR control. Such recognition provides clinical pharmacists managing the anti-coagulation clinic (ACC) with necessary tools and predictors of dose adjustment, nontarget INR handling, and points to add on to the educational session. A total of 2788 patients were referred to the first clinical pharmacists managed ACC at Queen Alia Heart Institute-the only official referral hospital for cardiac patients in Jordan-for education and monitoring between November 1, 2013, and November 1, 2016. We evaluated specific population factors that interrupt INR control using a pretested, structured clinical data collection form. The patients were followed up regularly for achieving target INR (TINR). For patients who were not achieving TINR, the possible cause was examined thoroughly by reviewing the patient's medical file for recent medication intake, comorbidities, and laboratory results. Then the patients or their caregiver were asked direct questions regarding their diet, food supplements, cigarette smoking, shisha smoking, alcohol intake, herbs, and complementary medicine use and compliance, in addition to performing pharmacogenetic testing (polymorphisms of vitamin K-epoxide reductase complex [VKORC1] and cytochrome P450 2C9 [CYP2C9] genes) in special cases. For a total of 2788 patients, 89 488 INR values were included in the study. Of all, 20 365 (22.8%) were non-TINR values, 13 145 (14%) were subtherapeutic, and 7220 (8.1%) were supratherapeutic. All patients included in the study had a non-TINR at least 3 times (n = 65, 2.3%) and as frequent as 50 times (n = 21, 0.8%) during the study period. Non-TINR values ranged from 1 to 11. Serious side effects reported in 7 patients with uncontrolled INR, 6 were bleeding, which required hospitalization (2 upper gastrointestinal [GI] bleeding, 3 nasal bleeding, and 1 eye bleeding), 1 was cerebrovascular accident (CVA thrombolytic). Factors that interrupted INR control in our population, arranged in descending sequence, were concurrent medication use 46.9% (mainly Salicylates and Amiodarone), smoking cigarettes and shisha 17% (represented the most frequent single factor that caused non-TINR in the present study), a nonbalanced dietary vitamin K intake 16.88% caused changes in INR (lower) was related to an increase in the intake of vitamin K-rich food, were noticed to be much more in the spring season in Jordan (end of March and April mainly), herbal supplements 15.02%; Hawthorn (Crataegus, الزعرور) is an herb that lives widely in Jordan, and shockingly we found that it is used very commonly in our ACC patients and corresponded to an elevated INR <8 in 11 patients, and serious bleeding events that required hospitalization in 2 cases), noncompliance 1.49%, comorbid diseases 1%, malabsorption 0.53%, alcohol intake 0.39%, and VKORC1 A/G and CYP2C9 *1*1 genotype 0.15%. The analysis of factors that interrupted with INR control in our patients were both predicted and distinctive; most of these factors were reported previously by other researchers. On the other hand, many of the previously reported factors were not frequently detected in our patients, and the frequency of each of the realized factors was contributed differently to non-TINR in our population. Alarming factors causing non-TINR detected in our study include smoking both cigarettes and shisha, herbal use (Hawthorn and Ginseng), increased intake of vitamin K rich food in the spring season, and concurrent medication use (Salicylates, Amiodarone, Ciprofloxacin, nonsteroidal anti-inflammatory drugs [NSAIDS], Azithromycin, Clarithromycin: although the use of these drugs is mandatory sometimes, it can be replaced by an alternative, eg, antibiotics or monitored closely together with warfarin).

Do Patients With High CHA2DS2-VASc Scores Need High Intensity of Anticoagulants After Valve Surgery?

BACKGROUND: Asian patients on warfarin therapy usually have lower international normalized ratio (INR) intensities than those recommended by Western clinical practice guidelines. This study evaluated whether a high INR reduces the incidence of thromboembolism (TE) or bleeding events in Asian patients with high CHA2DS2-VASc scores after valve surgery.Methods and Results:Data of adult patients after valve surgery were retrieved from an integrated healthcare information system of a single hospital between 2014 and 2016. The INR was derived from the closest laboratory data before the index outpatient-clinic visit date. The endpoint of every record was determined as emergency room visit or hospitalization because of TE or bleeding event. A total of 37 TE or bleeding events were retrieved from 8,207 records; the annual incidence rate were 1.2% and 2.8% for low (0-2) and high (3-8) CHA2DS2-VASc score groups, respectively (P=0.007). The incidence rates were lowest for both groups at an INR of 1.5-2.0. High INR intensities did not reduce TE or bleeding incidence. INR >3.0 was associated with increased TE or bleeding incidence in the high-score group (6.8%/year vs. 2.0%/year, P=0.079). CONCLUSIONS: The optimal INR is 1.5-2.5 for low- or high-score Asian patients after valve surgery. INR >3.0 was associated with increased TE or bleeding incidence in the high-score group.

Inaccuracy of point-of-care international normalized ratio in rivaroxaban-treated patients.

OBJECTIVE: To report 2 cases in which point-of-care international normalized ratios (POC-INRs) measured using a Hemochron Jr. Signature Elite device (International Technidyne Corporation) were inaccurate in rivaroxaban-treated patients. CASE SUMMARIES: Therapy in an 86-year-old man with atrial fibrillation was converted from warfarin to rivaroxaban 15 mg twice daily because of a deep venous thrombotic event despite an INR of 2.4, which was within the therapeutic range. One week later a POC-INR was inadvertently measured, which was 6.3. In light of the POC-INR being markedly elevated, a laboratory test for INR was performed, which gave a result of 2.74. Therapy in a 66-year-old man was converted from war-farin to rivaroxaban 15 mg twice daily because of unstable INRs and a pulmonary embolism despite a therapeutic INR. Seven days after rivaroxaban was started, the patient's POC-INR was 9.2; simultaneously measured laboratory-determined INR was 2.0. For both patients, coagulation tests performed on follow-up visits revealed continued discordance between the POC and laboratory assays. DISCUSSION: Rivaroxaban is an oral factor Xa inhibitor with a predictable pharmacokinetic profile, allowing for a fixed-dose regimen without the need for coagulation monitoring. When patients' therapy is switched from rivaroxaban to warfarin, it is recommended that the drugs be given concurrently until the INR is 2.0 or higher, to ensure adequate anticoagulation during this well-recognized vulnerable period for stroke. POC testing is a common method of INR assessment in clinical practice. During ROCKET-AF (Rivaroxaban Once-Daily, Oral, Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation), POC-INRs were measured exclusively with the INRatio device (Hemosense), and values above 4 were seen very rarely (0.25%), which indicates that the values determined in our patients were highly unusual. CONCLUSIONS: Our 2 patients receiving rivaroxaban had POC-INRs elevated beyond what was expected; these measurements were discordant from INRs simultaneously measured via the laboratory. A prospective evaluation assessing the accuracy of other commonly used POC-INR devices in patients receiving rivaroxaban would determine whether our findings extend to other devices. Until that time, laboratory measurement of INR or POC-INR using an INRatio device is recommended when patients' therapy is transitioned from rivaroxaban to warfarin.

Evaluation of warfarin management with international normalized ratio self-testing and online remote monitoring and management plus low-dose vitamin k with genomic considerations: a pilot study.

STUDY OBJECTIVES: As better international normalized ratio (INR) control and self-testing reduce events in warfarin-treated patients, and vitamin K supplementation may improve INR control, our primary objective was to evaluate the effect of a system combining frequent INR self-testing with online remote monitoring and management (STORM2) and low-dose vitamin K supplementation on INR control; our secondary objectives were to assess the impact of STORM2 on clinician time and to evaluate the influence of pharmacogenomics on INR stability and warfarin dose after vitamin K supplementation. DESIGN: Prospective pre- and postintervention study. SETTING: Freestanding clinical research center. PATIENTS: Fifty-five patients treated with long-term warfarin therapy who were referred from four anticoagulation clinics and seven medical practices. INTERVENTION: All patients performed weekly INR self-testing and received vitamin K 100 µg/day and online anticoagulation management for 1 year. MEASUREMENTS AND MAIN RESULTS: INR control and time required for anticoagulation management were assessed, and an analysis of warfarin dosing and INR stability by genetic polymorphism subgroup (vitamin K epoxide reductase complex 1 [VKORC1] and cytochrome P450 2C9 isoenzyme) was performed; vitamin K product content was also analyzed. The percentage of time that the INR is within the time in therapeutic range (TTR) improved from 56% before the intervention to 81% after the intervention (p<0.0001), and time spent at extreme INR values of lower than 1.5 or higher than 5 was reduced from 3.1% to 0.4% (p=0.01). Clinician time was less than 10 minutes per four patient visits per month. Genetic polymorphisms did not correlate with INR stability or the increase in warfarin dose after vitamin K supplementation. The content of the vitamin K product, however, was only 34-76% of the labeled amount. Patients with the GG VKORC1 genotype required a higher warfarin dose than predicted by the genomic-based dosing chart in the warfarin package insert. CONCLUSION: The 25% point improvement in TTR with STORM2 is a greater improvement than reported previously with other efforts to improve TTR. STORM2 required a minimum amount of clinician time. Pharmacogenomics were not predictive of improved INR control or the magnitude of the warfarin dose after vitamin K supplementation, although the content of the product was unreliable. Patients with the GG VKORC1 genotype required a higher warfarin dose than predicted by the product information. The potential clinical impact of improved INR control with this method warrants comparisons with conventionally managed warfarin and with the new oral anticoagulants.

Anticoagulation control with daily low-dose vitamin k to reduce clinically adverse outcomes and international normalized ratio variability: a systematic review and meta-analysis.

STUDY OBJECTIVES: Difficulties managing warfarin therapy have led to speculation that daily supplementation with a low dose of vitamin K might improve anticoagulation control and clinical outcomes. Thus we sought to review the available medical literature systematically examining the effectiveness of low-dose vitamin K supplementation for the reduction of clinically relevant adverse events due to vitamin K antagonist (VKA) use and for stabilization of the international normalized ratio (INR). DESIGN: We searched the Medline and Embase databases, the Cochrane Library, International Pharmaceutical Abstracts, and the U.S. National Institutes of Health clinical trials registry for randomized controlled trials of vitamin K supplementation versus placebo in patients receiving a VKA. We evaluated the outcomes of hemorrhage, thromboembolic events, and percentage of time in therapeutic range (TTR) of INRs by using the Grading of Recommendations Assessment, Development and Evaluation system for rating quality of evidence in the abstracted studies. SETTING: All randomized controlled trials studies published between 1970 and August 2012 which fitted our search strategy. PATIENTS: Patients over the age of 18 years on VKA therapy. RESULTS: Of the 624 studies we identified and screened, three studies (626 patients) were included in the meta-analysis. Most of the patients had a satisfactory TTR at baseline. We found low-quality evidence--downgraded for imprecision and risk of bias (i.e., limitation in study design and/or execution)--of no effect of vitamin K use (100 to 200 µg) on hemorrhagic events (relative risk [RR] 3.2, 95% confidence interval [CI] 0.2-64.2) and thromboembolic events (RR 2.2, 95% CI 0.1-47.5) and a significant but clinically unimportant effect on TTR with an absolute increase of 3.5% (95% CI 1.1-6.0). CONCLUSION: This meta-analysis, despite the few studies and overall low quality, suggests no beneficial role of low-dose (100 to 200 µg) vitamin K supplementation on the reduction of clinically relevant adverse events in patients taking VKAs, despite a small improvement of the TTR. Data were insufficient, however, from patients with unstable INRs.

Treatment of warfarin-associated coagulopathy with vitamin K.

Warfarin is the most common form of oral anticoagulant therapy. Although it has indisputable benefit in the management of thromboembolic disease, warfarin-associated coagulopathy (WAC) is a well-documented complication of its use. As warfarin exerts its effect by impairing formation of the vitamin K-dependent clotting factors, a cornerstone of WAC management is vitamin K replacement. Daily vitamin K supplementation is an emerging approach to regulate international normalized ratios in difficult-to-control patients. Mild WAC without bleeding can often be managed with warfarin withdrawal alone. For excessive international normalized ratio elevation in the absence of bleeding, low-dose oral vitamin K (1?2.5 mg) is sufficient and achieves the same degree of international normalized ratio correction by 24 h as intravenous therapy. The stable patient with WAC and minor bleeding can also be given oral vitamin K, with correction of the underlying defect. Major bleeding should first be managed with factor replacement for immediate correction of the coagulopathy, using either a prothrombin complex concentrate or fresh-frozen plasma. High-dose vitamin K (10 mg) should be given concurrently via intravenous infusion to confer lasting correction. Warfarin resistance and vitamin K-associated anaphylaxis are rare. Despite development of new oral anticoagulant therapy compounds, warfarin will probably retain a prominent role in thromboembolism management for several years to come.

Prothrombin complex concentrates used alone in urgent reversal of warfarin anticoagulation.

BACKGROUND: Prothrombinex-VF (a three-factor prothrombin complex concentrate) contains little factor VII. Therefore, the Warfarin Reversal Consensus Guidelines from 2004 published by The Australasian Society of Haemostasis and Thrombosis recommend that it be administered with fresh frozen plasma to reverse warfarin anticoagulation. AIM: To evaluate the efficacy and safety of Prothrombinex-VF used alone in warfarin reversal. METHODS: Adult patients requiring urgent reversal of warfarin anticoagulation were defined as having achieved complete (target international normalized ratio (INR) <1.4) or partial reversal (target INR 1.4-2.0) of their anticoagulation. Prothrombinex-VF was given at doses of between 25 and 50 IU/kg based on the intent of reversal and an INR was obtained 30min post infusion. RESULTS: A total of 50 patients (mean age 72years, range 32-85years) was included. The median initial INR in the complete reversal arm (n= 35) was 3.5 (range 1.7-20) with 91% achieving the target INR (mean 1.1, range 0.9-1.4). In the partial reversal arm (n= 15) the mean initial INR was 5.6 (range 2.5-12) with 93% achieving the target INR (mean 1.6, range 1.4-2.2). There were no adverse effects attributed to Prothrombinex-VF. CONCLUSIONS: Prothrombinex-VF is very effective and safe when used alone to reverse warfarin anticoagulation. The supplementary use of fresh frozen plasma in these patients is not required. A review of the current Warfarin Reversal Consensus Guidelines is needed.

Intrahospital correlation of the international normalized ratio.

Background. Monitoring of oral anticoagulant therapy (OAT) is usually accomplished by measuring prothrombin time and the international normalized ratio (INR). However, thromboplastins have different responsiveness and sensitivity to vitamin K-dependent coagulation factors depletion. Several studies have shown INR variation when low sensitive thromboplastins are used. This study compared INR variability between two laboratories using highly sensitive thromboplastins. Methods. A total of 237 plasmas were tested, half of them from patients under OAT. Samples were tested simultaneously in two laboratories: in laboratory A, a Behring Coagulation Timer instrument and a human recombinant thromboplastin (Innovin, Dade Behring) (ISI 1.01) were used. In laboratory B, a Thrombolyzer Compact (Behnk Elektronik) and a rabbit brain thromboplastin (Simplastin Excel S, Organon Teknika) with an ISI of 1.30 were used. Statistical analysis was carried out according to the method of Bland and Altman. Results. Even though high correlation coefficients were obtained when comparing both laboratories, Bland-Altman analysis showed a variation of INR between laboratories ranging from -0.77 to +1.07. After logarithmic transformation of data, these values yielded a variation of the INR either 25% below or 44% above. Conclusions. These results are clearly inadequate for clinical use because such a variation would most probably induce the clinician to make a change in warfarin dose. Standardization of instruments, reagents, and controls is warranted to decrease this variation.

Standardization of the INR: how good is your laboratory's INR and can it be improved?

The prothrombin time (PT) assay is the most clinically ordered coagulation test and is most often used for monitoring of vitamin K antagonist (VKA) therapy (e.g., warfarin), where results are expressed as an international normalized ratio (INR). The INR is in essence the patient's PT "mathematically adjusted" to a standardized value by taking into account the peculiarities of the test system through applying two "correction factors" defined by an international sensitivity index (ISI) and mean normal prothrombin time (MNPT). Although some manufacturers provide assigned ISI values for specific PT reagents and instrumentation, it is still recommended practice that laboratories check or locally validate these ISIs, as well as estimate the MNPT based on the population being tested. Where a manufacturer does not provide an ISI, the laboratory needs to define its own (local ISI) value. Current recommendations suggest the use of commercial reference-plasma calibration sets, but there is limited information to validate their performance in laboratory practice. We report our personal experience with use of some of these materials, as well as review alternate or supplementary procedures for calibration and/or validation of ISI and for determination and validation of MNPT. In brief, our data and experience suggests that further verification checks should be performed prior to acceptance of ISI and MNPT estimates generated from commercial reference-plasma calibration sets. We detail various strategies to ensure that laboratory practices are optimized to provide INRs that accurately reflect a patient's true anticoagulant status and to thus assist their clinical therapeutic management.

Time to think outside the box? Prothrombin time, international normalised ratio, international sensitivity index, mean normal prothrombin time and measurement of uncertainty: a novel approach to standardisation.

BACKGROUND: The prothrombin time (PT) assay is the most clinically ordered coagulation test, and most often used for monitoring of vitamin K antagonist therapy (e.g., warfarin), where results are expressed as an international normalised ratio (INR). The INR is in essence the patient's PT 'mathematically adjusted' to a standardised value taking into account the peculiarities of the test system as defined by an ISI (international sensitivity index) and MNPT (mean normal prothrombin time). Although some manufacturers provide assigned ISI values for specific PT reagents and instrumentation, it is still recommended practice that laboratories check or validate these ISIs, as well as estimate the MNPT. Where an ISI is not provided by a manufacturer, the laboratory needs to estimate its own value. Current recommendations suggest the use of commercial reference-plasma calibration sets, but there is limited information on the performance of these in the field. RESULTS: We report a comparative study that assessed the utility of three such commercial calibration plasma sets, used as recommended, as well as alternate or supplementary procedures for estimation of ISI and MNPT. The latter included one novel approach using comparative data of 'existing' versus 'replacement' reagent, as well as assessment of external quality assurance data. Although MNPT value estimates were not grossly disparate, a wide variety of ISI values (e.g., 1.12-1.30 for our primary instrument) was obtained with the different plasma sets. CONCLUSION: Because of the above, further verification checks are required prior to acceptance of ISI and MNPT estimates generated from commercial plasma calibration sets. We also provide some recommendations regarding the process of standardisation of INR testing.

Anti-coagulant monitoring service delivery: a comparison of costs of hospital and community outreach clinics.

Anti-coagulated patients are monitored at regular intervals to ensure that their warfarin dosage is appropriate for their target International Normalized Ratio. The traditional setting for this monitoring has been the hospital clinic. Technological advances allow-- and with growing numbers of anti-coagulated patients, are leading to-- greater provision of monitoring clinics outside the hospital, at a more convenient location nearer patients' homes. This paper discusses the differences in organization between a hospital clinic and one set in the community (although provided by the hospital), and compares their costs. The comparison demonstrates the greater average cost per appointment in outreach of pound sterling 13.12 under current arrangements. Estimates are presented of incremental cost per appointment of pound sterling 3.93 and pound sterling 15.88 for a 10% increase in weekly patient numbers put through hospital and outreach clinics, respectively. Cost estimates are also presented for suggested alterations to hospital clinics that may reduce patient inconvenience, and the conditions under which outreach provision might be expanded at comparable cost to hospital provision are also examined.