Oral vitamin K versus placebo to correct excessive anticoagulation in patients receiving warfarin: a randomized trial

Antithrombotic Medication and Major Complications After Mechanical Aortic Valve Replacement

Patients with mechanical aortic valve replacement (AVR) require lifelong vitamin K antagonist (VKA) therapy for stroke and systemic embolism prevention. However, VKA treatment predisposes patients to various types of bleeding. In the present study, we sought to assess the success of antithrombotic therapy and the occurrence and timing of strokes and bleeding events after mechanical AVR. A total of 308 patients who underwent isolated mechanical AVR were included in the study, and follow-up data were completed for 306 patients (99.4%). The median follow-up time was 7.3 (interquartile range 4.2 to 10.9) years. The risk for major bleeding was 5-fold compared with major stroke (6.2% vs 1.3% and 20.9% vs 4.0%, respectively; events rates 3.1 vs 0.5 per 100 patient-years, respectively) at 30-day and long-term follow-up, indicating good efficacy but inadequate safety of stroke prevention. At the time of the early postoperative major bleeding, the international normalized ratio was under the therapeutic range in 73.7% of the patients. However, most patients were on triple antithrombotic treatment consisting of subcutaneous enoxaparin, VKA, and a tail effect of discontinued aspirin. During the long-term follow-up, the most common site of bleeding was gastrointestinal (41.7%), followed by genitourinary bleeding (23.3%) and intracranial hemorrhage (18.3%). Furthermore, mortality was relatively high, with a 10-year survival estimate of 78.3%. In conclusion, although ischemic stroke is a well-identified adverse event after mechanical AVR, it seems that major bleeding is a frequent clinically relevant complication during perioperative and long-term follow-up. This finding underscores the recognition and management of modifiable bleeding risk factors.

Incidence and risk factors of warfarin therapy complications in community hospitals, central and eastern regions, Thailand: a retrospective, multicenter, cohort study

OBJECTIVES

Warfarin, like many other anticoagulants, has been linked to an elevated risk of bleeding proportional to the amount of anticoagulation used. Not only was the incidence of bleeding raised by the dosage, but the subtherapeutic international normalized ratio (INR) was also associated with increased thrombotic events. This retrospective cohort and multi-center study evaluated the incidence and risk factors of warfarin therapy complications in community hospitals in Thailand's central and eastern regions from 2016 to 2021.

RESULTS

Among 335 patients (683.90 person-year of follow-up), The incidence rate of warfarin complications was 4.91 events per 100 person-year. The independent factor associated with warfarin therapy complications was propranolol prescription (Adjusted RR: 2.29, 95%CI: 1.12-4.71). The secondary analysis was divided according to the outcome of the major bleeding and thromboembolic event. Major bleeding events, hypertension (Adjusted RR: 0.40, 95%CI: 0.17-0.95), amiodarone prescription (Adjusted RR: 5.11, 95%CI: 1.08-24.15), and propranolol prescription (Adjusted RR: 2.86, 95%CI: 1.19-6.83) were the independent risk factors. While in the major thrombotic event, non-steroidal anti-inflammatory drugs (NSAIDs) prescription was an independent factor (Adjusted RR: 10.65, 95%CI: 1.26-90.35).

The Relationship Among Intestinal Bacteria, Vitamin K and Response of Vitamin K Antagonist: A Review of Evidence and Potential Mechanism

The vitamin K antagonist is a commonly prescribed effective oral anticoagulant with a narrow therapeutic range, and the dose requirements for different patients varied greatly. In recent years, studies on human intestinal microbiome have provided many valuable insights into disease development and drug reactions. A lot of studies indicated the potential relationship between microbiome and the vitamin K antagonist. Vitamin K is absorbed by the gut, and the intestinal bacteria are a major source of vitamin K in human body. A combined use of the vitamin K antagonist and antibiotics may result in an increase in INR, thus elevating the risk of bleeding, while vitamin K supplementation can improve stability of anticoagulation for oral vitamin K antagonist treatment. Recently, how intestinal bacteria affect the response of the vitamin K antagonist remains unclear. In this review, we reviewed the research, focusing on the physiology of vitamin K in the anticoagulation treatment, and investigated the potential pathways of intestinal bacteria affecting the reaction of the vitamin K antagonist.

Prothrombin complex concentrates in cardiac surgery: where are we?

PURPOSE OF REVIEW

Major bleeding in cardiac surgery is commonly encountered, and, until recently, most frequently managed with fresh frozen plasma (FFP). However, a Cochrane review found this practice to be associated with a significant increase in red blood cell (RBC) transfusions and costs. These findings have led to off-label uses of prothrombin complex concentrates (PCCs) in cardiac surgery. The purpose of this review is to compare and contrast the use of FFP and PCC, review the components, limitations and risks of different types of PCCs, and discuss the latest evidence for the use of PCC versus FFP in cardiac surgery.

RECENT FINDINGS

A recent review and meta-analysis suggests that PCC administration in cardiac surgery is more effective than FFP in reducing RBC transfusions and costs.

SUMMARY

The current data supports the use of 4F-PCC instead of FFP as the primary hemostatic agent in cases of major bleeding in cardiac surgery. The use of PCCs is associated with reduced rates of RBC transfusions while maintaining a favorable safety profile. Clear advantages of PCC over FFP include its smaller volume, higher concentration of coagulation factors and shorter acquisition and administration times.

Randomized, placebo-controlled trial of orally administered vitamin K1 for warfarin-associated coagulopathy in Chinese patients with mechanical heart valves

PURPOSE

Warfarin-associated coagulopathy commonly occurs in patients undergoing treatment with this anticoagulant. This trial aimed to determine the efficacy of using low-dose orally administered vitamin K₁ to lower international normalized ratio (INR) values into the target range in a cohort of Chinese patients with mechanical heart valves.

METHODS

This was a double-blind, placebo-controlled, randomized trial. Chinese patients with mechanical heart valves who were undergoing warfarin treatment and who had INR values from 4.0 to 10.0 without bleeding were the subjects of this study. These patients were randomized into two treatment groups and were orally administered either vitamin K₁ (2.5 mg) or placebo. Warfarin was discontinued in both groups until INR values were ≤ 2.5. INR values on the day following treatment were the primary study outcome, with INR values on the following days and adverse clinical events over a 3-month follow-up serving as secondary study outcomes.

RESULTS

In total, 80 patients were enrolled in the present study, and 40 patients each were assigned to the placebo and vitamin K1 treatment groups. Patients administered vitamin K₁ exhibited a quick reduction in INR values relative to patients administered placebo (29 of 40 [72.5%] vs. 0 of 44 [0%] patients exhibiting INR values from 1.5-2.5 on the day following treatment, respectively, p = 0.000). Lower bleeding incidence was observed among patients administered vitamin K₁ relative to those administered placebo during follow-up (4 [10%] vs. 12 [30%] patients, respectively, p = 0.045). There were no instances of thromboembolic complications or warfarin resistance in either group.

CONCLUSION

Low-dose oral vitamin K₁ can be effectively administered to Chinese patients with mechanical heart valves taking warfarin to rapidly reduce elevated INR values.

Top consumer uses of bestselling, single-ingredient vitamin and mineral supplements

OBJECTIVE

Vitamin and mineral supplements are widely used for self-care of a variety of medical conditions, but little is known about the specific conditions for which they are used. This study mined consumer product reviews to determine specific ways vitamin and mineral supplements are being used therapeutically.

DESIGN/SETTING

A cross-sectional analysis of user reviews for top-selling, single-ingredient vitamin and mineral products from a popular online retailer was performed to identify the most frequently appearing words associated with medical conditions. Results of individual analyses were compared to achieve consensus on the top, relevant keywords for each supplement. The full text of the reviews was searched for these keywords to distinguish whether they referred to therapeutic uses or adverse effects.

RESULTS

A total of 14 vitamin and 11 mineral supplements were analyzed. The number of user reviews for the analyzed products varied from 41 for manganese to over 5000 for biotin and vitamin D (median = 547 reviews per product). Cohen's kappa test for investigator-selected keywords related to medical conditions was generally greater than 0.6, indicating good interrater reliability. From these lists, the top consumer self-care uses were identified for 24 supplements. Commonly reported adverse effects were also noted for several products.

CONCLUSION

This study used data mining to identify the top ways consumers use an array of bestselling, single-ingredient vitamin and mineral supplements. These results can provide healthcare and nutrition professionals with information to anticipate the supplement-related education needs of patients and provide researchers with priority areas for clinical studies.

Vitamin K versus warfarin interruption alone in patients without bleeding and an international normalized ratio > 10

BACKGROUND

Reversal of an international normalized ratio (INR) > 10 with vitamin K is recommended in patients experiencing bleeding; however, information on outcomes with reversal using vitamin K in non-bleeding patients is lacking.

OBJECTIVE

To compare clinical and safety outcomes between non-bleeding patients receiving warfarin with an INR > 10 who did and did not receive a prescription for vitamin K.

PATIENTS/METHODS

This was a retrospective cohort study conducted in an integrated health-care delivery system. Adult patients receiving warfarin therapy who experienced an INR > 10 without bleeding between 01/01/2006 and 06/30/2018 were included. Patients were assessed for an outpatient dispensing or in-office administration of vitamin K on the day of or the day after an INR > 10 and then clinically relevant bleeding, thromboembolism, all-cause mortality, and time to INR < 4 within the next 30 days.

RESULTS

A total of 809 patients was included with 332 and 477 who were and were not dispensed vitamin K, respectively. Overall, mean patient age was 71.7 years, 60.1% were female and the mean INR was 10.4 at presentation. There were no differences between groups in 30-day rates of bleeding or thromboembolism (both P > .05). Patients dispensed vitamin K had a higher likelihood of mortality (15.1% versus 10.1%, P = .032, adjusted odds ratio = 1.63, 95% confidence interval 1.03 to 2.57). Overall, time to an INR < 4 was similar between groups.

CONCLUSION

Vitamin K administration was not associated with improved clinical outcomes in asymptomatic patients with an INR > 10.

Vitamin K for reversal of excessive vitamin K antagonist anticoagulation: a systematic review and meta-analysis

Patients receiving vitamin K antagonists (VKAs) with an international normalized ratio (INR) between 4.5 and 10 are at increased risk of bleeding. We systematically reviewed the literature to evaluate the effectiveness and safety of administering vitamin K in patients receiving VKA therapy with INR between 4.5 and 10 and without bleeding. Medline, Embase, and Cochrane databases were searched for relevant randomized controlled trials in April 2018. Search strategy included terms vitamin K administration and VKA-related terms. Reference lists of relevant studies were reviewed, and experts in the field were contacted for relevant papers. Two investigators independently screened and collected data. Risk ratios (RRs) were calculated, and certainty of the evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation. Six studies (1074 participants) were included in the review and meta-analyses. Pooled estimates indicate a nonsignificant increased risk of mortality (RR = 1.42; 95% confidence interval [CI], 0.62-2.47), bleeding (RR = 2.24; 95% CI, 0.81-7.27), and thromboembolism (RR = 1.29; 95% CI, 0.35-4.78) for vitamin K administration, with moderate certainty of the evidence resulting from serious imprecision as CIs included potential for benefit and harm. Patients receiving vitamin K had a nonsignificant increase in the likelihood of reaching goal INR (1.95; 95% CI, 0.88-4.33), with very low certainty of the evidence resulting from serious risk of bias, inconsistency, and imprecision. Our findings indicate that patients on VKA therapy who have an INR between 4.5 and 10.0 without bleeding are not likely to benefit from vitamin K administration in addition to temporary VKA cessation.

American Society of Hematology 2018 guidelines for management of venous thromboembolism: optimal management of anticoagulation therapy

BACKGROUND

Clinicians confront numerous practical issues in optimizing the use of anticoagulants to treat venous thromboembolism (VTE).

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians and other health care professionals in their decisions about the use of anticoagulants in the management of VTE. These guidelines assume the choice of anticoagulant has already been made.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 25 recommendations and 2 good practice statements to optimize management of patients receiving anticoagulants.

CONCLUSIONS

Strong recommendations included using patient self-management of international normalized ratio (INR) with home point-of-care INR monitoring for vitamin K antagonist therapy and against using periprocedural low-molecular-weight heparin (LMWH) bridging therapy. Conditional recommendations included basing treatment dosing of LMWH on actual body weight, not using anti-factor Xa monitoring to guide LMWH dosing, using specialized anticoagulation management services, and resuming anticoagulation after episodes of life-threatening bleeding.

Conservative Management of Overanticoagulation in Patients With Low-Moderate Risk for Bleeding Complications

Despite long-standing experience with warfarin, anticoagulation clinic services are often confronted with the challenging clinical situation of patients with overanticoagulation. This requires repeat international normalized ratio (INR) monitoring and in some cases administration of vitamin K to minimize the risk of bleeding. A study was performed to determine the safety and efficacy of outpatient management in order to provide guidance on the management of patients with prolonged INRs. Patients on stable warfarin therapy for more than 1 month attending a dedicated academic hospital anticoagulation clinic who had an INR ≥5 were identified over a 1-year period. Follow-up INR results and outcomes were recorded for 30 days. One hundred and ninety-five episodes of overanticoagulation in 148 patients were identified. Patients were classified as low risk (n = 85, 57.4%) and moderate risk of bleeding (n = 63, 42.6%). The mean index INR was 7.22 (1.88). Management with low-dose oral vitamin K (n = 32, 16.4%) did not significantly result in a more rapid correction of the INR when compared to conservative management (n = 163, 83.6%; P = .103). Follow-up INR testing was performed at a mean of 11.1 (8.9) days from the index measurement. A mean of 1.6 (0.9) follow-up INR tests were performed per episode. During the 30-day follow-up, there was 1 (0.5%) episode of major bleeding and 1 (0.5%) death. The management of asymptomatic outpatients with overanticoagulation is associated with a low risk of major bleeding within 30 days. Conservative management of overanticoagulation is as effective as utilizing low-dose oral vitamin K.

Benefits and harms of 4-factor prothrombin complex concentrate for reversal of vitamin K antagonist associated bleeding: a systematic review and meta-analysis

Prothrombin complex concentrate (PCC) is used for reversal of vitamin K antagonists (VKA) in patients with bleeding complications. This study aims to assess benefits and harms of 4-factor PCC compared to fresh frozen plasma (FFP) or no treatment in VKA associated bleeding. PubMed, EMBASE and CENTRAL were searched from 1945 to August 2015. Studies reporting 4-factor PCC use for VKA associated bleeding and providing data on INR normalization, mortality or thromboembolic (TE) complications were eligible. Two authors screened titles and full articles for inclusion, extracted data, and assessed risk of bias. Mortality data were pooled using Mantel–Haenszel random effects meta-analysis. Nineteen studies were included (N = 2878); 18 cohort studies and one RCT. Six studies had good methodological quality, 9 moderate and 4 poor. Baseline INR values ranged from 2.2 to >20. The INR within 1 h after PCC administration ranged from 1.4 to 1.9, and after FFP administration from 2.2 to 12. PCC reduced the time to reach INR correction in comparison with FFP or no treatment. The observed mortality rate ranged from 0 to 43% (mean 17%) in the PCC, 4.8–54% (mean 16%) in the FFP and 23–69% (mean 51%) in the no treatment group. Meta-analysis of mortality data resulted in an OR of 0.64 (95% confidence interval [CI] 0.27–1.5) for PCC versus FFP and an OR 0.41 (95% CI 0.13–1.3) for PCC versus no treatment. TE complications were observed in 0–18% (mean 2.5%) of PCC and in 6.4% of FFP recipients. Four-factor PCC is an effective and safe option in reversal of VKA bleeding events.

Clinical manifestations and outcomes of severe warfarin overanticoagulation: from the EWA study

INTRODUCTION

Severe warfarin overanticoagulation is a risk factor for bleeding, but there is little information on its manifestations, prognosis and factors affecting the outcome. We describe the manifestations and clinical outcomes of severe warfarin overanticoagulation in a large group of patients with atrial fibrillation (AF).

MATERIAL AND METHODS

All international normalized ratio (INR) samples (n = 961,431) in the Turku University Hospital region between 2003 and 2015 were screened. A total of 412 AF patients with INR ≥9 were compared to 405 patients with stable warfarin anticoagulation for AF. Electronic patient records were manually reviewed to collect comprehensive data.

RESULTS

Of the 412 patients with INR ≥9, bleeding was the primary manifestation in 105 (25.5%). Non-bleeding symptoms were recorded in 165 (40.0%) patients and 142 (34.5%) had no symptoms. A total of 17 (16.2%) patients with a bleed and 67 (21.8%) without bleeding died within 30 days after the event. Intracranial haemorrhage strongly predicted death within 30 days. Other significant predictors were non-bleeding symptoms, active malignancies, recent bleed, history of myocardial infarction, older age, renal dysfunction and a recent treatment episode.

CONCLUSIONS

Bleeds are not the major determinant of the poor prognosis in severe overanticoagulation, as coincidental INR ≥9 findings also associate with high mortality. KEY MESSAGES Only a quarter of AF patients with INR ≥9 suffered a bleeding event and the clinical manifestation of INR ≥9 had a significant impact on patient outcome. The 30-day mortality rate in patients with INR ≥9 was high ranging from 9.2 to 32.7%. Several significant predictors of 30-day mortality after INR ≥9 were identified.

Clinical outcome of patients with a vitamin K antagonist-associated bleeding treated with prothrombin complex concentrate

BACKGROUND

Vitamin K antagonists (VKA) are used for the treatment of thromboembolism. Patients with severe VKA-associated bleeding require immediate restoration of haemostasis. Clinical studies on the effect of prothrombin complex concentrate (PCC) are heterogeneous with respect to outcome of bleeding.

OBJECTIVE

To evaluate the clinical outcome of patients treated with PCC for VKA-associated bleeding.

METHODS

We performed a cohort study of consecutive patients who received PCC for VKA-related bleeding in five Dutch hospitals. Data were collected by chart review on the bleeding event, international normalized ratio (INR), haemostatic efficacy, thromboembolic (TE) complications, and mortality. The primary outcome was effective haemostasis, assessed by an adaptation of the Sarode criteria with a surrogate outcome for patients with ICH without repeat CT.

RESULTS

One hundred patients were included. Mean age was 74 years, 54% were male and 79% received VKA for atrial fibrillation. Most patients presented with ICH (41%) or GI bleeding (36%). Effective haemostasis was achieved in 67/98 (68%) patients using the adapted classification. Surrogate outcomes were applied for 32 patients and data for two patients was missing. Median pre-treatment INR was 3.9 (IQR 2.9-5.8). One hour after PCC infusion, the INR was available for 50 patients and of these, 35 (70%) had an INR ≤1.4. TE complications occurred in five patients and 22 died (60% bleeding-related) within 30 days.

CONCLUSION

PCC achieved effective haemostasis in 68% of evaluable patients with VKA-associated bleeding. TE complication rates were low, but mortality rates were high, due to the large number of patients with ICH.

Anticoagulants

Anticoagulants are effective in the prevention and treatment of a variety of arterial and venous thrombotic disorders but are associated with an increased risk of serious bleeding complications. Based on well documented studies of patients using vitamin K antagonists the incidence of major bleeding is 0.5%/year and the incidence of intracranial bleeding is 0.2%/year, however, in real life practice this incidence may be even higher. Risk factors for bleeding are the intensity of anticoagulation, the management strategy to keep the anticoagulant effect in the desired range, and patient characteristics. Recently, a new generation of anticoagulants have been developed and is currently evaluated in clinical trials. Initial results show a similar or superior efficacy over conventional anticoagulant agents with a good safety profile. In case of serious bleeding complications in a patient who uses vitamin K antagonists, this anticoagulant treatment can be quickly reversed by administration of vitamin K or coagulation factor concentrates. For the newer anticoagulants, quick reversal strategies are more cumbersome, although some interventions, including prothrombin complex concentrates, show promising results in initial experimental studies.

Bleeding risk assessment and management in atrial fibrillation patients

In this executive summary of a Consensus Document from the European Heart Rhythm Association, endorsed by the European Society of Cardiology Working Group on Thrombosis, we comprehensively review the published evidence and propose a consensus on bleeding risk assessments in atrial fibrillation (AF) patients. The main aim of the document was to summarise ‘best practice’ in dealing with bleeding risk in AF patients when approaching antithrombotic therapy, by addressing the epidemiology and size of the problem, and review established bleeding risk factors. We also summarise definitions of bleeding in the published literature. Patient values and preferences balancing the risk of bleeding against thromboembolism as well as the prognostic implications of bleeding are reviewed. We also provide an overview of published bleeding risk stratification and bleeding risk schema. Brief discussion of special situations (e.g. periablation, peri-devices such as implantable cardioverter defibrillators [ICD] or pacemakers, presentation with acute coronary syndromes and/or requiring percutanous coronary interventions/stents and bridging therapy) is made, as well as a discussion of the prevention of bleeds and managing bleeding complications. Finally, this document puts forwards consensus statements that may help to define evidence gaps and assist in everyday clinical practice.

Antithrombotic Reversal Agents

The actively bleeding anticoagulated patient presenting to the emergency department requires rapid evaluation and treatment, which is made increasingly complicated by the ever-evolving antithrombotic treatment options used in medicine. Even with excellent supportive care, the timeliness with which reversal decisions need to be made continues to demand of the emergency practitioner a familiarity with the properties and general characteristics of a variety of antithrombotic agents. Reversal options vary and may include vitamin K, FFP, PCC, rFVIIa, platelets, and desmopressin, among others.

Management of Supratherapeutic International Normalized Ratio without Bleeding after Warfarin Use: An Evaluation of Vitamin K Administration (SUPRA-WAR-K Study)

BACKGROUND

For patients with supratherapeutic international normalized ratio (INR) and no evidence of bleeding, the 2012 guidelines of the American College of Chest Physicians discourage administration of vitamin K. At the study hospital, it was observed that vitamin K was frequently prescribed for patients with INR of 4.5 or higher and no bleeding.

OBJECTIVES

To compare efficacy and safety outcomes between holding warfarin alone and holding warfarin with administration of vitamin K and to compare these outcomes among various doses and routes of vitamin K administration in non-critical care inpatients experiencing supratherapeutic INR without evidence of bleeding.

METHODS

This single-centre retrospective chart review involved noncritical care inpatients with supratherapeutic INR (4.5-8.9) without evidence of bleeding. The primary outcomes were the change in INR 1 day after implementation of supratherapeutic INR management and the time to reach INR less than 3.0. The secondary outcomes were length of stay, frequency of warfarin resistance, incidence and duration of bridging anticoagulation, incidence of thromboembolism and major bleeding, and death.

RESULTS

Regardless of vitamin K dose, the administration of vitamin K combined with holding warfarin, relative to holding warfarin alone, was associated with a greater INR decrease 1 day after the intervention (mean ± standard deviation -3.2 ± 1.9 versus -0.9 ± 1.0, p < 0.001) and a shorter time to reach INR below 3.0 (1.9 ± 1.0 days versus 2.6 ± 1.4 days, p = 0.003). No statistically significant differences in any other outcomes were observed.

CONCLUSIONS

In hospitalized non-critical care patients with INR between 4.5 and 8.9 without evidence of bleeding, the combination of holding warfarin and administering vitamin K was associated with greater and faster decreases in INR than holding warfarin alone. No significant differences were found in clinically important outcomes. The practice of administering vitamin K in this population warrants further study and re-evaluation.

Intracranial hemorrhage in patients with atrial fibrillation receiving anticoagulation therapy

We investigated the frequency and characteristics of intracranial hemorrhage (ICH), the factors associated with the risk of ICH, and outcomes post-ICH overall and by randomized treatment. We identified patients with ICH from the overall trial population enrolled in the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation trial who received ≥1 dose of the study drug (n = 18 140). ICH was adjudicated by a central committee. Cox regression models were used to identify factors associated with ICH. ICH occurred in 174 patients; most ICH events were spontaneous (71.7%) versus traumatic (28.3%). Apixaban resulted in significantly less ICH (0.33% per year), regardless of type and location, than warfarin (0.80% per year). Independent factors associated with increased risk of ICH were enrollment in Asia or Latin America, older age, prior stroke/transient ischemic attack, and aspirin use at baseline. Among warfarin-treated patients, the median (25th, 75th percentiles) time from most recent international normalized ratio (INR) to ICH was 13 days (6, 21 days). Median INR prior to ICH was 2.6 (2.1, 3.0); 78.5% of patients had a pre-ICH INR <3.0. After ICH, the modified Rankin scale score at discharge was ≥4 in 55.7% of patients, and the overall mortality rate at 30 days was 43.3% with no difference between apixaban- and warfarin-treated patients. ICH occurred at a rate of 0.80% per year with warfarin regardless of INR control and at a rate of 0.33% per year with apixaban and was associated with high short-term morbidity and mortality. This highlights the clinical relevance of reducing ICH by using apixaban rather than warfarin and avoiding concomitant aspirin, especially in patients of older age. This trial was registered at www.clinicaltrials.gov as #NCT00412984.

Reversing vitamin K antagonists: making the old new again

Vitamin K antagonists (VKAs) are commonly used for the prevention and treatment of thrombotic disorders. The response to VKAs is highly variable due to their specific interaction with the vitamin K cycle, and hence interference with hepatic synthesis of vitamin K-dependent coagulation factors. Monitoring the anticoagulant effect of VKAs by assessing the patient's international normalized ratio (INR) is essential because complications are closely related to the intensity of anticoagulation. Treatment with VKAs contains a substantial risk of bleeding with a high case fatality rate. Reversal of VKAs is required in case of bleeding or a supratherapeutic INR, but also prior to high-risk surgery or interventions. Choice of methods to reverse VKAs depends on whether or not the patient is bleeding or is in need of an urgent procedure, and has to be based on the pharmacokinetic and pharmacodynamic properties of the VKA. Reversal strategies include withholding the VKA, administration of vitamin K₁, and substitution of vitamin K-dependent procoagulant factors, and need to be combined with measures according to general bleeding management.

Guidance for the practical management of warfarin therapy in the treatment of venous thromboembolism

Venous thromboembolism (VTE) is a serious and often fatal medical condition with an increasing incidence. The treatment of VTE is undergoing tremendous changes with the introduction of the new direct oral anticoagulants and clinicians need to understand new treatment paradigms. This article, initiated by the Anticoagulation Forum, provides clinical guidance based on existing guidelines and consensus expert opinion where guidelines are lacking. Well-managed warfarin therapy remains an important anticoagulant option and it is hoped that anticoagulation providers will find the guidance contained in this article increases their ability to achieve optimal outcomes for their patients with VTE Pivotal practical questions pertaining to this topic were developed by consensus of the authors and were derived from evidence-based consensus statements whenever possible. The medical literature was reviewed and summarized using guidance statements that reflect the consensus opinion(s) of all authors and the endorsement of the Anticoagulation Forum’s Board of Directors. In an effort to provide practical and implementable information about VTE and its treatment, guidance statements pertaining to choosing good candidates for warfarin therapy, warfarin initiation, optimizing warfarin control, invasive procedure management, excessive anticoagulation, subtherapeutic anticoagulation, drug interactions, switching between anticoagulants, and care transitions are provided.

Risk Factors for Bleeding in Hospitalized Patients with Elevated INR: No Vitamin K Therapy Received Versus Vitamin K Received

BACKGROUND

Supratherapeutic international normalized ratio (INR) in patients on warfarin is a common side effect. Updated guidelines recommend against using vitamin K to correct INRs 4.5 to 10 in the absence of bleeding. The impact of compliance with updated guidelines during hospitalization has not been fully explored.

METHODS

A retrospective, observational study was performed utilizing electronic medical records. The goal was to evaluate management of supratherapeutic INR values for medicine inpatients and identify differences in clinical outcomes among inpatients treated and not treated with vitamin K. Records from adult inpatients with at least one INR value between 4.5 and 9 were reviewed. A total of 51 records were evaluated. Thirty-four patients did not receive vitamin K compared to 17 who did. Bleeding events, readmissions rates, length of stay, and familiarity with new guidelines were studied.

RESULTS

Mean age of patients was 73 years, and 71% were female. No statistically significant differences were observed in bleeding events between patients who received vitamin K and those who did not: 2/17 (12%) and 1/34 (3%), respectively (P = .30). No differences in 30-day readmission rates (24% vs 18%; P = .71) or in length of stay (7 vs 4 days; P = .11) were found. All pharmacists (13 of 13) were familiar with CHEST 2012 guidelines on the management of supratherapeutic INR compared to 10 of 21 (48%) hospitalists (P = .001).

CONCLUSIONS

With the national focus on reduction of health care costs, health systems are looking at innovative ways to reduce readmission rates and length of stay. This study, which evaluated the use of vitamin K administration, showed no statistical difference between bleeding events, readmission rates, and length of stay in patients who received vitamin K. Education on the updates of guidelines may be beneficial, as many providers were not familiar with the changes in recommendations.

Variation in warfarin prescribing and dosing in the UK: a national survey of anticoagulation clinics

WHAT IS KNOWN AND OBJECTIVE

Clinical practice in the initiation, prescribing, dosing and monitoring of warfarin in the UK varies, but this has not been adequately documented. The objective was to undertake a survey on current clinical practice in this area, and how it compares with national guidelines that have been developed by the British Committee for Standards in Haematology.

METHODS

A national online survey of anticoagulation clinics was performed using Survey Monkey(®) . The survey was designed to capture data for prescribing, dosing and monitoring of anticoagulation with warfarin.

RESULTS

Of 85 clinics who responded to the survey, most were run by secondary care (68%), facilitated by specialist nurses (58%) and followed standard guidelines for the management of warfarin (87%). The majority of clinics indicated their target international normalized ratio (INR) for patients with atrial fibrillation (AF) (69/73; 94·5%) was between 2·0 and 3·0, but the indicated target INR for mechanical heart valves was more variable. Initiation and loading dosing regimens were a major source of variability with uncertainty surrounding individual patient factors such as age, ethnicity and BMI.

WHAT IS NEW AND CONCLUSIONS

Current practice amongst UK anticoagulation clinics largely follows current national guidelines but better guidance on dosing, taking into account factors that determine interindividual variability in daily warfarin dose requirements would improve and standardize oral anticoagulation with warfarin.

Plasma and Plasma Protein Product Transfusion: A Canadian Blood Services Centre for Innovation Symposium

Plasma obtained via whole blood donation processing or via apheresis technology can either be transfused directly to patients or pooled and fractionated into plasma protein products that are concentrates of 1 or more purified plasma protein. The evidence base supporting clinical efficacy in most of the indications for which plasma is transfused is weak, whereas high-quality evidence supports the efficacy of plasma protein products in at least some of the clinical settings in which they are used. Transfusable plasma utilization remains composed in part of applications that fall outside of clinical practice guidelines. Plasma contains all of the soluble coagulation factors and is frequently transfused in efforts to restore or reinforce patient hemostasis. The biochemical complexities of coagulation have in recent years been rationalized in newer cell-based models that supplement the cascade hypothesis. Efforts to normalize widely used clinical hemostasis screening test values by plasma transfusion are thought to be misplaced, but superior rapid tests have been slow to emerge. The advent of non-vitamin K-dependent oral anticoagulants has brought new challenges to clinical laboratories in plasma testing and to clinicians needing to reverse non-vitamin K-dependent oral anticoagulants urgently. Current plasma-related controversies include prophylactic plasma transfusion before invasive procedures, plasma vs prothrombin complex concentrates for urgent warfarin reversal, and the utility of increased ratios of plasma to red blood cell units transfused in massive transfusion protocols. The first recombinant plasma protein products to reach the clinic were recombinant hemophilia treatment products, and these donor-free equivalents to factors VIII and IX are now being supplemented with novel products whose circulatory half-lives have been increased by chemical modification or genetic fusion. Achieving optimal plasma utilization is an ongoing challenge in the interconnected worlds of transfusable plasma, plasma protein products, and recombinant and engineered replacements.

Potential antidotes for reversal of old and new oral anticoagulants

The prescription of new oral anticoagulants is on the rise. As opposed to vitamin K antagonists and heparins the new agents have single targets in the coagulation cascade, more predictable pharmacokinetics and they lack validated and available antidotes. In general, the new agents have similar or lower bleeding risk than vitamin K antagonists, especially risk of intracranial bleeding. Risk factors for bleeding are typically the same for old and new anticoagulants. Old age, renal dysfunction and concomitant antiplatelet agents seem to be recurring risk factors. Adequate supportive care and temporary removal of all antithrombotic agents constitute the basis for management of serious bleeding complications. With the exception of vitamin K (for vitamin K antagonists) and protamine (for heparin) the same array of prohemostatic agents--unactivated or activated prothrombin complex concentrate, and activated factor VIIa--have been tried for almost all anticocoagulants in different models, and for some agents also in patients, with varying success. Hemodialysis can reduce the level of dabigatran efficiently and activated charcoal may be used for very recent oral ingestion of lipophilic agents. In view of the shorter half life of the new agents compared to warfarin the need for reversal agents may be less critical. Nevertheless, highly specific reversal agents for the thrombin- and factor Xa-inhibitors are under development and might be available within two years.

Warfarin overdose: a 25-year experience

Warfarin, a vitamin K antagonist, is widely used for the prophylaxis and treatment of thromboembolic disease. While guidelines exist for management of a supratherapeutic international normalized ratio following therapeutic warfarin use, these guidelines are not designed for management of the acute warfarin overdose. There is a paucity of literature describing the latter. The primary objective of this manuscript is to characterize the coagulopathy and describe the bleeding events that occur after a warfarin overdose. A secondary goal is to describe the amount of vitamin K administered to patients presenting with warfarin overdoses. A retrospective chart review of patients admitted with an acute warfarin overdose at two tertiary care medical centers in the USA was conducted. Clinical characteristics were abstracted, and bleeding categories (major, minor, trivial) were defined a priori. Twenty-three patients were admitted during the time period; males accounted for 15/23 (62.5 %) subjects. The median (interquartile range (IQR)) age was 43 (32-48.5) years. Seventeen subjects received vitamin K, with a median (IQR) dose of 15 (10-50) mg. The maximal total amount of vitamin K administered to a single patient during the index hospitalization was 110 mg. Three bleeding events occurred; one classified as major, and two as minor. All patients made a full recovery. In this case series of acute warfarin overdose, nearly all patients developed a coagulopathy, and nearly three-quarters of patients received vitamin K. Bleeding events occurred in a minority of patients.

Long-term quality of VKA treatment and clinical outcome after extreme overanticoagulation in 14,777 AF and VTE patients

Vitamin K antagonists (VKA) are widely used in atrial fibrillation and venous thromboembolism (VTE). Their efficacy and safety depend on individual time in the therapeutic range (iTTR). Due to the variable dose-response relationship within patients, also patients with initially stable VKA treatment may develop extreme overanticoagulation (EO). EO is associated with an immediate bleeding risk, but it is unknown whether VKA treatment will subsequently restabilise. We evaluated long-term quality of VKA treatment and clinical outcome after EO. EO was defined as international normalized ratio (INR) ≥ 8.0 and/or unscheduled vitamin K supplementation. We included a consecutive cohort of initially stable atrial fibrillation and venous thromboembolism patients. In EO patients, the 90 days pre- and post-period were compared. In addition, patients with EO were compared with patients without EO using a matched 1:2 cohort. Of 14,777 initially stable patients, 800 patients developed EO. The pre-period was characterised by frequent overanticoagulation, and half of EO patients had an inadequate iTTR (< 65 %). After EO, underanticoagulation became more prevalent. Although the mean time between INR-measurements decreased from 18.6 to 13.2 days, after EO inadequate iTTR became more frequent (62 %), p-value < 0.001. A 2.3 times (95 % confidence interval [CI] 2.0-2.5) higher risk for iTTR< 65 % after EO, was accompanied by increased risk of bleeding (hazard ratio [HR] 2.1;CI 1.4-3.2), VKA-related death 17.0 (HR 17.0;CI 2.1-138) and thrombosis (HR 5.7;CI 1.5-22.2), compared to the 1600 controls. In conclusion, patients continuing VKA after EO have long-lasting inferior quality of VKA treatment despite intensified INR-monitoring, and an increased risk of bleeding, thrombosis and VKA-related death.

Influence of kidney function on risk of supratherapeutic international normalized ratio-related hemorrhage in warfarin users: a prospective cohort study

BACKGROUND

Anticoagulation management is difficult in chronic kidney disease, with frequent supratherapeutic international normalized ratios (INRs ≥ 4) increasing hemorrhagic risk. We evaluated whether the interaction of INR and lower estimated glomerular filtration rate (eGFR) increases hemorrhage risk and whether patients with lower eGFRs experience slower anticoagulation reversal.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

Warfarin pharmacogenetics cohort (1,273 long-term warfarin users); warfarin reversal cohort (74 warfarin users admitted with INRs ≥ 4).

PREDICTOR

eGFR, INR as time-dependent covariate, and their interaction in the pharmacogenetics cohort; eGFR in the reversal cohort.

OUTCOMES & MEASUREMENTS

In the pharmacogenetics cohort, hemorrhagic (serious, life-threatening, and fatal bleeding) risk was assessed using proportional hazards regression. In the reversal cohort, anticoagulation reversal was assessed from changes in INR, warfarin and metabolite concentrations, clotting factors (II, VII, IX, and X), and PIVKA-II (protein induced by vitamin K absence or antagonist II) levels at presentation and after reversal, using linear regression and path analysis.

RESULTS

In the pharmacogenetics cohort, 454 (35.7%) had eGFRs < 60 mL/min/1.73 m(2). There were 137 hemorrhages in 119 patients over 1,802 person-years of follow-up (incidence rate, 7.6 [95% CI, 6.4-8.9]/100 person-years). Patients with lower eGFRs had a higher frequency of INR ≥ 4 (P<0.001). Risk of hemorrhage was affected significantly by eGFR-INR interaction. At INR<4, there was no difference in hemorrhage risk by eGFR (all P ≥ 0.4). At INR≥4, patients with eGFRs of 30 to 44 and < 30 mL/min/1.73 m(2) had 2.2-fold (95% CI, 0.8-6.1; P=0.1) and 5.8-fold (95% CI, 2.9-11.4; P<0.001) higher hemorrhage risks, respectively, versus those with eGFRs ≥ 60 mL/min/1.73 m(2). In the reversal cohort, 35 (47%) had eGFRs < 45 mL/min/1.73 m(2). Patients with eGFRs < 45 mL/min/1.73 m(2) experienced slower anticoagulation reversal as assessed by INR (P=0.04) and PIVKA-II level (P=0.008) than those with eGFRs ≥ 45 mL/min/1.73 m(2).

LIMITATIONS

Limited sample size in the reversal cohort, unavailability of antibiotic use and urine albumin data.

CONCLUSIONS

Patients with lower eGFRs have differentially higher hemorrhage risk at INR ≥ 4. Moreover, because the INR reversal rate is slower, hemorrhage risk is prolonged.

Is bleeding a necessary evil? The inherent risk of antithrombotic pharmacotherapy used for stroke prevention in atrial fibrillation

Current European atrial fibrillation (AF) guidelines have assigned a strong recommendation for the initiation of antithrombotic therapy to prevent thromboembolism in all but those AF patients at low risk (or with contraindications). Furthermore, the selection of antithrombotic therapy is based on the absolute risks of thromboembolism and bleeding, and the relative risk and benefit for a given patient. By their very mechanism of action, antithrombotic agents used for stroke prevention in AF will potentially increase the risk of bleeding events. Moreover, the introduction of novel oral anticoagulation agents have introduced new, hitherto ill-defined, deficiencies in the authors' knowledge with respect to anticoagulation monitoring, availability of direct antidotes, drug-drug interactions and the ability to appropriately control and reverse their actions if bleeding events occur. The authors present a comprehensive review on all aspects of bleeding related to currently licensed antithrombotic agents used for stroke prevention in patients with AF.

Management of major bleeding events in patients treated with rivaroxaban vs. warfarin: results from the ROCKET AF trial

AIMS

There are no data regarding management and outcomes of major bleeding events in patients treated with oral factor Xa inhibitors.

METHODS AND RESULTS

Using data from ROCKET AF, we analysed the management and outcomes of major bleeding overall and according to the randomized treatment. During a median follow-up of 1.9 years, 779 (5.5%) patients experienced major bleeding at a rate of 3.52 events/100 patient-years with a similar event rate in each arm (n = 395 rivaroxaban vs. n = 384 warfarin). The median number of transfused packed red blood cells (PRBC) per episode was similar in both arms [2 (25th, 75th: 2, 4) units]. Overall, few transfusions of whole blood (n = 14), platelets (n = 10), or cryoprecipitate (n = 2) were used. Transfusion of fresh frozen plasma (FFP) was significantly less in the rivaroxaban arm (n = 45 vs. n = 81 units) after adjustment for covariates [odds ratio (OR) 0.43 (95% CI 0.29-0.66); P < 0.0001]. Prothrombin complex concentrates (PCC) were administered less in the rivaroxaban arm (n = 4 vs. n = 9). Outcomes after major bleeding, including stroke or non-central nervous system embolism (4.7% rivaroxaban vs. 5.4% warfarin; HR 0.89; 95% CI 0.42-1.88) and all-cause death (20.4% rivaroxaban vs. 26.1% warfarin; HR 0.69, 95% CI 0.46-1.04) were similar in patients treated with rivaroxaban and warfarin (interaction P = 0.51 and 0.11).

CONCLUSION

Among high-risk patients with atrial fibrillation who experienced major bleeding in ROCKET AF, the use of FFP and PCC was less among those allocated rivaroxaban compared with warfarin. However, use of PRBCs and outcomes after bleeding were similar among patients randomized to rivaroxaban or to warfarin.

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.

An update of consensus guidelines for warfarin reversal

• Despite the associated bleeding risk, warfarin is the most commonly prescribed anticoagulant in Australia and New Zealand. Warfarin use will likely continue for anticoagulation indications for which novel agents have not been evaluated and among patients who are already stabilised on it or have severe renal impairment. • Strategies to manage over-warfarinisation and warfarin during invasive procedures can reduce the risk of haemorrhage. • For most warfarin indications, the target international normalised ratio (INR) is 2.0-3.0 (venous thromboembolism and single mechanical heart valve excluding mitral). For mechanical mitral valve or combined mitral and aortic valves, the target INR is 2.5-3.5. • Risk factors for bleeding with warfarin use include increasing age, history of bleeding and specific comorbidities. • For patients with elevated INR (4.5-10.0), no bleeding and no high risk of bleeding, withholding warfarin with careful subsequent monitoring seems safe. • Vitamin K1 can be given to reverse the anticoagulant effect of warfarin. When oral vitamin K1 is used for this purpose, the injectable formulation, which can be given orally or intravenously, is preferred. • For immediate reversal, prothrombin complex concentrates (PCC) are preferred over fresh frozen plasma (FFP). Prothrombinex-VF is the only PCC routinely used for warfarin reversal in Australia and New Zealand. It contains factors II, IX, X and low levels of factor VII. FFP is not routinely needed in combination with Prothrombinex-VF. FFP can be used when Prothrombinex-VF is unavailable. Vitamin K1 is essential for sustaining the reversal achieved by PCC or FFP. • Surgery can be conducted with minimal increased risk of bleeding if INR ≤ 1.5. For minor procedures where bleeding risk is low, warfarin may not need to be interrupted. If necessary, warfarin can be withheld for 5 days before surgery, or intravenous vitamin K₁ can be given the night before surgery. Prothrombinex-VF use for warfarin reversal should be restricted to emergency settings. Perioperative management of anticoagulant therapy requires an evaluation of the risk of thrombosis if warfarin is temporarily stopped, relative to the risk of bleeding if it is continued or modified.

Reversal of oral anticoagulation

Although the use of dabigatran and rivaroxaban are increasing, data on the reversal of their effects are limited. The lack of reliable monitoring methods and specific reversal agents renders treatment strategies empirical, and as a result, treatment consists mainly of supportive measures. Therefore, we performed a systematic search of the PubMed database to find studies and reviews pertaining to oral anticoagulation reversal strategies. This review discusses current anticoagulation reversal recommendations for the oral anticoagulants warfarin, dabigatran, and rivaroxaban for patients at a heightened risk of bleeding, actively bleeding, or those in need of preprocedural anticoagulation reversal. We highlight the literature that shaped these recommendations and provide directions for future research to address knowledge gaps. Although reliable recommendations are available for anticoagulation reversal in patients treated with warfarin, guidance on the reversal of dabigatran and rivaroxaban is varied and equivocal. Given the increasing use of the newer agents, focused research is needed to identify effective reversal strategies and develop and implement an accurate method (assay) to guide reversal of the newer agents. Determining patient-specific factors that influence the effectiveness of reversal treatments and comparing the effectiveness of various treatment strategies are pertinent areas for future anticoagulation reversal research.

Novel oral anticoagulants for stroke prevention in patients with atrial fibrillation: dawn of a new era

Atrial fibrillation (AF) is an important cause of ischemic stroke and is the underlying cause of > 20% of all strokes, with increasing age being a risk factor. Until recently, warfarin was the only available oral anticoagulant used to decrease this risk in patients with AF. However, there are several disadvantages of warfarin use, such as the requirement for monitoring the international normalized ratio, its wide range of drug-food interactions, and its narrow therapeutic index. Thus, there has been a strong impetus for the development of newer oral anticoagulants with predictable pharmacokinetics that obviate the need for monitoring the international normalized ratio. The US Food and Drug Administration has approved a direct thrombin inhibitor (dabigatran) and 2 factor Xa inhibitors (rivaroxaban and apixaban) for stroke prevention in patients with nonvalvular AF. There are several other new oral anticoagulant agents on the horizon, including the factor Xa inhibitor edoxaban. This review article discusses the pharmacological properties, clinical trial data, and practical issues associated with the use of these novel oral anticoagulants.

Transitions of care in anticoagulation management for patients with atrial fibrillation

Thromboprophylaxis with oral anticoagulants (OACs) is an important but underused element of atrial fibrillation (AF) treatment. Reduction of stroke risk with anticoagulants comes at the price of increased bleeding risk. Patients with AF receiving anticoagulants require heightened attention with transition from one care setting to another. Patients presenting for emergency care of anticoagulant-related bleeding should be triaged for the severity and source of the bleeding using appropriate measures, such as discontinuing the OAC, administering vitamin K, when appropriate, to reverse warfarin-induced bleeding, or administering clotting factors for emergent bleeding. Reversal of OACs in patients admitted to the hospital for surgery can be managed similarly to patients with bleeding, depending on the urgency of the surgical procedure. Patients with AF who are admitted for conditions unrelated to AF should be assessed for adequacy of stroke risk prophylaxis and bleeding risk. Newly diagnosed AF should be treated in nearly all patients with either warfarin or a newer anticoagulant. Patient education is critically important with all anticoagulants. Close adherence to the prescribed regimen, regular international normalized ratio testing for warfarin, and understanding the stroke risk conferred by both AF and aging are goals for all patients receiving OACs. Detailed handoff from the hospitalist to the patient's primary care physician is required for good continuity of care. Monitoring by an anticoagulation clinic is the best arrangement for most patients. The elderly, or particularly frail or debilitated patients who are transferring to long-term care, need a detailed transfer of information between settings, education for the patient and family, and medication reconciliation. Communication and coordination of care among outpatient, emergency, inpatient, and long-term care settings are vital for patients with AF who are receiving anticoagulants to balance stroke prevention and bleeding risk.

The effectiveness and safety of fixed low-dose prothrombin complex concentrates in patients requiring urgent reversal of warfarin

BACKGROUND

A rapid method of reversal is required for patients on warfarin who suffer acute bleeding or require emergency surgery. Prothrombin complex concentrates (PCCs) have recently been recommended by the Canadian Blood Services for use at a fixed low dose of 1000 IU of Factor (F)IX activity. The main goal of this study was to investigate both the effectiveness and the safety of fixed low-dose PCCs.

STUDY DESIGN AND METHODS

We retrospectively reviewed charts from 103 patients who received PCCs for reversal of warfarin therapy.

RESULTS

A total of 103 patients were treated with PCC at a single fixed dose of 1000 IU of F IX activity. Fifty patients (48.5%) had a final international normalized ratio (INR) response of not more than 1.5 and an additional 45 patients (43.7%) had a final INR response between 1.6 and 2.0. However, 86 patients (83.5%) had an excellent clinical response consisting of control of bleeding without the requirement of additional measures. In a multivariable model, patients who received fresh-frozen plasma and patients who were given doses greater than 1000 IU of PCC were both identified as predictors of a poor clinical response (odds ratio [OR] 3.48, 95% confidence interval [CI] 0.76-15.89, p = 0.11; and OR 10.8, 95% CI 2.08-56.28, 95% CI, p = 0.005, respectively). There were five adverse events up to 30 days after PCC use.

CONCLUSION

At a fixed dose of 1000 IU of F IX activity, PCC seems to be effective and safe but randomized controlled trials, specifically examining different doses of PCC, are required to confirm the above observations.

Bleeding risks and response to therapy in patients with INR higher than 9

An international normalized ratio (INR) higher than 9 is associated with a high risk of bleeding, yet most studies have focused on outpatients with lower INR. We retrospectively analyzed diagnosis, bleeding, treatment, and mortality in 162 patients with INR higher than 9, including inpatients and outpatients with and without warfarin treatment. Patients without anticoagulant treatment with INR higher than 9 had a poor prognosis, 67% experienced bleeding and 74% died. Among outpatients receiving warfarin with INR higher than 9, 11% had bleeding, but none died. Among inpatients receiving warfarin, 35% had bleeding and 17% died. Factors associated with bleeding were older age, renal failure, and alcohol use. Withholding warfarin or giving vitamin K treatment was ineffective at reducing the INR within 24 hours, whereas plasma infusion immediately dropped the INR to 2.4 ± 0.9. Because of underlying disease, comorbidities, and medications, hospitalized patients with INR higher than 9 may not respond quickly to withholding warfarin or vitamin K treatment, and plasma infusion may be needed to reduce INR and the risk of bleeding within 24 hours.