Vitamin K dosing to reverse warfarin based on INR, route of administration, and home warfarin dose in the acute/critical care setting

Vitamin K: a potential missing link in critical illness-a scoping review

BACKGROUND

Vitamin K is essential for numerous physiological processes, including coagulation, bone metabolism, tissue calcification, and antioxidant activity. Deficiency, prevalent in critically ill ICU patients, impacts coagulation and increases the risk of bleeding and other complications. This review aims to elucidate the metabolism of vitamin K in the context of critical illness and identify a potential therapeutic approach.

METHODS

In December 2023, a scoping review was conducted using the PRISMA Extension for Scoping Reviews. Literature was searched in PubMed, Embase, and Cochrane databases without restrictions. Inclusion criteria were studies on adult ICU patients discussing vitamin K deficiency and/or supplementation.

RESULTS

A total of 1712 articles were screened, and 13 met the inclusion criteria. Vitamin K deficiency in ICU patients is linked to malnutrition, impaired absorption, antibiotic use, increased turnover, and genetic factors. Observational studies show higher PIVKA-II levels in ICU patients, indicating reduced vitamin K status. Risk factors include inadequate intake, disrupted absorption, and increased physiological demands. Supplementation studies suggest vitamin K can improve status but not normalize it completely. Vitamin K deficiency may correlate with prolonged ICU stays, mechanical ventilation, and increased mortality. Factors such as genetic polymorphisms and disrupted microbiomes also contribute to deficiency, underscoring the need for individualized nutritional strategies and further research on optimal supplementation dosages and administration routes.

CONCLUSIONS

Addressing vitamin K deficiency in ICU patients is crucial for mitigating risks associated with critical illness, yet optimal management strategies require further investigation.

IMPACT RESEARCH

To the best of our knowledge, this review is the first to address the prevalence and progression of vitamin K deficiency in critically ill patients. It guides clinicians in diagnosing and managing vitamin K deficiency in intensive care and suggests practical strategies for supplementing vitamin K in critically ill patients. This review provides a comprehensive overview of the existing literature, and serves as a valuable resource for clinicians, researchers, and policymakers in critical care medicine.

Approaches to Precision-based Anticoagulation management in the critically Ill

Anticoagulant therapy is commonly associated with a high incidence of avoidable adverse events, especially in the acute care setting. This has led to several initiatives by key national health care stakeholders, including specific attention to The Joint Commission's National Patient Safety Goals, to improve anticoagulation management. The subject of special populations has long been identified as challenging by clinicians with the use of anticoagulants. This is driven in part by numerous variables that can contribute to hard outcomes such as bleeding, thrombosis, length of stay, hospital re-admission, morbidity, and mortality. Despite the notable effort to improve the use of anticoagulants with numerous clinical trials, guidelines, guidance statements, and other sources of published evidence, notable difficulties continue to challenge practitioners in managing this class of medications. This is especially the case with very diverse critically ill populations where countless variables exist, many of which were never explored in trials or have historically been frequently excluded. Trials evaluating anticoagulation therapy often can only account for small portions of variables that may affect thrombosis and hemostasis, and study methods often do not reflect the constantly changing dynamic conditions seen in unique critically ill patients. Clinicians providing care to the numerous critically ill populations are faced with conditions that lead to relatively small therapeutic windows, which makes designing safe optimal anticoagulation management plans difficult when dealing with complex patients and mechanical support devices. The approach to crafting a successful management plan for anticoagulant therapy must incorporate the numerous variables that are continuously assessed and revised during the patient's time in the intensive care unit. We explore considerations and approaches when developing, assessing, and implementing an individualized or precision-based management plan that involves the use of anticoagulants in the critically ill. The skills and thought process provided will assist clinicians in managing this unique, variable, and challenging population.

Perioperative Management of Antithrombotic Therapy: An American College of Chest Physicians Clinical Practice Guideline

BACKGROUND

The American College of Chest Physicians Clinical Practice Guideline on the Perioperative Management of Antithrombotic Therapy addresses 43 Patients-Interventions-Comparators-Outcomes (PICO) questions related to the perioperative management of patients who are receiving long-term oral anticoagulant or antiplatelet therapy and require an elective surgery/procedure. This guideline is separated into four broad categories, encompassing the management of patients who are receiving: (1) a vitamin K antagonist (VKA), mainly warfarin; (2) if receiving a VKA, the use of perioperative heparin bridging, typically with a low-molecular-weight heparin; (3) a direct oral anticoagulant (DOAC); and (4) an antiplatelet drug.

METHODS

Strong or conditional practice recommendations are generated based on high, moderate, low, and very low certainty of evidence using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology for clinical practice guidelines.

RESULTS

A multidisciplinary panel generated 44 guideline recommendations for the perioperative management of VKAs, heparin bridging, DOACs, and antiplatelet drugs, of which two are strong recommendations: (1) against the use of heparin bridging in patients with atrial fibrillation; and (2) continuation of VKA therapy in patients having a pacemaker or internal cardiac defibrillator implantation. There are separate recommendations on the perioperative management of patients who are undergoing minor procedures, comprising dental, dermatologic, ophthalmologic, pacemaker/internal cardiac defibrillator implantation, and GI (endoscopic) procedures.

CONCLUSIONS

Substantial new evidence has emerged since the 2012 iteration of these guidelines, especially to inform best practices for the perioperative management of patients who are receiving a VKA and may require heparin bridging, for the perioperative management of patients who are receiving a DOAC, and for patients who are receiving one or more antiplatelet drugs. Despite this new knowledge, uncertainty remains as to best practices for the majority of perioperative management questions.

Emergent Reversal of Antithrombotics and Treatment of Life-Threatening Bleeding from Coagulopathies: A Clinical Review

BACKGROUND

Reversal of antithrombotic agents and treatment of life-threatening bleeding episodes from coagulopathies can be a stressful scenario for clinicians, especially when the selection of treatment options should occur quickly. Understanding the options available for these agents requires emergency physicians to be familiar with the current data surrounding new therapies and dosing strategies for the treatment of bleeding from reversible and nonreversible antithrombotics and coagulopathic conditions.

OBJECTIVE

To provide quick resource guides for the reversal of major or life-threatening bleeding caused by antithrombotic agents or in the setting of coagulopathies.

METHODS

A literature search for articles published through September 2021 related to antithrombotic reversal and treatment of acute bleeding from coagulopathies was conducted using the PubMed clinical database. Selected articles were used to generate 5 guidance tables in this clinical review.

DISCUSSION

Four guidance tables for how to treat major or life-threatening bleeding from antithrombotic agents and 1 table for how to manage life-threatening bleeding for coagulopathies are presented as a quick reference tool for the emergency physician. Additional information on upcoming reversal agents and possible treatment options are provided herein.

CONCLUSIONS

In this clinical review, a series of 5 tables were created to provide quick and comprehensive guidance for the emergency physician when treating major or life-threatening bleeding caused by antithrombotic agents or coagulopathies. © 2022 Elsevier Inc.

Pharmacologic Agents Used to Reverse the Anticoagulant Effect of Common Anticoagulants

Numerous oral and parenteral anticoagulant drugs are now available for clinical use. Understanding the precise pharmacologic properties of each anticoagulant is imperative for those practitioners who prescribe these drugs, including knowing the current recommendations for reversing the anticoagulant effect of each anticoagulant. This review provides a brief description of the various anticoagulants used today and also discusses the pharmacologic properties of those drugs used to reverse the anticoagulant action of specific anticoagulants.

INR Response to Low-Dose Vitamin K in Warfarin Patients

BACKGROUND

Literature suggests that 2 mg of vitamin K intravenously (IV) provides a similar effect as 10 mg to reverse warfarin. Doses <5 mg haven't been studied in depth.

OBJECTIVE

The objective was to determine the international normalized ratio (INR) reduction effect of ultra low-dose (ULD) IV vitamin K.

METHODS

This retrospective, observational cohort study compared IV vitamin K doses of 0.25-0.5 mg (ULD) versus 1-2 mg (standard low dose [SLD]). The primary outcome assessed ΔINR at 36 hours; secondary outcomes assessed ΔINR at 12 hours and 30-day venous thromboembolism (VTE) and mortality rates.

RESULTS

Of 88 patients identified (median baseline INR [IQR], 5.1 [3.1, 7.3] vs 4.5 [2.8, 8.2], ULD vs SLD, respectively), 59 had an INR at 12 hours. The ULD had fewer 12-hour INR values <2, with no statistical difference in the ΔINR at 12 hours between the ULD and SLD cohorts (median ΔINR, 2.2 [1.1, 3.4] vs 2.2 [1.1, 6.3]; P = 0.54; median INR, 2.3 vs 1.8). A total of 41 patients had both a 12- and 36-hour INR. No significant difference in the ΔINR between the 12- and 36-hour values occurred (median ΔINR, 0.52 [0.2, 0.91] vs ΔINR, 0.46 [0.18, 0.55]; P = 0.61), suggesting no rebound or excessive reversal and no difference in 30-day rates of VTE (P > 0.99) or death (P = 0.38).

CONCLUSION AND RELEVANCE

ULD IV vitamin K reversed INR similarly to doses of 1-2 mg without rebound. A ULD strategy may be considered in patients requiring more cautious reversal.

Effects of Obesity on Warfarin Reversal With Vitamin K

Phytonadione (vitamin K1, VK) is fat soluble and may be sequestered by adipose tissue, thus potentially altering drug distribution in obese patients requiring warfarin reversal. This single-center retrospective cohort study aimed to determine the effects of obesity (defined as body mass index [BMI] ≥ 30 kg/m²) on warfarin reversal following administration of VK in adult patients. The primary outcome was complete or partial warfarin reversal (defined as an international normalized ratio [INR] ≤ 2.0) within 72 hours post-VK administration. Of 688 identified patients, 215 were included in primary INR analysis. Mean BMIs for obese (n = 84) and nonobese (n = 131) patients were 37.3 and 24.3 kg/m² ( P < .001), and mean baseline INRs were 4.73 and 4.42 ( P = .534), respectively. Within 72 hours post-VK administration, 70% and 69% of the obese and nonobese groups, respectively, achieved complete or partial warfarin reversal ( P = .904). Multiple logistic regression determined baseline INR and concomitant fresh frozen plasma administration to be factors influencing warfarin reversal. These findings do not suggest obesity is significantly associated with a decreased likelihood of warfarin reversal within 72 hours post-VK administration.

Effect of vitamin K administration on rate of warfarin reversal

BACKGROUND

Vitamin K is reported to begin reversing warfarin within 6 to 12 hours, but this may occur sooner. We sought to determine the rate of international normalized ratio (INR) reversal following vitamin K and relationships with dose, route, and baseline INR.

METHODS

We evaluated adult patients receiving vitamin K monotherapy for warfarin reversal. Post-vitamin K INRs through 48 hours were collected. Relationships between vitamin K dose and route and baseline INR on rate of reversal and complete reversal (INR < 1.5) were evaluated. Assessment was performed graphically using scatter plots with a line of best fit and a counting process model to determine variables associated with achieving complete reversal.

RESULTS

A total of 469 post-vitamin K INRs from 235 patients were included. Time to first INR follow-up after vitamin K administration averaged 10.5 ± 4.2 hours. A significant decrease was detected in INR values in comparison to the baseline INR (3.0 ± 1.9 vs. 4.7 ± 2.2; p < 0.01). Rapid and steady INR change began immediately after vitamin K administration (0-4 hr). A high vitamin K dose and intravenous route were associated with rapid INR change and complete reversal (Vitamin K 10 mg [hazard ratio, 2.4; 95% confidence interval, 1.4-4.2] and IV route [hazard ratio, 1.8; 95% confidence interval, 1.3-2.6]); however, overall complete reversal at 24 and 48 hours was low (14.5% and 41.7%, respectively). Higher baseline INR was associated with rapid INR change and lower baseline INR with complete reversal.

CONCLUSION

Vitamin K alone starts to reverse warfarin immediately. High vitamin K doses and intravenous route are associated with faster INR reversal. Baseline INR also influences rate of correction and frequency of achieving complete reversal.

Management and outcome of major bleeding in patients receiving vitamin K antagonists for venous thromboembolism

BACKGROUND

The optimal management of major bleeding in patients receiving vitamin K antagonists (VKA) for venous thromboembolism (VTE) is unclear.

METHODS

We used the RIETE (Registro Informatizado Enfermedad TromboEmbólica) registry to assess the management and 30-day outcomes after major bleeding in patients receiving VKA for VTE.

RESULTS

From January 2013 to December 2017, 267 of 18,416 patients (1.4%) receiving long-term VKA for VTE had a major bleeding (in the gastrointestinal tract 78, intracranial 72, hematoma 50, genitourinary 20, other 47). Overall, 151 patients (57%) received blood transfusion; 110 (41%) vitamin K; 37 (14%) fresh frozen plasma; 29 (11%) pro-haemostatic agents and 20 (7.5%) a vena cava filter. During the first 30 days, 59 patients (22%) died (41 died of bleeding) and 13 (4.9%) had a thrombosis. On multivariable analysis, patients with intracranial bleeding (hazard ratio [HR]: 4.58; 95%CI: 2.40-8.72) and those with renal insufficiency at baseline (HR: 2.73; 95%CI: 1.45-5.15) had an increased mortality risk, whereas those receiving vitamin K had a lower risk (HR: 0.47; 0.24-0.92). On the other hand, patients receiving fresh frozen plasma were at increased risk for thrombotic events (HR: 4.22; 95%CI: 1.25-14.3).

CONCLUSIONS

Major bleeding in VTE patients receiving VKA carries a high mortality rate. Intracranial bleeding and renal insufficiency increased the risk. Fresh frozen plasma seems to increase this risk for recurrent VTE.

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.

Four-factor prothrombin complex concentrate for life-threatening bleeds or emergent surgery: A retrospective evaluation

PURPOSE

Previous trials investigating usage of four-factor prothrombin complex concentrate (4F-PCC) excluded patients with various thrombotic risk factors. The objective of this study was to evaluate the safety and effectiveness of 4F-PCC in a real-world setting based on an institutional protocol that does not have strict exclusion criteria.

METHODS

This was a retrospective study of adult patients who received 4F-PCC. The primary outcome was a confirmed thromboembolism within 14 days after 4F-PCC administration. Secondary outcomes included international normalized ratio (INR) correction to <1.5 at first draw and incidence of INR rebound for patients undergoing reversal of warfarin and hemostatic effectiveness for patients experiencing a bleed.

RESULTS

Ninety-three patients received 4F-PCC. Sixty-three (67.7%) were reversed for bleeding and 30 (32.3%) for surgery. Eleven patients (11.8%) developed a thromboembolism within 14 days. The median (interquartile range) time to event was 5 (2-7) days. Significant risk factors were heparin-induced thrombocytopenia (P= .01) and major surgery within 14 days (P= .02), as well as the presence of >6 thrombotic risk factors (P= .01). For patients post-warfarin reversal, 45/63 (71.4%) achieved INR correction at first draw, 55/63 (87.3%) achieved INR correction within 24 hours, and 14/55 (25.5%) experienced INR rebound. Of these 14 patients, 8 (57.1%) did not receive concomitant vitamin K.

CONCLUSIONS

4F-PCC was associated with a notable thromboembolic risk. All patient-specific risk factors should be considered prior to administration. 4F-PCC remains a useful agent for warfarin reversal. Lack of concomitant vitamin K may contribute to INR rebound.

Establishing a rat model for the study of vitamin K deficiency

The main vitamin K-deficient model, minidose warfarin, is different from the pathological mechanism of vitamin K deficiency, which is a shortage of vitamin K. The objective of this study was to establish a new method of vitamin K-deficient model combining a vitamin K-deficient diet with the intragastrical administration of gentamicin in rats. The clotting was assayed by an automated coagulation analyser. The plasma PIVKA-II was assayed by ELISA. The vitamin K status was detected by an HPLC-fluorescence system. In the diet- and gentamicin-induced vitamin K-deficient 14-day group, the rats had undetected vitamin K1 and vitamin K2 in the liver and a prolonged APTT. In the 21-day group, there was also a prolonged PT and a decrease of the FIX activities. In the 28-day group, the undetected vitamin K1 and vitamin K2, the prolonged PT and APTT, and the decrease of the FII, FVII, FIX, and FX activities prompted the suggestion that there were serious deficiencies of vitamin K and vitamin K-dependent coagulation in rats. It is suggested that the diet- and gentamicin-induced vitamin K-deficient 14-day or 21-day model can be used for studies related to the status of vitamin K. The vitamin K-deficient 28-day model can be applied to research involving both the status of vitamin K and of vitamin K-dependent coagulation. In conclusion, the combination of a vitamin K-deficient diet with the administration of gentamicin results in a useful model of vitamin K-deficieny.

Rapid Anticoagulation Reversal With Prothrombin Complex Concentrate Before Emergency Brain Tumor Surgery

BACKGROUND

Brain tumors may become symptomatic due to intracranial hypertension and patients may present to emergency departments in life-threatening conditions. Hence, emergency brain tumor surgery has to be considered, but sufficient hemostasis has to be present when initiating surgical procedures. Impaired hemostasis because of oral anticoagulation for the treatment of cardiovascular diseases is encountered in a growing number of patients. Here we present the first case series of anticoagulated patients receiving prothrombin complex concentrate (PCC) to rapidly restore hemostasis and facilitate emergency brain tumor surgery.

METHODS

We retrospectively analyzed our institutional database of neurosurgical patients receiving PCC from February 2007 to April 2013 (n=432) and identified 5 patients who received PCC before emergency brain tumor surgery. Clinical characteristics, as well as modalities of PCC administration and parameters of hemostasis were analyzed.

RESULTS

Patients had a mean Glasgow Coma Scale score of 9.4 at admission. Mean international normalized ratio was 3.75±1.98 and after administration of PCC (mean, 3260±942 IU), international normalized ratio significantly decreased to 1.19±0.07 (P<0.0001). Emergency brain tumor surgery was initiated within 5.2 hours (range, 0 to 13.5 h) after PCC administration. Diagnostic histopathology revealed metastasis (n=2), meningioma (n=2), and ependymoma (n=1). No hemorrhagic or thromboembolic events occurred and 4 patients had a good neurological outcome at hospital discharge. One patient died on the 14th postoperative day because of respiratory failure following development of pneumonia.

CONCLUSIONS

In anticoagulated patients with brain tumors requiring immediate surgery due to life-threatening conditions, administration of PCC rapidly and safely restored hemostasis. PCC administration seems to be an effective option for anticoagulant reversal in this patient cohort. Further observational safety studies (eg, thromboembolic events) are warranted.

Fast-track rapid warfarin reversal for elective surgery: extending the efficacy profile to high-risk patients with cancer

Periprocedural management of patients on long-term warfarin therapy remains a common and important clinical issue, with little high-quality data to guide this complex process. The current accepted practice is cessation of warfarin five days preoperatively, but this is not without risk and can be complicated, particularly if bridging is required. An alternative method utilising low-dose intravenous vitamin K the day before surgery has been shown previously to be efficacious, safe and convenient in an elective surgical population receiving chronic warfarin therapy. The efficacy and utility of this 'fast-track' warfarin reversal protocol in surgical patients with cancer, who were at high risk of both thromboembolism and bleeding was investigated in a prospective, single-arm study at a dedicated cancer centre. Seventy-one patients underwent 82 episodes of fast-track warfarin reversal (3 mg intravenous vitamin K 18 to 24 hours before surgery). No patient suffered an adverse reaction to intravenous vitamin K, all but one achieved an International Normalized Ratio =1.5 on the day of surgery, and no surgery was deferred. Assays of vitamin K-dependent factor levels pre- and post-vitamin K demonstrated restoration of functional activity to within an acceptable range for surgical haemostasis. While this alternative method requires further validation in a larger prospective randomised study, we have now extended our use of fast-track warfarin reversal using vitamin K to patients with cancer, on the basis of our experience of its safety, convenience, reliability and efficacy.

"Early Trigger" Intravenous Vitamin K: Optimizing Target-Driven Care in Warfarinised Patients With Hip Fracture

Best practice tariff (BPT) was introduced as a financial incentive model to improve compliance with evidence-based care, such as operation for hip fracture within 36 hours of admission. We previously evaluated the impact of warfarin on patients with hip fracture, revealing significant delay to operation and subsequent loss of revenue. As a result of this, an “early trigger” intravenous vitamin K (IVK) pathway was introduced and the service reaudited a year later. The first cycle was a retrospective audit of all cases with hip fracture against BPT standards over a 32-month period. Subsequent protocol change resulted in all warfarinised cases being given 2 mg IVK in the emergency department prior to blood testing. This protocol was reaudited against the same BPT standards 12 months later. An intention-to-treat approach was used, despite breaches of protocol and other reasons for patients not progressing to theater. The data were analyzed with parametric tools to establish true clinical and statistical impact of the introduction of the protocol. In the first cycle, 80 patients were admitted on warfarin with a mean time to theater of 53.71 hours. Of these patients, 79% breached BPT due to anticoagulation. Twelve months following protocol introduction, 42 patients had a mean time to theater of 37.61 hours. Of these patients, 34% breached BPT due to anticoagulation. These data are both clinically and statistically significant (P < .001). No adverse events occurred. We have shown for the first time that “early-trigger” IVK can reduce delay to theater and maximize tariff payments in warfarinised patients with hip fracture. This is in addition to other established benefits associated with early surgery such as decreasing risk of pressure lesions and pneumonia. It affords high-quality patient-centered care while ensuring trauma units achieve maximal financial reimbursement through pay for improved performance and supports a culture of change behavior.

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.

Management of bleeding and reversal strategies for oral anticoagulants: clinical practice considerations

PURPOSE

Currently available clinical data and optimal strategies for reversing oral anticoagulants in patients who are bleeding or need an urgent invasive procedure or operation are reviewed.

SUMMARY

Bleeding from oral anticoagulants, including new target-specific oral agents (TSOAs), is a common cause of morbidity and mortality, especially in elderly patients. Limited clinical data are available to guide the reversal of warfarin or TSOAs in patients who are bleeding or need an urgent invasive procedure or operation. A panel of five experts with diverse backgrounds in anticoagulation therapy, cardiology, critical care, and emergency medicine and with experience in managing complications of anticoagulation therapy was convened to develop practical strategies for managing patients receiving oral anticoagulants who are bleeding or have an urgent need for an invasive procedure. The strategies were designed to guide clinicians in the acute care setting by providing efficient and potentially effective management concepts to avoid delays in initiating treatment that could adversely affect patient outcomes. The consensus of this expert panel is summarized herein. Recommendations are based on currently available evidence from a comprehensive review of the literature and other pertinent data, along with the experience and expert opinion of the panelists.

CONCLUSION

Bleeding is a serious complication of the use of oral anticoagulants, and limited information is available to guide the reversal of warfarin or TSOAs in patients who are bleeding or are in need of an urgent invasive procedure. Use of a systematic approach to assessing and treating these patients based on available evidence and expert opinion can help avoid delays that could adversely affect patient outcomes.

Prothrombin complex concentrate facilitates emergency spinal surgery in anticoagulated patients

BACKGROUND

Oral anticoagulants are commonly used in the ageing population and therefore, spine surgeons are increasingly confronted with anticoagulated patients requiring surgical therapy. 'Bridging therapies' with heparins are established in elective settings, but the time frame for haemostasis restoration may be too long for patients presenting with acute spinal pathology and impending disability. The goal of this study was to analyse the feasibility of prothrombin complex concentrate (PCC) administration to facilitate emergency spinal surgery in anticoagulated patients.

METHOD

A retrospective analysis of the institutional database of neurosurgical patients receiving PCC from February 2007 to December 2013 (n = 485) identified 18 patients who received PCC prior to emergency spinal surgery. Clinical characteristics, as well as modalities of PCC administration and parameters of haemostasis were analysed. Furthermore, haemorrhagic complications and thromboembolic events in the further course were evaluated.

RESULTS

Spinal pathologies requiring urgent neurosurgical decompression were spinal haematoma (n = 9), spinal metastasis (n = 5), vertebral body fracture (n = 2), and disc herniation (n = 2). The mean international normalized ratio (INR) on admission was 2.27 ± 1.20 and after administration of PCC (mean: 1,944 ± 953 I.U.), INR significantly decreased to 1.12 ± 0.10 (p < 0.001). Emergency surgery was initiated within 4.4 h after PCC administration (range: 0-16.6 h). Postoperatively, symptoms improved in 12 patients (66.7 %). There were two deaths (11 %), one caused by acute myocardial infarction on the fourth postoperative day. Bleeding complications occurred in two patients (epidural haemorrhage n = 1, rectal tumour haemorrhage n = 1).

CONCLUSIONS

The administration of PCC facilitates emergency spinal surgery in anticoagulated patients who present with acute spinal pathology requiring urgent neurosurgical decompression. The risk of PCC-associated thromboembolic events seems to be low and justifies the use of PCC in order to avoid permanent disablement resulting from delayed surgery or non-operation.