Clinical predictors of prolonged delay in return of the international normalized ratio to within the therapeutic range after excessive anticoagulation with warfarin

Top 25 Medications the Plastic and Reconstructive Surgery Trainee Should Know for an Emergency Medicine Department Consult

SUMMARY

Plastic surgery trainees are often called to render care in the emergency department (eg, for established patients, trauma, burns). Broad-based knowledge in pharmacotherapeutics during these encounters is critical. This includes an understanding of pain medications, anxiolytics, local anesthetics, antibiotics, anticoagulants, antidotes, and more to ensure optimal patient care. The purpose of this report is to describe 25 frequently used and other important medications that plastic surgery trainees should know for an adult emergency department encounter.

New insights into the role of VKORC1 polymorphisms for optimal warfarin dose selection in Caribbean Hispanic patients through an external validation of a population PK/PD model

Warfarin, an oral anticoagulant, has been used for decades to prevent thromboembolic events. The complex interplay between CYP2C9 and VKORC1 genotypes on warfarin PK and PD properties is not fully understood in special sub-groups of patients. This study aimed to externally validate a population pharmacokinetic/pharmacodynamic (PK/PD) model for the effect of warfarin on international normalized ratio (INR) and to evaluate optimal dosing strategies based on the selected covariates in Caribbean Hispanic patients. INR, and CYP2C9 and VKORC1 genotypes from 138 patients were used to develop a population PK/PD model in NONMEM. The structural definition of a previously published PD model for INR was implemented. A numerical evaluation of the parameter-covariate relationship was performed. Simulations were conducted to determine optimal dosing strategies for each genotype combinations, focusing on achieving therapeutic INR levels. Findings revealed elevated IC50 for G/G, G/A, and A/A VKORC1 haplotypes (11.76, 10.49, and 9.22 mg/L, respectively), in this population compared to previous reports. The model-guided dosing analysis recommended daily warfarin doses of 3-5 mg for most genotypes to maintain desired INR levels, although subjects with combination of CYP2C9 and VKORC1 genotypes * 2/* 2-, * 2/* 3- and * 2/* 5-A/A would require only 1 mg daily. This research underscores the potential of population PK/PD modeling to inform personalized warfarin dosing in populations typically underrepresented in clinical studies, potentially leading to improved treatment outcomes and patient safety. By integrating genetic factors and clinical data, this approach could pave the way for more effective and tailored anticoagulation therapy in diverse patient groups.

Perioperative Management of Anticoagulant and Antiplatelet Therapy

Anticoagulant and Antiplatelet Drug ManagementManagement of patients on an anticoagulant or antiplatelet drug who require surgery or an invasive procedure is a common clinical problem. Douketis and Spyropoulos provide an evidence-based but practical approach to managing anticoagulants and antiplatelet drugs in the perioperative setting.

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.

A Historical Perspective on the Reversal of Anticoagulants

There has been a landmark shift in the last several decades in the management and prevention of thromboembolic events. From the discovery of parenteral and oral agents requiring frequent monitoring as early as 1914, to the development of direct oral anticoagulants (DOACs) that do not require monitoring or dose adjustment in the late 20th century, great advances have been achieved. Despite the advent of these newer agents, bleeding continues to be a key complication, affecting 2 to 4% of DOAC-treated patients per year. Bleeding is associated with substantial morbidity and mortality. Although specific reversal agents for DOACs have lagged the release of these agents, idarucizumab and andexanet alfa are now available as antagonists. However, the efficacy of these reversal agents is uncertain, and complications, including thrombosis, have not been adequately explored. As such, guidelines continue to advise the use of nonspecific prohemostatic agents for patients requiring reversal of the anticoagulant effect of these drugs. As the indications for DOACs and the overall prevalence of their use expand, there is an unmet need for further studies to determine the efficacy of specific compared with nonspecific pro-hemostatic reversal agents. In this review, we will discuss the evidence behind specific and nonspecific reversal agents for both parenteral and oral anticoagulants.

Electrochemical Sensor for the Direct Determination of Warfarin in Blood

Detecting warfarin levels in the blood is of critical importance in anticoagulant therapy because it is imperative that the concentration of the drug is maintained within a specific range. In this paper, we present a proof-of-concept of a novel sensing device based on ion-selective electrode (ISE) technology for the direct detection of warfarin in blood samples without any sample pretreatment. We used tetradodecylammonium chloride (TDDA) as an ion-exchanger to fabricate an ion-selective membrane. The ISE we developed showed high sensitivity, with a limit of detection (LOD) of 1.25 × 10−7 M and 1.4 × 10−5 M for detecting warfarin in buffer and blood, respectively. The sensor also exhibited promising selectivity in identifying the presence of various ions including chloride and salicylate, the most abundant ions in blood with a calibration slope of 58.8 mV/dec. We envision combining the ISE with a microfluidic system and a simple potentiometer to produce a sensitive, selective, and portable point-of-care testing device for monitoring the level of warfarin in patients’ blood during treatment.

Prevalence and management of antivitamin K overdose in a hospital setting

INTRODUCTION

Vitamin K antagonist (VKA) related adverse events are the first cause for iatrogenic events in France, particularly due to the narrow therapeutic margin. The risk of bleeding increases significantly when the INR level is ≥5. The main objective of this study was to assess the prevalence of VKA overdose in a hospital setting (at D2 of hospital entry) and to evaluate physicians' adherence to clinical practice guidelines for the management of VKA overdose according to French National Authority for Health recommendations.

METHODS

This single-center retrospective observational study consisted in querying the computerized database of a Parisian hospital on 21275INR determinations (3995 patients, 6813 hospital stays) performed between 2013 and 2018.

RESULTS

An INR level ≥5 was noted during 350 (6%) of the hospital stays, in 331 patients (of whom 57% were women). The mean age of the patient population with an INR≥5 was 81.1 years. Infection, heart failure and renal failure were the most frequent acute medical conditions for hospital admission. Twenty-three patients (7%) had a bleeding complication, 11 of which were major bleeding complications. Older age was associated with the severity of bleeding complications. Fifteen in-hospital deaths (4%) were reported, not related to bleeding events. The management of VKA overdose did not comply with the recommendations in 43% of cases, in particular for the highest INRs (50% of noncompliance for an INR>6.4). Non-compliance with recommendations for VKA overdose was related to: the delay until the INR was checked (44% of cases); the indication for prescribing vitamin K (34% of cases); the dose or route of administration of vitamin K therapy (19% of cases); and the interruption or not of VKA therapy (12% of cases).

CONCLUSION

The management of VKA overdose in a hospital setting remains non-compliant with the recommendations in almost half of the cases, mainly due to the delayed INR control and inappropriate management of vitamin K therapy. Computerized alert system would be helpful for personalized patient management and improved pharmacovigilance to prevent iatrogenic VKA events.

Development of an Institutional Periprocedural Management Guideline for Oral Anticoagulants

Patients on oral anticoagulation commonly undergo surgery or other invasive procedures. Periprocedural management of oral anticoagulants involves a careful balance of the thromboembolic risk and bleeding risk. To standardize clinical practice at our institution, we developed a guideline for periprocedural management for patients taking oral anticoagulants that incorporates published data and expert opinion. In this article, we present our clinical practice guideline as a decision support tool to aid clinicians in developing a consistent strategy for managing periprocedural anticoagulation and for safely bridging anticoagulation in patients who require it.

Real-life Performance of Edoxaban in Elderly Patients With Atrial Fibrillation: a Multicenter Propensity Score-Matched Cohort Study

PURPOSE

The purpose of the current study was to compare the efficacy and safety of edoxaban versus vitamin K antagonist (VKA) therapy among a cohort of elderly patients (ie, those aged ≥75 years) with atrial fibrillation (AF) in a real-life setting.

METHODS

A propensity score-matched cohort observational study was performed comparing the safety and efficacy of edoxaban versus VKA therapy among a cohort of elderly (aged ≥75 years) patients with AF in a real-life setting. Follow-up data were obtained through outpatient visits at 1, 3, and every 6 months. The primary safety outcome was major bleeding. The primary efficacy outcome was the composite of stroke, transient ischemic attack, and systemic embolism.

FINDINGS

A total of 130 patients receiving edoxaban 60 mg (EDO) treatment were compared with the same number of VKA recipients. The mean follow-up was 16 (2.6) months. The cumulative incidence of thromboembolic events in the EDO and VKA groups was 1.5% (2 of 130) and 2.3% (3 of 130), respectively (P < 0.6). The cumulative incidence of major bleeding events was 1.5% (2 of 130) in the EDO group and 3.1% (4 of 130) in the VKA group (P < 0.4). The total anticoagulant therapy discontinuation rate was 2.3% (3 of 130) in the EDO group and 4.6% (6 of 130) in the VKA group (P < 0.3). A nonsignificant trend in improved adherence was observed between the EDO and VKA groups (81% vs 78%; P = 0.6).

IMPLICATIONS

Edoxaban therapy showed a good real-life performance among elderly patients (aged ≥75 years) with AF.

International normalized ratio on admission predicts the 90-day mortality of critically ill patients undergoing endarterectomy

The association of the international normalized ratio (INR) with the long-term clinical outcome of patients who undergo endarterectomy has not yet been studied. The present study therefore primarily aimed to evaluate the association of INR on admission with the 90-day mortality of critically ill patients who underwent endarterectomy during hospitalization. The Medical Information Mart for Intensive Care III database was queried for patients undergoing endarterectomy. The 90-day mortality of patients was selected as a primary endpoint. Receiver-operating characteristic (ROC) curves were plotted to present the accuracy of predictions. Kaplan-Meier curves and multivariate Cox regression analysis were performed to analyse associations. Propensity score matching (PSM) was also conducted to reduce confounding bias. A total of 230 patients were included, with 36 90-day non-survivors. Patients with a high INR (≥1.5) on admission exhibited a higher 90-day mortality than those with a low INR (<1.5; 29.09 vs. 11.43%; P=0.003). The ROC area under the curve value was 0.687 [95% confidence interval (CI), 0.571–0.780]. Kaplan-Meier plots identified divergence in survival between patients with different INR levels (log-rank test, P=0.0013). The results of the multivariate Cox regression analysis indicated that a high INR level was significantly associated with 90-day mortality (hazard ratio, 2.19; 95% CI, 1.08–4.45; P=0.0305). Analysis of the PSM cohort presented similar results. In conclusion, the INR levels of critically ill patients who undergo endarterectomy may be used to stratify their risk of 90-day mortality.

Prothrombin complex concentrate versus placebo, no intervention, or other interventions in critically bleeding patients associated with oral anticoagulant administration: a protocol for a systematic review of randomised clinical trials with meta-analysis and trial sequential analysis

BACKGROUND

Acute critical bleeding is one of the most feared complications during treatment with oral anticoagulating agents. As more patients undergo treatment with anticoagulating agents, critically bleeding episodes in patients with vitamin K antagonists, thrombin inhibitor, or factor Xa inhibitor-inducted coagulopathy will be encountered frequently by physicians. Hence, an effective treatment capable of reversing the iatrogenic coagulopathy in the acute setting is needed. In randomised clinical trials and observational studies, prothrombin complex concentrate has been reported to be superior to other acute interventions, and many guidelines recommend prothrombin complex concentrate in treatment of critically bleeding patients. The aim of this systematic review is to synthesise the evidence of the effects of prothrombin complex concentrate compared with placebo, no intervention, or other treatment options in critically bleeding patients treated with oral anticoagulants.

METHODS/DESIGN

A comprehensive search for relevant published literature will be undertaken in Cochrane Central Register of Controlled Trials, MEDLINE, Embase, WHO International Clinical Trials Registry Platform, Science Citation Index, regulatory databases, and trial registers. We will include randomised clinical trials comparing prothrombin complex concentrate versus placebo, no intervention, or other interventions in critically bleeding patients with oral anticoagulant-induced coagulopathy. Data extraction and risk of bias assessment will be handled by two independent review authors. Meta-analysis will be performed as recommended by Cochrane Handbook for Systematic Reviews of Interventions, bias will be assessed with domains, and trial sequential analysis will be conducted to control random errors. Certainty will be assessed by GRADE.

DISCUSSION

As critical bleeding in patients treated with oral anticoagulants is an increasing problem, an up-to-date systematic review evaluating the benefits and harms of prothrombin complex concentrate is urgently needed. It is the hope that this review will be able to guide best practice in treatment and clinical research of these critically bleeding patients.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018084371.

Impact of incorporating ABCB1 and CYP4F2 polymorphisms in a pharmacogenetics-guided warfarin dosing algorithm for the Brazilian population

PURPOSE

Interpatient variation of warfarin dose requirements may be explained by genetic variations and general and clinical factors. In this scenario, diverse population-calibrated dosing algorithms, which incorporate the main warfarin dosing influencers, have been widely proposed for predicting supposed warfarin maintenance dose, in order to prevent and reduce adverse events. The aim of the present study was to evaluate the impact of the inclusion of ABCB1 c.3435C>T and CYP4F2 c.1297G>A polymorphisms as additional covariates in a previously developed pharmacogenetic-based warfarin dosing algorithm calibrated for the Brazilian population.

METHODS

Two independent cohorts of patients treated with warfarin (n = 832 and n = 133) were included for derivation and replication of the algorithm, respectively. Genotyping of ABCB1 c.3435C>T and CYP4F2 c.1297G>A polymorphisms was performed by polymerase chain reaction followed by melting curve analysis and TaqMan® assay, respectively. A multiple linear regression was performed for the warfarin stable doses as a dependent variable, considering clinical, general, and genetic data as covariates.

RESULTS

The inclusion of ABCB1 and CYP4F2 polymorphisms was able to improve the algorithm's coefficient of determination (R²) by 2.6%. In addition, the partial determination coefficients of these variants revealed that they explained 3.6% of the warfarin dose variability. We also observed a marginal improvement of the linear correlation between observed and predicted doses (from 59.7 to 61.4%).

CONCLUSION

Although our study indicates that the contribution of the combined ABCB1 and CYP4F2 genotypes in explaining the overall variability in warfarin dose is not very large, we demonstrated that these pharmacogenomic data are statistically significant. However, the clinical relevance and cost-effective impact of incorporating additional variants in warfarin dosing algorithms should be carefully evaluated.

Incidence and Determinants of Traumatic Intracranial Bleeding Among Older Veterans Receiving Warfarin for Atrial Fibrillation

IMPORTANCE

Traumatic intracranial bleeding, which is most commonly attributable to falls, is a common concern among health care professionals, who are hesitant to prescribe oral anticoagulants to older adults with atrial fibrillation.

OBJECTIVE

To describe the incidence of and risk factors for traumatic intracranial bleeding in a large cohort of older adults who were newly prescribed warfarin sodium.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study at the US Department of Veterans Affairs (VA). Participants included 31 951 veterans with atrial fibrillation 75 years or older who were new referrals to VA anticoagulation clinics (for warfarin therapy) between January 1, 2002, and December 31, 2012. The dates of the core analysis were March 2014 through May 2015, and subsequent ad hoc analyses were performed through December 2015. Patients with comorbid conditions requiring warfarin were excluded.

MAIN OUTCOMES AND MEASURES

The primary outcome was hospitalization for traumatic intracranial bleeding. Secondary outcomes included hospitalization for any intracranial bleeding or ischemic stroke. We used International Classification of Diseases, Ninth Revision, Clinical Modification codes to identify the incidence rates of these outcomes after warfarin initiation using VA administrative data (in-system hospitalizations) and Medicare fee-for-service claims data (out-of-system hospitalizations). Clinical characteristics, laboratory results, and pharmacy data were extracted from the VA electronic medical record. For traumatic intracranial bleeding, Cox proportional hazards regression was used to determine predictors of interest selected a priori based on prior known associations.

RESULTS

The study population comprised 31 951 participants. The mean (SD) patient age was 81.1 (4.1) years, and 98.1% were male. Comorbidities were common, including hypertension (82.5%), coronary artery disease (42.6%), and diabetes mellitus (33.8%). During the study period, the incidence rate of hospitalization for traumatic intracranial bleeding was 4.80 per 1000 person-years. In unadjusted models, significant predictors of traumatic intracranial bleeding included dementia, fall within the past year, anemia, depression, abnormal renal or liver function, anticonvulsant use, labile international normalized ratio, and antihypertensive use. After adjusting for potential confounders, the remaining significant predictors for traumatic intracranial bleeding were dementia (hazard ratio [HR], 1.76; 95% CI, 1.26-2.46), anemia (HR, 1.23; 95% CI, 1.00-1.52), depression (HR, 1.30; 95% CI, 1.05-1.61), anticonvulsant use (HR, 1.35; 95% CI, 1.04-1.75), and labile international normalized ratio (HR, 1.33; 95% CI, 1.04-1.72). The incidence rates of hospitalization for any intracranial bleeding and ischemic stroke were 14.58 and 13.44, respectively, per 1000 person-years.

CONCLUSIONS AND RELEVANCE

Among patients 75 years or older with atrial fibrillation initiating warfarin therapy, the risk factors for traumatic intracranial bleeding are unique from those for ischemic stroke. The high overall rate of intracranial bleeding in our sample supports the need to more systematically evaluate the benefits and harms of warfarin therapy in older adults.

Management of oral antiplatelet agents and anticoagulation therapy before bronchoscopy

Although, bronchoscopy is a relatively safe procedure, small amount of bleeding in the airway can have serious consequences. Careful consideration of the risks of diagnostic and therapeutic bronchoscopic intervention can help minimize potential complications. With increasing number of patients using antiplatelet and anticoagulation therapies, strategies for minimizing thromboembolic and operative bleeding events need to be included in the risk and benefit analyses. Growing evidence suggests that aspirin is safe and does not increase bleeding during bronchoscopy. In addition, despite small studies reporting that it may be safe to perform bronchoscopic procedures that have low risk for bleeding such as endobronchial ultrasound with transbronchial needle aspiration on clopidogrel, it is still recommended to hold it for 7 days prior to performing elective bronchoscopy. It is recommended to hold vitamin K antagonist, as well as new oral anticoagulation agents prior to bronchoscopy. The timing for pre-procedural discontinuation of anticoagulation therapy and the decision to bridge depend on the agent used, the renal function and the thromboembolic risk. In this review article, we will discuss available data regarding management of anticoagulation and antiplatelet therapy as it applies to bronchoscopic procedures.

Assessment of the efficacy of a novel tailored vitamin K dosing regimen in lowering the International Normalised Ratio in over-anticoagulated patients: a randomised clinical trial

Current guidelines advocate using fixed-doses of oral vitamin K to reverse excessive anticoagulation in warfarinised patients who are either asymptomatic or have minor bleeds. Over-anticoagulated patients present with a wide range of International Normalised Ratio (INR) values and response to fixed doses of vitamin K varies. Consequently a significant proportion of patients remain outside their target INR after vitamin K administration, making them prone to either haemorrhage or thromboembolism. We compared the performance of a novel tailored vitamin K dosing regimen to that of a fixed-dose regimen with the primary measure being the proportion of over-anticoagulated patients returning to their target INR within 24 h. One hundred and eighty-one patients with an index INR > 6·0 (asymptomatic or with minor bleeding) were randomly allocated to receive oral administration of either a tailored dose (based upon index INR and body surface area) or a fixed-dose (1 or 2 mg) of vitamin K. A greater proportion of patients treated with the tailored dose returned to within target INR range compared to the fixed-dose regimen (68·9% vs. 52·8%; P = 0·026), whilst a smaller proportion of patients remained above target INR range (12·2% vs. 34·0%; P < 0·001). Individualised vitamin K dosing is more accurate than fixed-dose regimen in lowering INR to within target range in excessively anticoagulated patients.

Incidence and predictors of excessive warfarin anticoagulation in patients with atrial fibrillation-The EWA study

Vitamin K antagonist warfarin is widely used in clinical practice and excessive anticoagulation is a well-known complication of this therapy. Little is known about permanent and temporary predictors for severe overanticoagulation. The aim of this study was to investigate the occurrence and predicting factors for episodes with very high (≥9) international normalized ratio (INR) values in warfarin treated patients with atrial fibrillation (AF). Excessive Warfarin Anticoagulation (EWA) study screened all patients (n = 13618) in the Turku University Hospital region with an INR ≥2 between years 2003–2015. Patients using warfarin anticoagulation for AF with very high (≥9) INR values (EWA Group) were identified (n = 412 patients) and their characteristics were compared to a control group (n = 405) of AF patients with stable INR during long-term follow-up. Over 20% (n = 92) of the EWA patients had more than one event of very high INR and in 105 (25.5%) patients EWA led to a bleeding event. Of the several temporary and permanent EWA risk factors observed, strongest were excessive alcohol consumption in 9.6% of patients (OR 24.4, 95% CI 9.9–50.4, p<0.0001) and reduced renal function (OR 15.2, 95% CI 5.67–40.7, p<0.0001). Recent antibiotic or antifungal medication, recent hospitalization or outpatient clinic visit and the first 6 months of warfarin use were the most significant temporary risk factors for EWA. Excessive warfarin anticoagulation can be predicted with several permanent and temporary clinical risk factors, many of which are modifiable.

Management of Atrial Fibrillation in Elderly Adults

Driven in large part by the aging of the population and the increasing prevalence of cardiovascular comorbidities associated with atrial fibrillation (AF), there is a burgeoning epidemic of AF in elderly adults. Although there is a large body of literature to guide management of people with AF, elderly adults with AF are frequently underrepresented in clinical trials. This review provides a contemporary update on management of elderly adults with AF with a particular focus on the two main clinical challenges that AF poses: stroke risk reduction and control of symptoms. The evidence to support novel AF treatment strategies in elderly adults is reviewed, including novel oral anticoagulants and left atrial appendage closure for stroke risk reduction and catheter ablation for control of symptoms.

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.

Administration of Coagulation-Altering Therapy in the Patient Presenting for Oral Health and Maxillofacial Surgery

Oral health care providers are concerned with how to manage patients prescribed coagulation-altering therapy during the perioperative/periprocedural period for dental and oral surgery interventions. Management and recommendation can be based on medication pharmacology and the clinical relevance of coagulation factor levels/deficiencies. Caution should be used with concurrent use of medications that affect other components of the clotting mechanisms; prompt diagnosis and any necessary intervention to optimize outcome is warranted. However, evidence-based data on management of anticoagulation therapy during oral and maxillofacial surgery/interventions is lacking. Therefore, clinical understanding and judgment are needed along with appropriate guidelines matching patient- and intervention-specific recommendations.

Evaluation of Warfarin Reversal with 4-Factor Prothrombin Complex Concentrate Compared to 3-Factor Prothrombin Complex Concentrate at a Tertiary Academic Medical Center

BACKGROUND

The U.S. Food and Drug Administration recently approved a four-factor prothrombin complex concentrate (4-PCC) for warfarin reversal. The literature supporting its use over three-factor prothrombin complex concentrate (3-PCC) is limited.

OBJECTIVE

Our objective was to retrospectively compare the efficacy of 3-PCC to 4-PCC in reversing warfarin in patients who were actively bleeding.

METHODS

We conducted a single-center, retrospective cohort analysis of adult patients who received 3-PCC or 4-PCC for international normalized ratio (INR) reversal. Our study excluded patients not actively bleeding and not on warfarin. The main outcome was the percentage of patients who achieved warfarin reversal defined as INR ≤ 1.3 at first INR check post factor administration. We recorded baseline data including PCC dose, location of bleed, pre- and posttreatment INR, and time to INR reversal.

RESULTS

We included a total of 53 patients. Intracranial hemorrhage was the most common site of bleeding (26 [74.3%] in 3-PCC vs. 12 [66.7%] in 4-PCC). The mean dose of 3-PCC was 25.5 units/kg, compared to 27.9 units/kg of 4-PCC. The mean baseline INR was 2.3 in the 3-PCC group and 3 in the 4-PCC group (p = 0.03), and the first posttreatment INRs were 1.4 and 1.2, respectively (p < 0.01). Warfarin reversal was achieved in 15 (42.9%) patients who received 3-PCC and 15 (83.3%) patients who received 4-PCC (p < 0.01). Faster time to INR reversal was noted in the 4-PCC group vs. the 3-PCC group (3.7 vs. 5 h, p = 0.48).

CONCLUSION

A higher percentage of patients achieved warfarin reversal with 4-PCC compared to 3-PCC treatment. A prospective randomized control trial is necessary to confirm our results.

Validity of Criteria Used to Evaluate Fingerstick Devices That Assess International Normalized Ratio

Background . Investigators commonly rely on unvalidated, mainly arithmetic criteria to predict if point-of-care fingerstick devices that assess International Normalized Ratio (INR) lead to the same warfarin dosing decisions as a standard measure. Methods . Criteria that predict warfarin dosing agreement between 2 INR measurements were evaluated using clinicians’ actual dosing decisions as the standard. Bayesian hierarchical modeling was used to rank the criteria by the proportion of correct dosing predictions and the magnitude of difference between actual and predicted dosing agreement. Results . The prediction criteria misclassified dosing agreement for between 19% and 38% of paired INR values (x̄x: 27%). The magnitude of misclassification varied inconsistently throughout the INR scale. Conclusion . The unvalidated criteria used to predict warfarin dosing agreement between 2 INR measurements are associated with large error. Warfarin dosing decisions should be measured directly in such assessments.

Analysis of the first therapeutic-target-achieving time of warfarin therapy and associated factors in patients with pulmonary embolism

The present study aimed to investigate the factors affecting the first therapeutic-target-achieving (TTA) time of warfarin therapy in patients with acute pulmonary embolism (PTE). Between January 2008 and June 2013, patients with PTE confirmed by transpulmonary arterial enhanced computed tomographic pulmonary angiography or pulmonary ventilation perfusion scanning were included in the present study. Data collected included demographic information, history of tobacco and alcohol intake, basic diseases (stable and unstable hypertension, diabetes, heart failure, cancer/cerebral infarction, old myocardial infarction and atrial fibrillation), liver and kidney function, the haemoglobin and platelet count of the blood, international normalized ratio monitoring, warfarin dosage adjustment and medication combinations. Dynamic changes in international normalized ratio, anticoagulant efficacy, and adverse events within 90 days were monitored and analyzed. Univariate analysis demonstrated that the following factors affect the first TTA time: Initial dose, body mass index (BMI), liver function, heart failure, and the administration of levofloxacin, cephalosporins, and blood circulation-activating drugs. Logistic regression analysis revealed that the following were independent factors of the first TTA time: Initial dose, BMI, liver function, heart failure and levofloxacin. Therefore, the results of the present study demonstrated that various factors may affect the first TTA time of warfarin therapy, including the initial dose, BMI, liver function, heart function and concomitant medication.

Risk stratification, perioperative and periprocedural management of the patient receiving anticoagulant therapy

As a result of the aging US population and the subsequent increase in the prevalence of coronary disease and atrial fibrillation, therapeutic use of anticoagulants has increased. Perioperative and periprocedural management of anticoagulated patients has become routine for anesthesiologists, who frequently mediate communication between the prescribing physician and the surgeon and assess the risks of both thromboembolic complications and hemorrhage. Data from randomized clinical trials on perioperative management of antithrombotic therapy are lacking. Therefore, clinical judgment is typically needed regarding decisions to continue, discontinue, bridge, or resume anticoagulation and regarding the time points when these events should occur in the perioperative period. In this review, we will discuss the most commonly used anticoagulants used in outpatient settings and discuss their management in the perioperative period. Special considerations for regional anesthesia and interventional pain procedures will also be reviewed.

Effect of Left Ventricular Systolic Dysfunction on Response to Warfarin

Candidates for chronic warfarin therapy often have co-morbid conditions, such as heart failure, with reduced left ventricular ejection fraction. Previous reports have demonstrated an increased risk of over-anticoagulation due to reduced warfarin dose requirement in patients with decompensated heart failure. However, the influence of left ventricular systolic dysfunction (LVSD), defined as left ventricular ejection fraction <40%, on warfarin response has not been evaluated. Here, we assess the influence of LVSD on warfarin dose, anticoagulation control (percent time in target range), and risk of over-anticoagulation (international normalized ratio >4) and major hemorrhage. Of the 1,354 patients included in this prospective cohort study, 214 patients (16%) had LVSD. Patients with LVSD required 11% lower warfarin dose compared with those without LVSD (p <0.001) using multivariate linear regression analyses. Using multivariate Cox proportional hazards model, patients with LVSD experienced similar levels of anticoagulation control (percent time in target range: 51% vs 53% p = 0.15), risk of over-anticoagulation (international normalized ratio >4; hazard ratio 1.01, 95% confidence interval 0.82 to 1.25; p = 0.91), and risk of major hemorrhage (hazard ratio 1.11; 95% confidence interval 0.70 to 1.74; p = 0.66). Addition of LVSD variable in the model increased the variability explained from 35% to 36% for warfarin dose prediction. In conclusion, our results demonstrate that patients with LVSD require lower doses of warfarin. Whether warfarin dosing algorithms incorporating LVSD in determining initial doses improves outcomes needs to be evaluated.

Effect of diseases on response to vitamin K antagonists

INTRODUCTION

The purpose of this review article is to summarize the literature on diseases that are documented to have an effect on response to warfarin and other VKAs.

METHODS

We searched the English literature from 1946 to September 2015 via PubMed, EMBASE, and Scopus for the effect of diseases on response vitamin K antagonists including warfarin, acenocoumarol, phenprocoumon, and fluindione.

DISCUSSION

Among many factors modifying response to VKAs, several disease states are clinically relevant. Liver disease, hyperthyroidism, and CKD are well documented to increase response to VKAs. Decompensated heart failure, fever, and diarrhea may also elevate response to VKAs, but more study is needed. Hypothyroidism is associated with decreased effect of VKAs, and obese patients will likely require higher initial doses of VKAs.

CONCLUSION

In order to minimize risks with VKAs while ensuring efficacy, clinicians must be aware of the effect of disease states when prescribing these oral anticoagulants.

Changes in Warfarin Sensitivity During Decompensated Heart Failure and Chronic Obstructive Pulmonary Disease

Background: Heart failure (HF) has been associated with an elevated international normalized ratio (INR) in patients on warfarin. Objectives: Compare warfarin sensitivity during hospital admission for HF exacerbation and chronic obstructive pulmonary disease (COPD) exacerbation with admissions unrelated to HF or COPD (controls) as well as during disease stability. Methods: We conducted a case-controlled observational study. Patients admitted to a tertiary teaching hospital for HF exacerbation (n = 37), COPD exacerbation (n = 26), and admissions unrelated to HF or COPD (controls, n = 60) were included. Warfarin sensitivity (INR per daily mg dose of warfarin) at admission was compared to periods of disease stability and also compared between the 3 groups. Results: The increase in warfarin sensitivity at admission was 94% for HF patients ( P < 0.0001), 59% for COPD ( P = 0.003) patients, and 24% for controls ( P = 0.002). HF patients with New York Heart Association (NYHA) class 3 and 4 and NYHA class 1 and 2 experienced changes in warfarin sensitivity of 125% ( P = 0.006) and 50% ( P = 0.13) at admission. HF patients had higher warfarin sensitivity at admission (mean = 1.62 [SD = 1.27]) compared to the control group (0.91 [0.52], P < 0.0001) and COPD group (1.03 [0.79], P = 0.04). and required greater intervention with vitamin K than controls (14% vs 0%, P = 0.007). Conclusion: HF and COPD patients were more sensitive to warfarin during disease exacerbation, with HF exacerbation having the largest impact, resulting in clinically significant management implications.

Coagulopathy and Anticoagulation During Thoracic Surgery

Coagulopathy and bleeding in thoracic surgery may be compounded by the chronic use of anticoagulants and antiplatelet agents. Timely preoperative cessation and postoperative resumption of these antithrombotic drugs are critical in reducing the risks of perioperative major bleeding and thromboembolism. This article describes the various strategies for the optimal perioperative management of antithrombotics based on individual assessment of each patient and the most recent multisociety guidelines.

New strategies for effective treatment of vitamin K antagonist-associated bleeding

Vitamin K antagonists have been used as oral anticoagulants in the treatment and prevention of thromboembolic events for over half a century. Although vitamin K antagonists are effective in the management of thromboembolic events, the need for routine monitoring and the associated risk of bleeding has resulted in the development and licensing of direct oral anticoagulants for specific clinical indications. Despite these developments, vitamin K antagonists remain the oral anticoagulants of choice in many clinical conditions. Severe bleeding associated with oral anticoagulation requires urgent reversal. Several options for the reversal of vitamin K antagonist exist, including vitamin K, prothrombin complex concentrates and plasma. In this manuscript, we review current evidence and provide physicians with treatment strategies for more effective management of vitamin K antagonist-associated bleeding.

Predicting outcomes among patients with atrial fibrillation and heart failure receiving anticoagulation with warfarin

Among patients receiving oral anticoagulation for atrial fibrillation (AF), heart failure (HF) is associated with poor anticoagulation control. However, it is not known which patients with heart failure are at greatest risk of adverse outcomes. We evaluated 62,156 Veterans Health Administration (VA) patients receiving warfarin for AF between 10/1/06-9/30/08 using merged VA-Medicare dataset. We predicted time in therapeutic range (TTR) and rates of adverse events by categorising patients into those with 0, 1, 2, or 3+ of five putative markers of HF severity such as aspartate aminotransferase (AST)> 80 U/l, alkaline phosphatase> 150 U/l, serum sodium< 130 mEq/l, any receipt of metolazone, and any inpatient admission for HF exacerbation. These risk categories predicted TTR: patients without HF (referent) had a mean TTR of 65.0 %, while HF patients with 0, 1, 2, 3 or more markers had mean TTRs of 62.2 %, 57.2 %, 53.5 %, and 50.7 %, respectively (p< 0.001). These categories also discriminated for major haemorrhage well; compared to patients without HF, HF patients with increasing severity had hazard ratios of 1.84, 3.06, 3.52 and 5.14 respectively (p< 0.001). However, although patients with HF had an elevated hazard for bleeding compared to those without HF, these categories did not effectively discriminate risk of ischaemic stroke across HF. In conclusion, we developed a HF severity model using easily available clinical characteristics that performed well to risk-stratify patients with HF who are receiving anticoagulation for AF with regard to major haemorrhage.

Reinitiating warfarin: relationships between dose and selected patient, clinical and hospital measures

BACKGROUND

Warfarin is an oral anticoagulant used in the long-term treatment/prevention of venothromboembolic disease. Patients undergoing elective surgical and non-surgical procedures may require temporary warfarin discontinuation followed by reinitiation after their procedure. Because little information is available regarding best methods for warfarin reinitiation, we investigated current practices to inform management decisions.

METHODS

Subjects were required to have a known and stable warfarin dose prior to discontinuation, which was operationalized by requiring, within 7-days prior to discontinuation, that they have at least one INR in therapeutic range (2.0-3.5), no INR(s) out of range, and no more than a 15% change in warfarin dose. Stable dose prior to discontinuation was defined as the average daily dose received in the 7 days immediately prior to discontinuation. Reinitiation dose was defined as the average daily dose received in the first 3 days after warfarin was restarted. Subjects were divided into three groups based on whether they received approximately the same, a higher, or a lower dose at reinitiation and were also grouped by calendar time into three distinct periods that reflected differing levels of availability of electronic and patient care data that may impact reinitiation dose decisions. These groupings facilitated analyses and descriptions of trends in reinitiation dosing and supported other analyses, including tests for association between dose group and selected subject demographic, clinical, medication and hospitalization measures. All study data were abstracted from Marshfield Clinic electronic patient care and administrative databases and electronic patient care databases from Ministry St. Joseph's Hospital (Marshfield, WI).

RESULTS

We identified 205 subjects with warfarin temporarily discontinued between 1994 and 2012: 99 subjects in same dose group, 32 subjects in the low group, and 74 subjects in the high group. Because relatively wide differences were observed in the proportion of same dose subjects during more recent years (2007-2012) compared to earlier years (54% vs 35%), we focused our analyses on this recent period, which included 140 subjects. Review of physician notes and other documents yielded virtually no information about reasons for reinitiation dose decisions. In addition, tests for association between reinitiation dose group and subject demographic, clinical, medication and hospital measures were uniformly uninformative.

CONCLUSIONS

We observed varied dosing strategies for reinitiating patients on warfarin and, in more recent years, an apparent trend toward reinitiating patients on the same dose. However we could not associate dosing strategy with specific patient demographic, clinical, medication or hospital factors. Many factors influence whether a physician reinitiates a patient at a different dose than his/her prior stable warfarin dose. However, in the absence of clinical indications for modification, we believe patients with a previously established effective dose should be reinitiated at that same dose following temporary warfarin discontinuation.

Factors influencing warfarin response in hospitalized patients

The objective of this study was to investigate the influence of simultaneous factors that potentially keep patients far from achieving target INR range at discharge in hospitalized patients. Prospective cross-sectional observational study conducted at the Cardiology Department and Intensive Care Unit (ICU) of the Assiut University Hospitals. One-hundred and twenty patients were enrolled in the study from July 2013 to January 2014. Outcome measures were discharge INRs, bleeding and thromboembolic episodes. Bivariate analysis and multinomial logistic regression were conducted to determine independent risk factors that can keep patients outside target INR range.

Patients who were newly initiated warfarin on hospital admission were given low initiation dose (2.8 mg ± 0.9). They were more likely to have INR values below 1.5 during hospital stay, 13 (27.7%) patients compared with 9 (12.3%) previously treated patients, respectively (p = .034). We found that the best predictors of achieving below target INR range relative to within target INR range were; shorter hospital stay periods (OR, 0.82 for every day increase [95% CI, 0.72–0.94]), being a male patient (OR, 2.86 [95% CI, 1.05–7.69]), concurrent infection (OR, 0.21 [95% CI, 0.07–0.59]) and new initiation of warfarin therapy on hospital admission (OR, 3.73 [95% CI, 1.28–10.9]).

Gender, new initiation of warfarin therapy on hospital admission, shorter hospital stay periods and concurrent infection can have a significant effect on discharge INRs. Initiation of warfarin without giving loading doses increases the risk of having INRs below 1.5 during hospital stay and increases the likelihood of a patient to be discharged with INR below target range. Following warfarin dosing nomograms and careful monitoring of the effect of various factors on warfarin response should be greatly considered.

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.

Impact of CYP2C9 polymorphisms on the vulnerability to pharmacokinetic drug-drug interactions during acenocoumarol treatment

AIM

The objective of this study was to investigate the impact of CYP2C9 polymorphisms and drug-drug interactions on the risk of overanticoagulation in patients treated with acenocoumarol, a vitamin K antagonist.

MATERIALS & METHODS

A prospective observational study was performed on patients starting acenocoumarol (n = 115). CYP2C9 genotypes were assessed. Data on International Normalized Ratio, comedications and doses of acenocoumarol were collected during the first 35 days of therapy. Overanticoagulation was defined as the occurrence of at least one International Normalized Ratio ≥4.

RESULTS

The presence of a CYP2C9 inhibitor or a CYP2C9 polymorphisms statistically increased the risk of overanticoagulation (hazard ratio [HR]: 2.8, p < 0.001 and HR: 1.7, p = 0.04, respectively). The presence of CYP2C9 polymorphisms almost tripled the risk of overanticoagulation (HR: 2.91, p = 0.01) in the presence of a clinically significant drug-drug interaction.

CONCLUSION

These findings support the fact that CYP2C9 genotyping could be useful to identify patients requiring closer monitoring, especially when a drug-drug interaction is expected.

Antithrombotic therapy in atrial fibrillation: ximelagatran, an oral direct thrombin inhibitor

The oral direct thrombin inhibitor ximelagatran (Exanta, AstraZeneca) is rapidly absorbed, is efficiently bioconverted to the active form, melagatran (AstraZeneca) and has shown efficacy and relative safety as an anticoagulant for prophylaxis and therapy of thromboembolism. Two Phase III trials, Stroke Prevention using an ORal Thrombin Inhibitor in atrial Fibrillation (SPORTIF V), have tested the hypothesis that oral ximelagatran, administered 36 mg twice daily without coagulation monitoring or dose adjustment, prevents stroke and systemic embolism at least as effectively as adjusted-dose warfarin (international normalized ratio, 2.0-3.0) in patients with nonvalvular atrial fibrillation. Both were randomized, multicenter trials (n > 3000 per trial) with blinded end-point assessment. The open-label SPORTIF III trial confirmed the noninferiority of ximelagatran versus warfarin. Publication of the full results from SPORTIF V is pending.

Does chronic warfarin cause increased blood loss and transfusion during lumbar spinal surgery?

BACKGROUND CONTEXT

The use of oral anticoagulation therapy such as warfarin is projected to increase significantly as the population ages and the prevalence of cardiovascular disease increases. Current recommendations state that warfarin be discontinued before surgery and the international normalized ratio (INR) normalized.

PURPOSE

To determine if stopping warfarin 7 days before surgery and correcting INR had any effect on intraoperative blood loss or the requirements for blood product transfusion.

STUDY DESIGN/SETTING

This was a retrospective cohort study in a high-volume tertiary care center.

PATIENT SAMPLE

Sample comprised 263 consecutive patients who underwent elective lumbar spinal surgery.

OUTCOME MEASURE

The outcome measures were intraoperative blood loss, intraoperative blood transfusion, postoperative blood transfusion, and the number of blood products transfused.

METHODS

The records of patients undergoing elective spinal surgery were analyzed for patient demographic data, comorbidities, coagulation panel laboratory findings, operative characteristics, blood loss, and blood transfusion requirements. These included patients undergoing full laminectomies with or without posterolateral fusion and instrumentation. Patients on warfarin were analyzed for the mean dosage of warfarin and underlying pathology that required anticoagulation. All patients on warfarin had their anticoagulation therapy stopped 7 days before surgery and their INR checked preoperatively to confirm normalization. Both univariate and multiple linear regression analyses were performed.

RESULTS

The patients on warfarin had a mean intraoperative blood loss of 839 mL compared with 441 mL for patients not on warfarin (p<.01). Multiple regression analysis determined that warfarin and number of spinal levels decompressed/fused/instrumented were predictors for increased blood loss (R(2)=0.37). Patients on warfarin also had increased postoperative blood transfusions (23.1% compared with 7.4%, p=.04). There was no significant difference between groups in terms of intraoperative blood transfusion or number of units transfused.

CONCLUSIONS

Patients on chronic anticoagulation therapy with warfarin who have their therapy stopped 7 days before surgery and have their INR normalized still demonstrated increased intraoperative blood loss and requirement for postoperative transfusion. Surgeons should be aware of the increased propensity of these patients to bleed despite adherence to protocols and should attempt to mitigate this risk.

Vitamin K antagonists and time in the therapeutic range: implications, challenges, and strategies for improvement

Oral vitamin K antagonists are highly efficacious in the prevention and treatment of thromboembolic disease. Optimal use of these agents in clinical practice is challenged by their narrow therapeutic window. The proportion of time spent in the International Normalized Ratio (INR) range of 2.0-3.0 [time in the therapeutic range (TTR)] has been closely associated with adverse outcomes, i.e., stroke, hemorrhage, mortality. Although TTR is a validated marker, it has several limitations. TTR does not capture short-term risks associated with highly variable periods or periods characterized by extreme deviations in INR. Because TTR measurement is limited to consecutive periods of warfarin exposure, it does not inform the risks associated with gap periods of 56 days or greater as these time intervals are excluded from end-point rate calculations. Because individuals with gaps in monitoring represent a different patient population than those without gaps, e.g., less adherent, more acutely ill, more frequent transitions in health status, TTR analyses are likely most valid and informative for individuals with uninterrupted monitoring of the INR. Duration of warfarin therapy and patient-specific factors have also been shown to influence TTR. Younger age, female sex, lower income, black race, frequent hospitalizations, polypharmacy, active cancer, decompensated heart failure, substance abuse, psychiatric disorders, dementia, and chronic liver disease have all been associated with lower TTR. Targeted strategies to improve TTR are urgently needed.

Oral Anticoagulation Therapy for Elderly Patients With Atrial Fibrillation

Elderly individuals are prone to nonvalvular atrial fibrillation (AF) with associated risks of arterial thromboembolic disease. Despite definitive guidelines, oral anticoagulant therapy (OAC) is notoriously underutilized in patients with AF. Physicians cite excessive bleeding risk as one reason they omit OAC for their older patients with AF. Improved understanding of the pathophysiology of age-related bleeding may improve risk–benefit assessments for warfarin and newer antithrombotic agents. We reviewed the literature to identify age-related pathophysiological elements that can exacerbate the likelihood of bleeding. In the context of the Hypertension, Abnormal renal/liver function, Stroke, Bleeding history or predisposition, Labile international normalized ratio, Elderly, Drugs/alcohol concomitantly (HAS-BLED) bleeding risk framework, we highlight age-related physiological dynamics that predispose to hemorrhage. The combination of increased age (>65 years) with the other elements of the risk factor stratification model identifies patients with AF who are especially susceptible to OAC-related bleeding, irrespective of the agent used. Empirically adjusting OAC dose relative to these common bleeding risks may help to achieve an improved risk–benefit therapeutic ratio.