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Dryden L, Song J, Valenzano TJ, Yang Z, Debnath M, Lin R, Topolovec-Vranic J, Mamdani M, Antoniou T. Evaluation of Machine Learning Approaches for Predicting Warfarin Discharge Dose in Cardiac Surgery Patients: Retrospective Algorithm Development and Validation Study. JMIR Cardio 2023; 7:e47262. [PMID: 38055310 PMCID: PMC10733832 DOI: 10.2196/47262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 09/28/2023] [Accepted: 10/04/2023] [Indexed: 12/07/2023] Open
Abstract
BACKGROUND Warfarin dosing in cardiac surgery patients is complicated by a heightened sensitivity to the drug, predisposing patients to adverse events. Predictive algorithms are therefore needed to guide warfarin dosing in cardiac surgery patients. OBJECTIVE This study aimed to develop and validate an algorithm for predicting the warfarin dose needed to attain a therapeutic international normalized ratio (INR) at the time of discharge in cardiac surgery patients. METHODS We abstracted variables influencing warfarin dosage from the records of 1031 encounters initiating warfarin between April 1, 2011, and November 29, 2019, at St Michael's Hospital in Toronto, Ontario, Canada. We compared the performance of penalized linear regression, k-nearest neighbors, random forest regression, gradient boosting, multivariate adaptive regression splines, and an ensemble model combining the predictions of the 5 regression models. We developed and validated separate models for predicting the warfarin dose required for achieving a discharge INR of 2.0-3.0 in patients undergoing all forms of cardiac surgery except mechanical mitral valve replacement and a discharge INR of 2.5-3.5 in patients receiving a mechanical mitral valve replacement. For the former, we selected 80% of encounters (n=780) who had initiated warfarin during their hospital admission and had achieved a target INR of 2.0-3.0 at the time of discharge as the training cohort. Following 10-fold cross-validation, model accuracy was evaluated in a test cohort comprised solely of cardiac surgery patients. For patients requiring a target INR of 2.5-3.5 (n=165), we used leave-p-out cross-validation (p=3 observations) to estimate model performance. For each approach, we determined the mean absolute error (MAE) and the proportion of predictions within 20% of the true warfarin dose. We retrospectively evaluated the best-performing algorithm in clinical practice by comparing the proportion of cardiovascular surgery patients discharged with a therapeutic INR before (April 2011 and July 2019) and following (September 2021 and May 2, 2022) its implementation in routine care. RESULTS Random forest regression was the best-performing model for patients with a target INR of 2.0-3.0, an MAE of 1.13 mg, and 39.5% of predictions of falling within 20% of the actual therapeutic discharge dose. For patients with a target INR of 2.5-3.5, the ensemble model performed best, with an MAE of 1.11 mg and 43.6% of predictions being within 20% of the actual therapeutic discharge dose. The proportion of cardiovascular surgery patients discharged with a therapeutic INR before and following implementation of these algorithms in clinical practice was 47.5% (305/641) and 61.1% (11/18), respectively. CONCLUSIONS Machine learning algorithms based on routinely available clinical data can help guide initial warfarin dosing in cardiac surgery patients and optimize the postsurgical anticoagulation of these patients.
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Affiliation(s)
| | | | | | - Zhen Yang
- Unity Health Toronto, Toronto, ON, Canada
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Influence of Vitamin D Status on the Maintenance Dose of Warfarin in Patients Receiving Chronic Warfarin Therapy. Cardiol Ther 2022; 11:421-432. [PMID: 35718837 PMCID: PMC9381664 DOI: 10.1007/s40119-022-00268-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 05/30/2022] [Indexed: 11/02/2022] Open
Abstract
INTRODUCTION Considering the anticoagulant actions of vitamin D, we hypothesize that vitamin D status might affect the required dose of warfarin for maintaining the therapeutic international normalized ratio (INR). METHODS In a retrospective single-center cohort study, serum levels of 25-hydroxyvitamin D were assessed for 89 subjects receiving a stable dose of warfarin for 3 months or longer and had a stable INR between 2 and 3.5 for at least three consecutive visits. A warfarin sensitivity index (WSI), defined as the steady-state INR divided by the mean daily warfarin dose, was used for measuring the warfarin dose response. The relation between the serum level of 25-hydroxyvitamin D and WSI value and the difference in the mean WSI value between the subjects with different vitamin D status categories (sufficient, insufficient, and deficient) were assessed. RESULTS Twenty-one subjects had vitamin D deficiency, 43 had vitamin D insufficiency, and only 25 had normal levels of 25-hydroxyvitamin D. Based on the multiple linear regression analysis, there was a significant but weakly positive correlation between WSI and 25-hydroxyvitamin D serum levels, as the value of WSI increases by almost 0.0027434 for every unit increase in 25-hydroxyvitamin D serum level (p value = 0.041). Using one-way ANOVA analysis, there was a trend in a significant difference between the groups with different vitamin D status categories regarding the mean WSI value (F = 2.95, p value = 0.057), as subjects with sufficient vitamin D state compared to those with vitamin D deficiency had a higher WSI value. CONCLUSIONS Although the study's limitations limit our ability to draw definite conclusions, the present data suggest that in addition to other traditional factors, vitamin D status might also affect warfarin sensitivity and maintenance dose requirement. However, to more clearly explain this link, further studies with high involvement subjects are required.
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Sabry S, El Wakeel LM, Saleh A, Ahmed MA. Comparison of Warfarin Initiation at 3 mg Versus 5 mg for Anticoagulation of Patients with Mechanical Mitral Valve Replacement Surgery: A Prospective Randomized Trial. Clin Drug Investig 2022; 42:309-318. [PMID: 35274222 PMCID: PMC8989817 DOI: 10.1007/s40261-022-01137-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/22/2022] [Indexed: 12/01/2022]
Abstract
Background The increased warfarin sensitivity observed after mechanical mitral valve replacement (MVR) operations dictates clinical discretion in warfarin dose initiation. Evidence is still lacking with regard to anticoagulation management of MVR patients. Objective This study aimed to compare initiating warfarin at the recommended dosing regimen versus empirically lowered doses intended to account for the variation in warfarin sensitivity. Methods A prospective, single-blind, randomized, comparative study was conducted in postoperative MVR patients. Patients were randomly assigned to either the 5 mg group (n = 25) or the 3 mg group (n = 25) and were initiated on a 5 or 3 mg warfarin dose, respectively. Time to target international normalized ratio (INR), time in therapeutic range, occurrence of bleeding/thromboembolic events, and cost of bridging with enoxaparin were assessed for both groups. Results Target INR was achieved earlier in the 5 mg group than in the 3 mg group (p = 0.033), with a mean ± SD of 5.3 ± 2.0 and 6.6 ± 2.0, respectively (95% confidence interval of the mean difference 1.022–1.890). Bleeding events did not differ significantly between the two groups. The cost of enoxaparin consumption per patient was significantly higher in the 3 mg group versus the 5 mg group (p = 0.002). Conclusions The initiation of warfarin at a 5 mg dose in MVR patients was more efficacious than the 3 mg dose in terms of time to reach the target INR. Moreover, the cost of enoxaparin bridging was significantly reduced with a 5 mg warfarin initiation dose. Bleeding events were comparable. ClinicalTrials.gov ID NCT04235569, 22 January 2020.
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Affiliation(s)
- Sarah Sabry
- The Cardiovascular Hospital, Ain Shams University, Cairo, Egypt
| | - Lamia Mohamed El Wakeel
- Department of Clinical Pharmacy, Faculty of Pharmacy, Ain Shams University, 8/4 Badr Street from Al Gazaer Street, New Maadi, Cairo, Egypt
| | - Ayman Saleh
- Department of Cardiology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Marwa Adel Ahmed
- Department of Clinical Pharmacy, Faculty of Pharmacy, Ain Shams University, 8/4 Badr Street from Al Gazaer Street, New Maadi, Cairo, Egypt.
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4
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Godoy LC, Tomlinson G, Abumuamar AM, Farkouh ME, Rudolph M, Billia F, Cohn I, Marcus G, Kim RH, Rao V, Lawler PR. Association between time to therapeutic INR and length of stay following mechanical heart valve surgery. J Card Surg 2021; 37:62-69. [PMID: 34662458 DOI: 10.1111/jocs.16083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 10/08/2021] [Accepted: 10/09/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND Warfarin is the only oral anticoagulant approved for use following mechanical valve surgery (MeVS). Patients may experience prolonged hospital length of stay (LOS) following MeVS awaiting an appropriate warfarin effect. We aimed to determine whether an association exists between time to achieve the first therapeutic international normalized ratio (INR) and LOS following MeVS. MATERIALS AND METHODS Retrospective single center cohort study. We included consecutive adult patients undergoing elective MeVS from 2013 to 2018. Landmark analyses and multivariable regression with time-updated INR were used to estimate the association between time to therapeutic INR (TTI) and LOS. RESULTS Among 384 patients (median age: 51 years, interquartile range [IQR]: 41-57; 58.3% male), the median TTI was 4 days (IQR: 2-5). Thirty seven percent of patients were discharged with a subtherapeutic INR, many on bridging anticoagulation or with an INR close to target. Those achieving therapeutic INR had an increased rate of hospital discharge (adjusted hazard ratio: 2.17; 95% confidence interval: 1.71-2.76; p < .0001). Attainment of a therapeutic INR anytime between postoperative Days 4 and 13 was significantly associated with a shorter LOS. CONCLUSIONS Prolonged time to achieve a therapeutic INR was independently associated with prolonged LOS. Future strategies aimed at improving attainment of therapeutic INR following MeVS may reduce hospital LOS.
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Affiliation(s)
- Lucas C Godoy
- Division of Cardiology, Peter Munk Cardiac Centre, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada.,Instituto do Coracao (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, São Paulo, Sao Paulo, Brazil
| | - George Tomlinson
- Biostatistics Research Unit, Toronto General Hospital Research Institute, University of Toronto, Toronto, Ontario, Canada
| | - Asmaa M Abumuamar
- Division of Cardiology, Peter Munk Cardiac Centre, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Michael E Farkouh
- Division of Cardiology, Peter Munk Cardiac Centre, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Madeleine Rudolph
- Division of Cardiology, Peter Munk Cardiac Centre, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Filio Billia
- Division of Cardiology, Peter Munk Cardiac Centre, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Iris Cohn
- Division of Clinical Pharmacology and Toxicology, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Gil Marcus
- Division of Cardiology, Peter Munk Cardiac Centre, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada.,Department of Cardiology, Shamir Medical Center, Zeriffin, Israel.,Schulich Heart Program, Division of Cardiology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Raymond H Kim
- Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Ted Rogers Centre for Heart Research, University of Toronto, Toronto, Ontario, Canada.,Division of Medical Oncology and Hematology, University Health Network, Sinai Health System, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Vivek Rao
- Division of Cardiovascular Surgery, Peter Munk Cardiac Centre, University of Toronto, Toronto, Ontario, Canada
| | - Patrick R Lawler
- Division of Cardiology, Peter Munk Cardiac Centre, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada.,Division of Cardiology and Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada
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5
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Li D, Zhu H, Luo ZY, Chen Y, Song GB, Zhou XM, Yan H, Zhou HH, Zhang W, Li X. LRP1 polymorphisms associated with warfarin stable dose in Chinese patients: a stepwise conditional analysis. Pharmacogenomics 2020; 21:1169-1178. [PMID: 33094665 DOI: 10.2217/pgs-2020-0004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aim: The aim of this study was to investigate whether variability in warfarin stable dose (WSD) could be influenced by vitamin K-related polymorphisms in patients with heart valve replacement. Patients & methods: Twenty-nine vitamin K-related SNPs in 208 patients who initially took warfarin and achieved WSD were genotyped. Results: After conducting conditional analysis for both VKORC1 -1639G>A and CYP2C9*3, LRP1 rs1800139 and LRP1 rs1800154 were significantly associated with WSD (p = 0.007 and p = 0.015, respectively). Multivariate analysis showed that LRP1 rs1800139 accounted for 5.9% WSD variability. Conclusion: Our results suggest that a novel vitamin K-related gene, LRP1, exerts a relevant influence on WSD, independent of VKORC1 -1639G>A and CYP2C9*3.
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Affiliation(s)
- Dan Li
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, Hunan, 410008, PR China.,Department of Neurosurgery, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, Hunan, 410008, PR China.,Institute of Clinical Pharmacology, Central South University; Hunan Key Laboratory of Pharmacogenetics, Changsha, 410078, PR China
| | - Hong Zhu
- Department of Cardiovascular Surgery, Xiangya Hospital, Central South University, Changsha, 410008, PR China
| | - Zhi-Ying Luo
- Department of Pharmacy, The Second Xiangya Hospital, Central South University, Changsha, 410011, PR China
| | - Yi Chen
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, Hunan, 410008, PR China.,Department of Neurosurgery, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, Hunan, 410008, PR China.,Institute of Clinical Pharmacology, Central South University; Hunan Key Laboratory of Pharmacogenetics, Changsha, 410078, PR China
| | - Guo-Bao Song
- Department of Cardio-Thoracic Surgery, the Second Xiangya Hospital, Central South University, Changsha, 410011, PR China
| | - Xin-Ming Zhou
- Department of Cardio-Thoracic Surgery, the Second Xiangya Hospital, Central South University, Changsha, 410011, PR China
| | - Han Yan
- Department of Pharmacy, The Second Xiangya Hospital, Central South University, Changsha, 410011, PR China
| | - Hong-Hao Zhou
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, Hunan, 410008, PR China.,Department of Neurosurgery, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, Hunan, 410008, PR China.,Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, PR China.,Institute of Clinical Pharmacology, Central South University; Hunan Key Laboratory of Pharmacogenetics, Changsha, 410078, PR China
| | - Wei Zhang
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, Hunan, 410008, PR China.,Department of Neurosurgery, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, Hunan, 410008, PR China.,Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, PR China.,Institute of Clinical Pharmacology, Central South University; Hunan Key Laboratory of Pharmacogenetics, Changsha, 410078, PR China
| | - Xi Li
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, Hunan, 410008, PR China.,Department of Neurosurgery, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, Hunan, 410008, PR China.,Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, PR China.,Institute of Clinical Pharmacology, Central South University; Hunan Key Laboratory of Pharmacogenetics, Changsha, 410078, PR China
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6
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Miano TA, Yang W, Shashaty MGS, Zuppa A, Brown JR, Hennessy S. The Magnitude of the Warfarin-Amiodarone Drug-Drug Interaction Varies With Renal Function: A Propensity-Matched Cohort Study. Clin Pharmacol Ther 2020; 107:1446-1456. [PMID: 32112562 DOI: 10.1002/cpt.1819] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 02/16/2020] [Indexed: 12/20/2022]
Abstract
Amiodarone inhibits warfarin metabolism and is associated with major bleeding during warfarin therapy. Managing this drug-drug interaction (DDI) is challenging because of substantial interpatient variability in DDI magnitude. Because renal dysfunction induces changes in drug metabolism and protein binding that could alter cytochrome P450 inhibition mechanisms, we hypothesized that renal dysfunction alters the impact of the warfarin-amiodarone DDI. We tested this question in a propensity-matched cohort study of hospitalized patients with atrial fibrillation. Patients were queried from an electronic health record database. Renal function was estimated with creatinine clearance (CrCl). Warfarin response was measured with the warfarin sensitivity index (WSI), a dose-normalized international normalized ratio (INR) measure, and was modeled with multilevel mixed-effects linear regression. Time to supratherapeutic INR (> 4) was modeled using Cox regression. Propensity score matching resulted in 4,518 patients administered amiodarone and 4,518 controls. Amiodarone's effect on warfarin response varied threefold across the renal function range, increasing WSI by 36% in patients with normal renal function (CrCl 115 mL/minute), but by only 11.8% in patients with severe renal dysfunction (CrCl 15 mL/minute). Similarly, amiodarone had a strong effect in patients with normal renal function (hazard ratio (HR) 1.80; 1.23, 2.64), but a negligible effect on supratherapeutic INR hazard in patients with severe renal dysfunction (HR 1.01; 0.75, 1.37). These results suggest that renal function is a novel factor that explains substantial variability in the warfarin-amiodarone DDI. This information could inform warfarin dosage adjustment and monitoring and may have implications for the selection of oral anticoagulation agents in patients treated with amiodarone.
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Affiliation(s)
- Todd A Miano
- Center for Pharmacoepidemiology Research and Training, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Wei Yang
- Center for Pharmacoepidemiology Research and Training, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Michael G S Shashaty
- Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Pulmonary, Allergy, and Critical Care Division, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Athena Zuppa
- Department of Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jeremiah R Brown
- The Dartmouth Institute for Health Policy and Clinical Practice, Lebanon, New Hampshire, USA.,Department of Epidemiology, Geisel School of Medicine, Hanover, New Hampshire, USA.,Department of Biomedical Data Science, Geisel School of Medicine, Hanover, New Hampshire, USA
| | - Sean Hennessy
- Center for Pharmacoepidemiology Research and Training, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
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DeCarolis DD, Chen YC, Westanmo AD, Conley C, Gravely AA, Khan FB. Decreased warfarin sensitivity among patients treated with elbasvir and grazoprevir for hepatitis C infection. Am J Health Syst Pharm 2019; 76:1273-1280. [PMID: 31418789 DOI: 10.1093/ajhp/zxz127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
PURPOSE We previously reported an interaction with warfarin anticoagulation when initiating treatment with direct-acting antiviral agents for hepatitis C infection. A decreased warfarin sensitivity led to subtherapeutic anticoagulation. To study this interaction further, we expanded our research to include patients treated with the combination of elbasvir and grazoprevir concurrent with warfarin anticoagulation and investigated changes in warfarin sensitivity during and after treatment. METHODS Using electronic health records of the Veterans Health Administration, patients starting treatment with elbasvir-grazoprevir for hepatitis C infection concurrent with warfarin anticoagulation were identified. Inclusion required stable warfarin anticoagulation prior to 12 weeks of treatment with elbasvir-grazoprevir. A warfarin sensitivity index (WSI) was calculated at the start of treatment, after 12 weeks after treatment, and at the end of treatment. The primary endpoint was the difference in WSI from pre- to end-treatment. The secondary endpoint was the WSI difference from before treatment to Changes in International Normalized Ratio, warfarin doses, and time in therapeutic range were measured. RESULTS In the final sample of 43 patients, the mean WSI decreased during treatment from 0.53 to 0.40, or 25.2%. After treatment, the mean WSI rose to 0.51. Although the mean weekly warfarin dose increased from 40.3 to 44.6 mg during treatment, the mean International Normalized Ratio decreased from 2.40 to 1.96, recovering to 2.59 after treatment. The time spent in therapeutic range decreased from 74.1% before treatment to 39.8% during treatment and back to 64.9% 12 weeks posttreatment. CONCLUSION When elbasvir-grazoprevir was added to stable warfarin anticoagulation, warfarin sensitivity decreased significantly during treatment and returned to baseline after treatment.
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Affiliation(s)
| | - Yi-Chieh Chen
- Pharmacy, Mayo Clinic Health System-Austin, Austin, MN
| | | | | | - Amy A Gravely
- Research Service, Minneapolis VA Health Care System, Minneapolis, MN
| | - Fatima B Khan
- Department of Hematology/Oncology, Minneapolis VA Health Care System, Minneapolis, MN
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Olson LM, Nei AM, Dierkhising RA, Joyce DL, Nei SD. Warfarin-Induced Rapid Rise in INR Post-Cardiac Surgery Is Not Associated With Increased Bleeding Risk. Ann Pharmacother 2019; 53:1184-1191. [PMID: 31304766 DOI: 10.1177/1060028019858677] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Background: Post-cardiac surgery bleeding can have devastating consequences, and it is unknown if warfarin-induced rapid international normalized ratio (INR) rise during the immediate postoperative period increases bleed risk. Objective: To determine the impact of warfarin-induced rapid-rise INR on post-cardiac surgery bleeding. Methods: This was a single-center, retrospective chart review of post-cardiac surgery patients initiated on warfarin at Mayo Clinic Hospital, Rochester. Patients were grouped based on occurrence or absence of rapid-rise INR (increase ≥1.0 within 24 hours). The primary outcome compared bleed events between groups. Secondary outcomes assessed hospital length of stay (LOS) and identified risk factors associated with bleed events and rapid rise in INR. Results: During the study period, 2342 patients were included, and 56 bleed events were evaluated. Bleed events were similar between rapid-rise (n = 752) and non-rapid-rise (n = 1590) groups in both univariate (hazard ratio [HR] = 1.22; P = 0.594) and multivariable models (HR = 1.24; P = 0.561). Those with rapid-rise INR had longer LOS after warfarin administration (discharge HR = 0.84; P = 0.0002). The most common warfarin dose immediately prior to rapid rise was 5 mg. Risk factors for rapid-rise INR were low body mass index, female gender, and cross-clamp time. Conclusion and Relevance: This represents the first report to assess warfarin-related rapid-rise INR in post-cardiac surgery patients and found correlation to hospital LOS but not bleed events. Conservative warfarin dosing may be warranted until further research can be conducted.
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9
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Tyson K, Hutchinson N, Williams S, Scutt G. Identification of clinical factors predicting warfarin sensitivity after cardiac surgery. Ther Adv Drug Saf 2018; 9:415-424. [PMID: 30364757 DOI: 10.1177/2042098618776541] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 04/23/2018] [Indexed: 11/15/2022] Open
Abstract
Background Warfarin is commonly initiated post-cardiac surgery to reduce the risk of intracardiac thrombus formation. Studies have found that sensitivity is increased after cardiac surgery and anticoagulation is subsequently difficult to manage. This study set out to identify clinical markers of increased warfarin sensitivity in patients after cardiac surgery, and build a model that can predict warfarin sensitivity, and improve safety in this setting. Methods The study was an observational, retrospective cohort design. Clinical parameters including left ventricular ejection fraction (LVEF), cross-clamp time, age, serum albumin and C-reactive protein concentrations were collected from consenting patients who had undergone cardiac surgery and were prescribed postoperative warfarin. The warfarin dose index (WDI) was calculated for each patient from their international normalized ratio (INR) and warfarin dose, as a measure of sensitivity. Results A total of 41 patients were recruited to the study. Logarithmically transformed WDI (log WDI) significantly correlated with LVEF, cardiopulmonary bypass (CPB) time, cross-clamp time, baseline INR and co-administration of amiodarone (p < 0.05). When added to a linear regression model, LVEF and cross-clamp time produced a model that accounted for 41% of the variance in log WDI (R2 = 0.41), p = 0.0002). Applying a log WDI cutoff value of -0.349 discriminated between patients who develop an INR > 4 and those who do not, with a sensitivity of 75% and a specificity of 70%. Conclusions This single-centre study has highlighted two risk factors for increased warfarin sensitivity post-cardiac surgery. Further research is needed to confirm these findings in a wider, more diverse population, and to validate this model.
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Affiliation(s)
- Karen Tyson
- Pharmacy Department, Brighton and Sussex University Hospitals NHS Trust, Brighton, UKBrighton and Sussex Centre for Medicines Optimisation, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, UK
| | - Nevil Hutchinson
- Department of Anaesthesia, Brighton and Sussex University Hospitals NHS Trust, Brighton, UK
| | - Sian Williams
- Brighton and Sussex Centre for Medicines Optimisation, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, UK
| | - Greg Scutt
- Brighton and Sussex Centre for Medicines Optimisation. School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, BN2 4GJ, UK
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10
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Olson LM, Nei AM, Joyce DL, Ou NN, Dierkhising RA, Nei SD. Comparison of Warfarin Requirements in Post-cardiac Surgery Patients: Valve Replacement Versus Non-valve Replacement. Am J Cardiovasc Drugs 2018; 18:223-229. [PMID: 29327158 DOI: 10.1007/s40256-017-0261-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Anticoagulation with warfarin affects approximately 140,000 post-cardiac surgery patients every year, yet there remains limited published data in this patient population. Dosing remains highly variable due to intrinsic risk factors that plague cardiac surgery candidates and a lack of diverse literature that can be applied to those who have undergone a cardiac surgery alternative to heart valve replacement (HVR). In the present study, our aim was to compare the warfarin requirements between HVR and non-HVR patients. METHODS This was a single-center, retrospective study of post-cardiac surgery patients initiated on warfarin at Mayo Clinic Hospital, Rochester, from January 1st, 2013 to October 31st, 2016. The primary outcome was the maintenance warfarin dose at the earliest of discharge or warfarin day 10 between patients with HVR and non-HVR cardiac surgeries. RESULTS A total of 683 patients were assessed during the study period: 408 in the HVR group and 275 in the non-HVR group. The mean warfarin maintenance doses in the HVR and non-HVR groups were 2.55 mg [standard deviation (SD) 1.52] and 2.43 mg (SD 1.21), respectively (adjusted p = 0.65). A multivariable analysis was performed to adjust for gender, age, body mass index and drug interactions. CONCLUSIONS This was the largest study to evaluate warfarin dose requirements in post-cardiac surgery patients and is the first to compare warfarin requirements between HVR and non-HVR patients during the immediate post-operative period. Both groups had similar warfarin requirements, which supports expanding the initial warfarin dosing recommendations of the 9th edition Chest guideline to include non-HVR patients as well as HVR patients.
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11
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Time to achieving therapeutic international normalized ratio increases hospital length of stay after heart valve replacement surgery. Am Heart J 2017; 187:70-77. [PMID: 28454810 DOI: 10.1016/j.ahj.2017.02.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 02/08/2017] [Indexed: 11/22/2022]
Abstract
BACKGROUND Achieving a therapeutic international normalized ratio (INR) before hospital discharge is an important inpatient goal for patients undergoing mechanical cardiac valve replacement (MCVR). The use of clinical algorithms has reduced the time to achieve therapeutic INR (TTI) with warfarin therapy. Whether TTI prolongs length of stay (LOS) is unknown. METHODS Patients who underwent MCVR over a consecutive 42-month period were included. Clinical data were obtained from the Society of Thoracic Surgeons Adult Cardiac Surgery database and electronic medical records. Therapeutic INR was defined as per standard guidelines. Warfarin dose was prescribed using an inpatient pharmacy-managed algorithm and computer-based dosing tool. International normalized ratio trajectory, procedural needs, and drug interactions were included in warfarin dose determination. RESULTS There were 708 patients who underwent MCVR, of which 159 were excluded for reasons that would preclude or interrupt warfarin use. Among the remainder of 549 patients, the average LOS was 6.4days and mean TTI was 3.5days. Landmark analysis showed that subjects in hospital on day 4 (n=542) who achieved therapeutic INR were more likely to be discharged by day 6 compared with those who did not achieve therapeutic INR (75% vs 59%, P<.001). Multivariable proportional hazards regression with TTI as a time-dependent effect showed a strong association with discharge (P=.0096, hazard ratio1.3) after adjustment for other significant clinical covariates. CONCLUSIONS Time to achieve therapeutic INR is an independent predictor of LOS in patients requiring anticoagulation with warfarin after MCVR surgery. Alternative dosing and anticoagulation strategies will need to be adopted to reduce LOS in these patients.
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Roberts G, Razooqi R, Quinn S. Comparing Usual Care With a Warfarin Initiation Protocol After Mechanical Heart Valve Replacement. Ann Pharmacother 2016; 51:219-225. [PMID: 27798318 DOI: 10.1177/1060028016676830] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND The immediate postoperative warfarin sensitivity for patients receiving heart valve prostheses is increased. Established warfarin initiation protocols may lack clinical applicability, resulting in dosing based on clinical judgment. OBJECTIVE To compare current practice for warfarin initiation with a known warfarin initiation protocol, with doses proportionally reduced to account for the increased postoperative sensitivity. METHODS We compared the Mechanical Heart Valve Warfarin Initiation Protocol (Protocol group) with current practice (clinical judgment-Empirical group) for patients receiving mechanical heart valves in an observational before-and-after format. End points were the time to achieve a stable therapeutic international normalized ratio (INR), doses held in the first 6 days, and overanticoagulation in the first 6 days. RESULTS The Protocol group (n = 37) achieved a stable INR more rapidly than the Empirical group (n = 77; median times 5.1 and 8.7 days, respectively; P = 0.002). Multivariable analysis indicated that the Protocol group (hazard ratio [HR] = 2.22; P = 0.005) and men (HR = 1.76; P = 0.043) more rapidly achieved a stable therapeutic INR. Age, serum albumin, amiodarone, presence of severe heart failure, and surgery type had no impact. Protocol patients had fewer doses held (1.1% vs 10.1%, P < 0.001) and no difference in overanticoagulation (2.7% vs 9.1%, P = 0.27). CONCLUSION The Mechanical Heart Valve Warfarin Initiation Protocol provided a reliable approach to initiating warfarin in patients receiving mechanical aortic or mitral valves.
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Affiliation(s)
- Gregory Roberts
- 1 Flinders Medical Centre, Bedford Park, South Australia, Australia.,2 Flinders University, Bedford Park, South Australia, Australia
| | - Rasha Razooqi
- 3 University of South Australia, Adelaide, South Australia, Australia
| | - Stephen Quinn
- 2 Flinders University, Bedford Park, South Australia, Australia
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DeCarolis DD, Westanmo AD, Chen YC, Boese AL, Walquist MA, Rector TS. Evaluation of a Potential Interaction Between New Regimens to Treat Hepatitis C and Warfarin. Ann Pharmacother 2016; 50:909-917. [PMID: 27465881 DOI: 10.1177/1060028016660325] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE New regimens to treat hepatitis C virus infection have expanded the eligible patient population to include more patients receiving concurrent warfarin. The primary objective of this study was to assess whether a drug interaction occurs when these regimens are added to warfarin therapy. METHODS This was a retrospective cohort design using a nationwide database of the Veterans Affairs Health System. Patients on warfarin therapy treated with sofosbuvir or ombitasvir, paritaprevir-ritonavir, and dasabuvir (OBV-PTV/r-DSV) from March 2014 through October 2015 were identified. The warfarin dose response was calculated using a warfarin sensitivity index (WSI) defined as the steady-state INR divided by the mean daily warfarin dose. The primary outcome was the change in WSI from hepatitis C treatment initiation to completion. RESULTS The final sample consisted of 271 patients. The WSI decreased 23% from a mean baseline value of 0.53 to 0.39 (decrease of 0.14; 95% CI = 0.11 to 0.16; P < 0.001). OBV-PTV/r-DSV produced a significantly greater decrease than any sofosbuvir regimen. Concurrent ribavirin accounted for an additional decrease in warfarin sensitivity of -0.09 (95% CI = -0.06 to -0.12; P < 0.001). The percentage of subtherapeutic INR results increased from 26% prior to hepatitis C treatment to 58% during treatment. CONCLUSIONS Results indicate a clinically significant reduction in warfarin dose-response when hepatitis C treatment regimens were added to warfarin. They were most profound with OBV-PTV/r-DSV. Ribavirin was associated with an additive effect. Clinicians should be aware of this potential drug interaction to closely monitor and minimize subtherapeutic levels of anticoagulation.
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Affiliation(s)
| | | | | | - Amanda L Boese
- 1 Minneapolis VA Health Care System, Minneapolis, MN, USA
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Hamberg AK, Wadelius M, Friberg LE, Biss TT, Kamali F, Jonsson EN. Characterizing variability in warfarin dose requirements in children using modelling and simulation. Br J Clin Pharmacol 2015; 78:158-69. [PMID: 24330000 PMCID: PMC4168390 DOI: 10.1111/bcp.12308] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 11/25/2013] [Indexed: 01/14/2023] Open
Abstract
Aims Although genetic, clinical and demographic factors have been shown to explain approximately half of the inter-individual variability in warfarin dose requirement in adults, less is known about causes of dose variability in children. This study aimed to identify and quantify major genetic, clinical and demographic sources of warfarin dose variability in children using modelling and simulation. Methods Clinical, demographic and genetic data from 163 children with a median age of 6.3 years (range 0.06–18.9 years), covering over 183 years of warfarin therapy and 6445 INR observations were used to update and optimize a published adult pharmacometric warfarin model for use in children. Results Genotype effects in children were found to be comparable with what has been reported for adults, with CYP2C9 explaining up to a four-fold difference in dose (CYP2C9 *1/*1 vs. *3/*3) and VKORC1 explaining up to a two-fold difference in dose (VKORC1 G/G vs. A/A), respectively. The relationship between bodyweight and warfarin dose was non-linear, with a three-fold difference in dose for a four-fold difference in bodyweight. In addition, age, baseline and target INR, and time since initiation of therapy, but not CYP4F2 genotype, had a significant impact on typical warfarin dose requirements in children. Conclusions The updated model provides quantitative estimates of major clinical, demographic and genetic factors impacting on warfarin dose variability in children. With this new knowledge more individualized dosing regimens can be developed and prospectively evaluated in the pursuit of improving both efficacy and safety of warfarin therapy in children.
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Affiliation(s)
- Anna-Karin Hamberg
- Department of Medical Sciences, Clinical Pharmacology, Uppsala University, Uppsala, Sweden
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Xu H, Su S, Tang W, Wei M, Wang T, Wang D, Ge W. Comparison of the Performance of the Warfarin Pharmacogenetics Algorithms in Patients with Surgery of Heart Valve Replacement and Heart Valvuloplasty. Thromb Res 2015; 136:552-9. [DOI: 10.1016/j.thromres.2015.06.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 06/12/2015] [Accepted: 06/30/2015] [Indexed: 12/14/2022]
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Peng Q, Huang S, Chen X, Yuan Y, Yu Y, Tao L, Zhang Z, Xu M. Validation of warfarin pharmacogenetic algorithms in 586 Han Chinese patients. Pharmacogenomics 2015; 16:1465-74. [PMID: 26255607 DOI: 10.2217/pgs.15.87] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AIM To compare the accuracy of the nine selected algorithms for predicting warfarin dose with 586 Han Chinese patients. MATERIALS & METHODS Genotyping of VKORC1 1639G>A, CYP2C9*2 and CYP2C9*3 variants was performed. Both the mean absolute error and ideal estimation value were used for comparison. RESULTS The top three performers were from East Asians. The algorithms from Caucasians generally performed better in the medium-dose subgroup (>3 and <7 mg/day), while the algorithms from East Asians generally performed better in the low-dose subgroup (≤ 3 mg/day). None of the algorithms performed well in the high-dose subgroup (≥ 7 mg/day). CONCLUSION Algorithms built for specific ethnic groups and preassigned-dose groups are suggested for better prediction.
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Affiliation(s)
- Qi Peng
- Cardiac Surgery, Wuhan Asia Heart Hospital, 753 Jinghan Ave, Jianghan District, Wuhan, Hubei, 430022, China
| | - Shujun Huang
- Hubei Vidagen Gene Technology Co., Ltd, Building C6-208, 666 Gaoxin Ave, Donghu High-Tech Developmental District, Wuhan, Hubei, 430075, China
| | - Xiaoying Chen
- Department of Cardiology, Wuhan Asia Heart Hospital, 753 Jinghan Ave, Jianghan District, Wuhan, Hubei, 430022, China
| | - Yayan Yuan
- Hubei Vidagen Gene Technology Co., Ltd, Building C6-208, 666 Gaoxin Ave, Donghu High-Tech Developmental District, Wuhan, Hubei, 430075, China
| | - Yajun Yu
- Hubei Vidagen Gene Technology Co., Ltd, Building C6-208, 666 Gaoxin Ave, Donghu High-Tech Developmental District, Wuhan, Hubei, 430075, China
| | - Liang Tao
- Cardiac Surgery, Wuhan Asia Heart Hospital, 753 Jinghan Ave, Jianghan District, Wuhan, Hubei, 430022, China
| | - Zhenlu Zhang
- Clinical Test Center, Wuhan Asia Heart Hospital, 753 Jinghan Ave, Jianghan District, Wuhan, Hubei, 430022, China
| | - Mousheng Xu
- Hubei Vidagen Gene Technology Co., Ltd, Building C6-208, 666 Gaoxin Ave, Donghu High-Tech Developmental District, Wuhan, Hubei, 430075, China
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Warfarin Metabolites in Patients Following Cardiac Valve Implantation: A Contribution of Clinical and Genetic Factors. Cardiovasc Drugs Ther 2015; 29:257-64. [PMID: 25986145 DOI: 10.1007/s10557-015-6591-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Warfarin, a racemic mixture of S- and R-enantiomers, is the cornerstone of therapy in patients following cardiac valve replacement. S-warfarin is metabolized to 7-S-hydroxywarfarin by the cytochrome P450 isoform 2C9 encoded by CYP2C9 gene. R-warfarin is metabolized by multiple cytochromes P450. We sought to assess the impact of clinical and genetic factors on circulating warfarin metabolites following valve implantation. MATERIAL AND METHODS Venous blood was collected from 120 patients after 3 months since elective mitral and/or aortic valve replacement. Plasma S-warfarin, R-warfarin, S-7-hydroxywarfarin, and R-7-hydroxywarfarin were determined using high-performance liquid chromatography. The S-7-hydroxywarfarin/S-warfarin and S-warfarin/R-warfarin (S/R) ratios, along with warfarin sensitivity index (WSI), defined as INR/S-warfarin ratio, were calculated. Vitamin K epoxide reductase complex subunit 1 (VKORC1) c.-1639A, CYP2C9*3 and CYP2C9*2 alleles were determined using real-time polymerase chain reaction. RESULTS The S-warfarin was higher in former smokers (p = 0.047) and the VKORC1 c.-1639A allele carriers (p < 0.0001). The S-7-hydroxywarfarin was lower in carriers of the VKORC1 c.-1639A allele (p = 0.0005) and CYP2C9*3 (p = 0.047). The S-7-hydroxywarfarin/S-warfarin ratio was lower in the carriers of CYP2C9*3 (p = 0.008), but not in those with VKORC1 -c.1639A allele. The S/R ratio was higher in patients with hypertension (p = 0.01). The independent predictors of elevated S/R ratio defined as the upper quartile were diabetes (p = 0.045), CYP2C9*3 (p < 0.0001) and CYP2C9*2 (p = 0.0002). The independent predictors of elevated WSI were current smoking (p = 0.049), implantation of mechanical valve (p = 0.006) and VKORC1c.-1639A allele (p = 0.007). CONCLUSION We conclude that not only genetic, but also several clinical factors affect warfarin metabolites in patients following cardiac valve implantation.
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McMillin GA, Vazquez SR, Pendleton RC. Current challenges in personalizing warfarin therapy. Expert Rev Clin Pharmacol 2014; 4:349-62. [DOI: 10.1586/ecp.11.15] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Irwin AN, McCool KH, Delate T, Witt DM. Assessment of warfarin dosing requirements after bariatric surgery in patients requiring long-term warfarin therapy. Pharmacotherapy 2013; 33:1175-83. [PMID: 23744816 DOI: 10.1002/phar.1307] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
STUDY OBJECTIVE To quantify the change in weekly warfarin dose after bariatric surgery in patients requiring long-term warfarin therapy. DESIGN Retrospective matched-cohort study. SETTING Anticoagulation management service in an integrated health care delivery system. PATIENTS Patients receiving long-term warfarin anticoagulation who underwent bariatric surgery between January 1, 1996, and December 31, 2010 (27 patients), were matched by date of surgery (± 2 years), age (± 5 years), and target international normalized ratio (INR) range to patients receiving long-term anticoagulation therapy who underwent other abdominal surgical procedures: cholecystectomy or endoscopic retrograde cholangiopancreatography (59 patients [control group]). MEASUREMENT AND MAIN RESULTS The main end point was change in postoperative warfarin dose from baseline (preoperative dose), measured at weekly postoperative intervals from weeks 1 to 8 and again at months 3 and 6. After surgery, patients in the bariatric surgery group had statistically significant decreases in weekly warfarin doses compared with preoperative dose at all postoperative time points (week 1 dose vs preoperative dose, p<0.01; doses at all other time points vs preoperative dose, p<0.001), except at 6 months (p>0.05). No statistically significant decreases in warfarin dose were detected at any postoperative time points in the control group. Twenty patients (74.1%) in the bariatric surgery group experienced a 20% or more decrease in weekly warfarin dose compared with 19 patients (32.2%) in the control group (p=0.004). No significant differences in warfarin-related adverse events were noted between groups. CONCLUSION Weekly warfarin doses decreased in the immediate postoperative period in anticoagulated patients after bariatric surgery but returned to their preoperative doses after approximately 6 months. A similar pattern was not observed in patients in the control group who underwent other types of abdominal surgery. Compared with preoperative anticoagulation control, this resulted in reduced anticoagulation control despite close INR monitoring. If a causal relationship between bariatric surgery and warfarin sensitivity is established in future research, developing and validating a postbariatric surgery warfarin-dosing algorithm would be valuable.
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Affiliation(s)
- Adriane N Irwin
- Pharmacy Department, Kaiser Permanente Colorado, Aurora, Colorado, USA
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20
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Clinical impact of temporary therapy interruptions on anticoagulation control in patients treated with warfarin. Am J Ther 2012; 20:267-74. [PMID: 23011173 DOI: 10.1097/mjt.0b013e31824ea644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This retrospective cohort study was completed to describe the impact of short-term therapy interruptions on anticoagulation control in patients receiving warfarin. Patients seen in a pharmacist-managed anticoagulation clinic were included if they were on a stable warfarin dose and then underwent a planned interruption in therapy. Patients were excluded if phytonadione was administered before the interruption or if medications known to interact with warfarin were altered during the interruption. Data were analyzed for 2 groups: (1) patients with a single interruption in therapy (group 1) and (2) patients with a single interruption in therapy plus patients with an extended interruption in therapy (group 2). The primary endpoint was the change in weekly maintenance warfarin dose from preinterruption to postinterruption. Evaluation of 199 patients resulted in 31 interruptions in group 1 and 34 interruptions in group 2. A change in dose was required in 58% of patients in group 1 and 56% of patients in group 2. The mean absolute change in dose was 2.03 ± 2.79 mg (P < 0.003) in group 1 and 1.96 ± 2.72 mg (P < 0.002) in group 2. For the majority of patients, the dose change represented <10% of their preinterruption weekly dose. Of patients requiring a dose change, 50% required an increase in dose. In conclusion, close follow-up is warranted after a warfarin therapy interruption as dose adjustments will likely be needed to regain anticoagulation control and the direction of this dose change cannot be predicted.
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Stafford L, Peterson GM, Bereznicki LRE, Jackson SL, Tienen ECV, Angley MT, Bajorek BV, McLachlan AJ, Mullan JR, Misan GMH, Gaetani L. Clinical Outcomes of a Collaborative, Home-Based Postdischarge Warfarin Management Service. Ann Pharmacother 2011; 45:325-34. [DOI: 10.1345/aph.1p617] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Background: Warfarin remains a high-risk drug for adverse events, especially following discharge from the hospital. New approaches are needed to minimize the potential for adverse outcomes during this period. Objective: To evaluate the clinical outcomes of a collaborative, home-based postdischarge warfarin management service adapted from the Australian Home Medicines Review (HMR) program. Methods: In a prospective, nonrandomized controlled cohort study, patients discharged from the hospital and newly initiated on or continuing warfarin therapy received either usual care (UC) or a postdischarge service (PDS) of 2 or 3 home visits by a trained, HMR-accredited pharmacist in their first 8 to 10 days postdischarge. The PDS involved point-of-care international normalized ratio (INR) monitoring, warfarin education, and an HMR, in collaboration with the patient's general practitioner and community pharmacist. The primary outcome measure was the combined incidence of major and minor hemorrhagic events in the 90 days postdischarge. Secondary outcome measures included the incidences of thrombotic events, combined hemorrhagic and thombotic events, unplanned and warfarin-related hospital readmissions, death, INR control, and persistence with therapy al 8 and 90 days postdischarge. Results: The PDS (n = 129) was associated with statistically significantly decreased rates of combined major and minor hemorrhagic events to day 90 (5.3% vs 14.7%; p = 0.03) and day 8 (0.9% vs 7.2%; p = 0.01) compared with UC (n = 139). The rate of combined hemorrhagic and thrombotic events to day 90 also decreased (6.4% vs 19.0%; p = 0.008) and persistence with warfarin therapy improved (95.4% vs 83.6%; p = 0.004). No significant differences in readmission and death rates or INR control were demonstrated. Conclusions: This study demonstrated the ability of appropriately trained accredited pharmacists working within the Australian HMR framework to reduce adverse events and improve persistence In patients taking warfarin following hospital discharge. Widespread implementation of such a service has the potential to enhance medication safety along the continuum of care. KEY WORDS: adverse drug events, community pharmacy services, international normalized ratio, patient discharge, warfarin.
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Affiliation(s)
- Leanne Stafford
- Unit for Medication Outcomes Research and Education, School of Pharmacy, University of Tasmania, Hobart, Tasmania, Australia
| | - Gregory M Peterson
- Head of School, Unit for Medication Outcomes Research and Education, School of Pharmacy, University of Tasmania
| | - Luke RE Bereznicki
- Unit for Medication Outcomes Research and Education, School of Pharmacy, University of Tasmania
| | - Shane L Jackson
- Unit for Medication Outcomes Research and Education, School of Pharmacy, University of Tasmania
| | - Ella C van Tienen
- Unit for Medication Outcomes Research and Education, School of Pharmacy, University of Tasmania
| | - Manya T Angley
- Sansom Institute for Health Research, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia
| | - Beata V Bajorek
- University of Sydney and Department of Pharmacy and Clinical Pharmacology (Pharmacy Research Unit), Royal North Shore Hospital, Northern Sydney Central Coast Area Health Service, Sydney, Australia
| | | | - Judy R Mullan
- Graduate School of Medicine, University of Wollongong, New South Wales, Australia
| | - Gary MH Misan
- Spencer Gulf Rural Health School, University of South Australia and University of Adelaide, Adelaide, Australia
| | - Luigi Gaetani
- Department of Pharmacy, Wollongong Hospital and Graduate School of Medicine, University of Wollongong
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Abstract
Warfarin has long been the mainstay of oral anticoagulation therapy for the treatment and prevention of venous and arterial thrombosis. The narrow therapeutic index of warfarin, and the complex number of factors that influence international normalized ratio (INR) response, makes optimization of warfarin therapy challenging. Determination of the appropriate warfarin dose during initiation and maintenance therapy requires an understanding of patient factors that influence dose response: age, body weight, nutritional status, acute and chronic disease states, and changes in concomitant drug therapy and diet. This review will examine specific clinical factors that can affect the pharmacokinetics and pharmacodynamics of warfarin, as well as the role of pharmacogenetics in optimizing warfarin therapy.
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Affiliation(s)
- Pamela J. White
- Pharmacy Clinical Specialist, Legacy Health Anticoagulation Clinics, Portland, OR, USA
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Lenzini P, Wadelius M, Kimmel S, Anderson JL, Jorgensen AL, Pirmohamed M, Caldwell MD, Limdi N, Burmester JK, Dowd MB, Angchaisuksiri P, Bass AR, Chen J, Eriksson N, Rane A, Lindh JD, Carlquist JF, Horne BD, Grice G, Milligan PE, Eby C, Shin J, Kim H, Kurnik D, Stein CM, McMillin G, Pendleton RC, Berg RL, Deloukas P, Gage BF. Integration of genetic, clinical, and INR data to refine warfarin dosing. Clin Pharmacol Ther 2010; 87:572-8. [PMID: 20375999 PMCID: PMC2858245 DOI: 10.1038/clpt.2010.13] [Citation(s) in RCA: 182] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Well-characterized genes that affect warfarin metabolism (cytochrome P450 (CYP) 2C9) and sensitivity (vitamin K epoxide reductase complex 1 (VKORC1)) explain one-third of the variability in therapeutic dose before the international normalized ratio (INR) is measured. To determine genotypic relevance after INR becomes available, we derived clinical and pharmacogenetic refinement algorithms on the basis of INR values (on day 4 or 5 of therapy), clinical factors, and genotype. After adjusting for INR, CYP2C9 and VKORC1 genotypes remained significant predictors (P < 0.001) of warfarin dose. The clinical algorithm had an R(2) of 48% (median absolute error (MAE): 7.0 mg/week) and the pharmacogenetic algorithm had an R(2) of 63% (MAE: 5.5 mg/week) in the derivation set (N = 969). In independent validation sets, the R(2) was 26-43% with the clinical algorithm and 42-58% when genotype was added (P = 0.002). After several days of therapy, a pharmacogenetic algorithm estimates the therapeutic warfarin dose more accurately than one using clinical factors and INR response alone.
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Affiliation(s)
- P Lenzini
- Department of Internal Medicine, Washington University, St Louis, Missouri, USA
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Meijer K, Kim YK, Schulman S. Decreasing warfarin sensitivity during the first three months after heart valve surgery: Implications for dosing. Thromb Res 2010; 125:224-9. [DOI: 10.1016/j.thromres.2009.02.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 02/23/2009] [Accepted: 02/26/2009] [Indexed: 11/27/2022]
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Validation of VKORC1 and CYP2C9 genotypes on interindividual warfarin maintenance dose: a prospective study in Chinese patients. Pharmacogenet Genomics 2009; 19:226-34. [PMID: 19177029 DOI: 10.1097/fpc.0b013e328326e0c7] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES To develop a warfarin-dosing algorithm that could be combined with pharmacogenomic and demographic factors, and to evaluate its effectiveness in a randomized prospective controlled clinical trial. METHODS A pharmacogenetics-based dosing model was derived using retrospective data from 266 Chinese patients and multiple linear regression analysis. To prospectively validate this model, 156 patients with an operation of heart valve replacement were enrolled and randomly assigned to the group of pharmacogenetics-guided or traditional dosing for warfarin therapy. All patients were followed up for 50 days after initiation of warfarin therapy. The log-rank test was compared with the time-to-event (Kaplan-Meier) curves. Cox proportional hazards-regression model was used to assess the hazard ratio of the time to reach stable dose. RESULTS The linear regression model derived from the pharmacogenomic model correlated with 54.1% of warfarin dosing variance. The final multiple linear regression model included age, body surface area, VKORC1, and CYP2C9 genotype. The study showed that the hazard ratio for the time to reach stable dose was 1.932 for the traditional dosing group versus the model-based group and a close and highly significant relationship was observed to exist between the predicted and the actual warfarin dose (R=0.454). CONCLUSION A pharmacogenetics-based dosing algorithm has been developed for improvement in the time to reach the stable dosing of warfarin. This model may be useful in helping the clinicians to prescribe warfarin with greater safety and efficiency.
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Effect of CYP2C9 and VKORC1 genotypes on early-phase and steady-state warfarin dosing in Korean patients with mechanical heart valve replacement. Pharmacogenet Genomics 2009; 19:103-12. [PMID: 19077919 DOI: 10.1097/fpc.0b013e32831a9ae3] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The effect of CYP2C9 and vitamin K epoxide reductase complex subunit 1 (VKORC1) genotypes was evaluated for the early-phase and steady-state warfarin dosing in Korean patients with mechanical heart valve replacement. METHODS The genotypes of CYP2C9 variants including CYP2C9*3, CYP2C9*13, and CYP2C9*14, and VKORC1 1173C>T were assessed for the association with warfarin dosing in 265 patients whose data were collected for warfarin dose; international normalized ratio (INR), comedication, comorbidity, and other clinical characteristics. RESULTS In the early phase of warfarin therapy, the combined genotypes of CYP2C9 and VKORC1 caused statistically significant difference in warfarin dose from day 7 of warfarin dosing and the subsequent time course of dose increase showed significant difference among the three different genotypes (P<0.001). Compared with patients with CYP2C9 wild type, the patients with heterozygous CYP2C9 variants have delayed time to reach stable dose [adjusted hazard ratio (HRadj): 0.48; 95% confidence interval (CI): 0.27-0.85] and tended to have high risk for the first INR greater than 3.5 (HRadj: 1.64; 95% CI: 0.98-2.75). The patients with the VKORC1 CT genotype showed no significant difference in the time to reach stable dose but statistically significant low HR for time to first INR greater than 3.5 compared with those with VKORC1 TT genotype (HRadj: 0.25; 95% CI: 0.13-0.51). The observed warfarin maintenance dose was best explained by a model including covariates of age, weight, concurrent congestive heart failure/cardiomyopathy, INR-increasing drugs, aspirin, dietary supplements, and CYP2C9 and VKORC1 genotypes (R=0.56). CONCLUSION The heterozygous CYP2C9 and VKORC1 genotypes influence warfarin dosing in an early phase as well as steady state of warfarin therapy in Korean patients with mechanical heart valve replacement.
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Homme MB, Reynolds KK, Valdes R, Linder MW. Dynamic Pharmacogenetic Models in Anticoagulation Therapy. Clin Lab Med 2008; 28:539-52. [DOI: 10.1016/j.cll.2008.10.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Schulman S, El Bouazzaoui B, Eikelboom JW, Zondag M. Clinical factors influencing the sensitivity to warfarin when restarted after surgery. J Intern Med 2008; 263:412-9. [PMID: 18205763 DOI: 10.1111/j.1365-2796.2007.01913.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND OBJECTIVE Resumption of oral anticoagulation after surgery may result in a different maintenance dose of warfarin than before the procedure. Knowledge of the clinical determinants of postoperative response could help avoid excessive anticoagulation in sensitive patients or avoid extended delays in achieving a therapeutic level in resistant patients. DESIGN Retrospective review. SUBJECTS Two hundred warfarin-treated patients who were managed by our clinic for surgery. OUTCOME Two independent adjudicators classified the postoperative response to warfarin as Resistant, Normal or Sensitive, based on previous maintenance dose, international normalized ratio (INR) on the day of resumption, number of days until INR of >1.9 and doses of warfarin given. A third adjudicator resolved disagreements. Clinical data were extracted from the patient records and correlated with the response. RESULTS Interobserver agreement for classification of postoperative response was moderate (weighted kappa 0.46) with 37 (18.5%) considered resistant, 135 (67.5%) normal, 27 (13.5%) sensitive and one patient was not classifiable. The main type of surgery was cardiac. In univariable analysis only addition of amiodarone after surgery was associated with a sensitive response (P = 0.04). After adjustment for all other factors with an ordered categorical response, amiodarone remained as the sole independent risk factor (P = 0.02) for a sensitive response, odds ratio 0.41 (95% confidence interval 0.19-0.89) for Normal instead of Sensitive or for Resistant instead of Normal. CONCLUSION Altered sensitivity to warfarin occurs in about one-third of patients after surgery and can be predicted by the introduction of concomitant amiodarone therapy but not by patient factors or the nature of the procedure. Changes in concomitant medications after surgery should alert doctors of the potential for increased sensitivity to warfarin.
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Affiliation(s)
- S Schulman
- Department of Medicine, McMaster University, Hamilton, ON, Canada.
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Caraco Y, Blotnick S, Muszkat M. CYP2C9 Genotype-guided Warfarin Prescribing Enhances the Efficacy and Safety of Anticoagulation: A Prospective Randomized Controlled Study. Clin Pharmacol Ther 2007; 83:460-70. [PMID: 17851566 DOI: 10.1038/sj.clpt.6100316] [Citation(s) in RCA: 305] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Warfarin anticoagulation effect is characterized by marked variability, some of which has been attributed to CYP2C9 polymorphisms. This study prospectively examines whether a priori knowledge of CYP2C9 genotype may improve warfarin therapy. Patients were randomly assigned to receive warfarin by a validated algorithm ("control", 96 patients) or CYP2C9 genotype-adjusted algorithms ("study", 95 patients). The first therapeutic international normalized ratio and stable anticoagulation were reached 2.73 and 18.1 days earlier in the study group, respectively (P<0.001). The faster rate of initial anticoagulation was driven by a 28% higher daily dose in the study group (P<0.001). Study group patients spent more time within the therapeutic range (80.4 vs 63.4%, respectively, P<0.001) and experienced less minor bleeding (3.2 vs 12.5%, P<0.02, respectively). In conclusion, CYP2C9 genotype-guided warfarin therapy is more efficient and safer than the "average-dose" protocol. Future research should focus on construction of algorithms that incorporate other polymorphisms (VKORC1), host factors, and environmental influences.
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Affiliation(s)
- Y Caraco
- Clinical Pharmacology Unit, Division of Medicine, Hadassah University Hospital, Jerusalem, Israel.
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Millican EA, Lenzini PA, Milligan PE, Grosso L, Eby C, Deych E, Grice G, Clohisy JC, Barrack RL, Burnett RSJ, Voora D, Gatchel S, Tiemeier A, Gage BF. Genetic-based dosing in orthopedic patients beginning warfarin therapy. Blood 2007; 110:1511-5. [PMID: 17387222 PMCID: PMC1975838 DOI: 10.1182/blood-2007-01-069609] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Accepted: 02/26/2007] [Indexed: 11/20/2022] Open
Abstract
High variability in drug response and a narrow therapeutic index complicate warfarin therapy initiation. No existing algorithm provides recommendations on refining the initial warfarin dose based on genetic variables, clinical data, and international normalized ratio (INR) values. Our goal was to develop such an algorithm. We studied 92 patients undergoing primary or revision total hip or knee replacement. From each patient we collected a blood sample, clinical variables, current medications, and preoperative and postoperative laboratory values. We genotyped for polymorphisms in the cytochrome P450 (CYP) 2C9 and vitamin K epoxide reductase (VKORC1) genes. Using stepwise regression, we developed a model for refining the warfarin dose after the third warfarin dose. The algorithm explained four fifths of the variability in therapeutic dose (R(2)(adj) of 79%). Significant (P > .05) predictors were INR value after 3 doses (47% reduction per 0.25-unit rise), first warfarin dose (+7% per 1 mg), CYP2C9*3 and CYP2C9*2 genotype (-38% and -17% per allele), estimated blood loss (interacting with INR(3)), smoking status (+20% in current smokers), and VKORC1 (-11% per copy of haplotype A). If validated, this model should provide a safer, more effective process for initiating warfarin therapy.
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Affiliation(s)
- Eric A Millican
- Department of Medicine, Washington University in St Louis, MO 63110, USA
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Dager WE, Dougherty JA, Nguyen PH, Militello MA, Smythe MA. Heparin-Induced Thrombocytopenia: Treatment Options and Special Considerations. Pharmacotherapy 2007; 27:564-87. [PMID: 17381384 DOI: 10.1592/phco.27.4.564] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Heparin-induced thrombocytopenia (HIT) is an immune-mediated adverse effect that typically manifests several days after the start of heparin therapy, although both rapid- and delayed-onset HIT have been described. Its most serious complication is thrombosis. Although not all patients develop thrombosis, it can be life threatening. The risk of developing HIT is related to many factors, including the type of heparin product administered, route of administration, duration of therapy, patient population, and previous exposure to heparin. The diagnosis of HIT is typically based on clinical presentation, exposure to heparin, and presence of thrombocytopenia with or without thrombosis. Antigen and activation laboratory assays are available to support the diagnosis of HIT. However, because of the limited sensitivity and specificity of these assays, bedside probability scales for HIT were developed. When HIT is suspected, prompt cessation of all heparin therapy is necessary, along with initiation of alternative anticoagulant therapy. Two direct thrombin inhibitors--argatroban and lepirudin--are approved for the management of HIT in the United States, and bivalirudin is approved for use in patients with HIT who are undergoing percutaneous coronary intervention. Other agents, although not approved to manage HIT, have also been used; however, their role in therapy requires further evaluation. A comprehensive HIT management strategy involves the evaluation of numerous factors. Many patients, including those undergoing coronary artery bypass surgery, those with acute coronary syndromes, those with hepatic or renal insufficiency, and children, require special attention. Clinicians must become familiar with the available information on this serious adverse effect and its treatment so that optimum patient management strategies may be formulated.
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Affiliation(s)
- William E Dager
- Department of Pharmaceutical Services, University of California-Davis Medical Center, California 95817-2201, USA.
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Current awareness: Pharmacoepidemiology and drug safety. Pharmacoepidemiol Drug Saf 2006. [DOI: 10.1002/pds.1182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Bereznicki LR, Jackson SL, Peterson GM. Comment: increased sensitivity to warfarin after heart valve replacement. Ann Pharmacother 2006; 40:1476-7. [PMID: 16835315 DOI: 10.1345/aph.1g407a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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