Correction of Warfarin Coagulopathy for Non-bleeding Patients in the Outpatient Setting at an Ambulatory Care Organization: Application of Vitamin K Guidance.

BACKGROUND: Warfarin is an effective anticoagulant but requires close International Normalized Ratio (INR) monitoring and may occasionally require correction of excessive anticoagulation. Current guidelines provide limited practical guidance on the administration of vitamin K for the management of supratherapeutic INR levels ≥ 5.0 in non-bleeding outpatients. OBJECTIVE: Based on expert consensus and guidelines, the Atrius Health Anticoagulation Management Services (AMS) has developed internal guidance for oral vitamin K use in highly selected populations. This study will describe the internal guidance for oral vitamin K use and present associated results and clinical outcomes. METHODS: Episodes with INR > 5.0 were included, with vitamin K considered for episodes with INR ≥ 6. Moreover, compelling indications and exclusions to select ideal patients for vitamin K intervention were also defined. RESULTS: Overall, episodes were managed conservatively; of the 246 collected episodes of excessive anticoagulation, in 18 episodes (7%), patients received vitamin K, and in 228 (93%) episodes, patients did not receive vitamin K. The mean index INR was 6.0 (range 5.0 - 10.5, SD 1.07), with nearly 57% of episodes achieving INR correction and 15% of episodes developing INR overcorrection. High thrombotic risk patients, regardless of hemorrhagic risk, were less likely to receive vitamin K. Three episodes (1.2%) resulted in bleeding complications. No thrombotic complications occurred during the 30-day follow-up of the index INR value ≥ 5.0. CONCLUSION: Our internal guidance is a novel, standardized approach that serves as a decision support tool for the management of warfarin-associated coagulopathy and vitamin K intervention using patient-specific characteristics and index INR values. This guidance may assist other anticoagulation management services with practical applications and require validation in a prospective clinical trial.

Stepped-wedge randomised trial to evaluate population health intervention designed to increase appropriate anticoagulation in patients with atrial fibrillation.

BACKGROUND: Clinical guidelines recommend anticoagulation for patients with atrial fibrillation (AF) at high risk of stroke; however, studies report 40% of this population is not anticoagulated. OBJECTIVE: To evaluate a population health intervention to increase anticoagulation use in high-risk patients with AF. METHODS: We used machine learning algorithms to identify patients with AF from electronic health records at high risk of stroke (CHA2DS2-VASc risk score ≥2), and no anticoagulant prescriptions within 12 months. A clinical pharmacist in the anticoagulation service reviewed charts for algorithm-identified patients to assess appropriateness of initiating an anticoagulant. The pharmacist then contacted primary care providers of potentially undertreated patients and offered assistance with anticoagulation management. We used a stepped-wedge design, evaluating the proportion of potentially undertreated patients with AF started on anticoagulant therapy within 28 days for clinics randomised to intervention versus usual care. RESULTS: Of 1727 algorithm-identified high-risk patients with AF in clinics at the time of randomisation to intervention, 432 (25%) lacked evidence of anticoagulant prescriptions in the prior year. After pharmacist review, only 17% (75 of 432) of algorithm-identified patients were considered potentially undertreated at the time their clinic was randomised to intervention. Over a third (155 of 432) were excluded because they had a single prior AF episode (transient or provoked by serious illness); 36 (8%) had documented refusal of anticoagulation, the remainder had other reasons for exclusion. The intervention did not increase new anticoagulant prescriptions (intervention: 4.1% vs usual care: 4.0%, p=0.86). CONCLUSIONS: Algorithms to identify underuse of anticoagulation among patients with AF in healthcare databases may not capture clinical subtleties or patient preferences and may overestimate the extent of undertreatment. Changing clinician behaviour remains challenging.

Resource utilization and hospital readmission associated with gastrointestinal bleeding in patients with continuous-flow left ventricular assist devices.

Gastrointestinal bleeding (GIB) occurs in up to 40% of patients with continuous-flow (CF) left ventricular assist devices (LVADs). We sought to identify targets to improve hospital resource utilization and decrease readmissions after GIB. We performed a single-center, retrospective analysis of LVAD-associated GIB resulting in hospital admission between July 2011 and April 2014. Follow-up data were collected through March 2015. We analyzed 57 admissions for GIB in 23 patients. One or more diagnostic imaging study was performed in 47% of admissions, with a definite or probable source of GIB identified in 23%. A total of 76 endoscopies were performed (≥ 1 endoscopy in 79% of admissions, ≥ 2 in 42%). Definite or probable bleeding sources were identified in 25% and 12% of endoscopies, respectively. Patients who underwent multiple endoscopies were no more likely to have a bleeding source identified (OR 1.48; 95% CI 0.50-4.32; p = 0.59) and had longer hospital stays (11.1 vs. 7.8 days, p < 0.02). Readmission rates for GIB at 30 and 90 days were 33% and 53%, respectively. A decrease in antiplatelet regimen at discharge was associated with lower rate of readmission for GIB (OR 0.16; 95% CI 0.03-0.82; p = 0.03) or any cause (OR 0.21; 95% CI 0.05-0.85; p = 0.04) at 30 and 90 days. GIB in patients with CF-LVADs is associated with significant in-hospital resource utilization and high rates of readmission. Imaging and endoscopy are common, but have low diagnostic yield and infrequently result in successful intervention. Strategies to reduce resource utilization and prevent readmission are warranted.

Prospective evaluation of a bivalirudin to warfarin transition nomogram.

Bivalirudin may cause a falsely prolonged international normalized ratio (INR) that complicates the discontinuation of bivalirudin when used as a bridge to warfarin. To prospectively validate our novel bivalirudin to warfarin transition nomogram, adult patients who received bivalirudin as a bridge to warfarin between July 2015 and June 2016 were prospectively evaluated, utilizing our predictive nomogram. The major outcome of our analysis was the correlation between the predicted change in INR upon bivalirudin discontinuation based on the nomogram, and the actual change in INR upon bivalirudin discontinuation. The major outcome was analyzed using the Pearson's correlation test. A Pearson's correlation coefficient >0.6 was considered to be a strong correlation. Bivalirudin was used as a bridge to warfarin in 29 patients. The majority of patients (86%) included in the analysis had a ventricular assist device. The median initial bivalirudin rate was 0.07 mg/kg/h and the mean increase in INR when starting bivalirudin was 0.6. The mean final weight-based bivalirudin rate was 0.08 mg/kg/h and the mean change in INR after stopping bivalirudin was 0.7. The Pearson correlation coefficient between the predicted change in INR upon bivalirudin discontinuation and the actual change in INR upon bivalirudin discontinuation was 0.86 (p < 0.001). After bivalirudin discontinuation, 68% of patients had a therapeutic INR. The results of this prospective analysis successfully validated our novel bivalirudin to warfarin transition nomogram. There was a very strong correlation between the predicted change and actual change in INR upon bivalirudin discontinuation.

Development of a Predictive Nomogram for the Change in PT/INR Upon Discontinuation of Bivalirudin as a Bridge to Warfarin.

Appropriate timing of bivalirudin discontinuation as a bridge to warfarin is complicated, as bivalirudin may cause a falsely prolonged international normalized ratio (INR). The purpose was to evaluate patient and medication characteristics associated with differences in INR prolongation caused by bivalirudin. Adult patients receiving bivalirudin as a bridge to warfarin in 2014 were retrospectively evaluated. Patients were excluded if they had known thrombophilia or inappropriate INR monitoring after discontinuation of bivalirudin. Data recorded included indication for bivalirudin use, bivalirudin dosing, and coagulation assays. Univariate analysis was performed to determine variables associated with a larger change in INR when discontinuing bivalirudin. Variables with P < .3 were included in multivariate analysis. In total, 50 patient admissions were included in the analysis. Patients with ventricular assist devices represented the majority of the patient population (74%). The most common INR goals were 2.0 to 3.0 and 2.5 to 3.5. The mean initial weight-based bivalirudin rate was 0.076 mg/kg/h, and the mean increase in INR when starting bivalirudin was 0.6. The mean final weight-based bivalirudin rate was 0.13 mg/kg/h, and the mean change in INR after stopping bivalirudin was 0.8. On multivariate analysis, factors associated with a larger change in INR after stopping bivalirudin included higher serum creatinine ( P = .033), greater change in INR after initiation of bivalirudin ( P = .028), and higher final bivalirudin rate ( P < .001). The change in INR when starting or stopping bivalirudin appears to be patient specific and dose related. A nomogram was developed to predict the ideal timing of bivalirudin discontinuation. Prospective evaluation of the nomogram is under way.

North American Thrombosis Forum, AF Action Initiative Consensus Document.

The North American Thrombosis Forum Atrial Fibrillation Action Initiative consensus document is a comprehensive yet practical briefing document focusing on stroke and bleeding risk assessment in patients with atrial fibrillation, as well as recommendations regarding anticoagulation options and management. Despite the breadth of clinical trial data and guideline recommendation updates, many clinicians continue to struggle to synthesize the disparate information available. This problem slows the uptake and utilization of updated risk prediction tools and adoption of new oral anticoagulants. This document serves as a practical and educational reference for the entire medical community involved in the care of patients with atrial fibrillation.

Anticoagulation in patients with pulmonary arterial hypertension: An update on current knowledge.

Pulmonary hypertension is a severe clinical condition characterized by molecular and anatomic changes in pulmonary circulation. It is associated with increased pulmonary vascular resistance, which leads to right-sided heart failure if left untreated and, ultimately, death. Treatment of patients with pulmonary arterial hypertension (PAH) involves a complex strategy that takes into consideration disease severity, general and supportive measures, and combination drug regimens. Abnormalities of blood coagulation factors, anti-thrombotic factors, and the fibrinolytic system may contribute to a prothrombotic state in patients with idiopathic PAH. These physiologic changes, in concert with the presence of non-specific risk factors for venous thromboembolism such as heart failure and immobility, are thought to be the basis for oral anticoagulation in PAH. Several observational studies provide helpful information in favor of anticoagulation use in idiopathic PAH but not in other pulmonary hypertension etiologies. Guideline recommendations are based on the lack of prospective comparative trials in this regard. For that reason, large differences exist in the use of anticoagulants in different countries and centers. More studies should be carried out to clarify the risks and the potential benefits of anticoagulant use in a heterogeneous population of patients who are already at considerable life risk.