Assessment of Temporary Warfarin Reversal in Patients With Left Ventricular Assist Devices: the KVAD Study

BACKGROUND

Patients with left ventricular assist devices (LVADs) require interruption of warfarin for invasive procedures, but parenteral bridging is associated with many complications. Four-factor prothrombin complex concentrate (4F-PCC) can temporarily restore hemostasis in patients undergoing anticoagulation with warfarin.

OBJECTIVES

This pilot study evaluated the strategy of using variable-dose 4F-PCC to immediately and temporarily reverse warfarin before invasive procedures without holding warfarin in patients with LVADs. The duration of effect of 4F-PCC on factor levels and time to reestablish therapeutic anticoagulation post procedure were assessed.

METHODS

Adult patients with LVADs and planned invasive procedures were enrolled from a single center. Warfarin was continued uninterrupted. The 4F-PCC dose administered immediately pre-procedure was based on study protocol. International normalized ratio (INR)- and vitamin K-dependent factor levels were collected before and during the 48 hours after 4F-PCC administration. The use of parenteral bridging, International Society for Thrombosis and Haemostasis major and clinically relevant nonmajor bleeding (CRNMB) and thromboembolic events at 7 and 30 days were collected.

RESULTS

In 21 episodes of 4F-PCC reversal, median baseline INR was 2.7 (IQR 2.2-3.2). The median dosage of 4F-PCC administered was 1794 units (IQR 1536-2130). At 24 and 48 hours post 4F-PCC administration, median INRs were 1.8 (IQR 1.7-2.0) and 2.0 (IQR 1.9-2.4). Two patients required postoperative bridging. One patient experienced major bleeding within 72 hours, and 2 experienced CRNMB within 30 days. There were no thromboembolic events. Baseline and post 4F-PCC vitamin K-dependent factor levels corresponded with changes in INR values. The median time to achieve therapeutic INR post-procedure was 2.5 days (IQR, 1-4).

CONCLUSION

Administration of 4F-PCC for temporary reversal of warfarin for invasive procedures in patients with LVADs allowed for continued warfarin dosing with minimal use of post-intervention bridging, limited bleeding and no thromboembolic events.

Multicenter evaluation of left ventricular assist device implantation with or without ECMO bridge in cardiogenic shock

BACKGROUND

The efficacy of extracorporeal membrane oxygenation (ECMO) as a bridge to left ventricular assist device (LVAD) remains unclear, and recipients of the more contemporary HeartMate 3 (HM3) LVAD are not well represented in previous studies. We therefore undertook a multicenter, retrospective study of this population.

METHODS AND RESULTS

INTERMACS 1 LVAD recipients from five U.S. centers were included. In-hospital and one-year outcomes were recorded. The primary outcome was the overall mortality hazard comparing ECMO versus non-ECMO patients by propensity-weighted survival analysis. Secondary outcomes included survival by LVAD type, as well as postoperative and one-year outcomes. One hundred and twenty-seven patients were included; 24 received ECMO as a bridge to LVAD. Mortality was higher in patients bridged with ECMO in the primary analysis (HR 3.22 [95%CI 1.06-9.77], p = 0.039). Right ventricular assist device was more common in the ECMO group (ECMO: 54.2% vs non-ECMO: 11.7%, p < 0.001). Ischemic stroke was higher at one year in the ECMO group (ECMO: 25.0% vs non-ECMO: 4.9%, p = 0.006). Among the study cohort, one-year mortality was lower in HM3 than in HeartMate II (HMII) or HeartWare HVAD (10.5% vs 46.9% vs 31.6%, respectively; p < 0.001) recipients. Pump thrombosis at one year was lower in HM3 than in HMII or HVAD (1.8% vs 16.1% vs 16.2%, respectively; p = 0.026) recipients.

CONCLUSIONS

Higher mortality was observed with ECMO as a bridge to LVAD, likely due to higher acuity illness, yet acceptable one-year survival was seen compared with historical rates. The receipt of the HM3 was associated with improved survival compared with older generation devices.

Impact of as needed heparin boluses on supratherapeutic activated partial thromboplastin time in patients managed with extracorporeal membrane oxygenation

INTRODUCTION

Brigham and Women's Hospital (BWH) historically used titratable weight-based heparin nomograms with as needed boluses managed by extracorporeal membrane oxygenation (ECMO) specialists to achieve a pre-determined goal activated partial thromboplastin time (aPTT). Due to concern amongst providers that as needed boluses may lead to supratherapeutic aPTT's and subsequent bleeding, new nomograms without as needed boluses were implemented. The purpose of this retrospective observational analysis is to provide a comparison in safety and efficacy between the heparin nomograms with as needed boluses and the new nomograms without boluses.

METHODS

Adult patients who were cannulated on ECMO and initiated on an approved heparin bolus nomogram (January 1, 2018-December 31, 2019) or an approved heparin no bolus nomogram (October 20, 2020-March 31, 2021) were screened for inclusion. The major endpoint evaluated was the percentage of supratherapeutic aPTTs, defined as an aPTT above the upper limit of the specified nomogram goal, within the first 72 hours.

RESULTS

A total of 23 patients were included in the bolus nomogram cohort and 9 patients in the no-bolus nomogram cohort. Within the first 72 hours of initiation, there were 11.5% supratherapeutic aPTTs in the bolus group and 5.1% in the no-bolus group (p=0.101). Overall there was one bleeding event in the no-bolus group (11.1%) and seven in the bolus group (30.4%) (p=0.26). There were no thromboembolic events in either group.

CONCLUSION

Overall, there was no difference found in percentage of supratherapeutic aPTTs within the first 72 hours of heparin initation between the bolus and no-bolus nomograms.

One-year retrospective analysis of anti-FXa apixaban and rivaroxaban levels demonstrates utility for management decisions in various urgent and nonurgent clinical situations

OBJECTIVES

Quantification of direct oral anticoagulant (DOAC) plasma levels can guide clinical management, but insight into clinical scenarios surrounding DOAC-calibrated anti-FXa assays is limited.

METHODS

Apixaban- and rivaroxaban-calibrated chromogenic anti-Xa assays performed over a 1-year period were retrospectively analyzed. Patient demographics, DOAC history, concomitant medications, and renal/liver comorbidities were obtained. Indications for testing and associated clinical actions were reviewed. Machine learning (ML) models predicting clinical actions were evaluated.

RESULTS

In total, 371 anti-FXa apixaban and 89 anti-FXa rivaroxaban tests were performed for 259 and 67 patients in recurring urgent (acute bleeding, unplanned procedures) and nonurgent situations, including several scenarios not captured by existing testing recommendations (eg, drug monitoring, recurrent thromboembolic events, bleeding tendency). In urgent settings, andexanet reversal was guided by radiologic and clinical findings over DOAC levels in 14 of 32 instances, while 51% of apixaban patients qualified for nonreversal strategies through the availability of levels. Levels also informed procedure/intervention timing and supported management decisions when DOAC clearance or DOAC target levels were in question. The importance of clinical context was emphasized by exploratory ML models predicting particular clinical actions.

CONCLUSIONS

Although clinical situations are complex, DOAC testing facilitates clinical decision-making, including reversal, justifying more widespread implementation of these assays.

Evaluation of the use of direct oral anticoagulants for the management of heparin-induced thrombocytopenia

Historically, treatment of heparin-induced thrombocytopenia (HIT) includes a non-heparin parenteral anticoagulant with bridging to warfarin once platelets recover. Data supporting the use of direct oral anticoagulants (DOACs) for HIT treatment are limited. Given the paucity of evidence for the use of DOACs in HIT, the aim of this study is to describe the prescribing patterns of DOACs for HIT at our institution. This is a single center, retrospective chart evaluation of patients admitted from January 2017 to October 2020 with a confirmed diagnosis of HIT. Twenty-six patients were identified; 21 patients (81%) received initial parenteral treatment and 5 patients (19.2%) with initial DOAC treatment. The most frequently used DOAC was apixaban at the VTE treatment dose [15 (57.7%)] followed by the reduced dose of apixaban [5 (19.2%)]. Of the patients initially treated with a parenteral agent, 11 (42.3%) were transitioned to a DOAC after platelet recovery, 7 (26.9%) transitioned as platelets were steadily increasing, and 3 (11.5%) transitioned at the time of discharge (prior to platelet recovery). Platelet recovery was achieved in 23 patients (88.5%) at a median of 5 days (IQR 2.8-8.3) after HIT diagnosis. No new thrombotic or bleeding events occurred within 30 days of HIT diagnosis. In our patients treated with a DOAC for HIT, no progression of HIT was observed. Apixaban was the most frequently utilized DOAC. Most patients received a parenteral anticoagulant prior to DOAC initiation. All patients managed with a DOAC as initial treatment achieved platelet recovery within 30 days of HIT diagnosis.

Optimization of DOAC management services in a centralized anticoagulation clinic

Background

In 2017, the Brigham and Women’s Hospital Anticoagulation Management Service (BWH AMS) expanded services to patients on direct oral anticoagulants (DOACs). We have since updated our DOAC management plan and adjusted the workflow of our clinic.

Objectives

This report describes how our DOAC management has evolved and describes key interventions made. Additionally, we report on the results of a survey completed by referring physicians that assessed perspectives regarding centralized DOAC management by BWH AMS pharmacists.

Methods

An analysis was completed of all patients referred to the BWH AMS and the number of interventions completed and documented in our anticoagulation management software. A survey with eight questions was sent to 110 referring physicians (selected based on referring to the AMS within the past 1.5 years).

Results

Over 4 years, 1622 patients on DOACs were referred to the BWH AMS, amounting to 3154 DOAC encounters. A total of 212 interventions for medication procurement, 171 dose adjustment interventions, and 603 coordinated procedure plans were completed. Of the 32 physicians who responded to the survey, many believed that the quality and safety of anticoagulation therapy was improved with BWH AMS management. Despite provider satisfaction with pharmacist‐led care in DOACs, physicians expressed concerns regarding the lack of provider awareness of the clinic and possible duplicative efforts.

Conclusion

We plan to evolve the DOAC clinic model to optimize its clinical and operational value and to improve our delivery of care using electronic tools to move toward a population management approach for DOAC management.

Heparin-induced thrombocytopenia in end-stage renal disease: Reliability of the PF4-heparin ELISA

BACKGROUND

Diagnosing heparin-induced thrombocytopenia (HIT) in patients with end-stage renal disease (ESRD) can be difficult, as they are frequently exposed to heparin and have multiple etiologies for thrombocytopenia.

OBJECTIVE

To correlate 4T scores, IgG heparin-platelet factor 4 (PF4-heparin) ELISA results, and serotonin release assay (SRA) results in patients with ESRD.

METHODS

We performed a retrospective review of patients with ESRD (creatinine clearance < 15 mL/min or on renal replacement therapy [RRT]) who underwent PF4-heparin ELISA testing from October 2015 to September 2019. True-positive PF4s required an intermediate to high 4T score (≥4), a positive SRA, and receipt of treatment for a HIT diagnosis. False-positive PF4s were defined as a positive PF4 with a negative SRA, low 4T score (<4), or lack of treatment for HIT. Indeterminant cases were classified on the basis of clinical assessment by the treating team (eg, hematology or vascular medicine).

RESULTS

Of 254 patients with ESRD (92% on RRT), 29 patients (11.4%) had a positive PF4. Eleven (37.9%) had a confirmed diagnosis of HIT: 10 patients who met all of the above criteria, and one who met the 4T criteria and was treated for HIT but did not have SRA testing due to high clinical suspicion and a positive PF4 test. False-positive PF4 values occurred in 8 patients (27.5%). Of 10 (34.5%) indeterminant cases of patients with a negative SRA but intermediate to high 4T and positive PF4, only 3 patients were treated for HIT, whereas the other 7 were judged not to have HIT as assessed by the treating clinician. In patients with an intermediate to high 4T score and PF4 optical density > 0.4 but negative SRA, who were not treated for HIT, there were no adverse outcomes documented such as new or progressive thrombosis.

CONCLUSION

In our ESRD population, 4T scores and PF4 testing were not predictive of a clinical diagnosis of HIT.

Management of therapeutic unfractionated heparin in COVID-19 patients: A retrospective cohort study

Background

Patients hospitalized with severe acute respiratory syndrome coronavirus 2 infection are at risk for thrombotic complications necessitating use of therapeutic unfractionated heparin (UFH). Full-dose anticoagulation limits requirements for organ support interventions in moderately ill patients with coronavirus disease 2019 (COVID-19). Given this benefit, it is important to evaluate response to therapeutic anticoagulation in this population.

Objectives

The aim of this study was to assess therapeutic UFH infusions and associated bleeding risk in patients with COVID-19.

Patients/Methods

This retrospective cohort study includes patients at Brigham and Women's Hospital, Boston, Massachusetts, receiving weight-based nursing-nomogram titrated UFH infusion during a 10-week surge in COVID-19 hospitalizations. Of 358 patients on therapeutic UFH during this interval, 97 (27.1%) had confirmed COVID-19. Patient characteristics, laboratory values, and information regarding UFH infusion and bleeding events were obtained from the electronic medical record.

Results

Patients who were COVID-19 positive had fewer therapeutic activatrd partial thromboplastin times (aPTTs) compared to COVID-19-negative patients (median rate, 40.0% vs 53.1%; P < .0005). Both major and clinically relevant nonmajor bleeding were increased in COVID-19-positive patients, with major bleeding observed in 10.3% (95% confidence interval [CI], 5.7%-17.9%) of patients who were COVID-19 positive and 3.1% (95% CI, 1.6%-5.9%) of patients who were COVID-19 negative (P < .005). In logistic regression, bleeding events were associated with receiving UFH for longer than 7 days, but not platelet count, coagulation, or inflammatory measurements.

Conclusions

Our data indicate a higher incidence of bleeding complications in patients with COVID-19 receiving weight-based nursing-nomogram titrated UFH infusions despite a higher prevalence of subtherapeutic aPTTs in this population. These data underscore the need for prospective studies aimed at improving the quality and safety of therapeutic anticoagulation in patients with COVID-19.

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.

Evaluation of oral factor Xa inhibitor-associated extracranial bleeding reversal with andexanet alfa

INTRODUCTION

A reversal agent for factor Xa (FXa) inhibitors, andexanet alfa, was Food and Drug Administration approved without extensive study of clinical effectiveness, due to an overwhelming demand for FXa inhibitor reversal. In this study, we aimed to describe patient selection, clinical effectiveness, and safety of FXa inhibitor reversal with andexanet alfa in patients presenting with extracranial bleeding.

METHODS

Consecutive patients who received andexanet alfa for reversal of FXa inhibitor-associated extracranial hemorrhage were identified. The primary outcome of interest was hemostatic efficacy, assessed using the Sarode et al criteria. Secondary outcomes of interest included incidence of thrombotic episodes post-reversal until discharge and in-hospital mortality.

RESULTS

Twenty-one patients met the inclusion criteria (61.9% male, mean age: 73 years). Anticoagulation reversal with andexanet alfa was deemed effective (excellent [n = 3], good [n = 7]) in 10 (47.6%) patients, and poor in 11 patients (52.4%). Eight (38.1%) patients died, of which three were surgically managed, with all causes of death attributed to hemorrhage. Six ischemic complications occurred in four patients (19.0%); ischemic stroke (n = 2], pulmonary embolism (n = 1), deep vein thrombosis (n = 1), liver ischemia (n = 1), and bowel ischemia (n = 1).

CONCLUSION

We report poor overall outcomes, a low rate of hemostatic effectiveness, and a high rate of ischemic complications and mortality in this retrospective analysis of oral FXa inhibitor reversal with andexanet alfa for extracranial bleeds. More rigorous epidemiological, and ideally randomized studies, are needed to determine the role of andexanet alfa for FXa inhibitor-associated bleeding for extracranial hemorrhages, where large variation in severity and presentation exists.

Fibrinogen Concentrate for the Treatment of Thrombolysis-Associated Hemorrhage in Adult Ischemic Stroke Patients

In patients with ischemic stroke who receive systemic recombinant tissue plasminogen activator (rt-PA), the risk of secondary hemorrhage is 1-7%. Fibrinogen supplementation with cryoprecipitate is recommended in patients with rt-PA-associated symptomatic hemorrhage. We examined whether fibrinogen concentrate can be used safely in this setting. A single-center retrospective case series was performed in patients who received fibrinogen concentrate for post-rt-PA hemorrhage between January-2012 and December-2017. The primary outcome was the incidence of in-hospital thromboembolic events and infusion reactions. Secondary outcomes included incidence of clinically significant ICH expansion within 24-hours and patient serum fibrinogen response to fibrinogen concentrate therapy. Thromboembolic events occurred in 3 (12.5%) of 24 patients included in the analysis. No patients experienced infusion-related reactions. Five of 22 patients with ICH experienced clinically significant hemorrhage expansion. Hypofibrinogenemia was corrected in 87.5%(7/8) of patients with baseline hypofibrinogenemia, with a median increase in serum fibrinogen 166 mg/dL. Median fibrinogen increase in patients without baseline hypofibrinogenemia was 18 mg/dL. Fibrinogen concentrate is a safe potential therapeutic option to restore fibrinogen levels in acute ischemic stroke patients with thrombolysis-associated hemorrhage.

Evaluation and optimization of prescribed concomitant antiplatelet and anticoagulation therapy centrally managed by an anticoagulation management service

Patients on long-term anticoagulation combined with antiplatelet therapy have an increased risk of bleeding compared to patients on anticoagulation alone. The aim of this study was to evaluate the appropriateness of antiplatelet therapy in patients who are on long-term warfarin therapy and are managed by Brigham and Women's Hospital Anticoagulation Management Service (BWH AMS). This was a single-center, prospective chart review of patients managed by BWH AMS who were on long-term warfarin therapy plus full-dose aspirin (325 mg), an oral P2Y₁₂ inhibitor (clopidogrel, prasugrel or ticagrelor) and/or acetylsalicylic acid/dipyridamole. Patients' cardiovascular (CV) benefit and risk of bleeding were assessed according to clinical guidelines. The major objective of the study was to determine the proportion of patients on dual antithrombotic therapy (DAT) or triple antithrombotic therapy (TAT) whose risk of bleeding outweighed CV benefit. Of the 2677 patients evaluated for inclusion,145 were on concomitant long-term warfarin therapy plus aspirin (325 mg), an oral P2Y₁₂ inhibitor and/or acetylsalicylic acid/dipyridamole. A total of 85 patients (58.6%) had no clear indication for DAT or TAT per guideline recommendations and were categorized as bleeding risk outweighing CV benefit. The remaining 60 patients (41.4%) had an appropriate indication for DAT or TAT per guidelines and were categorized as CV benefit outweighing bleeding risk. BWH AMS pharmacists made 33 (22.9%) recommendations to providers to discontinue or de-escalate antiplatelet therapy. Interventions were accepted for 10 (30.3%) patients. Pharmacist involvement in the management of patients' antithrombotic regimens can optimize guideline-directed medical therapy and mitigate the potential risk of bleeding.

Evaluation of Antifactor-Xa Heparin Assay and Activated Partial Thromboplastin Time Values in Patients on Therapeutic Continuous Infusion Unfractionated Heparin Therapy

Clinical uncertainty exists regarding which assay should be designated as the standard monitoring coagulation test for intravenous unfractionated heparin (UFH). Several studies have compared the use of activated partial thromboplastin time (aPTT) and antifactor-Xa (anti-Xa) and have come out with varying results. The correlation between these 2 tests varied, markedly from strong to weak. Some have demonstrated that monitoring with anti-Xa heparin assay leads to fewer dose adjustments, resulting in fewer laboratory tests, while others have not. In the current study, we evaluated the correlation between aPTT and anti-Xa values to guide clinical management of UFH, with the intention to develop a new correlation nomogram.

Development of Multidisciplinary Anticoagulation Management Guidelines for Patients Receiving Durable Mechanical Circulatory Support

Patients receiving durable mechanical circulatory support (MCS) require life-long anticoagulation with a vitamin K antagonist (VKA). Due to alternations in hemostasis, concomitant therapy with antiplatelet agents and critical illness, they are at increased risk of thromboembolic and bleeding complications compared with the general population managed on VKAs. To prevent thrombotic events, current guidelines recommend that patients with MCS receive long-term anticoagulation with a VKA to maintain a target international normalized ratio (INR) as specified by device manufacturers, but limited data exist regarding specific routine management of anticoagulation therapy and its potential complications. To optimize anticoagulation management and minimize risk in these patients, we have centralized anticoagulation management in a collaborative approach between the inpatient hemostatic and antithrombotic (HAT) stewardship service and between ambulatory anticoagulation management service (AMS) and the advanced heart disease team. Patients are followed by these three services beginning when the device is implanted and extending the duration that patients have the device. The teams include multiple clinicians from cardiac surgery, cardiology, hematology, pharmacy, nursing, case management, nutrition, and psychiatry, therefore, in order to standardize practice among clinicians without compromising patient centered decision making, we assembled an interdisciplinary team to create multiple treatment guidelines. In addition to a centralized and collaborative approach, our guidelines ensure seamless transitions of care between the inpatient and outpatient settings. We believe our approach has demontrated a positive improvement in the care of these challenging patients. In this article, we present our comprehensive centralized anticoagulation management approach for patients with left ventricular assist systems (LVAS).

Derivation and Validation of Age- and Body Mass Index-Adjusted Weight-Based Unfractionated Heparin Dosing

Unfractionated heparin dosing is unpredictable and subject to numerous pharmacokinetic changes including distribution and metabolic changes associated with obesity and age. Weight-based dosing is commonly used to better predict the dose for a patient when targeting a therapeutic range. A dosing equation that adjusts weight-based doses for age and body mass index may improve therapeutic dose prediction. We conducted a 2-phase observational study with a derivation and validation period to develop an equation to adjust weight-based unfractionated heparin for age and body mass index to target a therapeutic activated partial thromboplastin time of 60 to 80 seconds. The first phase retrospectively identified patients who acheived therapeutic anticoagulation and utilized linear regression to determine a predictive equation for weight-based dosing that adjusts for age and body mass index. The second phase prospectively identified patients in an observational manner and compared the dose of unfractionated heparin on which they became therapeutic against both the weight-based dose and the predicted dose adjusted for age and body mass index. The correlation between predictive age and body mass index adjusted dose and actual therapeutic dose was 0.703 compared to the correlation between the empiric weight-based dose and actual therapeutic dose which was 0.532 (P = .05). Age and body mass index adjusted weight-based dosing significantly improved therapeutic dose prediction for unfractionated heparin. Further study in a prospective, randomized trial is warranted for validation of this approach in a real world setting.

Betrixaban in the prevention of venous thromboembolism in medically ill patients

Despite significant advances in strategies and compliance with venous thromboembolism (VTE) prophylaxis, hospital-acquired VTE remains a leading cause of preventable deaths in acute medically ill patients. A majority of venous thromboembolic events occur posthospital discharge when risk factors persist and pharmacoprophylactic regimens have been completed. Until recently, there has been an unmet need for safe and effective extended-duration VTE prevention. Three major trials evaluated this concept, but excess bleeding outweighed the benefit of reduced thromboembolic events. Betrixaban is an oral direct factor Xa inhibitor recently approved for extended-duration VTE prophylaxis in acute medically ill patients at risk for thromboembolism based on results from the Phase III APEX study. This article reviews the pharmacology and supporting data for betrixaban.

Time in the Therapeutic Range for Assessing Anticoagulation Quality in Patients Receiving Continuous Unfractionated Heparin

Due to variable pharmacokinetic properties, therapeutic anticoagulation with continuous unfractionated heparin (UFH) requires ongoing laboratory monitoring, generally with activated partial thromboplastin time (aPTT). In the ambulatory setting, clinicians who manage warfarin therapy often use time in the therapeutic range (TTR) to estimate a percentage of time the international normalized ratio is therapeutic. We applied the TTR concept to aPTT monitoring for therapeutic UFH and used 2 methodologies for estimation: percentage of aPTT values in range (%aIR) and a modification of the Rosendaal method (mod-Rosendaal). This study included adult inpatients admitted between September 30, 2015, and September 30, 2016, at Brigham and Women’s Hospital. For each patient, all available aPTT values were extracted to calculate 2 individual TTRs according to each methodology. Comparison between methods was performed using Student t test, and correlation was assessed with simple linear regression. A total of 255 patients were included in this study. The major outcome of TTR estimation was significantly higher using mod-Rosendaal (43.7% [26.5%]) versus %aIR (37.7% [25.7%], P = .012) by a mean difference of 6% points (95% confidence interval: 1.3-10.7). Time in the therapeutic range estimated by mod-Rosendaal significantly correlated with those estimated by %aIR (r = 0.84, P < .001). Further studies should evaluate the correlation between TTR and clinical outcomes and establish a benchmark for quality therapeutic anticoagulation with continuous UFH.

Expanding anticoagulation management services to include direct oral anticoagulants

Despite the ease of use of direct oral anticoagulants (DOACs), these agents remain high risk medications and their clinical efficacy can be impacted by factors such as patient adherence, drug procurement barriers, bleeding leading to discontinuation, and prescribing that deviates from approved dosing regimens. Clinical monitoring of patients on DOACs should be performed by clinicians who specialize in anticoagulation and are familiar with the nuances of DOAC dosing, monitoring, and other components of anticoagulation management including peri-procedural management and care transitions. Although data for centralized warfarin management have consistently demonstrated improved clinical outcomes compared to traditional management by individual community providers, there are no published data addressing the impact of centralized management of DOACs on clinical outcomes or anticoagulation control. In addition, there is currently no consensus on how to incorporate patients on DOACs into this centralized model, despite recommendations for systematic follow-up by both the Anticoagulation Forum and the Institute for Safe Medication Practices. Based on the national recommendations and an identified institutional need, the Brigham and Women's Hospital Anticoagulation Management Service implemented a pilot program to expand services to include patients newly initiated on, or transitioned to, a DOAC. We describe our model for expansion of the AMS to include patients on DOACs.

Evaluation of Compliance with a Weight-based Nurse-driven Heparin Nomogram in a Tertiary Academic Medical Center

BACKGROUND

Recently, our institution adopted a weight-based nurse-driven heparin titration protocol that relies on nurses ordering laboratories, adjusting doses, and initiating boluses. Numerous institutions have implemented similar protocols with reported success.

METHODS

A single-center retrospective analysis was conducted at the Brigham and Women's Hospital in Boston, Massachusetts that included all patients who were initiated on the weight-based nurse-driven heparin nomogram during a 30-day period. Nomogram compliance was defined as the rate of correct titrations per nomogram encounter and further separated into laboratory, titration, or dosing compliance. Spearman's coefficient was utilized to determine the correlation between noncompliance and percentage of activated partial thromboplastin time (aPTT) values in range.

RESULTS

Overall, 211 patients were evaluated for inclusion, of which 95 patients were determined to meet criteria for evaluation. The total nomogram compliance rate was 84.6% ± 10.5%. Laboratory, titration, and dosing compliances were 77.6% ± 19.2%, 87.2% ± 14.5%, and 91.8% ± 10.6%, respectively. The percent of aPTT values in therapeutic range was 39.6% ± 24.6%. A moderate negative correlation between the percentage of aPTT values in range and the nomogram error rate was observed (r = -0.452, P < 0.001). This relationship was found to be driven by the rate of dosing error, which showed the strongest correlation with percentage of aPTT values out of range (r = -0.465, P = 0.001).

CONCLUSIONS

Implementation of a nurse-driven heparin titration nomogram relies on compliance with the prescribed protocol. Dosing compliance had the lowest error rate, whereas dosing noncompliance had the strongest impact on percentage of aPTT values in range.

Utilization of an Integrated Electronic Health Record in the Emergency Department to Increase Prospective Medication Order Review by Pharmacists

PURPOSE:

The objective of this study is to evaluate the impact of an integrated medical record system on prospective medication order verification by pharmacists in the emergency department (ED) of a level I trauma center.

METHODS:

This was a single-center retrospective analysis comparing medication orders verified by a pharmacist during a 7-day period in 2013 (phase I) versus 2015 (phase II). Outcome measures include the percentage of medication orders reviewed by a pharmacist prior to administration and time from order entry to each of the following: pharmacist review, medication procurement from an automated dispensing cabinet (ADC), and medication administration.

RESULTS:

In total, 5450 medication orders were included in the study. The percentage of medication orders reviewed by a pharmacist prior to administration increased from 51.8% to 94% in phase I versus phase II, respectively ( P < .001). Median time from order entry to pharmacist verification decreased from 13 to 4 minutes in phase I versus phase II, respectively ( P < .001). Time from order entry to ADC dispense increased from a median of 9 minutes in phase I to 15 minutes in phase II ( P < .001). Time from order entry to nursing administration increased from a median time of 15 minutes in phase I to 23 minutes in phase II ( P < .001).

CONCLUSION:

Implementation of prospective pharmacist order verification in the ED increased the percentage of medications reviewed by a pharmacist prior to administration and improved pharmacist efficiency in the medication verification process. This increase in pharmacist review was associated with a marginal increase in time to medication procurement and administration.

Description and Evaluation of the Implementation of a Weight-Based, Nurse-Driven Heparin Nomogram in a Tertiary Academic Medical Center

Weight-based, nurse-driven heparin nomograms are reported in the medical literature to improve the time it takes to reach a minimum threshold for anticoagulation without compromising patient safety in specific indications or patient populations. This is the first report in the literature of an institution-wide protocol implementation and evaluation of effectiveness with simultaneous transition to an electronic health record. The purpose of implementing this practice change at our institution was to standardize practice, improve time to reach therapeutic anticoagulation, and improve patient safety. We conducted a retrospective analysis utilizing a pre/postimplementation design to compare outcomes. The primary end point evaluated was the time to reach minimum threshold value for therapeutic anticoagulation. Additionally, we assessed the percentage of patients who reached minimum threshold therapeutic anticoagulation within 24 hours, the percentage of patients with a critically supratherapeutic activated partial thromboplastin time (aPTT) value (≥120 seconds) during therapy, and a description of heparin titration for the first 4 aPTT results with nomogram use. Overall time to therapeutic anticoagulation decreased from a mean 18.7 to 11.7 hours (hazard ratio [HR] 1.59; 95% confidence interval 1.22-2.08; P < .0005). Percentage of patients receiving therapeutic anticoagulation within 24 hours increased from 74.4 to 88.5 (odds ratio [OR 2.97, P = .002) and the percentage of patients with an aPTT ≥120 seconds remained constant at 49.9 versus 46.8 (OR 0.92, P = .73). This practice change reduced time to therapeutic anticoagulation without an increase in the proportion of patients with a critically supratherapeutic aPTT at our institution.

Treatment of heparin-induced thrombocytopenia before and after the implementation of a hemostatic and antithrombotic stewardship program

In October 2013, we implemented a hemostatic and antithrombotic (HAT) stewardship program with the primary focus of ensuring appropriate use of intravenous direct thrombin inhibitors (DTI) in patients with heparin-induced thrombocytopenia (HIT). We sought to compare the duration and cost of DTI therapy for the management of HIT before and after implementation of the HAT stewardship program. Following institutional review board approval, we conducted a single center, retrospective chart review of all patients with a suspected diagnosis of HIT as assessed by an anti-heparin-PF4 enzyme-linked immunosorbent assay 6 months pre-HAT and post-HAT implementation. Patients were excluded if they were initiated on a DTI at an outside hospital, had a prior episode of HIT, or received mechanical circulatory support. Clinical characteristics, including demographics, comorbidities, medications, laboratory values, clinical and safety outcomes, length of stay, and mortality, were collected. A total of 592 patients were included; 333 patients were evaluated pre-HAT, while 259 patients were evaluated post-HAT. The mean duration of DTI treatment was significantly decreased in the post-HAT cohort (6.64 vs 5.17 days, p = 0.01), primarily driven by decreased duration of use for patients with suspected HIT (4.07 vs 2.86 days, p = 0.01). The HAT Stewardship program demonstrated a total decrease in annual costs associated with the diagnosis and management of HIT of $248,500. Our results indicate that the implementation of the HAT stewardship program had a significant impact on reducing the duration and costs of DTI therapy and the costs of laboratory evaluations in the management of HIT at our institution.

Evaluation of Dose-Reduced Direct Oral Anticoagulant Therapy

BACKGROUND

Compared with vitamin K antagonists, direct-acting oral anticoagulants (DOACs) have fixed dosing, limited drug interactions, and do not require therapeutic drug level monitoring. Dose adjustments are recommended for moderate renal dysfunction, low body weight, and select drug interactions.

OBJECTIVES

The aim of our study is to determine if DOAC dose reductions were appropriate based on the manufacturer labeling recommendations for each agent. We also followed patients' treatment outcomes.

METHODS

We retrospectively reviewed patients administered a DOAC at a reduced dose between January 2011 and August 2014. The primary outcome was adherence to current manufacturer dose recommendations. The secondary outcome measures were the incidence of thromboembolic events or any bleeding episodes, regardless of severity, while on therapy.

RESULTS

Of 224 patients included in the analysis, 43.3% of patients fit criteria for a dose adjustment according to manufacturer recommendations. Only 3 of 28 (10.7%) patients treated with apixaban met 2 out of 3 clinical criteria required for a dose reduction per manufacturer recommendations. Only 54.7% of rivaroxaban-treated patients and 32.2% of dabigatran-treated patients had renal insufficiency requiring a dose reduction. Half of our patient population received aspirin therapy, with 6.3% of patients on triple antithrombotic therapy (dual antiplatelet agents plus an anticoagulant). A past medical history significant for bleeding was prevalent in patients treated with a reduced-dose DOAC (32.1%, 20.4%, and 25.4% of patients in the apixaban-, rivaroxaban-, and dabigatran-treated groups, respectively). Thromboembolic events occurred in 10.7%, 3.6%, and 5.1% of patients in the apixaban, rivaroxaban, and dabigatran groups, respectively. Frequency of bleeding complications, regardless of severity, was 17.9%, 18.2%, and 23.7% of patients in the apixaban, rivaroxaban, and dabigatran groups, respectively.

CONCLUSION

We found that dose-adjusted DOAC therapy was often prescribed in a dose that was lower than package insert recommendations.

Direct Thrombin Inhibitor for LVAD Thrombosis: A Closer Look

Available options for the treatment of advanced heart failure have expanded to include the use of mechanical circulatory assist devices to improve quality of life in those both eligible and ineligible for heart transplant. Although there have been significant advancements in device technologies, anticoagulation protocols, and multidisciplinary team management, bleeding and thrombosis are the most common adverse effects. Management strategies for pump thrombosis and their outcomes vary considerably among mechanical circulatory support centers and include intensification of antithrombotic therapy (medical) and device exchange (surgical). We describe a successful case of medical therapy for pump thrombosis with bivalirudin monotherapy.

Comparison of an IgG-Specific Enzyme-Linked Immunosorbent Assay Cutoff of 0.4 Versus 0.8 and 1.0 Optical Density Units for Heparin-Induced Thrombocytopenia

BACKGROUND

Previous studies have demonstrated optimized diagnostic accuracy in utilizing higher antiheparin-platelet factor 4 (PF4) enzyme-linked immunosorbent assay (ELISA) optical density (OD) thresholds for diagnosing heparin-induced thrombocytopenia (HIT). We describe the incidence of positive serotonin release assay (SRA) results, as well as performance characteristics, for antiheparin-PF4 ELISA thresholds ≥0.4, ≥0.8, and ≥1.0 OD units in the diagnosis of HIT at our institution.

METHODS

Following institutional review board approval, we conducted a single-center retrospective chart review on adult inpatients with a differential diagnosis of HIT evaluated by both antiheparin-PF4 ELISA and SRA from 2012 to 2014. The major endpoints were to assess incidence of positive SRA results, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy at antiheparin-PF4 ELISA values ≥0.4 OD units when compared to values ≥0.8 and ≥1.0 OD units. Clinical characteristics, including demographics, laboratory values, clinical and safety outcomes, length of stay, and mortality, were collected.

RESULTS

A total of 140 patients with 140 antiheparin-PF4 ELISA and SRA values were evaluated, of which 23 patients were SRA positive (16.4%) and 117 patients were SRA negative (83.6%). We identified a sensitivity of 91.3% versus 82.6% and 73.9%, specificity of 61.5% versus 87.2% and 91.5%, PPV of 31.8% versus 55.9% and 63.0%, NPV of 97.3% versus 96.2% and 94.7%, and accuracy of 66.4% versus 86.4% and 88.6% at antiheparin-PF4 ELISA thresholds ≥0.4, ≥0.8, and ≥1.0 OD units, respectively.

CONCLUSION

Our study suggests an increased antiheparin-PF4 ELISA threshold of 0.8 or 1.0 OD units enhances specificity, PPV, and accuracy while maintaining NPV with decreased sensitivity.

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.

Pharmacy Response to the Boston Marathon Bombings at a Tertiary Academic Medical Center

Objective: Effective crisis response requires multidisciplinary communication and rapid action. Our goals are to highlight the experience of a pharmacy department’s response to the 2013 Boston Marathon bombing, to discuss the role of the pharmacist in a crisis response, and to identify potential learning opportunities for a future mass casualty event. Case Summary: Our initial response targeted 3 general areas: staffing, supplies, and communication. Pharmacist and technician staffing was increased throughout the hospital, with a 6-fold increase of pharmacists to the emergency department (ED). To ensure adequate supplies were available, inventory on the ED automatic dispensing cabinets (ADC) was assessed for vaccines, antibiotics, and vasoactive medications. ED pharmacists prepared emergent intravenous medications in the ED while the sterile products room bolstered our supply of intravenous medications for patients in the ED and operating room. Overall, there was a 33% increase in the number of ADC transactions, with pharmacists representing 28% of all ADC transactions. To optimize communication, we formulated a comprehensive plan for the timely dissemination of information to the entire pharmacy staff. Discussion: A mass casualty event is a rare occasion, and it is vital for the pharmacy department to respond rapidly with little notification. Conclusion: The role of a pharmacist is unique and can most effectively triage drug information and medication distribution, especially during times of high demand and high stress.

Esomeprazole and aspirin fixed combination for the prevention of cardiovascular events

Low dose aspirin therapy plays a fundamental role in both the primary and secondary prevention of cardiovascular events. Although the evidence using low dose aspirin for secondary prevention is well-established, the decision to use aspirin for primary prevention is based on an evaluation of the patient’s risk of cardiovascular events compared to their risk of adverse events, such as bleeding. In addition to the risk of bleeding associated with long term aspirin administration, upper gastrointestinal side effects, such as dyspepsia often lead to discontinuation of therapy, which places patients at an increased risk for cardiovascular events. One option to mitigate adverse events and increase adherence is the addition of esomeprazole to the medication regimen. This review article provides an evaluation of the literature on the concomitant use of aspirin and esomeprazole available through February 2013. The efficacy, safety, tolerability, cost effectiveness, and patient quality of life of this regimen is discussed. A summary of the pharmacokinetic and pharmacodynamic interactions between aspirin and esomeprazole, as well as other commonly used cardiovascular medications are also reviewed. The addition of esomeprazole to low dose aspirin therapy in patients at high risk of developing gastric ulcers for the prevention of cardiovascular disease, significantly reduced their risk of ulcer development. Pharmacokinetic and pharmacodynamic studies suggested that esomeprazole did not affect the pharmacokinetic parameters or the antiplatelet effects of aspirin. Therefore, for those patients who are at a high risk of developing a gastrointestinal ulcer, the benefit of adding esomeprazole likely outweighs the risks of longer term proton pump inhibitor use, and the combination can be recommended. Administering the two agents separately may also be more economical. On the other hand, for those patients at lower risk of developing a gastrointestinal ulcer, both the additional risk and cost make the inclusion of a proton pump inhibitor unwarranted.

Impact of robotic antineoplastic preparation on safety, workflow, and costs

PURPOSE

Antineoplastic preparation presents unique safety concerns and consumes significant pharmacy staff time and costs. Robotic antineoplastic and adjuvant medication compounding may provide incremental safety and efficiency advantages compared with standard pharmacy practices.

METHODS

We conducted a direct observation trial in an academic medical center pharmacy to compare the effects of usual/manual antineoplastic and adjuvant drug preparation (baseline period) with robotic preparation (intervention period). The primary outcomes were serious medication errors and staff safety events with the potential for harm of patients and staff, respectively. Secondary outcomes included medication accuracy determined by gravimetric techniques, medication preparation time, and the costs of both ancillary materials used during drug preparation and personnel time.

RESULTS

Among 1,421 and 972 observed medication preparations, we found nine (0.7%) and seven (0.7%) serious medication errors (P = .8) and 73 (5.1%) and 28 (2.9%) staff safety events (P = .007) in the baseline and intervention periods, respectively. Drugs failed accuracy measurements in 12.5% (23 of 184) and 0.9% (one of 110) of preparations in the baseline and intervention periods, respectively (P < .001). Mean drug preparation time increased by 47% when using the robot (P = .009). Labor costs were similar in both study periods, although the ancillary material costs decreased by 56% in the intervention period (P < .001).

CONCLUSION

Although robotically prepared antineoplastic and adjuvant medications did not reduce serious medication errors, both staff safety and accuracy of medication preparation were improved significantly. Future studies are necessary to address the overall cost effectiveness of these robotic implementations.