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.

The CoVID-TE risk assessment model for venous thromboembolism in hospitalized patients with cancer and COVID-19.

BACKGROUND: Hospitalized patients with COVID-19 have increased risks of venous (VTE) and arterial thromboembolism (ATE). Active cancer diagnosis and treatment are well-known risk factors; however, a risk assessment model (RAM) for VTE in patients with both cancer and COVID-19 is lacking. OBJECTIVES: To assess the incidence of and risk factors for thrombosis in hospitalized patients with cancer and COVID-19. METHODS: Among patients with cancer in the COVID-19 and Cancer Consortium registry (CCC19) cohort study, we assessed the incidence of VTE and ATE within 90 days of COVID-19-associated hospitalization. A multivariable logistic regression model specifically for VTE was built using a priori determined clinical risk factors. A simplified RAM was derived and internally validated using bootstrap. RESULTS: From March 17, 2020 to November 30, 2020, 2804 hospitalized patients were analyzed. The incidence of VTE and ATE was 7.6% and 3.9%, respectively. The incidence of VTE, but not ATE, was higher in patients receiving recent anti-cancer therapy. A simplified RAM for VTE was derived and named CoVID-TE (Cancer subtype high to very-high risk by original Khorana score +1, VTE history +2, ICU admission +2, D-dimer elevation +1, recent systemic anti-cancer Therapy +1, and non-Hispanic Ethnicity +1). The RAM stratified patients into two cohorts (low-risk, 0-2 points, n = 1423 vs. high-risk, 3+ points, n = 1034) where VTE occurred in 4.1% low-risk and 11.3% high-risk patients (c statistic 0.67, 95% confidence interval 0.63-0.71). The RAM performed similarly well in subgroups of patients not on anticoagulant prior to admission and moderately ill patients not requiring direct ICU admission. CONCLUSIONS: Hospitalized patients with cancer and COVID-19 have elevated thrombotic risks. The CoVID-TE RAM for VTE prediction may help real-time data-driven decisions in this vulnerable population.

Cost-effectiveness of edoxaban versus dalteparin for the treatment of cancer-associated thrombosis.

Malignancy is a well-established risk factor for venous thromboembolism and while low-molecular-weight heparin therapy has been standard of care for cancer-associated thrombosis for many years, many patients find injection therapy burdensome. The direct oral anticoagulant edoxaban has been shown to be noninferior to dalteparin for the treatment of cancer-associated thrombosis. In a Markov simulation model, edoxaban with 6-month time horizon and a United States societal perspective with 2017 US dollars, edoxaban was the preferred strategy in the general cancer population (6-month cost $6061 with 0.34 quality adjusted life years) and in a subgroup of patients with gastrointestinal malignancy (6-month cost $7227 with 0.34 quality adjusted life years). The incremental cost effectiveness ratio of dalteparin compared to edoxaban was $1,873,535 in the general oncology population and $694,058 in the gastrointestinal malignancy population.

Andexanet Alfa (Andexxa) Formulary Review.

Andexanet alfa, a recombinant modified human "decoy" factor Xa (FXa) protein, is the first and only available antidote approved by the Food and Drug Administration to manage life-threatening or uncontrolled bleeding associated with the anti-Xa agents. It binds to direct and indirect anti-Xa oral anticoagulants with high specificity to reverse their inhibitory effects and restore the activity of FXa. Andexanet alfa is administered via two different dosing regimens, standard and high dose, based on the specific FXa inhibitor, dose, and time since the patient's last dose of FXa inhibitor. The approval for andexanet alfa is supported by data from two phase 3 studies (ANNEXA-A, ANNEXA-R) and preliminary data from the phase 3b/4 ANNEXA-4 trial. The first study found that andexanet alfa rapidly reduced anti-Xa activity by 92%-94% in healthy volunteers taking apixaban or rivaroxaban. The ANNEXA-4 study found that the median anti-Xa activity decreased by 89%-93% in patients with major bleeding taking apixaban or rivaroxaban. However, thrombotic events occurred in 12 of 67 patients (18%) during the 30-day follow-up in ANNEXA-4. Additionally, only 40% of patients had restarted anticoagulation and, in this group, the rate of thrombotic events was 12%. Four patients had a thrombotic event within 3 days after andexanet alfa treatment. The wholesale acquisition cost of the standard dose regimen is $24,750, and the high-dose regimen is $49,500. The estimated annual drug budget of treating 10-100 patients ranges from $248K to $495M. Effective October 1, 2018, Medicare will provide an add-on payment for andexanet alfa of up to $14,063 per qualifying case to Inpatient Prospective Payment System-participating acute care hospitals. In this formulary review for a health system's pharmacy and therapeutics committee, andexanet alfa clinical trials and medication package insert were summarized and, after consulting with clinical experts from our institutions, practical recommendations for use were generated to ensure appropriate and safe use of this agent.

Low-molecular weight heparin versus vitamin K antagonists for the treatment of cancer-associated thrombosis: A cost-effectiveness analysis.

INTRODUCTION: Cancer-associated venous thromboembolism (VTE) is primarily treated with low-molecular weight heparin (LMWH), a strategy based on studies showing it to be superior to the vitamin K antagonist (VKA) warfarin for preventing VTE recurrence. Subsequent analyses suggest that the magnitude of this benefit might be less than previously determined. Neither patient-focused measures of utility nor the costs of each strategy have been evaluated in the current treatment era. METHODS: This is a cost-effectiveness analysis of VKA and LMWH for the treatment of cancer-associated thrombosis through use of a microsimulation model of outcomes for competing anticoagulation management strategies from a 2014 United States societal perspective. RESULTS: LMWH therapy added 0.27 QALYs relative to VKA treatment with an ICER of $217,007. One-way sensitivity analysis evaluating the utility of LMWH revealed that VKA was always the preferred strategy at a willingness to pay (WTP) threshold of $100,000 per QALY. Limitations include that the model incorporates a low VKA time in therapeutic range (TTR) and that the TTR in some centers may be higher thereby increasing the cost-effectiveness of the VKA strategy. Utilities for anticoagulation strategies were not derived from cancer patients, and preference is known to vary depending on how anticoagulation method is integrated with cancer treatment. CONCLUSIONS: Our findings suggest that compared to LMWH, warfarin is a more cost-effective strategy to treat cancer-associated VTE. Although LMWH is associated with a modest increase in life expectancy, this increase comes at significant cost.

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.

Idarucizumab (Praxbind) Formulary Review.

Idarucizumab (Praxbind), a humanized monoclonal antibody fragment was granted accelerated approval from the Food and Drug Administration in October 2015 as the first agent to reverse the effects of a novel oral anticoagulant. The drug is indicated for dabigatran reversal in patients requiring emergency surgery/urgent procedures or with life-threatening or uncontrolled bleeding. In a randomized study with healthy volunteers, compared with placebo, idarucizumab reduced the clotting times for all tests assays (assessed pre-, end of-, and 24 hours after infusion), while the results for the placebo group remained unchanged. Another randomized clinical trial assessed the safety and efficacy of idarucizumab in patients with either overt bleeding or undergoing emergency surgery where hemostasis was required. This study is ongoing, but preliminary results showed reversal efficacy demonstrated a reasonable safety profile from the time of the infusion to 90 days after. The wholesale acquisition cost of two 2.5 g vials of idarucizumab is currently $3482.50. To treat 10 or 20 patients per year with a single 5 g dose is estimated to cost $34,825 and $69,650, respectively. In the clinical trial described above, approximately 20% of patients required a second dose, which would further increase the cost of use. In this formulary review for a health system's pharmacy and therapeutics committee, idarucizumab clinical trials and medication package insert were summarized and, after consulting with clinical experts from our institutions, practical recommendations for use were generated to ensure appropriate and safe use of this agent.

Implementation of a Hemostatic and Antithrombotic Stewardship program.

Hemostatic and antithrombotic (HAT) agents are high risk, high cost products. They require close monitoring and dose titration to adequately treat or prevent thrombosis while avoiding bleeding events. Incorporating the principles of inpatient anticoagulation management service into a stewardship program not only improves outcomes and decreases cost, but also improves transitions of care, exposes gaps in therapy management, and leads to the development of institution specific protocols and guidelines. We implemented a HAT Stewardship to provide real time clinical surveillance and management of these agents in an effort to optimize appropriate use, decrease serious adverse events, and minimize costs. The stewardship is staffed daily by an interdisciplinary team comprised of a pharmacist, hematology attending, and medical director. The stewardship focuses on (1) management of heparin-induced thrombocytopenia (HIT), (2) management of patients with Hemophilia A/B with inhibitors and acquired Factor VIII deficiency due to inhibitors, (3) oversight of anticoagulation in patients on extracorporeal membrane oxygenation and (4) assistance with anticoagulation management for patients with mechanical cardiac assist devices. Through implementation of this service, we have been able to demonstrate improved patient care and a positive economic impact exceeding the cost of this program by almost sixfold. Other centers should consider instituting a HAT Stewardship to maximize patient outcomes and minimize adverse events.