Benchmark for time in therapeutic range in venous thromboembolism: a systematic review and meta-analysis

Warfarin Time in Therapeutic INR Range and Direct Oral Anticoagulant Adherence for Venous Thromboembolism Across the Spectrum of Weight and Body Mass Index: Findings from Veterans Health Administration

The evidence of direct oral anticoagulants (DOACs) usage for venous thromboembolism (VTE) in patients at extremes of body weight or mass index is limited. In such situations, warfarin may be more frequently used. We investigated warfarin time in the therapeutic international normalized ratio range (TTR) and DOAC adherence based on the calculated proportion of days covered (PDC) by pill coverage from a DOAC prescription in patients with VTE across all body sizes. Using data from the Veterans Health Administration (VA), we identified first-time patients with VTE between 2013 and 2018 treated with warfarin or DOACs. We analyzed 28,245 patients with warfarin TTR (N  =  10,167) or DOAC PDC(N  =  18,078). For warfarin-treated patients after index VTE, mean TTR was lower over shorter treatment durations (TTR 30 vs TTR 180 [mean  ±  SD]: 43.8% ± 33.5% vs 58.8% ± 23.5%). Mean TTR over 180 days after VTE was lowest for patients <60 kg (TTR 180 [mean  ±  SD]: <60kg: 49.3% ± 24.2% vs ≥60 to <100 kg: 57.8% ± 23.4%; P < .0001). For DOAC-treated patients over 180 days after index VTE, mean PDC was lowest for patients <60 kg (PDC 180 [mean  ±  SD]: < 60kg: 76.9% ± 33.2% vs ≥ 60 to <100 kg: 83.6% ± 27.7%; P < .0001).Most DOAC-treated patients attained sufficient adherence across the body size spectrum while warfarin-treated patients <60kg were at risk for low TTR.

Evaluation of a pharmacist-led drive-up anticoagulation clinic during the coronavirus 2019 pandemic

Background

The University of Kentucky HealthCare Anticoagulation Clinic at the Gill Heart and Vascular Institute in Lexington, Kentucky, designed and implemented a drive-up clinic for warfarin management with the goal to minimize person-to-person exposure during the coronavirus disease 2019 (COVID-19) pandemic.

Objective

The purpose of this study was to evaluate the effect on warfarin management in a pharmacist-led anticoagulation service when transitioned from an in-person clinic to a drive-up clinic during the COVID-19 pandemic.

Methods

This is a retrospective observational cohort study of 68 patients seen in the University of Kentucky HealthCare Anticoagulation Clinic on warfarin therapy for any indication. Patients were included if they had scheduled visits at least 3 times in the period 6 months before, during, and after the initiation of the drive-up clinic. The primary outcome is the difference in time in therapeutic range (TTR) before and during the drive-up clinic.

Results

The difference between the mean TTR in period 1 (69.1% ± 23.2%) and period 2 (69.6% ± 19.2%) was not statistically significant (P = 0.882). The mean TTR in period 3 (70.5% ± 20.8%) did not differ in statistical significance from either period 1 (P = 0.688) or period 2 (P = 0.746). Safety outcomes including reported bleeding events and emergency department visits or hospital admissions for bleeding or thrombotic events were consistently low across each period.

Conclusion

The results of this study illustrate that a drive-up clinic for warfarin management may be a reasonable alternative approach to providing care for outpatient anticoagulant management and may support nontraditional clinic models for long-term management of anticoagulation and other chronic disease states.

Efficacy and Safety Profile of Novel Oral Anticoagulants in the Treatment of Left Atrial Thrombosis: A Systematic Review and Meta-Analysis

Background

The presence of left atrial/left atrial appendage thrombosis is associated with a higher risk of thromboembolic events in patients with atrial fibrillation. The optimal antithrombotic strategy is not established to date.

Objective

Our aim was to compare the efficacy and safety profile of novel oral anticoagulants with warfarin in the treatment of left atrial/left atrial appendage thrombosis.

Methods

We conducted a systematic search in PubMed, Embase, Cochrane Library, ClinicalTrials.gov, and 3 Chinese databases for all randomized controlled trials and cohort studies (PROSPERO, CRD42021238952) from inception to 7 May 2021. Two authors independently performed the articles selection, data extraction, and quality assessment. The efficacy outcome was the resolution of left atrial/left atrial appendage thrombosis, and the safety outcomes were bleeding and stroke/transient ischemic attack.

Results

One randomized controlled trial and 5 cohort studies were included, with a total of 353 patients. Compared with warfarin, novel oral anticoagulants were associated with increased probability of left atrial/left atrial appendage thrombosis resolution (OR = 2.20; 95% CI, 1.35–3.60; I² = 0%). Compared with warfarin, novel oral anticoagulants had a similar risk of bleeding (OR = 0.91; 95% CI, 0.39–2.13; I² = 0%). There was no evidence of increased risk of stroke/transient ischemic attack (OR = 0.42; 95% CI, 0.12–1.45; I² = 0%).

Conclusions

Novel oral anticoagulants were more effective than warfarin in promoting the resolution of left atrial/left atrial appendage thrombosis, without increased risks of bleeding and stroke/transient ischemic attack. Our study provides valuable insight into clinical practice. Further well-designed randomized controlled trials are needed to fully evaluate the benefits and risks in these patients. PROSPERO Registration No.: CRD42021238952.

Comparison of Warfarin Initiation at 3 mg Versus 5 mg for Anticoagulation of Patients with Mechanical Mitral Valve Replacement Surgery: A Prospective Randomized Trial

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.

Evaluation of Anticoagulation Control among Patients Taking Warfarin in University of Gondar Hospital, Northwest Ethiopia

INTRODUCTION

Warfarin is a widely used oral anticoagulant in clinical practice. It has variable intraindividual and interindividual dose response and a narrow therapeutic index. Therefore, it requires frequent and regular international normalized ratio (INR) determination to maintain the INR within the therapeutic range. The study evaluated parameters of anticoagulation control among patients on warfarin.

METHODS

A cross-sectional study was conducted at University of Gondar hospital. A consecutive sampling method was used to recruit study subjects. The anticoagulation control was evaluated by determining the proportion of desired INRs and the proportion of time spent in the therapeutic range (TTR). Logistic regression analysis was used to identify associated factors with adequate TTR. A P value <0.05 was used to declare significant association.

RESULT

A total of 338 study subjects were included in the study. The mean age of patients was 48.8 (SD = 16.4) years. Atrial fibrillation was the commonest indication for warfarin therapy. One-third (33%) of study subjects achieved the desired INRs of 2.0-3.0, while about one-tenth (13%) of patients attained good INR control (TTR ≥ 65%). Multivariate logistic regression analysis revealed no significant association of sociodemographic and clinical characteristics with good TTR outcome.

CONCLUSION

The level of anticoagulation control with warfarin among study subjects was very low. The authors recommend to implement a validated warfarin-dose titration protocol and to establish anticoagulation clinics to mitigate the low anticoagulation level.

Adherence to rivaroxaban for the treatment of venous thromboembolism-Results from the FIRST registry

BACKGROUND

Medication nonadherence can result in poor clinical outcomes and significant costs to health care providers. When treating venous thromboembolism (VTE), subtherapeutic anticoagulation may contribute to complications such as recurrent VTE or postthrombotic syndrome.

OBJECTIVES

To describe the extent, reasons for, and predictors of nonadherence to rivaroxaban for the treatment of VTE in clinical practice in the United Kingdom reported by participants of the FIRST registry.

PATIENTS/METHODS

The FIRST registry was an observational, multicenter registry reporting on the use of rivaroxaban in routine clinical practice. FIRST registry participants completed an adherence screening questionnaire during their treatment and follow-up.

RESULTS

In total, 1028 participants completed 1660 questionnaires over 2 years. One hundred thirteen of 1028 (11%) reported nonadherence at 28 days (interquartile range, 21-45). Reasons given for nonadherence at 1 month were forgetfulness (8.6% vs 74.7%; P < .001), carelessness (2.7% vs 27.3%; P < .001) or a change in routine (7.4% vs 25.5%; P < .001) reported by adherent and nonadherent participants, respectively. Older age (10-year increments) was the strongest predictor of good adherence (adjusted odds ratio, 1.21; 95% confidence interval, 1.06-1.39; 1 = adherent).

CONCLUSIONS

Overall adherence to rivaroxaban was high, and most nonadherence was unintentional. Identification of those at risk of nonadherence may reduce the risk of VTE recurrence and long-term complications.

Safety and effectiveness of dabigatran in routine clinical practice: the RE-COVERY DVT/PE study

RE-COVERY DVT/PE is a two-phase, international, observational study of anticoagulant therapy in patients with deep vein thrombosis and/or pulmonary embolism (DVT/PE). The objective of the second phase was to compare the safety and effectiveness of dabigatran versus a vitamin K antagonist (VKA) over 1 year of follow-up. Primary safety and effectiveness outcomes were major or clinically relevant nonmajor bleeding events (MBE/CRNMBEs) and symptomatic recurrent venous thromboembolism (VTE) (including deaths related to recurrent VTE). To minimize bias due to unbalanced patient characteristics, only patients in an overlapping range of estimated propensity scores were included (analytic set), and propensity score weighting was applied to compare outcomes. Outcome analysis used an as-treated approach, censoring patients after they stopped or switched their initial anticoagulant. Overall, 3009 patients enrolled from 2016 to 2018 were eligible: 60% were diagnosed with DVT alone, 21% with PE alone, and 19% with DVT plus PE. The analytic set consisted of 2969 patients. The incidence rate in %/year (95% confidence interval [CI]) of MBE/CRNMBEs was 2.63 (1.79-3.74) with dabigatran versus 4.48 (3.23-6.06) with warfarin; hazard ratio 0.63 (95% CI 0.32-1.25). For symptomatic recurrent nonfatal or fatal VTE the incidence rate was 1.53 (0.91-2.42) with dabigatran versus 2.01 (1.21-3.14) with VKAs; hazard ratio 0.78 (95% CI 0.30-2.02). In conclusion, we found lower annualized rates of MBE/CRNMBEs with dabigatran than VKA, although the difference was not statistically significant. Annualized rates of symptomatic VTE or related mortality were similar with dabigatran and VKA. These observational results with 1 year of follow-up reflect those of the randomized clinical trials. Trial registration: ClinicalTrials.gov identifier NCT02596230, first registered November 4, 2015.

Design and Rationale of HiLo: A Pragmatic, Randomized Trial of Phosphate Management for Patients Receiving Maintenance Hemodialysis

RATIONALE & OBJECTIVE

Hyperphosphatemia is a risk factor for poor clinical outcomes in patients with kidney failure receiving maintenance dialysis. Opinion-based clinical practice guidelines recommend the use of phosphate binders and dietary phosphate restriction to lower serum phosphate levels toward the normal range in patients receiving maintenance dialysis, but the benefits of these approaches and the optimal serum phosphate target have not been tested in randomized trials. It is also unknown if aggressive treatment that achieves unnecessarily low serum phosphate levels worsens outcomes.

STUDY DESIGN

Multicenter, pragmatic, cluster-randomized clinical trial.

SETTING & PARTICIPANTS

HiLo will randomize 80-120 dialysis facilities operated by DaVita Inc and the University of Utah to enroll 4,400 patients undergoing 3-times-weekly, in-center hemodialysis.

INTERVENTION

Phosphate binder prescriptions and dietary recommendations to achieve the "Hi" serum phosphate target (≥6.5 mg/dL) or the "Lo" serum phosphate target (<5.5 mg/dL).

OUTCOMES

Primary outcome: Hierarchical composite outcome of all-cause mortality and all-cause hospitalization. Main secondary outcomes: Individual components of the primary outcome.

RESULTS

The trial is currently enrolling.

LIMITATIONS

HiLo will not adjudicate causes of hospitalizations or mortality and does not protocolize use of specific phosphate binder classes.

CONCLUSIONS

HiLo aims to address an important clinical question while more generally advancing methods for pragmatic clinical trials in nephrology by introducing multiple innovative features including stakeholder engagement in the study design, liberal eligibility criteria, use of electronic informed consent, engagement of dietitians to implement the interventions in real-world practice, leveraging electronic health records to eliminate dedicated study visits, remote monitoring of serum phosphate separation between trial arms, and use of a novel hierarchical composite outcome.

TRIAL REGISTRATION

Registered at ClinicalTrials.gov with study number NCT04095039.

Efficacy of rivaroxaban in prevention of post-thrombotic syndrome: a systematic review and meta-analysis

OBJECTIVE

Direct oral anticoagulants (DOACs) have been recommended for the treatment of deep vein thrombosis (DVT). However, the benefits are uncertain for the prevention of post-thrombotic syndrome (PTS). We performed a systematic review and meta-analysis of reported studies to assess the efficacy of DOACs vs vitamin K antagonists for the risk reduction of PTS in patients with DVT.

METHODS

We searched PubMed, Medline, the Cochrane Library, Embase, and the Web of Science for studies reporting on the development of PTS after acute DVT. The outcomes were the risk reduction of PTS, PTS severity, the presence of residual vein thrombosis, and the incidence of recurrent venous thromboembolic (VTE) events.

RESULTS

A total of 59,199 patients from six retrospective and two randomized controlled studies had received DOAC treatment and were followed up for the development of PTS. In all studies, rivaroxaban had been compared with initial low-molecular-weight heparin followed by warfarin. Of the 59,199 patients, 19,840 (33.5%) had received rivaroxaban and 39,377 (66.5%), warfarin. The rivaroxaban group had a significant reduction in PTS development compared with the warfarin group (odds ratio [OR], 0.52; 95% confidence interval [CI], 0.43-0.63; P < .001). Severe PTS was less common in the rivaroxaban group than in the warfarin group (3.7% vs 6.4%; OR, 0.55; 95% CI, 0.36-0.85; P = .024). Additionally, rivaroxaban was associated with a significant reduction in VTE recurrence (OR, 0.83; 95% CI, 0.59-1.18; P = .03) and low rates of residual vein thrombosis compared with warfarin (36.5% vs 51.8%; P = .037).

CONCLUSIONS

Rivaroxaban after acute DVT was associated with a reduced risk of PTS compared with warfarin. Patients treated with rivaroxaban more rarely developed severe PTS and recurrent VTE events compared with patients treated with warfarin.

Implementation and Evaluation of Virtual Anticoagulation Clinic Care to Provide Incessant Care During COVID-19 Times in an Indian Tertiary Care Teaching Hospital

Background: COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-II) has become a global pandemic disrupting public health services. Telemedicine has emerged as an important tool to deliver care during these situations. Patients receiving Vitamin K antagonists (VKA) require structured monitoring which has posed a challenge during this pandemic. We aimed to evaluate the impact of Virtual anticoagulation clinic (VAC), a Telehealth model on the quality of anticoagulation, adverse events, and patient satisfaction vis-a-vis standard Anticoagulation clinic (ACC) care.

Materials and methods: A bidirectional cohort study was conducted in the Department of Cardiology, JSS Hospital, Mysore. Two hundred and twenty-eight patients in the VAC and 274 patients in the ACC fulfilling inclusion criteria were the subjects of the study. Telehealth tools like WhatsApp and telephone were used. Time in therapeutic range (TTR), Percentage of International normalized ratio in range (PINRR), and adverse events were analyzed and compared between the VAC group and the ACC group, between pre-COVID and COVID ACC groups, and between the VAC group and the same pre-COVID cohort. Patient satisfaction was assessed by a questionnaire at the end of 8 months. Descriptive statistics were used for the patient characteristics and inferential statistics for the comparisons between pre-VAC and VAC care.

Results: The mean TTR was 75.4 ± 8.9% and 71.2 ± 13.4% in the VAC group and ACC group, respectively (p < 0.001). The mean PINRR was 66.7 ± 9.4% and 62.4 ± 10.9% in the VAC group and ACC group respectively, (p < 0.001). There was no significant difference in TTR between the VAC group and the same pre-COVID cohort. The TTR differential between the pre-COVID and COVID ACC groups was significant. In either group, no major adverse events were seen. The most common tools used for data exchange were WhatsApp (83%) and SMS (17%). Seventy-four percent of patients were extremely satisfied with the overall VAC care.

Conclusions: Virtual anticoagulation clinic, a telehealth model can be used as an alternative option to deliver uninterrupted anticoagulation care during pandemic times.

ETNA VTE Europe: A contemporary snapshot of patients treated with edoxaban in clinical practice across eight European countries

INTRODUCTION

Edoxaban has proven its efficacy and safety in the ENGAGE AF-TIMI 48 and HOKUSAI-VTE clinical trials. Clinical practice patients, however, may differ from those enolled in clinical trials. We aimed to compare patients from the HOKUSAI-VTE clinical trial with those treated in clinical practice.

MATERIALS AND METHODS

ETNA-VTE-Europe is a prospective, non-interventional post-authorisation safety study conducted in eight European countries.

RESULTS

A total of 2,879 patients presenting with acute symptomatic venous thromboembolism (VTE) were enrolled at 339 sites. Of the 2,680 patients with complete data, 23.6% reported prior VTE and 2.8% had a history of bleeding. Patients in ETNA-VTE were older (65vs.57 years), more likely to be female (46.5vs.39.8%) and had a higher prevalence of chronic venous insufficiency (11.1vs.1.6%) than those in the European cohort of the HOKUSAI-VTE trial (n=1,512). Bodyweight and creatinine clearance were substantially lower in clinical practice. Edoxaban dosing was adherent to label in 90% of patients, with higher (60 mg) and lower than recommended doses (30 mg) used in 6.6% and 3.3% of the patients, respectively. Heparin lead-in was used in 84.7% of the patients overall, and was more frequently used in patients with PE than patients with DVT only (91.3% vs. 80.1%; p<0.0001).

CONCLUSIONS

These data reinforce the largely appropriate use of edoxaban in routine clinical practice, where the study population differs from those in prior randomised controlled trials. CLINICALTRIALS.

GOV IDENTIFIER

NCT02943993.

Satisfaction of Patients with Nonvitamin K Anticoagulants Compared to Vitamin K Antagonists: a Systematic Review and Meta-analysis

OBJECTIVE

 To undertake a systematic review and meta-analysis to assess the satisfaction of patients receiving nonvitamin K anticoagulants (NOACs), compared with vitamin K antagonists (VKAs).

METHODS

 We searched CENTRAL, MEDLINE, Embase, and Clinicaltrials.gov for randomized controlled trials (RCTs) and observational studies. Two reviewers screened, extracted, and appraised data independently. We pooled data using a random-effects model. Outcome included treatment satisfaction, which was assessed by scores of Duke Anticoagulation Satisfaction Scale (DASS), Anticlot Treatment Scale (ACTS), Perception of Anticoagulant Treatment Questionnaire 2 (PACT-Q2), or Treatment Satisfaction Questionnaire for Medication version II (TSQM-VII) and their domains reported with 95% confidence intervals (95% CIs). We followed MOOSE and PRISMA guidelines.

RESULTS

 We included four RCTs and 16 observational studies, enrolling 18,684 participants overall. Compared with VKAs, treatment with NOACs improved the ACTS Burdens score by 4.21 points (95% CI: 2.99-5.43, I ² = 95%, combined n = 6,180), and ACTS Benefits by 0.49 points (95% CI: 0.18-0.81, I ² = 85%, combined n = 6,171). Switching from VKAs to NOACs improved the ACTS Burdens score by 5.33 points (95% CI: 3.53-7.14, combined n = 3,097). Compared with VKAs, treatment with NOACs improved the TSQM-VII Global Satisfaction score by 6.86 points (95% CI: 3.00-10.73, combined n = 5,535).

CONCLUSION

 In patients with nonvalvular atrial fibrillation or venous thromboembolism, NOAC treatment is associated with greater satisfaction compared with VKAs. The switch from VKAs to NOACs was associated with improved patients' satisfaction. These effects were largely due to a lower degree of treatment burden with NOAC treatment.

Health-related quality of life correlates with time in therapeutic range in children on anticoagulants with International Normalised Ratio self-monitoring

BACKGROUND

Managing oral anticoagulant therapy with vitamin K antagonists remains challenging in paediatric medicine.

AIMS

This study aimed to assess the correlation between time in therapeutic range and quality of life in children participating in a non-selective International Normalised Ratio self-monitoring and vitamin K antagonist education programme.

METHODS

Children aged from 2 to 18 years and receiving vitamin K antagonist therapy were eligible for this prospective multicentre study. Clinical and demographic data were collected. Health-related quality of life was assessed using the PedsQL™ 4.0 questionnaire. Correlations between quality of life scores and time in therapeutic range were measured.

RESULTS

A total of 121 children were included in the study (mean age 9.6±4.9 years). Cardiac conditions were the predominant indication for vitamin K antagonists. The mean time in therapeutic range was 0.78±0.15 overall, and 0.76±0.24 over the 3-month period before quality of life assessment. The mean total quality of life score was 76.2±18 in self reports, 71.4±22 in mother reports and 73.5±19 in father reports. The time in therapeutic range correlated with the total quality of life scores in self reports (r=0.22; P=0.04), mother reports (r=0.23; P=0.02) and father reports (r=0.28; P=0.02). The time in therapeutic range predominantly correlated with school functioning in self reports (r=0.38; P=0.002) and mother reports (r=0.40; P<0.001), and with physical functioning in father reports (r=0.28; P=0.03).

CONCLUSIONS

Time in therapeutic range correlated with quality of life in children participating in a non-selective International Normalised Ratio self-monitoring and vitamin K antagonist education programme. Regular assessment of quality of life in patient education programmes contributes towards understanding the concerns and needs of patients.

Telemedicine-Based Specialized Care Improves the Outcome of Anticoagulated Individuals with Venous Thromboembolism-Results from the thrombEVAL Study

Venous thromboembolism (VTE) is a life-threatening disease with risk of recurrence. Oral anticoagulation (OAC) with vitamin K antagonists (VKA) is effective to prevent thromboembolic recurrence. We aimed to investigate the quality of OAC of VTE patients in regular medical care (RMC) compared to a telemedicine-based coagulation service (CS). The thrombEVAL study (NCT01809015) is a prospective, multi-center study to investigate OAC treatment (recruitment: January 2011-March 2013). Patients were evaluated using clinical visits, computer-assisted personal interviews, self-reported data and laboratory measurements according to standard operating procedures. Overall, 360 patients with VTE from RMC and 254 from CS were included. Time in therapeutic range (TTR) was higher in CS compared to RMC (76.9% (interquartile range [IQR] 63.2-87.1%) vs. 69.5% (52.3-85.6%), p < 0.001). Crude rate of thromboembolic events (rate ratio [RR] 11.33 (95% confidence interval [CI] 1.85-465.26), p = 0.0015), clinically relevant bleeding (RR 6.80 (2.52-25.76), p < 0.001), hospitalizations (RR 2.54 (1.94-3.39), p < 0.001) and mortality under OAC (RR 5.89 (2.40-18.75), p < 0.001) were consistently higher in RMC compared with CS. Patients in RMC had higher risk for primary outcome (clinically relevant bleedings, thromboembolic events and mortality, hazard ratio [HR] 5.39 (95%CI 2.81-10.33), p < 0.0001), mortality (HR 5.54 (2.22-13.84), p = 0.00025), thromboembolic events (HR 6.41 (1.51-27.24), p = 0.012), clinically relevant bleeding (HR 5.31 (1.89-14.89), p = 0.0015) and hospitalization (HR 1.84 (1.34-2.55), p = 0.0002). Benefits of CS care were still observed after adjusting for comorbidities and TTR. In conclusion, anticoagulation quality and outcome of VTE patients undergoing VKA treatment was significantly better in CS than in RMC. Patients treated in CS had lower rates of adverse events, hospitalizations and lower mortality. CS was prognostically relevant, beyond providing advantages of improved international ratio (INR) monitoring.

The experience of Hamad General Hospital collaborative anticoagulation clinic in Qatar during the COVID-19 pandemic

Hamad General Hospital Anticoagulation Clinic is one of the largest collaborative-practice clinics of its type in Qatar. The patients being followed at this clinic are typically complex and vulnerable. During the coronavirus disease 2019 pandemic, measures were implemented at the clinic to minimize the exposure of patients and healthcare providers to the acute respiratory syndrome coronavirus-2 and to promote social distancing. These measures included extending INR-recall period, transitioning to direct oral anticoagulant drugs whenever feasible, home visits to elderly and immunocompromised patients for INR testing, establishing an anticoagulation hotline, and relocation of warfarin dispensing from the main pharmacy to the anticoagulation clinic. In addition, the clinic shifted its multidisciplinary team meetings onto an online platform using Microsoft Teams. Telehealth consultations were extensively utilized to closely follow up with the patients and ensure that anticoagulation efficacy and safety remained optimal. The aim of this paper is to share our experience and describe the measures adopted by the clinic as part of the Hamad Medical Corporation response to the emerging situation.

Effectiveness and safety of rivaroxaban versus warfarin in obese patients with acute venous thromboembolism: analysis of electronic health record data

There is limited data evaluating clinical outcomes of rivaroxaban versus warfarin in obese patients with venous thromboembolism (VTE). Our objective was to evaluate the effectiveness and safety of rivaroxaban versus warfarin in obese VTE patients. We performed a cohort analysis using Optum® De-Identified Electronic Health Record data from 11/1/2012 to 9/30/2018. Patients with a body mass index (BMI) ≥ 30 kg/m² admitted to the hospital, emergency department or observation unit for VTE, prescribed rivaroxaban or warfarin as their first oral anticoagulant (OAC) within 7-days and had ≥12-months of EHR activity prior were included. We excluded patients with OAC use at baseline or cancer. Patients were 1:1 matched (standard differences<0.10). Primary outcomes were recurrent VTE and major bleeding at 3-, 6- and 12-months using an intent-to-treat approach. Subanalyses of BMI 30.0-34.9, 35.0-39.9 and ≥ 40 kg/m² were performed. Risk was compared using Cox regression and reported as hazard ratios (HRs) with 95% confidence intervals (CI). We identified 6755 rivaroxaban and 6755 warfarin users with BMI ≥ 30 kg/m² and incident VTE. At 3-, 6- and 12-months, rivaroxaban was associated with a reduced hazard of recurrent VTE compared to warfarin (HR 0.61, 95%CI   0.51-0.72; HR 0.65, 95%CI  0.55-0.77; HR 0.63, 95%CI  0.54-0.74) with no difference in major bleeding (HR  0.99, 95%CI  0.68-1.44; HR 0.90, 95%CI  0.64-1.26; HR 1.00, 95%CI  0.73-1.36). No statistical difference was found across BMI categories for either recurrent VTE (p-interaction≥0.43) or major bleeding (p-interaction ≥ 0.58) at any time point. In obese VTE patients, prescription of rivaroxaban was associated with a significantly reduced risk of recurrent VTE versus warfarin, without impacting major bleeding. Our findings remained consistent across BMI classes.

First-Line Therapies for VTE Treatment and Secondary Prophylaxis in Patients With Cancer: A New Direction

Objective:

To review evidence behind anticoagulants in cancer-associated venous thromboembolism (VTE) with a focus on low-molecular-weight heparins (LMWH) and the role of direct oral anticoagulants (DOACs).

Data Sources:

PubMed was searched using terms “venous thromboembolism,” “cancer,” and “anticoagulation.” This search was restricted to clinical trials, meta-analyses, and subgroup analyses. Additional references were identified from reviewing literature citations.

Study Selection:

English-language prospective and retrospective studies assessing the efficacy and safety of LMWH and DOACs in patients with cancer.

Data Analysis:

Several trials were analyzed that compared anticoagulation therapies for prevention of recurrent VTE in patients with cancer. Many studies comparing LMWH and vitamin K antagonists (VKAs) found nonsignificant differences between therapies. A single study demonstrated that LMWHs are superior to VKAs. This evidence supporting LMWH for long-term VTE treatment in patients with cancer is based on comparison to VKA, but results are limited by methodological issues, and the benefit of LMWH may be driven by poor control. Subanalyses of DOAC trials suggest these are equally or more effective as VKA in cancer, but this conclusion is underpowered.

Conclusion:

DOACs have the potential to bypass many challenges with traditional therapy. After analyzing the evidence available, we conclude that after careful consideration of risks and benefits, use of DOACs for VTE treatment are a reasonable option in patients with cancer.

Rivaroxaban versus warfarin for treatment and prevention of recurrence of venous thromboembolism in African American patients: a retrospective cohort analysis

Background

African Americans are under-represented in trials evaluating oral anticoagulants for the treatment of acute venous thromboembolism (VTE). The aim of this study was to evaluate the effectiveness and safety of rivaroxaban versus warfarin for the treatment of VTE in African Americans.

Methods

We utilized Optum® De-Identified Electronic Health Record data from 11/1/2012–9/30/2018. We included African Americans experiencing an acute VTE during a hospital or emergency department visit, who received rivaroxaban or warfarin as their first oral anticoagulant within 7-days of the acute VTE event and had ≥1 provider visit in the prior 12-months. Differences in baseline characteristics between cohorts were adjusted using inverse probability-of-treatment weighting based on propensity scores (standard differences < 0.10 were achieved for all covariates). Our primary endpoint was the composite of recurrent VTE or major bleeding at 6-months. Three- and 12-month timepoints were also assessed. Secondary endpoints included recurrent VTE and major bleeding as individual endpoints. Cohort risk was compared using Cox regression and reported as hazard ratios (HRs) with 95% confidence intervals (CIs).

Results

We identified 2097 rivaroxaban and 2842 warfarin users with incident VTE. At 6-months, no significant differences in the composite endpoint (HR = 0.96, 95%CI = 0.75–1.24), recurrent VTE (HR = 1.02, 95%CI = 0.76–1.36) or major bleeding alone (HR = 0.93, 95%CI = 0.59–1.47) were observed between cohorts. Analysis at 3- and 12-months provided consistent findings for these endpoints.

Conclusions

In African Americans experiencing an acute VTE, no significant difference in the incidence of recurrent VTE or major bleeding was observed between patients receiving rivaroxaban or warfarin.

Extent of Late Gadolinium Enhancement Predicts Thromboembolic Events in Patients With Hypertrophic Cardiomyopathy

BACKGROUND

Thromboembolic complications such as ischemic stroke or peripheral arterial thromboembolism are known complications in hypertrophic cardiomyopathy (HCM). We sought to assess the clinical and cardiovascular magnetic resonance (CMR) characteristics of patients with HCM suffering from thromboembolic events and analyzed the predictors of these unfavorable outcomes.Methods and Results:The 115 HCM patients underwent late gadolinium enhanced (LGE) CMR and were included in the study. Follow-up was 5.6±3.6 years. The primary endpoint was the occurrence of thromboembolic events (ischemic stroke or peripheral arterial thromboembolism). It occurred in 17 (14.8%) patients (event group, EG), of whom 64.7% (11) were men. During follow-up, 10 (8.7%) patients died. Patients in the EG showed more comorbidities, such as heart failure (EG 41.2% vs. NEG (non-event group) 14.3%, P<0.01) and atrial fibrillation (AF: EG 70.6% vs. NEG 36.7%, P<0.01). Left atrial end-diastolic volume was significantly higher in the EG (EG 73±24 vs. NEG 50±33 mL/m², P<0.01). Both the presence and extent of LGE were enhanced in the EG (extent% EG 23±15% vs. NEG 8±9%, P<0.0001). No patient without LGE experienced a thromboembolic event. Multivariate analysis revealed AF and LGE extent as independent predictors.

CONCLUSIONS

LGE extent (>14.4%) is an independent predictor for thromboembolic complications in patients with HCM and might therefore be considered as an important risk marker. The risk for thromboembolic events is significantly elevated if accompanied by AF.

Ultrasound Aspects and Recanalization Rates in Patients with Lower-Limb Deep Venous Thrombosis Treated with Rivaroxaban

BACKGROUND

In this article, we report the ultrasound aspects and recanalization rates of patients with deep venous thrombosis (DVT) in the lower limbs treated with the rivaroxaban, focusing on the recanalization rate and the ultrasonographic aspects.

METHODS

This was a prospective and consecutive cohort study of patients admitted with DVT who were submitted to treatment with rivaroxaban for 6 months at the Division of Vascular and Endovascular Surgery, Hospital do Servidor Público Estadual, São Paulo, Brazil, between March 2016 and July 2018.

RESULTS

Fifty-one patients with DVT were admitted to the Vascular Surgery Department and received rivaroxaban for 6 months. The follow-up time was 360 days. Analyses were performed at 180 and 360 days. The rate of total venous recanalization at 360 days was 76.4% (39 patients). The incidence of partial venous recanalization was 23.5% (12 patients). At the first month, 11 patients (21.7%) continued with total occlusion of the vein, with 4 patients (6.5%) with no residual thrombi. However, at 6 months, only 2 patients (2.2%) continued with total occlusion of the vein, with 26 patients (47.8%) with no residual thrombi. At 12 months, there were 39 patients (76.4%) with no residual thrombi. Univariate and multivariate logistic regression identified the following factors related to total venous recanalization: the absence of popliteal vein reflux (odds ratio [OR], 0.386; P = 0.007), no residual thrombi (OR, 3.213; P = 0.008), femoropopliteal clot length at 1 month (OR, 3.021; P = 0.016), femoropopliteal clot length at 6 months (OR, 2.234; P = 0.008). The incidence of post-thrombotic syndrome (PTS) at 12 months was 8.3%.

CONCLUSIONS

In this study, patients who received oral rivaroxaban displayed satisfactory total vein recanalization rate after 6 months and 12 months. The factors associated with better total recanalization rates were the absence of popliteal vein reflux, the absence of residual thrombi in the veins, femoropopliteal clot length at 1 month (OR, 3.021; P = 0.016), and femoropopliteal clot length at 6 months (OR, 2.234; P = 0.008). Moreover, the incidence of PTS at 12 months was 8.3%.

Standardized warfarin monitoring decreases adverse drug reactions

Background

While warfarin is the most commonly prescribed medication to prevent thromboembolic disorders, the risk of adverse drug reactions (ADR) poses a serious concern. This prospective study evaluated how primary care providers (PCP) and cardiologists at our Institution managed patients treated with warfarin with the goal of decreasing the number of warfarin ADRs.

Methods

A multidisciplinary anticoagulation task force was established at our Institution in 2014 to standardize warfarin monitoring and management. Between 2013 and 2017, we analyzed patients who were prescribed warfarin by their PCP or cardiologist upon hospital discharge and in the ambulatory setting to determine the international normalized ratio (INR) within 5, 10, and 30 days after discharge, time in therapeutic range (TTR), number of severe warfarin ADRs, and total and average cost reduction of all severe warfarin ADRs to determine whether there was an organizational cost savings following the implementation of standardized warfarin care.

Results

The warfarin ADR rate significantly decreased over the 5-year period, from 3.8 to 0.98% (p < 0.0001). The proportion of warfarin prescriptions out of all anticoagulants significantly decreased, from 72.2 to 42.1% (p < 0.001). The proportion of individuals who received an INR at 5, 10, and 30 days after hospital discharge compared to the total number of patients prescribed warfarin significantly increased (p < 0.001). The total cost of severe warfarin ADRs decreased by 57.6% between 2013 and 2017.

Conclusions

This study serves as a model to reduce the number of severe warfarin ADRs by the following tactics: (1) educating PCPs and cardiologists about evidence-based guidelines for warfarin management, (2) increasing the use of our Institution’s electronic warfarin module, and (3) enhancing patient compliance with obtaining INR.

Cost of Healthcare Associated With Deep Vein Thrombosis in Patients Treated With Warfarin in Turkey: 2010-2013 Database Analysis of a Tertiary Care Center

OBJECTIVES

To evaluate the cost of healthcare with respect to the quality of anticoagulation in patients with deep vein thrombosis (DVT) treated with warfarin in daily practice via the database analysis of a tertiary care center in the period 2010 to 2013.

METHODS

Of 258 307 records in total, 42 582 unique patients with DVT and 32 012 patients with international normalized ratio (INR) measurements were included. Overall, 6720 unique patients with DVT diagnosis and one or more INR measurements were identified, and the records of 4377 out of 6720 unique patients were validated and included in the analysis data set. The cost analysis was based on direct medical costs from the payer's perspective. Cost items were related to healthcare resource utilization (inpatient and outpatient services) during the study period, which provided a basis for calculation of per-patient, outpatient, inpatient, and total direct medical costs.

RESULTS

Mean outpatient, inpatient, and total hospital admission costs were $578, $2195, and $2785, respectively, for patients with time in the therapeutic range of 70% or more, whereas the same costs were $571, $2163, and $3192, respectively, for patients with time in the therapeutic range of less than 70%.

CONCLUSIONS

Our findings for a retrospective cohort of patients with DVT undergoing warfarin therapy reveal that patients spent 70% or more, as opposed to less than 70%, of follow-up time within the therapeutic INR range and that outpatient care, as opposed to inpatient care, was associated with lower healthcare costs. Given the significant contribution that hospital stay makes to the cost burden of DVT, our findings also highlight the association between poor warfarin anticoagulant control and increased hospitalization costs.

Improving warfarin therapy through implementation of a hospital-based pharmacist managed clinic in Jamaica

Background

Pharmacist managed warfarin clinics can improve the anticoagulation status of non-valvular patients. The first of such services was implemented at the Cornwall Regional Hospital in Jamaica in 2013.

Objectives

To assess the anticoagulation control of patients on warfarin therapy over six months in the pharmacist managed warfarin clinic at Cornwall Regional Hospital.

Methods

Retrospective docket review for the period January 2014 to December 2016 was done to include data of patients attending routine clinic appointments for at least six months. Age, gender, date of visit, indication for warfarin therapy, warfarin dose and International Normalized Ratio readings were extracted. Percentage time spent in therapeutic range (TTR) was calculated by month for six months using the Rosendaal linear interpolation method. Patient anticoagulation status was categorized as poor (TTR<40%), moderate (TTR=40-64%) or good (TTR≥65%) and anticoagulation status at three months and six months was compared.

Results

For the period of assessment, 52 patients were identified; the median age was 58 years and 36 patients were males. Deep vein thrombosis was the main indication for therapy (22 of 52) and median warfarin weekly dose ranged was 15.0-130 mg. At time of recruitment most of the patients were outside the target INR range (43 of 52). Within one month, the median TTR attained was 31% [IQR 62-10]. This significantly improved by second month to 60% [IQR 82-23] (p=0.001). By month three, the proportion of patients in good, moderate and poor anticoagulant status was 19/51, 15/51 and 17/51 respectively, which at six months changed to 23/51, 12/51. 16/51 respectively; thus, although coagulation status improved from month one to three, there was no significant improvement from month three to month six (p=0.31).

Conclusions

The pharmacist managed warfarin clinic monitoring services were successful in attaining TTRs >40% and sustaining these values over six months. The services should therefore be encouraged.

Retrospective cohort study for evaluating the INR monitoring patterns in patients with deep vein thrombosis in daily practice: Analysis of 2010-2013 database of a tertiary care center

OBJECTIVE

To evaluate the international normalized ratio (INR) monitoring patterns in patients with deep vein thrombosis.

METHODS

Of 32,012 patients with ≥1 outpatient INR measurement and 42,582 patients with confirmed deep vein thrombosis diagnosis registered to our hospital between 1 January 2010 and 31 December 2013, 6720 records were identified to have both deep vein thrombosis and international normalized ratio measurement, and 4.377 out of 6.720 single patient records were determined to be statistically analyzable.

RESULTS

Median INR measurement frequency was 6.47 times/year and patients had INR levels of 2-3 in 34.3% of follow-up time. Having ≥70% vs. <70% of follow-up time within therapeutic range was associated with lower hospital admission frequency (9.7 vs. 10.3 times/year).

CONCLUSION

Our study revealed only one-third of the follow-up time to be spent within therapeutic INR, association of INR therapeutic range with lesser number of hospital admissions and INR monitoring frequency of 6.47 times/year despite lack of stable INR control in most of the deep vein thrombosis patients.

Patient-Reported Treatment Experience with Oral Rivaroxaban: Results from the Noninterventional XALIA Study of Deep-Vein Thrombosis

For venous thromboembolism (VTE) treatment, patient satisfaction was shown to improve with rivaroxaban versus standard anticoagulation in the phase III EINSTEIN DVT and EINSTEIN PE trials. This substudy of the prospective, noninterventional XALIA study of rivaroxaban for deep-vein thrombosis treatment assessed if this was also observed in routine clinical practice. Patients enrolled in XALIA who received rivaroxaban or standard anticoagulation treatment were eligible for inclusion in this substudy. Treatment decisions were at the physician's discretion. Patients completed the 17-item Anti-Clot Treatment Scale (ACTS, comprising a 12-item Burdens subscale, a 3-item Benefits subscale and one global item per subscale) during follow-up. The propensity score-matched set (PMS) was used for the main analysis; the adjusted safety analysis (ASAF) set was used for confirmatory purposes. Analyses by follow-up visit and subgroup, including age, sex, and previous VTE, were also conducted. The PMS-ACTS analysis included 458 rivaroxaban-treated and 434 standard anticoagulation-treated patients. Baseline demographic and clinical characteristics were generally similar across treatment arms. ACTS Burdens scores significantly improved with rivaroxaban versus standard anticoagulation (least-squares mean difference of 2.4 ± 0.4 points; p  < 0.0001); ACTS Benefits scores were numerically higher with rivaroxaban (least-squares mean difference of 0.2 ± 0.1 points; p  = 0.2). Similar findings occurred across follow-up visits and subgroups. Results were confirmed in the ASAF-ACTS analysis. Consistent with phase III analyses, rivaroxaban was associated with improved ACTS Burdens scores; ACTS Benefits scores numerically favored rivaroxaban, although without reaching statistical significance.

Postthrombotic Syndrome in Patients Treated With Rivaroxaban or Warfarin for Venous Thromboembolism

Postthrombotic syndrome (PTS) is a frequent complication of venous thromboembolism (VTE). Using MarketScan claims data from January 2012 to June 2015, we identified adults with a primary diagnosis code for VTE during a hospitalization/emergency department visit, ≥6 months of insurance coverage prior to the index event and newly started on rivaroxaban or warfarin within 30 days of the index VTE. Patients with <4-month follow-up postindex event or a claim for any anticoagulant during 6-month baseline period were excluded. Differences in baseline characteristics between rivaroxaban and warfarin users were adjusted for using inverse probability of treatment weights based on propensity scores. Patients were followed for the development of PTS starting 3 months after the index VTE. Cox regression was performed and reported as hazard ratios with 95% confidence intervals (CIs). In total, 10 463 rivaroxaban and 26 494 warfarin users were followed for a mean of 16 ± 9 (range, 4-39) months. Duration of anticoagulation was similar between cohorts (median = 6 months). Rivaroxaban was associated with a 23% (95% CI: 16-30) reduced hazard of PTS versus warfarin. Rivaroxaban was associated with a significant risk reduction in symptoms of PTS compared to warfarin in patients with VTE treated in routine practice.

Characteristics and quality of oral anticoagulation treatment in pediatric patients in the Netherlands based on the CAPS cohort

Essentials The knowledge of quality and safety of acenocoumarol and phenprocoumon use in children is limited. We used data from a multicenter retrospective follow-up study in children in the Netherlands. The quality of anticoagulation control in the first month of use was low, but improved thereafter. No thromboembolic events occurred, however bleeding events occurred in 1-3 out of 10 patients.

SUMMARY

Background The use of vitamin-K antagonists in pediatric patients is rare and information on the quality and safety of treatment with acenocoumarol and phenprocoumon is limited. Objectives To assess the quality, safety and effectiveness during the first year of acenocoumarol and phenprocoumon treatment in pediatric patients in the Netherlands. Methods The Children Anticoagulation and Pharmacogenetics Study (CAPS) was designed as a multicenter retrospective follow-up study. Patients who used acenocoumarol or phenprocoumon at an age of ≤ 18 years, were selected from four pediatric hospitals and one anticoagulation clinic in the Netherlands. The quality of treatment was assessed by calculating the percentage of time in therapeutic INR range (TTR) for the first month and for every 3 months of use during the first year of treatment. Effectiveness and safety were assessed by the number of thromboembolic and bleeding events. Results In total, 213 patients participated, of whom 187 (155 acenocoumarol; 32 phenprocoumon) were included in this analysis. The mean TTR was 47.0% and 51.4% in the first month of use for acenocoumarol and phenprocoumon, respectively. After the first 3 months the mean TTR for both VKAs was above 64%. In 14.6% (acenocoumarol) and 31.3% (phenprocoumon) of the patients a bleeding event occurred during the first year of treatment; no thromboembolic events were reported. Conclusions The quality of anticoagulation treatment was low during the first month of use and leaves room for improvement. After the first month it increased to an acceptable level. However, bleeding events occurred frequently during the first year.

Vitamin K antagonist therapy: changes in the treated populations and in management results in Italian anticoagulation clinics compared with those recorded 20 years ago

Vitamin K antagonists (VKA) are the most widely used anticoagulants in the world. An appropriate management of treated patients is crucial for their efficacy and safety. The prospective, observational, multicenter, inception-cohort FCSA-START Register, a branch of START Register (NCT02219984) included VKA-treated patients managed by centers of Italian Federation of anticoagulation clinics (AC). Baseline patient characteristics and data during treatment were analyzed and compared with those of ISCOAT study, performed by the Federation and published in 1996/7. 5707 naïve patients [53% males, mean age 73.0 years (28.1% >80 years)], 61.6% treated for atrial fibrillation (AF), and 28.0% for venous thromboembolism were included. During the 8906 patient-years (pt-yrs) of observation, 123 patients had major bleeding (MB) (1.38% pt-yrs; fatal: 0.11% pt-yrs), while non-major clinically relevant bleeds were 144 (1.62% pt-yrs). Bleeding was more frequent in elderly (≥70 years; p = 0.04), and during initial 3-month therapy (p = 0.02). Bleeding rate was 2.5% pt-yrs for temporally related INR results <3.0, increasing to 12.5% for INR ≥ 4.5. Thrombotic events were 47 (0.53% pt-yrs; 4 fatal 0.04% pt-yrs). Compared with ISCOAT-1996/7 results, patients older than 80 y are increased from 8 to 28% (p < 0.01), and those treated for AF are increased from 17 to 61%. The quality of anticoagulation control and incidence of MB are not different. However, thrombotic complications fell drastically from 3.5 to 0.53% pt-yrs (p < 0.01), with lower mortality (p = 0.01). VKA-treated patients monitored in Italian AC have good clinical results, with low bleeding and thrombotic complications rates. Important changes in the treated population and improvement in thrombotic complications are detected compared with the ISCOAT-1996/7 study.

The SAME-TT2R2 score predicts the quality of anticoagulation control in patients with acute VTE

The SAMe-TT2R2 score has recently been proposed to predict the quality of vitamin K antagonist (VKA) anticoagulation control in patients with atrial fibrillation. We aimed at investigating whether the score is effective also in patients with venous thromboembolism (VTE). Patients included in the START-Register because started VKA therapy for a recent VTE episode and with > 3 months follow-up were analyzed. The score was calculated using the baseline patient’s characteristics present in the electronic database of the registry, where all INR results were also available and analysed to calculate the time in therapeutic range (TTR). A total of 1308 patients (53.4 % female, median age 68 years) were analysed. During 998 patient-years followup, the median TTR was 63 %. The maximum score in the patients was 4, with 70 % of them having 0–1. INR controls within range (2.0–3.0) were significantly less prevalent in patients with score ≥ 2 vs 0–1 score (58.5 ± 20 % vs 61.5 ± 19 %, respectively, p = 0.046). Patients with score ≥ 2 vs 0–1 had a highly significant lower TTR during the first 3 months of therapy (53 ± 26 % and 61 ± 26 %, respectively; p=0.0001), difference mainly due to more time spent below 2.0 INR (38 ± 28 % vs 31.3 ± 26.7 %, respectively; p=0.0001). In conclusion, the study proved, for the first time, that the SAMe-TT2R2 score is useful to predict among VTE patients those who will have good (score 0–1) or less good (score ≥ 2) VKA anticoagulation control. The score can help decision-making in everyday clinical practice, especially when choosing between VKA and non-vitamin K antagonists direct anticoagulants.

Note: The review process for this paper was fully handled by Christian Weber, Editor in Chief.

Risk of myocardial infarction and death in patients with atrial fibrillation treated with dabigatran or vitamin K antagonists

The safety of dabigatran versus adjusted-dose vitamin K antagonist (VKA) treatment is the subject of debate. We evaluated the risk of myocardial infarction (MI) or mortality in patients with atrial fibrillation (AF) treated in clinical practice with dabigatran or a VKA. We performed a meta-analysis of observational studies that included an adjusted or matched analysis and reported MI, or death in AF patients treated with dabigatran or a VKA. Ten published analyses met the inclusion criteria. Of the 539,559 patients, 17,365 (3%) patients were on dabigatran 110 mg twice daily (bid), 150,948 (28%) were on dabigatran 150 mg bid, and 371,246 (69%) were on VKA. Adjusted risk for MI versus VKA was 0.71 (0.47–1.07; p=0.10) in patients starting oral anticoagulant (OAC) treatment with dabigatran 110 mg, 0.82 (0.71–0.96; p=0.01) in patients starting dabigatran 150 mg, 1.40 (1.04–1.88; p=0.03) in patients switching OAC treatment to dabigatran 110 mg, and 1.28 (0.88–1.87; p=0.19) in patients switching OAC treatment to dabigatran 150 mg, with statistical homogeneity in each subgroup. Risk of death was consistently lower in patients treated with dabigatran 110 mg (HR 0.79; 0.65–0.96; p=0.02) or 150 mg (HR 0.65; 0.57–0.73; p<0.00001) versus VKA. In conclusion, dabigatran use, as currently prescribed in routine practice for AF patients, was associated with a lower risk of MI in OAC-naïve patients treated with dabigatran 150 mg compared with VKA, and a higher risk of MI in patients switching from VKA to dabigatran 110 mg. Risk of death was lower in AF patients treated with either dose of dabigatran versus VKA.

Effectiveness and safety of rivaroxaban versus warfarin for treatment and prevention of recurrence of venous thromboembolism

The efficacy and safety or rivaroxaban versus enoxaparin/vitamin K antagonist for treatment and prevention recurrence of venous thromboembolism (VTE) was demonstrated in the randomised EINSTEIN trials. We assessed the effectiveness and safety of rivaroxaban versus warfarin in VTE patients managed in routine practice. Using US MarketScan claims from 1/2012–6/2015, we included adults with a primary diagnosis of deep vein thrombosis (DVT) or pulmonary embolism (PE) during a hospitalisation/emergency department visit, newly-initiated on rivaroxaban or warfarin within 30-days after the VTE and with ≥180-days of continuous medical/prescription benefits prior to the VTE (baseline). Patients with a claim for anticoagulation at baseline were excluded. Recurrent VTE, major bleeding, intracranial haemorrhage (ICH) and gastrointestinal bleeding (GIB) were assessed. Differences in baseline characteristics between cohorts were adjusted for using inverse probability of treatment weights based on propensity-scores. Patients had a maximum of 12-months period of follow-up post-VTE or until endpoint occurrence, switch/discontinuation of index anticoagulation, insurance disenrollment or end-of-follow-up. Cox regression was performed and reported as hazard ratios (HRs) with 95% confidence intervals (CIs). In total, 13,609 rivaroxaban and 32,244 warfarin users experiencing VTE were included. Rivaroxaban was associated with an 19% (95%CI=10–27%) reduction in recurrent VTE and a 21% (95%CI=4–35%) reduction in major bleeding hazard versus warfarin. Rivaroxaban was also associated with significantly decreased hazards of ICH (HR=0.40) and GIB (HR=0.72). Rivaroxaban appears to reduce patients’ hazard of both recurrent VTE and major bleeding in routine practice. These results appear consistent with EINSTEIN and post-marketing registry studies.

Supplementary Material to this article is available at www.thrombosis-online.com.

Retrospective comparison of low molecular weight heparin vs. warfarin vs. oral Xa inhibitors for the prevention of recurrent venous thromboembolism in oncology patients: The Re-CLOT study

Background There is increasing evidence indicating oral factor Xa inhibitors can be used for secondary prevention of venous thromboembolism. Studies are needed to compare oral factor Xa inhibitors, low molecular weight heparins, and warfarin in the oncology population. The purpose of this study is to evaluate the recurrent venous thromboembolism incidence in oncology patients utilizing oral Xa inhibitors, low molecular weight heparins, or warfarin. Methods Using retrospectively collected data, we compared the recurrent venous thromboembolism incidence in oncology patients taking rivaroxaban/apixaban, enoxaparin, or warfarin with at least three months of follow-up. Patients were included if they had an active cancer, venous thromboembolism, and taking warfarin, enoxaparin, or rivaroxaban/apixaban. The primary endpoint was the first episode of recurrent venous thromboembolism at three months. Secondary endpoints included recurrent venous thromboembolism after six months, major bleeding, and mortality. Results Of 127 venous thromboembolism patients, 48 received rivaroxaban or apixaban, 23 received enoxaparin, and 56 received warfarin. The three most common cancer diagnoses were lung (21%), colorectal (14%), and breast (14%). There was no difference in venous thromboembolism recurrence at three months between the rivaroxaban/apixaban (0%), warfarin (3.6%), and the enoxaparin cohorts (4.4%) (p = 0.8319). Major bleeding at three months was only seen in one patient in the enoxaparin arm (4.2%). Mortality at three months was 0%, 3.6%, and 17.4% in the rivaroxaban/apixaban, warfarin, and enoxaparin cohorts, respectively. Conclusion The results of this retrospective study suggest that oral factor Xa inhibitors are potential options for cancer patients with venous thromboembolism. However, randomized, controlled trials are needed to confirm these results.

Pharmacological management of pulmonary embolism

INTRODUCTION

Pulmonary embolism (PE) is a common and potentially severe manifestation of venous thromboembolism. Its management has relied on anticoagulation by vitamin K antagonists (VKA) for the past fifty years. Recently, new alternative drugs have been developed and dramatically modified both the treatment of acute PE and its secondary prevention. Areas covered: This review discusses the contemporary pharmacological treatment for PE, with a focus on anticoagulation options for non-high risk PE. In particular, the advent of direct oral anticoagulants (rivaroxaban, apixaban, edoxaban and dabigatran) and modalities for long-term prevention will be described. Options for anticoagulation for pregnancy-related PE are presented separately. Expert opinion: Direct oral anticoagulants represent the first-line therapy of non-high risk PE, with better risk-benefit ratios compared with VKA due to lower bleeding risks. In specific groups of patients, however, older generations of anticoagulants such as VKA or heparins still play an important role. Multiple alternatives are available for the secondary prevention of PE, with different efficacies in reducing thrombotic risk and bleeding safety profiles.

INR Stability, Clinical Importance, and Predictors in Patients With Atrial Fibrillation and Venous Thromboembolism Receiving Vitamin K Antagonists

Objective: Compare and contrast systematic reviews/meta-analyses assessing the time in the therapeutic range (TTR) for vitamin K antagonists (VKAs), clinical impact, and predictors. Data Sources: OVID MEDLINE search (1980-June 1, 2016) using the terms “vitamin K antagonist or warfarin” and “systematic review or meta-analysis” with backwards citation tracking from procured articles. Study Selection and Data Extraction: Search results were limited to systematic reviews assessing TTR with VKAs in patients with atrial fibrillation (AF) or venous thromboembolism (VTE). Data Synthesis: Six systematic reviews assessed TTR (4 in AF, 2 in VTE), and 3 of those assessed control at the time of a thrombotic or bleeding event (2 in AF, 1 in VTE). In patients on VKAs, greater TTR is correlated with fewer thromboembolic events and bleeding complications. VKA naïve patients have a harder time maintaining TTR than those with a previous knowledge of the likely therapeutic dose. Patients in the United States spend less TTR than those in other countries. Randomized clinical trials and anticoagulation clinics achieve greater TTR than those treated outside of these settings. The overall TTR has not improved from the first systematic reviews to the newest ones even though they were conducted 10 years apart and contained many new studies. Also, TTR in AF and VTE is similar. Conclusions: TTR is an important metric of VKA efficacy and safety and needs to be optimized. Many factors such as being VKA naïve can compromise TTR, and the use of anticoagulation clinics to optimize therapy is an important approach.

Factors Affecting the Quality of Anticoagulation With Vitamin K Antagonists in Venous Thromboembolism Patients

Introduction:

Treatment of venous thromboembolism (VTE) is classically based on oral vitamin K antagonists (VKAs). Due to the disadvantages and side effects of these drugs, monitoring the quality of anticoagulation by assessing time within therapeutic range (TTR) is recommended. Variables altering the TTR in patients with VTE are yet to be determined. The aim of this study was to analyze the quality of anticoagulation in patients with VTE treated with VKAs and to identify factors associated with poor-quality anticoagulation.

Methods:

A retrospective observational study was performed in a cohort of 94 patients diagnosed with VTE undergoing treatment with VKAs. The TTR at 6 months was analyzed by the Rosendaal method. Univariate and a multivariate logistic regression analyses were performed to unravel factors that increase risk of poor-quality anticoagulation.

Results:

The TTR at 6 months in this cohort was 60.5%; 54 patients had a TTR < 65%. In the univariate analysis, female sex, age ≥ 65 years, and renal impairment were significantly associated with poor-quality anticoagulation. However, in the multivariate logistic regression model, only renal impairment was independently associated with poor-quality anticoagulation (odds ratio = 3.31, 95% confidence interval [1.049, 10.486], p = .041).

Discussion:

The average quality of anticoagulation was 60.5%, and a high percentage of patients had a quality of anticoagulation below recommended levels. Study findings indicate that renal impairment is an independent risk factor for poor-quality anticoagulation in patients with VTE treated with VKAs.

Should oral anticoagulant therapy be continued during dental extraction? A meta-analysis

Background

Oral anticoagulation therapy is widely used to reduce the risks of thromboembolism. However, the therapy increases the risk of hemorrhage during the surgical procedures. The aim of this meta-analysis was to evaluate the bleeding risk of patients continuing or discontinuing oral anticoagulant therapy while undergoing dental extractions.

Methods

Six electronic databases, including PubMed, Embase, Cochrane library, Web of Science, China Biology Medicine disc (CBM), and China National Knowledge Infrastructure (CNKI), were searched in March, 2016. Relevant articles were screened by two independent reviewers under our inclusion criteria. Quality was evaluated using the Cochrane Collaboration risk of bias tool. Meta-analyses were conducted with fixed and random effects models as appropriate.

Results

Six studies (with a total of 591 patients) were included in our meta-analysis. Our results showed that there was no significant difference in the bleeding risk between patients continuing or discontinuing oral anticoagulant therapy while undergoing dental extractions (risk ratio, 1.31; 95 % CI, 0.79, 2.14; P > 0.05). There was also no significant difference in bleeding risk 1 day (risk ratio, 0.91; 95 % CI, 0.35, 2.37; P > 0.05) and 7 days (risk ratio, 1.47; 95 % CI, 0.83, 2.59; P > 0.05) after the dental extraction.

Conclusion

Under current studies and evidence, it appears that patients continuing oral anticoagulant therapy do not have an increased risk of bleeding after dental extractions compared to patients who discontinue oral anticoagulant therapy.

Prescribers' behavior following below- versus above-range international normalized ratio values in warfarin-treated deep vein thrombosis patients

Maintaining acceptable international normalized ratio (INR) control among deep vein thrombosis (DVT) patients taking warfarin is challenging. We evaluated prescribers' behavior to out-of-range INRs in DVT patients following initial INR stabilization. Following INR stabilization, a below-range INR was associated with fewer subsequent measurements and warfarin-dosing adjustments, and a longer time to re-achieve a therapeutic INR compared to an above-range INR.

Vitamin K antagonist use: evidence of the difficulty of achieving and maintaining target INR range and subsequent consequences

Vitamin K antagonists (VKAs) are effective oral anticoagulants that are titrated to a narrow therapeutic international normalized ratio (INR) range. We reviewed published literature assessing the impact of INR stability - getting into and staying in target INR range - on outcomes including thrombotic events, major bleeding, and treatment costs, as well as key factors that impact INR stability.

A time in therapeutic range (TTR) of ≥65 % is commonly accepted as the definition of INR stability. In the real-world setting, this is seldom achieved with standard-of-care management, thus increasing the patients’ risks of thrombotic or major bleeding events. There are many factors associated with poor INR control. Being treated in community settings, newly initiated on a VKA, younger in age, or nonadherent to therapy, as well as having polymorphisms of CYP2C9 or VKORC1, or multiple physical or mental co-morbid disease states have been associated with lower TTR. Clinical prediction tools are available, though they can only explain <10 % of the variance behind poor INR control.

Clinicians caring for patients who require anticoagulation are encouraged to intensify diligence in INR management when using VKAs and to consider appropriate use of newer anticoagulants as a therapeutic option.

Challenges in achieving a target international normalized ratio for deep vein thrombosis among HIV-infected patients with tuberculosis: a case series

Background

Tuberculosis (TB) and HIV are among the risk factors for deep vein thrombosis (DVT). There are several challenges in the management of DVT patients with TB-HIV co-infection including drug-drug interactions and non-adherence due to pill burden.

Methods

HIV infected patients starting treatment for TB were identified and followed up two weekly. Cases of DVT were diagnosed with Doppler ultrasound and patients were initiated on oral anticoagulation with warfarin and followed up with repeated INR measurements and warfarin dose adjustment.

Results

We describe 7 cases of TB and HIV-infected patients in Uganda diagnosed with DVT and started on anticoagulation therapy. Their median age was 30 (IQR: 27–39) years and 86 % were male. All patients had co-medication with cotrimoxazole, tenofovir, lamivudine and efavirenz and some were on fluconazole. The therapeutic range of the International Normalization Ratio (INR) was difficult to attain and unpredictable with some patients being under-anticoagulated and others over-anticoagulated. The mean Time in Therapeutic Range (TTR) for patients who had all scheduled INR measurements in the first 12 weeks was 33.3 %. Only one patient among those with all the scheduled INR measurements had achieved a therapeutic INR by 2 weeks. Four out of seven (57 %) of the patients had at least one INR above the therapeutic range which required treatment interruption. None of the patients had major bleeding.

Conclusion

We recommend more frequent monitoring and timely dose adjustment of the INR, as well as studies on alternative strategies for the treatment of DVT in TB-HIV co-infected patients.

Optimization of vitamin K antagonist drug dose finding by replacement of the international normalized ratio by a bidirectional factor: validation of a new algorithm

ESSENTIALS: We developed a new algorithm to optimize vitamin K antagonist dose finding. Validation was by comparing actual dosing to algorithm predictions. Predicted and actual dosing of well performing centers were highly associated. The method is promising and should be tested in a randomized trial.

SUMMARY

BACKGROUND

Oral vitamin K antagonists (VKAs) have a narrow therapeutic window and thus require frequent monitoring of its intensity by the international normalized ratio (INR). Improvement of VKA dosing defined as more time in therapeutic range (TTR) can reduce thrombotic disease and bleeding. Computerized decision support programs (CDSs) are used to optimize VKA dosing, but the effects are heterogeneous. CDSs significantly improve the proportion of time in the therapeutic INR range for initiation therapy but not the quality of anticoagulant management in an outpatient setting. One of the major problems of VKA dose finding is that the INR is a ratio and does not present linearity. We developed a new dose-finding algorithm, based on a novel bidirectional factor (BF). This BF is linear transformation of the nonlinear INR.

METHODS

We compared the outcomes of the new algorithm, called BF-N, with dose finding performed at three highly ranked Dutch anticoagulation centers, using both acenocoumarol and phenprocoumon.

RESULTS

The outcomes of the BF-N algorithm showed a linear correlation with VKA doses of the three centers (y = 1.001x, r(2) 0.999 for acenocoumarol and y = 0.999x, r(2) 0.999 for phenprocoumon), with a standard deviation of 3.83%. The rate of automated dosage proposals increased to 100%.

CONCLUSION

The BF-N algorithm performs well in real-life settings and increases the rate of automated dosage proposals. The algorithm can be easily built into existing CDSs. Experienced staff remains necessary for complicated situations. The new algorithm needs to be evaluated in a prospective trial.

Management of Venous Thromboembolism: Recent Advances in Oral Anticoagulation Therapy

OBJECTIVE

To review clinical data on direct oral anticoagulants (DOACs) used in the acute treatment of venous thromboembolism (VTE) as well as practical considerations when using these products.

DATA SOURCES

Searches of PubMed and Google Scholar for VTE, deep vein thrombosis, pulmonary embolism, and relevant drug international nonproprietary names were conducted. Additional online searches were conducted for prescribing information.

STUDY SELECTION AND DATA EXTRACTION

Relevant articles on dabigatran, rivaroxaban, apixaban, and edoxaban for the management of VTE compared with oral vitamin K antagonists (VKAs; published between 1966 and December 2015) were reviewed and summarized, together with information on dosing, pharmacokinetics/pharmacodynamics, and drug-drug interactions.

DATA SYNTHESIS

The DOACs have the potential to circumvent many of the disadvantages of VKAs. At a minimum, they greatly increase the available therapeutic options, thus providing a greater opportunity for clinicians to select a management option that best fits the needs of individual patients. Despite the significant advance that DOACs represent, they are not without risk and require careful consideration of a number of clinical issues to optimize safety and efficacy.

CONCLUSIONS

The emergence of DOACs for the management of thromboembolic disorders represents a paradigm shift from oral VKAs. The DOACs provide similar efficacy and improved safety in selected patients as compared with VKAs. Clinicians treating VTE need to be familiar with the intricacies involved in using these agents, including the appropriate dose selection for the relevant indication, avoidance of drug-drug and drug-disease interactions, and consideration of dose adjustments in specific clinical situations, such as organ dysfunction.

Percent Time in Range with Warfarin as a Performance Measure: How Long a Sampling Frame Is Needed?

BACKGROUND

Warfarin is received by millions of patients in the United States and elsewhere and will remain the most commonly used anticoagulant for the foreseeable future. Percent time in therapeutic range (TTR) with warfarin is increasingly used as a performance measure. However, stakeholders have expressed concern that TTR lags behind changes in performance. Work in a larger study focused on the impact of shortening the conventional measurement period for TTR.

METHODS

Some 124 sites within the Department of Veterans Affairs (VA) were examined during a seven-year period (fiscal years [FYs] 2008-2014 (April 1, 2007-September 30, 2014). The duration of time segments (2, 3, 4, 6 months) used to calculate TTR were varied, and these four durations were compared in terms of the number of patients retained per site, mean and median site TTR, and site performance rankings.

RESULTS

Data were obtained on 295,237 unique patients who received anticoagulation. As the calculation window shortened, patients with better control (that is, higher TTR) were selectively excluded from the measurement because their laboratory values were more widely spaced. Site mean TTR was highest when the most patients were included (6 months: 950 patients; TTR 65.2%) and lowest when the fewest patients were included (2 months: 567 patients; TTR 60.0%). However, the 3-, 4-, and 6-month segments achieved similar results, each of which included more than 800 patients per site, with mean TTR across a narrow range (64.9%-65.2%). Site rankings were less highly correlated between the 2-month period and longer periods (r = 0.7- 0.8) but were otherwise 0.95 or higher, with a nearly perfect correlation (0.985) between the 4- and 6-month periods.

CONCLUSIONS

When TTR is used to measure site-level performance, comparable results can be achieved using a 4- or a 6-month measurement period. On the basis of these results, the use of a 4-month period for future measurement efforts is recommended.

Early time courses of recurrent thromboembolism and bleeding during apixaban or enoxaparin/warfarin therapy. A sub-analysis of the AMPLIFY trial

Risks of recurrence and bleeding are highest during the first weeks of anticoagulant therapy for venous thromboembolism (VTE). We therefore examined the early time course of recurrence and major bleeding in a pre-specified sub-analysis of the AMPLIFY trial, a randomised, double-blind, six-month comparison of oral apixaban with conventional therapy (enoxaparin followed by warfarin) in 5,395 patients with symptomatic proximal deep-vein thrombosis or pulmonary embolism. Early events were of particular interest because apixaban was given without initial heparin treatment. The primary efficacy and safety outcomes were the incidences of the adjudicated composite of recurrent symptomatic VTE or death related to VTE, and of adjudicated major bleeding, respectively. This analysis reports on recurrence and bleeding after 7, 21, and 90 days of therapy, in addition to the previously reported end-of-study results. These were the times specified before statistical analysis. Recurrent VTE after 7, 21, and 90 days, and six months had occurred in 18 (0.7%), 29 (1.1%), 46 (1.8%), and 59 patients (2.3%), respectively, given apixaban, and in 23 (0.9%), 35 (1.3%), 58 (2.2%), and 71 patients (2.7%), respectively, given conventional therapy. Major bleeding had occurred during these time intervals in 3 (0.1%), 5 (0.2%), 11 (0.4%), and 15 patients (0.6%), respectively, who received apixaban, and in 16 (0.6%), 26 (1.0%), 38 (1.4%), and 49 patients (1.8%), respectively, given conventional therapy. Efficacy of apixaban was non-inferior at each time point, with no excess of early recurrences. The reduced bleeding risk associated with apixaban began early during the course of treatment.