Meta-Analysis to Assess the Quality of International Normalized Ratio Control and Associated Outcomes in Venous Thromboembolism Patients

Outcomes of Patients with a Mechanical Heart Valve and Poor Anticoagulation Control on Warfarin

BACKGROUND

 Patients with a mechanical heart valve (MHV) require oral anticoagulation. Poor anticoagulation control is thought to be associated with adverse outcomes, but data are limited.

OBJECTIVE

 To assess the risks of clinical outcomes in patients with a MHV and poor anticoagulation control on warfarin.

METHODS

 We conducted a retrospective study of consecutive patients undergoing MHV implantation at a tertiary care center (2010-2019). Primary outcome was a composite of ischemic stroke, systemic embolism, or prosthetic valve thrombosis. Major bleeding and death were key secondary outcomes. We constructed multivariable regression models to assess the association between time in therapeutic range (TTR) on warfarin beyond 90 days after surgery with outcomes.

RESULTS

 We included 671 patients with a MHV (80.6% in aortic, 14.6% in mitral position; mean age 61 years, 30.3% female). Median follow-up was 4.9 years, mean TTR was 62.5% (14.5% TTR <40%, 24.6% TTR 40-60%, and 61.0% TTR >60%). Overall rates of the primary outcome, major bleeding, and death were 0.73, 1.41, and 1.44 per 100 patient-years. Corresponding rates for patients with TTR <40% were 1.31, 2.77, and 3.22 per 100 patient-years. In adjusted analyses, every 10% decrement in TTR was associated with a 31% increase in hazard for the primary outcome (hazard ratio [HR]: 1.31, 95% confidence interval [CI]: 1.13-1.52), 34% increase in major bleeding (HR: 1.34, 95% CI: 1.17-1.52), and 32% increase in death (HR: 1.32, 95% CI: 1.11-1.57).

CONCLUSION

 In contemporary patients with a MHV, poor anticoagulation control on warfarin was associated with increased risks of thrombotic events, bleeding, and death.

Heterogeneous distributions in clinical events preceding anticoagulant treatment nonpersistence in patients with venous thromboembolism stratified by active cancer: A nationwide cohort study

BACKGROUND

Nonpersistence in anticoagulation therapy is common and associated with undesirable clinical outcomes in patients with venous thromboembolism (VTE).

METHODS

We investigated preceding clinical events of treatment nonpersistence (e.g., switching, discontinuing, or restarting) in VTE patients with and without active cancer using Korean claims database.

RESULTS

Clinically significant events including thromboembolic events, hepatic function change and surgery preceded treatment nonpersistence, but heterogeneous distributions of clinical events were observed in the presence of active cancer. Patients with active cancer had a low rate of clinical events preceding treatment nonpersistence, and new active cancer diagnosis in the nonactive cancer group was most common before the switch to parenteral anticoagulants from warfarin or non-vitamin K antagonist oral anticoagulants (NOACs).

CONCLUSION

These findings suggest that clinically significant events can precede treatment nonpersistence and largely paralleled current guidelines for patients with VTE, whereas heterogeneous distributions of clinical events were observed in the presence of active cancer.

Recurrent thromboembolism, bleeding, and mortality in Asian patients with venous thromboembolism receiving different oral anticoagulants: A nationwide analysis

Venous thromboembolism (VTE) is associated with a high risk of morbidity and mortality. However, data on the association between oral anticoagulants and the hazards of VTE complications in Taiwanese patients with VTE is limited. This study aimed to compare the hazards of recurrent VTE, bleeding, and mortality between patients with VTE receiving rivaroxaban, a non-vitamin K antagonist oral anticoagulant (NOAC), and those receiving heparin or low-molecular-weight heparin (LMWH) followed by warfarin. Patients with VTE treated with rivaroxaban, or heparin or LMWH followed by warfarin were enrolled from 2 million random samples from Taiwan's National Health Insurance database between 2013 and 2016. Hazards of recurrent VTE (deep vein thrombosis and pulmonary embolism), major bleeding, and mortality in rivaroxaban and warfarin users were investigated. Survival analyses were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Users of rivaroxaban (183) and warfarin (456) were included in the study. Patients receiving rivaroxaban did not have significantly lower hazards of developing recurrent VTE (HR, 0.72 [CI, 0.37-1.37], P = .31) and mortality (HR, 0.86 [CI, 0.49-1.50], P = .59) than those receiving heparin or LMWH followed by warfarin. In addition, the hazard ratio of major bleeding was not significantly different between the 2 regimens (HR, 1.80 [CI, 0.39-8.29], P = .45). Rivaroxaban was not associated with lower risks of recurrent VTE and mortality and higher hazards of major bleeding than heparin or LMWH followed by warfarin in Taiwanese patients with VTE. Clinicians may tailor oral anticoagulants for VTE patients according to the patient's characteristics, cost-effectiveness and healthcare system policy.

The Effect of Switching From Warfarin to Novel Oral Anticoagulants on Patients’ Satisfaction and the Travel Burden in a Rural Setting

Introduction: New oral anticoagulants (NOACs) have shown comparable efficacy to warfarin in the treatment of patients with venous thromboembolism (VTE), stroke and atrial fibrillation (AF). Various studies on quality-of-life improvement in rural patients following the switch from vitamin K antagonists (VKAs) to NOACs have produced inconclusive results. The aim of the study is to assess the impact of switching from warfarin to NOACs on remotely living patients’ quality of life and the burden of travel.

Methods: A questionnaire was provided to the patient by their pharmacists. The questionnaire assessed their travel burden and their level of satisfaction with their treatment.

Results: The switch from warfarin to NOACs reduced the burden of travel in 75% of patients. A total of 66% of patients were hesitant about the efficacy of their warfarin treatment. The inconvenience caused due to international normalized ratio (INR) monitoring was reduced in 83% of patients; 70% and 72% of patients strongly agreed that NOACs improved their adherence and treatment satisfaction, respectively. The average number of patients’ travels for INR testing for warfarin monitoring was 7.27 trips/year. The average number of trips made by the patient to obtain their NOACs and warfarin scripts was 2.1 and 4.81 trips/year, respectively.

Conclusion: The switch from warfarin, a VKA, to NOACs in patients who live in remote areas without medical services improved their quality of life, decreased their travel burden, and increased their treatment satisfaction and adherence. Switching to NOACs reduced the number of trips travelled by patients to obtain their anticoagulation scripts and/or to adjust their doses.

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.

Dry Needling and Antithrombotic Drugs

Many clinicians increasingly use dry needling in clinical practice. However, whether patients' intake of antithrombotic drugs should be considered as a contraindication for dry needling has not been investigated to date. As far as we know, there are no publications in analyzing the intake of antiplatelet or anticoagulant agents in the context of dry needling techniques. A thorough analysis of existing medications and how they may impact various needling approaches may contribute to improved evidence-informed clinical practice. The primary purpose of this paper is to review the current knowledge of antithrombotic therapy in the context of dry needling. In addition, reviewing guidelines of other needling approaches, such as electromyography, acupuncture, botulinum toxin infiltration, and neck ultrasound-guided fine-needle aspiration biopsy, may provide specific insights relevant for dry needling. Based on published data, taking antithrombotic medication should not be considered an absolute contraindication for dry needling techniques. As long as specific dry needling and individual risks are properly considered, it does not change the risk and safety profile of dry needling. Under specific circumstances, the use of ultrasound guidance is recommended when available.

[Risk of post-thrombotic syndrome following direct oral anticoagulant intake: a systematic review and meta-analysis]

OBJECTIVE

To perform a systematic review and meta-analysis of data devoted to the risk of post-thrombotic syndrome (PTS) following direct oral anticoagulant (DOAC) intake.

MATERIAL AND METHODS

A systematic review and meta-analysis of trials available in the PubMed database were performed in March 2021. Analysis included the reports with known Villalta score for PTS in patients receiving DOACs or alternative anticoagulation. We analyzed the incidence and risk of any form of PTS.

RESULTS

We found 10 comparative studies comprising 3161 patients. Incidence of PTS under DOAC therapy was 30.8% (95% confidence interval (CI) 22.2-39.3%), severe PTS - 2.2% (95% CI 1.0-3.4%). DOACs were associated with significantly less risk of any form of PTS (odds ratio (OR) 0.57; 95% CI 0.48-0.68; p<0.001) and severe PTS (OR 0.56; 95% CI 0.36-0.87; p=0.010) compared to vitamin K antagonists. Among various DOACs, specified data were available only for rivaroxaban (OR 0.54, 95% CI 0.42-0.71, p<0.001 for any PTS; OR 0.49, 95% CI 0.27-0.89, p=0.019 for severe PTS). The use of flavonoids in adjunction to rivaroxaban was associated with additional risk reduction for PTS (OR 0.14; 95% CI 0.06-0.31; p<0.001).

CONCLUSION

Moderate quality evidence suggests that DOACs are associated with significant less risk of any PTS and severe PTS compared to VKA in patients with deep vein thrombosis. Among all DOACs, only rivaroxaban has clear data confirming PTS risk reduction. The use of flavonoids in adjunction to rivaroxaban can further improve treatment outcomes.

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.

Therapeutic quality control in a regional thrombosis center: The effect of changing the target intensity of anticoagulation with vitamin K antagonists

BACKGROUND

The target ranges (TR) for anticoagulation with vitamin K antagonists (VKA) in the Netherlands were changed in 2016 from INR 2.0-3.5 ('low intensity') and INR 2.5-4.0 ('high intensity') to INR 2.0-3.0 and INR 2.5-3.5, respectively.

AIM

To assess the effect of the TR change on therapeutic quality control (TQC) in a Dutch regional thrombosis center taking care of approximately 3600-5500 patients annually.

METHODS

TQC of chronically treated patients was assessed as the average time in therapeutic range (TTR). Evaluations were performed for non-self-management (NSM), as well as self-management patients. INR percentiles were assessed from all INR determinations in all patients, i.e. including those of induction episodes and patients treated for a short-term.

RESULTS

The number of NSM patients treated chronically decreased gradually, while their average age increased, with a marginal but significant gradual increase in bleeding complications. In the period 2011-2015, i.e. before the TR change, there was a gradual increase of the TTR in NSM patients from 77.5% to 88.9% (low intensity) and from 75.3% to 84.1% (high intensity). In the same period, the median INR of all patients in the low and high intensity ranges decreased from 2.9 to 2.7, and from 3.3 to 3.2, respectively. The TTR in self-management patients remained virtually constant. After TR changes from 2016 on, the TTR of all NSM patients in the low and high intensity groups decreased to 77% and 70%, respectively, and median INRs decreased to 2.6 and 3.0, respectively.

CONCLUSIONS

Introduction of internationally harmonized target ranges in 2016 resulted in further lowering of median INR values in both target ranges. As expected, TTR was reduced slightly. These findings, together with a slight increase in average age and concomitant bleeding complications, suggest that the patients on long-term VKA treatment will require intensified monitoring and treatment.

The efficacy and safety of Hirudin plus Aspirin versus Warfarin in the secondary prevention of Cardioembolic Stroke due to Nonvalvular Atrial Fibrillation: A multicenter prospective cohort study

Background: To investigate the efficacy and safety of hirudin plus aspirin therapy compared with warfarin in the secondary prevention of cardioembolic stroke due to nonvalvular atrial fibrillation (NVAF). Methods: Patients with cardioembolic stroke due to NVAF were prospectively enrolled from 18 collaborating hospitals from Dec 2011 to June 2015. Fourteen days after stroke onset, eligible patients were assigned to the hirudin plus aspirin group (natural hirudin prescribed as the traditional Chinese medicine Maixuekang capsule, 0.75 g, three times daily, combined with aspirin 100 mg, once daily) or the warfarin group (dose-adjusted warfarin targeting international normalized ratio (INR) 2-3, with an initial daily dose of 1.25 mg). Patients were followed up at 1, 2, 3, 6, 9, and 12 months after stroke onset. Time in therapeutic range (TTR) was calculated according to Rosendaal methodology to evaluate the quality of INR management in the warfarin group. The primary efficacy endpoint was the recurrence of stroke within 12 months after stroke onset. Safety was assessed as the occurrence of the composite event "intracranial hemorrhage and other bleeding events, death, and other serious adverse events". The Cox proportional hazard model and Kaplan-Meier curve were used to analyze the efficacy and safety events. Results: A total of 221 patients entered final analysis with 112 patients in the hirudin plus aspirin group and 109 in the warfarin group. Over the whole duration of our study, TTR for patients taking warfarin was 66.5 % ± 21.5%. A significant difference was not observed in the recurrence of stroke between the two groups (3.57% vs. 2.75%; P = 0.728). The occurrence of safety events was significantly lower in the hirudin plus aspirin group (2.68% vs.10.09%; P = 0.024). The risk for efficacy event was similar between the two groups (hazard ratio (HR), 1.30; 95% confidence interval (CI), 0.29-5.80). The safety risk was significantly lower in the hirudin plus aspirin group (HR, 0.27; 95% CI, 0.07-0.95). Kaplan-Meier analysis revealed significant difference in the temporal distribution in safety events (P = 0.023) but not in stroke recurrence (P = 0.726). Conclusion: Significant difference in efficacy was not detected between warfarin group and hirudin plus aspirin group. Compared with warfarin, hirudin plus aspirin therapy had lower safety risk in the secondary prevention of cardioembolic stroke due to NVAF.

Rivaroxaban Versus Warfarin for Management of Obese African Americans With Non-Valvular Atrial Fibrillation or Venous Thromboembolism: A Retrospective Cohort Analysis

African Americans (AAs) and obese individuals have increased thrombotic risk. This study evaluated the effectiveness and safety of rivaroxaban versus warfarin in obese, AAs with nonvalvular atrial fibrillation (NVAF) or venous thromboembolism (VTE). Optum® De-Identified Electronic Health Record (EHR) data was used to perform separate propensity-score matched analyses of adult, oral anticoagulant (OAC)-naïve AAs with NVAF or acute VTE, respectively; who had a body mass index≥30kg/m² and ≥12-months EHR activity with ≥1-encounter before OAC initiation. Cox regression was performed and reported as hazard ratios (HRs) with 95% confidence intervals (CIs). For the NVAF analysis, 1,969 rivaroxaban- and 1,969 warfarin-users were matched. Rivaroxaban was not associated with a difference in stroke/systemic embolism versus warfarin (HR = 0.88, 95%CI = 0.60-1.28), but less major bleeding (HR = 0.68, 95%CI = 0.50-0.94) was observed. Among 683 rivaroxaban-users with VTE, 1:1 matched to warfarin-users, rivaroxaban did not alter recurrent VTE (HR = 1.36, 95%CI = 0.79-2.34) or major bleeding (HR = 0.80, 95%CI = 0.37-1.71) risk versus warfarin at 6-months (similar findings observed at 3- and 12-months). Rivaroxaban appeared to be associated with similar thrombotic, and similar or lower major bleeding risk versus warfarin in these obese, AA cohorts.

Evaluation of the SAMe-TT2R2 score to predict the quality of anticoagulation control in patients with venous thromboembolism treated with vitamin K antagonists: Findings from the RIETE registry

BACKGROUND

The time in therapeutic range (TTR) of patients with venous thromboembolism (VTE) treated with vitamin K antagonists (VKA) is usually below recommended, leading to higher frequency of vascular events, bleeding and mortality. The SAMe-TT2R2 prediction score discriminates those patients with high or low probability of obtaining poor INR control and its use is recommended in patients with atrial fibrillation. Its usefulness has been evaluated in patients with VTE, with conflicting results.

METHOD

We included consecutive patients enrolled in Registro Informatizado Enfermedad TromboEmbolica (RIETE), a prospective multicenter VTE registry, treated with VKA for >90 days and a minimum of 3 INR determinations. We analyzed the relationship between the SAMe-TT₂R₂ score and TTR, determined by the Rosendaal method and by the percentage of INR determinations (after excluding the first month). A ROC curve was calculated considering a cut-off point of TTR ≥65% for good anticoagulation control.

RESULTS

3893 patients were included and classified in high (1411 patients) or low (2482 patients) probability of obtaining poor INR control according to the total score obtained (0-1 points versus 2 points, respectively). TTR, calculated by direct method and Rosendaal method, was 51.2 (±23.4) and 55.4 (±25.9) in the high probability group; and 54.4 (±23.0) and 58.2 (±25.6) in the low probability group, respectively (p < 0.001 for both comparisons). The outcomes were similar between groups. The predictive capacity of the SAMe-TT2R2 score showed an area under the ROC curve of 0.54 (CI 95% 0.52-0.56) and 0.53 (CI 95% 0.51-0.55).

CONCLUSIONS

In patients with VTE treated with VKA, the SAMe-TT2R2 score discriminated those patients with high probability of obtaining poor INR control, but with a low predictive capacity. Further studies are required to assess the usefulness of the score in clinical decision-making.

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.

Quality of anticoagulant therapy and the incidence of in-stent thrombosis after venous stenting

BACKGROUND

In patients with a venous outflow obstruction following iliofemoral deep vein thrombosis stenting of the venous tract to prevent or alleviate postthrombotic syndrome is applied with increasing frequency. The impact of the quality of anticoagulant therapy with vitamin K antagonists (VKAs) on the development of in-stent thrombosis is currently unknown.

OBJECTIVES

To determine the association between the quality of postinterventional VKA treatment and the occurrence of in-stent thrombosis.

METHODS

Seventy-nine patients with iliofemoral and/or caval venous stent placement for obstruction of the venous outflow were included in this study. All patients received postinterventional VKA. The quality of VKA anticoagulant therapy was expressed as the time within therapeutic range (TTR) calculated using the linear interpolation method and as the proportion of International Normalized Ratio (INR) values < 2.0. In-stent thrombosis was assessed by the use of duplex ultrasound. Survival analysis (Kaplan-Meier curves, Cox regression) was used to analyze the data.

RESULTS

In-stent thrombosis developed in 16 patients (20.3%). The total population had a mean TTR of 64.0% (±19.0) and a mean proportion of INR values < 2.0 of 11.6% (±12.0). Overall, a TTR < 49.9% was associated with an increased risk of in-stent thrombosis. The multivariable adjusted analysis showed a hazard ratio (HR) of 0.96 (95% confidence interval [CI], 0.92-0.99; P = .02) per 1% increase in TTR. The proportion of INR values < 2.0 had no significant association with the occurrence of in-stent thrombosis: HR 0.98 (95% CI, 0.91-1.06; P = .66).

CONCLUSIONS

We conclude that the quality of anticoagulant treatment reflected in the TTR following a venous stenting procedure is an important independent determinant for the risk of in-stent thrombosis. The role of anticoagulant treatment for the prevention of in-stent thrombosis following stenting procedures therefore merits further research.

Extended treatment of venous thromboembolism: a systematic review and network meta-analysis

OBJECTIVE

To evaluate efficacy and safety of oral anticoagulant regimens and aspirin for extended venous thromboembolism (VTE) treatment.

METHODS

We searched MEDLINE, Embase, CENTRAL and conference proceedings for randomised controlled trials studying vitamin K antagonists (VKAs), direct oral anticoagulants (DOACs) or aspirin for secondary prevention of VTE beyond 3 months. ORs (95% credible intervals) between treatments were estimated using random-effects Bayesian network meta-analysis.

RESULTS

Sixteen studies, totaling more than 22 000 patients, were included. Compared with placebo or observation and with aspirin, respectively, the risk of recurrent VTE was lower with standard-intensity VKAs (0.15 (0.08 to 0.24) and 0.23 (0.09 to 0.54)), low-dose factor Xa inhibitors (0.16 (0.06 to 0.38) and 0.25 (0.09 to 0.66)), standard-dose factor Xa inhibitors (0.17 (0.08 to 0.33) and 0.27 (0.11 to 0.65)) and the direct thrombin inhibitor (0.15 (0.04 to 0.37) and 0.23 (0.06 to 0.74)) although the risk of major bleeding was higher with standard-intensity VKAs (4.42 (1.99 to 12.24) and 4.14 (1.17 to 18.86)). Effect estimates were consistent in male patients and those with index pulmonary embolism or with unprovoked VTE and in sensitivity analyses. In addition, compared with placebo or observation, the risk of all-cause mortality was reduced with standard-intensity VKAs (0.44 (0.20 to 0.87)) and low-dose factor Xa inhibitors (0.38 (0.12 to 0.995)).

CONCLUSIONS

Standard-intensity VKAs and DOACs are more efficacious than aspirin for extended VTE treatment. Despite a higher risk of major bleeding, standard-intensity VKAs was associated with a lower risk of all-cause mortality. Since overall efficacy and safety of standard-intensity VKAs and DOACs are in equipoise, patient factors, costs and patient preferences should be considered when recommending extending anticoagulation treatment.

Individual and monitoring centre influences upon anticoagulation control of AF patients on warfarin: A longitudinal multi-centre UK-based study

OBJECTIVES

Time within therapeutic INR range (TTR) predicts benefits/risk of warfarin therapy. Identification of individual- and centre-related factors that influence TTR, and addressing them to improve anticoagulation control, are important. This study examined the impact of individual and centre-related factors upon long-term anticoagulation control in atrial fibrillation patients in seven UK-based monitoring services.

METHODS

Data between 2000 and 2014 on 25 270 patients (equating to 203 220 patient years) [18 120 (71.7%) in general practice, 2348 (9.3%) in hospital-based clinics and 4802 (19.0%) in domiciliary service] were analysed.

RESULTS

TTR increased with increasing age, peaking around 77% at 70-75 years, and then declined, was lower in females than males, and in dependent home-monitored patients than those attending clinic (P < 0.0001). TTR, number of dose changes and INR monitoring events and the probability of TTR ≤ 65%, differed across the centres (P < 0.0001).

CONCLUSIONS

Although all the participating centres ostensively followed a standard dosing algorithm, our results indicate that variations in practice do occur between different monitoring sites. We suggest feedback on TTR for individual monitoring sites gauged against the average values reported by others would empower the individual centres to improve quality outcomes of anticoagulation therapy by identifying and adjusting contributory factors within their management system.

Rivaroxaban Versus Warfarin and Risk of Post-Thrombotic Syndrome Among Patients with Venous Thromboembolism

BACKGROUND

The effectiveness of rivaroxaban to reduce post-thrombotic syndrome in patients with venous thromboembolism is largely unknown. We compared rates of post-thrombotic syndrome in patients given rivaroxaban versus warfarin in a cohort of patients with incident venous thromboembolism receiving routine clinical care.

METHODS

We linked Danish nationwide registries to identify all patients with incident venous thromboembolism who were new users of rivaroxaban or warfarin and compared rates of post-thrombotic syndrome using an inverse probability of treatment-weighting approach to account for baseline confounding.

RESULTS

We identified 19,957 oral anticoagulation-naive patients with incident venous thromboembolism treated with warfarin or rivaroxaban (mean age, 64 years; 48% were female, 45.5% had pulmonary embolism). The propensity-weighted rate of post-thrombotic syndrome at 3 years follow-up was 0.53 incidents per 100 person-years with rivaroxaban versus 0.55 per 100 person-years with warfarin, yielding a hazard rate of 0.88 (95% confidence interval, 0.66-1.17). This association remained consistent across types of venous thromboembolism (deep venous thrombosis vs pulmonary embolism, and provoked vs unprovoked venous thromboembolism) and when censoring patients with recurrent venous thromboembolism.

CONCLUSIONS

In this clinical practice setting, rivaroxaban was associated with lower but statistically nonsignificant rates of post-thrombotic syndrome, which did not appear to be mediated only by an effect on recurrent venous thromboembolism.

Predictors and Outcomes of Recurrent Venous Thromboembolism in Elderly Patients

BACKGROUND

Little is known about predictors and outcomes of recurrent venous thromboembolism in elderly patients.

METHODS

We prospectively followed up 991 patients aged ≥65 years with acute venous thromboembolism in a multicenter Swiss cohort study. The primary outcome was symptomatic recurrent venous thromboembolism. We explored the association between baseline characteristics and treatments and recurrent venous thromboembolism using competing risk regression, adjusting for periods of anticoagulation as a time-varying covariate. We also assessed the clinical consequences (case-fatality, localization) of recurrent venous thromboembolism.

RESULTS

During a median follow-up period of 30 months, 122 patients developed recurrent venous thromboembolism, corresponding to a 3-year cumulative incidence of 14.8%. The case-fatality of recurrence was high (20.5%), particularly in patients with unprovoked (23%) and cancer-related venous thromboembolism (29%). After adjustment, only unprovoked venous thromboembolism (sub-hazard ratio, 1.67 compared with provoked venous thromboembolism; 95% confidence interval, 1.00-2.77) and proximal deep vein thrombosis (sub-hazard ratio, 2.41 compared with isolated distal deep vein thrombosis; 95% confidence interval, 1.07-5.38) were significantly associated with recurrence. Patients with initial pulmonary embolism were more likely to have another pulmonary embolism as a recurrent event than patients with deep vein thrombosis.

CONCLUSIONS

Elderly patients with acute venous thromboembolism have a substantial long-term risk of recurrent venous thromboembolism, and recurrence carries a high case-fatality rate. Only 2 factors, unprovoked venous thromboembolism and proximal deep vein thrombosis, were independently associated with recurrent venous thromboembolism, indicating that traditional risk factors for venous thromboembolism recurrence (eg, cancer) may be less relevant in the elderly.

Point-of-care coagulation monitoring: first clinical experience using a paper-based lateral flow diagnostic device

Vitamin K antagonists such as warfarin are the most widely used class of oral anticoagulants. Due to a narrow therapeutic window, patients on warfarin require regular monitoring. Self-testing using point-of-care (POC) diagnostic devices is available, but cost makes this monitoring method beyond reach for many. The main objective of this research was to assess the clinical utility of a low-cost, paper-based lateral flow POC diagnostic device developed for anticoagulation monitoring without the need for a separate electronic reader. Custom-fabricated lateral flow assay (LFA) test strips comprised of a glass fiber sample pad, a nitrocellulose analytical membrane, a cellulose wicking pad, and a plastic backing card were assembled in a plastic cassette. Healthy volunteers and patients on warfarin therapy were recruited for this prospective study. For each participant, a whole blood sample was collected via fingerstick to determine: (1) international normalized ratio (INR) using the CoaguChek® XS coagulometer, (2) hematocrit by centrifugation, and (3) red blood cell (RBC) travel distance on the experimental LFA device after 240 s using digital image analysis. RBC travel distance measured on the LFA device using blood samples obtained from warfarin patients positively correlated with increasing INR value and the LFA device had the capability to statistically distinguish between healthy volunteer INR values and those for patients groups with INR ≥ 2.6. From these data, it is predicted that this low-cost, paper-based LFA device can have clinical utility for identifying anticoagulated patients taking vitamin K antagonists who are outside of the desired therapeutic efficacy window.

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.

Post-thrombotic syndrome in patients treated with rivaroxaban or enoxaparin/vitamin K antagonists for acute deep-vein thrombosis

Post-thrombotic syndrome (PTS) is a common complication of deepvein thrombosis (DVT). Poor quality treatment with vitamin K antagonists (VKA) is a risk factor for PTS. We hypothesised that treatment with the direct oral anticoagulant (DOAC) rivaroxaban may lower PTS incidence as compared to enoxaparin/VKA, as DOACs have a more stable pharmacologic profile than VKA. We performed a post-hoc subgroup analysis of the Einstein DVT trial (n=3449). Kaplan-Meier survival analysis was performed to compare the cumulative incidence of PTS between the rivaroxaban and enoxaparin/VKA groups. Hazard ratios (HR) and 95 % confidence intervals (CI) were calculated using Cox proportional hazards models. We included 336 patients with a mean age of 58 ± 16 years and a median follow-up after index DVT of 57 months (interquartile range 48–64). Of these, 162 (48 %) had been treated with rivaroxaban and 174 (52 %) with enoxaparin/VKA. The cumulative PTS incidence at 60 months follow-up was 29 % in the rivaroxaban group and 40 % in the enoxaparin/VKA group. After adjusting for age, gender, body mass index, previous VTE, ipsilateral recurrent DVT, extent of DVT, idiopathic DVT, duration of anticoagulant treatment, compliance to assigned study medication, elastic compression stocking use and active malignancy, the HR of PTS development for rivaroxaban was 0.76 (95 % CI: 0.51–1.13). In conclusion, treatment of acute DVT with rivaroxaban was associated with a numerically lower but statistically non-significant risk of PTS compared to enoxaparin/VKA treatment. The potential effect on reducing PTS deserves evaluation in a large randomised trial.

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

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.

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.

Chronic complications of venous thromboembolism

Venous thromboembolism (VTE) is a common disease (~700 per 100 000) that is associated with significant risk of recurrence, chronic complications, and substantial mortality, with reported death rates of up to 40% at 10 years. The development of novel anticoagulants has revolutionized the treatment of acute VTE, while strategies for prevention and treatment of chronic complications still seek for such a landmark change. Impaired thrombus resolution is the common denominator behind VTE complications, which are postthrombotic syndrome (PTS) and chronic thromboembolic pulmonary hypertension (CTEPH). PTS and CTEPH are associated with substantial morbidity and high healthcare expenses. While PTS occurs in up to 50% of patients after symptomatic deep vein thrombosis, only a small and poorly defined number of patients are diagnosed with CTEPH after pulmonary embolism. This review is a comprehensive summary of VTE-related chronic complications, their epidemiology, diagnosis, and treatment.

Laboratory determination of old and new targeted anticoagulant agents for prevention of bleeding and thrombotic events in cancer patients

A two-fold prolongation of activated partial thromboplastin time (APTT) is established as therapeutic range for therapy with unfractionated heparin, hirudin and argatroban. The international normalized ratio (INR) of 2 to 3 is required to maintain anticoagulation in the therapeutic range of vitamin K antagonists. The therapeutic range of anti-factor Xa activity during therapy with low-molecular weight heparins and danaparoid are less well and of direct oral anticoagulants (DOAC) poorly defined. The relation of aPTT and INR values to thrombotic and bleeding events are well established despite a large variation of values in affected patients. The relation of coagulation values of the other anticoagulants to clinical events is open. The value of determination in cancer patients is higher because of the increased risk for thrombotic and bleeding events of this patient group. Several activities are currently undertaken to certify methods for in vitro diagnostic testing for DAOCs.

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.

Improvement of time in therapeutic range with warfarin by pharmaceutical intervention

Background Anticoagulation therapy with warfarin is highly effective for prevention and treatment of thromboembolic disorders. Nevertheless, its management is challenging especially in developing countries, where the medical access is difficult and patient education is poor. Objective To determine the effect of pharmaceutical intervention (PI) on the time in therapeutic range (TTR) of a group of anticoagulated patients from our referral center. Method A group of consecutive outpatients previously treated by usual medical care underwent PI. The intervention consisted in the identification and avoidance of food and drug interactions, the confection of medication schedule charts and education to patients regarding side effects and drug monitoring. Mean TTR before and after PI was compared through the Wilcoxon test for repeated measures. Regression analyses were performed to assess the relationship between a TTR level under 65% and potential explanatory variables. Results Mean TTR before PI was 37.4 ± 23.5% and after PI it raised to 67.0 ± 24.9%. Mean change in TTR was +29.5% (95% CI 14.5-44.6; p < 0.001). Before PI only 4 patients had TTR values above 65%, in contrast to 18 patients after PI. Conclusion Our findings support the efficacy of PI to improve TTR values in patients treated with warfarin.

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.

The effect of low-dose oral vitamin K supplementation on INR stability in patients receiving warfarin. A randomised trial

The anticoagulant effect of warfarin is influenced by variations in vitamin K intake. Concomitant use of daily low-dose oral vitamin K (LDVK) and warfarin may improve INR stability. We hypothesise that administration of LDVK improves INR control. To test this hypothesis we performed a multi-centre, placebo-controlled, randomised trial conducted at four university-affiliated hospitals in Canada. Patients on chronic warfarin therapy received oral vitamin K 150 mcg daily or a matching placebo for a total of six months after a one-month run in period. The primary outcome was a comparison of mean time in therapeutic range (TTR) in LDVK and placebo group during a six-month-period. The secondary outcome was number of INR excursions <1.5 or >4.5. There was no significant difference in the final TTR between the two groups (65.1 % vs 66 %, p =0.8). Mean TTR in both LDVK and placebo groups were statistically increased compared with prior to the study. The number of INR excursions were significantly decreased in the LDVK group (9.4 % and 5.4 %, absolute difference [pre- minus post-] = 4 %, 95 % CI, 2 to 6 %, p-value <0.001). We conclude that LDVK administration did not increase mean TTR, but did decrease the number of INR excursions. The observed improvement in mean TTR in both groups suggests that more attentive monitoring of warfarin therapy, rather than LDVK, was responsible for the improvement in TTR observed. The reduced excursions suggest that LDVK did reduce extreme INR variation. The study is registered at www.ClinicalTrial.gov# NCT00990158.

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.

Natural history of bleeding and characteristics of early bleeders among warfarin initiators - a cohort study in Finland

Aims

The demand for oral anticoagulant therapy will continue to increase in the future along with the aging of the population. This study aimed to determine the rate of bleeding requiring hospitalization and to characterize early bleeders among persons initiating warfarin therapy. Characterization of those most susceptible to early bleeding is important in order to increase the safety of warfarin initiation.

Patients and methods

Using data from nationwide health registers, we identified persons initiating warfarin therapy between January 1, 2009 and June 30, 2012, n=101,588, and followed them until hospitalization for bleeding, death, or administrative end of the study (December 31, 2012). We defined early bleeders as persons with a bleeding requiring hospitalization within 30 days since warfarin initiation.

Results

The rate of hospitalization for bleeding during a median follow-up of 1.9 years was 2.6% per person-year (95% confidence interval [CI] 2.5%–2.7%), with a peak within the first 30 days of warfarin initiation (6.5% per person-year, 95% CI 6.0%–7.1%). In a multivariable Cox proportional hazards regression analysis, early bleeders were characterized by prior bleeding (<180 days before initiation, hazard ratio [HR] =13.7, 95% CI 10.9–17.1; during 180 days–7 years before initiation, HR =1.48, 95% CI 1.15–1.90), male sex (HR =1.32, 95% CI 1.10–1.57), older age (HR =1.13, 95% CI 1.04–1.22, per 10-year increase), venous thrombosis (HR =1.83, 95% CI 1.44–2.34), pulmonary embolism (HR =1.46, 95% CI 1.11–1.91), alcohol abuse (HR =1.59, 95% CI 1.08–2.35), rheumatic disease (HR =1.40, 95% CI 1.07–1.83), and exposure to drugs with dynamic interaction mechanism with warfarin (HR =1.43, 95% CI 1.20–1.71). In age-adjusted models, Charlson comorbidity index and number of drugs predicted a graded increase in the hazard of early bleeding.

Conclusion

The rate of hospitalizations for bleeding peaked in the beginning of warfarin therapy. Early bleeders were characterized by venous thrombosis, pulmonary embolism, and factors that increase bleeding risk without affecting the international normalized ratio.

Index clinical manifestation of venous thromboembolism predicts early recurrence type and frequency: a meta-analysis of randomized controlled trials

BACKGROUND

Observational studies suggest index clinical manifestation of venous thromboembolism (VTE) predicts recurrence type. Data regarding the association between index manifestation and recurrence rates are conflicting.

OBJECTIVES

To perform a meta-analysis of randomized controlled trials (RCTs) to determine the type and frequency of recurrent VTE (rVTE) in persons after an index deep vein thrombosis (DVT) or pulmonary embolism (PE).

PATIENTS/METHODS

We searched bibliographic databases for RCTs of acute (early) treatment of rVTE in persons with an index DVT or PE (±DVT), enrolling ≥ 50 subjects anticoagulated ≥ 3-months and reporting types of rVTE. We pooled (random-effects) the proportion of rVTEs that were DVTs, PEs, and fatal PEs, the proportion of recurrent PEs that were fatal, and absolute rVTE rates.

RESULTS

In nine RCTs (N = 13 640; 413 rVTEs) evaluating persons with an index PE; 66% (95% CI, 60-72%) of rVTEs were PE and 27% (95% CI, 22-33%) were fatal PE. Among 25 RCTs (N = 17 340; 692 rVTEs) evaluating persons with an index DVT, 36% (95% CI, 29-44%) experienced a recurrent PE and 10% (95% CI, 7-13%) a fatal PE. Recurrent PEs following an index PE had a higher fatality rate than after an index DVT (41%; 95% CI, 33-48% vs. 25%; 95% CI, 18-33%; P = 0.007). The rVTE rate was higher following an index DVT compared with a PE (2.6%; 95% CI, 1.6-3.8% vs. 4.9%; 95% CI, 4.0-6.0%; P = 0.002).

CONCLUSIONS

Our meta-analysis suggests most rVTEs will be the same type as the index event. While index DVTs are associated with a higher rVTE rate than index PEs; recurrent PEs are associated with high fatality.