The use of direct oral anticoagulants for extended duration thromboprophylaxis in medically ill patients: a systematic review and meta-analysis

Predicting post-discharge venous thromboembolism and bleeding among medical patients: External validation of a novel risk score utilizing ubiquitous biomarkers

BACKGROUND

Post-hospitalization thromboprophylaxis can reduce venous thromboembolism (VTE) risk for non-surgical patients but may carry bleeding risks. We aimed to externally validate the Intermountain Risk Scores for hospital-associated venous thromboembolism (HA-VTE IMRS) and major bleeding (HA-MB IMRS) for VTE and bleeding outcomes.

METHODS

Retrospective cohort study of adult patients discharged alive from medical services between 2015 and 2019. HA-VTE IMRS and HA-MB IMRS were calculated at the time of hospital discharge and dichotomized as high- or low-risk as described in the derivation manuscript. 90-day post-discharge VTE outcomes were assessed from diagnostic radiology reports, and bleeding outcomes were assessed using ICD-10 codes and blood bank transfusion records.

RESULTS

Among 113,578 patients in the study, 66,340 patients (58.4 %) had a low-risk HA-VTE IMRS <7, versus 47,238 (41.6 %) high-risk ≥7. For bleed prediction, 71,576 patients (63 %) had a low-risk HA-MB IMRS <8, versus 42,002 (37 %) high-risk ≥8. VTE incidence was 1.1 % and 0.6 % while major bleeding incidence was 1.3 % and 0.1 % in high-risk versus low-risk cohorts, respectively. AUCs for VTE and bleed outcome discrimination were 0.59 and 0.78, respectively. Patients with a combined high-risk VTE score and low-risk bleeding score comprised 14.5 % of the population.

CONCLUSION

In this external validation study, the HA-VTE IMRS had poor discrimination for VTE but the HA-MB IMRS had good discriminatory ability for major bleeding events. A sizable minority of patients were categorized as high VTE risk with low bleed risk, a population which may have an optimal risk-benefit profile for post-hospital thromboprophylaxis.

Pharmacology of Heparin and Related Drugs: An Update

Heparin has been used extensively as an antithrombotic and anticoagulant for close to 100 years. This anticoagulant activity is attributed mainly to the pentasaccharide sequence, which potentiates the inhibitory action of antithrombin, a major inhibitor of the coagulation cascade. More recently it has been elucidated that heparin exhibits anti-inflammatory effect via interference of the formation of neutrophil extracellular traps and this may also contribute to heparin's antithrombotic activity. This illustrates that heparin interacts with a broad range of biomolecules, exerting both anticoagulant and nonanticoagulant actions. Since our previous review, there has been an increased interest in these nonanticoagulant effects of heparin, with the beneficial role in patients infected with SARS2-coronavirus a highly topical example. This article provides an update on our previous review with more recent developments and observations made for these novel uses of heparin and an overview of the development status of heparin-based drugs. SIGNIFICANCE STATEMENT: This state-of-the-art review covers recent developments in the use of heparin and heparin-like materials as anticoagulant, now including immunothrombosis observations, and as nonanticoagulant including a role in the treatment of SARS-coronavirus and inflammatory conditions.

Post-discharge thrombosis and bleeding in medical patients: A novel risk score derived from ubiquitous biomarkers

BACKGROUND

Some hospitalized medical patients experience venous thromboembolism (VTE) following discharge. Prophylaxis extended beyond hospital discharge (extended duration thromboprophylaxis [EDT]) may reduce this risk. However, EDT is costly and can cause bleeding, so selecting appropriate patients is essential. We formerly reported the performance of a mortality risk prediction score (Intermountain Risk Score [IMRS]) that was minimally predictive of 90-day hospital-associated venous thromboembolism (HA-VTE) and major bleeding (HA-MB). We used the components of the IMRS to calculate de novo risk scores to predict 90-day HA-VTE (HA-VTE IMRS) and major bleeding (HA-MB IMRS).

METHODS

From 45 669 medical patients we randomly assigned 30 445 to derive the HA-VTE IMRS and the HA-MB IMRS. Backward stepwise regression and bootstrapping identified predictor covariates from the blood count and basic chemistry. These candidate variables were split into quintiles, and the referent quintile was that with the lowest event rate for HA-VTE and HA-MB; respectively. A clinically relevant rate of HA-VTE and HA-MB was used to inform outcome rates. Performance was assessed in the derivation set of 15 224 patients.

RESULTS

The HA-VTE IMRS and HA-MB IMRS area under the receiver operating curve (AUC) in the derivation set were 0.646, and 0.691, respectively. In the validation set, the HA-VTE IMRS and HA-MB IMRS AUCs were 0.60 and 0.643.

CONCLUSIONS

Risk scores derived from components of routine labs ubiquitous in clinical care identify patients that are at risk for 90-day postdischarge HA-VTE and major bleeding. This may identify a subset of patients with high HA-VTE risk and low HA-MB risk who may benefit from EDT.

A clinical focus on the use of extended-duration thromboprophylaxis in medically ill patients

PURPOSE

This review describes and analyzes literature to provide recommendations for use of extended-duration thromboprophylaxis (EDT) in medically ill patients.

SUMMARY

Guidelines recommend pharmacologic thromboprophylaxis for patients at increased thrombosis risk during hospitalization and recommend against extending thromboprophylaxis beyond hospitalization. Despite these recommendations, observational data demonstrate that venous thromboembolism (VTE) risk persists following hospital discharge. A MEDLINE literature search was performed to identify original research evaluating the safety and efficacy of EDT. Eight meta-analyses and 5 randomized controlled trials-each varying in the agents studied (enoxaparin, rivaroxaban, apixaban, and betrixaban)-were selected for inclusion. Collectively, the evaluated data demonstrates that EDT reduces the incidence of VTE at the expense of increasing the risk of major bleeding and without providing mortality reduction. Variations in enrollment criteria, differences in EDT strategies, and uncertainty regarding proper patient selection limit the applicability of EDT in practice. Rivaroxaban and betrixaban gained Food and Drug Administration (FDA) approval on the basis of results of the APEX and MARINER trials and a post hoc analysis of the MAGELLEN trial results. Although a number of agents are FDA approved for use in EDT, clinicians must carefully weigh the risks vs benefits of EDT with these agents until studies demonstrate a more favorable risk-benefit profile.

CONCLUSION

Evidence to support EDT in medically ill patients is inconclusive and has highlighted the need for an individualized approach. The reviewed evidence supports guideline recommendations from both the American College of Chest Physicians and the American Society of Hematology that recommend against routine use of EDT in the majority of medically ill patients. Future studies are needed to optimize the risk-benefit profile of EDT and to ensure proper patient selection.

Challenging anticoagulation cases: A case of pulmonary embolism shortly after spontaneous brain bleeding

Venous thromboembolism (VTE) is a common complication after intracranial hemorrhage (ICH); the incidence has been reported to vary between 18% to 50% for deep vein thrombosis and between 0.5% to 5% for pulmonary embolism (PE). According to current clinical practice guidelines, patients with acute VTE should receive anticoagulant treatment for at least 3 months in the absence of contraindications. Anticoagulant treatment reduces mortality, prevents early recurrences and improves long-term outcome in patients with acute VTE. However, recent ICH is an absolute contraindication for anticoagulant treatment due to the potential increased risk of hematoma expansion or recurrent ICH. Hematoma expansion occurs in approximately a third of patients within 24 h following the diagnosis of a spontaneous ICH. The risk for recurrent ICH depends on patients' features as well as on the feature of index ICH. Limited evidence is available on the risks of therapeutic anticoagulation started shortly after ICH. Expert consensus around the introduction of therapeutic anticoagulation suggests delaying therapeutic anticoagulation for at least 2 weeks after spontaneous ICH, until the risk re-bleeding becomes acceptable. Vena cava filters should be inserted to reduce the risk for (non) fatal PE until therapeutic anticoagulation can be started; antithrombotic prophylaxis should be started as soon as possible to avoid recurrent VTE after vena cava filter insertion. For patients presenting PE with hemodynamic compromise, percutaneous embolectomy should be considered. Most patients will be able to receive anticoagulant treatment within 4 weeks following spontaneous ICH; direct oral anticoagulants are probably the treatment of choice for those ICH patients tolerating anticoagulant treatment.

Is Extended-Duration (Post-Hospital Discharge) Venous Thromboembolism Chemoprophylaxis Safe and Efficacious in High-Risk Surgery Patients? A Systematic Review

BACKGROUND

The risk of venous thromboembolism (VTE) persists beyond hospitalization in surgical patients, yet post-hospital discharge chemoprophylaxis regimens are not common. The purpose of this study is to systematically review the literature regarding extended-duration (post-hospital discharge) venous thromboembolism chemoprophylaxis and to determine whether it is warranted in high-risk surgical patients, as determined by its safety and efficacy.

METHOD

We searched four online databases for articles evaluating extended-duration (post-hospital discharge) VTE chemoprophylaxis regimens in surgical patients between the years January 2000 and February 2020. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were used. GRADE methodology and the Cochrane Risk of Bias Assessment Tool for Randomized Controlled Trials were used to grade the quality of evidence and assess risk of bias.

RESULTS

Nineteen studies with 10,544 patients were analyzed. The duration for extended-duration VTE chemoprophylaxis ranged from 7 to 42 days. In our study cohort, high-risk patients not prescribed extended-duration VTE chemoprophylaxis had a mean VTE incidence rate of 12.23%, while patients receiving 28-30 days of chemoprophylaxis had a mean VTE incidence rate of 4.37% (p = 0.006). The risk of bleeding events did not correlate with the duration of chemoprophylaxis.

CONCLUSION

Extended-duration VTE chemoprophylaxis in high-risk surgical patients decreased the incidence of thrombotic complications without increasing the risk of bleeding events. Further research is needed to establish guidelines for the optimal duration of VTE chemoprophylaxis in high-risk surgical patients.

LEVEL OF EVIDENCE

III.