Low molecular weight heparin bridging for atrial fibrillation: is VTE thromboprophylaxis the major benefit?

Periprocedural heparin bridging in patients receiving oral anticoagulation: a systematic review and meta-analysis

BACKGROUND

Periprocedural heparin bridging therapy aims to reduce the risk of thromboembolic events in patients requiring an interruption in their anticoagulation therapy for the purpose of an elective procedure. The efficacy and safety of heparin bridging therapy has not been well established.

OBJECTIVES

To compare through meta-analysis the effects of heparin bridging therapy on the risk of major bleeding and thromboembolic events of clinical significance among patients taking oral anticoagulants.

METHODS

We searched PubMed, EMBASE and the Cochrane library from January 2005 to July 2016. Studies were included if they reported clinical outcomes of patients receiving heparin bridging therapy during interruption of oral anticoagulant for operations. Data were pooled using random-effects modeling.

RESULTS

A total of 25 studies, including 6 randomized controlled trials and 19 observational studies, were finally included in this analysis. Among all the 35,944 patients, 10,313 patients were assigned as heparin bridging group, and the other 25,631 patients were non-heparin bridging group. Overall, compared with patients without bridging therapy, heparin bridging therapy increased the risk of major bleeding (OR = 3.23, 95%CI: 2.06-5.05), minor bleeding (OR = 1.52, 95%CI: 1.06-2.18) and overall bleeding (OR = 2.83, 95%CI: 1.86-4.30).While there was no significant difference in thromboembolic events (OR = 0.99,95%CI: 0.49-2.00), stroke or transient ischemic attack(OR = 1.45, 95%CI: 0.93-2.26,) or all-cause mortality (OR = 0.71, 95%CI: 0.31-1.65).

CONCLUSIONS

Heparin-bridging therapy increased the risk of major and minor bleeding without decreasing the risk of thromboembolic events and all cause death compared to non-heparin bridging.

Short-Term Risk of Bleeding During Heparin Bridging at Initiation of Vitamin K Antagonist Therapy in More Than 90 000 Patients With Nonvalvular Atrial Fibrillation Managed in Outpatient Care

Background

Several studies have recently examined the risks of bleeding and of ischemic stroke and systemic embolism associated with perioperative heparin bridging anticoagulation in patients with nonvalvular atrial fibrillation. However, few studies have investigated bridging risks during vitamin K antagonist initiation in outpatient settings.

Methods and Results

A retrospective cohort study was conducted on individuals starting oral anticoagulation between January 2010 and November 2014 for nonvalvular atrial fibrillation managed in outpatient care and identified from French healthcare insurance. Bleeding and ischemic stroke and systemic embolism events were identified from the hospitalization database. Adjusted hazard ratios with 95% CI were estimated using Cox models during the first and 2 following months of anticoagulation. Of 90 826 individuals, 30% had bridging therapy. A total of 318 (0.35%) cases of bleeding and 151 (0.17%) ischemic stroke and systemic embolism cases were identified during the first month of follow‐up and 231 (0.31%) and 122 (0.16%) during the 2 following months, respectively. At 1 month of follow‐up, the incidence of bleeding was higher in the bridged group compared with the nonbridged group (0.47% versus 0.30%; P<0.001), and this increased risk persisted after adjustment for covariates (hazard ratio=1.60; 95% CI, 1.28–2.01). This difference disappeared after the first month of treatment (0.93; 0.70–1.23). No significant difference in the occurrence of ischemic stroke and systemic embolism was observed either at 1 month of follow‐up or later.

Conclusions

At vitamin K antagonist initiation for nonvalvular atrial fibrillation managed in ambulatory settings, bridging therapy is associated with a higher risk of bleeding and a similar risk of arterial thromboembolism compared with no bridging therapy.

Comparison of hospital length of stay between hospitalized non-valvular atrial fibrillation patients treated with either apixaban or warfarin

BACKGROUND

Hospital length of stay (LOS) is an important cost driver for hospitals and payers alike. Hospitalized non-valvular atrial fibrillation (NVAF) patients treated with apixaban may have shorter LOS than those treated with warfarin because of the absence of need for INR monitoring in apixaban. Thus, this study compared hospital LOS between hospitalized NVAF patients treated with either apixaban or warfarin.

METHODS

This was a retrospective, observational cohort study based on a large US database including diagnosis, procedure, and drug administration information from >600 acute-care hospitals. Patients selected for study were aged ≥18 years and had a hospitalization record with an ICD-9-CM diagnosis code for atrial fibrillation (AF) in any position from 1 January 2013 to 28 February 2014 (index hospitalization). Patients with diagnoses indicative of rheumatic mitral valvular heart disease or a valve replacement procedure during index hospitalization were excluded. Patients were required to have been treated with either apixaban or warfarin, and not treated with rivaroxaban or dabigatran, during index hospitalization. Apixaban patients were propensity score (PS) matched to warfarin patients at a 1:1 ratio, using patient demographic/clinical and hospital characteristics. The study outcome was hospital LOS, calculated as discharge date minus admission date; a sensitivity analysis calculated hospital LOS as discharge date minus first anticoagulant administration date. Sub-analyses were conducted among patients with a primary diagnosis of AF.

RESULTS

The study included 832 apixaban patients matched to 832 warfarin patients. Mean [standard deviation (SD)] and median hospital LOS were significantly (p < 0.001) shorter in apixaban patients (4.5 [4.2] and 3 days) than in warfarin patients (5.4 [5.0] and 4). Results were consistent in the sensitivity and sub-analyses.

CONCLUSIONS

Among NVAF patients, apixaban treatment was associated with shorter hospital LOS when compared with warfarin treatment. These findings may have important clinical and economic implications for hospitals, payers, and patients.

Heparin bridging in warfarin anticoagulation therapy initiation could increase bleeding in non-valvular atrial fibrillation patients: a multicenter propensity-matched analysis

BACKGROUND

The efficacy of heparin-bridging therapy during the initiation of oral anticoagulation therapy (OAC) in non-valvular atrial fibrillation (NVAF) is unclear.

OBJECTIVES

To evaluate the efficacy and the safety of heparin-bridging therapy during OAC initiation in NVAF patients.

PATIENTS/METHODS

This study included 5327 consecutive warfarin-naïve NVAF patients who received OAC that was initiated with (n = 1053) or without (n = 4274) heparin bridging at four tertiary hospitals. Stroke and bleeding events within 30 days of OAC were evaluated.

RESULTS

While there was no difference in the incidence of stroke (0.5% vs. 0.3%, P = 0.381), major bleeding rate (0.9% vs. 0.3%, P = 0.004) was higher in heparin-bridged than in non-bridged patients. This trend remained in the propensity score-matched population (stroke 0.5% vs. 0.6%, P = 0.762; major bleeding 0.8% vs. 0.1%, P = 0.019). A high CHA2 DS2 -VASc score was an independent predictor for stroke, whereas bridging therapy had no beneficial effect in preventing stroke regardless of CHADS2 or CHA2 DS2 -VASc scores. The HAS-BLED score had a predictive value for major bleeding (odds ratio 1.80, 95% confidence interval 1.11-2.92, P = 0.018), and heparin-bridging therapy was associated with a higher major bleeding rate (odds ratio 4.44, 95% confidence interval 1.68-11.72, P = 0.003), especially in patients with a HAS-BLED score of ≥ 1.

CONCLUSIONS

The heparin-bridging therapy increased bleeding without the benefit of preventing stroke at the initiation of OAC in NVAF. Our data suggest that heparin bridging should not be considered at the initiation of OAC in NVAF patients.

Hospital length of stay of nonvalvular atrial fibrillation patients who were administered Rivaroxaban versus Warfarin with and without pretreatment parenteral anticoagulants therapies

BACKGROUND

Warfarin has been the only anticoagulant used for decades to prevent strokes and systemic embolisms in nonvalvular atrial fibrillation (NVAF) patients. Compared with rivaroxaban, warfarin has a narrow therapeutic range and many genetic and food-drug interactions that could potentially prolong hospital length of stay (LOS).

OBJECTIVE

To compare hospital LOS between NVAF patients who were administered rivaroxaban versus warfarin with and without pretreatment of parenteral anticoagulant agents in a population of rivaroxaban-treated patients.

METHODS

A retrospective matched-cohort analysis was conducted using the Premier Perspective Comparative Hospital Database from November 2010 to September 2012. Adult patients were included in the study if they had a hospitalization for NVAF. Rivaroxaban users were matched with up to 4 warfarin users based on propensity score analyses. Patients with and without pretreatment of parenteral anticoagulant agents were evaluated separately. Hospital LOS was compared between treatment groups using generalized estimating equations.

RESULTS

The matched cohorts' characteristics were well balanced. Among the matched rivaroxaban and warfarin users who were administered parenteral agents, the mean age of the cohorts was 70 years and 47% of patients were female, whereas in the sample of patients who were not administered parenteral agents, the mean age was 72 years and 50% of patients were female. In the sample of patients who were administered parenteral agents, rivaroxaban users had significantly shorter hospital LOS (LOS difference: 1.38 days, P < 0.001) compared with warfarin users among rivaroxaban-treated patients. No significant difference in LOS was found in the sample of patients who were not administered parenteral anticoagulant agents (P = 0.169).

CONCLUSION

In the study sample of NVAF patients who were administered parenteral anticoagulant agents, rivaroxaban was associated with a significantly shorter hospital LOS compared with warfarin. The difference in LOS was not statistically significant in the sample of patients who were not administered parenteral anticoagulant agents.

Bioengineering murine mastocytoma cells to produce anticoagulant heparin

Heparin (HP), an important anticoagulant polysaccharide, is produced in a complex biosynthetic pathway in connective tissue-type mast cells. Both the structure and size of HP are critical factors determining the anticoagulation activity. A murine mastocytoma (MST) cell line was used as a model system to gain insight into this pathway. As reported, MST cells produce a highly sulfated HP-like polysaccharide that lacks anticoagulant activity (Montgomery RI, Lidholt K, Flay NW, Liang J, Vertel B, Lindahl U, Esko JD. 1992. Stable heparin-producing cell lines derived from the Furth murine mastocytoma. Proc Natl Acad Sci USA 89:11327-11331). Here, we show that transfection of MST cells with a retroviral vector containing heparan sulfate 3-O-sulfotransferase-1 (Hs3st1) restores anticoagulant activity. The MST lines express N-acetylglucosamine N-deacetylase/N-sulfotransferase-1, uronosyl 2-O-sulfotransferase and glucosaminyl 6-O-sulfotransferase-1, which are sufficient to make the highly sulfated HP. Overexpression of Hs3st1 in MST-10H cells resulted in a change in the composition of heparan sulfate (HS)/HP and CS/dermatan sulfate (DS) glycosaminoglycans. The cell-associated HS/HP closely resembles HP with 3-O-sulfo group-containing glucosamine residues and shows anticoagulant activity. This study contributes toward a better understanding of the HP biosynthetic pathway with the goal of providing tools to better control the biosynthesis of HP chains with different structures and activities.

Anticoagulant use, the prevalence of bridging, and relation to length of stay among hospitalized patients with non-valvular atrial fibrillation

Objective: The objectives of this study were to describe inpatient anticoagulation and bridging in patients with non-valvular atrial fibrillation (NVAF) and to identify whether differences exist in length of stay (LOS) among bridged versus non-bridged NVAF patients.

Design: Administrative claims data were used to select patients ≥18 years with a primary or secondary discharge diagnosis of NVAF and inpatient warfarin use from 1 July 2004 to 30 September 2009. Patients with valvular or transient causes of NVAF or pregnancy were excluded. Inpatient bridging was defined as receipt of an anticoagulant in addition to warfarin during the hospitalization. LOS was reported for non-bridged patients (warfarin only) and compared with three bridging regimens: low molecular weight heparin/pentasaccharide (LMWH/PS); unfractionated heparin (UFH); and two-agent bridging (LMWH/PS and UFH). Multivariate analyses were performed to evaluate the association between bridging and LOS, adjusting for demographic and clinical variables.

Results: Of 6340 NVAF patients, 48% received inpatient warfarin (mean LOS 5.5 days); among them, 64% received bridging therapy (mean LOS 6.3 days) [LMWH/PS 45% (mean LOS 5.6 days), UFH 36% (mean LOS 6.0 days), two-agent bridging 18% (mean LOS 8.4 days)]. Following multivariate analysis, relative to patients who received inpatient warfarin only, LOS was significantly higher for patients with UFH (19.3%) and patients with two-agent bridging (45.1%). Patients with pre-period warfarin, cancer, or diabetes mellitus who received bridging agents had significantly longer LOS than patients with those conditions who were not bridged.

Conclusion: LOS was longer for bridged than non-bridged patients. Further studies are needed to identify predictors of bridging and to explain why bridged NVAF patients had longer LOS.

Striking a balance between the risks and benefits of anticoagulation bridge therapy in patients with atrial fibrillation: clinical updates and remaining controversies

Long-term anticoagulation with a vitamin K antagonist (VKA) or the new agent dabigatran is recommended to decrease stroke risk in patients with atrial fibrillation. When patients with atrial fibrillation undergo initiation or interruption of VKA therapy, or experience an isolated subtherapeutic international normalized ratio (INR), bridge therapy with a parenteral anticoagulant may be considered. To describe the literature for anticoagulation bridge therapy in patients with atrial fibrillation, we conducted a MEDLINE search (1966-February 2011) of the English-language literature to identify related studies. Ongoing clinical trials were identified through a search of the ClinicalTrials.gov registry. Major national and international guidelines were gathered and evaluated. Additional literature was obtained through review of relevant references of the identified articles. Bridging is not supported by guidelines or clinical trials for patients starting VKA therapy for atrial fibrillation. A subtherapeutic INR value during long-term VKA therapy may be associated with increased thromboembolic events, but the benefit of bridging has not been demonstrated. When VKA therapy is interrupted for procedures, retrospective and cohort data suggest that the decision to bridge should be based on a patient's thromboembolic and bleeding risks associated with the procedure. Typically, it is recommended to use bridge therapy in patients with atrial fibrillation at high risk for thromboembolism, but the benefit of bridging is less clear in patients at low risk. Not all procedures necessitate anticoagulation interruption. Recent trials suggest that VKAs can be continued when patients are undergoing cardiac device procedures and some types of radiofrequency ablation. Several clinical trials are ongoing that will provide more definitive guidance for perioperative anticoagulation management of patients with atrial fibrillation. Patients taking dabigatran are unlikely to require bridge therapy because of a predictable anticoagulant effect and rapid onset of action. However, evidence for optimal perioperative management of dabigatran is needed.