Effectiveness of Thromboprophylaxis Agents Following Hip Fracture: A Systematic Review and Network Meta-Analysis

Background

Multiple studies have compared different pharmacologic thromboprophylaxis agents after hip fracture surgery, including aspirin, unfractionated heparin (UFH), low-molecular-weight heparin (LMWH), direct oral anticoagulants (DOAC), and warfarin, resulting in variability in clinical practice. To guide clinical management, a systematic review and network meta-analysis (NMA), which enables the simultaneous assessment of the effects of multiple interventions for the same patient population, was performed. This study aimed to determine the comparative effectiveness of thromboprophylaxis in reducing venous thromboembolism (VTE) in patients with surgically treated hip fractures.

Methods

The primary outcome was the effect of the treatment on the VTE rate, and the secondary outcome was the treatment effect on the bleeding rate. Relevant studies were identified by a systematic search of Embase, MEDLINE, and the Cochrane Central Register of Controlled Trials (CENTRAL) from January 2000 to February 2022. Title, abstract, and full-text screening; data extraction; and risk-of-bias assessment were performed. All studies examining thromboprophylaxis interventions (DOAC, LMWH, UFH, aspirin, and warfarin) in patients with a surgically treated hip fracture were included. Bayesian NMA was performed, and dichotomous outcome data were pooled using the odds ratio. Interventions were ranked using the surface under the cumulative ranking curve (SUCRA) for each outcome.

Results

A total of 19 studies were included after the screening of 466 citations and 77 full-text articles. Of the included studies, 15 studies had a high overall risk of bias. The NMA of the VTE outcome included 19 studies, 49,409 participants, and 6 thromboprophylaxis interventions. The NMA of the bleeding outcome included 3 studies, 18,163 participants, and 3 interventions. The mean age ranged from 43.5 to 86.2 years among the included studies. No thromboprophylaxis intervention was statistically different from any other intervention in its effect on the VTE or bleeding rate in hip fracture patients.

Conclusions

This NMA demonstrated that there was no difference between the thromboprophylaxis interventions in reducing VTE or bleeding rates in hip fracture patients. More robust randomized controlled trials are needed to determine the most effective thromboprophylaxis interventions for patients with hip fractures.

Level of Evidence

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Overexpression of facilitative glucose transporter-3 and membrane procoagulation in maternal platelets of preeclamptic pregnancy

BACKGROUND

Preeclampsia (PE) is a hypertensive disorder during pregnancy that results in significant adverse maternal and neonatal outcomes. Platelet activation is present in PE and contributes to the thrombo-hemorrhagic states of the disorder. However, the mechanisms that initiate and/or sustain platelet activation in PE are ill-defined.

OBJECTIVES

We aimed to characterise this mechanism and the procoagulant potentials of platelets in PE.

METHODS

In this quantitative observational study, we analyzed platelet procoagulant membrane dynamics in patients with PE (n = 21) compared with age-matched normotensive pregnancies (n = 20), gestational hypertension (n = 10), and non-pregnant female controls (n = 19). We analyzed fluorescently labeled indicators of platelet activation, bioenergetics, and procoagulation (phosphatidylserine exposure and thrombin generation), coupled with high-resolution imaging and thrombelastography. We then validated our findings using flow cytometry, immunoassays, classical pharmacology, and convolutional neural network analysis.

RESULTS

PE platelets showed significant ultra-structural remodeling, are more extensively preactivated than in healthy pregnancies and can circulate as microaggregates. Preactivated platelets of PE externalized phosphatidylserine and thrombin formed on the platelet membranes. Platelets' expression of facilitative glucose transporter-1 increased in all pregnant groups. However, PE platelets additionally overexpress glucose transporter-3 to enhance glucose uptake and sustain activation and secretion events. Although preeclampsia platelets exposed to subendothelial collagen showed incremental activation, the absolute hemostatic response to collagen was diminished, and likely contributed to greater blood loss perioperatively.

CONCLUSIONS

We revealed 2 bioenergetic mediators in the mechanism of sustained platelet procoagulation in preeclampsia. Although glucose transporter-1 and glucose transporter-3 remain elusive antiprocoagulant targets, they may be sensitive monitors of PE onset and progression.

Thromboembolic complications after surgical fixation of bone metastases: A systematic review

BACKGROUND

Patients undergoing a major orthopedic surgery for metastatic bone disease (MBD) are at high risk of developing venous thromboembolic (VTE) complications. Despite concerns, there is no consensus on the most effective strategy to prevent VTE in these patients. The purpose of this systematic review was to determine the VTE rate following the surgical management of MBD.

METHODS

The databases MEDLINE, EMBASE, and CENTRAL were searched using keywords related to VTE and MBD requiring surgical management. Included studies reported VTE rates in patients with surgically managed MBD. Descriptive statistics and weighted mean totals were calculated.

RESULTS

In total, 2082 abstracts were screened, and 29 studies were included. The overall VTE rate was 4.7%. Patients receiving surgery for impending pathologic fracture had a higher rate of VTE (5.6%) compared to patients with acute pathologic fractures (4.2%). Low-molecular-weight heparin was the most used chemoprophylaxis.

CONCLUSIONS

Relative to other cancer and orthopedic patients, the VTE rate is extremely high in patients with MBD. The discordant recommendations of thromboprophylaxis, and absence of research in this distinct and more granular surgical oncology subgroup, underpins the challenges associated with developing guidelines to lessen the VTE risks in the MBD patient population.