Safety and effectiveness of aspirin and enoxaparin for venous thromboembolism prophylaxis after total hip and knee arthroplasty: a systematic review

Aspirin Versus Other Anticoagulants for the Initial Prevention of Venous Thromboembolism Following Elective Total Hip and Knee Arthroplasty: An Umbrella Review and Meta-Analysis

BACKGROUND

Reducing venous thromboembolism (VTE) events is crucial to improving outcomes following total joint arthroplasties. Aspirin, low-molecular-weight heparin (LMWH), factor Xa inhibitors, and warfarin have been investigated to prevent VTE after surgery, but the best option remains uncertain. Our study aimed to clarify aspirin's prophylactic role in hip and knee arthroplasty through an umbrella analysis.

METHODS

PubMed, Web of Science, Scopus, and Embase databases were queried on September 7, 2023, to identify all published systematic reviews and meta-analyses evaluating the efficacy and safety of aspirin in preventing VTE after primary or revision total hip and total knee arthroplasties. The methodological quality of the included studies was assessed using the "A Measurement Tool to Assess Systematic Reviews 2" (AMSTAR-2) critical appraisal tool. There were two independent reviewers who extracted data focusing on thromboembolic events, bleeding, and mortality rates.

RESULTS

There were 19 systematic reviews and meta-analyses included. The overall risk of deep venous thrombosis was comparable in the aspirin versus non-aspirin group (OR [odds ratio] = 1.20; 95% CI [confidence interval] = 0.86 to 1.68). Aspirin reduced the risk of pulmonary emboli by 0.58%, while other anticoagulants showed a similar reduction of 0.6%, which was not statistically significant (OR = 1.26; 95% CI = 0.76 to 2.07; I2 = 94%). Aspirin significantly reduced total bleeding risk by 30% compared to other anticoagulants (0.33 versus 1.05%; OR = 0.7; 95% CI = 0.58 to 0.85; I2 = 2%). The all-cause mortality rate did not significantly differ between aspirin (0.18%) and other anticoagulants (0.14%) (OR = 1.25; 95% CI = 0.79 to 1.97).

CONCLUSION

Aspirin is a viable chemoprophylactic option following primary or revision total hip and knee arthroplasty due to its availability, cost-effectiveness, ease of administration, lack of routine blood monitoring requirement, and comparative effectiveness to other anticoagulants.

Factors related to deep vein thrombosis as a complication of post-total hip arthroplasty patients: a systematic review

INTRODUCTION

Deep vein thrombosis (DVT) is a significant complication following total hip arthroplasty (THA), leading to morbidity and mortality. The incidence of DVT in THA varies, with reported rates ranging from 12 to 23% in Europe and North America. The risk of DVT is compounded by pulmonary embolism, making prevention essential. Despite advancements in perioperative care, venous thromboembolism remains a major concern, necessitating improved preventive measures and risk stratification models.

METHODS

A systematic review was conducted using PubMed, Scopus, and Cochrane databases with the keywords "total hip arthroplasty," "deep vein thrombosis," and "risk." Studies examining DVT risk factors in THA patients were included. Nine studies met the inclusion criteria and were analyzed. The search followed PRISMA 2020 guidelines to ensure methodological rigor and minimize bias.

RESULTS

Nine studies identified significant risk factors for DVT following THA. Advanced age, elevated D-dimer levels, and malnutrition were notable preoperative risks. Additional factors included BMI ≥ 28, diabetes, bilateral replacements, prolonged surgery duration, and cemented prostheses. Recent studies highlighted chronic obstructive pulmonary disease and congestive heart failure as independent predictors, emphasizing the need for preoperative cardiopulmonary assessment. Hip function was not associated with preoperative DVT.

CONCLUSION

Multiple factors influence DVT risk post-THA. Identifying these risks enables targeted interventions to reduce DVT incidence. Tailored prophylactic strategies, including individualized anticoagulation and enhanced mobilization protocols, should be prioritized. Further research is needed to refine prevention strategies.

The efficacy and safety of aspirin in preventing venous thrombosis in major orthopedic surgery: An updated meta-analysis of randomized controlled trials

BACKGROUND

Major orthopedic surgery, including hip and knee replacement and lower extremity trauma fractures surgery, is associated with a high risk of venous thromboembolism (VTE), especially proximal deep vein thrombosis (DVT), and pulmonary embolism (PE), and is linked with high morbidity and mortality rates. Chemical anticoagulation is routinely used to prevent VTE, with previous meta-analyses reporting on the efficacy and safety of aspirin and other anticoagulants, however, opinions are divided. In the past 2 years, several large randomized controlled trials have been published, therefore, we reanalyzed aspirin efficacy and safety when compared with other anticoagulants in preventing VTE in major orthopedic surgery.

METHODS

Using PubMed, The Cochrane Library, Embase, and Web of Science databases, we conducted a RCT search in August 2023. The main outcomes included VTE, proximal DVT or PE. Additional outcomes included bleeding events, wound complications, wound infections, blood transfusions, and death events.

RESULTS

In total, 17 eligible articles, involving 29,522 patients (15,253 aspirin vs 14,269 other anticoagulant cases), were included. Primary outcomes showed that VTE incidence was more high in the aspirin group when compared with other anticoagulants (risk ratio [RR] = 1.45, 95% confidence interval [CI] = 1.18-1.77, P = .0004) and proximal in the aspirin group the DVT and/or PE incidence was significantly higher in the aspirin group when compared with other anticoagulants (RR = 1.19, 95% CI = 1.02-1.39, P = .03). No significant secondary outcome differences were identified in the aspirin group when compared with other anticoagulants (bleeding events [RR] = 0.83, 95% CI = 0.63-1.10, P = .20); wound complications (RR = 0.45, 95% CI = 0.20-1.04, P = .06); wound infection (RR = 1.08, 95% CI = 0.85-1.38, P = .53); blood transfusion events (RR = 1.00, 95% CI = 0.84-1.19, P = 1.00) and death events (RR = 1.11, 95% CI = 0.78-1.57, P = .55).

CONCLUSIONS

Our updated meta-analysis showed that aspirin was inferior to when compared with other anticoagulants in VTE-related orthopedic major surgery, including proximal DVT and/or PE, and was more likely to form VTE. No differences between groups were identified for bleeding, wound complications, wound infections, transfusion, or death events.

Efficacy and safety of salvianolate and enoxaparin in the prevention of perioperative deep venous thrombosis in gastrointestinal surgery

OBJECTIVE

In this study, the efficacy and safety of salvianolate were compared with enoxaparin in the prevention of perioperative deep vein thrombosis in gastrointestinal surgery.

METHODS

From October 2017 to September 2019, 563 patients who underwent gastrointestinal surgery were collected. Based on the inclusion and exclusion criteria, 119 patients were divided into two groups: enoxaparin group (n = 65) and salvianolate group (n = 54). Comparisons were made regarding the outcomes: prothrombin time (PT), prothrombin activity (PTA), international normalized ratio (INR), activated partial thromboplastin time (APTT), fibrinogen (FIB), thrombin time (TT), D-dimer level (D-D), platelet count (PLT), hematokrit (HCT), and incidence of deep vein thrombosis (DVT).

RESULTS

The main outcomes showed no significance between enoxaparin group and salvianolate group (p > .05). The incidence of DVT in salvianolate group was 1.85%, significantly lower than that in enoxaparin group (12.3%) (p < .05). No serious adverse reactions occurred in the two groups during treatment.

CONCLUSION

Compared with enoxaparin, salvianolate has an advantage in the prevention of perioperative thrombosis in gastrointestinal surgery with a lower incidence of DVT.

Effectiveness of different antithrombotic agents in combination with tranexamic acid for venous thromboembolism prophylaxis and blood management after total knee replacement: a prospective randomized study

BACKGROUND

Tranexamic acid (TXA) has been widely applied in total knee arthroplasty (TKA) to significantly reduce perioperative blood loss and improve knee function recovery in patients after surgery. The choice of antithrombotic agents for venous thromboembolism (VTE) prevention after TKA is controversial. Therefore, this study aimed to compare the effects of different antithrombotic agents on patients after primary unilateral TKA in the context of applied TXA.

METHODS

A total of 180 patients undergoing primary unilateral TKA from October 2020 to December 2021 were included in this study. All patients were given an intraoperative drip of 60 mg/kg TXA. Thereafter, patients were divided into three groups (n = 60 each). Baseline data were comparable among the three groups. The average follow-up time was 3.02 ± 0.09 months. Group 1 enrolled patients receiving oral rivaroxaban (RA) at 10 mg, Group 2 included patients who received subcutaneous Dalteparin sodium at 2500 IU, while Group 3 included patients taking oral aspirin (ASA) at 100 mg. Patients in all the three groups received treatment once a day for 30 days at 12 h postoperatively. The primary outcomes in this study were post-treatment drainage volume and thrombotic complication rate. The secondary outcomes included hematologic parameters, transfusion rate, intraoperative blood loss, total blood loss (TBL), and bleeding complication rate.

RESULTS

The average drainage volume after treatment was significantly lower in Group 3 than in Group 1 and Group 2 (205.2 ± 69.0 vs 243.4 ± 72.5 vs 295.4 ± 72.5 ml, P < 0.001), and there was a significant difference between Group 1 and Group 2 (243.4 ± 72.5 mL vs 295.4 ± 72.5 mL, P < 0.001). The blood transfusion rate of Group 2 dramatically increased compared with Group 1 and Group 3 (20.0% vs 6.7% vs 5.0%, P = 0.01). The bleeding complication rate in Group 1 apparently increased relative to Group 2 and Group 3 (26.7% vs 10.0% vs 8.3%, P = 0.008). Besides, there was no significant difference in the thrombotic complication rate among the three groups.

CONCLUSION

Under the background of TXA application, ASA, RA, and Dalteparin sodium were all effective on preventing VTE after TKA. In addition, ASA effectively reduced post-treatment Hemoglobin (Hb) loss, drainage volume, TBL, transfusion rate, and bleeding complications compared with RA and Dalteparin sodium.

TRIAL REGISTRATION

The trial was registered at the Chinese Clinical Trial Registry (ChiCTR2200060169). Date of Registration: 21/05/2022.

[Low molecular weight heparin combined with aspirin to prevent perioperative venous thromboembolism in patients with splenic rupture and lower extremity fracture]

OBJECTIVE

To investigate the effectiveness and safety of low molecular weight heparin combined with aspirin for perioperative prophylactic anticoagulation in patients with lower extremity fracture after splenectomy.

METHODS

The clinical data of 50 patients with splenic rupture combined with lower extremity fracture between January 2009 and June 2022 were retrospectively analyzed. All patients were given enoxaparin sodium at 48 hours after splenectomy, and stopped at 24 hours before fracture surgery. After fracture surgery, the patients were divided into aspirin group (group A, 15 cases), low molecular weight heparin group (group B, 16 cases), and low molecular weight heparin combined with aspirin group (group C, 19 cases) according to different anticoagulation regimens. The treatment course was 28 days. There was no significant difference in gender, age, body mass index, cause of injury, fracture site, time from injury to operation, complications, and other general data between groups ( P>0.05). The occurrence of venous thromboembolism (VTE) was observed; hemoglobin (Hb), platelet (PLT), D-D dimer, and fibrinogen degradation product (FDP) were recorded before operation and at 1, 3, and 7 days after operation, and the effect of anticoagulation regimen on coagulation function was observed. The incidences of wound complications and bleeding related complications were recorded, and the total perioperative blood loss, hidden blood loss, and overt blood loss were calculated.

RESULTS

The incidences of VTE in groups A, B, and C were 13.33% (2/15), 12.50% (2/16), and 5.26% (1/19), respectively, and there was no significant difference between groups ( χ ²=0.770, P=0.680). There was no portal vein thrombosis and no VTE-related death in the 3 groups. There was no significant difference in the levels of Hb, PLT, D-D dimer, and FDP between groups before and after operation ( P>0.05); and there was no significant difference in total perioperative blood loss, hidden blood loss, and overt blood loss between groups ( P>0.05). No local skin necrosis was found in all patients. In group A, 1 case occurred redness and swelling of incision; in group B, 1 case had incision discharge, redness, and swelling, and 1 case had fat liquefaction; in group C, 1 case had repeated incision exudation accompanied by local tissue redness and swelling, and 1 case had local hematoma. The incidences of adverse incision in groups A, B, and C were 6.66% (1/15), 12.50% (2/16), and 11.76% (2/19), respectively, with no significant difference ( χ ²=0.302, P=0.860). There were 4 cases of bleeding related complications, including 1 case of incision ecchymosis in groups A and B respectively, with the incidence of 6.66% and 6.25%, respectively; there was 1 case of incision hematoma and 1 case of bleeding in group C, with the incidence of 11.76%; showing no significant difference in the incidence of bleeding related complications between groups ( χ ²=0.268, P=0.875).

CONCLUSION

Perioperative combined use of low molecular weight heparin and aspirin for prevention of anticoagulation in patients with splenic rupture and lower extremity fracture can effectively prevent the occurrence of VTE without increasing the incidence of complications, which is an effective and safe treatment method. However, whether the incidence of VTE can be reduced needs to be further studied by expanding the sample size.

Incidence and risk factors associated with venous thromboembolism following primary total hip arthroplasty in low-risk patients when using aspirin for prophylaxis

AIMS

The primary aim was to assess the incidence of venous thromboembolism (VTE) following total hip replacements (THR) in a low-risk patient group when using 150 mg aspirin as the pharmacological component of VTE prophylaxis on discharge. The secondary aim was to identify factors associated with an increased risk of a VTE event in this low-risk group.

PATIENTS AND METHODS

Retrospective review of a consecutive cohort of patients undergoing THR during a 63-month period. Patient demographics, socio-economic status, ASA grade, type of anaesthetic, length of surgery and BMI were recorded. A diagnosis of VTE was assigned to symptomatic patients with positive imaging for a deep vein thrombosis (DVT) and/or a pulmonary embolism (PE) within 8 weeks of surgery. Multivariate logistic regression modeling was used to identify factors associated with VTE after THR.

RESULTS

3880 patients underwent THR during the study period, of which 2740 (71%) were low risk and prescribed aspirin for VTE prophylaxis. There were 34 VTE events, of which 15 were DVTs and 18 were PEs, with 1 patient diagnosed with both. The incidence of VTE was 1.2%, with no VTE-related deaths. Patients incurring a VTE postoperatively were more likely to be male (odds ratio [OR] 2.06, p = 0.022), of older age (OR 0.43, p = 0.047) and were more likely to be socially deprived (OR 0.32, p = 0.006). There was no significant difference with patients given low-molecular-weight heparin (LMWH) as an inpatient prior to discharge on aspirin (p = 0.806), nor any difference with the type of anaesthetic used during surgery (p = 0.719).

CONCLUSIONS

Aspirin is a relatively safe and effective choice for VTE prophylaxis in low-risk patients undergoing THR. Male sex and age >70 years were twice as likely to sustain a VTE and patients from the most deprived socio-economic background are 3 times as likely.

Identification of Kukoamine A, Zeaxanthin, and Clexane as New Furin Inhibitors

The endogenous protease furin is a key protein in many different diseases, such as cancer and infections. For this reason, a wide range of studies has focused on targeting furin from a therapeutic point of view. Our main objective consisted of identifying new compounds that could enlarge the furin inhibitor arsenal; secondarily, we assayed their adjuvant effect in combination with a known furin inhibitor, CMK, which avoids the SARS-CoV-2 S protein cleavage by means of that inhibition. Virtual screening was carried out to identify potential furin inhibitors. The inhibition of physiological and purified recombinant furin by screening selected compounds, Clexane, and these drugs in combination with CMK was assayed in fluorogenic tests by using a specific furin substrate. The effects of the selected inhibitors from virtual screening on cell viability (293T HEK cell line) were assayed by means of flow cytometry. Through virtual screening, Zeaxanthin and Kukoamine A were selected as the main potential furin inhibitors. In fluorogenic assays, these two compounds and Clexane inhibited both physiological and recombinant furin in a dose-dependent way. In addition, these compounds increased physiological furin inhibition by CMK, showing an adjuvant effect. In conclusion, we identified Kukoamine A, Zeaxanthin, and Clexane as new furin inhibitors. In addition, these drugs were able to increase furin inhibition by CMK, so they could also increase its efficiency when avoiding S protein proteolysis, which is essential for SARS-CoV-2 cell infection.

Non-compliance with clinical guidelines increases the risk of complications after primary total hip and knee joint replacement surgery

BACKGROUND

Total hip and total knee replacement (THR/TKR) are common and effective surgeries to reduce the pain and disability associated with arthritis but are associated with small but significant risks of preventable complications such as surgical site infection (SSI) and venous-thrombo-embolism (VTE). This study aims to determine the degree to which hospital care was compliant with clinical guidelines for the prevention of SSI and VTE after THR/TKR; and whether non-compliant prophylaxis is associated with increased risk of complications.

METHODS AND FINDINGS

A prospective multi-centre cohort study was undertaken in consenting adults with osteoarthritis undergoing elective primary TKR/THR at one of 19 high-volume Australian public or private hospitals. Data were collected prior to surgery and for one-year post-surgery. Four adjusted logistic regression analyses were undertaken to explore associations between binary non-compliance and the risk of surgical complications: (1) composite (simultaneous) non-compliance with both (VTE and antibiotic) guidelines and composite complications [all-cause mortality, VTE, readmission/reoperation for joint-related reasons (one-year) and non-joint-related reasons (35-days)], (2) VTE non-compliance and VTE outcomes, (3) antibiotic non-compliance and any SSI, and (4) antibiotic non-compliance and deep SSI. Data were analysed for 1875 participants. Guideline non-compliance rates were high: 65% (VTE), 87% (antibiotics) and 95% (composite guideline). Composite non-compliance was not associated with composite complication (12.8% vs 8.3%, adjusted odds ratio [AOR] = 1.41, 95%CI 0.68-3.45, p = 0.40). Non-compliance with VTE guidelines was associated with VTE outcomes (5% vs 2.4%, AOR = 2.83, 95%CI 1.59-5.28,p < 0.001). Non-compliance with antibiotic guidelines was associated with any SSI (14.8% vs 6.1%, AOR = 1.98, 95%CI 1.17-3.62,p = 0.02) but not deep infection (3.7% vs 1.2%,AOR = 2.39, 95%CI 0.85-10.00, p = 0.15).

CONCLUSIONS

We found high rates of clinical variation and statistically significant associations between non-compliance with VTE and antibiotic guidelines and increased risk of VTE and SSI, respectively. Complications after THR/TKR surgery may be decreased by improving compliance with clinical guidelines.

The deep vein thrombosis of lower limb after total hip arthroplasty: what should we care

Background

Deep vein thrombosis (DVT) of lower limb is one of the common complications after total hip arthroplasty(THA), we aimed to evaluate the potential risk factors of DVT of lower limb in patients with THA, to provide insights into the management of THA.

Methods

Patients who underwent THA in our hospital from January 1, 2017 to November 30, 2020 were included. The personal characteristics and clinical data of DVT and no-DVT patients were compared and analyzed. Logistic regression analyses were perfomed to identify the potential risk factors of DVT in patients with THA.

Results

A total of 182 THA patients were included, the incidence of DVT of lower limb in patients with THA was 19.78 %. There were significant differences in the age, BMI, diabetes, number of replacement, duration of surgery, type of prosthesis and duration of days in bed between DVT and no-DVT patients(all P < 0.05). And there were no significant differences in the gender, hypertension, hyperlipidemia, preoperative D-dimer, type of anesthesia and anticoagulant drugs use(all P > 0.05). Logistic regression analysis indicated that age > 70y(OR4.406, 95 %CI1.744 ~ 6.134), BMI ≥ 28(OR2.275, 95 %CI1.181 ~ 4.531), diabetes(OR3.949, 95 %CI1.284 ~ 5.279), bilateral joint replacements(OR2.272, 95 %CI1.402 ~ 4.423), duration of surgery ≥ 120 min(OR3.081, 95 %CI1.293 ~ 5.308), cemented prosthesis(OR2.435, 95 %CI1.104 ~ 4.315), and duration of days in bed > 3 days(OR1.566, 95 %CI1.182 ~ 1.994) were the risk factors of DVT of lower limb in patients with THA.

Conclusions

DVT in the lower limb after THA is common, and its onset is affected by many factors. In clinical work, attention should be paid to identify the risk factors for DVT and targeted interventions are highlighted to prevent the postoperative DVT.

Efficacy and safety of aspirin and rivaroxaban for venous thromboembolism prophylaxis after total hip or knee arthroplasty: A protocol for meta-analysis

BACKGROUND

The purpose of this meta-analysis is to compare the efficacy and safety of aspirin and rivaroxaban in the prevention of venous thromboembolism (VTE) following either total knee arthroplasty or total hip arthroplasty.

METHODS

A comprehensive literature search of several electronic databases (PubMed, Embase, and Web of Science) was conducted to identify relevant studies. Outcomes of interest included VTE rate, deep vein thrombosis (DVT) rate, pulmonary embolism rate, major bleeding events, mortality rate, blood transfusion, and wound complication. Risk ratio (RR) with 95% confidence intervals (95%CIs) were calculated using a fixed-effects model or random-effects model.

RESULTS

A total of 8 studies with 97,677 patients met the inclusion criteria and were included in this meta-analysis. Compared with rivaroxaban, aspirin had a significantly higher incidence of DVT (RR = 1.48, 95%CI: 1.27, 1.72; P < .001), and decreased risk of blood transfusion (RR = 0.94, 95%CI: 0.93, 0.94; P < .001). However, there were no significant differences between the 2 drugs in terms of total VTE rate (RR = 1.39%, 95%CI: 0.94, 2.05; P = .101), pulmonary embolism rate (RR = 1.64, 95%CI: 0.92, 2.92; P = .094), mortality rate (RR = 1.13, 95%CI: 0.15, 8.27; P = .907), major bleeding (RR = 1.00, 95%CI: 0.44, 2.27; P = .995), and wound complication rate (RR = 0.37, 95%CI: 0.07, 1.87; P = .229).

CONCLUSION

Our results suggested that aspirin and rivaroxaban offered similar effect in the prevention of VTE after total knee arthroplasty or total hip arthroplasty. However, rivaroxaban seemed to have better effect than aspirin in reducing the risk of DVT, and aspirin was safer than rivaroxaban in decreasing the blood transfusion rate.

One Size Does Not Fit All: Venous Thromboembolism Prophylaxis in Colorectal Cancer

Background and Objectives

Venous thromboembolisms (VTEs) in patients who have undergone a colorectal cancer operation increases morbidity and mortality, lengthens recovery time, and are costly. The current common standard is a 28-day prophylactic regimen of 40 mg enoxaparin daily. This study aims to examine the variability in prophylaxis discharge prescriptions at one institution, report 30-day postoperative incidence of venous thromboembolisms and bleeding, and to offer a new protocol for VTE prophylaxis in postoperative patients.

Methods

This retrospective case series occurred at Abington-Jefferson Health Hospital in Abington, PA. The electronic medical record was searched for patients who underwent an operation for colorectal cancer from October 2019 to mid-March 2020 and all discharge prophylaxis regimens were recorded and patient demographics were analyzed. Outcomes were measured by rate of VTEs and postoperative complications such as bleeding, transfusions, re-admission, and intensive care admission in the 30-day postoperative period.

Results

Eighteen of 57 patients received a medication besides 40 mg of enoxaparin daily. These 18 patients were divided into six different sub-groups of various prophylaxis regimens. No patients developed a venous thromboembolism. Four of 18 patients experienced postoperative bleeding complications.

Conclusions

Patients with similar pre-operative comorbidities have various venous thromboembolism perioperative prophylaxis regimens prescribed. Despite prescription variations, VTE rates remain negligible. Patients with different comorbid conditions may require alterations to the traditionally prescribed 40 mg enoxaparin daily. Upon discharge, aspirin 81 mg with 40 mg of enoxaparin daily for high-risk patients shows benefits, but requires further investigation.

Aspirin for prevention of venous thromboembolism in recipients of major lower-limb orthopedic surgery: a systematic review of Level I evidence

INTRODUCTION

Major lower-limb orthopedic surgery recipients are at increased risk of venous thromboembolism (VTE). The optimal strategy for preventing VTE is a topic of ongoing debate. The use of aspirin has been implicated in reducing VTE events and is potentially advantageous compared to other agents in respect to cost, access, route of administration and reduced adverse effects such as bleeding.

EVIDENCE ACQUISITION

A systematic search for Level I evidence (systematic reviews and meta-analyses of randomised-controlled trials) was performed in April 2019 to evaluate the use of aspirin for primary and secondary VTE prophylaxis compared to alternative chemical and mechanical strategies. This search encompassed three electronic databases (Pubmed, Embase and the Cochrane Database of Systematic Reviews). All references of included studies were screened for additional studies. Data was compiled and compared to the recommendations and guidelines published by major institutions. Included studies were appraised with the aid of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist.

EVIDENCE SYNTHESIS

In total, 21 studies were included. Interventions and outcomes identified were heterogeneous across studies. Most statistical tests applied found no difference between aspirin and other interventions in regards to deep vein thrombosis, pulmonary embolism, bleeding and mortality outcomes.

CONCLUSIONS

Aspirin may be a viable alternative to established thromboprophylactic regimes for primary prevention of VTE, however in the setting of secondary prevention it is generally less efficacious. Future studies should have clearly identified and comparable outcome measures, with direct comparisons and assessment of intervention combination, dosing and treatment duration.