Aspirin Use for Venous Thromboembolism Prevention Is Safe and Effective in Overweight and Obese Patients Undergoing Revision Total Hip and Knee Arthroplasty

Hidden costs of first choice alternatives: A financial model of thromboprophylaxis and prosthetic joint infection prophylaxis in total knee arthroplasty

Background

Aspirin has been shown to be equally or more effective than factor Xa inhibitors for thromboprophylaxis following total knee arthroplasty (TKA). Cefazolin has been proven more effective than vancomycin in preventing prosthetic joint infection (PJI) after TKA. This study aimed to compare costs between different drug combinations for prevention of venous thromboembolism (VTE) and PJI following TKA, focusing on costs associated with PJI management.

Methods

We used published PJI rates for TKA patients treated with aspirin or factor Xa inhibitors for thromboprophylaxis, as well as for those who received prophylactic cefazolin or vancomycin. Unit prices for each drug and labor costs associated with vancomycin administration were obtained from our hospital's pharmacy service. The PJI cost model included the price of 2-stage septic TKA revision and national projections of future TKA volume.

Results

The least expensive average per-patient cost resulted from the combination of aspirin and cefazolin, equating to $521.19 given a 0.8 % PJI rate. The most expensive average per-patient cost was the combination of a factor Xa inhibitor and vancomycin, equaling $5,714.96 given a 1.8 % PJI rate. This extrapolates to an annual cost burden of $19.5 billion by 2040.

Conclusion

The average per-patient cost of using a combination of a factor Xa inhibitor and vancomycin is 711 % greater than the combination of aspirin and cefazolin. In this era of value-based care, aspirin and cefazolin should be considered gold standards for TKA thromboprophylaxis and PJI prophylaxis, as they reduce costs and improve patient outcomes.

Venous Thromboembolism Prophylaxis After Revision Hip Arthroplasty: A Multicenter Analysis of Anticoagulant Choice and Weight-Bearing Status

BACKGROUND

Aspirin (ASA) is a reliable prophylactic agent for venous thromboembolism (VTE) in revision total hip arthroplasty (THA). While several studies have compared ASA to other anticoagulants, to our knowledge, none have evaluated its effectiveness in patients who have restricted weight-bearing status (WBS). Limited mobilization after surgery increases the risk of VTE complications. This study aimed to assess the effects of WBS and anticoagulant choice on the rates of thrombotic and bleeding complications after revision of THA.

METHODS

We reviewed 3,000 revision THAs performed between 2019 and 2022 across four institutions. Data collected included demographic factors, comorbidities, indication for revision, WBS (weight bearing as tolerated [WBAT] versus non-WBAT), anticoagulant choice, and Caprini VTE risk assessment score. Incidences of VTE, deep vein thrombosis (DVT), pulmonary embolism (PE), drainage, hematoma, and periprosthetic joint infections were recorded. Multivariate logistic regression was used to evaluate the associations between postoperative thrombotic and bleeding events, prophylactic pharmacologic agents, and WBS.

RESULTS

The incidence of VTE, DVT, and PE was significantly lower in the ASA cohort compared to the non-ASA cohort (VTE: 1.2 versus 3.5%, P < 0.001; DVT: 0.9 versus 3.3%, P < 0.001; PE: 0.2 versus 0.9%, P < 0.001). Within the ASA cohort, the incidence of VTE (1.1 versus 1.1%), bleeding complications (4.5 versus 4.5%), and periprosthetic joint infection (5.1 versus 5.8%) were similar when stratified by WBAT and non-WBAT. Multivariate regression demonstrated that ASA prophylaxis decreased the likelihood of VTE compared to non-ASA (odds ratio: 0.35, confidence interval: 0.19 to 0.57, P < 0.001). Weight-bearing status was not a risk factor regarding VTE or bleeding events.

CONCLUSIONS

Aspirin is a safe and effective prophylactic option for VTE in revision THA, regardless of WBS. While the lower VTE incidence in the ASA group suggests efficacy, potential selection bias must be considered.

Update on antithrombotic therapy and body mass: a clinical consensus statement of the European Society of Cardiology Working Group on Cardiovascular Pharmacotherapy and the European Society of Cardiology Working Group on Thrombosis

Obesity and underweight are a growing health problem worldwide and a challenge for clinicians concerning antithrombotic therapy, due to the associated risks of thrombosis and/or bleeding. This clinical consensus statement updates a previous one published in 2018, by reviewing the most recent evidence on antithrombotic drugs based on body size categories according to the World Health Organization classification. The document focuses mostly on individuals at the extremes of body weight, i.e. underweight and moderate-to-morbid obesity, who require antithrombotic drugs, according to current guidelines, for the treatment or prevention of cardiovascular diseases or venous thromboembolism. Managing antithrombotic therapy or thromboprophylaxis in these individuals is challenging, due to profound changes in body composition, metabolism and organ function, and altered drug pharmacokinetics and pharmacodynamics, as well as weak or no evidence from clinical trials. The document also includes artificial intelligence simulations derived from in silico pharmacokinetic/pharmacodynamic models, which can mimic the pharmacokinetic changes and help identify optimal regimens of antithrombotic drugs for severely underweight or severely obese individuals. Further, bariatric surgery in morbidly obese subjects is frequently performed worldwide. Bariatric surgery causes specific and additional changes in metabolism and gastrointestinal anatomy, depending on the type of the procedure, which can also impact the pharmacokinetics of antithrombotic drugs and their management. Based on existing literature, the document provides consensus statements on optimizing antithrombotic drug management for underweight and all classes of obese patients, while highlighting the current gaps in knowledge in these complex clinical settings, which require personalized medicine and precision pharmacology.

The Use of Aspirin for Venous Thromboembolism Prophylaxis in Patients Who Have Morbid Obesity Undergoing Primary and Revision Total Joint Arthroplasty

BACKGROUND

Venous thromboembolism (VTE) poses a major clinical concern due to its life-threatening nature, and obese and morbidly obese patients are thought to be at an increased risk for VTE. The aims of this study were twofold; first, to explore VTE rates in patients who have a body mass index (BMI) > 40 undergoing primary and revision total joint arthroplasty, and second, to investigate aspirin (ASA) efficacy and safety.

METHODS

We identified all patients (n = 4,672) who had a BMI > 40 who underwent primary and revision total joint arthroplasty from 2016 to 2022 at a single academic tertiary care center. Patients were stratified by BMI groups: 40 to 44.9 (n = 3,462), 45 to 49.9 (n = 935), and 50+ (n = 275). The primary outcome was any VTE event within 90 days postoperatively. The secondary outcome consisted of wound complications within 90 days postoperatively.

RESULTS

The total VTE rate was 0.4% (n = 21) and did not differ statistically between the BMI groups (0.4 versus 0.4 versus 0.7%, P = .669). The VTEs consisted of 6 deep venous thromboses (DVTs), 14 pulmonary embolisms, and one concomitant deep venous thrombosis and pulmonary embolism. The VTE rates were not statistically different between patients who received aspirin 325 mg 0.5% (n = 9), aspirin 81 mg 0.2% (n = 1), aspirin + anticoagulant (AC) 0.5% (n = 6), and AC alone 0.4% (n = 5) (P = .954). In addition, wound complications did not differ significantly between patients who received ASA 325 mg, ASA 81mg, ASA + AC, or AC alone (1.6 versus 1.0 versus 1.8 versus 1.1%, P = .351).

CONCLUSIONS

The use of aspirin 325 and 81 mg was found to have similar VTE rates as aspirin + ACs and ACs alone, with no significant increase in wound complications. In patients who have a BMI > 40, the use of aspirin is a safe option for VTE prophylaxis and should be prescribed in the context of the patient who has other risk factors for VTE.

Aspirin versus low-molecular-weight heparin for thromboprophylaxis after orthopaedic surgery: a systematic review and meta-analysis

The article aimed to compare the efficiency and safety of aspirin with low-molecular-weight heparin (LMWH) for thromboprophylaxis in orthopaedic surgery patients. According to the inclusion and exclusion criteria, PubMed, Embase and Cochrane Library database were searched for studies comparing aspirin and LMWH in venous thromboembolism (VTE) prophylaxis until 25 April 2023. The outcome measures included deep venous thrombosis(DVT)/Pulmonary embolism(PE) events, major bleeding events, wound complications, wound infection and death. Six studies met the requirements of our meta-analysis, including 12 470 patients in the aspirin group and 10 857 patients in the LMWH group. The meta-analysis showed that results showed that LMWH was superior to aspirin in preventing VTE events (odds ratio (OR) 1.44, 95% CI 1.24-1.68, P  < 0.00001), whereas there was no significant difference between them in bleeding events (OR 0.95, 95% CI 0.86-1.05, P  = 0.33), wound complication (OR 0.58, 95% CI 0.28-1.17, P  = 0.13), wound infection (OR 1.12, 95% CI 0.86-1.47, P  = 0.39) and mortality (OR 1.04, 95% CI 0.70-1.55, P  = 0.83). In addition, subgroup analysis showed that compared with aspirin, LMWH was more likely to reduce the incidence of DVT events in orthopaedic surgery patients (OR 1.59, 95% CI 1.33-1.91, P  < 0.00001), whereas there was no advantage in reducing the incidence of PE events (OR 1.22, 95% CI 0.62-2.40, P  = 0.56). Despite the similar safety profiles, this meta-analysis showed that LMWH was significantly superior to aspirin in thromboprophylaxis after orthopaedic surgery. LMWH was still the first-line drug for thrombosis prevention in patients who underwent major orthopaedic surgeries.

The Financial Burden of Aspirin versus Oral Factor Xa Inhibitors for Thromboprophylaxis Following Total Knee Arthroplasty

BACKGROUND

Aspirin and oral factor Xa inhibitor thromboprophylaxis regimens are associated with similarly low rates of venous thromboembolism following total knee arthroplasty (TKA). However, the rate of prosthetic joint infection (PJI) is lower with aspirin use. This study aimed to compare the cost differential between aspirin and factor Xa inhibitor thromboprophylaxis with respect to PJI management.

METHODS

We used previously published rates of PJI following aspirin and factor Xa inhibitor thromboprophylaxis in primary TKA patients at a single, large institution. Prices for individual drugs were obtained from our hospital's pharmacy service. The cost of PJI included that of 2-stage septic revision, with or without the cost of 1-year follow-up. National data were obtained to determine annual projected TKA volume.

RESULTS

The per-patient costs associated with a 28-day course of aspirin versus factor Xa inhibitor thromboprophylaxis were $17.36 and $3,784.20, respectively. Including cost of follow-up, per-patient costs for a 28-day course of aspirin versus factor Xa inhibitors increased to $73,358.76 and $77,125.60, respectively. The weighted average per-patient costs for a 28-day course were $237.38 and $4,370.93, respectively. The annual cost difference could amount to over $14.1 billion in the United States by 2040.

CONCLUSIONS

The per-patient cost associated with factor Xa inhibitor thromboprophylaxis is as much as 1,980.6% higher than that of an aspirin regimen due to increased costs of primary treatment, differential PJI rates, and high costs of management. In an era of value-based care, the use of aspirin is associated with major cost advantages.

Trends in deep vein thrombosis prophylaxis after total hip arthroplasty: 2016 to 2021

Introduction

Venous thromboembolism (VTE) has long been acknowledged as a potential complication of total hip arthroplasty (THA) contributing to heightened patient morbidity, mortality, and substantial healthcare costs. We aimed to: 1) assess trends in VTE prophylaxis utilization between 2016 and 2021; 2) determine the incidence of postoperative VTE and transfusions; and 3) identify independent risk factors for 90-day VTE and transfusion risks following THA in relation to the use of aspirin, dabigatran, enoxaparin, rivaroxaban, and warfarin.

Methods

A national, all-payer database was queried from January 1, 2016 and December 31, 2022. Use trends for aspirin, enoxaparin, rivaroxaban, dabigatran, and warfarin as thromboprophylaxis following THA was assessed. Incidence of ninety-day postoperative outcomes assessed included rates of 90-day postoperative VTE and transfusion.

Results

From 2016 to 2021, aspirin (n = 36,346) was the most used agent for VTE prophylaxis after THA, followed by dabigatran (n = 13,065), rivaroxaban (n = 11,790), enoxaparin (n = 11,380), and warfarin (n = 6326). Independent risk factors for 90-day VTE included CKD, COPD, CHF, obesity, dabigatran, enoxaparin, rivaroxaban, and warfarin (all p < 0.05).

Conclusion

Aspirin was used with increasing frequency and demonstrated lower rates of VTE and transfusion following THA, compared to dabigatran, enoxaparin, rivaroxaban, and warfarin. These findings seem to indicate that the increasing use of aspirin in VTE prophylaxis has been accomplished in appropriately selected patients.

Venous Thromboembolism Chemoprophylaxis in Knee Arthroscopy: A Break-Even Analysis of Cost

BACKGROUND

Symptomatic venous thromboembolism (VTE) is a serious and costly complication after knee arthroscopy. There continues to be debate regarding the use of VTE prophylaxis after knee arthroscopy, and minimal research has explored its cost-effectiveness.

HYPOTHESIS

Both aspirin and enoxaparin would be cost-effective in preventing symptomatic VTE.

STUDY DESIGN

Economic and decision analysis; Level of evidence, 3.

METHODS

The literature was searched and the TriNetX research database was queried to determine a range of initial rates of VTE. An open-access retail database was used to determine the mean retail price for aspirin (325 mg) and enoxaparin (30 mg and 40 mg). Our institutional records were used to determine the cost of treating VTE. A "break-even" analysis was then performed to determine the absolute risk reduction necessary to make these drugs cost-effective. This value was then used to calculate the number of patients who would need to be treated (NNT) to prevent a single VTE while still breaking even on cost.

RESULTS

The cost of treating VTE was $9407 (US Dollars). Aspirin (325 mg), enoxaparin (30 mg), and enoxaparin (40 mg) were found to cost $1.86, $188.72, and $99.99, respectively. The low, TriNetX, and high rates of VTE were 0.34%, 0.86%, and 10.9%, respectively. Aspirin was cost-effective at all 3 rates if the initial rate decreased by 0.02% (NNT = 5058). Both formulations of enoxaparin were cost-effective at the high initial rate if they decreased by 2.01% (NNT = 50) and 1.06% (NNT = 94), respectively. However, at the low and TriNetX rates, the 2 doses of enoxaparin were not cost-effective because their final break-even rate exceeded the initial VTE rate.

CONCLUSION

Aspirin and, in some cases, enoxaparin are cost-effective treatments for VTE prophylaxis after knee arthroscopy.

Obesity and the Risk of Venous Thromboembolism after Major Lower Limb Orthopaedic Surgery: A Literature Review

The risk of venous thromboembolism following total joint arthroplasty is significantly greater than those of other types of elective orthopaedic procedures. This risk is increased in obesity due to the associated prothrombotic physiological and hematological changes that predispose to embolic events. The prevalence of obesity is increasing in the aging population, which contributes to a further increase in the risk of postoperative thrombosis in the older patients. There is a lack of clear evidence regarding dosing information for thromboprophylaxis medications in patients with obesity. As a result, the currently available thromboprophylaxis guidelines do not provide specific recommendations for this group. Suboptimal dosing regimens for these medications can place these patients at a risk of bleeding or clotting complications postsurgery. Hence any increase in dosage may require intensive surveillance for the residual anticoagulant effects and careful balancing of risks and benefits on an individual basis. Our review discusses the basis for increased thrombotic risk in obesity, the evidence supporting dosage recommendations, and the implications of the current guidelines for pharmacological thromboprophylaxis in patients with obesity undergoing lower limb arthroplasty.

Effect of body mass index on symptomatic venous thromboembolism and prosthesis revision risk after total knee arthroplasty: a long-term study from China

OBJECTIVE

To investigate the effect of body mass index (BMI) on the risk of symptomatic VTE and prosthesis revision after total knee arthroplasty (TKA).

METHODS

Seven thousand one hundred eighty-two patients with primary unilateral TKA treated in our hospital from 2011 to 2020 were divided into four groups according to BMI: BMI < 25 kg/m², BMI 25 kg/m²-29.9 kg/m², BMI 30 kg/m²-34.9 kg/m² and BMI ≥ 35 kg/m². Incidence, Odds ratio and Kaplan-Meier survival analysis were used to evaluate the effects of BMI on symptomatic VTE and prosthesis revision risk after TKA.

RESULTS

The incidence of VTE after TKA was 8.9‰(64/7182). There was no significant difference in the incidence of VTE among different BMI groups(P = 0.452). Deep vein thrombosis mainly occurred in the distal lower extremities, especially in intermuscular veins. Revision rate of prosthesis after TKA was 6.4‰(46/7182). There was no significant difference in revision rate among different BMI groups(P = 0.718). In the univariate analysis of TKA, compared with patients with normal BMI, the risk of postoperative VTE and prosthesis revision in patients with overweight, obesity class I and obesity class II did not increase. Higher prosthesis revision rate and lower prosthesis survival rate were observed in BMI ≥ 35 kg/m² group, although the difference was not statistically significant.

CONCLUSIONS

Through such a retrospective large sample data of long-term follow-up, we believe that the higher BMI was not associated with the increased risk of symptomatic VTE and prosthesis revision after TKA. When TKA was used for appropriate indications, high BMI should not be considered as a contraindication.

Morbidly Obese Patients Undergoing Primary Total Joint Arthroplasty May Experience Higher Rates of Venous Thromboembolism When Prescribed Direct Oral Anticoagulants vs Aspirin

BACKGROUND

Morbidly obese (body mass index [BMI] >40 kg/m²) patients undergoing total joint arthroplasty (TJA) are at high risk for postoperative venous thromboembolism (VTE); however, there is debate surrounding the optimal pharmacologic agent for prevention of VTE after TJA in this patient subset. Current guidelines recommend against direct-acting oral anticoagulants (DOACs) in patients of BMI >40 kg/m² due to low quality evidence justifying their use. We evaluated whether patients of BMI >40 kg/m² undergoing primary unilateral TJA would have increased risk of postoperative VTE if prescribed DOACs compared to non-DOAC agents such as aspirin.

METHODS

This retrospective study analyzed 897 patients of BMI >40 kg/m² undergoing primary unilateral TJA. Demographic and comorbidity-related variables were collected. The association between postoperative VTE and prophylactic pharmacologic agent prescribed was evaluated by multivariate logistic regression.

RESULTS

After controlling for comorbidities, we found that the sole use of DOACs, specifically apixaban, for VTE prophylaxis was associated with an increased risk of developing VTE compared to prophylaxis with aspirin alone in patients of BMI >40 kg/m² (odds ratio 2.962, P = .016). Regardless of VTE prophylactic agent, patients with BMI >40 kg/m² undergoing TKA had at least 4.5-fold increased odds of developing VTE compared to patients undergoing THA (OR 4.830, P = .019).

CONCLUSION

In our retrospective study of a large sample size of patients with BMI >40 kg/m², we found that the use of DOACs, specifically apixaban, for VTE prophylaxis following TJA was associated with increased odds of a VTE complication compared to the use of aspirin alone.

Versatility and accuracy of a novel image-free robotic-assisted system for total knee arthroplasty

INTRODUCTION

Technological advances alongside increased demand for knee replacement surgery have led to the development of a novel image-free bed rail-mounted robotic-assisted system for total knee arthroplasty (TKA). The device is capable of real-time tracking to accommodate for leg motion during bone resection allowing for precise control and positioning of the bone saw in the planned resection plane. The purpose of this study is to discuss the versatility and accuracy of this novel image-free robotic-assisted technology in TKA.

METHODS AND MATERIALS

The novel robotic-assisted system underwent a stepwise assessment to verify its versatility and accuracy. First, functional accuracy was bench tested to evaluate predetermined surgical plans independent of user variability and anatomic variability compared to conventional instrumentation. This was followed by assessments utilizing cadaveric specimens for resection accuracy, implant positioning, and soft tissue involvement.

RESULTS

Test bench accuracy revealed overall pooled linear positional accuracy of 0.326 ± 0.249 mm and pooled angular positional accuracy of 0.365 ± 0.611°. Resection errors for both robotic and conventional cohorts ranged between 0.6° and 1.9°. Concerning coronal alignment, 33/40 robotic specimen were within ± 1° and 38/40 within ± 3° of the femoral varus-valgus target, compared with 17/40 and 37/40 with conventional instrumentation, respectively. Twenty-four of the 40 robotic specimens were within ± 1° and 40/40 within ± 3° of the tibial varus-valgus target compared with 15/40 and 32/40 with conventional instrumentation, respectively. Soft tissue structures were uncompromised in all robotic-assisted cases. Conventional instruments revealed two cases of partial cleavage of the posterior cruciate ligament and two instances of a compromised posterior medial capsule. There were no significant differences between the two techniques concerning the samples that were uncompromised and fully functional (40/40 vs. 38/40, p = 0.49).

CONCLUSION

The novel image-free robotic-assisted surgical system demonstrates excellent benchtop accuracy to aid bony resection in cadaveric specimens. It offers notable improvement in coronal implant alignment compared to conventional instrumentation.

Postoperative venous thromboembolism event increases risk of readmissions and reoperation following total joint arthroplasty: a propensity-matched cohort study

PURPOSE

The clinical impact of postoperative venous thromboembolism (VTE) following total joint arthroplasty (TJA) remains unclear. In this study, we evaluate the effect of VTE following TJA on postoperative outcomes including discharge disposition, readmission rates, and revision rates.

METHODS

We retrospectively reviewed all patients over the age of 18 who underwent primary, elective THA or TKA between 2013 and 2020. Patients were stratified into two cohorts based on whether or not they had a VTE following their procedure. Baseline patient demographics and clinical outcomes such as readmissions and revisions were collected. Propensity score matching was performed to limit significant demographic differences, while independent sample t-tests and Pearson's chi-squared test were used to compare outcomes of interest between the groups.

RESULTS

After propensity score matching, there were 109 patients in each cohort, representing a total of 218 patients for the matched comparison. Prior to matching, the VTE cohort was noted to have a significantly higher BMI than the non-VTE cohort (32.22 ± 6.27 vs 30.93 ± 32.04 kg/m², p = 0.032). All other patient demographics were similar. Compared to the non-VTE cohort, the VTE cohort was less likely to be discharged home (66.1% vs 80.7%; p = 0.021), had a higher rate of 90-day all-cause readmissions (27.5% vs 9.2%, p = 0.001), and a higher two-year revision rate (11.0% vs 0.9%, p = 0.003).

CONCLUSION

Patients with postoperative VTE were less likely to be discharged home and had higher 90-day readmission and two-year revision rates. Therefore, mitigating perioperative risk factors, initiating appropriate long-term anticoagulation, and maintaining close follow-up for patients with postoperative VTE may play significant roles in decreasing hospital costs and the economic burden to the healthcare system.

LEVEL OF EVIDENCE III

Retrospective Cohort Study.

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.