Thromboprophylaxis in hip arthroplasty. New frontiers and future strategy

Thromboprophylaxis in primary shoulder arthroplasty does not seem to prevent death: a report from the Norwegian Arthroplasty Register 2005-2018

Background and purpose - There is still no consensus on whether to use thromboprophylaxis as a standard treatment in shoulder replacement surgery. We investigated the use of thromboprophylaxis reported to the Norwegian Arthroplasty Register (NAR). The primary endpoint was early mortality after primary shoulder arthroplasty with and without thromboprophylaxis. Secondary endpoints included revisions within 1 year and intraoperative complications.Patients and methods - This observational study included 6,123 primary shoulder arthroplasties in 5,624 patients reported to the NAR from 2005 to 2018. Cox regression analyses including robust variance analysis were performed with adjustments for age, sex, ASA score, diagnosis, type of implant, fixation, duration of surgery, and year of primary surgery. An instrumental variable Cox regression was performed to estimate the causal effect of thromboprophylaxis.Results - Thromboprophylaxis was used in 4,089 out of 6,123 shoulder arthroplasties. 90-day mortality was similar between the thromboprophylaxis and no thromboprophylaxis groups (hazard ratio (HR) = 1.1, 95% CI 0.6-2.4). High age (> 75), high ASA class (≥ 3), and fracture diagnosis increased postoperative mortality. No statistically significant difference in the risk of revision within 1 year could be found (HR = 0.6, CI 0.3-1.2). The proportion of intraoperative bleeding was similar in the 2 groups (0.2%, 0.3%).Interpretation - We had no information on cause of death and relation to thromboembolic events. However, no association of reduced mortality with use of thromboprophylaxis was found. Based on our findings routine use of thromboprophylaxis in shoulder arthroplasty can be questioned.

Thromboembolic risk assessment and the efficacy of enoxaparin prophylaxis in excisional body contouring surgery

BACKGROUND

There is a paucity of evidence within the plastic surgery literature concerning risk stratification and management of patients with respect to thromboembolic disease. A retrospective chart review was conducted to examine whether the Davison-Caprini risk-assessment model could stratify patients undergoing excisional body contouring surgery, allowing prophylaxis to be managed in an evidence-based manner.

METHODS

Three hundred sixty excisional body contouring patients at the University of Texas Southwestern Medical Center in Dallas, Texas, under the senior authors' (J.M.K. and R.J.R.) care were reviewed. Patients were stratified into groups according to the risk-assessment model and into groups based on procedure. Patient characteristics were investigated for their effects on thromboembolic risk. Complications of enoxaparin administration were analyzed. The data were analyzed using appropriate statistical procedures.

RESULTS

The highest risk patients had a significantly increased rate of venous thromboembolism when compared with lower risk patients. Body mass index greater than 30 and hormone therapy use were associated with a significantly increased venous thromboembolism rate. Enoxaparin administration was associated with a statistically significant decrease in deep venous thrombosis in circumferential abdominoplasty patients. Enoxaparin administration was associated with higher bleeding rates.

CONCLUSIONS

Low-molecular-weight heparin may affect the incidence of postoperative thrombotic complications in some surgical populations. In this study, patients who scored greater than four risk factors were at significant risk for venous thromboembolism. Enoxaparin significantly decreased deep venous thrombosis risk in patients undergoing circumferential abdominoplasty. This demonstrates the need for a multicenter, prospective, randomized study to examine various thromboembolic therapies and associated possible complications in these patients.

Malaysian orthopaedic surgeons' approach to venous thromboembolic disease prophylaxis: attitudes and practice

PURPOSE

To survey Malaysian orthopaedic surgeons' attitudes to and use of venous thromboembolic disease prophylaxis.

METHODS

A total of 144 orthopaedic surgeons from various governmental and private institutions responded to a questionnaire.

RESULTS

Only slightly more than half of these surgeons considered venous thromboembolic disease as common a problem in Malaysia as in western countries. The majority of surgeons (91.0%) reported using prophylaxis selectively for patients based on various indicators such as risk grading of surgery, obesity, and malignancy etc. Bleeding tendencies were cited as the greatest fear against the use of pharmacological prophylaxis. Low-molecular-weight heparin appeared to be the most commonly used pharmacological prophylaxis, used either singly or in combination with other forms of prophylaxis. The majority of surgeons employed prophylaxis until their patients were mobile.

CONCLUSION

There should be greater awareness among surgeons in Malaysia of the need for protection against venous thromboembolic disease. Current practice needs to be reviewed and further recommendations made for existing protocols.

Measuring the outcomes and pharmacoeconomic consequences of venous thromboembolism prophylaxis in major orthopaedic surgery

Patients who have undergone orthopaedic surgery represent a high-risk group for venous thromboembolism (VTE). Despite the routine prophylactic use of antithrombotic agents, patients still experience thrombotic events that can result in mortality and acute morbidity and, in significant numbers of patients, may lead to long-term consequences such as the post-thrombotic syndrome. Increasingly, initial VTE events occur after hospital discharge since the length of stay in hospital after major orthopaedic surgery has decreased in many countries. There is a need for further improvement in the prevention of VTE. As well as undergoing extensive safety and efficacy studies for registration purposes, new prophylactic strategies need to be evaluated from a pharmacoeconomic perspective to help guide their introduction into routine clinical practice. Over the past 15 years a number of pharmacoeconomic evaluation studies of VTE prophylaxis have been carried out in orthopaedic patients, most of which evaluated short-term clinical endpoints. During the same period, improvements in our understanding of the natural history of VTE as well as the emergence of new treatments have led to changes in the management of patients with, or at risk of, VTE. The aim of this paper was to address how best to conduct pharmacoeconomic analyses of new antithrombotic agents in light of changes in practice patterns for orthopaedic patients and greater understanding of the disease process. We put forward recommendations for relevant outcome measures, timeframes, endpoints and epidemiologic data sources. We also suggest a structure for a pharmacoeconomic model. In this model, the outcomes and costs of VTE-related care during both the acute and chronic phases of the disease are incorporated. Symptomatic deep vein thrombosis and pulmonary embolism, recurrent VTE, post-thrombotic syndrome, major hemorrhage and all-cause death are included. We also recommend that the relevance of quality-adjusted survival is investigated, and that economic appraisals are presented in both cost-consequence and budget-impact approaches. These recommendations are based on extensive examination of recent advances in the management of VTE combined with a greater understanding of its natural history.

Early postoperative mortality after 67,548 total hip replacements: causes of death and thromboprophylaxis in 68 hospitals in Norway from 1987 to 1999

Patients in the Norwegian Arthroplasty Register with a total hip replacement (THR) have a lower long-term mortality than the age- and gender-matched Norwegian population. We analyzed the early postoperative mortality after 67,548 THR operations in 68 hospitals reported to the Norwegian Arthroplasty Register between 1987 and 1999. Data on deaths and causes of death were obtained from from Statistics Norway, and on thromboprophylaxis from a separate questionnaire sent to all hospitals. During the years 1987-2000 the 68 hospitals reported use of 6 thromboprophylaxis drugs and 24 different combinations of drugs and stockings. In 1988, only 3 of 29 hospitals reported use of low molecular weight heparin (LMWH), but in 1999, 67 of the 68 hospitals used LMWH. In the first postoperative week, the daily mortality was about 2.5 deaths per 10,000 THR patients. By the 70th postoperative day, the daily mortality had declined to about 0.57 deaths per 10,000 patients. The daily mortality of the age- and gender-matched Norwegian population was 0.95 deaths per 10,000 individuals. Early postoperative mortality increased with age, was higher in men than women, and was usually due to vascular disease. We found only a slight reduction in the 60-day postoperative mortality during the period 1987-1999. All underlying diagnoses for a prosthesis operation had a higher 60-day postoperative mortality than primary osteoarthrosis.

Platelet release of transforming growth factor-beta and beta-thromboglobulin after in vitro contact with acrylic bone cements

Three methacrylate-based bone cements used for the fixation of joint prostheses were evaluated: Sulfix-60 (Sulzer Orthopedic Inc., Baar, Switzerland). CMW1 (DePuy International Ltd., England). and CMW2 (DePuy International Ltd., England). The cements after polymerization were put in contact in vitro with platelet-rich plasma. Plasma, in contact only with siliconized glass, was used as a negative control. After contact, platelet number. beta-thromboglobulin (beta-TG), and transforming growth factor-beta1 (TGF-beta1) were determined. The Student's paired t test showed that the ccments induced no significant modifications of platelet number. CMWI and Sulfix-60 determined a significant increase in beta-TG compared with the negative control. All cements determined a significant increase in TGF-beta1. Significant differences were also seen in the levels of beta-TG and TGF-beta1 between cements with a content of benzoyl peroxide < 1 (Sulfix-60) and those with a content > 1 (CMW1 and CMW2). The cement with zirconium dioxide (Sulfix-60) produced higher levels of beta-TG and TGF-beta1, compared to those with barium sulphate (CMW1 and CMW2). In conclusion, all the cements induced the secretion of TGF-beta1 CMW1 and Sulfix-60 determined also a significant release of beta-TG. Platelet activation induced by the cements from one side could contribute to the pathogenesis of deep venous thrombosis, that often occurs after prosthetic implant and is caused also by other factors, including surgical trauma and venous stasis. From the other side, activated platelets can release growth factors favoring bone formation.

Prophylaxis against fat and bone-marrow embolism during total hip arthroplasty reduces the incidence of postoperative deep-vein thrombosis: a controlled, randomized clinical trial

BACKGROUND

Clinical and experimental studies have suggested that the maximum risk of thrombogenesis occurs during, rather than after, total hip arthroplasty. With use of conventional cementing techniques, insertion of a femoral component results in marrow embolization of tissue thromboplastin into the veins of the proximal part of the femur, leading to activation of the clotting cascade and thrombogenesis. We hypothesized that an operative technique designed for the prevention of fat and bone-marrow embolism can also reduce the incidence of postoperative deep-vein thrombosis and pulmonary embolism.

METHODS

A total of 130 consecutive patients with osteoarthritis who were to have a primary total hip arthroplasty were randomly assigned to one of two groups. One group consisted of sixty-five patients (sixty-five hips) who had the femoral component inserted with our standard cementing technique without use of a bone vacuum, and the other group included sixty-five patients (sixty-five hips) who had the femoral component cemented with use of a bone-vacuum technique. In the hips managed with the bone vacuum, suction (-800 mbar) was applied to a drainage cannula placed along the linea aspera of the femur in order to prevent an increase in intramedullary pressure during the insertion of the stem. We measured the incidence of intraoperative fat and bone-marrow embolism with use of echocardiography and a transesophageal probe and the incidence of deep-vein thrombosis with use of serial duplex ultrasonography on the day before the operation and on postoperative days 4, 14, and 45. All patients were managed with prolonged pharmacological prophylaxis (low-molecular-weight heparin) against deep-vein thrombosis.

RESULTS

The control group had significantly more severe and prolonged echocardiographic embolic events than did the group managed with the bone-vacuum technique (p < 0.05). A cascade of fine echogenic particles or embolic masses with a diameter of < or =5 mm was observed during the insertion of the stem in fifty-nine hips (91%) in which our standard cementing technique was used and in ten hips (15%) in which the bone-vacuum cementing technique was used. Deep-vein thrombosis was detected on postoperative day 4 in twelve patients (18%) in the control group and in two patients (3%) in the group managed with the bone-vacuum technique; the difference was significant (p < 0.05).

CONCLUSIONS

Intraoperative prophylaxis against fat and bone-marrow embolism during total hip arthroplasty with cement can reduce the incidence of postoperative deep-vein thrombosis. We now use the bone-vacuum technique routinely in all total hip arthroplasties performed with cement.

Dalteparin vs. enoxaparin as prophylaxis for deep-vein thrombosis after total hip or knee arthroplasty: a retrospective analysis

OBJECTIVE

To assess the clinical and economic consequences of a formulary switch from enoxaparin to dalteparin as first-line prophylaxis for deep-vein thrombosis in patients undergoing inpatient rehabilitation after total hip arthroplasty or total knee arthroplasty.

DESIGN

Retrospective cohort study.

RESULTS

There were 461 patients eligible for the study. The age-adjusted risk of a deep-vein thrombosis event confirmed by duplex ultrasonography among patients treated with dalteparin was substantially lower than among patients treated with enoxaparin, whereas the age-adjusted risk of a bleeding event in the dalteparin group was also lower than that in the enoxaparin group. Adjusted per capita costs of deep-vein thrombosis prophylaxis during the rehabilitation stay were $129 lower among subjects treated with dalteparin.

CONCLUSION

The switch to dalteparin as a first-line therapy for deep-vein thrombosis prophylaxis in the rehabilitation period after total hip arthroplasty or total knee arthroplasty has led to substantial cost savings for Kessler Institute without compromising patient care.

No effect of methacrylate-based bone cement CMW 1 on the plasmatic phase of coagulation, red blood cells and endothelial cells in vitro

The compatibility of a methacrylate-based bone cement (CMW 1, DePuy International Ltd, England) used for the fixation of joint prostheses was evaluated on plasma, an erythrocyte suspension and cultured human endothelial cells. The extract of the cement was tested, following 1 hour and 7 days of curing. After the contact in vitro of the extract with plasma, activated partial thromboplastin time, antithrombin III, thrombin-antithrombin complexes and fibrin degradation products were assayed. Hemolytic activity was tested by adding the cement extracts to a suspension of erythrocytes. After 4 hours of incubation at 37 degrees C, the hemoglobin concentration was determined on the supernatants by the colorimetric method. The effect of the cement on tissue factor and thrombomodulin production was evaluated on human umbilical vein endothelial cell cultures. Tissue factor was determined in cell lysates by enzyme immunoassay, following 4 hours' incubation of cultures with the cement extract. Thrombomodulin was assayed in cell lysates by enzyme immuno assay, after 24 hours' incubation with the cement extract. The response to all trans-retinoic acid (ATRA) was tested. The cement caused no significant modifications of the coagulation tests, had no hemolytic activity, did not determine tissue factor production and did not modify thrombomodulin, compared to the negative control. The response to stimulation with ATRA was similar to that of the negative control. We conclude that the cement extract does not affect the plasmatic phase of coagulation, has no effect on erythrocytes, does not induce the expression of procoagulant activity by endothelial cells and does not impair their antithrombotic property, within the limits of the tests performed.