Rate Of Postoperative Venous Thromboembolism Research Articles

The Rate and Mortality of Postoperative Venous Thromboembolism of Moderate Risk Surgery in Asian Patients without Thrombo‐prophylaxis: Systematic Review with Meta‐analysis

The general gynecologic and neurologic surgeries are regard as carrying moderate risk for postoperative venous thromboembolism (VTE). This review analyzed the postoperative VTE rate of these surgeries in Asia. Inclusion criteria were: prospective study; deep vein thrombosis (DVT) diagnosed by venography, ultrasonography, or radionucleotide scan; and no thromboprophylaxis. The pooled proportion was back calculated from Freeman-Tukey variant transformation, using a random effect model. Medline, EMBASE, Cochrane Library, and KoreaMed were searched. Fourteen studies (total population of 1,625) published from 1974 to 2008 were included. In general surgery, the pooled rate of all-sites proximal, isolated distal DVT was 13.4, 2.1, and 11.8 % (radionucleotide scan). The cancer patients carried a higher all-sites DVT rate (19.7 % radionucleotide scan and 17.4 % ultrasound). Gynecologic and neurologic surgery had 3.1 % (ultrasound) and 3.8 % (radionucleotide scan) all-sites DVT rate. For general, gynecologic, and neurologic patients, the pooled rates of symptomatic DVT were 1.5, 0.2, and 1.0 % respectively. The pooled rate of symptomatic pulmonary embolism (PE) was 0.4 % for general surgery. No patients died from PE (pooled rate 0.2 %); however, a single PE death was reported in the excluded study. Postoperative symptomatic VTE was relatively low in Asia. Further study is required to stratify VTE risk and the need for thromboprophylaxis in individual patients.

Venous Thromboembolism (VTE) Rates Following the Implementation of Extended Duration Prophylaxis for Patients Undergoing Surgery for Gynecologic Malignancies

The most common preventable cause of hospital death in the United States is venous thromboembolism (VTE). The risk of VTE among women undergoing major surgery for gynecologic cancer can be substantially reduced by use of postoperative VTE prophylaxis consisting of subcutaneous unfractionated heparin or low-molecular-weight heparin (LMWH) and mechanical prophylaxis. Evidence-based guidelines from several national organizations recommend that patients undergoing abdominal or pelvic surgery for malignancy receive this VTE prophylaxis regimen for up to 28 days postoperatively. Despite these recommendations, VTE prophylaxis is widely underused in this patient population. Poor compliance with the VTE prevention guidelines at the MD Anderson Cancer Center in Houston resulted in a higher than expected postoperative VTE rate among gynecologic-oncology patients. In 2009, standardized extended VTE prophylaxis practice guidelines were initiated at this institution for all patients undergoing laparotomy for gynecologic cancer to improve guideline compliance and reduce postoperative VTE rates. The aim of this study was to compare the incidence of VTE before and after the implementation of the standardized prophylaxis guidelines in women undergoing laparotomy for gynecologic cancer. Patients were started on LMWH within 24 hours of surgery, and it was continued for a total of 28 days postoperatively. The incidence of VTE diagnosed within 30 and 90 days of surgery in a postimplementation guideline group (extended-duration LMWH, n = 334) was compared with a preguideline historical group (no extended-duration LMWH, n = 300). The incidence of VTE diagnosed within 30 days of surgery was reduced by 78% in the postguideline group compared with the preguideline group (2.7% vs 0.6%, respectively; P = 0.040). However, the effect was not sustained when the preguideline and postguideline implementation groups were compared for VTE diagnosed within 90 days of surgery (3.7% vs 3.0%, respectively; P = 0.619). The median time between surgery and VTE diagnosis was significantly longer following implementation of the guidelines (57 vs 12 days, respectively; P = 0.012). These data show significant reduction of VTE rates in a cohort of women undergoing laparotomy for gynecologic malignancy who received extended-duration LMWH compared with similar patients who did not receive extended-duration LMWH. This effect was not sustained, however, when the groups were compared for VTE diagnosis within 90 days of surgery.

Does Heparin Prophylaxis Reduce the Risk of Venous Thromboembolism in Patients Undergoing Robot-Assisted Prostatectomy?

Venous thromboembolism (VTE) is a major complication of urologic surgery. Data are limited regarding the benefits of heparin prophylaxis for patients undergoing minimally invasive urologic surgery. The American Urological Association recommends sequential compression devices (SCDs) for urologic laparoscopic and robot-assisted procedures but provides no clear recommendations for the use of pharmacologic prophylaxis. We compare the rates of postoperative VTE in two groups of patients undergoing robot-assisted prostatectomy (RP) by two surgeons-one who consistently used heparin with SCDs (group 1) and the other who used SCDs alone (group 2) for prophylaxis. An Institutional Review Board approved, prospectively managed database was analyzed. Group 1 received SCDs just before induction and 5000 units of heparin subcutaneously just after induction. SCDs were continued postoperatively, and heparin was administered twice a day until discharge. VTE rate, patient age, body mass index (BMI), operative time, lymphocele rate, length of stay (LOS), estimated blood loss (EBL), Gleason score, and pathologic stage were compared. Categorical variables were analyzed with the chi square test of proportions and continuous variables with t test using SPSS v 14 software. There were 1486 consecutive patients who underwent RP between August 2007 and December 30, 2011. Of these, 922 patients received heparin/SCDs and 564 received SCDs alone. Age, BMI, EBL, medial LOS, Gleason score, and pathologic stage were the same in the two groups. There was a higher rate of positive nodes in group 2 (1.3% vs 3.5%). There was one lymphocele in each group. Although operative times were longer in group 2 (229 vs 170 min, P<0.001), the incidence of VTE was not statistically different (1.0% vs 0.7%, P=0.78). BMI, operative time, EBL, and the performance of lymph node dissection were not associated with VTE. The risk of VTE in patients undergoing RP is low and not significantly reduced with the administration of prophylactic heparin/SCDs compared with SCDs alone.

Nomograms to predict risk of in-hospital and post-discharge venous thromboembolism after abdominal and thoracic surgery: an American College of Surgeons National Surgical Quality Improvement Program analysis

BackgroundPostoperative venous thromboembolism (VTE) is increasingly viewed as a quality of care metric, although risk-adjusted incident rates of postoperative VTE and VTE after hospital discharge (VTEDC) are not available. We sought to characterize the predictors of VTE and VTEDC to develop nomograms to estimate individual risk of VTE and VTEDC. MethodsUsing the American College of Surgeons National Surgical Quality Improvement Program database, we identified 471,867 patients who underwent inpatient abdominal or thoracic operations between 2005 and 2010. We excluded primary vascular and spine operations. We built logistic regression models using stepwise model selection and constructed nomograms for VTE and VTEDC with statistically significant covariates. ResultsThe overall, unadjusted, 30-d incidence of VTE and VTEDC was 1.5% and 0.5%, respectively. Annual incidence rates remained unchanged over the study period. On multivariate analysis, age, body mass index, presence of preoperative infection, operation for cancer, procedure type (spleen highest), multivisceral resection, and non-bariatric laparoscopic surgery were significant predictors for VTE and VTEDC. Other significant predictors for VTE, but not VTEDC, included a history of chronic obstructive pulmonary disease, disseminated cancer, and emergent operation. We constructed and validated nomograms by bootstrapping. The concordance indices for VTE and VTEDC were 0.77 and 0.67, respectively. ConclusionsSubstantial variation exists in the incidence of VTE and VTEDC, depending on patient and procedural factors. We constructed nomograms to predict individual risk of 30-d VTE and VTEDC. These may allow more targeted quality improvement interventions to reduce VTE and VTEDC in high-risk general and thoracic surgery patients.

Hospital Episode Statistics data analysis of postoperative venous thromboembolus in patients undergoing urological surgery: a review of 126,891 cases

IntroductionCurrent guidelines on venous thromboembolism (VTE) prevention do not reflect the potential varying risk for patients undergoing different urological procedures. Our study aimed to establish the procedure specific rate of postoperative VTE in patients undergoing urological surgery.MethodsHospital Episode Statistics were obtained for all patients undergoing common urological procedures between April 2009 and April 2010. This cohort was followed up to identify all patients reattending with either deep vein thrombosis (DVT) or pulmonary embolism (PE) within 12 months.ResultsA total of 126,891 individuals underwent urological surgery during the study period. This included 89,628 men (70.6%) and 37,236 women (29.3%) with a mean age of 65.2 years. At the 12-month follow-up, 839 patients (0.66%) were readmitted with VTE. Of these, 373 (0.29%) were admitted with DVT and 466 (0.37%) with PE. The procedure-specific rate of VTE varied significantly between 2.86% following cystectomy and 0.23% following urethral dilatation. Procedures performed in the lithotomy position carried a significantly lower risk of VTE than those performed in the supine position (0.60% vs 1.28%, p<0.0001). Furthermore, of all procedures performed in the lithotomy position, those performed on benign conditions carried a significantly lower risk than those performed on malignant disease (0.52% vs 0.79%, p<0.0001).ConclusionsProcedure specific rates of postoperative VTE vary widely among patients undergoing urological procedures. These findings suggest the potential benefit of prolonging the use of thromboprophylaxis in high-risk patients but also exploring the apparent lack of need for routine thromboprophylaxis in patients undergoing low-risk procedures.

Predictors of deep venous thrombosis in patients admitted to rehabilitation clinics after major orthopaedic surgery

Venous thromboembolism (VTE) is a frequent complication of major orthopaedic surgery; prolonged prophylaxis with anticoagulants is standard of care. However, late manifestation of VTE is common and little is known about the predictors of late deep vein thrombosis (DVT) and the distribution of proximal and distal DVT and isolated calf muscle vein thrombosis (MVT). 482 patients admitted to a rehabilitation clinic (RC) after total hip or knee replacement (THR; TKR) or hip fracture surgery (HFS) underwent complete compression ultrasound (CCUS) screening for VTE within 72 hours after admission into RC. Predictors of VTE were evaluated. DVT was prevalent in 74 events (14.7 %), consisting of 13 (2.7 %) proximal DVT, 17 (3.5 %) distal DVT and 41 (8.5 %) MVT, respectively. Multivariate analyses established history of VTE (OR for proximal DVT 7.0; 95 %-CI 1.9 - 25.9; OR for any DVT 3.9; 95 %-CI 1.7 - 8.9), female gender (OR 3.3; 95 %-CI 1.0 - 10.6), coronary artery disease (OR 3.8; 95 %-CI 1.1 - 12.9) and cancer (OR 8.0; 95 %-CI 1.8 - 35.5) as independent VTE predictors for proximal DVT. For MVT, age (OR 2.4; 95 %-CI 1.2 - 5.0) and a history of musculo-skeletal disease (OR 2.6; 95 %-CI 1.1 - 5.8) or autoimmune disease (OR 3.9; 95 %-CI 1.0 - 15.4) were found to be independent predictors. This study confirms well-known predictors of VTE and high rates of postoperative VTE despite optimal thromboprophylaxis. In addition, independent risk factors for proximal DVT and MVT were identified. The data support the concept or continuing thromboprophylaxis during rehabilitation after major orthopaedic surgery because a considerable percentage of patients had asymptomatic DVT at RC on admission. However, significant differences in the individual risk profile and the distribution pattern of DVT and MVT exist, which could be used for a more individualized thromboprophylaxis strategy.

The Incidence of Venous Thromboembolism (VTE) After Hip Arthroscopy (SS-43)

The true incidence of VTE following hip arthroscopy is not known. Salvo et. al. have recently reported a symptomatic DVT rate of 3.7% following these procedures. This number was based on a retrospective study in which only symptomatic patients were tested. However, the clinical signs and symptoms of VTE in post operative patients lack sensitivity and specificity. Thus, it is important to screen all patients to obtain a more accurate incidence of VTE. Understanding the true rate of VTE will allow us to better determine what type of VTE prophylaxis, if any, is needed for these patients. We postulate that prolonged traction on the limb as well as proximity to pelvic vasculature may place patients undergoing hip arthroscopy at increased risk of developing VTE. The purpose of this study is to determine our institution's incidence of venous thromboembolism after hip arthroscopy. This is an IRB approved retrospective study. Over the course of one year (August 2010-August 2011), four surgeons that routinely perform hip arthroscopy began a protocol to screen all patients post-operatively for deep venous thrombosis (DVT) using bilateral venous duplex ultrasound at or about the two-week post-operative time point. Patients did not receive mechanical prophylaxis intra-operatively, and were excluded if they received pharmacologic prophylaxis post-operatively. Patient risk factors for VTE were assessed and recorded. Peri-operative factors, such as weight bearing status after surgery, traction time, and anesthesia type were recorded. We identified 144 patients over the course of this time period that underwent hip arthroscopy. 61% of were women and 39% were male. Five patients were excluded for receiving pharmacologic prophylaxis after the procedure. The average age was 37.7 (SD=12.0). The average BMI was 25.9. The average traction time was 58.9 minutes. Ninety six percent of patients received general anesthesia. Most patients (71%) were partial weight bearing after the procedure. Overall, our incidence of VTE was 1.4 percent (2/139). There were two symptomatic venous thromboembolic events noted; one DVT and one pulmonary embolus. One patient had no risk factors; the other was overweight and routinely took oral contraceptives. Of the entire patient pool, 81 obtained a follow-up ultrasound. There were no cases of asymptomatic VTE. To our knowledge, this is the first study using routine ultrasound to screen patients for post-operative VTE after hip arthroscopy. In patients undergoing hip arthroscopy, the rate of post-operative VTE is low, despite the use of prolonged axial traction and surgical proximity to the pelvic veins. We believe that routine use of pharmacologic prophylaxis is not indicated unless the patient has other risk factors that would place them at a high risk for developing VTE after a routine outpatient surgical procedure.

Symptomatic In-Hospital Deep Vein Thrombosis and Pulmonary Embolism Following Hip and Knee Arthroplasty Among Patients Receiving Recommended Prophylaxis

Symptomatic venous thromboembolism (VTE) after total or partial knee arthroplasty (TPKA) and after total or partial hip arthroplasty (TPHA) are proposed patient safety indicators, but its incidence prior to discharge is not defined. To establish a literature-based estimate of symptomatic VTE event rates prior to hospital discharge in patients undergoing TPHA or TPKA. Search of MEDLINE, EMBASE, and the Cochrane Library (1996 to 2011), supplemented by relevant articles. Reports of incidence of symptomatic postoperative pulmonary embolism or deep vein thrombosis (DVT) before hospital discharge in patients who received VTE prophylaxis with either a low-molecular-weight heparin or a subcutaneous factor Xa inhibitor or oral direct inhibitor of factors Xa or IIa. Meta-analysis of randomized clinical trials and observational studies that reported rates of postoperative symptomatic VTE in patients who received recommended VTE prophylaxis after undergoing TPHA or TPKA. Data were independently extracted by 2 analysts, and pooled incidence rates of VTE, DVT, and pulmonary embolism were estimated using random-effects models. The analysis included 44,844 cases provided by 47 studies. The pooled rates of symptomatic postoperative VTE before hospital discharge were 1.09% (95% CI, 0.85%-1.33%) for patients undergoing TPKA and 0.53% (95% CI, 0.35%-0.70%) for those undergoing TPHA. The pooled rates of symptomatic DVT were 0.63% (95% CI, 0.47%-0.78%) for knee arthroplasty and 0.26% (95% CI, 0.14%-0.37%) for hip arthroplasty. The pooled rates for pulmonary embolism were 0.27% (95% CI, 0.16%-0.38%) for knee arthroplasty and 0.14% (95% CI, 0.07%-0.21%) for hip arthroplasty. There was significant heterogeneity for the pooled incidence rates of symptomatic postoperative VTE in TPKA studies but less heterogeneity for DVT and pulmonary embolism in TPKA studies and for VTE, DVT, and pulmonary embolism in TPHA studies. Using current VTE prophylaxis, approximately 1 in 100 patients undergoing TPKA and approximately 1 in 200 patients undergoing TPHA develops symptomatic VTE prior to hospital discharge.

Systematic review and meta-analysis on the rate of postoperative venous thromboembolism in orthopaedic surgery in Asian patients without thromboprophylaxis

Postoperative venous thromboembolism (VTE) is a common life-threatening complication after surgery. This review analysed the rate and mortality of VTE after orthopaedic surgery in Asia. Inclusion criteria were: prospective study; deep vein thrombosis (DVT) diagnosed by venography or ultrasonography; hip fracture surgery (HFS), total hip arthroplasty (THA) or total knee arthroplasty (TKA); and no thromboprophylaxis. The pooled proportion was back-calculated by Freeman-Tukey variant transformation, using a random-effects model. Twenty-two studies (total population 2454) published from 1979 to 2009 were included. Using venography, the pooled rates of all-site, proximal, distal and isolated distal DVT were 31·7, 8·9, 22·5 and 18·8 per cent respectively. With duplex ultrasonography, the respective rates were 9·4, 5·9, 5·9 and 5·8 per cent. After THA or HFS, using venography, the pooled rates of all-site and proximal DVT were 25·8 and 9·6 per cent; with ultrasonography, the respective rates were 10·8 and 7·2 per cent. In TKA groups, using venography, the pooled rates of all-site and proximal DVT were 42·5 and 8·7 per cent; with ultrasonography, the respective rates were 9·5 and 5·2 per cent. The overall pooled rates of symptomatic DVT and symptomatic pulmonary embolism (PE) were 4·5 and 0·6 per cent. No patient died from PE (pooled rate 0·2 per cent). None of these Asian patients undergoing orthopaedic surgery died from VTE. Pooled rates of proximal and symptomatic DVT were lower than in Western reports.

Preoperative Placement of Inferior Vena Cava Filters and Outcomes After Gastric Bypass Surgery

To assess relationships between inferior vena cava (IVC) filter placement and complications within 30 days of gastric bypass surgery. IVC filters are increasingly being used as prophylaxis against postoperative pulmonary embolism in patients undergoing bariatric surgery, despite a lack of evidence of effectiveness. On the basis of data from a prospective clinical registry involving 20 Michigan hospitals, we identified 6376 patients undergoing gastric bypass surgery between 2006 and 2008. We then assessed relationships between IVC filter placement and complications within 30 days of surgery. We used propensity scores and fixed effects logistic regression to control for potential selection bias. A total of 542 gastric bypass patients (8.5%) underwent preoperative IVC filter placement, most of whom (65%) had no history of venous thromboembolism. The use of IVC filters for gastric bypass patients varied widely across hospitals (range, 0%-34%). IVC filter patients did not have reduced rates of postoperative venous thromboembolism (adjusted odds ratio [OR], = 1.28; 95% confidence interval [CI], 0.51-3.21), serious complications (adjusted OR, = 1.40; 95% CI, 0.91-2.16), or death/permanent disability (adjusted OR, = 2.49; 95% CI, 0.99-6.26). More than half (57%) of the IVC filter patients in the latter group had a fatal pulmonary embolism or complications directly related to the IVC filter itself, including filter migration or thrombosis of the vena cava. In subgroup analyses, we were unable to identify any patient group for whom IVC filters were associated with improved outcomes. Prophylactic IVC filters for gastric bypass surgery do not reduce the risk of pulmonary embolism and may lead to additional complications.

Eradication of hospital-acquired venous thromboembolism

Pulmonary embolism (PE) causes nearly 200,000 deaths annually in the United States alone. The magnitude of the risk for acquiring venous thromboembolism (VTE) in U.S. hospitals is staggering (1). About 8 million Medical Service and 4 million Surgical Service patients are at moderate or high risk for developing VTE each year (2). The surgeon General has declared that PE is the most preventable cause of death within hospitals (3). Thus, a spotlight shines brightly on quality control and quality improvement practices within American hospitals (4) to ensure that maximum effort is exerted to prevent PE and deep venous thrombosis (DVT). A convergence of passionate advocates (5), including health care providers, patients, and governmental authorities, will transform the status quo and enable eradication of hospital-acquired VTE. Catalysts for VTE eradication are listed in Table 1. Failure to prevent in-hospital PE and DVT will no longer be tolerated. For example, Medicare and Medicaid will have stopped reimbursing hospitals for incremental care needed to treat postoperative total hip or knee replacement patients who develop VTE (6). Whether this new policy is wise or equitable is debatable (7), but its influence in augmenting VTE prophylaxis and in decreasing the rate of postoperative VTE is undeniable. We have entered a new era that focuses on venous disease. This contemporary heightened awareness to VTE prevention constitutes a remarkable achievement. Only a decade ago, VTE was an orphan disease which received only a modicum of attention from major cardiology, pulmonary, and haematology specialty societies. Major organisations representing these specialties were concerned about VTE but did not embrace the field as a top priority. Transformative champions who had argued in favour of paying more attention to preventing venous thrombosis had to compete with more forceful voices that favoured emphasis on more traditional core subject matter for each organisation. Examples are acute coronary syndrome for cardiologists, asthma/chronic lung disease for pulmonologists, and leukaemia/lymphoma for haematologists. Venous disease education tended to be handled as an “afterthought.” Discussion of VTE’s wide scope and potential for harm did not capture the imagination of professionals or the public. Apathy was a common response when the subject of VTE was raised. There was no unifying push toward universal protection of hospitalised patients against DVT and PE.

Venous thromboembolism and mortality after hip fracture surgery: the ESCORTE study1,2

Recent changes in the management of hip fracture surgery patients may have modified the epidemiology of postoperative complications. We performed an observational study of a cohort of patients undergoing hip fracture surgery to update the epidemiological data on this population. The primary study outcome was the incidence of confirmed symptomatic venous thromboembolism (VTE) [defined as deep vein thrombosis, pulmonary embolism (PE), or both] at 3 months. Overall mortality at 1, 3 and 6 months was also evaluated. Consecutive patients aged at least 18 years hospitalized in French public or private hospitals (531 centers) undergoing hip fracture surgery were recruited prospectively during 2 months in 2002 and a follow-up at 6 months. Predictive factors for VTE at 3 months and for death at 6 months were also analyzed. Data from 6860 (97.3%) of the 7019 recruited patients were included in the analysis. The median age was 82 years. Low molecular weight heparins were administered perioperatively in 97.6% of patients; 69.5% received this treatment for at least 4 weeks. The actuarial rate of confirmed symptomatic VTE at 3 months was 1.34% (85 events, 95% CI: 1.04-1.64). There were 16 PEs (actuarial rate: 0.25%), three of which were fatal. Overall, 1006 (14.7%) patients were dead at 6 months. Cardiovascular disease was the most frequent cause of death (270 patients; 26.8%). The current rate of postoperative VTE is low, but overall mortality remains high. Indeed, hip fracture patients belong to a vulnerable group of old people with comorbid diseases and a high risk of postoperative morbidity and mortality. An interdisciplinary approach could be the challenge to improve short and long-term outcome.

Can We Do Better? Identifying Orthopedic Surgery Patients at High Risk for Venous Thromboembolism Despite Thromboprophylaxis.

BackgroundRoutine administration of thromboprophylaxis is the standard of care for patients undergoing major orthopedic surgery due to the very high rate of postoperative venous thromboembolism (VTE). However, because prophylaxis is not 100% effective, a significant proportion of patients who receive thromboprophylaxis develop post-operative VTE (“breakthrough VTE”). Clinical and surgical characteristics that are associated with the development of VTE in orthopedic surgery patients who receive standard thromboprophylaxis have not been well characterized.ObjectivesTo evaluate the incidence of and risk factors for breakthrough VTE in patients who underwent major orthopedic surgery at a tertiary care hospital in Montreal, Canada.MethodsCharts from consecutive patients who underwent total hip arthroplasty (THA), total knee arthroplasty (TKA) or hip fracture surgery (HFS) (hip pinning or hemiarthroplasty) from August 1, 1999 to April 30, 2000 were abstracted using standardized case report forms. Data were collected on patient characteristics (including VTE risk factors and postoperative complications), surgical characteristics (including type of surgery, operative factors, type of anesthetic) and thromboprophylaxis regimen. The results of any tests performed for clinically suspected VTE were documented, and associations between potential risk factors and objectively confirmed VTE were examined.ResultsOver the 9 month study period, 310 patients underwent major orthopedic surgery (34% THA, 30% TKA, and 36% HFS) and received standard thromboprophylaxis with either dalteparin or enoxaparin (mean duration of prophylaxis: 7 days). Of 83 suspected VTE, 44 (7 proximal DVTs and 37 distal DVTs; 14% of study population; median onset 6 days post-op) were confirmed with objective testing (compression ultrasonography). Multivariate analyses showed that knee surgery (odds ratio [OR] 4.8, 95% confidence interval 2.3, 10.1) and type of low molecular weight heparin (enoxaparin: protective) (OR 0.39, 95% confidence interval 0.20, 0.80) independently predicted VTE. Patient characteristics such as previous VTE, malignancy, hormonal therapy or varicose veins were not associated with VTE.Conclusion Despite receiving standard thromboprophylaxis, 14% of patients undergoing major orthopedic surgery developed symptomatic breakthrough VTE. Factors that independently predicted VTE in our population were TKR surgery and type of low molecular weight heparin. Our results suggest that TKR patients may warrant more aggressive post-operative physiotherapy and ambulation and adjunctive prophylactic measures such as pneumatic compression. In addition, due to the heterogeneity of different low molecular weight heparin compounds, direct comparison of the effectiveness of enoxaparin with dalteparin for orthopedic prophylaxis in prospective, randomized trials seems warranted.

New therapeutic options in deep vein thrombosis prophylaxis

Joint replacement surgery is complicated by a high rate of postoperative venous thromboembolism (VTE). Current thromboprophylactic approaches reduce the rate of VTE, but the incidence remains as high as 20% to 50%. Recombinant hirudins, such as desirudin and lepirudin, function by directly inhibiting thrombin, and are a new development in antithrombotic therapy. In two multicenter studies, desirudin was found to be superior to unfractionated heparin (UFH) in the prevention of deep vein thrombosis (DVT) after total hip alloplasty. A further trial of more than 2,000 patients undergoing elective hip replacement compared the thromboprophylactic efficacy of desirudin versus the low-molecular-weight heparin (LMWH) enoxaparin. Desirudin was more effective than LMWH in providing effective prophylaxis, and maintained superiority in patients with additional risk. Desirudin was shown to be equally safe and did not require laboratory monitoring. Desirudin (15 mg twice daily) is an efficient therapy for DVT prevention in hip alloplasty patients at additional risk.