Prophylaxis of Venous Thromboembolism Using Two Different Doses of Low-Molecular-Weight Heparin (Nadroparin) in Bariatric Surgery: A Prospective Randomized Trial

Background: Obese patients undergoing bariatric surgery are at a high risk of developing fatal pulmonary embolism or post-thrombotic syndrome.The prophylactic use of low molecular weight heparins (LMWHs) is correlated with a significant reduction in post-operative venous thrombosis in patients undergoing orthopedic or general surgery. In morbidity obese patients, the limited number of comparative trials are too sparse to allow a consensus on the effective dose and dosing schedule. Methods: In a prospective study to evaluate the effect of two doses of nadroparin as prophylaxis for venous thromboembolism following bariatric surgery, 60 consecutive patients undergoing Rouxen-Y gastric bypass were randomized to receive either 0.6 ml (5700 IU) or 1.0 ml (9500 IU) of nadroparin started pre-operatively and then given once daily post-operatively until discharge. Results: No statistically significant differences between the two groups were detected in any of the measured coagulation parameters either preoperatively or at days 1, 3 and 5 postoperatively.No thrombotic events were observed pre- or post- operatively, and no patient developed meta-thrombotic syndrome at the 3 and 6 months follow-up. No bleeding events occurred in the patients given the lower dose compared with two major hemorrhages in those given the higher dose. Conclusion: Our results indicate that 0.6 ml (5700 IU) of nadroparin once daily is safe and well-tolerated, and it is as effective in prophylaxis of venous thromboembolism as the higher dose of 1 ml (9500 IU), in such high risk patients.     

Heparin-induced thrombocytopenia after elective hip joint replacement with postoperative prevention of thromboembolism with low-molecular-weight heparin

BACKGROUND: Heparin-induced thrombocytopenia (HIT) is a severe side effect of the prophylaxis of venous thromboembolism with unfractionated heparin. The aim of the present study is to gain more information on the incidence of HIT during prophylaxis of venous thromboembolism with low-molecular-weight heparin in elective hip surgery. METHODS: 586 consecutive patients were included into the prospective study, who were admitted to hospital for elective hip replacement. The incidence of thrombocytopenia, clinically manifest venous thromboembolism and of the heparin-induced IgG antibodies were analysed during prophylaxis with low molecular-weight heparin. Patients received once daily subcutaneously low molecular-weight heparin for a mean of 28 days postoperatively. Platelet counts and clinical examinations for the presence of venous thromboembolism were done at days 0, 2, 7 (+/- 1) and 12 (+/- 2). Heparin-induced IgG antibodies were determined before and after a 12 (+/- 2) days prophylaxis with low molecular-weight heparin in 265 of 586 patients randomly. Patients were reexamined for thromboembolic complications after 3 and 6 months. The clinical suspicion of thromboembolic complication was documented objectively. RESULTS: None of the patients developed a decrease of platelets of < 50% of the initial value. Ten of 265 patients had elevated IgG antibodies against heparin/platelet factor 4 before prophylaxis (3.8%). After the 12 (+/- 2) days prophylaxis 13 of 265 patients had elevated IgG antibodies (4.9%). C14 serotonin assay was positive in 0 of 10 patients before treatment and in 3 of 19 patients at day 12 (+/- 2). Ten patients developed venous thromboembolism postoperatively (8 x deep venous thrombosis, 2 x pulmonary embolism, no fatal embolism). Only 1/19 patients with elevated antiheparin IgG titres developed venous thromboembolism. The C14 serotonin assay was negative in this patient. Two patients died in the postoperative phase due to underlying cardiovascular diseases. CONCLUSIONS: In patients with elective hip replacement prophylaxis of venous thromboembolism with low molecular-weight heparin was associated with a very low incidence of HIT, and hence screening for HIT antibodies is not required.     

Enoxaparin for Thromboprophylaxis in Morbidly Obese Patients Undergoing Bariatric Surgery: Findings of the Prophylaxis Against VTE Outcomes in Bariatric Surgery Patients Receiving Enoxaparin (PROBE) Study

Background: Obese patients undergoing bariatric surgery are at significant risk for venous thromboembolism (VTE). We performed a multicenter, retrospective survey to evaluate the safety and efficacy of enoxaparin for thromboprophylaxis in patients with morbid obesity undergoing primary bariatric surgery. Methods: From January to December 2002, 668 patients who underwent primary bariatric surgery at 5 centers were analyzed retrospectively. Baseline patient demographics, objectively diagnosed cases of VTE, and bleeding events were recorded. Patients received enoxaparin preoperatively (30 mg) or postoperatively (40 mg) every 12 or 24 hours or upon discharge (30 mg every 24 hours for 10 days). Results: Overall, there were 6 (0.9%) pulmonary embolisms (PE) and 1 (0.1%) occurrence of deep vein thrombosis (DVT); all but 1 occurred after the cessation of thromboprophylaxis. The highest incidence of VTE was at Center B, which did not administer perioperative thromboprophylaxis (1 DVT and 2 PEs). There were 6 (0.9%) severe bleeding complications: 3 at center D and 3 at center E. In Center B, 2 deaths were recorded (0.3%): 1 due to sepsis and 1 due to bleeding, with both occurring after thromboprophylaxis was discontinued. Conclusion: The administration of enoxaparin, in various dosing regimens, is safe for thromboprophylaxis in morbidly obese patients undergoing bariatric surgery. Fewer events occurred with perioperative prophylaxis initiated in the hospital. Because all thromboembolic events occurred after the cessation of thromboprophylaxis, extended thromboprophylaxis may be of value.     

Efficacy of a postoperative regimen of enoxaparin in deep vein thrombosis prophylaxis.

Venous thromboembolism is a common complication in patients undergoing elective hip replacement, in whom the incidence of calf vein thrombosis is 40% to 60%; proximal vein thrombosis, 20%; and fatal pulmonary embolism, 1% to 2% when prophylaxis is not used. A double-blind, randomized trial comparing low-molecular-weight heparin (enoxaparin) with placebo for the prevention of venous thrombosis in patients undergoing elective hip surgery was carried out. Prophylactic treatment with a fixed dose was begun postoperatively and continued for 14 days. Fifty patients in each treatment group underwent surveillance with 125I-fibrinogen leg scanning and impedance plethysmography. In the first 24 patients, venography was performed only if their surveillance test was positive. Venography was requested in the remaining 76 patients even if the screening tests were negative; in this latter group, venous thrombosis occurred in 4 patients (10.8%) given enoxaparin and 20 patients (51.3%) given placebo (p = 0.0002). The corresponding rates for proximal vein thrombosis were 5.4% and 23.1%, respectively (p = 0.029). In the entire group of 100 patients, venous thrombosis occurred in 12% of those given enoxaparin and 42% of those given placebo (p = 0.0007). The corresponding rates for proximal vein thrombi were 4% and 20%, respectively (p = 0.014). The observed hemorrhagic rate was 5% in each treatment group. The results of this study show that prophylaxis with fixed-dose enoxaparin is effective and safe for patients undergoing elective hip replacement.     

What is the optimum strategy for thromboembolic prophylaxis following extrapleural pneumonectomy in patients with malignant pleural mesothelioma?

Malignant pleural mesothelioma (MPM) increases the risk of venous thromboembolic (VTE) events. This risk is higher following extrapleural pneumonectomy (EPP) as part of trimodality therapy, where VTE can be catastrophic. In our series, the impact of warfarin in preventing a pulmonary embolus (PE) after neoadjuvant chemotherapy and EPP for MPM was analysed. A retrospective analysis of 21 consecutive patients undergoing EPP for MPM was conducted. The first 10 patients (Group A) had VTE prophylaxis by subcutaneous enoxaparin and compression stockings commenced a day prior to surgery, intraoperative pneumatic calf compression and early post-operative mobilization. Enoxaparin was continued for 30 days postoperatively. The following 11 patients (Group B) had the same VTE prophylaxis, together with warfarin, started prior to hospital discharge and continued for 6 months postoperatively. All patients had a computed tomography pulmonary angiogram within 8 weeks after surgery and a full examination at 1, 3, 6 and 12 months. Both groups were comparable for characteristics. Three patients in Group A suffered a PE at 4, 6 and 16 weeks postoperatively. One PE was fatal. No patient in Group B suffered VTE (P = 0.05, χ(2) test) or haemorrhagic complications. Warfarin anticoagulation following EPP is feasible and safe, and is associated with a significant reduction in VTE complications.     

Subcutaneous heparin versus low-molecular-weight heparin as thromboprophylaxis in patients undergoing colorectal surgery: results of the canadian colorectal DVT prophylaxis trial: a randomized, double-blind trial

OBJECTIVE: To compare the effectiveness and safety of low-dose unfractionated heparin and a low-molecular-weight heparin as prophylaxis against venous thromboembolism after colorectal surgery. METHODS: In a multicenter, double-blind trial, patients undergoing resection of part or all of the colon or rectum were randomized to receive, by subcutaneous injection, either calcium heparin 5,000 units every 8 hours or enoxaparin 40 mg once daily (plus two additional saline injections). Deep vein thrombosis was assessed by routine bilateral contrast venography performed between postoperative day 5 and 9, or earlier if clinically suspected. RESULTS: Nine hundred thirty-six randomized patients completed the protocol and had an adequate outcome assessment. The venous thromboembolism rates were the same in both groups. There were no deaths from pulmonary embolism or bleeding complications. Although the proportion of all bleeding events in the enoxaparin group was significantly greater than in the low-dose heparin group, the rates of major bleeding and reoperation for bleeding were not significantly different. CONCLUSIONS: Both heparin 5,000 units subcutaneously every 8 hours and enoxaparin 40 mg subcutaneously once daily provide highly effective and safe prophylaxis for patients undergoing colorectal surgery. However, given the current differences in cost, prophylaxis with low-dose heparin remains the preferred method at present.     

Enoxaparin thromboprophylaxis in gastric bypass patients: extended duration,dose stratification,and antifactor Xa activity

BackgroundMorbidly obese patients undergoing gastric bypass surgery are at risk for postoperative venous thromboembolism. Evidence-based recommendations regarding the dosing and duration of thromboprophylaxis are lacking for morbidly obese surgical patients. The aims of this study were to evaluate the safety and efficacy of an extended duration, body mass index (BMI)–stratified enoxaparin thromboprophylaxis regimen in patients undergoing Roux-en-Y gastric bypass and to determine the resultant antifactor Xa (AFXa) activity in morbidly obese surgical patients.MethodsIn this prospective open trial, 223 patients (75% female, mean BMI 50.4 kg/m²) undergoing Roux-en-Y gastric bypass were assigned to receive enoxaparin 40 mg (BMI ≤50 kg/m², n = 124) or 60 mg (BMI >50 kg/m², n = 99) every 12 hours during hospitalization and once daily for 10 days after discharge. The AFXa levels were monitored serially, and dose adjustments were made for results outside the target prophylactic range (.2–.4 IU/mL ± 10%) after the third dose. The safety and efficacy outcomes were major bleeding and venous thromboembolism.ResultsRoux-en-Y gastric bypass was performed laparoscopically in 208 subjects (93%). The duration of surgery averaged 99.5 ± 31 minutes, and the median length of hospitalization was 3 days. Target prophylactic AFXa concentration was achieved by 74% of patients after the third enoxaparin dose; none reached the full anticoagulation concentration. One patient developed nonfatal venous thromboembolism (.45%). Four patients required transfusion (1.79%). Bleeding was not associated with a high AFXa concentration.ConclusionThis BMI-stratified, extended enoxaparin dosing regimen provided well-tolerated, effective prophylaxis against venous thromboembolism in patients undergoing gastric bypass surgery.     

Is bariatric surgery safe in patients who refuse blood transfusion?

BackgroundA small, but significant, number of patients undergoing bariatric surgery refuse blood transfusion for religious or other personal reasons. Jehovah's Witnesses number more than 1 million members in the United States alone. The reported rates of hemorrhage vary from .5% to 4% after bariatric surgery, with transfusion required in one half of these cases. Pharmacologic prophylaxis against venous thromboembolism could further increase the perioperative bleeding risk. Our objective was to report the perioperative outcomes of bariatric surgery who refuse blood transfusion at a bariatric center of excellence, private practice in the United States.MethodsA retrospective review of all patients who refused blood transfusion when undergoing bariatric surgery during a 10-year period was conducted. Patients were identified from a prospectively maintained database by the bloodless surgery program at Legacy Good Samaritan Hospital. Data were collected on demographics, co-morbidities, laboratory values, medication use, blood loss, and 30-day complications.ResultsThirty-five bloodless surgery patients underwent bariatric surgery from 2000 to 2009. Of these 35 patients, 21 underwent laparoscopic adjustable gastric banding and 14 Roux-en-Y gastric bypass. Before 2006, only pneumatic compression devices were applied for venous thromboembolism prophylaxis (n = 6). Subsequently, combination venous thromboembolism prophylaxis was performed with fondaparinux sodium 2.5 mg for RYGB or enoxaparin 40 mg for LAGB (n = 29). One RYGB patient developed postoperative hemorrhage requiring reoperation. No venous thromboembolisms or deaths occurred.ConclusionBariatric surgery can be performed in patients who refuse blood transfusion with acceptable postoperative morbidity. Larger studies are necessary to confirm the safety of this approach and to examine the effect of pharmacologic thromboprophylaxis in this patient group.     

Prolonged enoxaparin therapy to prevent venous thromboembolism after primary hip or knee replacement. Enoxaparin Clinical Trial Group

BACKGROUND: Patients undergoing hip or knee joint replacement are at risk for venous thromboembolic complications for up to twelve weeks postoperatively. We evaluated the efficacy and safety of a prolonged post-hospital regimen of enoxaparin, a low-molecular-weight heparin, in this patient population. METHODS: Following elective total hip or knee replacement, 968 patients received subcutaneous enoxaparin (30 mg twice daily) for seven to ten days, and 873 were then randomized to receive three weeks of double-blind outpatient treatment with either enoxaparin (40 mg once daily) or a placebo. The primary efficacy end point was the prevalence of objectively confirmed venous thromboembolism or symptomatic pulmonary embolism during the double-blind phase of treatment. RESULTS: Of the 873 randomized patients, 435 underwent elective total hip replacement and 438 underwent elective total knee replacement. Enoxaparin was superior to the placebo in reducing the prevalence of venous thromboembolism in patients treated with hip replacement: 8.0% (eighteen) of the 224 patients treated with enoxaparin had venous thromboembolism compared with 23.2% (forty-nine) of the 211 patients treated with the placebo (p < 0.001; odds ratio, 3.62; 95% confidence interval, 2.00 to 6.55; relative risk reduction, 65.5%). Enoxaparin had no significant benefit in the patients treated with knee replacement: thirty-eight (17.5%) of the 217 patients treated with enoxaparin had venous thromboembolism compared with forty-six (20.8%) of the 221 patients treated with the placebo (p = 0.380; odds ratio, 1.24; 95% confidence interval, 0.76 to 2.02; relative risk reduction, 15.9%). Symptomatic pulmonary embolism developed in three patients, one with a hip replacement and two with a knee replacement; all had received the placebo. There was no significant difference in the prevalence of hemorrhagic episodes or other types of toxicity between the enoxaparin and placebo-treated groups. CONCLUSIONS: Prolonging enoxaparin thromboprophylaxis following hip replacement for a total of four weeks provided therapeutic benefit, by reducing the prevalence of venous thromboembolism, without compromising safety. A similar benefit was not observed in patients treated with knee replacement.     

Randomized,pilot study of intermittent pneumatic compression devices plus dalteparin versus intermittent pneumatic compression devices plus heparin for prevention of venous thromboembolism in patients undergoing craniotomy

BACKGROUND: Unfractionated heparin and the low molecular weight heparin, dalteparin, are used for prophylaxis against venous thromboembolism in patients undergoing craniotomy. These drugs were compared in a randomized, prospective pilot study comparing intermittent pneumatic compression devices plus dalteparin to intermittent pneumatic compression devices plus heparin. METHODS: One hundred patients undergoing craniotomy were randomly allocated to receive perioperative prophylaxis with subcutaneous (SC heparin, 5000 units every 12 hours, or dalteparin, 2,500 units once a day, begun at induction of anesthesia and continued for 7 days or until the patient was ambulating. Entry criteria were age over 18 years, no deep vein thrombosis (DVT) preoperatively as judged by lower limb duplex ultrasound and no clinical evidence of pulmonary embolism preoperatively. Patients with hypersensitivity to heparin, penetrating head injury or who refused informed consent were excluded. Patients underwent a duplex study 1 week after surgery and 1 month clinical follow-up. All patients were treated with lower limb intermittent pneumatic compression devices. RESULTS: There were no differences between groups in age, gender, and risk factors for venous thromboembolism. There were no differences between groups in intraoperative blood loss, transfusion requirements or postoperative platelet counts. Two patients receiving dalteparin developed DVT (one symptomatic and one asymptomatic). No patient treated with heparin developed DVT and no patient in either group developed pulmonary embolism. There were two hemorrhages that did not require repeat craniotomy in patients receiving dalteparin and one that did require surgical evacuation in a patient treated with heparin. Drug was stopped in two patients treated with dalteparin because of thrombocytopenia. None of these differences were statistically significant. CONCLUSION: There was no significant difference in postoperative hemorrhage, venous thromboembolism or thrombocytopenia between heparin and dalteparin. The results suggest that, given the small sample size of this trial, both drugs appear to be safe and the incidence of venous thromboembolism by postoperative screening duplex ultrasound appears to be low when these agents are used in combination with intermittent pneumatic compression devices.     

Prophylaxis of thromboembolism in general surgery: problems and perspectives

In 52169 patients, suffering surgical diseases of abdominal cavity and operated in the clinic along 17 years, the prophylactic measures for venous thrombosis and pulmonary thromboembolism were analyzed. Pulmonary thromboembolism have had occurred postoperatively in 0.3% of patients and venous thrombosis--in 7/5%. Specific prophylaxis was done in 54.7%. In 1990-2006 yrs the occurrence rate of pulmonary thromboembolism reduced among other lethality causes from 12.2 to 5.7%. The main problem issues concerning the venous thrombosis and pulmonary thromboembolism prophylaxis in general surgery are enlightened, the perspectives of their solving are determined.     

Thromboembolism Following Foot and Ankle Surgery: A Case Series and Literature Review

Venous thromboembolism following major orthopedic procedures of the hip and knee is well documented and patients are therefore routinely prophylaxed following these proximal lower extremity procedures. In contrast, foot and ankle surgery is considered by most health care professionals to be a low-risk procedure for the development of venous thromboembolism. As a result, pharmacologic deep venous thrombosis prophylaxis is rarely administered. This postoperative practice is supported by the literature regarding deep venous thrombosis following foot and ankle surgery. In this article, we review the risk factors and explore the occurrence of thromboembolism after foot and ankle surgery in the literature. We also present our retrospective study of patients who developed venous thromboembolism after forefoot, midfoot, hindfoot, and ankle procedures. Over the course of 1.5 years, 4 of a consecutive series of 1000 patients (0.4%) developed a deep venous thrombolism and 3 of 1000 (0.3%) developed nonfatal pulmonary emboli. In our series, each of our patients who developed venous thromboembolism had at least 2 identifiable risk factors. The incidence of venous thromboembolism following foot and ankle surgery is rare (less than 1%), and the need for routine propylaxis postoperatively is not supported by any high level of evidence studies. LEVEL OF CLINICAL EVIDENCE: 4.     

Prospective evaluation of the safety of enoxaparin prophylaxis for venous thromboembolism in patients with intracranial hemorrhagic injuries

BACKGROUND: Patients with traumatic intracranial hemorrhagic injuries (IHIs) are at high risk for venous thromboembolism (VTE). The safety of early anticoagulation for IHI has not been established. HYPOTHESIS: Enoxaparin can be safely administered to most patients with IHI for VTE prophylaxis. SETTING: Level I trauma center. DESIGN: Prospective, single-cohort, observational study. PATIENTS AND METHODS: One hundred fifty (85%) of 177 patients with blunt IHI received enoxaparin beginning approximately 24 hours after hospital admission until discharge. Brain computed tomographic (CT) scans were performed at admission, 24 hours after admission, and at variable intervals thereafter based on clinical course. Patients were excluded for coagulopathy, heparin allergy, expected brain death or discharge within 48 hours, and age younger than 14 years. Complications of enoxaparin prophylaxis were defined as Marshall CT grade progression of IHI, expansion of an existing IHI, or development of a new hemorrhagic lesion on follow-up CT after beginning enoxaparin use. RESULTS: Thirty-four patients (23%) had CT progression of IHI. Twenty-eight CT scans (19%) worsened before enoxaparin therapy and 6 (4%) worsened after beginning enoxaparin use. No differences between operative patient (2/24, 8%) and nonoperative patient (4/126, 3%) complications were identified (P =.23). Study group mortality was 7% (10/150). All 6 patients who developed progression of IHI after initiation of enoxaparin therapy survived hospitalization. A deep vein thrombosis was identified in 2 (2%) of 106 patients. CONCLUSION: Enoxaparin can be safely used for VTE prophylaxis in trauma patients with IHI when started 24 hours after hospital admission or after craniotomy.     

A meta-analysis of fondaparinux versus enoxaparin in the prevention of venous thromboembolism after major orthopaedic surgery

A worldwide phase III program, consisting of four randomized, double-blind trials in patients undergoing surgery for hip fracture, in elective hip replacement surgery patients and in elective major knee surgery patients, was conducted to compare the benefit-to-risk ratio of a subcutaneous 2.5-mg once-daily regimen of fondaparinux, a synthetic selective factor Xa inhibitor, starting postoperatively with enoxaparin in preventing venous thromboembolism. The overall incidence of venous thromboembolism up to day 11 was reduced from 13.7% in the enoxaparin group to 6.8% in the fondaparinux group with a common odds reduction of 55.2% in favor of fondaparinux (95% confidence interval: 45.8-63.1%, p = 10(-17)). This superior efficacy of fondaparinux was also demonstrated for proximal deep vein thrombosis with a reduction of 57.4%. The overall incidence of clinically relevant bleeding was low and did not differ between the two groups. The benefit of fondaparinux was consistent across all types of surgery and all subgroups.     

Is routine chemical thromboprophylaxis after total hip replacement really necessary in a Japanese population?

Prophylaxis against venous thromboembolism after elective total hip replacement is routinely recommended. Our preference has been to use mechanical prophylaxis without anticoagulant drugs. A randomised controlled trial was performed to evaluate whether the incidence of post-operative venous thromboembolism was reduced by using pharmacological anticoagulation with either fondaparinux or enoxaparin in addition to our prophylactic mechanical regimen. A total of 255 Japanese patients who underwent primary unilateral cementless total hip replacement were randomly assigned to one of three postoperative regimens, namely injection of placebo (saline), fondaparinux or enoxaparin. There were 85 patients in each group. All also received the same mechanical prophylaxis during and after the operation, regardless of their assigned group. The primary measurement of efficacy was the presence of a venous thromboembolic event by day 11, defined as deep-vein thrombosis detected by ultrasonography, documented symptomatic deep-vein thrombosis or documented symptomatic pulmonary embolism. The duration of follow-up was 12 weeks. The rate of venous thromboembolism was 7.2% with the placebo, 7.1% with fondaparinux and 6.0% with enoxaparin (p = 0.95 for the comparison of all three groups). Our study confirmed the effectiveness and safety of mechanical thromboprophylaxis without the use of anticoagulant drugs after total hip replacement in Japanese patients.     

Clinical efficacy of risk-stratified prophylaxis with low-dose aspirin for the management of symptomatic venous thromboembolism after total hip arthroplasty

BackgroundPulmonary thromboembolism (PTE) and deep vein thrombosis (DVT) are serious complications after total hip arthroplasty (THA). Aspirin has been considered a safe and cost-effective prophylaxis for venous thromboembolism (VTE), and there have been some reports about the incidence of PTE (0%–0.57%) and DVT (0.1%–0.35%) with low-dose aspirin for prophylaxis after THA. The aim of this study was to investigate the incidence of postoperative symptomatic VTE in our hospital and to evaluate the clinical efficacy of our prophylactic regimen.Patient and methodsWe retrospectively reviewed the medical records of consecutive patients who underwent THA in our hospital between 2011 and 2016. A total of 3295 hips (male: 337 patients, 365 hips; female: 2527 patients, 2930 hips) were enrolled in this study. Patients were divided into low-risk and high-risk groups. Low-risk patients were administered aspirin (100 mg/day) for 28 days postoperatively. High-risk patients, such as those diagnosed with obesity and/or with a history of VTE, received anticoagulants (enoxaparin or edoxaban) for 5 days postoperatively, followed by a dose of aspirin for 28 days. Based on our criteria, 218 of 3295 hips were considered high risk.ResultsNo VTE-related mortality was observed. One patient developed symptomatic PTE, and one patient developed symptomatic DVT. Both were successfully treated. Postoperative fatal bleeding or bleeding from any organ such as gastrointestinal and cerebral hemorrhage were not observed. A low incidence (0.03%) was observed for symptomatic DVT and PTE.ConclusionsThis study demonstrated that the hospital's risk-stratified protocol using low-dose aspirin or anticoagulants was clinically effective in preventing symptomatic VTE. These results were considerably better than those reported from Western countries. However, all patients in this study were the Japanese. It was unclear whether similar results were given to non-Japanese patients. Therefore, this protocol needs severe carefulness to be applied to non-Japanese populations.     

Primary prophylaxis of venous thromboembolism in surgical patients

Venous thromboembolism is a major risk for surgical patients during the perioperative period. Prevention of perioperative venous thromboembolism remains a critical component of surgical patient care. The risk for venous thromboembolism in surgical patients can be stratified by their risk factors and by the type of operation. Pharmacological prophylaxis for venous thromboembolism includes unfractionated heparin, low-molecular weight heparin, fondaparinux, warfarin, antiplatelet therapy, and direct thrombin inhibitors. Mechanical devices such as graduated compression stockings, intermittent pneumatic compressions, and venous foot pumps are also effective modalities for venous thromboembolism prophylaxis. The optimal preventive measure of venous thromboembolism should be based on the degree of risk for venous thromboembolism with the intensity of prophylaxis while balancing potential treatment benefits and risks in each individual patient. The epidemiology of venous thromboembolism, the methods for achieving venous thromboembolism prophylaxis, and the approach to institute venous thromboembolism prophylaxis in surgical patients undergoing various operative interventions are reviewed in this article.     

Perioperative thromboprophylaxis in children: development of a guideline for management

Background:  Venous thromboembolic (VTE) events can occur in children at the time of surgery where a patient has associated prothrombotic risk factors. There is currently little advice available to anesthetists on how to assess the risks and provide prophylaxis.
Aim/Objective:  To increase awareness of thrombosis in the perioperative pediatric patient, and to give some guidance when considering prophylaxis in this group.
Method/Results:  A guideline outlining risk factors for venous thromboembolism in patients presenting for surgery was written as a flowchart. Recommendations for low risk patients was early mobilization and good hydration; for moderate risk patients having major general surgery to include physical prophylaxis where size permits, i.e. elastic stockings and compression devices; for high-risk patients undergoing major orthopaedic or general surgery to also receive prophylactic low molecular weight heparin enoxaparin 0.5 mg·kg⁻¹ b.d.
Conclusion:  Children with multiple risk factors for VTE should be considered for prophylactic measures when presenting for prolonged major surgery.     

Venous thromboembolism prevention in surgery and obstetrics: clinical practice guidelines

BACKGROUND AND OBJECTIVE: To produce up-to-date clinical practice guidelines on the prevention of venous thromboembolism in surgery and obstetrics. METHODS: A Steering Committee defined the scope of the topic, the questions to be answered, and the assessment criteria. Eight multidisciplinary working groups (total of 70 experts) performed a critical appraisal of the literature in the following disciplines: pharmacology of antithrombotic agents, orthopaedics; general surgery (gastrointestinal (GI) and varicose vein surgery); urology; gynaecology and obstetrics; thoracic, cardiac and vascular surgery; surgery of the head, neck and spine; and surgery of burns patients. The resultant reports and guidelines were submitted for comment and completion of the Appraisal of Guidelines Research & Evaluation questionnaire to a total of 150 peer reviewers, before producing definite guidelines. RESULTS: The report answers the following questions for each type of surgery: (i) What is the venous thromboembolism incidence according to clinical and/or paraclinical criteria in the absence of prophylaxis? (with stratification of venous thromboembolism risk into low, moderate and high categories); (ii) What is the efficacy and safety of the prophylactic measures used? (iii) When should prophylaxis be introduced and how long should it last? (iv) Does ambulatory surgery affect efficacy and safety of prophylaxis? CONCLUSIONS: Apart from answering the above questions, the guidelines provide a summary table for each discipline. This table stratifies types of surgery into the three risk categories, specifies the recommended prophylaxis for venous thromboembolism (pharmacological and/or mechanical) and grades each recommendation. In addition, whenever appropriate, the recommended prophylaxis is adjusted to low- and high-risk patients.     

Prevention of venous thromboembolic disease following primary total knee arthroplasty. A randomized, multicenter, open-label, parallel-group comparison of enoxaparin and warfarin

BACKGROUND: Patients treated with total knee arthroplasty are at high risk for the development of venous thromboembolism postoperatively. This study compared the efficacy and safety of two common thromboprophylactic agents, enoxaparin (a low-molecular-weight heparin) and warfarin. METHODS: Three hundred and forty-nine patients were included in a prospective, randomized, multicenter, open-label, parallel-group clinical trial. Treatment with enoxaparin (30 mg, administered subcutaneously twice daily) or warfarin (adjusted to an international normalized ratio of 2 to 3) was initiated during the immediate postoperative period, within eight hours after the surgery, and was continued for four to fourteen days. Venous thromboembolism was defined as deep-vein thrombosis documented by contrast venography, symptomatic deep-vein thrombosis documented by lower-extremity ultrasonography, or symptomatic pulmonary embolism confirmed by a positive lung scan or pulmonary angiography. RESULTS: In the all-treated-patients group, eighty (45%) of the 176 warfarin-treated patients had venous thromboembolism: fifty-nine (34%) had distal deep-vein thrombosis; twenty (11%), proximal deep-vein thrombosis; and one (0.6%), pulmonary embolism. Venous thromboembolism developed in significantly fewer (p = 0.0001) enoxaparin-treated patients (forty-four of 173; 25%): forty-one (24%) had distal deep-vein thrombosis, three (2%) had proximal deep-vein thrombosis, and none had pulmonary embolism. The enoxaparin-treated patients also had a significantly lower prevalence of proximal deep-vein thrombosis (p = 0.002). The estimated odds for the development of venous thromboembolism were 2.52 times greater (95% confidence interval, 2.00 to 3.19) with warfarin than they were with enoxaparin. Major hemorrhage occurred in four warfarin-treated patients and nine enoxaparin-treated patients; with the numbers available, this difference was not significant (p = 0.17). Clinically important operative-site hemorrhage occurred in six (3%) of the warfarin-treated patients and twelve (7%) of the enoxaparin-treated patients (p = 0.15). CONCLUSIONS: A fixed 30-mg subcutaneous dose of enoxaparin, administered twice daily, with the first dose administered within eight hours after the completion of surgery, was significantly more effective than adjusted-dose warfarin in reducing the occurrence of asymptomatic venous thromboembolism, including proximal deep-vein thrombosis, in patients undergoing total knee arthroplasty. With the numbers available, there was no significant difference between groups with regard to the occurrence of major hemorrhagic complications; however, the rate of overall hemorrhagic complications was higher in the enoxaparin group.