Prophylaxis of postoperative thromboembolism with low molecular weight heparins

Primary prevention of venous thromboembolism with low molecular weight heparins in surgical patients – 2024: Council of Experts resolution

On March 15, 2024, in Moscow, the Russian Phlebological Association and the National Association of Specialists in Thrombosis, Clinical Hemostasiology and Hemorheology organized a meeting of the Council of Experts during the Russian Forum on Thrombosis and Hemostasis on the acute issues of venous thromboembolism (VTE) primary prevention using low molecular weight heparins (LMWH) in surgical patients with different body weight. The participants reviewed the relevance and prevalence of this problem in surgical practice, discussed risk factors and the frequency of VTE development, including bleeding in the postoperative period, and the Caprini risk score for complications. The discussion also focused on standard and personalized LMWH doses for primary prophylaxis of VTE in the perioperative period in surgical patients, depending on body weight, and the role of laboratory tests, including assessment of LMWH anti-Xa activity for monitoring the efficacy and safety of VTE primary prevention in clinical practice.

Thromboprophylaxis across orthopaedic surgery: Bibliometric analysis of the most cited articles

PURPOSE

One of the most common adverse events after orthopaedic surgery, with a potential for subsequent serious morbidity and mortality is venous thromboembolism (VTE). Bibliometric analysis has been performed regarding many topics and across orthopaedics. As DVT prophylaxis is a major component of both orthopaedic surgery considerations and research, a bibliometric analysis in this area would prove beneficial in not only in understanding the research done in the field thus far, but would also direct future research efforts.

METHODS

The Web of Science (WoS) database from the Institute of Scientific Information (ISI) was used to compile articles for bibliometric analysis using Boolean search: ((Orthopaedic∗ OR Orthopaedic∗) AND (thromboprophylaxis OR Thromboembolism OR Deep vein thrombosis OR thrombus OR embolism OR anticoagulation OR Embolus OR prophylaxis)).

RESULTS

The Top 100 cited articles included in the final list generated a total of 21,099 citations. The highest cited article was Prevention of venous thromboembolism by Geerts et al. published in Chest, which had a total of 2802 on WoS, and a calculated citation density of 215.54 of citations/years since publication. Comparing the overall citation against the year of publication there was a slight positive trend favoring more recent publications (R-value: 0.142; adjusted R-squared: 0.01; p = 0.16). Analysis of an articles Level of Evidence (LOE), 17 were grade with a level of I.

CONCLUSIONS

Orthopaedic thromboprophylaxis is an ever-changing field that is at the forefront of orthopaedic literature. The significant trend favoring high quality research within orthopaedic thromboprophylaxis demonstrates the importance of this topic and there was a need for a guide to best understand the evolution of DVT prophylaxis.

Venous Thromboembolism Incidence and Prophylaxis Use After Gastrectomy Among Korean Patients With Gastric Adenocarcinoma: The PROTECTOR Randomized Clinical Trial

Importance

The guidelines by the National Comprehensive Cancer Network and the American Society for Clinical Oncology recommend the routine use of thromboprophylaxis for patients with gastric adenocarcinoma. However, many physicians in Asian countries use venous thromboembolism (VTE) prophylaxis much less often because of the perceived lower VTE incidence in this population.

Objectives

To evaluate the incidence of postgastrectomy VTE in Korean patients with gastric adenocarcinoma, and to identify the complications and evaluate the efficacy and safety of VTE prevention methods.

Design, Setting, and Participants

The Optimal Prophylactic Method for Venous Thromboembolism After Gastrectomy in Korean Patients (PROTECTOR) randomized clinical trial was conducted between August 1, 2011, and March 31, 2015. Patients with histologically confirmed gastric adenocarcinoma presenting to a single center (Seoul St Mary's Hospital in Seoul, South Korea) were enrolled. Patients were randomized to either an intermittent pneumatic compression (IPC)-only group or an IPC+low-molecular-weight (LMW) heparin sodium group. The data were analyzed on intention-to-treat and per protocol bases. Data analysis was performed from April 1, 2016, to October 30, 2017.

Main Outcomes and Measures

Venous thromboembolism incidence was the primary outcome. Postoperative complications, particularly those associated with VTE prophylaxis methods, were the secondary end point.

Results

Of the 682 patients enrolled and randomized, 447 (65.5%) were male and 245 (34.5%) were female, with a mean (SD) age of 57.67 (12.94) years. Among the 666 patients included in the analysis, the overall incidence of VTE was 2.1%. The incidence of VTE was statistically significantly higher in the IPC-only group compared with the IPC+LMW heparin group (3.6%; 95% CI, 2.05%-6.14% vs 0.6%; 95% CI, 0.17%-2.18%; P = .008). Among the 14 patients (2.1%) with VTE, 13 were asymptomatic and received a deep vein thrombosis diagnosis, whereas 1 patient received a symptomatic pulmonary thromboembolism diagnosis. The overall incidence of bleeding complications was 5.1%. The incidence of bleeding complications was significantly higher in the IPC+LMW heparin group compared with the IPC-only group (9.1% vs 1.2%; P < .001). No cases of VTE-associated mortality were noted.

Conclusions and Relevance

Use of IPC alone is inferior to the use of IPC+LMW heparin in preventing postoperative VTE. Because LMW heparin is associated with a high bleeding risk, further study is needed to stratify the patients at high risk for perioperative development of VTE.

Trial Registration

ClinicalTrials.gov Identifier: NCT01448746.

Prolonged thromboprophylaxis with low molecular weight heparin for abdominal or pelvic surgery

BACKGROUND

This an update of the review first published in 2009.Major abdominal and pelvic surgery carries a high risk of venous thromboembolism (VTE). The efficacy of thromboprophylaxis with low molecular weight heparin (LMWH) administered during the in-hospital period is well-documented, but the optimal duration of prophylaxis after surgery remains controversial. Some studies suggest that patients undergoing major abdominopelvic surgery benefit from prolongation of the prophylaxis up to 28 days after surgery.

OBJECTIVES

To evaluate the efficacy and safety of prolonged thromboprophylaxis with LMWH for at least 14 days after abdominal or pelvic surgery compared with thromboprophylaxis administered during the in-hospital period only in preventing late onset VTE.

SEARCH METHODS

We performed electronic searches on 28 October 2017 in the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, LILACS and registered trials (Clinicaltrials.gov October 28, 2017 and World Health Organization International Clinical Trials Registry Platform (ICTRP) 28 October 2017). Abstract books from major congresses addressing thromboembolism were handsearched from 1976 to 28 October 2017, as were reference lists from relevant studies.

SELECTION CRITERIA

We assessed randomized controlled clinical trials (RCTs) comparing prolonged thromboprophylaxis (≥ fourteen days) with any LMWH agent with placebo, or other methods, or both to thromboprophylaxis during the admission period only. The population consisted of persons undergoing abdominal or pelvic surgery for both benign and malignant pathology. The outcome measures included VTE (deep venous thrombosis (DVT) or pulmonary embolism (PE)) as assessed by objective means (venography, ultrasonography, pulmonary ventilation/perfusion scintigraphy, spiral computed tomography (CT) scan or autopsy). We excluded studies exclusively reporting on clinical diagnosis of VTE without objective confirmation.

DATA COLLECTION AND ANALYSIS

Review authors identified studies and extracted data. Outcomes were VTE (DVT or PE) assessed by objective means. Safety outcomes were defined as bleeding complications and mortality within three months after surgery. Sensitivity analyses were also performed with unpublished studies excluded, and with study participants limited to those undergoing solely open and not laparoscopic surgery. We used a fixed-effect model for analysis.

MAIN RESULTS

We identified seven RCTs (1728 participants) evaluating prolonged thromboprophylaxis with LMWH compared with control or placebo. The searches resulted in 1632 studies, of which we excluded 1528. One hundred and four abstracts, eligible for inclusion, were assessed of which seven studies met the inclusion criteria.For the primary outcome, the incidence of overall VTE after major abdominal or pelvic surgery was 13.2% in the control group compared to 5.3% in the patients receiving out-of-hospital LMWH (Mantel Haentzel (M-H) odds ratio (OR) 0.38, 95% confidence interval (CI) 0.26 to 0.54; I2 = 28%; moderate-quality evidence).For the secondary outcome of all DVT, seven studies, n = 1728, showed prolonged thromboprophylaxis with LMWH to be associated with a statistically significant reduction in the incidence of all DVT (M-H OR 0.39, 95% CI 0.27 to 0.55; I2 = 28%; moderate-quality evidence).We found a similar reduction when analysis was limited to incidence in proximal DVT (M-H OR 0.22, 95% CI 0.10 to 0.47; I2 = 0%; moderate-quality evidence).The incidence of symptomatic VTE was also reduced from 1.0% in the control group to 0.1% in patients receiving prolonged thromboprophylaxis, which approached significance (M-H OR 0.30, 95% CI 0.08 to 1.11; I2 = 0%; moderate-quality evidence).No difference in the incidence of bleeding between the control and LMWH group was found, 2.8% and 3.4%, respectively (M-H OR 1.10, 95% CI 0.67 to 1.81; I2 = 0%; moderate-quality evidence).No difference in mortality between the control and LMWH group was found, 3.8% and 3.9%, respectively (M-H OR 1.15, 95% CI 0.72 to 1.84; moderate-quality evidence).Estimates of heterogeneity ranged between 0% and 28% depending on the analysis, suggesting low or unimportant heterogeneity.

AUTHORS' CONCLUSIONS

Prolonged thromboprophylaxis with LMWH significantly reduces the risk of VTE compared to thromboprophylaxis during hospital admittance only, without increasing bleeding complications or mortality after major abdominal or pelvic surgery. This finding also holds true for DVT alone, and for both proximal and symptomatic DVT. The quality of the evidence is moderate and provides moderate support for routine use of prolonged thromboprophylaxis. Given the low heterogeneity between studies and the consistent and moderate evidence of a decrease in risk for VTE, our findings suggest that additional studies may help refine the degree of risk reduction but would be unlikely to significantly influence these findings. This updated review provides additional evidence and supports the previous results reported in the 2009 review.

Prolonged thromboprophylaxis with low molecular weight heparin for abdominal or pelvic surgery

BACKGROUND

This an update of the review first published in 2009.Major abdominal and pelvic surgery carries a high risk of venous thromboembolism (VTE). The efficacy of thromboprophylaxis with low molecular weight heparin (LMWH) administered during the in-hospital period is well-documented, but the optimal duration of prophylaxis after surgery remains controversial. Some studies suggest that patients undergoing major abdominopelvic surgery benefit from prolongation of the prophylaxis up to 28 days after surgery.

OBJECTIVES

To evaluate the efficacy and safety of prolonged thromboprophylaxis with LMWH for at least 14 days after abdominal or pelvic surgery compared with thromboprophylaxis administered during the in-hospital period only in preventing late onset VTE.

SEARCH METHODS

We performed electronic searches on 28 October 2017 in the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, LILACS and registered trials (Clinicaltrials.gov October 28, 2017 and World Health Organization International Clinical Trials Registry Platform (ICTRP) 28 October 2017). Abstract books from major congresses addressing thromboembolism were handsearched from 1976 to 28 October 2017, as were reference lists from relevant studies.

SELECTION CRITERIA

We assessed randomized controlled clinical trials (RCTs) comparing prolonged thromboprophylaxis (≥ fourteen days) with any LMWH agent with placebo, or other methods, or both to thromboprophylaxis during the admission period only. The population consisted of persons undergoing abdominal or pelvic surgery for both benign and malignant pathology. The outcome measures included VTE (deep venous thrombosis (DVT) or pulmonary embolism (PE)) as assessed by objective means (venography, ultrasonography, pulmonary ventilation/perfusion scintigraphy, spiral computed tomography (CT) scan or autopsy). We excluded studies exclusively reporting on clinical diagnosis of VTE without objective confirmation.

DATA COLLECTION AND ANALYSIS

Review authors identified studies and extracted data. Outcomes were VTE (DVT or PE) assessed by objective means. Safety outcomes were defined as bleeding complications and mortality within three months after surgery. Sensitivity analyses were also performed with unpublished studies excluded, and with study participants limited to those undergoing solely open and not laparoscopic surgery. We used a fixed-effect model for analysis.

MAIN RESULTS

We identified seven RCTs (1728 participants) evaluating prolonged thromboprophylaxis with LMWH compared with control or placebo. The searches resulted in 1632 studies, of which we excluded 1528. One hundred and four abstracts, eligible for inclusion, were assessed of which seven studies met the inclusion criteria.For the primary outcome, the incidence of overall VTE after major abdominal or pelvic surgery was 13.2% in the control group compared to 5.3% in the patients receiving out-of-hospital LMWH (Mantel Haentzel (M-H) odds ratio (OR) 0.38, 95% confidence interval (CI) 0.26 to 0.54; I2 = 28%; moderate-quality evidence).For the secondary outcome of all DVT, seven studies, n = 1728, showed prolonged thromboprophylaxis with LMWH to be associated with a statistically significant reduction in the incidence of all DVT (M-H OR 0.39, 95% CI 0.27 to 0.55; I2 = 28%; moderate-quality evidence).We found a similar reduction when analysis was limited to incidence in proximal DVT (M-H OR 0.22, 95% CI 0.10 to 0.47; I2 = 0%; moderate-quality evidence).The incidence of symptomatic VTE was also reduced from 1.0% in the control group to 0.1% in patients receiving prolonged thromboprophylaxis (M-H OR 0.30, 95% CI 0.08 to 1.11; I2 = 0%; moderate-quality evidence).No difference in the incidence of bleeding between the control and LMWH group was found, 2.8% and 3.4%, respectively (M-H OR 1.10, 95% CI 0.67 to 1.81; I2 = 0%; moderate-quality evidence).No difference in mortality between the control and LMWH group was found, 3.8% and 3.9%, respectively (M-H OR 1.15, 95% CI 0.72 to 1.84; moderate-quality evidence).Estimates of heterogeneity ranged between 0% and 28% depending on the analysis, suggesting low or unimportant heterogeneity.

AUTHORS' CONCLUSIONS

Prolonged thromboprophylaxis with LMWH significantly reduces the risk of VTE compared to thromboprophylaxis during hospital admittance only, without increasing bleeding complications or mortality after major abdominal or pelvic surgery. This finding also holds true for DVT alone, and for both proximal and symptomatic DVT. The quality of the evidence is moderate and provides moderate support for routine use of prolonged thromboprophylaxis. Given the low heterogeneity between studies and the consistent and moderate evidence of a decrease in risk for VTE, our findings suggest that additional studies may help refine the degree of risk reduction but would be unlikely to significantly influence these findings. This updated review provides additional evidence and supports the previous results reported in the 2009 review.

Prolonged thromboprophylaxis with low molecular weight heparin for abdominal or pelvic surgery

BACKGROUND

This an update of the review first published in 2009.Major abdominal and pelvic surgery carries a high risk of venous thromboembolism (VTE). The efficacy of thromboprophylaxis with low molecular weight heparin (LMWH) administered during the in-hospital period is well-documented, but the optimal duration of prophylaxis after surgery remains controversial. Some studies suggest that patients undergoing major abdominopelvic surgery benefit from prolongation of the prophylaxis up to 28 days after surgery.

OBJECTIVES

To evaluate the efficacy and safety of prolonged thromboprophylaxis with LMWH for at least 14 days after abdominal or pelvic surgery compared with thromboprophylaxis administered during the in-hospital period only in preventing late onset VTE.

SEARCH METHODS

We performed electronic searches on 28 October 2017 in the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, LILACS and registered trials (Clinicaltrials.gov October 28, 2017 and World Health Organization International Clinical Trials Registry Platform (ICTRP) 28 October 2017). Abstract books from major congresses addressing thromboembolism were handsearched from 1976 to 28 October 2017, as were reference lists from relevant studies.

SELECTION CRITERIA

We assessed randomized controlled clinical trials (RCTs) comparing prolonged thromboprophylaxis (≥ fourteen days) with any LMWH agent with placebo, or other methods, or both to thromboprophylaxis during the admission period only. The population consisted of persons undergoing abdominal or pelvic surgery for both benign and malignant pathology. The outcome measures included VTE (deep venous thrombosis (DVT) or pulmonary embolism (PE)) as assessed by objective means (venography, ultrasonography, pulmonary ventilation/perfusion scintigraphy, spiral computed tomography (CT) scan or autopsy). We excluded studies exclusively reporting on clinical diagnosis of VTE without objective confirmation.

DATA COLLECTION AND ANALYSIS

Review authors identified studies and extracted data. Outcomes were VTE (DVT or PE) assessed by objective means. Safety outcomes were defined as bleeding complications within three months after surgery. Sensitivity analyses were also performed with unpublished studies excluded, and with study participants limited to those undergoing solely open and not laparoscopic surgery. We used a fixed-effect model for analysis.

MAIN RESULTS

We identified seven RCTs (1728 participants) evaluating prolonged thromboprophylaxis with LMWH compared with control or placebo. The searches resulted in 1632 studies, of which we excluded 1528. One hundred and four abstracts, eligible for inclusion, were assessed of which seven studies met the inclusion criteria.For the primary outcome, the incidence of overall VTE after major abdominal or pelvic surgery was 13.2% in the control group compared to 5.3% in the patients receiving out-of-hospital LMWH (Mantel Haentzel (M-H) odds ratio (OR) 0.38, 95% confidence interval (CI) 0.26 to 0.54; I2 = 28%; seven studies, n = 1728; moderate-quality evidence).For the secondary outcome of all DVT, seven studies, n = 1728, showed prolonged thromboprophylaxis with LMWH to be associated with a statistically significant reduction in the incidence of all DVT (M-H OR 0.39, 95% CI 0.27 to 0.55; I2 = 28%; moderate-quality evidence).We found a similar reduction when analysis was limited to incidence in proximal DVT (M-H OR 0.22, 95% CI 0.10 to 0.47; I2 = 0%; moderate-quality evidence).The incidence of symptomatic VTE was also reduced from 1.0% in the control group to 0.1% in patients receiving prolonged thromboprophylaxis (M-H OR 0.30, 95% CI 0.08 to 1.11; I2 = 0%; moderate-quality evidence).No difference in the incidence of bleeding between the control and LMWH group was found, 2.8% and 3.4%, respectively (HM-H OR 1.10, 95% CI 0.67 to 1.81; I2 = 0%; seven studies, n = 2239; moderate-quality evidence).Estimates of heterogeneity ranged between 0% and 28% depending on the analysis, suggesting low or unimportant heterogeneity.

AUTHORS' CONCLUSIONS

Prolonged thromboprophylaxis with LMWH significantly reduces the risk of VTE compared to thromboprophylaxis during hospital admittance only, without increasing bleeding complications after major abdominal or pelvic surgery. This finding also holds true for DVT alone, and for both proximal and symptomatic DVT. The quality of the evidence is moderate and provides moderate support for routine use of prolonged thromboprophylaxis. Given the low heterogeneity between studies and the consistent and moderate evidence of a decrease in risk for VTE, our findings suggest that additional studies may help refine the degree of risk reduction but would be unlikely to significantly influence these findings. This updated review provides additional evidence and supports the previous results reported in the 2009 review.

Early Preoperative Thromboprophylaxis with Klexane® in Hip Fracture Surgery: A Placebo-Controlled Study

The aim of this study was to evaluate any possible benefits of early thromboprophylactic treatment in the preven tion of deep vein thrombosis (DVT) in high-risk hip fracture patients. Within 30 months, 239 patients were included in a double-blind placebo-controlled study. With the diagnosis of hip fracture confirmed, patients received either 40-mg Enoxa parin s.c. or placebo once daily until operation. Postoperatively, all patients received 40-mg Enoxaparin s.c. once daily until phlebography. Phlebography was first performed on the oper ated leg, and with no thrombosis detected, the other leg was investigated as well. The two groups did not differ demograph ically. Eighty-five patients were excluded. Eight patients died during the study period. The remaining 146 patients had as cending phlebography performed and 24 patients (16.4%) de veloped DVT. Nine (12%) of 75 patients in the Klexane® and 15 (21 %) of 72 patients in the placebo group developed DVT. The risk ratio was 0.58 (95% confidence limits 0.27-1.25) and p = .15 (X2 test). There was no difference in perioperative bleeding or transfusion requirements. We conclude that Klex ane® is an effective and safe thromboprophylactic agent in hip fracture patients. Key Words: Hip fracture—Thrombopro phylaxis—Low—molecular heparin.

Risk of and Prophylaxis for Venous Thromboembolism in Hospital Patients

Objective:

To review the published clinical data on prophylaxis for thromboembolism in order to develop general guidelines to encourage the establishment of local protocols for management.

Data sources:

Published papers on thromboembolism over the period 1991–1997 were identified by Medline search and/or from the authors' personal literature collections and reviewed.

Study selection:

A total of 981 studies were identified. Only those papers reporting randomized studies with clearly defined diagnostic methods and clear end-points were included in this review.

Data extraction:

The available evidence for each specialty was summarized and reviewed by the authors responsible for each specialty, prior to presentation and discussion of their findings within the group. Where a consensus opinion was achieved in a speciality, general guidelines for thromboprophylaxis were summarized. Where a consensus could not be agreed, recommendations for further work were made.

Data synthesis:

There is evidence to support the preferred use of low-molecular-weight heparins (LMWHs) over unfractionated heparin (UFH) in orthopaedic surgery, major trauma and general surgery. However, the ideal duration of thromboprophylaxis has yet to be defined. The use of once daily subcutaneous administration of LMWH offers major practical advantages and may have significant cost saving implications. Further work is required to investigate the use of thromboprophylaxis in minimal access surgery, trauma, elective lower limb surgery, hip fracture and pregnancy; to compare the efficacy of LMWH and mechanical prophylaxis; and to investigate extended prophylaxis after discharge.

Conclusions:

There is overwhelming evidence that thromboembolic prophylaxis reduces the incidence of postoperative deep vein thrombosis and pulmonary embolism. Recommendations concerning the management of these patients when stratified into low, moderate and high risk are made with the suggestion that hospitals develop their own guidelines for the treatment of these patients.

Venous thromboembolism rates in patients with lower limb immobilization after Achilles tendon injury are unchanged after the introduction of prophylactic aspirin: audit

ESSENTIALS: We audited venous thromboembolism (VTE) in Achilles injuries after the use of prophylactic aspirin. We audited 218 patients with Achilles injury requiring lower limb immobilization for ≥ 1 week. Fourteen patients (6.4%, 95% CI 3.6% to 10.5%) developed symptomatic and confirmed VTE. The incidence was similar to the 6.3% identified in the same patient group prior to the use of aspirin.

BACKGROUND/OBJECTIVE

We report a follow-up audit of the incidence of venous thromboembolism (VTE) in patients requiring lower limb immobilization because of Achilles tendon injury, since the introduction of a policy to routinely prescribe 100 mg of aspirin daily.

PATIENTS/METHODS

We studied 218 patients aged 18-65 years who attended the Orthopaedic Assessment Unit at Wellington Hospital between January 2013 and December 2014 with Achilles tendon injury requiring lower limb immobilization for ≥ 1 week. Information on assessment of VTE risk, prescription of aspirin and symptomatic VTE occurring within 70 days of immobilization was obtained and compared with the same information collected with the same method in the same patient group between January 2006 and December 2007, before the policy to routinely prescribe aspirin was introduced.

RESULTS

A total of 189 of 218 (93%) patients were prescribed aspirin, as compared with 0.5% previously. Fourteen patients (6.4%, 95% confidence interval 3.6-10.5%) developed symptomatic radiologically confirmed VTE (10 distal deep vein thromboses [DVTs], two proximal DVTs, one pulmonary embolism [PE], and one PE with distal DVT). Aspirin was prescribed to all patients who subsequently developed a VTE; in one of 14, a recognized risk factor was documented. The VTE incidence was similar to the 6.3% identified in the previous audit.

CONCLUSION

Lower limb immobilization following Achilles tendon injury confers a high risk of VTE even with aspirin prophylaxis. Consideration should be given to prophylaxis with low molecular weight heparin during lower limb immobilization following Achilles tendon injury, as this has proven efficacy in this clinical situation.

The rate and mortality of postoperative venous thromboembolism of moderate risk surgery in Asian patients without thrombo-prophylaxis: systematic review with meta-analysis

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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 after surgery for benign prostatic hyperplasia

A systematic review has been performed on venous thromboembolism after surgery for benign prostatic hyperplasia. The risk of deep vein thrombosis is two to four times higher after open surgery than after transurethral resection. The risk after the newer transurethral methods (laser, radiofrequency, heat) is not known. Specific studies on thromboprophylaxis are few and have limited numbers of patients. Nonetheless, thromboprophylaxis (heparin) reduces the frequency of postoperative deep vein thrombosis after open surgery. Studies on patients undergoing transurethral resection are lacking. Antifibrinolytic treatment to diminish bleeding does not seem to increase the risk of thrombosis.

Incidence of pulmonary thromboembolism in gastric cancer surgery using routine thromboprophylaxis

BACKGROUND

There is a lack of published data on the incidence of pulmonary thromboembolism (PTE) after resections for gastric cancer. We report the incidence of PTE after gastric cancer surgery with routine thromboprophylaxis from a high-volume center.

METHODS

Between October 2002 and December 2008, 3262 patients underwent gastric cancer surgery with routine thromboprophylaxis using low-dose unfractionated heparin, intermittent pneumatic compression, fluid infusion, and graduated compression stockings. Patients diagnosed with PTE were identified from a prospectively collected database that included complications related to thromboprophylaxis.

RESULTS

Seven patients (0.2%) developed symptomatic PTE in this series. Multivariate analysis demonstrated that female sex (P = 0.029) and high body mass index (P = 0.025) were significant risk factors for PTE. The most common symptom was dyspnea (57%). Five patients (71%) developed PTE by the second postoperative day. All patients were treated successfully with medical treatment and no hospital deaths were recorded. Adverse events related to thromboprophylaxis included major postoperative bleeding in 10 (0.3%) of the 3262 patients. There were no cases of hematoma related to the insertion of epidural catheters for analgesia.

CONCLUSION

The routine use of thromboprophylaxis in Japanese patients undergoing gastric resection is safe and effective in reducing the incidence of pulmonary thromboembolism.

The effect of low molecular weight heparin thromboprophylaxis on bleeding complications after gastric cancer surgery

BACKGROUND

Low molecular weight heparin (LMWH) has been widely used to prevent venous thromboembolism in cancer surgical patients. However, relatively few studies have examined the safety aspects related to the use of LMWH after abdominal cancer surgery. This study was designed to investigate the relationship between bleeding complications and LMWH thromboprophylaxis after gastric cancer surgery.

METHODS

From March to July in 2009, 179 consecutive patients who underwent gastric cancer surgery at our institution were administered LMWH (3200 U once daily from 2 to 6 h before surgery until discharge) perioperatively. A total of 182 patients consecutively treated before the introduction of LMWH prophylaxis were selected as controls.

RESULTS

There were 234 men and 127 women (mean age, 60 +/- 12 years). No significant intergroup differences were observed with respect to clinicopathological features and operative procedures. No patient in the LMWH or control group developed symptomatic venous thromboembolism postoperatively. However, the LMWH group had a significantly higher surgical complication rate (27.4 versus 15.4%, P = 0.005). Among the surgical complications, postoperative bleeding and wound complications were significantly higher in the LMWH group, whereas other complications were similar in the two study groups. Multivariate analysis showed that LMWH administration was an independent risk factor (odds ratio, 2.83; 95% confidence interval, 1.28-6.23, P = 0.009) of postoperative bleeding.

CONCLUSIONS

LMWH thromboprophylaxis was found to increase significantly the risk of bleeding complications after gastric cancer surgery. Optimal LMWH prophylaxis regimens, including the dosage and timing of treatment commencement, for gastric cancer surgery should be determined in further clinical trials.

[Venous thromboembolic disease in general surgery]

About one-fourth of patients undergoing general surgery and not receiving antithrombotic prophylaxis will suffer postoperative venous thromboembolism (VTE), which includes deep vein thrombosis (DVT) of the legs and pulmonary embolism (PE). Apart from fatal PE, which affects 0.8% of general surgical patients, about one-third of patients with DVT will develop long-term complications, such as posthrombotic syndrome and recurrent VTE. The best strategy to reduce the high morbidity and mortality associated with postoperative VTE, is to use some of the available prophylactic methods which have been shown to be effective and safe for VTE prevention. The most widely investigated and implemented methods in western countries are the pharmacological agents, namely heparin and their low molecular weight fractions, as well as mechanical methods, such as elastic stockings and intermittent pneumatic compression of the legs. Appropriate prophylaxis measures should be implemented according to the characteristics of each patient and the surgical operation to be done.

Prolonged thromboprophylaxis with low molecular weight heparin for abdominal or pelvic surgery

BACKGROUND

Major abdominal and pelvic surgery carries a high risk of venous thromboembolism (VTE). The efficacy of thromboprophylaxis with low-molecular weight heparin (LMWH) administered during the in-hospital period is well documented, but the optimal duration of thromboprophylaxis after surgery remains controversial. Some studies suggest that patients undergoing major abdominal surgery benefit from prolongation of the thromboprophylaxis to 1 month after surgery. No systematic review on prolonged thromboprophylaxis after major abdominal or pelvic surgery has been published.

OBJECTIVES

To evaluate the efficacy and safety of prolonged thromboprophylaxis with LMWH for at least 1 month after abdominal or pelvic surgery with thromboprophylaxis administered during the in-hospital period only in preventing late VTE.

SEARCH STRATEGY

Electronic searches were performed January 2008 in the Medline, Embase, Lilacs, and the Cochrane Central Register of Controlled Trials. Abstract books from major congresses addressing thromboembolism were hand searched, as were reference lists from studies of relevance.

SELECTION CRITERIA

We assessed both randomised and non-randomised controlled clinical trials comparing prolonged thromboprophylaxis with any anti-thrombotic agent with placebo and/or thromboprophylaxis during the admission period only. The patient population in the trials were patients undergoing abdominal or pelvic surgery. The outcome measures included VTE (deep venous thrombosis (DVT) or pulmonary embolism (PE)) as assessed by objective means (ascending bilateral venography, ultrasonography, pulmonary ventilation/perfusion scintigraphy, spiral CT scan or autopsy). Studies exclusively reporting on clinical diagnosis of VTE, without objective confirmation were excluded.

DATA COLLECTION AND ANALYSIS

The identification of studies and data extraction were performed by the authors. Outcomes were VTE (DVT or PE) assessed by objective means. Safety outcome were defined as bleeding complications and mortality within 3 months after surgery.

MAIN RESULTS

The search exclusively detected trials evaluating prolonged thromboprophylaxis with LMWH as compared to control or placebo. 133 studies were found in the searches, of which only 4 were found eligible for inclusion, and 129 were excluded. The incidence of overall VTE after major abdominal or pelvic surgery was 14.3% (95% confidence interval 11.2% - 17.8%) in the control group as compared to 6.1% (95% CI 4.0% - 8.7%) in the patients receiving out-of-hospital LMWH. This difference was statistically significant, Peto Odds Ratio 0.41 (95% CI 0.26 -0.63), P < 0.0005. Prolonged thromboprophylaxis with LMWH was also associated with a statistically significant reduction of even the incidence of symptomatic VTE from 1.7% (95% CI 0.8% - 3.4%) in the control group to 0.2 % (95% CI 0.0% - 1.2%) in patients receiving prolonged thromboprophylaxis, Peto Odds ratio 0.22 (95% CI 0.06 -0.80), P = 0.02. The respective incidence of bleeding in the control and LMWH group were 3.7% (95% CI 2.4% -5.5%) and 4.1% (95% CI 2.7% - 6.0%), Peto Odds ratio 1.11 (95% CI 0.62 - 1.97), P = 0.73. There was no significant heterogeneity detected as regards to outcome parameters reported in the included trials.

AUTHORS' CONCLUSIONS

Prolonged thromboprophylaxis with LMWH significantly reduces the risk of VTE compared to thromboprophylaxis during hospital admittance only, without increasing bleeding complications after major abdominal or pelvic surgery.

A survey of inguinal hernia repair in Wales with special emphasis on laparoscopic repair

BACKGROUND

The National Institute of Clinical Excellence (NICE) recently published its guidance on the use of laparoscopic repair for inguinal hernias. This study aimed to assess the likely uptake of laparoscopic surgery for inguinal hernias in Wales. In addition the current practice with regards to day case surgery, use of local anaesthesia, antibiotic prophylaxis, thromboembolic prophylaxis and advice regarding convalescence was assessed.

METHODS

A postal questionnaire survey of all consultant surgeons (n = 91) in Wales was performed.

RESULTS

There was a 70% (n = 67) response to the questionnaire. Fifteen percent of surgeons (n = 9) perform laparoscopic inguinal hernia repair in Wales; 10% of surgeons in Wales agreed with the NICE guidance. Lichtenstein hernia repair was the most commonly used the technique to repair primary inguinal hernias in Wales (82%). No surgeon currently is using a laparoscopic repair as the technique of choice for repair of primary inguinal hernias. Eighteen percent of surgeons perform all the procedures as day cases; 15% of surgeons perform more than 90% of the procedures under local anaesthesia; 44% of surgeons do not use any form of thromboprophylaxis for elective inguinal hernia repair, while 78% of the surgeons used routine antibiotic prophylaxis. Post-operative advice regarding return to sedentary work and driving was highly variable (1-4 weeks), as was advice regarding heavy work and sport (2-12 weeks).

CONCLUSIONS

The uptake of laparoscopic surgery for inguinal hernia repair in Wales is low. Only a minority of surgeons agree with the NICE guidance. Similarly the uptake of day case repair and the use of local anaesthesia are minimal. The use of antibiotic and thromboembolic prophylaxis is empirical and inconsistent. There is a need for evidence-based guidelines to standardise the antibiotic prophylaxis, TE prophylaxis and advice regarding post-operative advice.

Prevention of venous thromboembolism in surgical patients with breast cancer

Background

No randomized trial has yet studied venous thromboembolism (VTE) prophylaxis in patients undergoing surgery for breast cancer.

Methods

Relevant articles were identified using Medline searches. Secondary articles were identified from the reference lists of key papers.

Results and conclusion

The absence of randomized trials comparing different methods of VTE prophylaxis with controls makes an evidence-based consensus among breast cancer surgeons difficult. Intermittent pneumatic compression (IPC) and graduated compression (GC) are effective in reducing VTE without the haemorrhagic complications associated with heparin; their effects are additive. The authors suggest the following strategy. All patients undergoing surgery for breast cancer should receive both IPC and GC, with heparin reserved for those at very high risk. A controlled trial should randomize women to receive heparin or not, and all women should have both IPC and GC. The primary endpoints should be the development of VTE and/or haemorrhagic complications.

Mechanical and pharmacological methods to prevent venous thromboembolism

Today, it is possible to define certain risk groups for the development of venous thromboembolism, most studies having been conducted on post-operative venous thromboembolism. Nonetheless, the risk classification is rather inexact, resulting in many patients receiving prophylaxis who would not have gone on to develop the complication. However, the current prophylactic methods are safe and can therefore also be used in the post-operative situation. The dominating pharmacological substances are unfractionated heparin, low-molecular-weight heparins and the pentasaccharide fondaparinux. In some situations (such as elective hip surgery and likely hip fracture surgery, and in many cases where malignant diseases in the abdomen/pelvis have been operated upon), extended prophylaxis for 1 month should be considered.

Profilaxia para tromboembolismo venoso em um hospital de ensino

OBJETIVO: Verificar se a profilaxia da trombose venosa profunda está sendo utilizada de maneira correta e rotineira em um hospital de ensino. MÉTODOS E CASUÍSTICA: Foi realizado um estudo transversal de pacientes internados em sete setores (enfermarias) do Conjunto Hospitalar de Sorocaba (Hospital de Ensino), no período de agosto de 2004 a agosto de 2005. Para estratificação do risco de trombose venosa profunda de cada paciente, foram pesquisados fatores clínicos e cirúrgicos, segundo o protocolo preconizado pela Sociedade Brasileira de Angiologia e Cirurgia Vascular. No período estudado, foram analisados 216 prontuários, dos quais 30 eram da cirurgia abdominal, 30 da cirurgia vascular, 30 da urologia, 31 da clínica médica, 31 da unidade de terapia intensiva, 31 da ortopedia e 33 da ginecologia/obstetrícia. RESULTADOS: Do total de pacientes, foi efetuada profilaxia para trombose venosa profunda em 57 (26%), sendo que, em 51 (89%), a execução foi de maneira correta e, em 6 (11%), não-preconizada. O método profilático mais utilizado foi o medicamentoso; 49 de 57 pacientes fizeram uso de heparina de baixo peso molecular. Também foi verificada a utilização de meias elásticas em cinco pacientes e deambulação precoce em sete. Já a compressão pneumática intermitente não foi utilizada em nenhum deles. CONCLUSÃO: De acordo com os resultados e com base no protocolo, concluiu-se que, no período da pesquisa, a profilaxia para trombose venosa profunda, no Conjunto Hospitalar de Sorocaba, foi executada rotineiramente e de forma adequada em apenas 23,6% (51 do total de 216 pacientes).

Oral heparin: status review

Unfractionated heparin and low molecular weight heparin are the most commonly used antithrombotic and thromboprophylactic agents in hospital practice. Extended out-of-hospital treatment is inconvenient in that these agents must be administered parenterally. Current research is directed at development of a safe and effective oral antithrombotic agent as an alternative for the effective, yet difficult to use vitamin K antagonists. A novel drug delivery technology that facilitates transport of drugs across the gastrointestinal epithelium has been harnessed to develop an oral dosage form of unfractionated heparin. Combining unfractionated heparin with the carrier molecule, sodium N-(8 [2-hydroxybenzoyl]amino) caprylate, or SNAC has markedly increased the gastrointestinal absorption of this drug. Preclinical and clinical studies to-date suggests that oral heparin-SNAC can confer a clinical efficacious effect; further confirmation is sought in planned clinical trials.

Low-molecular-weight heparin for the prevention of postoperative venous thromboembolism after abdominal surgery: a review

PURPOSE OF REVIEW

To analyze the effect of low-molecular-weight heparin in abdominal surgery, which carries a significant risk of thrombosis, a risk further increased by cancer.

RECENT FINDINGS

Searches in EMBASE and PubMed between 1980 and 2004 were conducted to identify studies of thromboprophylaxis in abdominal surgery patients. Sixteen comparative studies were identified. They showed that low-molecular-weight heparin is as effective as unfractionated heparin in reducing venous thromboembolism and, at appropriate doses, can reduce bleeding complications. In very-high-risk cancer patients, a higher dose of low-molecular-weight heparin may offer increased efficacy without increasing the risk of bleeding. Extending the standard 7-10-day low-molecular-weight heparin prophylaxis period may benefit certain high-risk patient groups.

SUMMARY

Patients undergoing abdominal surgery should be stratified according to thromboembolism risk and given prophylaxis accordingly. Low-molecular-weight heparin is a recommended alternative to unfractionated heparin in moderate- or high-risk patients. In patients with cancer, high doses of low-molecular-weight heparin may offer increased efficacy without increased bleeding, and an extended 4-week period of prophylaxis could be beneficial.

Continuous passive motion in the prevention of deep-vein thrombosis: a randomised comparison in trauma patients

There is a high risk of venous thromboembolism when patients are immobilised following trauma. The combination of low-molecular-weight heparin (LMWH) with graduated compression stockings is frequently used in orthopaedic surgery to try and prevent this, but a relatively high incidence of thromboembolic events remains. Mechanical devices which perform continuous passive motion imitate contractions and increase the volume and velocity of venous flow. In this study 227 trauma patients were randomised to receive either treatment with the Arthroflow device and LMWH or only with the latter. The Arthroflow device passively extends and plantarflexes the feet. Patients were assessed initially by venous-occlusion plethysmography, compression ultrasonography and continuous wave Doppler, which were repeated weekly without knowledge of the category of randomisation. Those who showed evidence of deep-vein thrombosis underwent venography for confirmation. The incidence of deep-vein thrombosis was 25% in the LMWH group compared with 3.6% in those who had additional treatment with the Arthroflow device (p < 0.001). There were no substantial complications or problems of non-compliance with the Arthroflow device. Logistic regression analysis of the risk factors of deep-vein thrombosis showed high odds ratios for operation (4.1), immobilisation (4.3), older than 40 years of age (2.8) and obesity (2.2).

Systematic review of thromboprophylaxis in colorectal surgery -- an update

OBJECTIVE

The incidence of thromboembolism after colorectal surgery is higher than after general surgery. The aim of this paper is to update a systematic review addressing thrombosis prophylaxis in connection with colorectal surgery.

METHODS

MEDLINE, EMBASE, LILACS, abstract books and reference lists from reviews were searched without language restrictions for randomized controlled trials or clinical controlled trials comparing prophylactic interventions and/or placebo up til August 2003. Five hundred and fifty-eight studies were identified of which 19 fulfilled the inclusion criteria. Data extraction was done by at least two of the authors. Outcome was deep venous thrombosis and/or pulmonary embolism diagnosed by various methods.

RESULTS

Any kind of heparin is better than no treatment or placebo (11 studies) with a Peto Odds ratio (POR) at 0.32 (95% CI 0.20-0.53). Unfractionated heparin and low molecular weight heparin (4 studies) were equally effective POR 1.01 (95% CI 0.67-1.52). The combination of graduated compression stockings and LMWH is better than LMWH alone (2 studies) with a POR at 4.17 (95% CI 1.37-12.70).

CONCLUSION

The optimal thromboprophylaxis in colorectal surgery is the combination of graduated compression stockings and low-dose unfractionated heparin or low molecular weight heparin.

Assessment of the Risk and the Prophylaxis of Venous Thromboembolism in Surgical Patients

This review article first deals with risk factors for developing postoperative venous thromboembolism. The various pharmacological prophylactic methods available today are summarized with focus on dominating method low molecular weight heparin and the two new ones, the Xa inhibitor fondaparinux and the IIa inhibitor ximelagatran, both approved in orthopaedic surgery. The optimal timing to start prophylaxis is between 2 hours before and 10 hours after surgery. Evidence is accumulating that some in risk groups prolonged prophylaxis is indicated, ie. elective hip surgery, probably hip fracture surgery and probably also patients operated on for abdominal/pelvic cancer.

Epidemiology of venous thromboembolism in Asian patients undergoing major orthopedic surgery without thromboprophylaxis. The SMART study

BACKGROUND

In Asian patients undergoing surgery, the incidence of venous thromboembolism (VTE) is thought to be low relative to Western patients, and the routine use of thromboprophylaxis is controversial.

OBJECTIVES

The aim of this work was to study the epidemiology of VTE in Asian patients undergoing orthopedic surgery without thromboprophylaxis.

PATIENTS AND METHODS

We performed a prospective observational study of a cohort of consecutive Asian patients hospitalized for total hip or knee replacement or hip fracture surgery without thromboprophylaxis. The primary study outcome was the incidence of the composite of symptomatic VTE or sudden death at hospital discharge. This outcome was also assessed at 1 month's follow-up.

RESULTS

Between April 2001 and July 2002, 2420 patients were enrolled. Median age was 68 years and the median duration of hospital stay was 13 days. The rate of symptomatic VTE or sudden death as notified by investigators was 2.3%[55 patients, 99% confidence interval (CI) 1.6, 3.2] and 1.2% (28 patients, 99% CI 0.7, 1.8) after adjudication by an independent committee. Chronic heart failure, varicose veins and a history of VTE were independent risk factors (P < 0.05) for the occurrence of the primary endpoint. At 1 month's follow-up, the incidence of adjudicated symptomatic VTE or sudden death was 1.5% (35/2264 patients).

CONCLUSION

In Asian patients, the incidence of symptomatic VTE after major orthopedic surgery is not low, consistent with the rates observed in Western countries. The use of thromboprophylaxis should be considered in Asian patients undergoing such high-risk surgical procedures.

Major bleeding rates after prophylaxis against venous thromboembolism: Systematic review, meta-analysis, and cost implications

Objectives: The frequency and consequences of major bleeding associated with anticoagulant prophylaxis for prevention of venous thromboembolism is examined.

Methods: We conducted a systematic review and meta-analysis of controlled trials that reported rates of major bleeding after pharmaceutical thromboprophylaxis in patients undergoing major orthopedic surgery. Thromboprophylactic agents were divided into four groups:warfarin/other coumarin derivatives (WARF), unfractionated heparin (UFH), low molecular weight heparin (LMWH), and pentasaccharide (PS). Meta-analysis was conducted comparing LMWH with each of WARF, UFH, and PS. The frequency of re-operation due to major bleeding was reviewed and combined with published costs to estimate the mean cost of managing major bleeding events in these patients.

Results: Twenty-one studies including 20,523 patients met inclusion criteria for the meta-analysis. No evidence of significant between-trial heterogeneity in risk ratios was found. Combined (fixed effects) relative risks (RR) of major bleeding compared with LMWH were WARF – RR 0.59 (95 percent confidence interval [CI], 0.44–0.80); UFH – RR 1.52 (95 percent CI, 1.04–2.23); PS – RR 1.52 (95 percent CI, 1.11–2.09). Seventy-one studies including 32,433 patients were included in the review of consequences of major bleeding. We estimated that the average cost of major bleeding is $113 per patient receiving thromboprophylaxis.

Conclusions: LMWH results in fewer major bleeding episodes than UFH and PS but more than WARF. These events are costly and clinically important.

Prevention of venous thromboembolism: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy

This article discusses the prevention of venous thromboembolism (VTE) and is part of the Seventh American College of Chest Physicians Conference on Antithrombotic and Thrombolytic Therapy: Evidence-Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this chapter are the following. We recommend against the use of aspirin alone as thromboprophylaxis for any patient group (Grade 1A). For moderate-risk general surgery patients, we recommend prophylaxis with low-dose unfractionated heparin (LDUH) (5,000 U bid) or low-molecular-weight heparin (LMWH) [< or = 3,400 U once daily] (both Grade 1A). For higher risk general surgery patients, we recommend thromboprophylaxis with LDUH (5,000 U tid) or LMWH (> 3,400 U daily) [both Grade 1A]. For high-risk general surgery patients with multiple risk factors, we recommend combining pharmacologic methods (LDUH three times daily or LMWH, > 3,400 U daily) with the use of graduated compression stockings and/or intermittent pneumatic compression devices (Grade 1C+). We recommend that thromboprophylaxis be used in all patients undergoing major gynecologic surgery (Grade 1A) or major, open urologic procedures, and we recommend prophylaxis with LDUH two times or three times daily (Grade 1A). For patients undergoing elective total hip or knee arthroplasty, we recommend one of the following three anticoagulant agents: LMWH, fondaparinux, or adjusted-dose vitamin K antagonist (VKA) [international normalized ratio (INR) target, 2.5; range, 2.0 to 3.0] (all Grade 1A). For patients undergoing hip fracture surgery (HFS), we recommend the routine use of fondaparinux (Grade 1A), LMWH (Grade 1C+), VKA (target INR, 2.5; range, 2.0 to 3.0) [Grade 2B], or LDUH (Grade 1B). We recommend that patients undergoing hip or knee arthroplasty, or HFS receive thromboprophylaxis for at least 10 days (Grade 1A). We recommend that all trauma patients with at least one risk factor for VTE receive thromboprophylaxis (Grade 1A). In acutely ill medical patients who have been admitted to the hospital with congestive heart failure or severe respiratory disease, or who are confined to bed and have one or more additional risk factors, we recommend prophylaxis with LDUH (Grade 1A) or LMWH (Grade 1A). We recommend, on admission to the intensive care unit, all patients be assessed for their risk of VTE. Accordingly, most patients should receive thromboprophylaxis (Grade 1A).

Low molecular weight heparin for the prevention of venous thromboembolism after abdominal surgery

Background

Abdominal surgery carries a significant risk of venous thrombosis, a risk further increased in patients with cancer.

Methods

Embase and Pubmed searches between 1980 and 2003, using the key words ‘heparin,’ ‘surgery,’ ‘abdominal or rectal or colorectal or rectum or colon’ and ‘clinical trial’, were conducted to identify studies of thromboprophylaxis in patients having abdominal surgery.

Results

A total of 16 comparative studies were identified. These show that low molecular weight heparin (LMWH) is as effective as unfractionated heparin (UFH) in reducing venous thromboembolism after abdominal surgery and, at appropriate doses, can reduce bleeding complications. In very high-risk patients, a higher dose of LMWH may offer increased efficacy without increasing bleeding risk. Extending the standard 7–10-day period of prophylaxis may benefit certain high-risk groups; recent data show a significant benefit of 4-week enoxaparin thromboprophylaxis compared with a standard regimen, at no cost to safety.

Conclusion

Patients undergoing abdominal surgery should be stratified according to thromboembolism risk and managed accordingly. LMWH is a recommended alternative to UFH in moderate- or high-risk patients. In patients with cancer, high doses of LMWH may offer increased efficacy without increasing the bleeding risk and an extended 4-week period of prophylaxis appears beneficial.

Venous thromboembolism in intensive care patients

Venous thromboembolism frequently complicates the management of patients with severe medical and surgical illnesses. Because the diagnosis of VTE is especially challenging in critically ill patients, the focus of intensivists should be on characterization of risk factors and the appropriate choice of VTE prophylaxis. LDUH or LMHW is the preferred choice for VTE prophylaxis in ICU patients. Mechanical methods of prophylaxis should be reserved for patients with a high risk for bleeding. The effectiveness of mechanical methods and of combined strategies of prevention and the clinically important outcomes of therapy need to be explored further in critically ill patients. Few diagnostic strategies have been assessed in ICU patients with suspected PE. Ventilation-perfusion lung scans remain a pivotal diagnostic test but retain the same limitations in critically ill patients as seen in other patient populations. Newer noninvasive techniques, such as spiral CT associated with imaging of the extremities, are gaining more wide-spread use, but, thus far, pulmonary angiography remains the most reliable technique to confirm or exclude PE in patients with respiratory failure. A consensus must be reached regarding the most appropriate combination of tests for adequate and cost-effective diagnosis of VTE. Further investigation of diagnostic strategies that include adequate consideration of clinical diagnosis using standardized models and noninvasive imaging are warranted.

Low molecular weight heparin for venous thromboembolism prophylaxis in urologic oncologic surgery

OBJECTIVES

This is a prospective study in the use of low molecular weight heparin (LMWH) for venous thromboembolism prophylaxis in the previously unstudied subset of patients undergoing elective urologic cancer surgery.

METHODS

Thirty-eight patients undergoing elective urologic surgery were studied. Thirty-six had urologic malignancies. Pre-operative risk factors for venous thromboembolic disease were recorded. All patients received LMWH (dalteparin, Fragmin; Pharmacia, Stockholm, Sweden) subcutaneously on a daily basis beginning 1-2 hr before surgery and lasting for 3-7 days. Postoperative physical examination was used to check for clinical evidence of deep venous thrombosis (DVT). Clinical parameters such as physical examination and radiological testing were used to assess for evidence of DVT. Other data included intraoperative blood loss, transfusion requirements, postoperative bleeding complications, postoperative hematocrit and coagulation profiles, and local complications related to the subcutaneous injection of the LMWH.

RESULTS

All patients completed the prophylaxis protocol. None developed DVT. Mean intraoperative blood loss was 735 mL and 12 patients received an average of 1 unit of blood transfusion. No unusual hemorrhagic events were noted intra- or post-operatively. No reactions to the LMWH were noted. Average hematocrit of postoperative day 3 was 30.7 and platelet count and coagulation profiles remained normal postoperatively.

CONCLUSIONS

Low molecular weight heparins appear promising for DVT prophylaxis in high-risk urology patients.

Effectiveness and safety of bemiparin versus low-molecular weight heparins in orthopaedic surgery

OBJECTIVE

To evaluate the effectiveness and safety of bemiparin in the prophylaxis of thromboembolism in orthopaedic surgery with respect to other low-molecular-weight heparins.

METHODS

A meta-analysis of effectiveness and safety of low-molecular weight heparins versus standard heparin in orthopaedic surgery was performed. A literature search was done of Medline and Excerpta Medica from 1988 to 1998. Only controlled clinical trials were selected for meta-analysis. Differences between groups were expressed as odds ratios and these were combined by the Mantel-Haenszel method.

MAIN OUTCOME MEASURES

Rates of deep vein thrombosis, pulmonary embolism and wound haematoma.

RESULTS

Twenty-one studies involving 4605 patients were included in the meta-analysis. Bemiparin significantly reduces the rates of deep vein thrombosis (OR; 95% CI = 0.38, 0.15-0.90). No significant differences were found in pulmonary embolism and wound haematoma. The incidence of deep vein thrombosis is also lower with enoxaparin than with unfractionated heparin. However, only nadroparin reduced the incidence of pulmonary embolism (ORs = 0.24, 95% CI = 0.05-0.94). In any case, the incidence of wound haematoma was not significant.

CONCLUSION

Bemiparin seems to be as effective and safe as the other low-molecular-weight heparins in the prevention of thromboembolic complications in orthopaedic surgery.

Changing patterns of pharmacological thromboprophylaxis use by orthopaedic surgeons in New Zealand

BACKGROUND

A survey conducted in 1992 found that New Zealand orthopaedic surgeons relied on non-pharmacological methods of deep vein thrombosis prevention in most arthroplasty patients and almost all hip fracture patients. This survey was repeated in 1999 to ascertain whether this pattern of use had changed.

METHODS

All orthopaedic consultants in New Zealand who performed hip or knee surgery in 1999 were asked to complete a one-page postal questionnaire, asking for information regarding: the frequency with which chemoprophylaxis was employed in patients undergoing surgery for hip fracture, hip arthroplasty, or knee arthroplasty; the drug regimes used; the factors that influenced the choice of chemoprophylaxis;and the factors that limited chemoprophylaxis use in orthopaedic practice.

RESULTS

Between 1992 and 1999, the proportion of patients given chemoprophylaxis increased from 3% to 25% for patients with hip fracture, and from 32% to 57% for elective arthroplasty patients. The proportion of surgeons using low molecular weight heparin increased over the 7-year period from 55% to 76%,while aspirin use remained stable at 7% and standard heparin and warfarin decreased to less than 5%. There was a shift away from starting chemoprophylaxis preoperatively towards continuing until discharge, rather than until the patient was mobile. Opinions on indications and contraindications for chemoprophylaxis had not changed substantially during the 7-year period.

CONCLUSIONS

Orthopaedic surgeons' use of chemoprophylaxis has increased in New Zealand. However, since hospital stays have decreased considerably and most orthopaedic patients are now discharged within a fortnight,prophylaxis may now cover a shorter duration of the at-risk period.

Enoxaparin: a pharmacoeconomic review of its use in the prevention and treatment of venous thromboembolism and in acute coronary syndromes

The pharmacoeconomics of the low molecular weight heparin (LMWH) enoxaparin in the prophylaxis and treatment of venous thromboembolism have mostly been investigated in cost-effectiveness studies that estimated direct costs associated with treatment, using decision analyses and clinical outcome data from randomised controlled trials. These studies have shown enoxaparin to be cost effective compared with unfractionated heparin (UFH) and warfarin in short-term thromboprophylaxis for hospital inpatients undergoing orthopaedic surgery and in thromboprophylaxis following trauma. Outpatient treatment of acute proximal deep vein thrombosis with enoxaparin has also been shown to be cost effective compared with inpatient treatment using UFH. In general surgery, however, it remains to be determined whether enoxaparin is a cost-effective alternative to UFH. The cost effectiveness of enoxaparin compared with UFH in the treatment of unstable angina and non-Q-wave myocardial infarction has also been investigated in several countries using clinical outcomes data from the Efficacy and Safety of Subcutaneous Enoxaparin in Non-Q-wave Coronary Events (ESSENCE) randomised trial. ESSENCE demonstrated that enoxaparin was superior to UFH in terms of tolerability and efficacy, and cost saving at both 30-day and 1-year follow-ups. An increasing number of studies indicate enoxaparin to be of economic benefit when used for prevention and treatment of venous thromboembolism and treatment of acute coronary symdromes.