Low dose heparin versus low molecular weight heparin (Kabi 2165, Fragmin) in the prophylaxis of thromboembolic complications of abdominal oncological surgery

Comparison of efficacy and safety of thrombus prevention strategies after abdominal and pelvic cancer surgery: Bayesian network based meta-analysis

Background

The occurrence of venous thromboembolism (VTE) after abdominal and pelvic cancer surgery increases the risk of mortality and disability. However, there is insufficient evidence supporting the choice of anticoagulation strategies.

Methods

We searched PubMed, The Cochrane Library, Embase, and Web of Science for randomized controlled trials from inception to January 2024. Studies concerning thrombosis prevention after abdominal and pelvic surgery were included. Network meta-analysis(NMA) and direct meta-analysis (DMA) methods were employed to evaluate the efficacy and safety of various prophylactic strategies.

Results

Twenty clinical trials involving a total of 4923 patients were included. The DMA results showed that low molecular weight heparin (LMWH) was more effective in preventing VTE compared to no treatment (OR = 1.96; 95% CI: 1.21 to 3.19), and LMWH plus physiotherapy was more effective than LMWH (OR = 10.95; 95% CI: 1.33 to 90.40). The NMA results indicated that DOACs (OR = 0.34; 95% CI: 0.11 to 0.76) and LMWH (OR = 0.51; 95% CI: 0.32 to 0.77) were significantly effective in preventing venous thrombosis compared with no treatment. The cumulative ranking probability curve (SUCRA) showed that direct oral anticoagulants (DOACs) were the best intervention. In terms of major bleeding, unfractionated heparin (UFH) had a higher risk than LMWH, physiotherapy, and no treatment, with statistically significant differences. The SUCRA analysis indicated that physiotherapy was the best intervention for major bleeding.

Conclusion

Existing evidence suggests that DOACs can provide better thromboprophylaxis efficacy for patients after abdominal and pelvic cancer surgery, achieving an optimal balance between efficacy and safety. LMWH has become an intervention with efficacy second only to DOACs, with similar safety.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/ , identifier CRD42024513090.

Joint 2022 European Society of Thoracic Surgeons and The American Association for Thoracic Surgery guidelines for the prevention of cancer-associated venous thromboembolism in thoracic surgery

BACKGROUND

Venous thromboembolism (VTE), which includes deep vein thrombosis and pulmonary embolism, is a potentially fatal but preventable postoperative complication. Thoracic oncology patients undergoing surgical resection, often after multimodality induction therapy, represent among the highest risk groups for postoperative VTE. Currently there are no VTE prophylaxis guidelines specific to these thoracic surgery patients. Evidenced-based recommendations will help clinicians manage and mitigate risk of VTE in the postoperative period and inform best practice.

OBJECTIVE

These joint evidence-based guidelines from The American Association for Thoracic Surgery and the European Society of Thoracic Surgeons aim to inform clinicians and patients in decisions about prophylaxis to prevent VTE in patients undergoing surgical resection for lung or esophageal cancer.

METHODS

The American Association for Thoracic Surgery and the European Society of Thoracic Surgeons formed a multidisciplinary guideline panel that included broad membership to minimize potential bias when formulating recommendations. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used, including GRADE Evidence-to-Decision frameworks, which were subject to public comment.

RESULTS

The panel agreed on 24 recommendations focused on pharmacological and mechanical methods for prophylaxis in patients undergoing lobectomy and segmentectomy, pneumonectomy, and esophagectomy, as well as extended resections for lung cancer.

CONCLUSIONS

The certainty of the supporting evidence for the majority of recommendations was judged as low or very low, largely due to a lack of direct evidence for thoracic surgery. The panel made conditional recommendations for use of parenteral anticoagulation for VTE prevention, in combination with mechanical methods, over no prophylaxis for cancer patients undergoing anatomic lung resection or esophagectomy. Other key recommendations include: conditional recommendations for using parenteral anticoagulants over direct oral anticoagulants, with use of direct oral anticoagulants suggested only in the context of clinical trials; conditional recommendation for using extended prophylaxis for 28 to 35 days over in-hospital prophylaxis only for patients at moderate or high risk of thrombosis; and conditional recommendations for VTE screening in patients undergoing pneumonectomy and esophagectomy. Future research priorities include the role of preoperative thromboprophylaxis and the role of risk stratification to guide use of extended prophylaxis.

Joint 2022 European Society of Thoracic Surgeons and The American Association for Thoracic Surgery guidelines for the prevention of cancer-associated venous thromboembolism in thoracic surgery

BACKGROUND

Venous thromboembolism (VTE), which includes deep vein thrombosis and pulmonary embolism, is a potentially fatal but preventable postoperative complication. Thoracic oncology patients undergoing surgical resection, often after multimodality induction therapy, represent among the highest risk groups for postoperative VTE. Currently there are no VTE prophylaxis guidelines specific to these thoracic surgery patients. Evidenced-based recommendations will help clinicians manage and mitigate risk of VTE in the postoperative period and inform best practice.

OBJECTIVE

These joint evidence-based guidelines from The American Association for Thoracic Surgery and the European Society of Thoracic Surgeons aim to inform clinicians and patients in decisions about prophylaxis to prevent VTE in patients undergoing surgical resection for lung or esophageal cancer.

METHODS

The American Association for Thoracic Surgery and the European Society of Thoracic Surgeons formed a multidisciplinary guideline panel that included broad membership to minimize potential bias when formulating recommendations. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used, including GRADE Evidence-to-Decision frameworks, which were subject to public comment.

RESULTS

The panel agreed on 24 recommendations focused on pharmacological and mechanical methods for prophylaxis in patients undergoing lobectomy and segmentectomy, pneumonectomy, and esophagectomy, as well as extended resections for lung cancer.

CONCLUSIONS

The certainty of the supporting evidence for the majority of recommendations was judged as low or very low, largely due to a lack of direct evidence for thoracic surgery. The panel made conditional recommendations for use of parenteral anticoagulation for VTE prevention, in combination with mechanical methods, over no prophylaxis for cancer patients undergoing anatomic lung resection or esophagectomy. Other key recommendations include: conditional recommendations for using parenteral anticoagulants over direct oral anticoagulants, with use of direct oral anticoagulants suggested only in the context of clinical trials; conditional recommendation for using extended prophylaxis for 28 to 35 days over in-hospital prophylaxis only for patients at moderate or high risk of thrombosis; and conditional recommendations for VTE screening in patients undergoing pneumonectomy and esophagectomy. Future research priorities include the role of preoperative thromboprophylaxis and the role of risk stratification to guide use of extended prophylaxis. (J Thorac Cardiovasc Surg 2022;▪:1-31).

Guideline No. 417: Prevention of Venous Thromboembolic Disease in Gynaecological Surgery

OBJECTIVE

The primary objective of this clinical practice guideline is to provide gynaecologists with an algorithm and evidence to guide the use of thromboprophylaxis in gynaecological surgery.

TARGET POPULATION

All patients undergoing gynaecological surgery for benign or malignant indications.

BENEFITS, HARMS, AND COSTS

The implementation of this guideline will benefit patients undergoing gynaecological surgery and provide physicians with a standard algorithm for the use of perioperative thromboprophylaxis.

EVIDENCE

The following search terms were entered into MEDLINE, Google Scholar, and Cochrane in 2017 and 2018: VTE, PE, DVT, thromboprophylaxis, gynaecological surgery, heparin, graduated compression stocking, intermittent pneumatic stocking, obesity, pediatrics, minimally invasive surgery, heparin induced thrombocytopenia, regional anesthesia). Articles included were randomized controlled trials, meta-analyses, systematic reviews, and observational studies. Additional publications were identified from the reference lists of these articles. There were no date limits, but search results were limited to English language articles only. Searches were updated and incorporated into the guideline up to September 2018.

VALIDATION METHODS

The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and weak recommendations).

INTENDED USERS

Gynaecologists and other members of the surgical team. RECOMMENDATIONS (GRADE RATINGS IN PARENTHESES).

Risk of Postoperative Venous Thromboembolism After Surgery for Colorectal Malignancy: A Systematic Review and Meta-analysis

BACKGROUND

Colorectal cancer has the second highest mortality of any malignancy, and venous thromboembolism is a major postoperative complication.

OBJECTIVE

This study aimed to determine the variation in incidence of venous thromboembolism after colorectal cancer resection.

DATA SOURCES

Following PRISMA and MOOSE guidelines (PROSPERO, ID: CRD42019148828), Medline and Embase databases were searched from database inception to August 2019 including 3 other registered medical databases.

STUDY SELECTION

Two blinded reviewers screened studies with a third reviewer adjudicating any discordance. Eligibility criteria: Patients post colorectal cancer resection aged ≥18 years. Exclusion criteria: Patients undergoing completely endoscopic surgery and those without cancer resection. Selected studies were randomized controlled trials and population-based database/registry cohorts.

MAIN OUTCOME MEASURES

Thirty- and 90-day incidence rates of venous thromboembolism per 1000 person-years following colorectal cancer surgery.

RESULTS

Of 6441 studies retrieved, 28 met inclusion criteria. Eighteen were available for meta-analysis reporting on 539,390 patients. Pooled 30- and 90-day incidence rates of venous thromboembolism following resection were 195 (95% CI, 148-256, I2 99.1%) and 91 (95% CI, 56-146, I2 99.2%) per 1000 person-years. When separated by United Nations Geoscheme Areas, differences in the incidence of postoperative venous thromboembolism were observed with 30- and 90-day pooled rates per 1000 person-years of 284 (95% CI, 238-339) and 121 (95% CI, 82-179) in the Americas and 71 (95% CI, 60-84) and 57 (95% CI, 47-69) in Europe.

LIMITATIONS

A high degree of heterogeneity was observed within meta-analyses attributable to large cohorts minimizing within-study variance.

CONCLUSION

The incidence of venous thromboembolism following colorectal cancer resection is high and remains so more than 1 month after surgery. There is clear disparity between the incidence of venous thromboembolism after colorectal cancer surgery by global region. More robust population studies are required to further investigate these geographical differences to determine valid regional incidence rates of venous thromboembolism following colorectal cancer resection.

American Society of Hematology 2021 guidelines for management of venous thromboembolism: prevention and treatment in patients with cancer

BACKGROUND

Venous thromboembolism (VTE) is a common complication among patients with cancer. Patients with cancer and VTE are at a markedly increased risk for morbidity and mortality.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in their decisions about the prevention and treatment of VTE in patients with cancer.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The guideline development process was supported by updated or new systematic evidence reviews. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to assess evidence and make recommendations.

RESULTS

Recommendations address mechanical and pharmacological prophylaxis in hospitalized medical patients with cancer, those undergoing a surgical procedure, and ambulatory patients receiving cancer chemotherapy. The recommendations also address the use of anticoagulation for the initial, short-term, and long-term treatment of VTE in patients with cancer.

CONCLUSIONS

Strong recommendations include not using thromboprophylaxis in ambulatory patients receiving cancer chemotherapy at low risk of VTE and to use low-molecular-weight heparin (LMWH) for initial treatment of VTE in patients with cancer. Conditional recommendations include using thromboprophylaxis in hospitalized medical patients with cancer, LMWH or fondaparinux for surgical patients with cancer, LMWH or direct oral anticoagulants (DOAC) in ambulatory patients with cancer receiving systemic therapy at high risk of VTE and LMWH or DOAC for initial treatment of VTE, DOAC for the short-term treatment of VTE, and LMWH or DOAC for the long-term treatment of VTE in patients with cancer.

Prevention of venous thromboembolism in gynecological cancer patients undergoing major abdominopelvic surgery: A systematic review and network meta-analysis

OBJECTIVE

Although thromboprophylaxis is recommended to reduce death and disability from venous thromboembolism (VTE), it remains underused due to a perceived risk of bleeding, especially in major abdominopelvic surgical patients.

METHODS

We conducted a systematic literature review to identify all eligible randomized controlled trials (RCTs), searching MEDLINE and Scopus databases through November 25, 2020. RCTs published in any language were eligible if they studied in gynecological cancer patients undergoing major abdominopelvic surgery and assessed efficacy of mechanical and pharmacological interventions. Studies with insufficient data for pooling or those comparing different doses/schedules of interventions were excluded. Outcomes of interest were composite VTE (ie, deep vein thrombosis or pulmonary embolism) and major bleeding. Relevant data were extracted for direct and network meta-analyses. Risk ratios (RR) and 95% confidence interval (CI) were estimated and the best intervention probability calculated for each outcome. This study was registered with PROSPERO (CRD42019145508).

RESULTS

We identified 1990 studies; 20 RCTs (4970 patients) were eligible. The overall risk of bias was of some concern. In direct meta-analyses, antithrombins were superior to unfractionated heparin in preventing composite VTE (RR 0.69; 95% CI 0.48-0.99), with no difference detected in the rate of major bleeding for any pairwise comparison. In network meta-analyses, graduated compression stockings plus low-molecular-weight heparin (LMWH) was top-ranked for prevention of composite VTE, whereas sequential compression devices (SCD) ranked second, after no treatment, for major bleeding. In a clustered ranking plot, SCD plus LMWH provided optimal balance between efficacy and safety.

CONCLUSIONS

SCD plus LMWH might be safe and effective in VTE prevention following gynecological cancer surgery. However, the patient's bleeding risk should be considered to balance the risk and benefit of treatment.

American Society of Hematology 2019 guidelines for management of venous thromboembolism: prevention of venous thromboembolism in surgical hospitalized patients

BACKGROUND

Venous thromboembolism (VTE) is a common source of perioperative morbidity and mortality.

OBJECTIVE

These evidence-based guidelines from the American Society of Hematology (ASH) intend to support decision making about preventing VTE in patients undergoing surgery.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline-development process, including performing systematic reviews. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 30 recommendations, including for major surgery in general (n = 8), orthopedic surgery (n = 7), major general surgery (n = 3), major neurosurgical procedures (n = 2), urological surgery (n = 4), cardiac surgery and major vascular surgery (n = 2), major trauma (n = 2), and major gynecological surgery (n = 2).

CONCLUSIONS

For patients undergoing major surgery in general, the panel made conditional recommendations for mechanical prophylaxis over no prophylaxis, for pneumatic compression prophylaxis over graduated compression stockings, and against inferior vena cava filters. In patients undergoing total hip or total knee arthroplasty, conditional recommendations included using either aspirin or anticoagulants, as well as for a direct oral anticoagulant over low-molecular-weight heparin (LMWH). For major general surgery, the panel suggested pharmacological prophylaxis over no prophylaxis, using LMWH or unfractionated heparin. For major neurosurgery, transurethral resection of the prostate, or radical prostatectomy, the panel suggested against pharmacological prophylaxis. For major trauma surgery or major gynecological surgery, the panel suggested pharmacological prophylaxis over no prophylaxis.

Incidence, risk factors, and outcomes of venous thromboembolism after oncologic surgery: A systematic review and meta-analysis

BACKGROUND

The risk and prognosis of VTE associated with oncologic surgery need to be quantified to guide patient management. We aimed to examine the availability of data and to report the incidence of venous thromboembolism (VTE) in cancer patients after surgery, as well as the clinical outcomes of VTE following oncologic surgery.

METHODS

We searched multiple databases for terms related to VTE after oncologic surgery from inception to November 1, 2017. A random-effects meta-analysis was done to calculate the pooled incidence of VTE.

RESULTS

Of the 8611 citations identified, 136 studies including 1,481,659 patients met the eligibility criteria. The overall incidence of VTE was estimated to be 2.3% (95% CI 2.1-2.5). Bone and soft tissue cancer (10.6%, 95% CI 2.9-18.2) and lung cancer (8.1%, 95% CI 3.7-12.6) were associated with the highest and second highest risk of postoperative VTE, respectively. Age (standardized mean difference [SMD] = 0.46, 95% CI 0.40-0.53; I² = 93.8%), radiation (OR 1.29, 95% CI 1.03-1.62; I² = 34.6%), transfusion (OR 1.96, 95% CI 1.48-2.59; I² = 57.0%), and operative time (SMD = 1.12, 95% CI 1.07-1.16; I² = 100%) were possible risk factors for postoperative VTE. Patients with VTE versus those without had increased odds of all-cause fatal events (11.15, 95% CI 4.07-30.56; I² = 92.0%).

CONCLUSIONS

The risk of VTE after oncologic surgery remains high, and this risk varied according to the cancer type, study region, surgical location, and thromboprophylactic strategy. VTE is associated with increased mortality at the early stage of cancer surgery.

Anticoagulation for perioperative thromboprophylaxis in people with cancer

BACKGROUND

The choice of the appropriate perioperative thromboprophylaxis for people with cancer depends on the relative benefits and harms of different anticoagulants.

OBJECTIVES

To systematically review the evidence for the relative efficacy and safety of anticoagulants for perioperative thromboprophylaxis in people with cancer.

SEARCH METHODS

This update of the systematic review was based on the findings of a comprehensive literature search conducted on 14 June 2018 that included a major electronic search of Cochrane Central Register of Controlled Trials (CENTRAL, 2018, Issue 6), MEDLINE (Ovid), and Embase (Ovid); handsearching of conference proceedings; checking of references of included studies; searching for ongoing studies; and using the 'related citation' feature in PubMed.

SELECTION CRITERIA

Randomized controlled trials (RCTs) that enrolled people with cancer undergoing a surgical intervention and assessed the effects of low-molecular weight heparin (LMWH) to unfractionated heparin (UFH) or to fondaparinux on mortality, deep venous thrombosis (DVT), pulmonary embolism (PE), bleeding outcomes, and thrombocytopenia.

DATA COLLECTION AND ANALYSIS

Using a standardized form, we extracted data in duplicate on study design, participants, interventions outcomes of interest, and risk of bias. Outcomes of interest included all-cause mortality, PE, symptomatic venous thromboembolism (VTE), asymptomatic DVT, major bleeding, minor bleeding, postphlebitic syndrome, health related quality of life, and thrombocytopenia. We assessed the certainty of evidence for each outcome using the GRADE approach (GRADE Handbook).

MAIN RESULTS

Of 7670 identified unique citations, we included 20 RCTs with 9771 randomized people with cancer receiving preoperative prophylactic anticoagulation. We identified seven reports for seven new RCTs for this update.The meta-analyses did not conclusively rule out either a beneficial or harmful effect of LMWH compared with UFH for the following outcomes: mortality (risk ratio (RR) 0.82, 95% confidence interval (CI) 0.63 to 1.07; risk difference (RD) 9 fewer per 1000, 95% CI 19 fewer to 4 more; moderate-certainty evidence), PE (RR 0.49, 95% CI 0.17 to 1.47; RD 3 fewer per 1000, 95% CI 5 fewer to 3 more; moderate-certainty evidence), symptomatic DVT (RR 0.67, 95% CI 0.27 to 1.69; RD 3 fewer per 1000, 95% CI 7 fewer to 7 more; moderate-certainty evidence), asymptomatic DVT (RR 0.86, 95% CI 0.71 to 1.05; RD 11 fewer per 1000, 95% CI 23 fewer to 4 more; low-certainty evidence), major bleeding (RR 1.01, 95% CI 0.69 to 1.48; RD 0 fewer per 1000, 95% CI 10 fewer to 15 more; moderate-certainty evidence), minor bleeding (RR 1.01, 95% CI 0.76 to 1.33; RD 1 more per 1000, 95% CI 34 fewer to 47 more; moderate-certainty evidence), reoperation for bleeding (RR 0.93, 95% CI 0.57 to 1.50; RD 4 fewer per 1000, 95% CI 22 fewer to 26 more; moderate-certainty evidence), intraoperative transfusion (mean difference (MD) -35.36 mL, 95% CI -253.19 to 182.47; low-certainty evidence), postoperative transfusion (MD 190.03 mL, 95% CI -23.65 to 403.72; low-certainty evidence), and thrombocytopenia (RR 3.07, 95% CI 0.32 to 29.33; RD 6 more per 1000, 95% CI 2 fewer to 82 more; moderate-certainty evidence). LMWH was associated with lower incidence of wound hematoma (RR 0.70, 95% CI 0.54 to 0.92; RD 26 fewer per 1000, 95% CI 39 fewer to 7 fewer; moderate-certainty evidence). The meta-analyses found the following additional results: outcomes intraoperative blood loss (MD -6.75 mL, 95% CI -85.49 to 71.99; moderate-certainty evidence); and postoperative drain volume (MD 30.18 mL, 95% CI -36.26 to 96.62; moderate-certainty evidence).In addition, the meta-analyses did not conclusively rule out either a beneficial or harmful effect of LMWH compared with Fondaparinux for the following outcomes: any VTE (DVT or PE, or both; RR 2.51, 95% CI 0.89 to 7.03; RD 57 more per 1000, 95% CI 4 fewer to 228 more; low-certainty evidence), major bleeding (RR 0.74, 95% CI 0.45 to 1.23; RD 8 fewer per 1000, 95% CI 16 fewer to 7 more; low-certainty evidence), minor bleeding (RR 0.83, 95% CI 0.34 to 2.05; RD 8fewer per 1000, 95% CI 33 fewer to 52 more; low-certainty evidence), thrombocytopenia (RR 0.35, 95% CI 0.04 to 3.30; RD 14 fewer per 1000, 95% CI 20 fewer to 48 more; low-certainty evidence), any PE (RR 3.13, 95% CI 0.13 to 74.64; RD 2 more per 1000, 95% CI 1 fewer to 78 more; low-certainty evidence) and postoperative drain volume (MD -20.00 mL, 95% CI -114.34 to 74.34; low-certainty evidence) AUTHORS' CONCLUSIONS: We found no difference between perioperative thromboprophylaxis with LMWH versus UFH and LMWH compared with fondaparinux in their effects on mortality, thromboembolic outcomes, major bleeding, or minor bleeding in people with cancer. There was a lower incidence of wound hematoma with LMWH compared to UFH.

Comparison of Unfractionated Versus Low Molecular Weight Heparin for Deep Vein Thrombosis Prophylaxis During Breast and Pelvic Cancer Surgery: Efficacy, Safety, and Follow-up

In a prospective, double-blind randomized trial the efficacy and safety of low molecular weight heparin and un fractionated heparin were compared for the prevention of post operative deep vein thrombosis in patients undergoing major surgery for breast and pelvic cancer. Three hundred fifty-eight patients were randomly allocated to the two treatment groups. Thirty-four of these were excluded from the study. Of the re maining 324 patients, 164 received 5000 IU unfractionated heparin three times daily and 160 received 3000 anti-Xa units of low molecular weight heparin once daily. Treatment was started 2 to 5 hours preoperatively and continued for 7 days. The occurrence of deep vein thrombosis was determined by impedence plethysmography and/or venography. Deep vein thrombosis was diagnosed in 10 (6.3%) of 160 patients taking low molecular weight heparin and 10 (6.1 %) of 164 patients treated with unfractionated heparin (relative risk: 1.03; 95% confidence interval 0.44-2.39; p = 1.0). Major bleeding events occurred in 27 (16.8%) patients in the low molecular weight heparin group and 47 (28.7%) in the unfractionated heparin group (relative risk: 0.59; 95% confidence interval: 0.39-0.89; p = .01). Severe intraoperative bleeding was observed in three patients in the unfractionated heparin group and in none of the patients in the low molecular weight heparin group. Excessive intraoperative bleeding was less frequent in the low molecular weight heparin group (9.4% vs. 14%, p = .23) as was wound hematoma (11.3 vs. 17.7%, p = .12). Bleeding episodes with low molecular weight heparin were less likely to lead to further surgery for evacuation of hematoma (0.6% vs. 2.5%, p = .37). Perioperative death rate was 3.1 % in the low molecular weight heparin group and 1.8% in unfractionated heparin group (rela tive risk: 1.72, 95% confidence interval: 0.42-7.07; p = .49). Follow-up data were available for 316 patients for an average of 20 months after surgery. There were 35 further cancer deaths (11 low molecular weight heparin group, 24 unfractionated heparin group) and 23 patients with late onset thromboembolic complications (11 low molecular weight heparin group, 12 un fractionated heparin group). The two drugs were of similar efficacy but the frequency of major bleeding was 41.1% less in the low molecular weight heparin group.

Optimal Duration for Prophylaxis of Deep Vein Thrombosis: The New Focus?

It is usual to stop prophylaxis of most surgical patients at hospital discharge. However, there is increas ing evidence that some patients are at risk of thromboem bolism after treatment is stopped. Some evidence and several proposals from the literature are presented, but to date, the situation remains unclear.

Bemiparin for thromboprophylaxis after benign gynecologic surgery: a randomized clinical trial

BACKGROUND

Venous thromboembolism (VTE) is the leading cause of mortality and morbidity in women following gynecologic surgery.

OBJECTIVES

To determine the efficacy of a second-generation low molecular weight heparin (bemiparin) for thromboprophylaxis after benign gynecologic surgery.

METHODS

We performed a single-blind randomized controlled trial including women in the moderate-risk, high-risk and highest-risk groups for developing VTE after benign gynecologic surgery. Participants were randomized at a 1 : 1 ratio into parallel groups to receive either seven daily doses of 3500 IU of subcutaneous bemiparin or to a non-intervention group receiving standard rehydration and advice on ambulation. Participants were followed up for 7 days and 30 days postoperatively for symptomatic VTE, which was confirmed by compression Doppler ultrasound, magnetic resonance imaging, or computed tomographic pulmonary angiography, according to the type of VTE.

RESULTS

In total, 387 participants were randomized to the bemiparin group and 387 to the non-intervention group. The incidence of symptomatic VTE (deep vein thrombosis and pulmonary embolism) events was lower (0/377) in participants who received bemiparin than in those who received no pharmacologic intervention (12/380, 3.2%; 95% confidence interval [CI] 0.002-0.6). Logistic regression analysis showed significant associations between VTE and immobility (odds ratio [OR] 7.1; 95% CI 1.3-36.2), varicose veins (OR 16.8; 95% CI 3.1-76.2), and thrombophilia (OR 39.3; 95% CI 1.5-1006.7). There were no major bleeding events or side effects related to the use of bemiparin.

CONCLUSIONS

Bemiparin was an effective thromboprophylactic agent for preventing venous thrombosis after benign gynecologic surgery.

Low molecular weight heparin versus unfractionated heparin for perioperative thromboprophylaxis in patients with cancer

BACKGROUND

The choice of the appropriate perioperative thromboprophylaxis in patients with cancer depends on the relative benefits and harms of low molecular weight heparin (LMWH) and unfractionated heparin (UFH).

OBJECTIVES

To update a systematic review of the evidence for the relative efficacy and safety of LMWH and UFH for perioperative thromboprophylaxis in patients with cancer.

SEARCH METHODS

We performed a comprehensive search for trials of anticoagulation in patients with cancer including a February 2013 electronic search of: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and EMBASE. We also handsearched conference proceedings, reviewed reference list of included studies, used the 'related citations' feature in PubMed, and searched clinicaltrials.gov for ongoing studies.

SELECTION CRITERIA

Randomized controlled trials (RCTs) that enrolled patients with cancer undergoing a surgical intervention and compared the effects of LMWH to UFH on mortality, deep venous thrombosis (DVT), pulmonary embolism (PE), bleeding outcomes, or thrombocytopenia.

DATA COLLECTION AND ANALYSIS

Two review authors independently used a standardized form to extract in duplicate data on participants, interventions, outcomes of interest, and risk of bias. Where possible, we conducted meta-analyses using the random-effects model.

MAIN RESULTS

Of 9559 identified unique citations, we included 16 RCTs with 12,890 patients with cancer, all using preoperative prophylactic anticoagulation. We identified no new study with this update. The overall quality of evidence was moderate. The meta-analyses did not conclusively rule out either a beneficial or harmful effect of LMWH compared with UFH for the following outcomes: mortality (risk ratio (RR) 0.89; 95% confidence interval (CI) 0.74 to 1.08), PE (RR 0.73; 95% CI 0.34 to 1.54), symptomatic DVT (RR 0.50; 95% CI 0.20 to 1.28), asymptomatic DVT (RR 0.81; 95% CI 0.66 to 1.01),major bleeding (RR 0.85; 95% CI 0.52 to 1.37), and minor bleeding (RR 0.92; 95% CI 0.47 to 1.79). LMWH was associated with lower incidence of wound hematoma (RR 0.68; 95% CI 0.52 to 0.88) but higher volume of intraoperative transfusion (mean difference (MD) 74 mL; 95% CI 47 to 102). The meta-analyses found no statistically significant differences for any of the following outcomes: reoperation for bleeding (RR 0.72; 95% CI 0.06 to 8.48) , intraoperative blood loss (MD= -6mL; 95% CI -87 to 74), postoperative transfusion (MD= 79mL; 95% CI -54 to 211), postoperative drain volume (MD= 27mL; 95% CI -44 to 98), and thrombocytopenia (RR 1.33; 95% CI 0.59 to 3.00).

AUTHORS' CONCLUSIONS

We found no difference between perioperative thromboprophylaxis with LMWH versus UFH in their effects on mortality, thromboembolic outcomes, major bleeding, or minor bleeding in patients with cancer. Further trials are needed to evaluate the benefits and harms of different heparin thromboprophylaxis strategies in this population more thoroughly.

Thromboembolism prevention in surgery of digestive cancer

BACKGROUND

The venous thromboembolism is a common complication after surgical treatment in general and, in particular, on the therapeutic management on cancer. Surgery of the digestive tract has been reported to induce this complication. Patients with digestive cancer have substantial increased risk of initial or recurrent thromboembolism.

AIM

To provide to surgeons working in digestive surgery and general surgery guidance on how to make safe thromboprophylaxis for patients requiring operations in the treatment of their gastrointestinal malignancies.

METHODS

The guideline was based on 15 relevant clinical issues and related to the risk factors, treatment and prognosis of the patient undergoing surgical treatment of cancer on digestive tract. They focused thromboembolic events associated with operations and thromboprophylaxis. The questions were structured using the PICO (Patient, Intervention or Indicator, Comparison and Outcome), allowing strategies to generate evidence on the main primary bases of scientific information (Medline / Pubmed, Embase, Lilacs / Scielo, Cochrane Library, PreMedline via OVID). Evidence manual search was also conducted (BDTD and IBICT). The evidence was recovered from the selected critical evaluation using discriminatory instruments (scores) according to the category of the question: risk, prognosis and therapy (JADAD Randomized Clinical Trials and New Castle Ottawa Scale for studies not randomized). After defining potential studies to support the recommendations, they were selected by the strength of evidence and grade of recommendation according to the classification of Oxford, including the available evidence of greater strength.

RESULTS

A total of 53,555 papers by title and / or abstract related to issue were found. Of this total were selected (1st selection) 478 studies that were evaluated as full-text. From them to support the recommendations were included in the consensus 132 papers. The 15 questions could be answered with evidence grade of articles with 31 A, 130 B, 1 C and 0 D.

CONCLUSION

It was possible to prepare safe recommendations as guidance for thromboembolism prophylaxis in operations on the digestive tract malignancies, addressing the most frequent topics of everyday work of digestive and general surgeons.

Venous Thromboembolism in Cancer Patients Undergoing Major Abdominal Surgery: Prevention and Management

Cancer is an important risk factor for venous thrombosis. Venous thromboembolism is one of the most common complications of cancer and the second leading cause of death in these patients. Recent research has given insight into mechanism and various risk factors in cancer patients which predispose to thromboembolism. The purpose of this review is to summarize the current knowledge on the prophylaxis, diagnosis, and management of venous thromboembolism in these patients.

Macroscopic hematuria-a leading urological problem in patients on anticoagulant therapy: is the common diagnostic standard still advisable?

All urological standards of care are based on the past definition of the clinical importance of macroscopic hematuria. The aim of the study was to assess the phenomenon of iatrogenic hematuria in current clinical practice and analyze its origins in patients receiving anticoagulant drugs. Retrospective analysis of clinical documentation of 238 patients that were consulted for hematuria in 2007–2009 by 5 consultant urologists was performed. In the group of 238 patients with hematuria, 155 (65%) received anticoagulants. Abnormalities of urinary tract were found in 45 (19%) patients. Estimated cost of a single neoplasm detection reached the value of 3252 Euro (mean 3-day hospitalization). The strong correlation between the presence of hematuria and anticoagulant treatment was observed. Authors suggest to redefine the present and future role of hematuria from a standard manifestation of serious urological disease to a common result of a long-term anticoagulant therapy.

Meta-regression analysis to indirectly compare prophylaxis with dalteparin or enoxaparin in patients at high risk for venous thromboembolic events

BACKGROUND

Dalteparin and enoxaparin are recommended as thromboprophylaxis for at least 10 days in patients undergoing abdominal surgery (AS) or hospitalized patients with acute medical illnesses. Even though both agents have proven clinical effectiveness through randomized trials, there have been no head-to-head studies. In this evaluation, indirect statistical techniques were used to compare safety and efficacy between dalteparin and enoxaparin in these 2 high-risk patient populations.

METHODS

A literature search was conducted from January 1980 to November 2010 for randomized trials evaluating dalteparin or enoxaparin prophylaxis following AS or in hospitalized patients. Binary outcomes for safety and efficacy were statistically pooled using fixed or random effects models in cases of significant heterogeneity. In trials where a common control was used (eg, unfractionated heparin [UH]), indirect statistical comparisons between dalteparin and enoxaparin were performed using meta-regression analysis with active drug as the primary independent variable.

RESULTS

The meta-analysis in AS patients showed that enoxaparin or dalteparin had comparable efficacy to UH in terms of venous thromboembolic events (VTEs; relative risk reduction [RR] = 0.87, P = .46). The indirect statistical comparison was unable to find significant differences between enoxaparin and dalteparin in terms of risk for VTE (P = .84), major bleeding (P = .38), heparin-induced thrombocytopenia ([HIT]; P = .084), or death (P = .97). In acutely ill medical patients, treatment with enoxaparin or dalteparin had a 52% VTE risk reduction compared to placebo (RR = 0.48, P < .001). The indirect comparison was also unable to find significant differences between enoxaparin and dalteparin in terms of VTEs (P = .15), major bleeds (P = .39), HIT (P = .48), and death (P = .41).

CONCLUSIONS

The findings suggest comparable safety and efficacy between dalteparin and enoxaparin in AS and in acutely ill medical patients.

Low molecular weight heparin versus unfractionated heparin for perioperative thromboprophylaxis in patients with cancer

BACKGROUND

The choice of the appropriate perioperative thromboprophylaxis in patients with cancer depends on the relative benefits and harms of low molecular weight heparin (LMWH) and unfractionated heparin (UFH).

OBJECTIVES

To systematically review the evidence for the relative efficacy and safety of LMWH and UFH for perioperative thromboprophylaxis in patients with cancer.

SEARCH METHODS

A comprehensive search for trials of anticoagulation in cancer patients including a February 2010 electronic search of: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and ISI Web of Science.

SELECTION CRITERIA

Randomized controlled trials (RCTs) that enrolled cancer patients undergoing a surgical intervention and compared the effects of LMWH to UFH on mortality, deep venous thrombosis (DVT), pulmonary embolism (PE), bleeding outcomes, and thrombocytopenia.

DATA COLLECTION AND ANALYSIS

Two review authors used a standardized form to independently extract in duplicate data on risk of bias, participants, interventions and outcomes of interest. Where possible, we conducted meta-analyses using the random-effects model.

MAIN RESULTS

Of 8187 identified citations, we included 16 RCTs with 11,847 patients in the meta-analyses, all using preoperative prophylactic anticoagulation. The overall quality of evidence was moderate. The meta-analysis did not conclusively rule out either a beneficial or harmful effect of LMWH compared to UFH for the following outcomes: mortality (RR = 0.90; 95% CI 0.73 to 1.10), symptomatic DVT (RR = 0.73; 95% CI 0.23 to 2.28), PE (RR = 0.59; 95% CI 0.25 to1.41), minor bleeding (RR = 0.88; 95% CI 0.47 to 1.66) and major bleeding (RR = 0.84; 95% CI 0.52 to 1.36). LMWH was associated with lower incidence of wound hematoma (RR = 0.60; 95% CI 0.43, 0.84) while UFH was associated with higher incidence of intra-operative transfusion (RR = 1.16; 95% CI 0.69,1.62).

AUTHORS' CONCLUSIONS

We found no difference between perioperative thromboprophylaxis with LMWH verus UFH in their effects on mortality and embolic outcomes in patients with cancer. Further trials are needed to more carefully evaluate the benefits and harms of different heparin thromboprophylaxis strategies in this population.

Cancer-associated thrombosis: prevention and treatment

Patients with cancer are at high risk to develop venous thromboembolism, and they are also more likely to develop complications from anticoagulant treatment. Because little research has focused on the oncology population to date, the optimal methods of prophylaxis and treatment remain uncertain in some clinical situations. Currently, low molecular weight heparin and warfarin are the most frequently used pharmacologic agents; however, they have their limitations. Other therapeutic options, such as inferior caval filters, are poorly studied and remain controversial. A summary of the most recent evidence on the prevention and treatment of venous thromboembolism in cancer patients is presented here.

Prophylactic and therapeutic anticoagulation for thrombosis: major issues in oncology

Venous thromboembolism (VTE) is a major cause of morbidity and mortality in patients with cancer. Primary prevention with pharmacologic agents (or mechanical methods, if anticoagulants are contraindicated) is recommended in all cancer patients hospitalized for surgical or medical reasons. The role of prophylaxis in outpatients is less certain because of the diversity of the patient populations and their cancer treatments with respect to the associated risks of VTE and bleeding. Treatment with low-molecular weight heparin is the recommended first-line approach in cancer patients with newly diagnosed VTE, and is usually continued for a minimum of 3-6 months. Other management issues that require further research include the optimum duration of anticoagulant therapy, the treatment of recurrent VTE, the role of vena cava filters, the effects of VTE and its treatment on quality of life, and the impact of anticoagulants on survival. Newer anticoagulants hold promise in providing more-effective and convenient treatment of VTE in this high-risk population, but further studies are awaited.

Management of venous thromboembolism in patients with cancer: role of dalteparin

Cancer is a major risk factor for the development of venous thromboembolism (VTE). Conventional anticoagulant therapy with a vitamin K antagonist is more problematic in cancer patients due to an increased risk of recurrent VTE, and an increased risk of anticoagulant-related bleeding. In recent years, there has been a shift toward treating cancer patients with VTE with extended duration dalteparin. Dalteparin, a low-molecular-weight heparin, has been shown to be more effective, and as safe as conventional anticoagulant therapy, in cancer patients with VTE. This paper will (a) review the relationship between cancer and VTE, and (b) provide an overview of the role of dalteparin in the management of VTE in patients with cancer.

WITHDRAWN: Anticoagulant and aspirin prophylaxis for preventing thromboembolism after major gynaecological surgery

BACKGROUND

The reported overall risk of deep venous thrombosis in gynaecological surgery ranges from 7 to 45%. Fatal pulmonary embolism is estimated to occur in nearly 1% of these women. Pharmaceutical interventions are one possible prophylactic measure for preventing emboli in women undergoing major gynaecological surgery. Agents include unfractionated heparin (low -dose and adjusted-dose), low-molecular-weight heparins, heparinoids and warfarin.

OBJECTIVES

The objective of this review was to evaluate the effectiveness of warfarin, heparin and aspirin in preventing thromboembolism after major gynaecological surgery.

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders and Subfertility Group trials register (searched 15 August 2003), the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library issue 2, 2003), MEDLINE (1966 to April 2003), EMBASE (1985 to April 2003), and CINAHL (1982 to April 2003). References from relevant articles were searched and authors contacted where necessary. In addition we contacted experts in the field for unpublished works.

SELECTION CRITERIA

Randomised controlled trials of heparins, warfarin or aspirin to prevent thromboembolism after major gynaecological surgery were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Thirty-three trials were identified in the initial search. On careful inspection only eight of these met the inclusion criteria. Trials were data extracted and assessed for quality by at least two reviewers. Data were combined for meta-analysis using odds ratios for dichotomous data or weighted mean difference for continuous data. A random effects statistical model was used.

MAIN RESULTS

The meta-analysis of heparin versus placebo found a statistically significant decrease in the number of DVTs in both the all women group (including those with and without malignancy) (OR 0.30, 95% CI 0.12 to 0.76) and the subgroup of only women with malignancy (OR 0.30, 95% CI 0.10 to 0.89). There was no significant difference in the incidence of PE. Oral warfarin reduced DVT when compared to placebo in all women (OR 0.22, 95% CI 0.06 to 0.86) and in women with malignancy (OR 0.18, 95% CI 0.04 to 0.87). Meta-analyses of UH and LMWH showed no statistical difference in any comparison. No studies compared aspirin alone to placebo, heparin or warfarin. There was a statistically significant increase in injection site haematomas associated with heparin compared to placebo (OR 0.30, 95% CI 0.10 to 0.89).

AUTHORS' CONCLUSIONS

Women, undergoing major gynaecological surgery and without contraindications to anticoagulants should be offered thromboprophylaxis. Evidence suggests that UH and LMWH are equally as effective in preventing DVT and the one trial available suggests that warfarin is as effective as UH. There is no evidence as yet to suggest that warfarin, heparin or aspirin reduce incidence of PE.

Venous thromboembolism prevention in gynecologic cancer surgery: A systematic review

OBJECTIVES

Advanced age, pelvic surgery, and the presence of malignancy place gynecologic oncology patients at high risk for venous thromboembolism (VTE). This study was designed to systematically analyze the world's literature on VTE in these patients and determine the optimal prophylaxis regimen.

METHODS

Computerized searches of Pubmed, Ovid, DARE, ACP Journal Club, Cochrane Database of Systematic Reviews, and Cochrane Controlled Trials Registry 1966-2005 were performed, as well as EMBASE 1980-2005. Major conferences and target references were hand-searched. Inclusion criteria were randomized controlled trials (RCTs) evaluating VTE prophylaxis with heparin, low-molecular-weight heparin (LMWH), and sequential compression devices (SCD). The search yielded 278 articles; 11 met inclusion criteria. Data were abstracted by one author and analyzed with the Mantel-Haenszel method.

RESULTS

The analysis of heparin-versus-control revealed a significant decrease in DVT in patients receiving heparin (RR=0.58, 95% CI 0.35-0.95). There were no significant differences in EBL or transfusions between the two groups. In the 320 patients in the heparin vs. LMWH studies, there was no significant difference in DVT (RR 0.91, 95% CI 0.38-2.17), although power analysis demonstrated insufficient numbers to show a difference. No patient in either group required re-exploration for bleeding.

CONCLUSIONS

All gynecologic cancer patients should receive VTE prophylaxis. Although heparin, LMWH, and SCD have been shown to be safe and effective, due to the paucity of data in the gynecologic oncology literature, no one prevention modality can be considered superior at this time. Adequately powered RCTs are urgently needed to determine the optimal regimen in these high-risk patients.

Risk of venous thromboembolism in patients undergoing cancer surgery and options for thromboprophylaxis

Patients with cancer have an increased risk of developing venous thromboembolism (VTE) due to a hypercoagulable state associated with malignancy. This risk is further complicated in patients undergoing cancer-related surgery due to immobility, other cancer treatments, and biologic changes associated with surgery. Despite this relatively high risk of VTE, many patients are not prescribed adequate prophylaxis in the pre- or post-operative periods. This article reviews available measures for thromboprophylaxis in light of current guidelines.

A systematic review of deep venous thrombosis prophylaxis in cancer patients: implications for improving quality

INTRODUCTION

Deep venous thrombosis (DVT) prophylaxis is particularly important for surgical oncologists given the high rate of DVT in patients with malignancy. Additionally, DVT prophylaxis may soon be implemented by some payers as a "pay for performance" quality measure. This is a systematic review of randomized controlled trial (RCT) evidence for DVT prophylaxis in cancer patients undergoing surgery. We examine overall rates of DVT, the efficacy of high versus low-dose heparin prophylaxis, and the rate of bleeding complications.

METHODS

The Medline database was searched for English language RCTs using key words DVT, venous thromboembolism, prophylaxis, and general surgery. Inclusion criteria were RCTs evaluating surgical oncology patients.

RESULTS

Fifty-five RCTs studied DVT prophylaxis in surgery (nonorthopedic) patients. Twenty-six RCTs evaluated 7,639 cancer patients. The overall DVT rate was 12.7% for pharmacologic prophylaxis and 35.2% for controls. High-dose low-molecular weight heparin (LMWH) was more effective than low dose, lowering the DVT rate from 14.5% to 7.9% (P < 0.01). Heparin decreased the rate of proximal DVTs. Bleeding complications requiring discontinuation of prophylaxis occurred in 3% of the patients. There was no difference between LMWH and unfractionated heparin in efficacy, DVT location, or bleeding complications.

CONCLUSION

Using RCT data, this study demonstrates a greatly reduced DVT rate with pharmacologic prophylaxis in cancer patients, and higher doses appear more effective. Complication rates are low and should not prevent the use of prophylaxis in most patients. Finally, we found no difference between LMWH and unfractionated heparin in these RCTs. These results highlight the importance of routine pharmacologic prophylaxis in surgical patients with malignancy.

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.

Maladie thromboembolique périopératoire et obstétricale. Pathologie gynécologique et obstétricale

Venous thromboembolism is a leading cause of maternal mortality in many countries, including France. Most enquiries have repeatedly demonstrated that many deaths could be avoided, suggesting the need to update and ensure a wider diffusion of recommendations. Although thromboembolism-induced maternal death plays a major role, the absolute incidence of events remains low, reducing the ability to perform well-designed research and the level of recommendations presented. Many personal or pregnancy-related factors have been identified as increasing the risk of thromboembolism in pregnant patients but few of them have been associated with a significantly increased risk. A history of thromboembolic event and some thrombophilic factors (including antithrombin deficiency and antiphospholipid syndrome) carry the greatest risk. Pregnancy itself, caesarean delivery and the postpartum period, although associated with an increased risk play a minor role when not combined with other risk factors. Prophylactic treatment relies mainly on low molecular weight heparins which safety is now well established in pregnant patients. Dose and duration of treatment should be adapted to the perceived level of risk. The occurrence of a thromboembolic event is also increased after gynaecological surgery but major and cancer surgery carry the greatest risk. Here also, low molecular weight heparins play a leading role, although non pharmacologic means are useful. Dose and duration should be dependent on the level of risk.

Low-Molecular-Weight Heparin (Dalteparin) in Women With Gynecologic Malignancy

OBJECTIVE

To compare the efficacy of dalteparin, a low-molecular-weight heparin, to unfractionated heparin (UFH) in the prevention of deep venous thrombosis (DVT) and pulmonary embolism in patients after surgery for gynecologic malignancy.

METHODS

The medical records of all patients undergoing major surgery on the Gynecologic Oncology Service at the Massachusetts General Hospital from July 2002 through April 2003 were reviewed. Patients with confirmed malignancy were included. Between July 1, 2002, and November 15, 2002, dalteparin (5,000 U subcutaneously each day) was used for postoperative prophylaxis for DVT and pulmonary embolus. After November 15, 2002, the method of prophylaxis was changed to UFH (5,000 U subcutaneously every 8 hours) exclusively. Patients were evaluated for DVT or pulmonary embolus based on clinical suspicion using computed tomographic angiography, ventilation and perfusion scan, or lower extremity doppler.

RESULTS

A total of 214 patients were identified who met study criteria. Dalteparin was administered to 103 patients, and UFH was administered to 111. The rates of clinically significant DVT or pulmonary embolus in patients receiving dalteparin and UFH were 8.9% and 1.2%, respectively (P = .009). Major risk factors for DVT or pulmonary embolus, including age, obesity, duration of surgery, and type of malignancy, did not differ between groups. There were no significant differences in bleeding complications or transfusion requirements between groups.

CONCLUSION

The low-molecular-weight heparin dalteparin dosed 5,000 U daily is inadequate postoperative prophylaxis in women undergoing surgery for gynecologic cancer. In addition, heparin administered every 8 hours was not associated with increased bleeding complications. The use of dalteparin at the doses used in this study should be questioned until a large randomized trial shows efficacy in these high-risk patients.

Management of thrombosis in cancer: primary prevention and secondary prophylaxis

Although traditional anticoagulant regimens are highly effective and safe in most patients with venous thromboembolism (VTE), the aggressive natural history of VTE and the high risk of serious bleeding in cancer patients can complicate the management of VTE. In addition, because few clinical trials have focused on the prevention and treatment of VTE in this unique patient population, many clinical questions regarding the care of cancer patients with VTE remain unanswered. Currently, low-molecular-weight heparins and oral vitamin K antagonists are the most commonly used agents for the primary and secondary prophylaxis of VTE in patients with or without cancer, but their use is associated with pharmacological and practical limitations. This review will provide an up-to-date summary of the clinical trials that have addressed the management of VTE in patients with cancer. A brief discussion of the potential application of novel anticoagulants in these clinical settings is also included.

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.

Primary and secondary prophylaxis of venous thromboembolism with low-molecular-weight heparins: prolonged thromboprophylaxis, an alternative to vitamin K antagonists

Low-molecular-weight heparins (LMWHs) are used widely in the treatment and prevention of venous thromboembolism (VTE). The LMWHs dalteparin and enoxaparin reduce the rate of VTE by at least 50% if administered for 4-5 weeks following major orthopedic surgery, compared with in-hospital prophylaxis for 7-15 days. Meta-analyses have confirmed that the size of the reduction is similar for both clinical and asymptomatic VTE. Vitamin K antagonists (VKAs) have been shown to be associated with significantly higher bleeding rates compared with LMWH when used as prolonged prophylaxis against VTE following major orthopedic surgery. Patients with cancer are a recognized group at high risk of VTE, and those undergoing major surgery for their malignancy are at particular risk. Evidence from clinical trials is amassing to show that prolonged prophylaxis with LMWH (dalteparin, enoxaparin) in these patients can significantly reduce the rate of postoperative VTE. In cancer patients with acute VTE, the traditional approach is to initiate acute treatment with unfractionated heparin or LMWH followed by long-term treatment with VKA to prevent recurrence. However, clinical trial data have confirmed that the LMWH dalteparin, when administered for 6 months, is significantly more effective than VKA in preventing recurrence, cutting the rate of VTE by 52% without increasing the risk of bleeding. A new and intriguing area of interest is whether LMWH can enhance survival in patients with cancer. Preliminary data suggest that a biological effect of LMWH may act to prolong survival in patients with cancer.

Low molecular weight heparins: a developmental perspective

Low molecular weight heparins (LMWHs) are now universally accepted as drugs of choice for post-surgical prophylaxis of deep vein thrombosis (DVT). Currently these agents are also being developed for the treatment of thrombosis and various cardiovascular indications. Due to manufacturing differences, each of the LMWHs exhibits a distinct pharmacological and biochemical profile. The specific activity of these agents in the anticoagulant assays ranges from 35 - 45 anti-IIa U/mg, whereas the specific activity in terms of anti-Xa units is designated as 80 - 145 anti-Xa U/mg. These LMWHs are capable of producing product-specific dose- and time-dependent antithrombotic effects in animal models of thrombosis. While the ex vivo effects are initially present at doses that are antithrombotic, these agents have been found to produce sustained antithrombotic effects without any detectable ex vivo anticoagulant actions. In experimental animal models and in various clinical trials, these agents have also been found to release tissue factor pathway inhibitor (TFPI) after both iv. and sc. administration. Repeated administration of LMWHs produces progressively stronger antithrombotic effects; however, the haemorrhagic responses vary and are largely dependent on the product used. The release of TFPI following iv. and sc. administration in a primate model also demonstrates product individuality and the relevance of this inhibitor to the actions of LMWHs. Furthermore, repeated administration, mimicking the post-surgical prophylaxis of DVT, leads to product-based augmentation of the antithrombotic or haemorrhagic effects. Antithrombotic and haemorrhagic studies are discussed, comparing the pharmacological profile of some of the available LMWHs. Product individuality, in terms of relative potency in different assays and the failure of standardisation protocols to provide any guidelines for product substitution and prediction of the clinical effects, is also addressed.

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.

The prevention of venous thromboembolism in older adults: guidelines

The rationale for thromboprophylaxis is based on the high prevalence of venous thromboembolism (VTE), a disorder involving deep vein thrombosis (DVT) and pulmonary embolism (PE), among hospitalized patients, the clinically silent nature of VTE in most patients, and the morbidity, cost, and potential mortality associated with unprevented thromboembolism. Both DVT and PE cause few specific symptoms, and the clinical diagnosis is unreliable. Since the first clinical manifestation of VTE may be fatal PE, it is inappropriate to wait for symptoms before treatment. Unrecognized and untreated DVT may also cause the postphlebitic syndrome and predispose patients to subsequent episodes of recurrent VTE. Routine screening for VTE has also not been shown to reduce the incidence of symptomatic VTE or fatal PE. Use of effective methods of prophylaxis is more cost effective and is safer than selective, intensive screening for VTE. This article reviews current recommendations for the prevention of VTE as they apply to older adults. The recommendations discussed are based on the Sixth American College of Chest Physicians Consensus Conference on Antithrombotic Therapy reported in Chest. 2001;119:132S-175S.