Efficacy and safety of a low-molecular-weight heparin and standard unfractionated heparin for prophylaxis of postoperative venous thromboembolism: European multicenter trial

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).

Low-molecular-weight heparin administered by subcutaneous catheter is a safe and effective anti-coagulation regimen in selected inpatient infants and children with complex congenital heart disease

BACKGROUND/HYPOTHESIS

Disadvantages of intravenous therapeutic unfractionated heparin, the first-line anti-coagulant agent in children with complex congenital heart disease, include unpredictable pharmacokinetics requiring frequent phlebotomies and the need for continuous intravenous access.

OBJECTIVE

To compare efficacy and safety of low-molecular-weight heparin administered by a subcutaneous indwelling catheter with intravenous unfractionated heparin.

MATERIALS AND METHODS

Clinical data from 31 inpatients prospectively enrolled to receive subcutaneous low-molecular-weight heparin were compared with those from a historical group of 44 inpatients receiving intravenous unfractionated heparin. Investigation of parents' satisfaction by telephone survey.

RESULTS

The percentage of anti-factor Xa levels outside therapeutic range was lower in the subcutaneous low-molecular-weight heparin group compared with the percentage of activated partial thromboplastin times outside therapeutic range in the intravenous unfractionated heparin group (40% versus 90%, p < 0.001). Neither group had a major complication. Transient local reactions occurred in 19% of patients of the subcutaneous low-molecular-weight heparin group. The number of needle punctures and that of placement of indwelling catheters were significantly lower in the subcutaneous low-molecular-weight heparin compared with the intravenous unfractionated heparin group (p < 0.001). In total, 84.2% of parents in the subcutaneous low-molecular-weight heparin group reported a positive experience when asked about comparison with prior intravenous unfractionated heparin treatment.

CONCLUSION

Subcutaneous low-molecular-weight heparin offers a safe anti-coagulation regimen for children with complex congenital heart disease providing more efficient therapeutic anti-coagulation and a reduction in needle punctures, thus causing less pain and anxiety in this children.

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.

Low-molecular weight vs. unfractionated heparin for prevention of venous thromboembolism in general surgery: a meta-analysis

To assess the association between low-molecular weight heparin (LMWH) and unfractionated heparin (UFH) in the prevention of venous thromboembolism (VTE) among participants undergoing general surgery. LMWH and UFH are the standard of practice in the prevention of VTE in surgery. However, in the context of general surgery, studies comparing the effectiveness of these treatments are limited. A systematic search was conducted to find studies which examined the comparative effectiveness between LMWH and UFH in the prophylaxis of VTE in the context of general surgery. The number of events of VTE in groups receiving LMWH or UFH was the primary outcome of interest, and was used to calculate odds-ratios. Amongst 33,068 participants pooled from twelve studies, the rate of VTE was 1.3% in those treated with LMWH, and 3.1% in those treated with UFH. Although there was a wide difference in rates due to clinical heterogeneity, there was no statistically significant difference between treatment effects [OR 0.77; 95% CI 0.58-1.03; p value = 0.0783; I²= 62.3%; 12 studies]. In terms of the sensitivity analysis, sources overly contributing to heterogeneity were removed. The random-effects model continued to show insignificance between LMWH and UFH in the prevention of VTE in participants undergoing general surgery [OR 0.86; 95% CI 0.69-1.08; p value = 0.2005; I²= 0%; 9 studies]. Results show an equal effectiveness in the prevention of VTE between participants undergoing general surgery in those allocated to receive LMWH to those allocated to receive UFH.

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.

Comparison of Venous Thromboembolism Prophylactic Measures Post Coronary Artery Bypass Graft Surgery

BACKGROUND

There is considerable debate surrounding venous thromboembolism (VTE) prophylaxis in patients post coronary artery bypass grafting (CABG) procedures. The American College of Chest Physicians guidelines report weak recommendations for starting VTE prophylaxis, but provide no specific guidance regarding timing or preferred prophylactic agent.

METHODS

This retrospective cohort study was designed to compare outcomes of post-cardiac surgery patients admitted to the cardiovascular intensive care unit (ICU) who received subcutaneous unfractionated heparin (UFH), with those who received subcutaneous enoxaparin for VTE prophylaxis. Between January 2013 and September 2017, 1085 patients were identified, and, after propensity score matching, 850 patients were selected for analysis. The primary outcomes were postoperative VTE and the occurrence of bleeding events up to 30 days postoperatively. Secondary outcomes included chest tube output, days mechanically ventilated, ICU length of stay, total hospital length of stay, and 30-day readmission rates.

RESULTS

During the study period, rates of 2.03% for VTE events and 1.38% for bleeding events were reported in the entire cohort. After matching, the rates of VTE events (2.12% vs. 1.41%, p = 0.43) and bleeding events (1.18% vs. 0.94%, p = 1.00) were more frequent in the heparin group versus the enoxaparin group; these differences were not statistically significant. However, we did find a statistically significant increase in several secondary endpoints, including chest tube output, days mechanically ventilated, ICU length of stay, and total hospital length of stay, within the heparin cohort. Bleeding rates were similar to those previously published, despite the early initiation of VTE prophylaxis.

CONCLUSIONS

We report no statistical difference in the rates of VTE or bleeding between chemical agents, but our results suggest enoxaparin may be a preferred agent over UFH.

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.

The long path to NOAC

The discovery of anticoagulant drugs occurred at a time when the process of blood coagulation only had been roughly described and their mode of action was unknown. Nevertheless, heparin – which was discovered 100 years ago – and warfarin – which was developed in the 1920s – had taken off on a triumphal course which is unique in medical history. The synthesis of anticoagulants with targeted mode of action was only achieved at the end of the last century, e. g. the inhibitor of factor Xa fondaparinux or the recombinant production of the direct thrombin inhibitor hirudin, closely followed by the synthesis of the direct oral inhibitors of factor Xa and thrombin. These compounds had been clinically developed in the early 21st century and meanwhile, they have become available for several indications. Dabigatran is the only thrombin inhibitor and rivaroxaban, apixaban and edoxaban are the three factor Xa inhibitors which entered the market and have started replacing the conventional anticoagulants for treatment of venous thromboembolic complications and for prevention of stroke in patients with atrial fibrillation. They have several characteristics in common such as a reproducible bioavailability, much shorter halflives than vitamin K antagonists, low interaction with other drugs, fixed dosing regimens without the necessity for routine coagulation controls and a better risk-/benefit profile than conventional anticoagulants. However, there are differences between the various compounds with regard to metabolism, renal elimination and the various dosing regimens which definitely need to be considered when prescribed to various patient populations.

Deep Vein Thrombosis Prophylaxis: Audit of Practice in General Surgical Patients in a Teaching Hospital

Objective:

To audit the prescription and implementation of deep vein thrombosis (DVT) prophylaxis in general surgical patients in a teaching hospital.

Methods:

All inpatients on three general surgical wards were audited for adequacy of prescription and implementation prophylaxis (audit A). A repeat audit 3 months later (audit B) closed the loop. The groups were compared using the chi-square test.

Results:

In audit A 50 patients participated. Prophylaxis was correctly prescribed in 36 (72%) and implemented in 30 (60%) patients. Eighteen patients at moderate or high risk (45%) received inadequate prophylaxis. Emergency admission, pre-operative stay and inadequate risk assignment were associated with poor implementation of protocol. In audit B 51 patients participated. Prescription was appropriate in 45 (88%) and implementation in 40 (78%) patients (p< 0.05). Eleven patients at moderate or high risk received inadequate prophylaxis. Seven of 11 high-risk patients in audit A (64%) received adequate prophylaxis, in contrast to all high-risk patients in audit B. The decision not to administer prophylaxis was deemed appropriate in 5 of 15 (30%) in audit A compared with 6 of 10 (60%) in audit B.

Conclusion:

Increased awareness, adequate risk assessment, updating of protocols and consistent reminders to staff and patients may improve implementation of DVT prophylaxis.

Heparin and related drugs for venous thromboembolism prophylaxis: subcutaneous or intravenous continuous infusion?

In this article, the most evidenced approaches of unfractionated heparin administration for prevention of venous thromboembolism in medical and surgical hospitalized patients will be reviewed. Present data were collected by searching Scopus, PubMed, MEDLINE, Science direct, Clinical trials and Cochrane database systematic reviews. Subcutaneous low doses of unfractionated heparin (10000–15000 IU) in two or three divided doses per day are commonly administrated for venous thromboembolism prevention in different medical and surgical populations. In some populations such as obese surgical and critically ill patients, due to altered pharmacokinetics behavior of unfractionated heparin, continuous intravenous infusion of the low doses of unfractionated heparin has been proposed.

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.

Diffuse alveolar hemorrhage associated with low molecular weight heparin

Diffuse alveolar hemorrhage (DAH) has a varied etiology, including anticoagulation drugs. There is conflicting evidence whether low molecular weight heparin (LMWH) has a low risk of bleeding complications compared to unfractionated heparin. We report here a case of DAH in a 74-year-old woman who was administered enoxaparin, a LMWH, after bilateral total knee arthroplasty. Although congestive heart failure after blood transfusion and fluid infusion could in part be associated with the bleeding, LMWH may be a major cause of DAH since the patient quickly recovered after its cessation. DAH should be of concern when acute respiratory failure with ground-glass shadow develops in both lungs during anticoagulation therapy with LMWH.

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.

Efficacy and Safety of Enoxaparin for Preventing Venous Thromboembolic Events following Urologic Laparoscopic Surgery

There is a paucity of definitive evidence that supports the use of enoxaparin to prevent venous thromboembolism (VTE) after urologic laparoscopic surgery. The purpose of this study was to evaluate the efficacy and safety of postoperative subcutaneous enoxaparin injection in patients who underwent urologic laparoscopic surgery. A total of 63 patients were evaluated from June 2010 to December 2012. All patients received postoperative prophylaxis with enoxaparin (2000 IU twice daily for 5 days). None of the patients treated with enoxaparin developed symptomatic VTE, but two cases (3.2%) of pulmonary embolism were noted before initial enoxaparin administration. Statistically significant differences were observed between the prothrombin time (PT) and activated partial thromboplastin time (APTT) values and D-dimer levels obtained at baseline and on day 7 after surgery; however, the PT and APTT values did not exceed the normal range. In addition, signs of any adverse events were not encountered in any of the patients treated with enoxaparin. The use of enoxaparin immediately after a surgery may confer valuable thromboprophylaxis benefits for urologic laparoscopic surgery.

The mechanisms of nadroparin-mediated inhibition of proliferation of two human lung cancer cell lines

OBJECTIVES

Clinical data suggest that heparin treatment improves survival of lung cancer patients, but the mechanisms involved are not fully understood. We investigated whether low molecular weight heparin nadroparin, directly affects lung cancer cell population growth in conventionally cultured cell lines.

MATERIALS AND METHODS

A549 and CALU1 cells' viability was assessed by MTT and trypan blue exclusion assays. Cell proliferation was assessed using 5-bromo-2-deoxyuridine incorporation. Apoptosis and cell-cycle distribution were analysed by flow cytometry; cyclin B1, Cdk1, p-Cdk1 Cdc25C, p-Cdc25C and p21 expressions were analysed by western blotting. mRNA levels were analysed by real time RT-PCR.

RESULTS

Nadroparin inhibited cell proliferation by 30% in both cell lines; it affected the cell cycle in A549, but not in CALU-1 cells, inducing arrest in the G(2) /M phase. Nadroparin in A549 culture inhibited cyclin B1, Cdk1, Cdc25C and p-Cdc25C, while levels of p-Cdk1 were elevated; p21 expression was not altered. Dalteparin caused a similar reduction in A549 cell population growth; however, it did not alter cyclin B1 expression as expected, based on previous reports. Fondaparinux caused minimal inhibition of A549 cell population growth and no effect on either cell cycle or cyclin B1 expression.

CONCLUSIONS

Nadroparin inhibited proliferation of A549 cells by inducing G(2) /M phase cell-cycle arrest that was dependent on the Cdc25C pathway, whereas CALU-1 cell proliferation was halted by as yet not elucidated modes.

Low molecular weight heparin in prophylaxis of deep vein thrombosis in Asian general surgical patients: A Kashmir experience

BACKGROUND AND OBJECTIVES

Deep vein thrombosis (DVT) occurs at a lower rate in Asia than in the rest of the world. We wanted to study the significance and efficacy of low molecular weight heparin (LMWH) in prophylaxis of DVT in major general surgical patients in the Kashmir Valley (India, Asia) so as to make it a routine in our patients.

PATIENTS AND METHODS

This was a prospective study in which the effect of LMWH was compared with no prophylaxis.

RESULTS

LMWHs are more effective than no prophylaxis in the prevention of DVT and pulmonary thromboembolism in highest-risk general surgical patients (odds ratio = 16.64; 95% confidence interval = 3.63-1130.03; P-value = 0.014).

CONCLUSION

LMWHs have a significant prophylactic effect on DVT in general surgical patients, with a higher benefit to risk ratio, and, in spite of the low incidence of DVT in Asia, its prophylaxis should routinely be considered in this part of the world as well, preferably in the form of LMWHs.

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.

Hepatic veins as a site of clot formation following liver resection

Pulmonary embolism occurs more frequently after hepatectomy than previously thought but is infrequently associated with peripheral deep vein thrombosis. In this paper, we report 2 cases of postoperative hepatic vein thrombosis after liver resection. Both patients had undergone major hepatectomy of a non-cirrhotic liver largely exposing the middle hepatic vein. Clots were incidentally found in the middle hepatic vein 4 and 17 d after surgery despite routine systemic thrombo-prophylaxis with low molecular weight heparin. Coagulation of the transition plan in a context of mutation of the prothrombin gene and inflammation induced biloma were the likely predisposing conditions. Clots disappeared following curative anticoagulation. We conclude that thrombosis of hepatic veins may occur after liver resection and is a potential source of pulmonary embolism.

Safety and efficacy of lower-dose unfractionated heparin for prophylaxis of deep vein thrombosis and pulmonary embolism in an Asian population

The objective of this study is to analyze the tolerance and efficacy of the subcutaneous administration of a reduced 2,500-unit low-dose unfractionated heparin given for an efficacious, yet Asian population-sensitive, prophylaxis for deep vein thrombosis and fatal pulmonary embolism. Eighty-seven Japanese patients were operated on either for abdominal or pelvic complications or both, as well as for gynecologic conditions including ovarian, cervical, and corpus cancers. Thirty-two of the patients were administered the experimental low dose of unfractionated calcium heparin for prophylaxis. The 2,500 units of low-dose unfractionated heparin were given subcutaneously 2 h preoperatively and again 12 h postoperatively. Other standard methods of mechanical prophylaxis, including graduated compression stockings and intermittent pneumatic compression, were performed. Fifty-five of the patients were not administered heparin, but did receive the same standard mechanical graduated compression stockings and intermittent pneumatic compression prophylaxis. We compared the surgical and postsurgical complications noted for low-dose unfractionated heparin patients with the results of those who received no heparin prophylaxis and analyzed this data using the Mann-Whitney U-test. There was no significant difference in the mean of the blood loss volumes. There were also no significant differences found in the perioperative bleeding complications between the two groups. However, three (3/55; 6%) of the patients in the no-heparin group suffered a symptomatic pulmonary embolism, although none were fatal. There were no pulmonary embolism onsets in the heparin prophylaxis group. We feel that we have provided evidence that several serious complications, such as perisurgical hemorrhage, deep vein thrombosis, fatal pulmonary embolism, and increased postoperative recovery times, can be prevented by prophylaxis with 2,500-unit low-dose unfractionated heparin.

Risk-based evaluation of thromboprophylaxis among surgical inpatients: are low risk patients treated unnecessarily?

BACKGROUND

Venous thromboembolism is a common source of morbidity and mortality but a variety of preventative measures are available.

AIMS

To audit the current practice of thromboprophylaxis and compare against published protocols.

METHODS

Three-hundred and seventy-six (376) surgical patients were surveyed prospectively. A Performa was completed recording the presence of up to 11 risk factors. A risk score was calculated and the use of specific thromboprophylatic measures identified.

RESULTS

Heparin thromboprophylaxis was widely used, eight patients (who were on aspirin therapy) failed to receive any prophylaxis (risk factors 4-6). In addition there were 60 patients at low risk (risk score <2) received LMWH from which they were unlikely to benefit.

CONCLUSIONS

Thromboembolic prophylaxis is widely but unselectively applied. Adoption of a risk: benefit ratio approach should ensure those who would benefit from thromboprophylaxis are adequately treated while those in whom thromboprophylaxis is not indicated are spared unnecessary therapy.

Thromboprophylaxis in major abdominal surgery for cancer

AIMS

To review the epidemiology and pathogenesis of venous thromboembolism (VTE) in surgical cancer patients, in addition to the use of thromboprophylaxis in major abdominal surgery, such as low-molecular-weight heparin (LMWH) and fondaparinux.

METHODS

Systematic review of the literature, focussing on risk factors for VTE, parenteral methods of thromboprophylaxis, approaches to prolonged prophylaxis, and effects on patient survival.

FINDINGS

Patients with cancer undergoing abdominal surgery are at substantially higher risk for VTE than patients without cancer. Furthermore, prolonged thromboprophylaxis for up to 4 weeks is more effective than short-term administration in these high-risk patients. The concurrent use of graduated compression stockings has a synergistic effect on the reduction in VTE risk.

CONCLUSIONS

Thromboprophylaxis with LMWH has been shown to minimise the incidence of thromboembolic events, and is a well-established therapy worldwide. The American College of Chest Physicians recommends the routine use of thromboprophylaxis, with LMWH or unfractionated heparin, in patients with cancer who are undergoing surgical procedures, and the appropriate use of these thromboprophylactic agents has significant implications for the clinical care and quality of life of surgical patients with cancer.

Perioperative complications of radical retropubic prostatectomy

The opinions and assertions contained herein are the private views of the authors and are not to be construed as reflective of the views of the US Army or the Department of Defense. Radical retropubic prostatectomy has long been considered one of the most difficult procedures in the urologist's armamentarium. Therefore, we performed a thorough review of recent literature regarding intraoperative and postoperative complications. The intent of this effort is to review established data regarding the most frequently seen complications and to highlight recent developments regarding the prevention or treatment of such complications.

Antithrombotic Strategies in Vascular Surgery: Evidence and Practice

BACKGROUND

The aim of this study was to evaluate the current practice of peri and postoperative antithrombotic therapy in vascular surgery in Austria and to compare this with the results of randomised prospective clinical trials.

METHODS

A questionnaire assessing intra, postoperative and long-term antithrombotic treatment in 13 different surgical procedures (three supra-aortic, three aorto-iliac reconstructions and seven inguinal and infra-inguinal arterial reconstructions) was sent to all 22 institutions training vascular surgical fellows in Austria.

RESULTS

Intraoperative antithrombotic therapy was quite consistently performed with unfractionated heparin (UFH) with or without acetylsalicylic acid (ASA). Early and long-term postoperative therapy differed considerably. Most centres used low molecular weight heparin (LMWH) for early postoperative therapy after vascular reconstructions, in > 75% combined with ASA and/or clopidogrel. Long-term therapy consisted of antiplatelet agents in all centres. Vascular grafts were anticoagulated with UFH in 25% of the centres in the early postoperative period, the remaining institutions used LMWH +/- antiplatelet agents. For long-term antithrombotic therapy cumarins were used in 75% of the centres, predominantly for venous grafts. Distal prosthetic grafts were mainly treated with antiplatelet agents. Intraoperative antithrombotic therapy was in accordance to present guidelines, postoperative antithrombotic therapy, however, differed considerably between the participating institutions and the results of available controlled studies.

CONCLUSION

Optimal antithrombotic strategies during and after vascular surgery are still under debate, and current practice often differs from available evidence. Vascular surgical societies should be encouraged to define recommendations on antiplatelet therapy and anticoagulation for different vascular interventions.

Prophylaxis and treatment of deep vein thrombosis in general surgery

BACKGROUND

Patients undergoing general surgery present an inherent risk of deep vein thrombosis (DVT). Evidence-based strategies for prevention and treatment of DVT should be continuously upgraded on the basis of good-quality recent trials.

DATA SOURCES

Articles were identified using MEDLINE, EMBASE, and the Cochrane Library databases (January 1980 to July 2003). Randomized clinical trials and meta-analyses in which different prophylactic and treatment methods were compared for general surgery patients were selected.

CONCLUSIONS

In general surgery, low-molecular weight heparins (LMWHs) are relied upon more and more for prophylaxis and initial anticoagulant treatment of DVT, because of their multiple advantages in efficacy, safety, and convenience in handling. For cost-effective reasons, full-dose vitamin K antagonists are still preferred as the standard long-term anticoagulation method, while LMWHs represent the exception. Long-term use of low-intensity warfarin should be considered a new standard of care for the management of venous thrombosis. Compared to LMWH, the new anticoagulant molecules fondaparinux and ximelagatran seem to have similar efficacy in the treatment of venous thromboembolism, but they have a 2-fold increased efficacy in its prophylaxis. Clinical implementation of these new anticoagulant molecules depends on their cost-effectiveness; however, they have the potential to become the treatment of choice in the next decade. Thrombolysis has an unacceptable risk of hemorrhagic complications when used in the treatment of postoperative DVT. Furthermore, there are no data to prove that thrombolysis reduces the incidence of postthrombotic syndrome (PTS), despite early and complete recanalization achieved by thrombolysis. Surgical thrombectomy is only meant to decompress the venous hypertension consecutive to massive thrombosis (phlegmasia cerulea dolens) and thus to avoid venous gangrene. Other mechanical percutaneous thrombectomy devices are under evaluation. In selected cases, a combination treatment consisting of locoregional thrombolysis of the crurofemoral venous axis and mechanical thrombectomy of the pelvic venous axis achieves high rates of complete desobliteration.

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.

Hématomes musculaires spontanés chez les patients hémiplégiques sous traitement anticoagulant

INTRODUCTION

Muscular hematomas are frequently reported as a complication of anticoagulation therapy.

METHODS

We report six cases of spontaneous muscular hematomas occurring in hemiplegic patients receiving anticoagulation therapy using heparin, low-molecular-weight heparin or fluindione. Anticoagulation therapy was given in prophylactic doses to two patients to prevent deep vein thrombosis and in therapeutic doses to four patients with deep vein thrombosis, pulmonary embolism or cardiac arrhythmia. Two patients experienced episodes of bleeding when heparin and fluindione were temporarily associated.

RESULT

Contrary to previous reports, the more frequent site of bleeding was not the ilio-psoas muscle (only 2 patients); hematomas were also observed in hip adductors and gluteus muscles. The most striking finding was the constant location of the hematoma on the hemiplegic side.

CONCLUSION

Location on the hemiplegic side can lead to underestimating the frequency of neurologic compression by the hematoma; the diagnosis can nevertheless be established by electromyography. Local signs may not be present, but general signs of hypovolemia and anemia are more frequent. Ultrasound may be the first line investigation but in our experience, the results can be misleading and computed tomography (CT) or MRI are often required to confirm the diagnosis.

Postoperative nadroparin administration for prophylaxis of thromboembolic events is not associated with an increased risk of hemorrhage after spinal surgery

AIM

To determine the risk of postoperative hemorrhage during a 3-year period of early postoperative administration of nadroparin (Fraxiparin) plus compression stockings in a large cohort of patients who underwent spinal surgery.

METHODS

A total of 1,954 spinal procedures at different levels (503 cervical, 152 thoracic and 1,299 lumbar), performed between June 1999 and 2002 at the Department of Neurosurgery, Johann-Wolfgang-Goethe University Frankfurt, were included in this study. To prevent venous thromboembolic events (VTE), all patients were routinely treated subcutaneously with 0.3 ml of early (less than 24 h) postoperative nadroparin calcium (Fraxiparin) (2850 IU anti-Xa, Sanofi Winthrop Industrie, France) plus intra- and postoperative compression stockings until discharge. The occurrence of a postoperative hematoma (defined as a hematoma requiring surgical evacuation because of space occupation and/or neurological deterioration) and a deep venous thrombosis (DVT) were recorded in a database and analyzed retrospectively.

RESULTS

13 (0.7%) of the 1,954 spinal operations were complicated by major postoperative hemorrhages. In 5 of the 13 patients (38.5%) the hemorrhage occurred on the day of surgery before the administration of nadroparin. Thus, the hemorrhage rate of patients receiving nadroparin was 0.4% (8/1,949). Ten (77%) of the 13 patients with major postoperative hematoma showed a progressive neurological deficit, which resolved in 6 patients and resulted in a hematoma-related morbidity of 31% (4/13). Only 1 patient (0.05%) in this series developed a clinically evident DVT, and none of the patients suffered from pulmonary embolus during the hospital stay.

CONCLUSION

Although retrospective, this is to date the largest study providing information about the hemorrhage rate associated with early postoperative anticoagulation following spinal surgery. The results confirm that early postoperative pharmacological thromboembolic prophylaxis using nadroparin in patients with spinal surgery is not associated with an increased risk of postoperative hemorrhage.

Risk of Postoperative Hemorrhage after Intracranial Surgery after Early Nadroparin Administration: Results of a Prospective Study

OBJECTIVE

Early postoperative pharmacological prophylaxis of deep vein thrombosis after intracranial surgery is still a matter of debate because of concerns regarding the formation of postoperative hematoma. The objective of this study was to prospectively analyze the rate of postoperative hemorrhage during a 3-year period of early postoperative administration of the low molecular weight heparin nadroparin (Fraxiparin) plus compression stockings in a large cohort of patients undergoing intracranial surgery.

METHODS

A total of 2823 intracranial neurosurgical procedures, performed between June 1999 and 2002, were studied. Of these operations, 1319 (46.7%) were major intracranial surgical procedures (Group 1). Group 2 comprised 1504 operations (53.3%) considered to be minor surgical procedures (e.g., shunt procedures, biopsies). All patients except those with transnasal transsphenoidal removal of pituitary tumors underwent early postoperative imaging (computed tomography or magnetic resonance imaging) to determine postoperative hemorrhage. All significant postoperative hematomas (defined as those requiring surgical evacuation because of relevant space occupation and/or neurological deterioration) were treated surgically. Prophylaxis of venous thromboembolic events included early (&lt;24 h) postoperative administration of 0.3 ml nadroparin subcutaneously plus intra- and postoperative compression stockings until discharge.

RESULTS

Forty-three major postoperative hemorrhages (1.5%) were observed after 2823 intracranial procedures (95% confidence interval, 1.1–2.05). Forty-two (3.2%) of 1319 postoperative hematomas occurred in patients undergoing major intracranial procedures (Group 1). There was only 1 (0.07%) significant hemorrhage after 1504 minor intracranial procedures (Group 2). A subgroup analysis of patients who needed preoperative anticoagulation because of medical comorbidity did not reveal an increased frequency of postoperative hematoma when anticoagulation was stopped 24 hours before surgery P = 0.1, χ2 test; 95% confidence interval, 0.89–3.0).

CONCLUSION

This report describes the largest prospective study conducted to date to determine the hemorrhage rate after early postoperative anticoagulation. The results support the concept of postoperative pharmacological thromboembolic prophylaxis in patients undergoing intracranial surgery.

Laparoscopic Gastric Bypass Surgery: Equipment and Necessary Tools

Advanced laparoscopy in the morbidly obese patient is technically challenging. Having the proper instrumentation and equipment available is a major component of technical success. Items routinely used during surgery performed on patients of normal size must often be modified or substituted when morbidly obese patients undergo surgery. In this article, we review the specific tools necessary for the safe and proper completion of laparoscopic Roux-en-Y gastric bypass, in addition to various alternatives that can be helpful when other procedures are performed on morbidly obese patients.

Thromboprophylaxis and thrombosis in medical, surgical, trauma, and obstetric/gynecologic patients

The International Consensus and the ACCP Sixth Consensus had a great impact on the clinical acceptance of LMWHs. These recommendations have been instrumental in initiating further clinical trial to answer key questions regarding thromboprophylaxis and in setting a new standard for patient care. Also, the key to cost containment in management of DVT/PE is to (1) define the etiology (blood coagulation protein or platelet defect), institute appropriate long-term therapy as indicated, and assess appropriate family members as indicated if a hereditary defect is found and (2) use LMWH as inpatient management. saving a minimum of 210,000.00 dollars per 1000 patients simply from cost savings of recurrence, saving 17 lives per 1000 patients, and saving exorbitant costs of care for patients with recurrence and development of chronic venous insufficiency. The use of outpatient LMWH will save 4,900,000.00 dollars per 1000 patients if applied to the 70% of patients with DVT who fit the criteria of no comorbid condition requiring hospitalization and who arrive early enough to allow a diagnosis to be sent home or hospitalized for 24 hours or less. The simple defining of defects leading to unexplained thrombosis will add another 3,000,000.00 dollars in savings per 1000 patients with DVT and approximately 350,000.00 dollars per 100 patients with thrombotic stroke. In those with transient ischemic attacks, defining the defect and instituting appropriate antithrombotic therapy, thereby potentially saving approximately 30% from developing a thrombotic stroke, amounts to approximately 350,500.00 dollars (= 30% of 1,168,500.00 dollars) in savings per 100 patients.

DVT prophylaxis and anticoagulation in the surgical patient

One of the most common postoperative complications is venous thromboembolism, a term encompassing deep vein thrombosis and pulmonary embolism. This article reviews the epidemiology, natural history, difficulties in diagnosis, and strategies for the prevention of postoperative venous thromboembolism. We thoroughly review the currently available methods for thromboprophylaxis including: early ambulation, elastic compression stockings, pneumatic compression devices, inferior vena cava filters, and a variety of pharmacologic agents such as unfractionated heparin, warfarin, aspirin, low molecular weight heparin, and pentasaccharides. Finally, we review the perioperative management of patients on long-term oral anticoagulation.

Reviparin: a review of its efficacy in the prevention and treatment of venous thromboembolism

Reviparin (reviparin sodium) is a low molecular weight heparin (LMWH) that catalyses the inactivation of factors Xa and IIa by binding to antithrombin, which ultimately leads to the inhibition of the clotting cascade. It is administered subcutaneously. Reviparin 7,000 to 12,600 anti-XaIU/day was found to be as effective as intravenous unfractionated heparin in preventing the clinical recurrence of acute deep vein thrombosis (DVT) and/or pulmonary embolism in 1 large randomised, multicentre trial (COLUMBUS) and was significantly more effective than intravenous unfractionated heparin in the prevention of recurrent venous thromboembolism in another large randomised, multicentre trial (CORTES). Reviparin has also been compared with unfractionated heparin in children with established DVT. However, the trial was under-powered and no conclusion could be made regarding comparative efficacy. As prophylaxis, reviparin 1,750 anti-XaIU once daily was as effective as unfractionated heparin 5,000IU twice daily in 1,311 patients undergoing abdominal surgery and, in a once daily dosage of 4,200 anti-XaIU, was as effective as subcutaneous enoxaparin sodium 40 mg/day or acenocoumarol in patients undergoing hip replacement surgery. Reviparin 1,750 anti-XaIU also effectively prevented DVT. compared with no treatment, in patients undergoing knee arthroscopy. It was also more effective than placebo in patients with brace immobilisation of the lower extremity. Reviparin was compared with 'standard care' in children with central venous lines. However, the trial was too small to make conclusions regarding its efficacy. Comparative data indicate that reviparin is at least as well tolerated as heparin and enoxaparin sodium. However, in a large (n = 1,279) trial there were significantly fewer major bleeding episodes in patients receiving reviparin than in patients given the oral anticoagulant acenocoumarol. The most commonly reported adverse events in therapeutic trials have been intraoperative blood loss and postoperative bleeding complications such as wound haematoma, bruising and injection site haemorrhage. Reviparin was also well tolerated in 2 studies in children aged < or = 16 years.

CONCLUSION

Reviparin has shown efficacy in the treatment of established DVT and in the prevention of postoperative DVT after moderate and high risk surgery and was as effective as enoxaparin sodium or acenocoumarol in patients undergoing hip replacement surgery. As an effective and well tolerated antithrombotic agent, reviparin is likely to assume a significant role in the treatment and prevention of DVT, as it appears to have a preferable tolerability profile to subcutaneous heparin after moderate risk surgery and is at least as effective as intravenous heparin in the treatment of established DVT.

Clinical experiences with low-molecular weight heparins in pediatric patients

The courses of 79 children (2 weeks to 19 years old) treated with two different low-molecular weight heparins (LMWHs)--nadroparin (n=66) and enoxaparin (n=13)--were retrospectively analysed. In 62 patients, LMWHs were given for short-term prophylaxis (1-2 weeks) during immobilization after surgery or trauma. Thirteen children with thromboembolic events received long-term prophylaxis with LMWHs for 2-18 months--six after thrombolytic therapy and seven after therapy with unfractionated heparin (UFH). Because of thromboembolic events, four patients were initially treated with LMWHs. In all patients with short-term prophylaxis, no thrombosis occurred. After thrombolytic therapy, three children had no reocclusion, two had no thrombus apposition and one had complete recanalization. In the seven patients treated with LMWHs after UFH, four had no reocclusion, two had recanalization and one had reocclusion. In all patients receiving LMWHs for initial treatment of thrombosis, no thrombus apposition, but also no recanalization, occurred. For short-term prophylaxis, nadroparin was used independent of the body weight and without determination of anti-factor Xa (anti-FXa) activity. Long-term prophylaxis was given mainly as doses of 45-100 anti-FXa U/kg resulting in anti-FXa activities between 0.2 and 0.4 U/ml. For treatment of thrombosis, doses of 200-300 anti-FXa U/kg corresponded to 0.5-1.0 anti-FXa U/ml. Side effects--slight gastrointestinal bleeding and temporary reversible hair loss--were seen in two patients. In conclusion, LMWHs proved to be efficacious and safe especially in prophylaxis of thromboembolic events in children.

Meta-analysis of low molecular weight heparin in the prevention of venous thromboembolism in general surgery

BACKGROUND

Low molecular weight heparins (LMWHs) have become routine thromboprophylaxis in general surgery. However, their actual clinical effect, its magnitude relative to that of unfractionated heparin (UFH), and the optimal dose are still debated.

METHODS

A meta-analysis was performed of all available randomized trials in general surgery comparing LMWH with placebo or no treatment, or with UFH.

RESULTS

Comparison versus placebo or no treatment confirmed that the significant reduction in asymptomatic deep vein thrombosis (DVT) obtained with LMWH (n = 513; relative risk (RR) 0.28 (95 per cent confidence interval 0.14-0.54)) was associated with a significant reduction in clinical pulmonary embolism (n = 5456; RR 0.25 (0.08-0.79)) and clinical venous thromboembolism (VTE) (n = 4890; RR 0.29 (0.11-0.73)), and a trend towards a reduction in overall mortality rate. Comparison versus UFH showed a trend in favour of LMWH, with a significant reduction in clinical VTE (P = 0.049), a trend also found for cancer surgery. LMWH at doses below 3400 anti-Xa units seemed to be as effective as, and safer than, UFH, while higher doses yielded slightly superior efficacy but increased haemorrhagic risk, including that of major haemorrhage.

CONCLUSION

Asymptomatic DVT may be regarded as a reliable surrogate endpoint for clinical outcome in studies investigating thromboprophylaxis in general surgery. LMWH seems to be as effective and safe as UFH. Determination of the optimal dose regimen of LMWH for this indication requires further investigation.