[Prevention of intraoperative venous thromboembolism: what are the American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th edition)?]. / Prévention de la maladie thrombo-embolique veineuse péri-opératoire : que disent les 8es recommandations de l'American College of Chest Physicians ?

Extensive evidence related to thromboembolism risk and its prevention are available to guide health care providers. The 8th ACCP Evidence-Based Clinical Practice Guidelines were published in June 2008. The chapter on venous thromboembolism prophylaxis is the result of the collaboration of six senior authors with expertise in thrombosis, surgery, medicine, and critical appraisal. The methodology and the philosophy of these guidelines are explained in this paper and the major recommendations dealing with perioperative thromboprophylaxis are summarized.

Giant cell arteritis and cardiovascular disease in older adults.

OBJECTIVE: To explore the association between giant cell arteritis (GCA) and subsequent cardiovascular disease in older adults. DESIGN: Population based retrospective cohort study. SETTING: The entire province of Ontario, Canada. PARTICIPANTS: Patients aged 66 years and older with newly diagnosed GCA (n = 1141), osteoarthritis (n = 172,953), or neither (n = 200,000). Patients with neither were randomly selected from the general population and formed the control group. MAIN OUTCOME MEASURES: The primary composite outcome was based on a subsequent diagnosis or surgical treatment for coronary artery disease, stroke, peripheral arterial disease, or aneurysm or dissection of the aorta. RESULTS: The composite end point was more common in seniors with GCA (12.1/1000 person-years) than in patients with osteoarthritis (7.3/1000 person-years) or neither condition (5.3/1000 person-years). The adjusted hazard ratio for cardiovascular disease was 1.6 (95% confidence interval (CI) 1.1 to 2.2) in patients with GCA versus patients with osteoarthritis, and 2.1 (95% CI 1.5 to 3.0) in patients with GCA versus unaffected controls. CONCLUSIONS: Older adults with GCA appear to be at increased risk for developing cardiovascular disease. Whether an aggressive approach to cardiovascular risk factor modification is particularly beneficial in these patients remains to be determined.

Underlying chronic granulomatous disease in a patient with bronchocentric granulomatosis.

We present a case of bronchocentric granulomatosis in a woman with no history of asthma who was colonised with Aspergillusfumigatus. A family history of chronic granulomatous disease prompted further testing that demonstrated severely depressed neutrophil oxidant production and gp91(phox) deficiency compatible with the X linked carrier state of chronic granulomatous disease. Only one report of the association of these two rare diseases has previously appeared in the literature. We postulate that an ineffective immune response led to the prolonged colonisation of Afumigatus resulting in a hypersensitivity reaction that was manifest clinically as bronchocentric granulomatosis.

Deep vein thrombosis and its prevention in critically ill adults.

BACKGROUND: Our objective was to systematically review the incidence of deep vein thrombosis (DVT) and the efficacy of thromboprophylaxis in critically ill adults, including patients admitted to intensive care units and following trauma, neurosurgery, or spinal cord injury. METHODS: Two authors independently searched MEDLINE, EMBASE, abstract databases, and the Cochrane database. Data were extracted independently in triplicate. RESULTS: Ten percent to 30% of medical and surgical intensive care unit patients develop DVT within the first week of intensive care unit admission. The use of subcutaneous low-dose heparin reduced the rate by 50% compared with no prophylaxis. Approximately 60% of trauma patients developed DVT within the first 2 weeks of admission. Use of unfractionated heparin appears to decrease the incidence of DVT by only 20%, whereas low-molecular-weight heparin decreases the incidence by a further 30%. The estimated prevalence of DVT in neurosurgical patients not given prophylaxis is 22% to 35%. Mechanical prophylaxis is efficacious, with a pooled odds ratio in 5 randomized trials of 0.28. Use of low-molecular-weight heparin has been investigated as an adjunct to mechanical prophylaxis with a pooled odds ratio of 0.59 compared with graduated compression stockings alone. The incidence of DVT without prophylaxis in acute spinal cord injury patients is likely in excess of 50% to 80%. Studies of prophylaxis in these patients are too sparse to come to any definitive conclusion. CONCLUSIONS: Critically ill patients commonly develop DVT, with rates that vary from 22% to almost 80%, depending on patient characteristics. Methods of prophylaxis proven in one group do not necessarily generalize to other critically ill patient groups. More potent prophylactic regimens other than unfractionated or low-molecular-weight heparins alone may be needed with higher-risk groups.

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

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

The risk of venous thromboembolism is increased throughout the course of malignant glioma: an evidence-based review.

BACKGROUND: Venous thromboembolism (VTE) frequently complicates the course of patients with cancer, and there is evidence to suggest that patients with brain tumors are at particularly high risk. The objective of this methodology-based literature review was to quantify the rate of incidence of VTE in patients with malignant glioma and to determine the factors that predict an increased risk of this complication. METHODS: Studies meeting predefined inclusion criteria were evaluated independently on an eight-item methodology index by three raters. Authors were contacted to resolve ambiguities. The results of the studies were summarized and the incidence rate of VTE within the early postoperative phase and during extended follow-up were reported separately. RESULTS: Within 6 weeks after surgery the incidence rate of deep venous thrombosis (DVT) ranged from 3% to 60%, varying with the prophylaxis regimen used, the method of diagnosis, and the study design. Beyond 6 weeks postoperatively, the rates of DVT ranged from 0.013 to 0.023 per patient-month of follow-up. The single study with no significant methodologic deficiencies found a 24% rate of incidence of symptomatic DVT over the 17 months of follow-up beyond the first 6 postoperative weeks. In 6 studies the presence of leg paresis, histologic diagnosis of glioblastoma multiform, age >/= 60 years, large tumor size, use of chemotherapy, and length of surgery > 4 hours were identified as possible risk factors. CONCLUSIONS: The incidence of VTE is high throughout the course of malignant glioma. A randomized, controlled trial is needed to clarify whether the benefits of long term anticoagulant prophylaxis outweigh the risks and costs of such therapy.

The management of asthma: a case-scenario-based survey of family physicians and pulmonary specialists.

This study assessed family physicians' and pulmonary specialists' approaches to the treatment of adult outpatient asthma using a self-administered questionnaire consisting of six asthma scenarios of varying severity levels. One hundred sixty-three randomly selected family physicians and pulmonary specialists completed the questionnaire (response rate of 80%). We observed that, regardless of asthma severity, more than 75% of physicians (regardless of specialty) would not include oral theophylline or nonsteroidal anti-inflammatory preparations in their treatment approach. Pulmonary specialists' and family physicians' approaches to mild asthma were similar (more than 90% recommended an inhaled beta2-agonist). However, considerable differences existed among and between physician groups for the remaining scenarios. For example, with an exacerbation associated with an upper respiratory tract infection, family physicians were more likely to recommend oral antibiotics (p<0.0001) and a same-day outpatient visit (p<0.0001), whereas specialists were more likely to increase the inhaled corticosteroid dosage (p<0.0001). Overall, disagreement was observed almost twice as often among family physicians than among specialists. Our results suggest that physicians vary markedly in their reported use of most interventions available to treat asthma, even when the disease severity is specified.

Allogeneic red blood cell transfusion is an independent risk factor for the development of postoperative bacterial infection.

BACKGROUND AND OBJECTIVES: Allogeneic red blood cell transfusions may exert immunomodulatory effects in recipients including an increased rate of postoperative bacterial infection. It is controversial whether allogeneic transfusion is an independent predictor for the development of postoperative bacterial infection. METHODS: We analysed a prospectively collected database of 1,349 patients undergoing colorectal surgery in 11 centres across Canada. The primary outcome was the development of either a postoperative wound infection or intra-abdominal sepsis in transfused and nontransfused patients. The effect of allogeneic transfusion on postoperative infection was evaluated with adjustment for all the confounding factors in a multiple regression analysis. RESULTS: The 282 patients who received a total of 832 allogeneic units had a significantly higher frequency of wound infections and intra-abdominal sepsis than the patients who were not transfused (25. 9 vs. 14.2%, p = 0.001). A significant dose-response relationship between transfusion and infection rate was demonstrated. Multiple regression analysis identified allogeneic transfusion as a statistically significant independent predictor for postoperative bacterial infection (OR 1.18, 95% CI 1.05-1.33, p = 0.007). Other independent predictors were anastomotic leak, repeat operation, patient age and preoperative haemoglobin level. The mortality rate was also significantly higher in the transfused group. CONCLUSION: These data support the hypothesis that allogeneic red cell transfusion is an independent risk factor for the development of postoperative bacterial infection in patients undergoing colorectal surgery. This association provides further reason to minimise exposure to allogeneic transfusions in the perioperative setting.

Venous thromboembolism: risk factors and prophylaxis.

Venous thromboembolism is a common disease in the community and the most frequent preventable cause of hospital death. Acquired and inherited risk factors for thrombosis have been extensively studied over the past two decades. These factors and the clinical setting allow the stratification of most hospitalized patients into low-, moderate-, and high-risk groups. For patients in the moderate- and high-risk categories, routine thromboprophylaxis can decrease the morbidity and mortality from thromboembolic complications as well as reduce patient care expenditures. Low-dose heparin is generally the most appropriate prophylaxis for moderate-risk patients, and either low molecular weight heparin or adjusted-dose warfarin is generally the most appropriate for high-risk patients.

Physicians' approaches to providing asthma education to patients and the level of patient involvement in management decisions.

The objectives of this study were to describe physicians' self-reported approaches to providing disease-specific education to adults with asthma in an outpatient setting and their opinions about the level of patient involvement in management decisions. A mailed questionnaire was completed by 163 randomly selected physicians, representing an 80% response rate. The educational actions provided most frequently included information about prescribed medications (90%-100% of physicians), general asthma information (87%-98%), and inhaler demonstration (85%-95%). Educational activities provided least frequently were action plans (7%-74%) and referral to a nonprofit community asthma organization for further information (18%-36%). The reported provision of asthma education was related to patients' asthma severity (p < 0.0001) and physician specialty (p < 0.005). Physicians indicated that their patients were less involved in asthma management decisions than they would prefer (p < 0.001). The results suggest that physicians vary markedly in their approaches to providing asthma education to patients. Future descriptive and intervention studies are needed to identify the most effective models for providing education and patient involvement.

The incidence of symptomatic venous thromboembolism during and after prophylaxis with enoxaparin: a multi-institutional cohort study of patients who underwent hip or knee arthroplasty. Canadian Collaborative Group.

BACKGROUND: Despite low molecular weight heparin prophylaxis, the incidence of venographically detected, residual deep vein thrombosis after hip and knee arthroplasty remains high, at approximately 15% and 30%, respectively. Most of these thrombi are asymptomatic and of unknown clinical significance. Nevertheless, because they have the potential to grow, limiting prophylaxis to the in-hospital period may provide inadequate protection. METHODS: We studied a cohort of 1984 consecutive patients who had hip or knee arthroplasty at 1 of 28 participating hospitals. Patients received enoxaparin prophylaxis, 30 mg subcutaneously every 12 hours for up to 14 days, and underwent predischarge compression ultrasonography. Study end points were symptomatic deep vein thrombosis or pulmonary embolism during and after prophylaxis, asymptomatic venous thrombosis detected by predischarge compression ultrasonography, and major hemorrhage. The duration of follow-up was 84 days. RESULTS: Enoxaparin treatment was started a mean (+/- SD) of 17.9 +/- 10.4 hours after the completion of surgery and was given for a mean of 18.0 +/- 6.9 doses. Eighty-two patients (4.1%; 95% confidence interval, 3.3%-5.0%) developed venous thromboembolism. The rates of thromboembolic events during and after prophylaxis were 2.1% and 2.0%, respectively. Only 3 patients (0.15%) had abnormal predischarge compression ultrasonography. Three patients (0.15%) died of pulmonary embolism. Major hemorrhage occurred in 58 patients (2.9%; 95% confidence interval, 2.2%-3.7%). CONCLUSIONS: Postoperative prophylaxis with enoxaparin for a mean of 9 days is associated with a clinically acceptable rate of symptomatic venous thromboembolism and major hemorrhage. Predischarge compression ultrasonography cannot be justified.

Practical management of venous thromboembolism following pelvic fractures.

The management of thromboembolic complications remains one of the most controversial issues in the care of patients with pelvic and acetabular fractures. Recent studies have indicated that the incidence of proximal deep vein thrombosis is much higher than was previously believed. These patients should be managed with a formal institutional protocol that includes universal prophylaxis, supplemented in some cases by screening for deep vein thrombosis.

A comparison of low-dose heparin with low-molecular-weight heparin as prophylaxis against venous thromboembolism after major trauma.

BACKGROUND: Patients who have had major trauma are at very high risk for venous thromboembolism if they do not receive thromboprophylaxis. We compared low-dose heparin and a low-molecular-weight heparin with regard to efficacy and safety in a randomized clinical trial in patients with trauma. METHODS: Consecutive adult patients admitted to a trauma center who had Injury Severity Scores of at least 9 and no intracranial bleeding were randomly assigned to heparin (5000 units) or enoxaprin (30 mg), each given subcutaneously every 12 hours in a double-blind manner, beginning within 36 hours after the injury. The primary outcome was deep-vein thrombosis as assessed by contrast venography performed on or before day 14 after randomization. RESULTS: Among 344 randomized patients, 136 who received low-dose heparin and 129 who received enoxaparin had venograms adequate for analysis. Sixty patients given heparin (44 percent) and 40 patients given enoxaparin (31 percent) had deep-vein thrombosis (P=0.014). The rates of proximal-vein thrombosis were 15 percent and 6 percent, respectively (P=0.012). The reductions in risk with enoxaparin as compared with heparin were 30 percent (95 percent confidence interval, 4 to 50 percent) for all deep-vein thrombosis and 58 percent (95 percent confidence interval, 12 to 87 percent) for proximal-vein thrombosis. Only six patients (1.7 percent) had major bleeding (one in the heparin group and five in the enoxaparin group, P=0.12). CONCLUSIONS: Low-molecular-weight heparin was more effective than low-dose heparin in preventing venous thromboembolism after major trauma. Both interventions were safe.

Evaluation of an intravenous heparin nomogram in a coronary care unit.

OBJECTIVE: To develop, implement and evaluate an effective and efficient heparin nomogram. DESIGN: Retrospective and prospective data collection. SETTING: Coronary care unit (CCU) of a university-affiliated hospital. PATIENTS: Patients with acute coronary ischemic syndromes requiring intravenous (i.v.) heparin who were not receiving thrombolytic and/or warfarin therapy. INTERVENTIONS: A retrospective chart review of 52 CCU patients receiving iv heparin provided the historical control group. The effectiveness of a heparin nomogram (5000 U bolus followed by an initial weight-based infusion of 15 U/kg/h with subsequent rate adjustments according to activated partial thromboplastin time [aPTT] results) was then prospectively assessed in a further 56 consecutive patients. MAIN RESULTS: The historical control and nomogram groups did not significantly differ with respect to age, weight, duration of therapy or total number of aPTTs drawn. Approximately 79% and 84% of patients in the control and nomogram groups, respectively, achieved an aPTT within the therapeutic range (60 to 90 s, P > 0.05), whereas 89% and 100% of control and nomogram patients, respectively, surpassed the therapeutic threshold (longer than 60 s) at some point during treatment (P = 0.009). Compared with empiric dose adjustment, the nomogram more effectively avoided periods of inadequate anticoagulation. Similarly, the time to achieve the therapeutic threshold was significantly longer in the control than in the nomogram group (8.2 +/- 5.9 versus 6.7 +/- 3.7 h, P = 0.026). No adverse bleeding events were noted in either group. CONCLUSIONS: Compared with conventional approaches, the heparin nomogram successfully achieved and maintained adequate anticoagulation in a greater proportion of patients with acute cardiovascular diseases without the need for additional aPTT measurements.

Thromboembolic complications in patients with pelvic trauma.

Patients with pelvic trauma are known to be at increased risk for the development of thromboembolic complications. The incidence of deep venous thrombosis in patients with pelvic fractures is 35% to 60%. Proximal deep venous thrombosis, which is most likely to result in pulmonary embolism, occurs in 25% to 35% of these patients, and almost 1/2 of all proximal thrombi will be in the pelvic veins. The incidence of symptomatic pulmonary embolism in the pelvic trauma population is 2% to 10% whereas a greater proportion of patients will have clinically silent pulmonary embolism. Fatal pulmonary embolism occurs in 0.5% to 2% of patients with pelvic trauma. The cornerstone of effective management is prophylaxis and the most commonly used forms include low dose heparin, low molecular weight heparin, mechanical devices, and in some studies, inferior vena caval filters. Based on a critical review of the literature, in algorithm is proposed for the management of thromboprophylaxis in this trauma subgroup. This includes prophylaxis, screening, and treatment when proximal thrombosis is identified. Such a systematic approach to this potentially catastrophic problem may decrease the morbidity and mortality associated with thromboembolic complications in these patients.

Prevention of venous thromboembolism after knee arthroplasty. A randomized, double-blind trial comparing enoxaparin with warfarin.

OBJECTIVE: To compare the effectiveness and safety of fixed-dose enoxaparin and adjusted dose warfarin in preventing venous thromboembolism after knee arthroplasty. DESIGN: A randomized, double-blind controlled trial. SETTING: 8 university hospitals. PATIENTS: 670 consecutive patients who had knee arthroplasty. INTERVENTION: Patients were randomly assigned to receive enoxaparin (30 mg subcutaneously every 12 hours) or adjusted-dose warfarin (international normalized ratio, 2.0 to 3.0). Both regimens were started after surgery. MEASUREMENTS: The primary end point was the incidence of deep venous thrombosis in patients with adequate bilateral venograms; the secondary end point was hemorrhage. RESULTS: Among the 417 patients with adequate venograms, 109 of 211 warfarin recipients (51.7%) had deep venous thrombosis compared with 76 of 206 enoxaparin recipients (36.9%) (P = 0.003). The absolute risk difference was 14.8% in favor of enoxaparin (95% Cl, 5.3% to 24.1%) Twenty-two warfarin recipients (10.4%) and 24 enoxaparin recipients (11.7%) had proximal venous thrombosis (P>0.2). The absolute risk difference was 1.2% in favor of warfarin (Cl, -7.2% to 4.8%). The incidence of major bleeding was 1.8% (6 of 334 patients) in the warfarin group and 2.1% (7 of 336 patients) in the enoxaparin group (P>0.2). The absolute risk difference was 0.3% in favor of warfarin (Cl, -2.4% to 1.8%). CONCLUSIONS: A postoperative, fixed-dose enoxaparin regimen is more effective than adjusted-dose warfarin in preventing deep venous thrombosis after knee arthroplasty. No differences were seen in the incidence of proximal venous thrombosis or clinically overt hemorrhage.