Venous thromboembolic prophylaxis: the use of aspirin

Venous thromboembolism (VTE) is a term used collectively for deep vein thrombosis (DVT) and pulmonary embolism. Without prophylaxis, the incidence of documented DVT in the orthopaedic surgery patient is reported in the range of 50%-60%. A multimodal approach to DVT prophylaxis is the standard of care for all patients undergoing total hip arthroplasty and total knee arthroplasty. At our local hospital, low-risk patients are being sent home with aspirin as the medication for VTE prophylaxis. This article will provide an overview of the pathophysiology of VTE and the current prevention guidelines including the use of aspirin.     

Benefits of more aggressive VTE prophylaxis in hospitalized medical patients

Venous thromboembolism (VTE), which includes both deep vein thrombosis and pulmonary embolism, is a well-known risk in surgical patients, but it is also a significant and often unrecognized source of mortality and morbidity in hospitalized medical patients. The need for routine prophylaxis in the general medical population is increasingly supported.     

Venous thromboembolic risk and prevention in acute medical illness

We describe a case in which an elderly woman is hospitalised for acute medical illness and ask how this patient's risk of venous thromboembolism should be assessed and managed. Venous thromboembolism was previously regarded as a surgical problem, but occurs at least as frequently among medical patients. The risk of venous thromboembolism varies, but recent studies have provided detailed data on the risk in patients with acute medical illness, in particular those patients with acute heart failure, respiratory failure and acute infectious disease. As the evidence has accumulated, specific guidelines recommend provision of thromboprophylaxis to patients at risk. An approach to venous thromboembolic risk assessment and prevention in acutely ill medical patients is presented.     

Venous thromboembolism prophylaxis in critically ill patients

Venous thromboembolism (VTE) is a frequent but often silent complication of critical illness that has a negative impact on patient outcomes. The prevention of VTE is an essential component of patient care in the intensive care unit (ICU) setting, and is the focus of this article. The use of anticoagulant thromboprophylaxis significantly decreases the risk of VTE in ICU patients and is discussed at length.     

Venous thromboembolic events in critically ill traumatic brain injury patients

Purpose

To estimate the prevalence, risk factors, prophylactic treatment and impact on mortality for venous thromboembolism (VTE) in patients with moderate to severe traumatic brain injury (TBI) treated in the intensive care unit.

Methods

A post hoc analysis of the erythropoietin in traumatic brain injury (EPO-TBI) trial that included twice-weekly lower limb ultrasound screening. Venous thrombotic events were defined as ultrasound-proven proximal deep venous thrombosis (DVT) or clinically detected pulmonary embolism (PE). Results are reported as events, percentages or medians and interquartile range (IQR). Cox regression analysis was used to calculate adjusted hazard ratios (HR) with 95% confidence intervals (CI) for time to VTE and death.

Results

Of 603 patients, 119 (19.7%) developed VTE, mostly comprising DVT (102 patients, 16.9%) with a smaller number of PE events (24 patients, 4.0%). Median time to DVT diagnosis was 6 days (IQR 2–11) and to PE diagnosis 6.5 days (IQR 2–16.5). Mechanical prophylaxis (MP) was used in 91% of patients on day 1, 97% of patients on day 3 and 98% of patients on day 7. Pharmacological prophylaxis was given in 5% of patients on day 1, 30% of patients on day 3 and 57% of patients on day 7. Factors associated with time to VTE were age (HR per year 1.02, 95% CI 1.01–1.03), patient weight (HR per kg 1.01, 95% CI 1–1.02) and TBI severity according to the International Mission for Prognosis and Analysis of Clinical Trials risk of poor outcome (HR per 10% increase 1.12, 95% CI 1.01–1.25). The development of VTE was not associated with mortality (HR 0.92, 95% CI 0.51–1.65).

Conclusions

Despite mechanical and pharmacological prophylaxis, VTE occurs in one out of every five patients with TBI treated in the ICU. Higher age, greater weight and greater severity of TBI increase the risk. The development of VTE was not associated with excess mortality.

     

Venous thromboembolic disease in the HIV-infected patient

Objective

Infection with the HIV has developed into a chronic illness, with longer-term complications increasingly being seen. There is increasing evidence that infection with HIV may be associated with a hypercoagulable state. This study examines the association of HIV infection with the incidence of both pulmonary embolism and deep venous thrombosis.

Methods

This study was a weighted analysis of data from National Hospital Discharge Survey, a national annual probability survey of discharges from short-stay non-Federal hospitals, from 1996-2004. The risk of pulmonary embolism and/or deep venous thrombosis in an HIV+ individual was ascertained for each age group by calculation of an odds ratio (OR) with a 95% confidence interval (CI). A common OR was computed across strata to evaluate the overall association between PE/DVT and HIV while adjusting for effects of age.

Results

The overall age-adjusted OR indicates a statistically significant increase of 43% for PE in HIV+ individuals as opposed to HIV− individuals (OR, 1.43; 95% CI, 1.39-1.46). This increase differs by age group, with age group 21 to 50 years having the highest odds for PE among HIV+ individuals (OR, 1.58; 95% CI, 1.54-1.63).

Conclusions

The data supports the hypothesis that HIV-infected individuals are more likely to have clinically detected thromboembolic disease as opposed to non-HIV-infected individuals. This study reveals up to a 43% increase in OR of developing a PE, 10% increase in developing a DVT, and 40% increase in developing PE or DVT in an HIV-infected individual over the 9-year study period after adjusting for age.     

Anticoagulant prophylaxis to prevent asymptomatic deep vein thrombosis in hospitalized medical patients: a systematic review and meta-analysis

Summary.  Background:  The effect of anticoagulant prophylaxis on the prevention of deep vein thrombosis (DVT) should include an investigation of both clinical and subclinical DVT. We conducted a systematic review to determine whether anticoagulant prophylaxis reduces the risk of asymptomatic DVT compared to no prophylaxis in at-risk hospitalized medical patients. Methods:  MEDLINE, EMBASE, and the Cochrane Library were searched through March 2007 for randomized trials of anticoagulant prophylaxis for the prevention of asymptomatic DVT, assessed by venogram or ultrasound. We assessed four outcomes: all asymptomatic DVT, asymptomatic proximal DVT, major bleeding and mortality. Random effects meta-analyses were performed and results were expressed using relative risk (RR) and 95% confidence intervals (95% CIs). Results:  Four trials including 5516 patients were eligible. Our pooled analysis demonstrated that compared to placebo, anticoagulant prophylaxis was associated with a significantly lower risk of any asymptomatic DVT (RR 0.51; 95% CI 0.39–0.67) and asymptomatic proximal DVT (RR 0.45; 95% CI 0.31–0.65). Anticoagulant prophylaxis was associated with a significantly increased risk of major bleeding compared to placebo (RR 2.00; 95% CI 1.05–3.79). There was no significant difference in the pooled estimate for all-cause mortality. Anticoagulant prophylaxis conferred an absolute risk reduction of any DVT and proximal DVT of 2.6% and 1.8%, respectively, and was associated with a 0.5% absolute risk increase in major bleeding. Conclusions:  Anticoagulant prophylaxis is effective in preventing asymptomatic DVT in at-risk hospitalized medical patients but is associated with an increased bleeding risk. The therapeutic benefits of anticoagulant prophylaxis appear to outweigh the risks of bleeding.     

Venous thromboembolic disease: an observational study in medical-surgical intensive care unit patients

Purpose: Acute and chronic illness, immobility, and procedural and pharmacologic interventions may predispose patients in the intensive care unit (ICU) to venous thromboembolic (VTE) disease. The purpose of this study was to observe potential risk factors and diagnostic tests for VTE, and prophylaxis against VTE in medical-surgical ICU patients. Materials and Methods: In a prospective observational study, 93 consecutive patients admitted to a mixed medical-surgical ICU were followed. We recorded demographics, admitting diagnoses, APACHE II score, VTE risk factors, antithrombotic, anticoagulant and thrombolytic agents, diagnostic tests for deep venous thrombosis (DVT) and pulmonary embolus (PE), and clinical outcomes. Results: Patients were 65.5 (15.5) years old with an APACHE II score of 21.1 (9.0); 44 (47.3%) were female. Admission diagnoses were medical (58, 67.4%) and surgical (35, 37.6%). The duration of ICU stay was 3 days (interquartile range: 1, 8.5 days) and the ICU mortality rate was 20.4% (19 of 93). We observed 8 VTE events among 5 of 93 patients (incidence 5.4% [0.8 to 10.0]); 2 patients had DVT and PE before admission, 1 had DVT as an admitting diagnosis, 1 had DVT on day 2 and PE on day 3, and 1 had PE on day 2. Over 804 ICU patient-days, 2 of 5 ultrasound examinations diagnosed DVT and 2 of 3 ventilation-perfusion lung scans diagnosed PE. Of 64 patients in whom heparin was not contraindicated and who were not anticoagulated, subcutaneous heparin prophylaxis was prescribed for 40 (62.5%) patients. ICU-acquired VTE risk factors were mechanical ventilation (odds ratio [OR] 1.56), immobility (OR 2.14), femoral venous catheter (OR 2.24), sedatives (OR 1.52), and paralytic drugs (OR 4.81), whereas VTE heparin prophylaxis (OR 0.08), aspirin (OR 0.42), and thromboembolic disease stockings (OR 0.63) were associated with a lower risk. Only warfarin (OR 0.07, P = .01) and intravenous heparin (OR 0.04, P < .01) were associated with a significantly decreased risk of VTE. Conclusions: Several ICU-acquired risk factors for VTE were documented in this medical-surgical ICU. VTE prophylaxis was underprescribed, and VTE diagnostic tests were infrequent. Further research is required to determine the incidence, predisposing factors, attributable morbidity, mortality, and costs of VTE in medical-surgical ICU patients, the optimal diagnostic test strategies, and the most cost-effective approaches of prophylaxis. Copyright © 2000 by W.B. Saunders Company     

Venous thromboembolic disease and hematologic considerations in obesity

Venous thromboembolic disease continues to be a major source of morbidity and mortality, with obese patients who are critically ill presenting some of the most at-risk patients. As the literature evolves, it has become clear that there is a complex relationship between obesity and thrombosis and atherogenesis. It is true that many of these conditions are reversible with weight loss; however, obesity remains on the rise. Management of obese patients must incorporate and consider these intricate changes in an attempt to improve patient outcomes.     

内科住院患者静脉血栓栓塞症的预防

现已明确,对有静脉血栓栓塞症（VTE）高危风险的内科住院患者给予血栓预防措施可明确降低VTE的发病率和病死率。2009年我国颁布了＂内科住院患者静脉血栓栓塞症预防的中国专家建议＂〔1〕。2012年美国胸科医师学会颁布了血栓形成抗栓治疗和预防第9版指南〔2〕,此文对该指南中有关内科住院患者VTE预防的建议进行解读。     

Clinical predictors of prophylaxis use prior to the onset of acute venous thromboembolism in hospitalized patients SWIss Venous ThromboEmbolism Registry (SWIVTER)

Summary. Background: We investigated clinical predictors of appropriate prophylaxis prior to the onset of venous thromboembolism (VTE). Methods: In 14 Swiss hospitals, 567 consecutive patients (306 medical, 261 surgical) with acute VTE and hospitalization < 30 days prior to the VTE event were enrolled. Results: Prophylaxis was used in 329 (58%) patients within 30 days prior to the VTE event. Among the medical patients, 146 (48%) received prophylaxis, and among the surgical patients, 183 (70%) received prophylaxis (P < 0.001). The indication for prophylaxis was present in 262 (86%) medical patients and in 217 (83%) surgical patients. Among the patients with an indication for prophylaxis, 135 (52%) of the medical patients and 165 (76%) of the surgical patients received prophylaxis (P < 0.001). Admission to the intensive care unit [odds ratio (OR) 3.28, 95% confidence interval (CI) 1.94–5.57], recent surgery (OR 2.28, 95% CI  1.51–3.44), bed rest > 3 days (OR 2.12, 95% CI  1.45–3.09), obesity (OR 2.01, 95% CI  1.03–3.90), prior deep vein thrombosis (OR 1.71, 95% CI  1.31–2.24) and prior pulmonary embolism (OR 1.54, 95% CI  1.05–2.26) were independent predictors of prophylaxis. In contrast, cancer (OR 1.06, 95% CI  0.89–1.25), age (OR 0.99, 95% CI  0.98–1.01), acute heart failure (OR 1.13, 95% CI  0.79–1.63) and acute respiratory failure (OR 1.19, 95% CI  0.89–1.59) were not predictive of prophylaxis. Conclusions: Although an indication for prophylaxis was present in most patients who suffered acute VTE, almost half did not receive any form of prophylaxis. Future efforts should focus on the improvement of prophylaxis for hospitalized patients, particularly in patients with cancer, acute heart or respiratory failure, and in the elderly.     

The underutilization of venous thromboembolism prophylaxis in medical patients

Venous thromboembolism (VTE), long been recognized as a preventable complication of hospitalization, is becoming more widely recognized as a risk for both medical and surgical patients. Recommendations exist for VTE prophylaxis (PPX) in medical patients, but current research shows that the utilization of these guidelines is suboptimal. The rates of VTE PPX are lower than recommended rates, and in those patients receiving PPX, the type, dosage, or duration is not in accordance with recognized recommendations. The recommendations and protocols for medical patients that are currently available should be followed, and as new research is developed and reviewed, current practice should be changed to reflect it. The clinical nurse specialist is in a unique position to assimilate the current recommendations into practice and to enhance patient care by virtue of having multiple spheres of influence, capable of influencing institution policy, patient, family, nurse, and physician education, and direct patient care. The VTE PPX is not overused, but underused, and institutions, physicians, and nurses all need to be cognizant of patient risk for VTE with the need to treat prophylactically and initiate PPX according to the American College of Chest Physicians guidelines.