Epidemiology and Incidence: The Scope of the Problem and Risk Factors for Development of Venous Thromboembolism

Intermediate-Risk and High-Risk Pulmonary Embolism: Recognition and Management: Cardiology Clinics: Cardiac Emergencies

Pulmonary embolism (PE) is the third most common cause of cardiovascular death. Every specialty of medical practitioner will encounter PE in their patients, and should be prepared to employ contemporary strategies for diagnosis and initial risk-stratification. Treatment of PE is based on risk-stratification, with anticoagulation for all patients, and advanced modalities including systemic thrombolysis, catheter-directed therapies, and mechanical circulatory supports utilized in a manner paralleling PE severity and clinical context.

Diagnosis of Pulmonary Embolism in Pregnancy

Pulmonary embolism (PE) is a significant cause of obstetric morbidity and mortality. However, overdiagnosis related to excessive use of diagnostic testing is also associated with long-term major health issues, including impact on future pregnancies and subsequent health care. Accurate diagnosis of PE depends on the knowledge of prevalence of PE in the pregnant population, the a priori probability of a PE based on specific findings in a given patient, and understanding of the accuracy of computed tomography pulmonary angiography (CTPA), the dominant diagnostic modality employed for this diagnosis. Venous thromboembolism is widely considered to be more common in pregnancy. However, this term includes both deep venous thrombosis as well as PE. While the former appears to be more common, published data on the prevalence of PE in pregnancy show little or no increase relative to the general population. Given the published data on the sensitivity and specificity of CTPA, a positive reading is more likely to be a false positive unless the probability of a PE in a given patient is at least 5% (a 200-fold increase from baseline). Doubling the probability to 10% (a 400-fold increase) only improves the positive predictive value to approximately 67%. Strategies to refine the a priori probability of a PE in a given patient are detailed, including scoring systems and D-dimer measurements. A careful history and physical examination and thoughtful development of a differential diagnosis are key elements of clinical practice and should include both the likelihood of each possible diagnosis and the accuracy of diagnostic modalities. This approach should precede the application of a given algorithm. Such a structured approach can decrease utilization and limit false positive diagnoses without increasing morbidity or mortality. KEY POINTS: · Incidence of PE is lower than assumed.. · Incidence is critical for assessing predictive value of a test.. · Computed tomography angiography is likely overused in pregnancy.. · Clinical scoring and D-dimer have a role in PE diagnosis..

Massive Pulmonary Embolism Related to a Patient With Heart Failure Secondary to Stress Cardiomyopathy: A Case Report

Venous thromboembolism (VTE) is a common disease, which includes deep venous thrombosis (DVT) and pulmonary embolism (PE). It is the third most common cardiovascular disorder, affecting predominantly the male elderly population. Stress cardiomyopathy (SC) is a transitorily cardiovascular condition produced after an emotional or physical trigger, and it features signs and symptoms of acute coronary syndrome. Its pathophysiological mechanisms remain unclear, and SC has also been related to critical complications such as heart failure, arrhythmias, left ventricular outflow obstruction, and thromboembolic events. This case report highlights the association of PE and SC that might play a pathophysiological role.

Elderly hip fracture patients with isolated calf muscle vein thrombosis are more likely to have suffered an intertrochanteric fracture and be hypertensive

PURPOSE

This study aimed to characterize the preoperative deep venous thrombosis (DVT) of lower extremity by locations and evaluate the diagnostic ability of plasma D-dimer level in elderly patients with hip fracture.

METHOD

This retrospective study reviewed the elderly patients presenting with a hip fracture definitely undergoing surgical treatment and identified those who had preoperative DVT. Data on demographics, lifestyle habits, comorbidities and laboratory indexes were extracted and collected. Four groups were divided by presence and locations of thrombi: non-DVT (controls), isolated calf muscle vein thrombosis (CMVT), deep calf vein thrombosis (DCVT) and proximal DVT group. The comparisons were conducted between either DVT group or the non-DVT group. Receiver operating characteristic (ROC) curve and the area under the curve (AUC) were used for determining the diagnostic ability of D-dimer for each group.

RESULTS

Among 951 eligible patients included, 298 (31.3%) were found have preoperative DVT. Compared to non-DVT group, patients with CMVT had significantly lower albumin and hemoglobin concentration, more likely an intertrochanteric fracture and a higher prevalence of hypertension (P = 0.001, 0.006, 0.002 and 0.024, respectively); DCVT group was not observed to be significantly different in terms of any variables (all P > 0.05); and proximal DVT group had older age and more patients ≥ 80 years, lower albumin and hemoglobin concentration, higher prevalence of hypertension, more likely an intertrochanteric fracture, extended time from injury to imaging examination and higher age-adjusted Charlson comorbidity index (ACCI) (all P < 0.05). D-dimer demonstrated nonsignificant diagnostic ability for CMVT and DCVT, and a significant but poor ability for proximal DVT (AUC, 0.621; 95% CI 0.542-0.710; P = 0.011).

CONCLUSION

Varying characteristics were found among preoperative DVT stratified by locations after elderly hip fractures, and D-dimer level demonstrated no or poor diagnostic ability for DVTs by locations. Level of evidence level III, diagnostic. Trial registration statement Not applicable.

The association between cancer diagnosis, care, and outcomes in 1 million patients hospitalized for acute pulmonary embolism

OBJECTIVES

To evaluate the clinical care provided to cancer patients hospitalized for acute pulmonary embolism (PE), as well as the association between type of cancer, in-hospital care, and clinical outcomes.

METHODS

This study examined the in-hospital care (systemic thrombolysis, catheter-directed thrombolysis, and surgical thrombectomy/embolectomy) and clinical outcomes (mortality, major bleeding, and hemorrhagic stroke) among adults hospitalized due to acute PE between October 2015 to December 2018 using the National Inpatient Sample (NIS). Multivariable logistic regression analysis was used to determine adjusted odds ratios (aOR) with 95% confidence interval (95% CI).

RESULTS

Of 1,090,130 hospital records included in the analysis, 216,825 (19.9%) had current cancer diagnoses, including lung (4.7%), hematological (2.5%), colorectal (1.6%), breast (1.3%), prostate (0.8%), and 'other' cancer (9.0%). Cancer patients had lower adjusted odds of receiving systemic thrombolysis, catheter-directed therapy, and surgical thrombectomy/embolectomy compared with their non-cancer counterparts (P < 0.001), except for systemic thrombolysis (aOR 0.96, 95% CI 0.85-1.09, P = 0.553) and catheter-directed therapy (aOR 0.82, 95% CI 0.67-1.00, P = 0.053) for prostate cancer. Cancer patients had greater odds of mortality (P < 0.05). Lung cancer patients had the highest odds of mortality (aOR 2.68, 95% CI 2.61-2.76, P < 0.001) and hemorrhagic stroke (aOR 1.75, 95% CI 1.61-1.90, P < 0.001), while colorectal cancer patients had the greatest odds of bleeding (aOR 2.04, 95% CI 1.94-2.15, P < 0.001).

CONCLUSION

Among those hospitalized for PE, cancer diagnoses were associated with lower odds of invasive management and poorer in-hospital outcomes, with metastatic status being an especially important determinant. Appropriateness of care could not be assessed in this study.

Rapid progressive vaccine-induced immune thrombotic thrombocytopenia with cerebral venous thrombosis after ChAdOx1 nCoV-19 (AZD1222) vaccination: A case report

BACKGROUND

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare and potentially life-threatening condition after receiving coronavirus disease vaccines. It is characterized by symptom onset at 5 to 30 d postvaccination, thrombocytopenia, thrombosis, high D-dimer level, and antiplatelet factor 4 (anti-PF4) antibody positivity. VITT can progress very fast, requiring urgent management. Only few studies have described its detailed clinical course and imaging changes. We report a typical VITT case in a patient who underwent regular repeated brain imaging examinations.

CASE SUMMARY

A young woman presented with headaches at 7 d after the ChAdOx1 nCoV-19 vaccine (AZD1222) injection. She then showed progressive symptoms of left upper limb clumsiness. Brain computed tomography revealed venous infarction at the right parietal lobe with a hyperacute thrombus in the cortical vein. Two hours later, brain magnetic resonance imaging revealed hemorrhage at the same area. Magnetic resonance venography showed an irregular contour of the right transverse sinus. Laboratory examination revealed a high D-dimer level, thrombocytopenia, and a high titer for anti-PF4 antibodies. She was treated with anticoagulants, intravenous immunoglobulin, and steroids and analgesic agents were administered for pain control. She had a marked improvement on headaches and clumsiness after treatment along with radiological thrombus resolution. During follow-up at the outpatient department, her modified Rankin scale at 90 d was 1.

CONCLUSION

Clinicians should be alerted whenever patients present with persistent and progressive headaches or focal motor/sensory deficits postvaccination.

The Impact of Obesity on Plastic Surgery Outcomes: A Systematic Review and Meta-analysis

BACKGROUND

Obesity is a potential risk factor for complications in plastic surgeries. However, the data presented by primary studies are contradictory.

OBJECTIVES

The aim of this study was to summarize and clarify the divergences in the literature to provide a better understanding of the impact of obesity in different plastic surgery procedures.

METHODS

We conducted a systematic review and meta-analysis of the impact of obesity on plastic surgery outcomes. Searches were conducted in MEDLINE, LILACS, SciELO, Scopus, Embase, Web of Science, Opengrey.eu, and the Cochrane Database of Systematic Reviews. The primary outcomes assessed were surgical complications, medical complications, and reoperation rates. The secondary outcome assessed was patient satisfaction. Subgroup analysis was performed to investigate the impact of each BMI category on the outcomes.

RESULTS

Ninety-three articles were included in the qualitative synthesis, and 91 were used in the meta-analysis. Obese participants were 1.62 times more likely to present any of the primary outcomes (95% CI, 1.48-1.77; P < 0.00001). The highest increase in risk among plastic surgery types was observed in cosmetic procedures (risk ratio [RR], 1.80; 95% CI, 1.43-2.32; P < 0.00001). Compared with normal-weight participants, overweight participants presented a significantly increased RR for complications (RR, 1.16; 95% CI, 1.07-1.27; P = 0.0004). Most authors found no relation between BMI and overall patient satisfaction.

CONCLUSIONS

Obesity leads to more complications and greater incidence of reoperation compared with nonobese patients undergoing plastic surgeries. However, this effect is not evident in reconstructive surgeries in areas of the body other than the breast.

Acute Saddle Embolus With Thrombus in Transit: A Case Report and Review of the Literature

Pulmonary embolism is a life-threatening medical emergency associated with right ventricular failure. Rarely, it impacts the left ventricle to the point of compromising the left ventricular (LV) ejection fraction. We present a case of a 73-year-old African American male with a medical history pertinent for intravascular large B-cell lymphoma who developed an acute saddle embolus with a “clot-in-transit” and profound LV systolic dysfunction. Our report illustrates how an acute saddle embolus may be associated with LV systolic dysfunction via the “reverse Bernheim effect.” Additionally, the report highlights the significance of a “clot-in-transit” and LV systolic dysfunction, as they both directly correlate with increased risk of mortality.

Incidence of pulmonary embolism and impact on mortality in patients with malignant melanoma

PURPOSE

Pulmonary embolism (PE) occurs frequently in patients with malignant melanoma (MM). The aim of this study is to determine the incidence of PE in patients with MM and to assess the clinical characteristics and mortality of MM patients with PE.

MATERIAL AND METHODS

Medical records from 381 MM patients who underwent contrast-enhanced computed tomography were evaluated. Imaging parameters including location of PE and measurements of right heart dysfunction and clinical parameters including D-Dimer levels, local and distant tumor stage and time of death were analyzed.

RESULTS

PE was found in 23/381 (6%) MM patients, whereby 17/23 (74%) were detected incidentally and only 6/23 (26%) were symptomatic. The presence of PE significantly correlated with elevated D-Dimers (p < 0.001), right ventricular dysfunction (p = 0.04), higher local tumor stage (≥T3) (p = 0.05), presence of visceral (p = 0.02) or cerebral metastases (p = 0.03) and increased mortality (p = 0.05). Further, patients with central PE showed an increased mortality compared to peripheral PE (p = 0.03), but no correlation was found between the localization of PE and the occurrence of clinical symptoms (p = 0.36).

CONCLUSION

PE in patients with MM often occurs without clinical symptoms and is indicative for advanced disease and a poorer prognosis.

Machine learning with D-dimer in the risk stratification for pulmonary embolism: a derivation and internal validation study

AIM

To develop a machine learning model to predict the diagnosis of pulmonary embolism (PE).

METHODS AND RESULTS

We undertook a derivation and internal validation study to develop a risk prediction model for use in patients being investigated for possible PE. The machine learning technique, generalized logistic regression using elastic net, was chosen following an assessment of seven machine learning techniques and on the basis that it optimized the area under the receiver operator characteristic curve (AUC) and Brier score. Models were developed both with and without the addition of D-dimer. A total of 3347 patients were included in the study of whom, 219 (6.5%) had PE. Four clinical variables (O2 saturation, previous deep venous thrombosis or PE, immobilization or surgery, and alternative diagnosis equal or more likely than PE) plus D-dimer contributed to the machine learning models. The addition of D-dimer improved the AUC by 0.16 (95% confidence interval 0.13-0.19), from 0.73 to 0.89 (0.87-0.91) and decreased the Brier score by 14% (10-18%). More could be ruled out with a higher positive likelihood ratio than by the Wells score combined with D-dimer, revised Geneva score combined with D-dimer, or the Pulmonary Embolism Rule-out Criteria score. Machine learning with D-dimer maintained a low-false-negative rate at a true-negative rate of nearly 53%, which was better performance than any of the other alternatives.

CONCLUSION

A machine learning model outperformed traditional risk scores for the risk stratification of PE in the emergency department. However, external validation is needed.

Practical Utility of D-dimer Test for Venous Thromboembolism in Systemic Lupus Erythematosus Depends on Disease Activity: a Retrospective Cohort Study

BACKGROUND

The D-dimer test is a screening tool for venous thromboembolism (VTE); however, its utility for patients with systemic lupus erythematosus (SLE) remains unclear. Here, we examined the utility of the D-dimer test as a screening tool for VTE in SLE patients.

METHODS

SLE patients (n = 276) and age- and sex-matched patients with non-rheumatic disease (n = 1,104), all of whom underwent D-dimer testing to screen for VTE, were enrolled. The sensitivity and specificity and receiver operating characteristics curve of the D-dimer test were compared in both groups. Then, subgroup of SLE patients in whom the D-dimer test can be useful was sought.

RESULTS

The incidence of VTE was more common in SLE patients than controls (10.9% vs. 4.0%). Although the sensitivity of the D-dimer test was comparable between SLE patients and controls (93.3% vs. 90.9%), the specificity of the test was profoundly lower in SLE patients compared to controls (28.4% vs. 84.4%). The area under the curve (AUC) of the D-dimer for VTE was 0.669 in SLE patients and 0.90 in control group. Multiple linear regression analysis demonstrated that SLE disease activity index-2000 (SLEDAI-2K) was significantly associated with D-dimer levels in SLE patients (β = 0.155; P = 0.022). Subgroup analysis showed that the AUC is moderate (0.768) with low disease activity, while it is low (0.518) with high SLEDAI-2K.

CONCLUSION

The D-dimer test may not be a useful screening tool for VTE in patients with active SLE. D-dimer test for predicting VTE in SLE patients should be differentially applied according to disease activity of SLE.

Disseminating a patient-centered education bundle to reduce missed doses of pharmacologic venous thromboembolism (VTE) prophylaxis to a community hospital

Background

Venous thromboembolism (VTE) is a leading cause of preventable harm in hospitalized patients. However, many doses of prescribed pharmacologic VTE prophylaxis are frequently missed. We investigated the effect of a patient-centered education bundle on missed doses of VTE prophylaxis in a community hospital.

Methods

We performed a pre-post analysis examining missed doses of VTE prophylaxis in a community hospital. A real-time alert from the electronic health record system facilitated the delivery of a patient education bundle intervention. We included all patient visits on a single floor where at least 1 dose of VTE prophylaxis was prescribed during pre- (January 1, 2018, - November 31, 2018) and post- (January 1 - June 31, 2019) intervention periods. Outcomes included any missed dose (primary) and reasons for missed doses (refusal, other [secondary]) and were compared between both periods.

Results

1,614 patient visits were included. The proportion of any missed dose significantly decreased (13.8% vs. 8.2% [OR, 0.56; 95% CI, 0.48, 0.64]) between the pre-post intervention periods. Patient refusal was the most frequent reason for missed doses. In the post-intervention period, patient refusal significantly decreased from 8.8% to 5.0% (OR, 0.54; 95% CI, 0.46, 0.64). Similarly, other reasons for missed doses significantly decreased from 5.0% to 3.2% (OR, 0.62; 95% CI, 0.51, 0.77).

Conclusions

A real-time alert-triggered patient-centered education bundle developed and tested in an academic hospital, significantly reduced missed doses of prescribed pharmacologic VTE prophylaxis when disseminated to a community hospital.

Pulmonary embolism: update on management and controversies

Pulmonary embolism is a common and potentially fatal cardiovascular disorder that must be promptly diagnosed and treated. The diagnosis, risk assessment, and management of pulmonary embolism have evolved with a better understanding of efficient use of diagnostic and therapeutic options. The use of either clinical probability adjusted or age adjusted D-dimer interpretation has led to a reduction in diagnostic imaging to exclude pulmonary embolism. Direct oral anticoagulation therapies are safe, effective, and convenient treatments for most patients with acute venous thromboembolism, with a lower risk of bleeding than vitamin K antagonists. These oral therapeutic options have opened up opportunities for safe outpatient management of pulmonary embolism in selected patients. Recent clinical trials exploring the use of systemic thrombolysis in intermediate to high risk pulmonary embolism suggest that this therapy should be reserved for patients with evidence of hemodynamic compromise. The role of low dose systemic or catheter directed thrombolysis in other patient subgroups is uncertain. After a diagnosis of pulmonary embolism, all patients should be assessed for risk of recurrent venous thromboembolism to guide duration of anticoagulation. Patients with a venous thromboembolism associated with a strong, transient, provoking risk factor can safely discontinue anticoagulation after three months of treatment. Patients with an ongoing strong risk factor, such as cancer, or unprovoked events are at increased risk of recurrent events and should be considered for extended treatment. The use of a risk prediction score can help to identify patients with unprovoked venous thromboembolism who can benefit from extended duration therapy. Despite major advances in the management of pulmonary embolism, up to half of patients report chronic functional limitations. Such patients should be screened for chronic thromboembolic pulmonary hypertension, but only a small proportion will have this as the explanation of their symptoms. In the remaining patients, future studies are needed to understand the pathophysiology and explore interventions to improve quality of life.

Lower risk of venous thromboembolism in multiple Asian ethnic groups

Lower risk of venous thromboembolism in Asians compared to Whites has been suggested. Despite the biological and cultural diversity of Asian Americans, data are sparse for specific ethnic groups.

In our prior study of lower Asian American risk, the small number of subjects (337 in all races) precluded accurate study of specific Asian American groups. We present here a new study with 4674 venous thromboembolism subjects diagnosed between 1996 and 2015. Our study population was derived from 61,459 voluntary health examinees in a comprehensive northern California health plan with self-classified ethnicity: 53.0% Whites, 28.4% Blacks, 11.6% ASAMs, 6.8% Others. Of Asian Americans, 44.7% were Chinese, 32.8% Filipinos, 12.9% Japanese, 4.5% South Asians, and 5.0% Other Asians.

Chinese, Japanese, Filipinos, and Other Asians each had lower venous thromboembolism risk than both Whites and South Asians, who had risk similar to each other. These data indirectly support a genetic explanation.

Contraceptive care for Canadian youth

Sexual and reproductive health is an important component of comprehensive health care for youth. This statement provides guidance for selecting and prescribing contraceptives for youth, including commonly prescribed hormonal contraceptives-the pill, patch, ring and injectable progestin-and long-acting reversible contraceptives (LARCs). LARCs, including subdermal implants (which are not available in Canada) and intrauterine contraceptives (IUCs), are substantially more effective during typical use than hormonal contraceptives. This statement endorses LARCs as the first-line option for contraception for Canadian youth, while emphasizing that providers must collaborate with youth to select a contraceptive method that is acceptable, safe, effective and practical for them. Strategies that eliminate obstacles to initiating and continuing contraception are provided.

Guidelines' risk assessment recommendations for venous thromboembolism prophylaxis: A comparison and implementability appraisal

INTRODUCTION

Venous thromboembolism (VTE) prophylaxis guidelines for non-surgical patients recommend VTE- and bleeding risk assessment to guide prophylactic strategies. These recommendations differ between guidelines and implementation is suboptimal. Assessing a guideline's implementability characteristics helps predicting the ease of implementation and reveals barriers.

OBJECTIVES

We aimed to compare guidelines' risk assessment recommendations and critically appraise the implementability characteristics.

MATERIAL AND METHODS

Two guidelines, one from the American College of Chest Physicians and one from the National Institute for Health and Care Excellence were selected for comparison. Risk assessment methods and subsequent prophylactic recommendations were compared. Eight experts then appraised the guideline recommendations on intrinsic implementability characteristics using the GuideLine Implementability Appraisal (GLIA) instrument. GLIA identifies barriers and facilitators for guideline implementation in nine dimensions.

RESULTS

Eleven out of 20 individual VTE-risk factors and 2 out of 19 individual bleeding-risk factors used, were present in both guidelines. Additionally, a high VTE- or bleeding risk was defined differently between the two guidelines. The GLIA appraisal identified implementation barriers within all recommendations analyzed. On content level, barriers were identified in recommendations addressing bleeding risk assessment, mechanical prophylaxis and critical care patients. On implementability level, barriers were identified in decidability, flexibility, effect on process of care and computability dimensions.

CONCLUSION

Depending on the guideline used, VTE-prophylaxis will most likely be provided to different non-surgical patient populations, primarily due to discordance in bleeding risk assessment. Revising the recommendations, taking into account the most apparent implementation barriers, should be considered. However, insufficient evidence to support the recommendations currently complicates this.

Venous thromboembolism among pediatric orthopedic trauma patients: a database analysis

Using the 2012 Kids Inpatient Database, we assessed records of pediatric patients (<21 years old) with fractures of the upper limb, lower limb, spine, pelvis, and multiple locations and calculated the overall prevalence of venous thromboembolism (VTE) and associated potential risk factors. 387 (0.68%) of 57 183 patients with one or more fractures were diagnosed with VTE. Children sustaining fractures of the axial skeleton and those with multiple fractures had a higher prevalence of VTE than those with isolated extremity fractures. Associated risk factors included the presence of a central venous catheter. A prospective, multicenter study is needed to confirm our findings.

ERAS: Safety checklists, antibiotics, and VTE prophylaxis

The concept rested on several components that many of us have now tried to adopt or improve on, inclusive of a multidisciplinary team, a multimodal approach to anesthesia and preoperative preparedness, evidence-based approach to care protocols; and a change in management using interactive and continuous audit prior to and post-procedure. This article describes the development of ERAS protocols relative to checklist implementation, antibiotic use, and venous thromboembolism (VTE) prevention, how these ideas are developed and operationalized as well as how they are evolving and spreading across the care continuum to achieve sustained outcome improvements.

Prescriber knowledge and attitudes regarding non-administration of prescribed pharmacologic venous thromboembolism prophylaxis

Pharmacologic venous thromboembolism (VTE) prophylaxis is important patient safety practice in hospitalized patients. However, a substantial number of ordered doses are not administered. Patient and nursing attitudes and behaviors can influence whether a patient receives a dose. The objective of this single center study was to evaluate prescriber knowledge and attitudes regarding missed doses of pharmacologic VTE prophylaxis. An anonymous, 9-question survey was administered to internal medicine and general surgery resident physicians. The survey captured prescriber opinions on issues related to non-administration of VTE prophylaxis. Thirty-two percent of medicine residents compared with 3 % of surgery residents felt pharmacologic VTE prophylaxis was not necessary in an independently ambulating patient (P < 0.001). Medicine residents were more likely to agree that it is appropriate for nurses to make clinical decisions to determine whether a dose of pharmacologic VTE prophylaxis should be administered to a patient (24 vs. 0 %, P < 0.001). Study findings indicate the need for additional resident physician education. Further investigation is needed to assess these beliefs and ensure patients receive necessary VTE prophylaxis.

Admission rates for emergency department patients with venous thromboembolism and estimation of the proportion of low risk pulmonary embolism patients: a US perspective

Objective

Introduction of target specific anticoagulants and recent guidelines encourage outpatient management of low risk patients with venous thromboembolism. We describe hospital admission rates over time for patients presenting to US emergency departments (EDs) with deep vein thrombosis (DVT) and pulmonary embolism (PE) and estimate the proportion of low-risk PE patients who could potentially be managed as outpatients.

Methods

We performed a structured analysis of the National Hospital Ambulatory Medical Care Survey (a nationally representative weighted sampling of US ED visits) database for the years 2006–2010 including all adult patients with a primary diagnosis of DVT or PE. Simplified pulmonary embolus scoring index (sPESI) scores were determined in patients with PE to identify low risk patients.

Results

There were an estimated 652,000 and 394,000 ED visits for DVT and PE over the 5-year period (0.17%). Mean (SE) age was 59 (1.3), 50% were female, and 40% were > 65 years. Admission rates for DVT and PE were 52% and 90% respectively with no significant changes over time. In patients with DVT, predictors for admission were age (odds ratio, 1.03 per year of age [95% confidence interval, 1.01 to 1.05]) and race (odds ratio, 4.1 [95% confidence interval, 0.9 to 19.8] for Hispanics and 2.9 [1.2 to 7.4] for Blacks). Of all ED patients with PE, 51% were low risk based on sPESI scores.

Conclusion

Admission rates for DVT and PE have remained high and unchanged, especially with PE, minorities, and in older patients. Based on sPESI scores, up to half of PE patients might be eligible for early discharge or outpatient therapy.

Analysis of Risk Factors for Lower-limb Deep Venous Thrombosis in Old Patients after Knee Arthroplasty

Background:

Deep venous thrombosis (DVT) is a common complication of arthroplasty in old patients. We analyzed risk factors for lower-limb DVT after arthroplasty in patients aged over 70 years to determine controllable risk factors.

Methods:

This was a retrospective study of 1,025 patients aged >70 years treated with knee arthroplasty at our hospital between January 2009 and December 2013. Of 1,025 patients, 175 had postoperative lower-limb DVT. We compared medical history, body mass index (BMI), ambulatory blood pressure, preoperative and postoperative fasting blood glucose (FBG), preoperative blood total cholesterol, triglyceride, high- and low-density lipoprotein cholesterol, and preoperative homocysteine (Hcy) between thrombus and non-thrombus groups. B-mode ultrasonography was used to detect lower-limb DVT before the operation and 7 days after the operation in all patients. Logistic regression analysis was used to determine risk factors for DVT.

Results:

Incidence of diabetes (P = 0.014), BMI (P = 0.003), preoperative FBG (P = 0.004), postoperative FBG (P = 0.012), and preoperative Hcy (P < 0.001) were significantly higher in the thrombus group. A significantly greater proportion of patients in the non-thrombus group had early postoperative activity (P < 0.001) and used a foot pump (P < 0.001). Operative duration was significantly longer in the thrombus group (P = 0.012). Within the thrombus group, significantly more patients had bilateral than unilateral knee arthroplasty (P < 0.01). Multivariate logistic analysis revealed BMI, preoperative Hcy, postoperative FBG, long operative duration, bilateral knee arthroplasty, and time to the activity after the operation to be predictive factors of DVT. At 6-month follow-up of the thrombus group, 4.7% of patients had pulmonary embolism and 18.8% had recurrent DVT; there were no deaths.

Conclusions:

Obesity, inactivity after operation, elevated preoperative Hcy and postoperative FBG, long operative duration, and bilateral knee arthroplasty were risk factors for DVT in patients aged over 70 years.

Validation of the International Medical Prevention Registry on Venous Thromboembolism Bleeding Risk Score

BACKGROUND

Recent guidelines recommend assessing medical inpatients for bleeding risk prior to providing chemical prophylaxis for VTE. The International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) bleeding risk score (BRS) was derived from a well-defined population of medical inpatients but it has not been validated externally. We sought to externally validate the IMPROVE BRS.

METHODS

We prospectively collected characteristics on admission and VTE prophylaxis data each hospital day for all patients admitted for a medical illness to the Walter Reed Army Medical Center over an 18-month period. We calculated the IMPROVE BRS for each patient using admission data and reviewed medical records to identify bleeding events.

RESULTS

From September 2009 through March 2011, 1,668 inpatients met the IMPROVE inclusion criteria. Bleeding events occurred during 45 separate admissions (2.7%); 31 events (1.9%) were major and 14 (0.8%) were nonmajor but clinically relevant. Two hundred fifty-six patients (20.7%) had an IMPROVE BRS ≥ 7.0. Kaplan-Meier curves showed a higher cumulative incidence of major (P = .02) and clinically important (major plus clinically relevant nonmajor) (P = .06) bleeding within 14 days in patients with an IMPROVE BRS ≥ 7.0. An IMPROVE BRS ≥ 7.0 was associated with major bleeding in Cox-regression analysis adjusted for administration of chemical prophylaxis (OR, 2.6; 95% CI, 1.1-5.9; P = .03); there was a trend toward a significant association with clinically important bleeding (OR, 1.9; 95% CI, 0.9-3.7; P = .07).

CONCLUSIONS

The IMPROVE BRS calculated at admission predicts major bleeding in medical inpatients. This model may help assess the relative risks of bleeding and VTE before chemoprophylaxis is administered.

Risk of venous thromboembolism among hospitalizations of adults with selected autoimmune diseases

Previous research has suggested autoimmune diseases are risk factors for developing venous thromboembolism (VTE). We assessed whether having diagnoses of selected autoimmune diseases associated with antiphospholipid antibodies--autoimmune hemolytic anemia (AIHA), immune thrombocytopenic purpura (ITP), rheumatoid arthritis (RA), and systemic lupus erythematosus (SLE)--were associated with having a VTE diagnosis among US adult hospitalizations. A cross-sectional study was conducted using the 2010 Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality. VTE and autoimmune diseases were identified using International Classification of Diseases, Ninth Revision, Clinical Modification coded diagnoses information. The percentages of hospitalizations with a VTE diagnosis among all non-maternal adult hospitalizations without any of the four autoimmune diseases of interest and among those with AIHA, ITP, RA, and SLE diagnoses were 2.28, 4.46, 3.35, 2.65 and 2.77%, respectively. The adjusted odds ratios (OR) for having a diagnosis of VTE among non-maternal adult hospitalizations with diagnoses of AIHA, ITP, RA, and SLE were 1.25 [95% confidence interval (CI) 1.05-1.49], 1.20 (95% CI 1.07-1.34), 1.17 (95% CI 1.13-1.21), and 1.23 (95% CI 1.15-1.32), respectively, when compared to those without the corresponding conditions. The adjusted OR for a diagnosis of VTE associated with a diagnosis of any of the four autoimmune diseases was 1.20 (95% CI 1.16-1.24). The presence of a diagnosis of AIHA, ITP, RA, and SLE was associated with an increased likelihood of having a VTE diagnosis among the group of all non-maternal adult hospitalizations.

Bleeding risk with systemic thrombolytic therapy for pulmonary embolism: scope of the problem

Acute pulmonary embolism represents a major complication of venous thromboembolism that is associated with high morbidity and mortality. Guidelines recommend the rapid initiation of anticoagulation and consideration of thrombolytic therapy in select patients, including those with hypotension or at high risk of developing hypotension. Evaluation for thrombolytic therapy should only be considered after assessment of contraindications and risk for major bleeding. The objective of this perspective article is to evaluate the bleeding risk associated with systemic thrombolytic therapy in the management of acute pulmonary embolism and discuss strategies to minimize this risk. Risk stratification of acute pulmonary embolism will be discussed to identify patient populations that warrant specific consideration of risk for major bleeding with thrombolytic therapy. In addition, the incidence, patient-specific risk factors, and pharmacologic characteristics, including concurrent anticoagulation and thrombolytic therapy, will be evaluated in the context of risk for major hemorrhage. Finally, supporting evidence for strategies to minimize risk of hemorrhage, including evaluation of contraindications, weight adjusted dosing, infusion strategy and catheter-directed thrombolytic administration will be evaluated. Despite published guidelines and review articles, select aspects to thrombolytic therapy for the management of pulmonary embolism remain controversial and under recognized, including risk of major hemorrhage. When making decisions about the role of thrombolytic therapy in pulmonary embolism, clinicians must be knowledgeable about the associated risks of thrombolytic therapy and individually evaluate patient risk factors prior to determining appropriate candidacy for thrombolytic therapy. For patients considered to be at high risk of major bleeding, strategies to minimize risk should be considered, including weight-adjusted doses and catheter directed therapy. Additional research is needed specific to the acute pulmonary embolism setting to validate risk factors and strategies to minimize major hemorrhage.

Venous thromboembolism and varicose veins share familial susceptibility: a nationwide family study in Sweden

Background

Varicose veins (VVs) have been associated with venous thromboembolism (VTE), but whether these diseases share familial susceptibility has not been determined. This nationwide study aimed to determine whether VTE shares familial susceptibility with VVs.

Methods and Results

Swedish Multigeneration Register data for persons aged 0 to 76 years during the period 1964–2008 were linked to the Swedish Inpatient and Outpatient Registers. Familial risks (standardized incidence ratios [SIRs]) of VTE and VVs were examined in 2 ways (ie, bidirectionally): risk of VTE in subjects whose siblings had been diagnosed with VVs and risk of VVs in persons whose siblings had been diagnosed with VTE. The analyses were repeated for spouses to determine the importance of shared adult family environment. In total, 96 810 siblings had VVs and 87 564 had VTE. An increased risk of VTE was observed in persons whose siblings had VVs (SIR 1.30, 95% CI 1.26 to 1.33), whereas persons whose siblings had VTE had an increased risk of VVs (SIR 1.30, 95% CI 1.27 to 1.34). If 2 or more siblings were affected by VTE, the risk for VVs was 1.70 (95% CI 1.53 to 1.88). Conversely, if 2 or more siblings were affected by VVs, the risk for VTE was 1.52 (95% CI 1.38 to 1.67). In spouses of VTE patients, a minor increased risk of VVs was observed (SIR 1.05 for husbands, SIR 1.06 for wives). The risk of VTE in spouses of VV patients was similarly small (SIR 1.01 for husbands, SIR 1.05 for wives).

Conclusions

VVs and VTE share familial susceptibility. This novel finding suggests the existence of shared familial and possibly genetic factors.

Venous thromboembolism in children: details of 46 cases based on a follow-up survey of POSNA members

INTRODUCTION

On the basis of a recent survey of Pediatric Orthopedic Society of North America members, 59% of the respondents acknowledged having encountered at least 1 child with the diagnosis of venous thromboembolism (VTE). The current survey sought further information including patient demographics, underlying diagnosis, presence of certain risk factors for VTE, and the clinical outcome.

METHODS

A follow-up web-based questionnaire was sent to 121 active members of Pediatric Orthopedic Society of North America who had provided their contact information in the prior survey. Thirty-eight respondents provided clinical details on 46 children.

RESULTS

The mean age of the affected patients was 14.3 (95% confidence interval, 13.3-15.3) years and 61% were males. The average body mass index was 28 (95% confidence interval, 25-31). Forty-four percent of the patients were diagnosed with deep venous thrombosis (DVT) only, 26% with pulmonary embolism (PE) only, and 30% with both DVT and PE. Majority of the children had DVT involving the popliteal area or thigh (16 cases each). Lower extremity surgery (29 cases, including proximal femoral/tibial osteotomies, internal fixation of long bone fractures, anterior cruciate ligament reconstruction, and resection of osteochondroma around the knee) and adolescence (28 cases) were the 2 most commonly cited associations. Other cases were noted with spinal surgery (8 children) and musculoskeletal infections (7 children). Three patients developed a postphlebitic syndrome, 1 had recurrent DVT and 2 children died. Both deceased children were diagnosed with DVT and PE including a 9-year-old child with a positive family history of antithrombin-3 deficiency that was not noted preoperatively.

CONCLUSIONS

Although uncommon, potentially fatal VTE can occur among children with a variety of musculoskeletal ailments. Obtaining a family history suggestive of thrombophilia preoperatively should be encouraged. Further investigation is warranted to ascertain the role of prophylaxis against VTE among children in an orthopaedic practice.

LEVEL OF EVIDENCE

Level IV-case series.

Risk marker associations with venous thrombotic events: a cross-sectional analysis

OBJECTIVE

To examine the interrelations among, and risk marker associations for, superficial and deep venous events-superficial venous thrombosis (SVT), deep venous thrombosis (DVT) and pulmonary embolism (PE).

DESIGN

Cross-sectional analysis.

SETTING

San Diego, California, USA.

PARTICIPANTS

2404 men and women aged 40-79 years from four ethnic groups: non-Hispanic White, Hispanic, African-American and Asian. The study sample was drawn from current and former staff and employees of the University of California, San Diego and their spouses/significant others.

OUTCOME MEASURES

Superficial and deep venous events, specifically SVT, DVT, PE and combined deep venous events (DVE) comprising DVT and PE.

RESULTS

Significant correlates on multivariable analysis were, for SVT: female sex, ethnicity (African-American=protective), lower educational attainment, immobility and family history of varicose veins. For DVT and DVE, significant correlates included: heavy smoking, immobility and family history of DVEs (borderline for DVE). For PE, significant predictors included immobility and, in contrast to DVT, blood pressure (BP, systolic or diastolic). In women, oestrogen use duration for hormone replacement therapy, in all and among oestrogen users, predicted PE and DVE, respectively.

CONCLUSIONS

These findings fortify evidence for known risk correlates/predictors for venous disease, such as family history, hormone use and immobility. New risk associations are shown. Striking among these is an association of PE, but not DVT, to elevated BP: we conjecture PE may serve as cause rather than consequence. Future studies should evaluate the temporal direction of this association. Oxidative stress and cell energy compromise are proposed to explain and predict many risk factors, operating through cell-death mediated triggering of coagulation activation.

Impact of a venous thromboembolism prophylaxis "smart order set": Improved compliance, fewer events

Venous thromboembolism (VTE) affects over 700,000 Americans annually. Prophylaxis reduces the risk of VTE by 60% but many patients still do not receive risk-appropriate VTE prophylaxis. To improve our institution's VTE prophylaxis performance, we developed mandatory computerized clinical decision support-enabled "smart order sets" that required providers to assess VTE risk factors and contraindications to pharmacologic prophylaxis. Using provider responses, the order set recommends evidence-based risk-appropriate VTE prophylaxis. To study the impact of our "smart order set" on prescription of risk-appropriate VTE prophylaxis and clinical outcomes, we conducted a retrospective chart review of consecutive patients admitted to the Medicine service during one month immediately prior to (November 2007) and a single month subsequent to (April 2010) order set launch. Data collection included patient demographics, VTE risk factors, and the use and type of VTE prophylaxis. The pre- and post-implementation cohorts contained 1,000 and 942 patients, respectively. After implementation of the "smart order set", the prescription of risk-appropriate VTE prophylaxis increased from 65.6% to 90.1% (P < 0.0001). Orders for any form of VTE prophylaxis increased from 76.4% to 95.6% (P < 0.0001). Radiographically documented symptomatic VTE within 90 days of hospital discharge declined from 2.5% to 0.7% (P = 0.002). Preventable harm was completely eliminated (1.1% to 0%, P = 0.001) with no difference in major bleeding or all-cause mortality. A VTE prophylaxis computerized clinical decision support-enabled "smart order set" improved prescription of risk-appropriate VTE prophylaxis, reduced symptomatic VTE and eliminated preventable harm from VTE without increasing major bleeding.

Hospitalizations of adults ≥60 years of age with venous thromboembolism

We assessed the rates, trends, and factors associated with venous thromboembolism (VTE) diagnosis among hospitalizations of adults ≥60 years of age during the period 2001 to 2010. Data from the National Hospital Discharge Survey were used for this study. During the period 2001 to 2010, the estimated annual number of hospitalizations in which a VTE diagnosis was recorded, among adults ≥ 60 years of age, ranged from approximately 2 70 000 in 2001 to 4 23 000 in 2010. The rate of such hospitalizations per 1 00 000 US population ≥60 years of age ranged from 581 in 2001 to 739 in 2010. During the period 2001 to 2004, there was a significant increasing trend in the rate of hospitalizations with VTE among women ≥60 years of age. The factors positively associated with an increased risk of VTE diagnosis were female sex, summer and autumn seasons (compared with spring), venous catheterization, cancer, and greater length of hospital stay.

Models for thrombin generation and risk of disease

Computational models can offer an integrated view of blood clotting dynamics and may ultimately be instructive regarding an individual's risk of bleeding or clotting. Appropriately, developed and validated models could allow clinicians to simulate the outcomes of therapeutics and estimate risk of disease. Computational models that describe the dynamics of thrombin generation have been developed and have been used in combination with empirical studies to understand thrombin dynamics on a mechanistic basis. The translation of an individual's specific coagulation factor composition data using these models into an integrated assessment of hemostatic status may provide a route for advancing the long-term goal of individualized medicine. This review details the integrated approaches to understanding: (i) What is normal thrombin generation in individuals? (ii) What is the effect of normal range plasma composition variation on thrombin generation in pathologic states? (iii) Can disease progression or anticoagulation be followed by understanding the boundaries of normal thrombin generation defined by plasma composition? (iv) What are the controversies and limitations of current computational approaches? Progress in these areas can bring us closer to developing models that can be used to aid in identifying hemostatic risk.

Is venous thromboembolism in colorectal surgery patients preventable or inevitable? One institution's experience

BACKGROUND

The rate of venous thromboembolism (VTE) in colorectal surgery patients is reportedly high. Herein, we describe characteristics of patients developing VTE in the early postoperative period.

STUDY DESIGN

A retrospective cohort analysis was conducted using institutional comprehensive data on colorectal surgery patients from the National Surgical Quality Improvement Program. All patients from July 2009 to July 2011 were included. Multivariable logistic regression was used to assess which factors were associated with increased risk of developing VTE within 30 days of operation.

RESULTS

There were 615 patients who underwent colorectal surgery. Twenty-five (4.1%) developed VTE; 16 (2.6%) deep venous thrombosis (DVT), 4 (0.7%) pulmonary embolus (PE), and 5 (0.8%) developed both DVT and PE. Among VTE patients, 23 (92%) were ordered risk-appropriate VTE prophylaxis. On multivariable analysis, risk factors associated with VTE included postoperative infection (odds ratio [OR] 4.21, 95% CI 1.79, 9.89; p = 0.001), disseminated cancer (OR 4.38, 95% CI 1.24, 15.42; p = 0.022), and emergent status (OR 2.80, 95% CI 1.15, 6.85; p = 0.024). Fourteen (56.0%) of the 25 VTE patients also developed infectious complications compared with 168 (28.5%) of patients without VTE (p = 0.001). Organ space surgical site infections were the most common infection, present in 7 VTE patients. The infectious complications in 9 (64.3%) of the 14 patients occurred before or the same day as the VTE.

CONCLUSIONS

Most VTE events occurred in colorectal surgery patients ordered current best practice prophylaxis for VTE. Further investigation is warranted to identify patients at increased risk for VTE and to develop new strategies to further reduce the incidence of postoperative VTE.

Pulmonary embolism: the weekend effect

BACKGROUND

Pulmonary embolism is a common, often fatal condition that requires timely recognition and rapid institution of therapy. Previous studies have documented worse outcomes for weekend admissions for a variety of time-sensitive medical conditions. This phenomenon has not been clearly demonstrated for pulmonary embolism.

METHODS

We used the Healthcare Cost and Utilization Project Nationwide Inpatient Sample for the years 2000 to 2008 to identify people with a principal discharge diagnosis of pulmonary embolism. We classified admissions as weekend if they occurred between midnight Friday and midnight Sunday. We compared all-cause in-hospital mortality between weekend and weekday admissions and investigated the timing of inferior vena cava (IVC) filter placement and thrombolytic infusion as potential explanations for differences in mortality.

RESULTS

Unadjusted mortality was higher for weekend admissions than weekday admissions (OR, 1.19; 95% CI, 1.13-1.24). This increase in mortality remained statistically significant after controlling for potential confounding variables (OR, 1.17; 95% CI, 1.11-1.22). Among patients who received an IVC filter, a larger proportion of those admitted on a weekday than on the weekend received it on their first hospital day (38% vs 29%, P < .001). The timing of thrombolytic therapy did not differ between weekday and weekend admissions.

CONCLUSIONS

Weekend admissions for pulmonary embolism were associated with higher mortality than weekday admissions. Our finding that IVC filter placement occurred later in the hospital course for patients admitted on weekends with pulmonary embolism suggests differences in the timeliness of diagnosis and treatment between weekday and weekend admissions. Regardless of cause, physicians should be aware that weekend admissions for pulmonary embolism have a 20% increased risk of death and warrant closer attention than provided during the week.

Thromboprophylaxis in nonsurgical patients

Venous thromboembolism (VTE) is an important cause of preventable morbidity and mortality in medically ill patients. Randomized controlled trials indicate that pharmacologic prophylaxis reduces deep venous thrombosis (relative risk [RR] = 0.46; 95% confidence interval [CI], 0.36-0.59) and pulmonary embolism (RR = 0.49; 95% CI, 0.33-0.72) with a nonsignificant trend toward more bleeding (RR = 1.36; 95% CI, 0.80-2.33]. Low-molecular-weight heparin (LMWH) and unfractionated heparin are equally efficacious in preventing deep venous thrombosis (RR = 0.85; 95% CI, 0.69-1.06) and pulmonary embolism (RR = 1.05; 95% CI, 0.47-2.38), but LMWH is associated with significantly less major bleeding (RR = 0.45; 95% CI, 0.23-0.85). LMWH is favored for VTE prophylaxis in critically ill patients. New VTE and bleeding risk stratification tools offer the potential to improve the risk-benefit ratio for VTE prophylaxis in medically ill patients. Intermittent pneumatic compression devices should be used for VTE prophylaxis in patients with contraindications to pharmacologic prophylaxis. Graduated compression stockings should be used with caution. VTE prevention in medically ill patients using extended-duration VTE prophylaxis and new oral anticoagulants warrant further investigation. VTE prophylaxis prescription and administration rates are suboptimal and warrant multidisciplinary performance improvement strategies.

Correlates of in-hospital deaths among hospitalizations with pulmonary embolism: findings from the 2001-2008 National Hospital Discharge Survey

BACKGROUND

Deep vein thrombosis and pulmonary embolism (PE) are responsible for substantial mortality, morbidity, and impaired health-related quality of life. The aim of this study was to evaluate the correlates of in-hospital deaths among hospitalizations with a diagnosis of PE in the United States.

METHODS

By using data from the 2001-2008 National Hospital Discharge Survey, we assessed the correlates of in-hospital deaths among 14,721 hospitalizations with a diagnosis of PE and among subgroups stratified by age, sex, race, days of hospital stay, type of admission, cancer, pneumonia, and fractures. We produced adjusted rate ratios (aRR) and 95% confidence intervals using log-linear multivariate regression models.

RESULTS

Regardless of the listing position of diagnostic codes, we observed an increased likelihood of in-hospital death in subgroups of hospitalizations with ages 50 years and older (aRR = 1.82-8.48), less than 7 days of hospital stay (aRR = 1.43-1.57), cancer (aRR = 2.10-2.28), pneumonia (aRR = 1.79-2.20), or fractures (aRR = 2.18) (except for first-listed PE), when compared to the reference groups with ages 1-49 years, 7 days or more of hospital stay, without cancer, pneumonia, or fractures while adjusting for covariates. In addition, we observed an increased likelihood of in-hospital death for first-listed PE in hospitalizations of women, when compared to those of men (aRR = 1.45).

CONCLUSIONS

The results of this study provide support for identifying, developing, and implementing effective, evidence-based clinical assessment and management strategies to reduce PE-related morbidity and mortality among hospitalized PE patients who may have concurrent health conditions including cancer, pneumonia, and fractures.

Lessons from the Johns Hopkins Multi-Disciplinary Venous Thromboembolism (VTE) Prevention Collaborative

PROBLEM

Venous thromboembolism (VTE) is a common cause of potentially preventable mortality, morbidity, and increased medical costs. Risk-appropriate prophylaxis can prevent most VTE events, but only a small fraction of patients at risk receive this treatment.

DESIGN

Prospective quality improvement programme.

SETTING

Johns Hopkins Hospital, Baltimore, Maryland, USA.

STRATEGIES FOR CHANGE

A multidisciplinary team established a VTE Prevention Collaborative in 2005. The collaborative applied the four step TRIP (translating research into practice) model to develop and implement a mandatory clinical decision support tool for VTE risk stratification and risk-appropriate VTE prophylaxis for all hospitalised adult patients. Initially, paper based VTE order sets were implemented, which were then converted into 16 specialty-specific, mandatory, computerised, clinical decision support modules.

KEY MEASURES FOR IMPROVEMENT

VTE risk stratification within 24 hours of hospital admission and provision of risk-appropriate, evidence based VTE prophylaxis.

EFFECTS OF CHANGE

The VTE team was able to increase VTE risk assessment and ordering of risk-appropriate prophylaxis with paper based order sets to a limited extent, but achieved higher compliance with a computerised clinical decision support tool and the data feedback which it enabled. Risk-appropriate VTE prophylaxis increased from 26% to 80% for surgical patients and from 25% to 92% for medical patients in 2011.

LESSONS LEARNT

A computerised clinical decision support tool can increase VTE risk stratification and risk-appropriate VTE prophylaxis among hospitalised adult patients admitted to a large urban academic medical centre. It is important to ensure the tool is part of the clinician's normal workflow, is mandatory (computerised forcing function), and offers the requisite modules needed for every clinical specialty.

Diagnostic approach to deep venous thrombosis and pulmonary embolism in the critical care setting

Considerable progress has been made during the last 30 years in the prevention, diagnosis, and therapy of venous thromboembolism. This article discusses the epidemiology, pathophysiology, and clinical presentation of the disease as well as the diagnostic uncertainty that exists in the critical care setting. Diagnostic approaches for deep venous thrombosis and pulmonary embolism are considered, including clinical prediction rules, D-dimer, contrast venography, duplex ultrasonography, computed tomographic angiography and venography, magnetic resonance imaging, ventilation–perfusion scanning, chest radiograph, arterial blood gases, electrocardiography, and echocardiography.