Diagnostic management of acute pulmonary embolism: a prediction model based on a patient data meta-analysis.

AIMS: Risk stratification is used for decisions regarding need for imaging in patients with clinically suspected acute pulmonary embolism (PE). The aim was to develop a clinical prediction model that provides an individualized, accurate probability estimate for the presence of acute PE in patients with suspected disease based on readily available clinical items and D-dimer concentrations. METHODS AND RESULTS: An individual patient data meta-analysis was performed based on sixteen cross-sectional or prospective studies with data from 28 305 adult patients with clinically suspected PE from various clinical settings, including primary care, emergency care, hospitalized and nursing home patients. A multilevel logistic regression model was built and validated including ten a priori defined objective candidate predictors to predict objectively confirmed PE at baseline or venous thromboembolism (VTE) during follow-up of 30 to 90 days. Multiple imputation was used for missing data. Backward elimination was performed with a P-value <0.10. Discrimination (c-statistic with 95% confidence intervals [CI] and prediction intervals [PI]) and calibration (outcome:expected [O:E] ratio and calibration plot) were evaluated based on internal-external cross-validation. The accuracy of the model was subsequently compared with algorithms based on the Wells score and D-dimer testing. The final model included age (in years), sex, previous VTE, recent surgery or immobilization, haemoptysis, cancer, clinical signs of deep vein thrombosis, inpatient status, D-dimer (in µg/L), and an interaction term between age and D-dimer. The pooled c-statistic was 0.87 (95% CI, 0.85-0.89; 95% PI, 0.77-0.93) and overall calibration was very good (pooled O:E ratio, 0.99; 95% CI, 0.87-1.14; 95% PI, 0.55-1.79). The model slightly overestimated VTE probability in the lower range of estimated probabilities. Discrimination of the current model in the validation data sets was better than that of the Wells score combined with a D-dimer threshold based on age (c-statistic 0.73; 95% CI, 0.70-0.75) or structured clinical pretest probability (c-statistic 0.79; 95% CI, 0.76-0.81). CONCLUSION: The present model provides an absolute, individualized probability of PE presence in a broad population of patients with suspected PE, with very good discrimination and calibration. Its clinical utility needs to be evaluated in a prospective management or impact study. REGISTRATION: PROSPERO ID 89366.

Apixaban thromboprophylaxis in ambulatory patients with cancer and obesity: Insights from the AVERT trial.

BACKGROUND: The use of direct oral anticoagulants (DOACs) in obese patients is uncertain. It is unclear if body mass index (BMI) affects the safety and efficacy of DOACs for the primary prevention of venous thromboembolism (VTE) in high-risk ambulatory patients with cancer. We sought to determine the outcomes associated with the use of apixaban for the primary prevention of cancer-associated VTE according to BMI. METHODS: The randomized, double-blinded, placebo-controlled AVERT trial evaluated apixaban thromboprophylaxis in intermediate-to-high risk ambulatory cancer patients receiving chemotherapy. For this post-hoc analysis, the primary efficacy and safety outcomes were objectively confirmed VTE and clinically relevant bleeding (major and clinically relevant non-major bleeding), respectively. Obesity was defined as BMI ≥30 kg/m2. RESULTS: Among 574 patients randomized, 217 (37.8 %) patients had BMI ≥30 kg/m2. Obese patients were overall younger, more likely to be female, had higher creatinine clearance and hemoglobin, lower platelet count, and better ECOG performance status. Compared to placebo, apixaban thromboprophylaxis was associated with reduced VTE in both obese (hazard ratio [HR] 0.26; 95 % confidence interval [CI], 0.14-0.46; p < 0.0001) and non-obese (HR 0.54; 95%CI, 0.29-1.00; p = 0.049) patients. The HR for clinically relevant bleeding (apixaban vs. placebo) was numerically higher in obese (2.09; 95%CI, 0.96-4.51; p = 0.062) than non-obese subjects (1.23; 95%CI, 0.71-2.13; p = 0.46), but overall in line with the risks observed in the general trial population. CONCLUSIONS: In the AVERT trial enrolling ambulatory cancer patients receiving chemotherapy, we found no substantial differences in the efficacy or safety of apixaban thromboprophylaxis across obese and non-obese subjects.

Efficacy and safety of apixaban for primary prevention of thromboembolism in patients with cancer and a central venous catheter: A subgroup analysis of the AVERT Trial.

INTRODUCTION: Central venous catheters (CVC) are associated with an increased risk of venous thromboembolism (VTE) in patients with cancer. Primary thromboprophylaxis using a direct oral anticoagulant decreases the risk of VTE in intermediate-to-high risk ambulatory cancer patients. We assessed the efficacy and safety of thromboprophylaxis with apixaban in the subpopulation of patients with cancer and a CVC in the AVERT trial. METHODS: The AVERT study was a randomized, placebo-controlled, double-blind clinical trial assessing the efficacy and safety of apixaban for primary thromboprophylaxis in patients with cancer initiating chemotherapy who were at intermediate to high risk of VTE. The primary efficacy outcome was objectively confirmed VTE within 180 days of randomization and the primary safety outcome was major bleeding. The hazard ratios (HRs) were calculated using a Cox regression model controlling for age, gender, and center. RESULTS: A total of 217 patients had a CVC and were included in the subgroup analyses with 126 and 91 patients receiving apixaban or placebo, respectively. VTE occurred in 6 (4.8%) patients in the apixaban group and 17 (18.7%) patients in the placebo group (HR 0.26; 95% CI, 0.14-0.47; p < 0.0001). Major bleeding occurred in 2 (1.6%) patients in the apixaban group and 2 (2.2%) patients in the placebo group (HR 0.69; 95% CI, 0.20-2.35; p = 0.556). CONCLUSIONS: Primary thromboprophylaxis with apixaban in patients with cancer and a CVC was associated with a reduced risk of VTE in the AVERT study population, without an increased risk of bleeding. (Funded by the CIHR and Bristol-Myers Squibb-Pfizer Alliance; NCT02048865).

Safety and Efficiency of Diagnostic Strategies for Ruling Out Pulmonary Embolism in Clinically Relevant Patient Subgroups : A Systematic Review and Individual-Patient Data Meta-analysis.

BACKGROUND: How diagnostic strategies for suspected pulmonary embolism (PE) perform in relevant patient subgroups defined by sex, age, cancer, and previous venous thromboembolism (VTE) is unknown. PURPOSE: To evaluate the safety and efficiency of the Wells and revised Geneva scores combined with fixed and adapted D-dimer thresholds, as well as the YEARS algorithm, for ruling out acute PE in these subgroups. DATA SOURCES: MEDLINE from 1 January 1995 until 1 January 2021. STUDY SELECTION: 16 studies assessing at least 1 diagnostic strategy. DATA EXTRACTION: Individual-patient data from 20 553 patients. DATA SYNTHESIS: Safety was defined as the diagnostic failure rate (the predicted 3-month VTE incidence after exclusion of PE without imaging at baseline). Efficiency was defined as the proportion of individuals classified by the strategy as "PE considered excluded" without imaging tests. Across all strategies, efficiency was highest in patients younger than 40 years (47% to 68%) and lowest in patients aged 80 years or older (6.0% to 23%) or patients with cancer (9.6% to 26%). However, efficiency improved considerably in these subgroups when pretest probability-dependent D-dimer thresholds were applied. Predicted failure rates were highest for strategies with adapted D-dimer thresholds, with failure rates varying between 2% and 4% in the predefined patient subgroups. LIMITATIONS: Between-study differences in scoring predictor items and D-dimer assays, as well as the presence of differential verification bias, in particular for classifying fatal events and subsegmental PE cases, all of which may have led to an overestimation of the predicted failure rates of adapted D-dimer thresholds. CONCLUSION: Overall, all strategies showed acceptable safety, with pretest probability-dependent D-dimer thresholds having not only the highest efficiency but also the highest predicted failure rate. From an efficiency perspective, this individual-patient data meta-analysis supports application of adapted D-dimer thresholds. PRIMARY FUNDING SOURCE: Dutch Research Council. (PROSPERO: CRD42018089366).

Diagnosing deep vein thrombosis in cancer patients with suspected symptoms: An individual participant data meta-analysis.

BACKGROUND: A previous individual participant data (IPD) meta-analysis showed that the Wells rule and D-dimer testing cannot exclude suspected deep vein thrombosis (DVT) in cancer patients. OBJECTIVES: To explore reasons for this reduced diagnostic accuracy and to optimize the diagnostic pathway for cancer patients suspected of DVT. PATIENTS AND METHODS: Using IPD from 13 studies in patients with suspected DVT, DVT prevalence and the predictive value of the Wells rule items and D-dimer testing were compared between patients with and without cancer. Next, we developed a prediction model with five variables selected from all available diagnostic predictors. RESULTS: Among the 10 002 suspected DVT patients, there were 834 patients with cancer. The median prevalence of DVT in these patients with cancer was 37.5% (interquartile range [IQR], 30.8-45.5), whereas it was 15.1% (IQR, 11.5-16.7) in patients without cancer. Diagnostic performance of individual Wells rule items and D-dimer testing was similar across patients with and without cancer, except "immobility" and "history of DVT." The newly developed rule showed a pooled c-statistic 0.80 (95% confidence interval [CI], 0.75-0.83) and good calibration. However, using this model, still only 4.3% (95% CI, 3.0-5.7) of the suspected patients with cancer could be identified with a predicted DVT posttest probability of <2%. CONCLUSIONS: Likely because of the high prevalence of DVT, clinical models followed by D-dimer testing fail to rule out DVT efficiently in cancer patients suspected of DVT. Direct referral for compression ultrasonography appears to be the preferred approach for diagnosis of suspected DVT in cancer patients.

Association between rivaroxaban use and length of hospital stay, treatment costs and early outcomes in patients with pulmonary embolism: a systematic review of real-world studies.

BACKGROUND: In the EINSTEIN-Pulmonary Embolism (PE) trial, subjects randomized to rivaroxaban versus enoxaparin bridging to vitamin K antagonist (VKA) therapy experienced a reduced index hospital length of stay (LOS). We sought to conduct a systematic review of real-world studies comparing LOS, costs and early outcomes among patients treated with rivaroxaban or parenterally bridged VKA in routine practice. METHODS: We searched Medline and Scopus from 1 January 2011 to 30 November 2016 to identify observational studies comparing acute PE patients anticoagulated with rivaroxaban or parenterally bridged VKA and reporting data on index hospital LOS, costs and/or early post-PE outcomes. Studies not using appropriate methods for minimizing confounding bias or not published in English were excluded. RESULTS: Five studies met inclusion criteria. Rivaroxaban use was associated with decreased index hospital LOS (range: 1.36-1.70 days) and treatment costs (range: $1818-$2688) during an index stay compared to parenterally bridged warfarin. No differences in early readmission for recurrent thrombosis were noted between anticoagulation strategies. Readmission for major bleeding was rare in both cohorts. Similar reductions in LOS (range: 0.23-4.3 days) and costs (range: $251-$7094) were observed with rivaroxaban in studies restricted to patients deemed low risk for early complications by clinical gestalt or by a clinical- or claims-based risk stratification tool. CONCLUSIONS: Regardless of patient predicted risk of post-PE complications, real-world studies suggest that rivaroxaban is associated with a reduced hospital LOS and costs versus parenterally bridged warfarin, without increasing readmission.

Pulmonary embolism: Epidemiology and registries.

Real-life data is important in understanding the needs of patients in routine clinical practice, particularly owing to the fact that almost a quarter of patients with venous thromoboembolism (VTE) have at least one exclusion criterion preventing their recruitment into randomized clinical trials. The Registro Informatizado de Enfermedad Trombo Embólica (RIETE) registry is an ongoing, international, multicentre, prospective registry of consecutive patients presenting with acute VTE. In this chapter, we summarized some of the most relevant data concerning the epidemiology of VTE in the RIETE registry.

Nurse clinic versus home delivery of evidence-based community leg ulcer care: a randomized health services trial.

BACKGROUND: International studies report that nurse clinics improve healing rates for the leg ulcer population. However, these studies did not necessarily deliver similar standards of care based on evidence in the treatment venues (home and clinic). A rigorous evaluation of home versus clinic care is required to determine healing rates with equivalent care and establish the acceptability of clinic-delivered care. METHODS: Health Services RCT was conducted where mobile individuals were allocated to either home or nurse clinic for leg ulcer management. In both arms, care was delivered by specially trained nurses, following an evidence protocol. PRIMARY OUTCOME: 3-month healing rates. SECONDARY OUTCOMES: durability of healing (recurrence), time free of ulcers, HRQL, satisfaction, resource use. Data were collected at base-line, every 3 months until healing occurred, with 1 year follow-up. Analysis was by intention to treat. RESULTS: 126 participants, 65 randomized to receive care in their homes, 61 to nurse-run clinics. No differences found between groups at baseline on socio-demographic, HRQL or clinical characteristics. mean age 69 years, 68% females, 84% English-speaking, half with previous episode of ulceration, 60% ulcers at inclusion < 5 cm2 for < 6 months. No differences in 3-month healing rates: clinic 58.3% compared to home care at 56.7% (p = 0.5) or in secondary outcomes. CONCLUSION: Our findings indicate that organization of care not the setting where care is delivered influences healing rates. Key factors are a system that supports delivery of evidence-based recommendations with care being provided by a trained nursing team resulting in equivalent healing rates, HRQL whether care is delivered in the home or in a community nurse-led clinic. TRIAL REGISTRATION: ClinicalTrials.gov Protocol Registration System: NCT00656383.

Prospective assessment of the natural history of positive D-dimer results in persons with acute venous thromboembolism (DVT or PE).

The natural history of initially positive D-dimers for venous thromboembolism is not known. If it returns to negative in the majority of patients, it would be potentially helpful to diagnose a recurrence. In this study, we prospectively measured D-dimer levels in outpatients with a diagnosis of venous thromboembolism. There were a total of 152 patients with an average age of 57. D-dimer results were performed at baseline and repeated at one week, one month and three months. At baseline 120 of 152 (79%) had a positive D-dimer result. Of those with an initially positive result, 80% were still positive at one week and 39% were still positive at one month. Finally at three months, 13% remained positive. Seven patients had recurrent events and all had persistently elevated D-dimers at one month. This study suggests that a persistently positive D-dimer result after one month of treatment may indicate a higher risk of recurrent venous thromboembolism. D-dimer testing for the diagnosis of recurrence of venous thromboembolism deserves further study.