Accuracy of physicians' intuitive risk estimation in the diagnostic management of pulmonary embolism: an individual patient data meta-analysis

BACKGROUND

In patients clinically suspected of having pulmonary embolism (PE), physicians often rely on intuitive estimation ("gestalt") of PE presence. Although shown to be predictive, gestalt is criticized for its assumed variation across physicians and lack of standardization.

OBJECTIVES

To assess the diagnostic accuracy of gestalt in the diagnosis of PE and gain insight into its possible variation.

METHODS

We performed an individual patient data meta-analysis including patients suspected of having PE. The primary outcome was diagnostic accuracy of gestalt for the diagnosis of PE, quantified as risk ratio (RR) between gestalt and PE based on 2-stage random-effect log-binomial meta-analysis regression as well as gestalts' sensitivity and specificity. The variability of these measures was explored across different health care settings, publication period, PE prevalence, patient subgroups (sex, heart failure, chronic lung disease, and items of the Wells score other than gestalt), and age.

RESULTS

We analyzed 20 770 patients suspected of having PE from 16 original studies. The prevalence of PE in patients with and without a positive gestalt was 28.8% vs 9.1%, respectively. The overall RR was 3.02 (95% CI, 2.35-3.87), and the overall sensitivity and specificity were 74% (95% CI, 68%-79%) and 61% (95% CI, 53%-68%), respectively. Although variation was observed across individual studies (I2, 90.63%), the diagnostic accuracy was consistent across all subgroups and health care settings.

CONCLUSION

A positive gestalt was associated with a 3-fold increased risk of PE in suspected patients. Although variation was observed across studies, the RR of gestalt was similar across prespecified subgroups and health care settings, exemplifying its diagnostic value for all patients suspected of having PE.

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.

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).

Ruling out pulmonary embolism across different healthcare settings: A systematic review and individual patient data meta-analysis

BACKGROUND

The challenging clinical dilemma of detecting pulmonary embolism (PE) in suspected patients is encountered in a variety of healthcare settings. We hypothesized that the optimal diagnostic approach to detect these patients in terms of safety and efficiency depends on underlying PE prevalence, case mix, and physician experience, overall reflected by the type of setting where patients are initially assessed. The objective of this study was to assess the capability of ruling out PE by available diagnostic strategies across all possible settings.

METHODS AND FINDINGS

We performed a literature search (MEDLINE) followed by an individual patient data (IPD) meta-analysis (MA; 23 studies), including patients from self-referral emergency care (n = 12,612), primary healthcare clinics (n = 3,174), referred secondary care (n = 17,052), and hospitalized or nursing home patients (n = 2,410). Multilevel logistic regression was performed to evaluate diagnostic performance of the Wells and revised Geneva rules, both using fixed and adapted D-dimer thresholds to age or pretest probability (PTP), for the YEARS algorithm and for the Pulmonary Embolism Rule-out Criteria (PERC). All strategies were tested separately in each healthcare setting. Following studies done in this field, the primary diagnostic metrices estimated from the models were the "failure rate" of each strategy-i.e., the proportion of missed PE among patients categorized as "PE excluded" and "efficiency"-defined as the proportion of patients categorized as "PE excluded" among all patients. In self-referral emergency care, the PERC algorithm excludes PE in 21% of suspected patients at a failure rate of 1.12% (95% confidence interval [CI] 0.74 to 1.70), whereas this increases to 6.01% (4.09 to 8.75) in referred patients to secondary care at an efficiency of 10%. In patients from primary healthcare and those referred to secondary care, strategies adjusting D-dimer to PTP are the most efficient (range: 43% to 62%) at a failure rate ranging between 0.25% and 3.06%, with higher failure rates observed in patients referred to secondary care. For this latter setting, strategies adjusting D-dimer to age are associated with a lower failure rate ranging between 0.65% and 0.81%, yet are also less efficient (range: 33% and 35%). For all strategies, failure rates are highest in hospitalized or nursing home patients, ranging between 1.68% and 5.13%, at an efficiency ranging between 15% and 30%. The main limitation of the primary analyses was that the diagnostic performance of each strategy was compared in different sets of studies since the availability of items used in each diagnostic strategy differed across included studies; however, sensitivity analyses suggested that the findings were robust.

CONCLUSIONS

The capability of safely and efficiently ruling out PE of available diagnostic strategies differs for different healthcare settings. The findings of this IPD MA help in determining the optimum diagnostic strategies for ruling out PE per healthcare setting, balancing the trade-off between failure rate and efficiency of each strategy.

Perioperative management of non-deferrable oncologic surgeries during COVID-19 pandemic in Madrid, Spain. Is it safe?

Introduction

Surgical treatment during Covid-19 pandemic is controversial. Currently, most clinical guidelines advise to defer surgical patients during the Covid-19 pandemic, although the supporting data is sparse. We assumed that a Covid-19-free hospital, on the back of strong isolation measures and targeted screening, could reduce complications and enable us to continue treating high-risk patients.

Methods

Prospective study with retrospective analysis of 355 patients who had undergone nondeferrable oncological surgery between March 16th, 2020, and April 14th, 2020, at our institution. The aim of the study was to assess the hospital restructuring and surgical protocols to be able to safely handle non-deferrable surgeries during the first wave of the Covid-19 pandemic. We implemented structural changes and an updated surgical-anesthetic protocol in order to isolate Covid-19 patients from other surgical patients. Comprehensive targeted screening for Covid-19 patients was made. PCR tests were requested for suspected Covid-19 patients. We analyzed mortality and complications related to both surgery and Covid-19 during hospital admission and also 15 and 30 days after surgery. We compared it with a sample of similar patients in the pre-pandemic period.

Results

Of the 355 patients enrolled in our study, 21 were removed due to Covid-19 infection, leaving a total of 334 patients in our final analysis. Post-operative complications were found in 37 patients (11.07%). Two patients died after surgery (0.6%). At the end of the study, Covid-19-related adverse outcomes were detected in six patients (1.79%). When comparing the complications of our original sample with the complications that occurred in the pre-covid era, we found no statistically significant differences.

Conclusions

Our results show that the surgical treatment of oncologic patients during the Covid-19 pandemic is safe, as long as the hospital performs surgeries under strict isolation measures and a robust screening method. It is necessary to select Covid-19 free hospitals for this matter in this and future pandemics.

Perioperative management of non-deferrable oncologic surgeries during COVID-19 pandemic in Madrid, Spain. Is it safe?

INTRODUCTION

Surgical treatment during COVID-19 pandemic is controversial. Currently, most clinical guidelines advise to defer surgical patients during the COVID-19 pandemic, although the supporting data is sparse. We assumed that a COVID-19-free hospital, on the back of strong isolation measures and targeted screening, could reduce complications and enable us to continue treating high-risk patients.

METHODS

Prospective study with retrospective analysis of 355 patients who had undergone nondeferrable oncological surgery between March 16th, 2020, and April 14th, 2020, at our institution. The aim of the study was to assess the hospital restructuring and surgical protocols to be able to safely handle non-deferrable surgeries during the first wave of the COVID-19 pandemic. We implemented structural changes and an updated surgical-anesthetic protocol in order to isolate COVID-19 patients from other surgical patients. Comprehensive targeted screening for COVID-19 patients was made. PCR tests were requested for suspected COVID-19 patients. We analyzed mortality and complications related to both surgery and COVID-19 during hospital admission and also 15 and 30 days after surgery. We compared it with a sample of similar patients in the pre-pandemic period.

RESULTS

Of the 355 patients enrolled in our study, 21 were removed due to COVID-19 infection, leaving a total of 334 patients in our final analysis. Post-operative complications were found in 37 patients (11.07%). Two patients died after surgery (0.6%). At the end of the study, COVID-19-related adverse outcomes were detected in six patients (1.79%). When comparing the complications of our original sample with the complications that occurred in the pre-COVID era, we found no statistically significant differences.

CONCLUSIONS

Our results show that the surgical treatment of oncologic patients during the COVID-19 pandemic is safe, as long as the hospital performs surgeries under strict isolation measures and a robust screening method. It is necessary to select COVID-19 free hospitals for this matter in this and future pandemics.

COVID-19: gynecologic cancer surgery at a single center in Madrid

Objectives

While numerous medical facilities have been forced to suspend oncological surgery due to system overload, debate has emerged on using non-surgical options on cancer cases during the pandemic. The goal of our study was to analyze, in a retrospective cohort study, the results of gynecological cancer surgery and evaluate postoperative complications in a single center in one of the most affected areas in Europe.

Methods

We retrospectively analyzed the records of patients who were referred between March 2020 and May 2020 for primary surgical treatment of breast, endometrial, ovarian, cervical, or vulvar cancer.

Results

The study included a total of 126 patients. Median age was 60 years (range 29–89). Patients were referred with breast (76/126, 60.3%), endometrial (29/126, 23%), ovarian (14/126, 11.1%), cervical (5/126, 4%), or vulvar cancer (2/126, 1.6%). Polymerase chain reaction (PCR) test for detection of severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) was only conducted in 50% of cases due to the low availability of tests during the first phase of our study, and was indicated only in suspected cases according to the healthcare authorities' protocol. Median hospital stay was 1 day (range 0–18). Excluding breast surgery, laparoscopy was the most used procedure (43/126, 34.1%). 15 patients had a postoperative complication (15/126, 11.9%); only in 2 patients (2/15 13.3%) were there reports of Clavien–Dindo grade 3 or 4 complications. 6 patients tested positive for COVID-19 following a PCR diagnostic test, and these surgeries were cancelled.

Conclusions

Adequate protective measures in the setting of COVID-19 free institutions enabled the continuity of cancer surgery without significant compromise of the safety of patients or healthcare workers.

The original and simplified Wells rules and age-adjusted D-dimer testing to rule out pulmonary embolism: an individual patient data meta-analysis

Essentials Evidence for the simplified Wells rule in ruling out acute pulmonary embolism (PE) is scarce. This was a post-hoc analysis on data from 6 studies comprising 7268 patients with suspected PE. The simplified Wells rule combined with age-adjusted D-dimer testing may safely rule out PE. Given its ease of use, the simplified Wells rule is to be preferred over the original Wells rule.

SUMMARY

Background The Wells score and D-dimer testing can safely rule out pulmonary embolism (PE). A simplification of the Wells score has been proposed to improve clinical applicability, but evidence on its performance is scarce. Objectives To compare the performances of the original and simplified Wells scores alone and in combination with age-adjusted D-dimer testing. Methods Individual patient data from 7268 patients with suspected PE enrolled in six management studies were used to evaluate the discriminatory performances of the original and simplified Wells scores. The efficiency and failure rate of the dichotomized original and simplified scores combined with age-adjusted D-dimer testing were compared by use of a one-stage random effects meta-analysis. Efficiency was defined as the proportion of patients in whom PE could be considered to be excluded on the basis of a 'PE unlikely' Wells score and a negative age-adjusted D-dimer test result. Failure rate was defined as the proportion of patients with symptomatic venous thromboembolism during a 3-month follow-up. Results The discriminatory performances of the original and simplified Wells scores were comparable (c-statistic 0.73 [95% confidence interval (CI) 0.72-0.75] versus 0.72 [95% CI 0.70-0.73]). When combined with age-adjusted D-dimer testing, the original and simplified Wells rules had comparable efficiency (3% [95% CI 25-42%] versus 30% [95% CI 21-40%]) and failure rates (0.9% [95% CI 0.6-1.5%] versus 0.8% [95% CI 0.5-1.3%]). Conclusion The original and simplified Wells rules combined with age-adjusted D-dimer testing have similar performances in ruling out PE. Given its ease of use in clinical practice, the simplified Wells rule is to be preferred.

Is stand-alone D-dimer testing safe to rule out acute pulmonary embolism?

Essentials A stand-alone D-dimer below 750 μg/L has been proposed to rule out acute pulmonary embolism (PE). This was a post-hoc analysis on data from 6 studies comprising 7268 patients with suspected PE. The negative predictive value of a D-dimer <750 μg/L ranged from 79% to 96% in various subgroups. Stand-alone D-dimer testing seems to be unsafe to rule out PE in all patients.

SUMMARY

Background Recently, stand-alone D-dimer testing at a positivity threshold of 750 μg L-1 has been proposed as a safe and efficient approach to rule out acute pulmonary embolism (PE), without additional imaging, but this approach needs validation. Objectives To evaluate stand-alone D-dimer testing at a positivity threshold of 750 μg L-1 to rule out PE. Methods Individual data from 7268 patients with suspected PE previously enrolled in six prospective management studies were used. Patients were assessed by the Wells rule followed by quantitative D-dimer testing in those with a 'PE unlikely' score. Patients were classified post hoc as having a negative (< 750 μg L-1 ) or positive (≥ 750 μg L-1 ) D-dimer. Using a one-stage meta-analytic approach, the negative predictive value (NPV) of stand-alone D-dimer testing was evaluated overall and in different risk subgroups. Results The pooled incidence of PE was 23% (range, 13-42%). Overall, 44% of patients had a D-dimer < 750 μg L-1 , of whom 2.8% were diagnosed with PE at baseline or during 3-month follow-up (NPV, 97.2%; 95% confidence interval [CI], 94.9-98.5). The NPV was highest in patients with a low probability of PE according to the Wells rule (99.2%; 95% CI, 98.6-99.5%) and lowest in those with a high probability of PE (79.3%; 95% CI, 53.0-92.8%). The NPVs in patients with active cancer, patients with previous venous thromboembolism and inpatients were 96.2% (95% CI, 85.6-99.1%), 94.7% (95% CI, 88.6-97.6%) and 92.7% (95% CI, 79.3-97.7%), respectively. Conclusions Our findings suggest that stand-alone D-dimer testing at a positivity threshold of 750 μg L-1 is not safe to rule out acute PE.

Wells Rule and d-Dimer Testing to Rule Out Pulmonary Embolism: A Systematic Review and Individual-Patient Data Meta-analysis

BACKGROUND

The performance of different diagnostic strategies for pulmonary embolism (PE) in patient subgroups is unclear.

PURPOSE

To evaluate and compare the efficiency and safety of the Wells rule with fixed or age-adjusted d-dimer testing overall and in inpatients and persons with cancer, chronic obstructive pulmonary disease, previous venous thromboembolism, delayed presentation, and age 75 years or older.

DATA SOURCES

MEDLINE and EMBASE from 1 January 1988 to 13 February 2016.

STUDY SELECTION

6 prospective studies in which the diagnostic management of PE was guided by the dichotomized Wells rule and quantitative d-dimer testing.

DATA EXTRACTION

Individual data of 7268 patients; risk of bias assessed by 2 investigators with the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies 2) tool.

DATA SYNTHESIS

The proportion of patients in whom imaging could be withheld based on a "PE-unlikely" Wells score and a negative d-dimer test result (efficiency) was estimated using fixed (≤500 µg/L) and age-adjusted (age × 10 µg/L in patients aged >50 years) d-dimer thresholds; their 3-month incidence of symptomatic venous thromboembolism (failure rate) was also estimated. Overall, efficiency increased from 28% to 33% when the age-adjusted (instead of the fixed) d-dimer threshold was applied. This increase was more prominent in elderly patients (12%) but less so in inpatients (2.6%). The failure rate of age-adjusted d-dimer testing was less than 3% in all examined subgroups.

LIMITATION

Post hoc analysis, between-study differences in patient characteristics, use of various d-dimer assays, and limited statistical power to assess failure rate.

CONCLUSION

Age-adjusted d-dimer testing is associated with a 5% absolute increase in the proportion of patients with suspected PE in whom imaging can be safely withheld compared with fixed d-dimer testing. This strategy seems safe across different high-risk subgroups, but its efficiency varies.

PRIMARY FUNDING SOURCE

None.

Clinical usefulness and safety of an age-adjusted D-dimer cutoff levels to exclude pulmonary embolism: a retrospective analysis

Age-adjusted D-dimer (AADD) appears to increase the proportion of patients in whom pulmonary embolism (PE) can safely be excluded compared with conventional D-dimer (CDD), according to a limited number of studies. The aim if this study was to assess whether the use of an AADD might safely increase the clinical usefulness of CDD for the diagnosis of PE in our setting. Three hundred and sixty two consecutive outpatients with clinically suspected PE in whom plasma samples were obtained to measure D-dimer were included in this post hoc analysis of a previous study. CDD cutoff value was 500 ng/mL and AADD was calculated as (patient's age × 10) ng/mL in patients aged >50. Sensitivity, specificity, clinical usefulness (i.e., proportion of true-negative tests among all patients with suspected PE), and the proportion of false negatives were calculated for both AADD and CDD among patients with low-to-moderate clinical probability of PE according to Well's criteria. PE was confirmed in 98 patients (27%). Among 331 patients with low-to-moderate clinical probability of PE, sensitivity and clinical usefulness were 100 and 27.8% for CDD, respectively, and 100 and 36.5% for AADD, respectively. In 29 patients aged >50 with CDD >500 ng/mL, AADD showed values under its normal cutoff point, without false negatives for the diagnosis of PE (0%, 95% CI 0-11%). AADD increases clinical usefulness notably with respect to that of CDD in patients with clinical suspected PE without losing sensitivity in our cohort. The use of AADD apparently does not reduce the safety of CDD for the exclusion of PE.

Effectiveness of a diagnostic algorithm combining clinical probability, D-dimer testing, and computed tomography in patients with suspected pulmonary embolism in an emergency department

OBJECTIVE

The aim of our study was to assess the clinical effectiveness of a simplified algorithm using the Wells clinical decision rule, D-dimer testing, and computed tomography (CT) in patients with suspected pulmonary embolism (PE) in an Emergency Department (ED).

METHODS

Patients with clinically suspected PE from the Emergency Department were included from May 2007 through December 2008. Clinical probability was assessed using the Wells clinical decision rule and a VIDAS D-dimer assay was used to measure D-dimer concentration. Patients were categorized as "pulmonary embolism unlikely" or "pulmonary embolism likely" using the dichotomized version of the Wells clinical decision rule. Pulmonary embolism was considered excluded in patients with unlikely probability and normal D-dimer test (< 500 ng/ml). All other patients underwent CT, and pulmonary embolism was considered present or excluded based on the results. Anticoagulants were withheld from patients classified as excluded, and all patients were followed up for 3 months.

RESULTS

241 patients were included in the study. The prevalence of PE in the entire population was 23.6%. The combination of unlikely probability using the dichotomized Wells clinical decision rule and a normal D-dimer level occurred in 23.6%, thus making CT unnecessary. During the followup period, no thromboembolic events were recorded and there were no deaths related to venous thromboembolic disease (3-month thromboembolic risk 0% [95% CI, 0%-8%]).

CONCLUSIONS

In this study we have confirmed the effectiveness of a diagnostic management strategy using a simple clinical decision rule, D-dimer testing, and CT in the evaluation and management of patients with clinically suspected pulmonary embolism.

[Transient global amnesia after general anaesthesia]

Transient global amnesia is a neurological syndrome in which there is a sudden and brief inability to form new memories, as well as an intense retrograde amnesia. However, awareness, personal identity and attention remain intact. It is an uncommon condition seen after an anaesthetic procedure. There are several aetiopathogenic hypotheses (epileptic, migrainous or ischaemic origin) and triggering factors (pain, anxiety, temperature changes, exercise, Valsalva manoeuvres, diagnostic tests or certain drugs). We describe the case of a patient with a high level of pre-operative anxiety who suffered an episode of transient global amnesia after undergoing otolaryngology surgery. With an acute and continued amnesia after general anaesthesia, the first thing that must be done is to establish a suitable differencial diagnosis, which should include transient global amnesia, as this is mainly an exclusion diagnosis. Preoperative anxiety may be a triggering factor to take into account in this condition, with anxiolytic treatment prior to the surgery being important.

Safety of withholding anticoagulant therapy in patients with suspected pulmonary embolism with a negative multislice computed tomography pulmonary angiography

BACKGROUND

To assess the safety of withholding anticoagulant therapy in patients with clinically suspected pulmonary embolism with a negative multislice computed tomography pulmonary angiography (MCTPA).

METHODS

Three hundred and eighty six patients who were consecutively assessed in the emergency room of our institution for suspected pulmonary embolism were eligible for our study. Patients with either a low or an intermediate clinical probability of pulmonary embolism according to the Wells score and a negative MCTPA for pulmonary embolism were enrolled. Patients with anticoagulant therapy for other medical conditions were excluded from this study. We assessed the percentage of patients in whom venous thromboembolic events or death related to this condition within three months after the negative CT.

RESULTS

Two hundred and forty two patients were included in our series [mean age+/-standard deviation (SD) (63.1+/-18.1)]. Only one patient (0.41% [95% confidence interval -0.4%-1.22%]) showed a non-fatal pulmonary embolism during the three-month follow-up period after an initial negative CT scan (negative predictive value, 99.58%). Eleven patients died during the follow-up period due to conditions unrelated to venous thromboembolic disease (pneumonia [n=5], lung cancer [n=2], wasting syndrome [n=1], acute myocardial infarction [n=1], leiomyosarcoma [n=1], and severe pulmonary hypertension [n=1]).

CONCLUSIONS

Withholding anticoagulant therapy in patients with suspected venous thromboembolic disease with a negative result on MCTPA seems to be safe in our clinical setting.