Quantitative high D-dimer value is predictive of pulmonary embolism occurrence independently of clinical score in a well-defined low risk factor population

Construction of a coagulation prediction model of the extracorporeal circulation circuit during hemodialysis with regional citrate anticoagulant (RCA)

OBJECTIVE

To construct a prediction model of coagulation in the extracorporeal circulation circuit during hemodialysis with regional citrate anticoagulant(RCA) conditions.

METHODS

This was a single-center, retrospective study. The clinical data of patients who received hemodialysis with RCA from February 2021 to March 2022 were collected. The risk predictors of coagulation in the extracorporeal circulation circuit were screened by LASSO regression. On this basis, we used multivariate logistic regression analysis to establish a nomogram prediction model.

RESULTS

A total of 98 patients received RCA hemodialysis for 362 times. Among them, 155 treatments with complete data were included in the study. Among the 155 treatments, coagulation of the extracorporeal circulation circuit occurred 12 times. The use of arteriovenous fistulas(AVF), the venous pressure at 4 h after hemodialysis initiation, blood flow velocity, dialyzer manufacturer, Systemic iCa2+ at 1 h after hemodialysis initiation, plasma albumin level, and plasma d-dimer level were influencing factors of coagulation in the extracorporeal circuit during hemodialysis with RCA (p < 0.05). A nomogram model was made out of the above indicators. The area under the receiver operating characteristic (ROC) curve for predicting coagulation in the circuit was 0.967 (95% CI: 0.935-0.998). The internal validation result of the memory testing (bootstrap method) showed that the area under the ROC curve was 0.967 (95% CI: 0.918-0.991).

CONCLUSION

The nomogram model has good discrimination and calibration and can intuitively and succinctly predict the risk of coagulation in the extracorporeal circulation circuit during hemodialysis with RCA.

Optimal D-Dimer Cutoff Values for Diagnosing Deep Vein Thrombosis in Patients with Comorbid Malignancies

BACKGROUND

Patients with malignancy are at high risk of venous thromboembolism, and early diagnosis is important. The Khorana score is known as a risk assessment for cancer-related thrombosis during chemotherapy, but there are still few reports on its diagnostic potential, the optimal D-dimer cutoff values for indications other than chemotherapy and the use of the Khorana score in combination with D-dimers. In this study, we examined the clinical appropriateness of increasing the D-dimer cutoff value.

METHODS

We retrospectively studied 208 malignancies out of 556 patients who underwent lower extremity venous ultrasonography at our hospital over a 2-year period from January 2018 to December 2019. The optimal D-dimer cutoff value for predicting deep vein thrombosis (DVT) in patients with malignancy was calculated by the Youden index. The usefulness of the Khorana score alone and the model combining the Khorana score with D-dimer for predicting DVT diagnosis was compared using receiver operating characteristic analysis.

RESULTS

Of 208 eligible patients, 59 (28.4%) had confirmed DVT. The optimal D-dimer cutoff value for predicting DVT comorbidity in patients with malignancy was 3.96 μg/mL. When the new D-dimer cutoff value was set at 4.0 μg/mL, the odds ratio (OR) for DVT diagnosis was 4.23 (95% confidence interval (CI) 2.10-8.55, P < 0.001), which was higher than the OR of 1.33 (95% CI: 0.98-1.81, P = 0.064) for the Khorana score. The area under the curve for the Khorana score and D-dimer was 0.714, which was significantly higher than the 0.611 for the Khorana score alone, with the difference being significantly higher at 0.103 (P = 0.004, 95% CI: 0.033-0.173).

CONCLUSIONS

The optimal D-dimer cutoff value for the diagnosis of DVT in patients with malignancy was 4.0 μg/mL. It was also suggested that the combination of the Khorana score with the D-dimer level was more accurate in diagnosing DVT than the Khorana score alone.

Low diastolic blood pressure and adverse outcomes in inpatients with acute exacerbation of chronic obstructive pulmonary disease: A multicenter cohort study

BACKGROUND

Although intensively studied in patients with cardiovascular diseases (CVDs), the prognostic value of diastolic blood pressure (DBP) has little been elucidated in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). This study aimed to reveal the prognostic value of DBP in AECOPD patients.

METHODS

Inpatients with AECOPD were prospectively enrolled from 10 medical centers in China between September 2017 and July 2021. DBP was measured on admission. The primary outcome was all-cause in-hospital mortality; invasive mechanical ventilation and intensive care unit (ICU) admission were secondary outcomes. Least absolute shrinkage and selection operator (LASSO) and multivariable Cox regressions were used to identify independent prognostic factors and calculate the hazard ratio (HR) and 95% confidence interval (CI) for adverse outcomes.

RESULTS

Among 13,633 included patients with AECOPD, 197 (1.45%) died during their hospital stay. Multivariable Cox regression analysis showed that low DBP on admission (<70 mmHg) was associated with increased risk of in-hospital mortality (HR = 2.16, 95% CI: 1.53-3.05, Z = 4.37, P <0.01), invasive mechanical ventilation (HR = 1.65, 95% CI: 1.32-2.05, Z = 19.67, P <0.01), and ICU admission (HR = 1.45, 95% CI: 1.24-1.69, Z = 22.08, P <0.01) in the overall cohort. Similar findings were observed in subgroups with or without CVDs, except for invasive mechanical ventilation in the subgroup with CVDs. When DBP was further categorized in 5-mmHg increments from <50 mmHg to ≥100 mmHg, and 75 to <80 mmHg was taken as reference, HRs for in-hospital mortality increased almost linearly with decreased DBP in the overall cohort and subgroups of patients with CVDs; higher DBP was not associated with the risk of in-hospital mortality.

CONCLUSION

Low on-admission DBP, particularly <70 mmHg, was associated with an increased risk of adverse outcomes among inpatients with AECOPD, with or without CVDs, which may serve as a convenient predictor of poor prognosis in these patients.

CLINICAL TRIAL REGISTRATION

Chinese Clinical Trail Registry, No. ChiCTR2100044625.

Superior Predictive Value of D-Dimer to the Padua Prediction Score for Venous Thromboembolism in Inpatients with AECOPD: A Multicenter Cohort Study

Background

The optimal tool for risk prediction of venous thromboembolism (VTE) in inpatients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is still unknown. This study aimed to evaluate whether D-dimer could predict the risk of VTE in inpatients with AECOPD compared to the Padua Prediction Score (PPS).

Methods

Inpatients with AECOPD were prospectively enrolled from seven medical centers in China between December 2018 and June 2020. On admission, D-dimer was detected, PPS was calculated for each patient, and the incidence of 2-month VTE was investigated. The receiver operating characteristic (ROC) curve was used to evaluate the predictive value of D-dimer and PPS on VTE development, and the best cut-off value for both methods was evaluated through the Youden index.

Results

Among the 4468 eligible patients with AECOPD, 90 patients (2.01%) developed VTE within 2 months after admission. The area under the receiver operating characteristic curves (AUCs) of D-dimer for predicting VTE were significantly higher than those of the PPS both in the overall cohort (0.724, 95% CI 0.672–0.776 vs 0.620, 95% CI 0.562–0.679; P<0.05) and the subgroup of patients without thromboprophylaxis (0.747, 95% CI 0.695–0.799 vs 0.640, 95% CI 0.582–0.698; P<0.05). By calculating the Youden Index, the best cut-off value of D-dimer was determined to be 0.96 mg/L with an AUC of 0.689, which was also significantly better than that of the PPS with the best cut-off value of 2 (AUC 0.581, P=0.007). After the combination of D-dimer with PPS, the AUC (0.621) failed to surpass D-dimer alone (P=0.104).

Conclusion

D-dimer has a superior predictive value for VTE over PPS in inpatients with AECOPD, which might be a better choice to guide thromboprophylaxis in inpatients with AECOPD due to its effectiveness and convenience.

Clinical Trial Registration

Chinese Clinical Trail Registry NO. ChiCTR2100044625; URL: http://www.chictr.org.cn/showproj.aspx?proj=121626.

Complications in COVID-19 patients: Characteristics of pulmonary embolism

OBJECTIVE

The purpose of this study is to evaluate chest CT imaging features, clinical characteristics, laboratory values of COVID-19 patients who underwent CTA for suspected pulmonary embolism. We also examined whether clinical, laboratory or radiological characteristics could be associated with a higher rate of PE.

MATERIALS AND METHODS

This retrospective study included 84 consecutive patients with laboratory-confirmed SARS-CoV-2 who underwent CTA for suspected PE. The presence and localization of PE as well as the type and extent of pulmonary opacities on chest CT exams were examined and correlated with the information on comorbidities and laboratory values for all patients.

RESULTS

Of the 84 patients, pulmonary embolism was discovered in 24 patients. We observed that 87% of PE was found to be in lung parenchyma affected by COVID-19 pneumonia. Compared with no-PE patients, PE patients showed an overall greater lung involvement by consolidation (p = 0.02) and GGO (p < 0.01) and a higher level of D-Dimer (p < 0,01). Moreover, the PE group showed a lower level of saturation (p = 0,01) and required more hospitalization (p < 0,01).

CONCLUSION

Our study showed a high incidence of PE in COVID-19 pneumonia. In 87% of patients, PE was found in lung parenchyma affected by COVID-19 pneumonia with a worse CT severity score and a greater number of lung lobar involvement compared with non-PE patients. CT severity, lower level of saturation, and a rise in D-dimer levels could be an indication for a CTPA.

ADVANCES IN KNOWLEDGE

Certain findings of non-contrast chest CT could be an indication for a CTPA.

Diagnostic performance of D-dimer in predicting venous thromboembolism and acute aortic dissection

BACKGROUND

D-dimer is elevated in a variety of conditions. The purpose of this study was to assess the positive predictive value of D-dimer to rule in patients with confirmed pulmonary embolism, deep vein thrombosis, acute aortic dissection or thrombosis of the upper extremity in comparison to patients with elevated D-dimer for other reasons.

METHODS AND RESULTS

We studied 1334 patients presenting to the emergency department with pulmonary embolism (n=193), deep vein thrombosis (n=73), acute aortic dissection (n=22), thrombosis of the upper extremity (n=8) and 1038 controls. The positive predictive value was increased with higher D-dimer concentrations improving the ability to identify diseases with high thrombus burden. Patients with venous thromboembolism, acute aortic dissection and thrombosis of the upper extremity showed a maximum positive predictive value of 85.2% at a D-dimer level of 7.8 mg/L (95% confidence interval (CI) 78.1 to 90.4). The maximum positive predictive value was lower in cancer patients with venous thromboembolism, acute aortic dissection and thrombosis of the upper extremity, reaching 68.9% at a D-dimer level of 7.5 mg/L (95% CI 57.4 to 78.4). The positive likelihood ratio was very consistent with the positive predictive value. Using a cut-off level of 0.5 mg/L, D-dimer showed a high sensitivity of at least 93%, but a very low specificity of nearly 0%. Conversely, an optimised cut-off value of 4.6 mg/L increased specificity to 95% for the detection of life-threatening venous thromboembolism, acute aortic dissection or thrombosis of the upper extremity at the costs of moderate sensitivities (58% for pulmonary embolism, 41% for deep vein thrombosis, 65% for pulmonary embolism with co-existent deep vein thrombosis, 50% for acute aortic dissection and 13% for thrombosis of the upper extremity). Using the same cut-off in cancer patients, higher values were observed for sensitivity at a specificity level of more than 95%. The area under the curve for the discrimination of venous thromboembolism/acute aortic dissection/thrombosis of the upper extremity from controls was significantly higher in cancer versus non-cancer patients (area under the curve 0.905 in cancer patients, 95% CI 0.89 to 0.92, vs. area under the curve 0.857 in non-cancer patients, 95% CI 0.84 to 0.88; P=0.0349).

CONCLUSION

D-dimers are useful not only to rule out but also to rule in venous thromboembolism and acute aortic dissection with an at least moderate discriminatory ability, both in patients with and without cancer.

Systematic review and meta-analysis of test accuracy for the diagnosis of suspected pulmonary embolism

Pulmonary embolism (PE) is a common, potentially life-threatening yet treatable condition. Prompt diagnosis and expeditious therapeutic intervention is of paramount importance for optimal patient management. Our objective was to systematically review the accuracy of D-dimer assay, compression ultrasonography (CUS), computed tomography pulmonary angiography (CTPA), and ventilation-perfusion (V/Q) scanning for the diagnosis of suspected first and recurrent PE. We searched Cochrane Central, MEDLINE, and EMBASE for eligible studies, reference lists of relevant reviews, registered trials, and relevant conference proceedings. 2 investigators screened and abstracted data. Risk of bias was assessed using Quality Assessment of Diagnostic Accuracy Studies-2 and certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation framework. We pooled estimates of sensitivity and specificity. The review included 61 studies. The pooled estimates for D-dimer sensitivity and specificity were 0.97 (95% confidence interval [CI], 0.96-0.98) and 0.41 (95% CI, 0.36-0.46) respectively, whereas CTPA sensitivity and specificity were 0.94 (95% CI, 0.89-0.97) and 0.98 (95% CI, 0.97-0.99), respectively, and CUS sensitivity and specificity were 0.49 (95% CI, 0.31-0.66) and 0.96 (95% CI, 0.95-0.98), respectively. Three variations of pooled estimates for sensitivity and specificity of V/Q scan were carried out, based on interpretation of test results. D-dimer had the highest sensitivity when compared with imaging. CTPA and V/Q scans (high probability scan as a positive and low/non-diagnostic/normal scan as negative) both had the highest specificity. This systematic review was registered on PROSPERO as CRD42018084669.

CT imaging of pulmonary embolism in patients with COVID-19 pneumonia: a retrospective analysis

Objectives

To describe imaging and laboratory findings of confirmed PE diagnosed in COVID-19 patients and to evaluate the characteristics of COVID-19 patients with clinical PE suspicion. Characteristics of patients with COVID-19 and PE suspicion who required admission to the intensive care unit (ICU) were also analysed.

Methods

A retrospective study from March 18, 2020, until April 11, 2020. Inclusion criteria were patients with suspected PE and positive real-time reverse-transcription polymerase chain reaction (RT-PCR) for SARS-CoV-2. Exclusion criteria were negative or inconclusive RT-PCR and other chest CT indications. CTPA features were evaluated and severity scores, presence, and localisation of PE were reported. d-dimer and IL-6 determinations, ICU admission, and previous antithrombotic treatment were registered.

Results

Forty-seven PE suspicions with confirmed COVID-19 underwent CTPA. Sixteen patients were diagnosed with PE with a predominant segmental distribution. Statistically significant differences were found in the highest d-dimer determination in patients with PE and ICU admission regarding elevated IL-6 values.

Conclusion

PE in COVID-19 patients in our series might predominantly affect segmental arteries and the right lung. Results suggest that the higher the d-dimer concentration, the greater the likelihood of PE. Both assumptions should be assessed in future studies with a larger sample size.

Key Points

• On CT pulmonary angiography, pulmonary embolism in COVID-19 patients seems to be predominantly distributed in segmental arteries of the right lung, an assumption that needs to be approached in future research.

• Only the highest intraindividual determination ofd-dimer from admission to CT scan seems to differentiate patients with pulmonary embolism from patients with a negative CTPA. However, interindividual variability calls for future studies to establish cut-off values in COVID-19 patients.

• Further studies with larger sample sizes are needed to determine whether the presence of PE could increase the risk of intensive care unit (ICU) admission in COVID-19 patients.

Incidence and risk factors of preoperative venous thromboembolism and pulmonary embolism in patients with ovarian cancer

INTRODUCTION

To determine the incidence and predisposing factors of preoperative venous thromboembolism (VTE), especially pulmonary embolism (PE) in patients with ovarian cancer.

MATERIAL AND METHODS

This retrospective study included 387 patients with primary ovarian cancer, whose preoperative work up included both ultrasonography of lower extremity vein and spiral computed tomography pulmonary angiogram, from September 2013 to November 2016. SPSS 22 was used for statistical analyses.

RESULTS

The incidence of preoperative VTE and PE was 13.4% (52 patients), 9.3%(36 patients), respectively. Both the univariate and multivariate analyses revealed that D-dimer (DDI) level, age, and massive ascites were associated with preoperative VTE. Moreover, DDI level (odds ratio [OR] 3.133, 95% confidence interval [CI] 1.193-8.225, p = .02), massive ascites (OR 9.972, 95% CI 3.687-26.968, p < .001), and preoperative deep vein thrombosis (OR 5.977, 95% CI 2.073-17.228, p = .001) were independent predictors for preoperative PE. Additionally, the incidence of preoperative VTE and PE increased with increasing DDI levels (p < .001). DDI level < 1.5 μg/ml has 100% negative predictive value and 100% sensitivity for diagnosis of preoperative VTE and PE; however, DDI >5 μg/ml, the incidence of preoperative VTE and PE were 18.4% and 14.2% respectively. Moreover, DDI value was significantly correlated with preoperative PE volume (r = 0.746, p < .001).

CONCLUSION

Preoperative VTE and PE are common events in patients with ovarian cancer. DDI level is a useful parameter for diagnosing and evaluating preoperative VTE and PE.

American Society of Hematology 2018 guidelines for management of venous thromboembolism: diagnosis of venous thromboembolism

BACKGROUND

Modern diagnostic strategies for venous thromboembolism (VTE) incorporate pretest probability (PTP; prevalence) assessment. The ability of diagnostic tests to correctly identify or exclude VTE is influenced by VTE prevalence and test accuracy characteristics.

OBJECTIVE

These evidence-based guidelines are intended to support patients, clinicians, and health care professionals in VTE diagnosis. Diagnostic strategies were evaluated for pulmonary embolism (PE), deep vein thrombosis (DVT) of the lower and upper extremity, and recurrent VTE.

METHODS

The American Society of Hematology (ASH) formed a multidisciplinary panel including patient representatives. The McMaster University GRADE Centre completed systematic reviews up to 1 October 2017. The panel prioritized questions and outcomes and used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess evidence and make recommendations. Test accuracy estimates and VTE population prevalence were used to model expected outcomes in diagnostic pathways. Where modeling was not feasible, management and accuracy studies were used to formulate recommendations.

RESULTS

Ten recommendations are presented, by PTP for patients with suspected PE and lower extremity DVT, and for recurrent VTE and upper extremity DVT.

CONCLUSIONS

For patients at low (unlikely) VTE risk, using D-dimer as the initial test reduces the need for diagnostic imaging. For patients at high (likely) VTE risk, imaging is warranted. For PE diagnosis, ventilation-perfusion scanning and computed tomography pulmonary angiography are the most validated tests, whereas lower or upper extremity DVT diagnosis uses ultrasonography. Research is needed on new diagnostic modalities and to validate clinical decision rules for patients with suspected recurrent VTE.

Doppler ultrasound and D-dimer

The diagnosis of venous thromboembolism has evolved considerably with the development of standardized diagnostic algorithms that include clinical probability assessment, D-dimer measurement and the use of non-invasive imaging modalities such as compression ultrasonography and computed tomography angiography. The implementation of these strategies aims to improve resource allocation and patient outcome. The judicious use of these diagnostic tools requires a thorough knowledge of the appropriate clinical setting in which every test and strategy is efficient and can be used safely. For this purpose, D-dimer measurement and compression ultrasonography are complementary: the former is mainly used to exclude VTE in selected patients, while the latter is used to confirm the presence of an underlying DVT.

This review provides an appraisal of the features and use of D-dimer and compression ultrasonography in the context of suspected venous thromboembolism.

D-Dimer Use and Pulmonary Embolism Diagnosis in Emergency Units: Why Is There Such a Difference in Pulmonary Embolism Prevalence between the United States of America and Countries Outside USA?

OBJECTIVE

Although diagnostic guidelines are similar, there is a huge difference in pulmonary embolism (PE) prevalence between the United States of America (US) and countries outside the USA (OUS) in the emergency care setting. In this study, we prospectively analyze patients' characteristics and differences in clinical care that may influence PE prevalence in different countries.

METHODS

An international multicenter prospective diagnostic study was conducted in a standard-of-care setting. Consecutive outpatients presenting to the emergency unit and suspected for PE were managed using the Wells score, STA-Liatest® D-Dimers and imaging.

RESULTS

The prevalence of PE in the study was 7.9% in low and moderate risk patients. Among the 1060 patients with low or moderate pre-test probability (PTP), PE prevalence was four times higher in OUS (10.7%) than in the US (2.5%) (P < 0.0001). The mean number of imaging procedures performed for one new PE diagnosis was 3.3 in OUS vs 17 in the US (P < 0.001). Stopping investigation in the case of negative D-dimers (DD combined) with low/moderate PTP was more frequent in OUS (92.7%) than in the US (75.7%) (P < 0.01). Moreover, the use of imaging was much higher in the US (44.4% vs 19.2% in OUS) in the case of moderate PTP combined with negative DD.

CONCLUSION

Differences between US and OUS PE prevalence in emergency setting might be explained by differences in patients' characteristics and mostly in care patterns. US physicians performed computed tomographic pulmonary angiography more often than in Europe in cases of low/moderate PTP combined with negative DD.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01221805.

Role of D-dimer Assays in the Diagnostic Evaluation of Pulmonary Embolism

The diagnosis of pulmonary embolism (PE) remains challenging despite the evolution of well-validated clinical algorithms over the past few decades, largely because of nonspecific clinical features altering clinician suspicion. D-dimer is a simple noninvasive test that is an essential part of the diagnostic algorithm but is often deemed to be of little value in patients who are elderly or have other comorbidities. We describe a case of an elderly man who presented with clinical features and initial imaging consistent with pneumonia and a positive D-dimer test. Adherence to the suggested diagnostic algorithm and obtaining chest imaging, however, prevented what could have been a catastrophic missed diagnosis of PE. We review existing evidence on the importance of suspecting PE in the presence of alternative diagnosis and explore the literature on the association between the magnitude of D-dimer and the diagnosis of PE.

Effectiveness of d-dimer as a screening test for venous thromboembolism: an update

Venous thromboembolism (VTE) is the leading cause of morbidity and mortality among hospitalized patients. We searched the PubMed database and reviewed the articles published until June 2011. Articles related to the D-dimer and VTE were considered to write this paper. Many factors play a key role in changing the sensitivity and specificity of D-dimer testing, including the extent of thrombosis and fibrinolytic activity, duration of symptoms, anticoagulant therapy, comorbidity due to surgical or medical illnesses, inflammatory diseases, cancer, elderly age, pregnancy and the postpartum period, and previous VTE. Many previous studies have shown that the D-dimer test is highly sensitive (>95%) in acute deep venous thrombosis or pulmonary embolism, usually with a cut-off value of 500 μg FEU/l, which reasonably rules out acute VTE, particularly in patients with low clinical probability (LCP) or intermediate clinical probability. Patients with high D-dimer levels upon presentation may prompt a more intense diagnostic approach, irrespective of pretest probability. Studies performed after a negative D-dimer for 3 months proved the high negative predictive value (NPV) of D-dimer testing together with LCP in patients with suspected VTE. Among oncology patients, D-dimer testing has the highest sensitivity and NPV in excluding VTE. The new cutoff values of D-dimer testing were analyzed in a recent prospective study of pregnant women; they are 286 ng DDU/ml, 457 ng DDU/ml, and 644 ng DDU/ml for the first, second, and third trimesters, respectively.

Magnitude of D-dimer matters for diagnosing pulmonary embolus

OBJECTIVE

The objective of this study is to determine whether the magnitude of the D-dimer correlates with a higher likelihood of pulmonary embolus (PE).

METHODS

We performed an electronic chart review at our academic, tertiary care center, annual emergency department (ED) census greater than 100000. All patients with a chest computed tomographic (CT) scan with intravenous contrast and an elevated D-dimer level obtained in the ED between January 2001 and July 2008 were identified. Specific, predetermined, predefined data elements including sex, age, D-dimer level, and final ED diagnosis were recorded by a hypothesis-blinded extractor using a preformatted data form. D-dimer level less than 0.58 μg/mL constitutes the normal laboratory reference range for our turbidometric D-dimer assay. Data were analyzed using standard statistical methods, and a linear regression analysis was performed for correlation analysis of D-dimer and diagnosis of PE.

RESULTS

We identified 544 subjects who had both a chest CT scan performed and an elevated D-dimer level obtained in the ED. Fifty-eight subjects (10.7%; mean D-dimer, 4.9 μg/mL) were diagnosed with PE, and 486 (89.3%; mean D-dimer, 2.0) did not have a PE. The percentages of PE diagnoses for D-dimers in the ranges 0.58 to 1.0, 1.0 to 2.0, 2.0 to 5.0, 5.0 to 20.0, and greater than 20.0 (n = 11) were 3.6%, 8.0%, 16.2%, 35.3%, and 45.5%, respectively. The positive predictive value of PE for D-dimer level cutoffs of greater than 0.58, greater than 1.0, greater than 2.0, greater than 5.0, and greater than 20.0 was 10.7%, 14.6%, 22.2%, 37.8%, and 45.5%, respectively. Increasing D-dimer values were strongly correlated with the presence of PE (odds ratio, 1.1685 per stratum; P < .001).

CONCLUSION

Increasing magnitude of D-dimer correlates with increasing likelihood of PE diagnosed by CT angiography.

A model for calculating the within-subject biological variation and likelihood ratios for analytes with a time-dependent change in concentrations; exemplified with the use of D-dimer in suspected venous thromboembolism in healthy pregnant women

BACKGROUND

Within-subject biological variation and reference change value (RCV) are difficult to calculate for an analyte with a changing concentration. The aim of this study was to develop a model to examine if it was possible to transform an analyte with a time-dependent change in concentration into a 'steady-state' situation by the use of 'multiples of the median' (MoM) and its natural logarithm (lnMoM). In addition, we wanted to extend the RCV concept, using likelihood and odds ratios, to calculate the post-test probabilities for disease. D-dimer in pregnancy is used as an example.

METHODS

Blood samples from 18 healthy pregnant and 18 healthy non-pregnant women were collected every fourth week. MoM of the D-dimer concentrations was calculated for each four-week interval to obtain a 'steady-state' situation for the D-dimer concentrations. The 'normalized' values were then transformed to the lnMoM to obtain a Gaussian distribution, used for the estimation of biological variation.

RESULTS

Median D-dimer concentrations increased six-fold during pregnancy. Within-subject variation (SD) of lnMoM D-dimer was 0.27 during pregnancy and 0.23 in non-pregnant women, with RCVs of 0.72 and 0.90, respectively.

CONCLUSIONS

By using the lnMoM model, an increasing concentration of an analyte can be transformed to a steady-state situation and the within-subject biological variation and its derived parameters can be calculated.

Diagnosis of venous thromboembolism: an update

Deep vein thrombosis (DVT) and pulmonary embolism (PE) cannot be diagnosed solely on a clinical basis owing to the lack of sensitivity and specificity of clinical signs and symptoms. Phlebography and pulmonary angiography are invasive and resource-demanding imaging modalities. Because the prevalence of DVT and PE is relatively low (typically 20% or less) among clinically suspected individuals, submitting all of them to imaging would not be cost-effective. Therefore, non-invasive diagnostic algorithms have been developed that include clinical probability assessment and D-dimer measurement. These initial steps allow the selection of patients who require non-invasive imaging: compression ultrasonography in cases of suspected DVT and multidetector computed tomography (CT) angiography in cases of suspected PE. This review gives a critical appraisal of the sequential steps of the diagnostic work-up in suspected DVT or PE.

Contemporary management of pulmonary embolism: the answers to ten questions

Pulmonary embolism (PE) cannot be diagnosed solely on a clinical basis, because of the lack of sensitivity and specificity of clinical signs and symptoms. Pulmonary angiography is invasive and resource demanding. Because the prevalence of PE is relatively low (20% or less) amongst individuals who are clinically suspected of having the disease, submitting all of them to imaging (multi-detector CT angiography or ventilation/perfusion lung scintigraphy) would not be cost-effective. Therefore, diagnostic algorithms have been developed that include clinical probability assessment and D-dimer measurement to select the patients who require noninvasive imaging. Once the diagnosis is suspected or confirmed, therapy must be started to avoid potentially fatal recurrence. Treatment starts for an initial 3-month period with a 5-day course of parenteral unfractionated or low-molecular-weight heparin or fondaparinux overlapping with and followed by oral vitamin K antagonists monitored to maintain an international normalized ratio of 2-3. This initial period of 3 months may then be followed by a long-term secondary prevention period in patients who experience an idiopathic thromboembolic event and are at low risk of bleeding. New oral anticoagulants that do require patient monitoring and might exhibit a more favourable benefit-risk balance are currently under extensive clinical testing and might change the situation in the near future. A critical appraisal of the contemporary management of suspected PE is given in this overview with the discussion of 10 practical questions.

Acute pulmonary embolism. Part 1: epidemiology and diagnosis

Pulmonary embolism (PE) is a frequently occurring, acute, and potentially fatal condition. Numerous risk factors for PE, both inherited and acquired, have been identified. Adequate diagnosis is mandatory to prevent PE-related morbidity and mortality on the one hand, and unnecessary treatment on the other. Only around 1 in 5 individuals with suspected PE will have the diagnosis confirmed, therefore, the diagnostic work-up for PE should comprise safe, efficient, and noninvasive methods. The first step in the approach to diagnosis of patients with suspected PE is to determine the clinical probability and to perform a D-dimer test. PE can be excluded in patients with a 'low', 'intermediate' or 'unlikely' clinical probability and a normal D-dimer test. Additional imaging is required for those with a 'high' or 'likely' clinical probability or a positive D-dimer test. CT pulmonary angiography or ventilation-perfusion scintigraphy, followed by additional testing is the next step when test results are nondiagnostic. Although various diagnostic strategies have been introduced and validated, selected patients may require a tailored approach.

Clinical prediction rules for pulmonary embolism: a systematic review and meta-analysis

SUMMARY BACKGROUND

Pretest probability assessment is necessary to identify patients in whom pulmonary embolism (PE) can be safely ruled out by a negative D-dimer without further investigations.

OBJECTIVE

Review and compare the performance of available clinical prediction rules (CPRs) for PE probability assessment.

PATIENTS/METHODS

We identified studies that evaluated a CPR in patients with suspected PE from Embase, Medline and the Cochrane database. We determined the 95% confidence intervals (CIs) of prevalence of PE in the various clinical probability categories of each CPR. Statistical heterogeneity was tested.

RESULTS

We identified 9 CPR and included 29 studies representing 31215 patients. Pooled prevalence of PE for three-level scores (low, intermediate or high clinical probability) was: low, 6% (95% CI, 4-8), intermediate, 23% (95% CI, 18-28) and high, 49% (95% CI, 43-56) for the Wells score; low, 13% (95% CI, 8-19), intermediate, 35% (95% CI, 31-38) and high, 71% (95% CI, 50-89) for the Geneva score; low, 9% (95% CI, 8-11), intermediate, 26% (95% CI, 24-28) and high, 76% (95% CI, 69-82) for the revised Geneva score. Pooled prevalence for two-level scores (PE likely or PE unlikely) was 8% (95% CI,6-11) and 34% (95% CI,29-40) for the Wells score, and 6% (95% CI, 3-9) and 23% (95% CI, 11-36) for the Charlotte rule.

CONCLUSION

Available CPR for assessing clinical probability of PE show similar accuracy. Existing scores are, however, not equivalent and the choice among various prediction rules and classification schemes (three- versus two-level) must be guided by local prevalence of PE, type of patients considered (outpatients or inpatients) and type of D-dimer assay applied.

Prospective diagnostic accuracy assessment of the HemosIL HS D-dimer to exclude pulmonary embolism in emergency department patients

INTRODUCTION

Chest pain and shortness of breath are among the most common symptoms requiring immediate evaluation. Testing for pulmonary embolism (PE) has become easier and widespread due to D-dimer blood tests. Safe use of these tests is only possible if sensitivity is high and they are used in non-high probability patients. We evaluated diagnostic performance of the HemosIL HS D-dimer, which despite FDA approval in 2005, has been minimally reported in prospective standard clinical care.

MATERIALS AND METHODS

We used a prospective observational study design to follow patients in a single center with the HemosIL HS ordered for symptoms of possible PE with positive test result if >243 ng/ml. The outcome was PE or deep venous thrombosis (DVT) at the time of presentation or subsequent 45 days determined by structured evaluation of imaging tests, phone, or medical record follow-up in all patients.

RESULTS

529 patients received a D-dimer and 4.7% were ultimately diagnosed with PE or DVT. The sensitivity of the HemosIL HS was 96.0% (95% CI; 79.6 to 99.9%) specificity was 65.7% (95% CI; 61.4 to 69.8%) and likelihood ratio negative was 0.06 (95% CI; 0.01 to 0.42). The probability of PE in patients with a negative D-dimer was 1/332 or 0.3% (95% CI; 0.01% to 1.67%). The receiver operator curve had an area under the curve of 0.87 and supported the current cut-point as optimal.

CONCLUSIONS

The HemosIL HS D-dimer had high sensitivity, very low negative post-test probability and is useful in excluding PE in the acute care setting.

High D-dimer levels increase the likelihood of pulmonary embolism

Objective. To determine the utility of high quantitative D-dimer levels in the diagnosis of pulmonary embolism. Methods. D-dimer testing was performed in consecutive patients with suspected pulmonary embolism. We included patients with suspected pulmonary embolism with a high risk for venous thromboembolism, i.e. hospitalized patients, patients older than 80 years, with malignancy or previous surgery. Presence of pulmonary embolism was based on a diagnostic management strategy using a clinical decision rule (CDR), D-dimer testing and computed tomography. Results. A total of 1515 patients were included with an overall pulmonary embolism prevalence of 21%. The pulmonary embolism prevalence was strongly associated with the height of the D-dimer level, and increased fourfold with D-dimer levels greater than 4000 ng mL(-1) compared to levels between 500 and 1000 ng mL(-1). Patients with D-dimer levels higher than 2000 ng mL(-1) and an unlikely CDR had a pulmonary embolism prevalence of 36%. This prevalence is comparable to the pulmonary embolism likely CDR group. When D-dimer levels were above 4000 ng mL(-1), the observed pulmonary embolism prevalence was very high, independent of CDR score. Conclusion. Strongly elevated D-dimer levels substantially increase the likelihood of pulmonary embolism. Whether this should translate into more intensive diagnostic and therapeutic measures in patients with high D-dimer levels irrespective of CDR remains to be studied.

D-dimer testing is useful to exclude deep vein thrombosis in elderly outpatients

BACKGROUND

Deep vein thrombosis (DVT) can be safely and reliably excluded in patients with a low clinical probability and a negative D-dimer result but the accuracy and utility of such a strategy is unclear in elderly patients.

OBJECTIVES

We sought to compare the performance of the Wells pretest probability (PTP) model and D-dimer testing between patients of different age groups and to examine the utility of the two PTP model classification schemes (low/moderate/high vs. unlikely/likely) in excluding DVT in elderly outpatients.

PATIENTS/METHODS

Pooled analysis of databases from three prospective diagnostic studies evaluating consecutive outpatients with suspected DVT.

RESULTS

A total of 2696 patients were evaluated. DVT was diagnosed in 400 (15%) patients overall and in 50 out of 325 (15.5%) patients > or = 60 years old. The PTP distribution and the prevalence of DVT in each PTP category were similar among the different age groups. The negative predictive values of a low or unlikely PTP score in combination with a negative D-dimer result were 99% for all groups. A negative D-dimer in combination with a low or unlikely PTP excluded 21.7% and 31% of patients > or = 80 years old, respectively.

CONCLUSIONS

The combination of a low or unlikely PTP with a negative D-dimer result can effectively and safely exclude DVT in a significant proportion of elderly outpatients. However, this clinical prediction rule needs to be prospectively validated with different D-dimer assays in this specific population.

Advances in the detection of pulmonary embolism

BACKGROUND

Diagnosing or excluding pulmonary embolism is a complex challenge. Many diagnostic instruments can be used in patients with clinically suspected pulmonary embolism nowadays, all with their own (dis-)advantages. Methods/objectives: In this review, these (dis-)advantages are discussed for the following diagnostic instruments: clinical probability assessment, D-dimer concentration, the combination of clinical probability assessment and D-dimer concentration, bilateral compression ultrasonography, ventilation/perfusion scintigraphy, computerized tomographic pulmonary angiography, pulmonary angiography and magnetic resonance pulmonary angiography. A diagnostic strategy, which can be adjusted to local facilities, is provided and discussed.

CONCLUSION

Using combinations of some of these diagnostic tools, many diagnostic strategies are possible and every hospital should make its own local protocol suited for the local situation.

Uses of different D-dimer levels can reduce the need for venous duplex scanning to rule out deep vein thrombosis in patients with symptomatic pulmonary embolism

OBJECTIVE

This study investigated the prevalence and distribution of deep vein thrombosis (DVT) in patients with symptomatic pulmonary embolism (PE) to establish a screening protocol to reduce unnecessary venous duplex scanning using different D-dimer level rather than single cutoff point of 0.5 microg/mL in patients with low and moderate pretest clinical probability (PTP).

METHODS

The PTP score and D-dimer testing were used to evaluate 85 consecutive patients with symptomatically proven PE before venous duplex scanning. After calculating the PTP score, patients were divided into low (<or=0 points), moderate (1 to 2 points), and high (>or=3 points) PTP groups. The receiver operating characteristic (ROC) curves analysis was used to determine the appropriate D-dimer cutoff point in low and moderate PTP, with a negative predictive value of >98%.

RESULTS

The study enrolled 81 patients. The prevalence of DVT was 63%, with 27 patients (33%) classified as low, 38 (47%) as moderate, and 16 (20%) as high PTP. DVT was detected in nine patients (33%) in the low PTP group, in 27 (71%) in the moderate group, and in 15 (94%) in the high group. In the low PTP patients, the difference in the value of D-dimer assay between positive-scan and negative-scan patients was statistically significant (9.99 +/- 7.33 vs 3.46 +/- 4.20, respectively; P = .008). Conversely, no significant difference in the D-dimer assay value between positive and negative scan results was found in the moderate PTP patients. ROC curves analysis were used to select D-dimer cutoff points of 2.0 microg/mL for the low PTP group and 0.7 microg/mL for the moderate PTP groups. For both groups, D-dimer testing provided 100% sensitivity and 100% negative predictive value in the diagnosis of DVT. In the low PTP group, specificity increased from 33% to 67% (P = .046). In the moderate PTP group, however, the determined D-dimer level did not improve the specificity. Overall, venous duplex scanning could have been reduced by 17% (14/81) by using different D-dimer cutoff points.

CONCLUSIONS

A combination of specific D-dimer level and clinical probability score is most effective in the low PTP patients in excluding DVT. In the moderate PTP group, however, the recommended cutoff point of 0.5 microg/mL may be preferable. These results show that a different D-dimer level is more useful than single cutoff point of 0.5 microg/mL in excluding DVT in established PE patients.

Integrated strategies for the diagnosis of venous thromboembolism

Diagnosis of deep vein thrombosis (DVT) and pulmonary embolism (PE) is an important medical problem because of the high fatality rate from PE and the large number of cases not diagnosed before causing death. Over the last decade, there has been considerable research into the diagnostic process. It is widely accepted that venous ultrasound imaging is an accurate test for the diagnosis of DVT and is the imaging test of choice. For PE, computer tomographic pulmonary angiography (CTPA) is replacing ventilation perfusion lung scanning. Technology for CTPA is rapidly evolving and multi-row detector scans have quite reasonable sensitivity and specificity. Despite the accuracy of imaging tests, the post-test probability of disease is highly dependent on pretest probability. Clinical evaluation tools have developed that enable us to accurately categorize patients' risk prior to diagnostic imaging. One advantage of this characterization is an ability to exclude the diagnosis of DVT or PE if clinical probability is sufficiently low and when the D-dimer is negative. There are now a number of D-dimer assays that have well-defined specificities and sensitivities, which enable use in conjunction with clinical probability. A careful combination of clinical assessment, D-dimer and imaging enables safe PE rule out protocols without imaging, an ability to suspect false positive imaging results, and more accurate determination of true positive imaging. These integration strategies result in safer, more convenient and cost-effective care for patients.

Electrocardiography and Wells scoring in predicting the anatomic severity of pulmonary embolism

Pulmonary embolism (PE) is a major health problem associated with a significant morbidity and mortality. Immediate recognition of submassive and massive cases is extremely important in order to commencement of early and appropriate therapy that could be life saving. The aim of this study was to assess the ability of two scoring systems, electrocardiography (ECG) and simplified Wells (sWells) clinical scorings in predicting anatomic severity of PE. Hence, ECG and sWells scorings were combined in order to test the hypothesis if this new scoring does enhance the prediction of severity. Fifty six patients with proven PE with high (50 patients) and moderate (six patients)-probability of ventilation/perfusion (V/Q) scan were retrospectively studied. Baseline ECGs were analysed by two independent observers in order to constitute ECG scorings. Baseline sWells scores were also calculated. Anatomic severity of PE was calculated by scintigraphically and categorized into mild (<50% perfusion defect) (group 1), and severe (50% perfusion defect) (group 2) diseases. The mean of ECG scores, sWells scores and the combined scores were 5.23+/-3.42 and 5.85+/-3.82; 6.60+/-1.88 and 7.03+/-2.40; and 10.73+/-3.60 and 11.60+/-4.32 in groups 1 and 2, respectively (p>0.05). An ECG score of 6.5 predicted severe disease (perfusion defect 50%) with a sensitivity of 41.7% and a specificity of 82%). sWells and combined scores did not provide better sensitivity or specificity values based on ROC curve analysis. Our results indicated that ECG scoring could be valuable test in predicting anatomic severity of PE, adding sWells scoring to ECG scoring did not provide any beneficial effect.

Non-conform diagnostic management of pulmonary embolism suspected patients is responsible for a higher risk of thrombotic event occurrence

The aim of this 3-month follow-up prospective pragmatic study was to evaluate the implementation of a pulmonary embolism (PE) diagnostic strategy in clinical practice. One thousand and one hundred thirty-four consecutive in- and outpatients with clinically suspected PE were enrolled into a sequential diagnostic algorithm in which vascular medical unit plays a pivotal role in advising physicians and suggesting the most appropriate tests according to the diagnostic algorithm. In this observational study, patients that followed the proposed work-up were attributed to a so-called "conform group". Patients in whom diagnostic work-up was not according to protocol were attributed to a "non-conform group". Nine hundred and ninety-seven patients (87.9%) had a conform work-up, and 137 patients a non-conform work-up according to the proposed diagnostic algorithm. The non-conform work-up directly increased in relation to the age of the referred patients. PE was ruled out in 907 (80%) patients of whom 787 (86.8%) were in the conform group. Of the 797 patients who did not receive anticoagulant drugs, follow-up was obtained in 792 (99.4%). Among these patients, the incidence of acute thromboembolic events during the 3-month follow-up period was different in the group of patients that had a conform work-up (1%, [95% CI, 0.5-2.1%]) from the non-conform group patients (4.5%, [95% CI, 2-10.2%]. Therefore patients from the non-conform group have an independent increased risk to develop a thromboembolic event during the follow-up, adjusted odds ratio 3.3 [1.1-10, 95% CI]. Therefore we demonstrated that a non-conform diagnostic management strategy is associated with a higher risk of thrombotic event occurrence.

Diagnosis of pulmonary embolism: in transition

PURPOSE OF REVIEW

To discuss reports published in 2005 on the diagnosis of clinically suspected nonmassive pulmonary embolism.

RECENT FINDINGS

Progress has been made in assessing the clinical probability of pulmonary embolism, in addressing diagnosis in the elderly, in evaluating the diagnostic performance of single-detector and multidetector row helical computed tomography, and in the role of D-dimer measurement and lower limb venous compression ultrasonography in the diagnostic work-up of pulmonary embolism.

SUMMARY

Diagnosing venous thromboembolism depends mainly on noninvasive diagnostic tools that are used sequentially. In most patients, a noninvasive work-up is feasible and the diagnostic algorithms are becoming simpler. This review focuses on developments in clinical probability assessment, pulmonary embolism in the elderly, potential new uses of D-dimer measurement, advent of multidetector row helical computed tomography, and utility of ultrasonography in detecting deep vein thrombosis in patients with suspected pulmonary embolism. With the development of potentially more sensitive diagnostic tests for pulmonary embolism, physicians are now facing the risk of overdiagnosis and hence overtreatment. The issue will no longer be just to detect clots but to identify patients who must be treated using anticoagulants, a complicated question.

D-dimer level is associated with the extent of pulmonary embolism

OBJECTIVES

Our aim was to study the association between the level of D-dimer and the severity of pulmonary embolism (PE) as determined by various biochemical and radiological prognostic markers in order to investigate the potential value of D-dimer as a prognostic marker for the severity of PE.

PATIENTS AND METHODS

PE was diagnosed in 100 consecutive out-patients by multi-detector computerized tomography. One patient was excluded and the final cohort consisted of 99 patients. Pulmonary Artery Obstruction Index (PAOI) and Right Ventricular/Left Ventricular (RV/LV) ratio were assessed.

RESULTS

The median value for D-dimer was 5.0 mg/L (inter-quartile range: 1.8, 12.2). There was a significant association between log D-dimer, and between log RV/LV (r=0.45), log PAOI (r=0.5), and PaO(2) (r=0.40). The multivariate analysis showed an increased association between log D-dimer and between log RV/LV ratio (r=0.54) and log PAOI (r=0.52) after adjusting for age, gender and for the duration of symptoms. Significant association was found between the level of D-dimer and the most proximal level of PE (p<0.0005). There was a significant dose-response relationship between the level D-dimer and between Troponin-T and the frequency of thrombolysis (p<0.0005). In the subgroup of patients with D-Dimer over the upper quartile (>12.2), 12 (67%) patients had elevated Troponin-T and 8 (32%) patients received thrombolysis, compared to 1 (5%) patient with elevated Troponin-T and none treated with thrombolysis in the subgroup of patients with D-dimer<lower quartile.

CONCLUSIONS

We have shown that the level of D-dimer is related to the severity of PE assessed by various radiological, biochemical and clinical markers and might have a potential value as prognostic marker for the severity of PE.

High D-dimer levels at presentation in patients with venous thromboembolism is a marker of adverse clinical outcomes

Qualitative D-dimer results, together with clinical probability scores, are well established in the diagnosis of venous thromboembolism (VTE). The predictive value of quantitative D-dimer levels for various clinical outcomes in VTE patients is not fully understood. D-dimer levels obtained at presentation were analysed in 699 (360 men; 339 women) VTE patients for survival and occurrence of malignancy. Patients were followed for a median of 23 months. 17.2% patients had a D-dimer level >8000 ng FEU/mlat presentation, which was associated with decreased overall survival (OS) (P < 0.001) and event-free survival (EFS) (P < 0.001). 25.4% patients had malignancy and 4% subsequently developed malignancy following VTE. 29.9% of patients with VTE and malignancy had a D-dimer level >8 mg/l when compared with 13.4% of patients with VTE without malignancy (P < 0.001). 50% of patients who developed subsequent malignancy following VTE had a presentation D-dimer >8000 ng FEU/mlas compared with 13.3% of patients with VTE with out malignancy (P = 0.009). In conclusion, D-dimer >8000 ng FEU/ml at presentation in patients with VTE is a marker of poor OS, EFS and underlying malignancy. Consideration of screening for malignancy is recommended in patients with VTE with a presentation D-dimer >8000 ng FEU/ml and age >60 years.

The performance of STA-Liatest D-dimer assay in out-patients with suspected pulmonary embolism

Several studies have shown that D-dimer can reliably rule out pulmonary embolism (PE) in out-patients. However, various assays have different sensitivities and specificities to detect thrombosis. Our aim was to evaluate the performance of STA-Liatest D-Di in out-patients referred for suspected PE in a prospective outcome study. 495 consecutive patients referred to Østfold Hospital Trust-Fredrikstad, Norway for suspected PE between February 2002 and December 2003, were recruited in a study evaluating a decision-based algorithm combining clinical probability (CP), D-dimer, and multi-slice computer tomography (MSCT). D-dimer was performed as a first step test. No further testing was carried out in patients with D-dimer < or =0.4 mg/l and low/intermediate CP. The remaining patients proceeded to MSCT. All patients were followed up for 3 months to assess the 3-month thromboembolic risk. The final cohort consisted of 432 patients. PE was diagnosed in 102 (23%) patients. At a D-dimer cut-off point of 0.4 mg/l the tests had the highest sensitivity (100%) and specificity (36%). It safely ruled out PE in 120 (28%) patients. Kappa-coefficients for comparisons versus VIDAS and Asserachrom showed good concordance. STA-Liatest is a reliable and effective assay that can safely rule out PE in out-patients with a performance comparable with that of enzyme-linked immunosorbent assay-based d-dimer levels.

Advances in the Diagnosis of Venous Thromboembolism

This review summarizes recent information about the diagnosis of deep venous thrombosis (DVT) and pulmonary embolism (PE) using noninvasive imaging tests, clinical assessment, and D-dimer assays, and describes how these tests can be employed in diagnostic testing algorithms for the investigation of patients with suspected DVT and PE. The clinical diagnosis of deep venous thrombosis is unreliable, but clinical prediction rules based on signs and symptoms do facilitate the categorization of patients into high, low, or medium risk categories. High sensitivity D-dimer assays further help in excluding cases but do not help in ruling in venous thromboembolism. D-dimer assays and clinical prediction rules also help in the diagnosis of pulmonary embolism. These assessments, along with objective imaging studies such as compression ultrasonography for DVT or computerized tomographic pulmonary angiograms for PE can be used in a systematic way to reliably rule in or exclude venous thromboembolism.

Update in the diagnosis of deep-vein thrombosis and pulmonary embolism

PURPOSE OF REVIEW

Diagnostic strategies for venous thromboembolism must both accurately diagnose thrombus when present, and safely exclude it when absent. This review summarizes recent data on diagnostic strategies for venous thromboembolism.

RECENT FINDINGS

Noninvasive diagnostic strategies have emerged to limit the need for invasive testing for deep-vein thrombosis and pulmonary embolism. D-Dimer testing combined with clinical assessment can be used to safely exclude deep vein thrombosis, limiting the need for further testing. Extended lower limb ultrasonography also shows promise although requires further data. Spiral computed tomography has become widely used for the diagnosis of pulmonary embolism. Evidence either for the use of single-detector spiral computed tomography combined with ultrasound or for multidetector spiral computed tomography as a safe and stand-alone test, for the purpose of excluding pulmonary embolism, is finally catching up with current practice.

SUMMARY

Invasive testing for venous thromboembolism can be safely avoided in the majority of patients, using diagnostic strategies combining noninvasive tests. Initial evidence suggests that multidetector spiral computed tomography is a safe stand-alone test for pulmonary embolism. Local cost and expertise with separate diagnostic tests will influence the appropriate choice of diagnostic strategies for venous thromboembolism at individual institutions.