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.

Pulmonary embolism prevalence among emergency department cohorts: A systematic review and meta-analysis by country of study

Essentials The threshold to test for pulmonary embolism (PE) might be lower in North America than Europe. We compared the PE prevalence and positive yield of imaging in Europe and North America. More patients tested in Europe are diagnosed with PE, and imaging is more often positive. Our systematic review supports the hypothesis of overtesting for PE in North America. ABSTRACT: Background There is an impression that North American emergency department (ED) patients tested for pulmonary embolism (PE) differ from European ones. Objectives We compared the PE prevalence, frequency of use, and positive yield of imaging among ED patients tested for PE in Europe and North America. Methods We searched for studies reporting consecutive ED patients tested for PE. Two authors screened full texts, performed risk of bias assessment, and data extraction. We conducted a meta-analysis of proportions for each outcome and a multiple meta-regression. Results From 3109 publications, 44 were included in the systematic review. The prevalence of PE in Europe was 23% (95% confidence interval [CI], 21-26) and in North America 8% (95% CI, 6-9). The adjusted mean difference (aMD) in the prevalence of PE in the European compared with North American studies, was 15% (95% CI, 10-20). Computed tomography pulmonary angiography (CTPA) was used in 60% (95% CI, 52%-68) of European and 38% (95% CI, 24-51) of North American patients tested for PE (aMD, 23% [95% CI, 7-39]). The CTPA diagnostic yield was 29% (95% CI, 26-32) in Europe and 13% (95% CI, 9-17) in North America (aMD, 15% [95% CI, 8-21]). Conclusion Compared with North America, European ED studies have a higher prevalence of PE and diagnostic yield from CTPA, despite a higher frequency of CTPA use among patients tested for PE. This supports the hypothesis that those tested for PE in North American EDs have a lower risk of PE compared with Europe.

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.

Obesity, Thrombotic Risk, and Inflammation in Cancer

Neoplasms exhibits a high incidence and mortality rates due to their complex and commonly overlapping clinical, biochemical, and morphologic profiles influenced by acquired or inherited molecular abnormalities, cell of origin, and level of differentiation. Obesity appears related to ~20% of cancers including endometrial, esophageal, colorectal, postmenopausal breast, prostate, and renal. Several factors other than obesity, i.e., insulin, insulin-like growth factor, sexual hormones, and adipokines may play a potential role in neoplasia. Cancer-associated hypercoagulable and thrombotic states are influenced by abnormalities in the vascular wall and susceptibility to invasion, interference in blood flow and increase in circulating tissue factor and thrombin, activation of cell growth factors, the presence of a central catheter, chemotherapies, neoplasm type, and surgery. In cancer, thromboembolic complications are the second most frequent cause of death with pulmonary thromboembolism in ~50% of cases postmortem. Thrombosis worsens prognosis as demonstrated with a survival rate as low as 12% per year vs 36% in nonthrombic patients. Deep vein thrombosis is the most frequent thromboembolic complication in cancer. It is usually detected at diagnosis and within the first 3 months of chemotherapy. The underlining mechanisms of this association should be further studied to identify patients at higher risk and develop adequate prevention, diagnostic, and treatment measures. The D-dimer test can be successfully used to assess the fibrinolytic phase of coagulation and as such is routinely used in suspected cases of deep vein thrombosis and pulmonary thromboembolism. In addition, significant advances have been made in understanding the composition and functional capabilities of the gut microbiota in the inflammatory process, obesity, and its roles in cancer; however, the intricate balance that exists within the microbiota may not only affect the host directly, it can also disrupt the entire microbial community.

CONCLUSIONS

Cancer is a prothrombotic and inflammatory state in which the activation of coagulation is related to tumor growth, angiogenesis, and metastasis. It is important to identify the relationship between body mass index with these processes and clarify their importance in cancer prognosis. Future research should answer the question if manipulation of resident microbial communities could potentially improve prognosis and treatment outcome.

Evaluation of soluble fibrin and D-dimer in the diagnosis of postoperative deep vein thrombosis

Soluble fibrin (SF) and D-dimer are useful for making the diagnosis of deep vein thrombosis (DVT). However, the evidence for using such markers and optimal timing to diagnose postoperative DVT are unclear. We evaluate the usefulness of SF and D-dimer testing for the diagnosis of postoperative DVT. A total of 207 patients who had total hip arthroplasty or knee arthroplasty were evaluated. SF and D-dimer were tested on postoperative days 1 and 7. DVT was confirmed with ultrasonography. SF level on postoperative day 1 was the most useful, although D-dimer evaluation on postoperative days 1 and 7 was also useful. Using a SF cut-off of more than 4.00 microg ml(-1), the sensitivity was 90%, the specificity was 33%. Although the SF and D-dimer tests cannot be used as stand-alone tests, SF and D-dimer are valuable screening tools. We recommend two-stage screening including first with the SF or D-dimer test, followed by ultrasonography or venography.