scholarly journals LO55: Comparison of the age-adjusted D-dimer, clinical probability-adjusted D-dimer, and Wells rule with D-dimer for diagnosing deep vein thrombosis in the emergency department.

CJEM ◽  
2020 ◽  
Vol 22 (S1) ◽  
pp. S27-S27
Author(s):  
S. Sharif ◽  
C. Kearon ◽  
M. Eventov ◽  
P. Sneath ◽  
M. Li ◽  
...  

Introduction: Diagnosing deep vein thrombosis (DVT) is of critical importance because of its associated morbidity and mortality. Diagnosing DVT can be challenging in the Emergency Department (ED) due to inconsistent adherence to, and utilization of the Wells rule. Both the age-adjusted and clinical probability adjusted D-dimer have been shown to decrease ultrasound (US) utilization rates. We aimed to compare the safety and efficacy of the Wells score with D-dimer to the age-adjusted and clinical probability-adjusted D-dimer in Canadian ED patients tested for DVT. Methods: This was a health records review of ED patients investigated for DVT at two EDs over a two-year period. Inclusion criteria were ED physician ordered duplex ultrasonography or D-dimer for investigation of lower limb DVT. Patients under the age of 18 were excluded. DVT was considered to be present during the ED visit if DVT was diagnosed on duplex ultrasonography and was treated for acute DVT, or if the patient was subsequently diagnosed with pulmonary embolism (PE) or DVT during the next 30 days. Trained researchers extracted anonymized data. The Wells D-dimer, age-adjusted D-dimer, and the clinical probability-adjusted D-dimer rules were applied retrospectively. The rate of duplex ultrasonography imaging and the false negative rate was calculated for each rule. Results: Between April 1st 2013 and March 31st 2015, there were 1,198 patients tested for DVT. Of the low and moderate clinical pretest probability patients (Wells score ≤ 2), only 436 had a D-Dimer test and were eligible for our analysis. The average age of the patients was 59, 56% were female, and 4% had a malignancy. 207/436 patients (47.4%, 95%CI 42.8-52.2%) would have had US imaging for DVT if the age-adjusted D-dimer rule was used. 214/436 patients (49.1%, 95%CI 44.4-53.8%) would have had imaging for DVT if the clinical probability-adjusted D-dimer was used. If the Wells rule was used with the standard D-dimer cutoff of 500, 241/436 patients (55.2%, 95%CI 50.6-59.9%) would have had imaging for DVT. The false-negative rate for the Wells rule was 1.5% (95%CI 0.5-4.4%). The false-negative rate for the age-adjusted D-dimer rule was 1.3% (95%CI 0.4-3.8%). The false-negative rate for the clinical-probability adjusted D-Dimer was 1.8% (95%CI 0.7-4.5%). Conclusion: In comparison with the approach of the Wells score and D-dimer, both the age-adjusted and clinical probability-adjusted D-dimer diagnostic strategies could reduce the proportion of patients who require US imaging.

CJEM ◽  
2017 ◽  
Vol 19 (S1) ◽  
pp. S116
Author(s):  
S. Sharif ◽  
C. Kearon ◽  
M. Li ◽  
M. Eventov ◽  
R. Jiang ◽  
...  

Introduction: Diagnosing pulmonary embolism (PE) in the emergency department can be challenging due to non-specific signs and symptoms; this often results in the over-utilization of CT pulmonary angiography (CT-PA). In 2013, the American College of Chest Physicians identified CT-PA as one of the top five avoidable tests. Age-adjusted D-dimer has been shown to decrease CT utilization rates. Recently, clinical-probability adjusted D-dimer has been promoted as an alternative strategy to reduce CT scanning. The aim of this study is to compare the safety and efficacy of the age-adjusted D-dimer rule and the clinical probability-adjusted D-dimer rule in Canadian ED patients tested for PE. Methods: This was a retrospective chart review of ED patients investigated for PE at two hospitals from April 2013 to March 2015 (24 months). Inclusion criteria were the ED physician ordered CT-PA, Ventilation-Perfusion (VQ) scan or D-dimer for investigation of PE. Patients under the age of 18 were excluded. PE was defined as CT/VQ diagnosis of acute PE or acute PE/DVT in 30-day follow-up. Trained researchers extracted anonymized data. The age-adjusted D-dimer and the clinical probability-adjusted D-dimer rules were applied retrospectively. The rate of CT/VQ imaging and the false negative rates were calculated. Results: In total, 1,189 patients were tested for PE. 1,129 patients had a D-dimer test and a Wells score less than 4.0. 364/1,129 (32.3%, 95%CI 29.6-35.0%) would have undergone imaging for PE if the age-adjusted D-dimer rule was used. 1,120 patients had a D-dimer test and a Wells score less than 6.0. 217/1,120 patients (19.4%, 95%CI 17.2-21.2%) would have undergone imaging for PE if the clinical probability-adjusted D-dimer rule was used. The false-negative rate for the age-adjusted D-dimer rule was 0.3% (95%CI 0.1-0.9%). The false-negative rate of the clinical probability-adjusted D-dimer was 1.0% (95%CI 0.5-1.9%). Conclusion: The false-negative rates for both the age-adjusted D-dimer and clinical probability-adjusted D-dimer are low. The clinical probability-adjusted D-dimer results in a 13% absolute reduction in CT scanning compared to age-adjusted D-dimer.


2017 ◽  
Vol 33 (7) ◽  
pp. 458-463 ◽  
Author(s):  
Efrem Gómez-Jabalera ◽  
Sergio Bellmunt Montoya ◽  
Eva Fuentes-Camps ◽  
José Román Escudero Rodríguez

Objective In the diagnosis of deep vein thrombosis, new D-dimer cut-off values were defined by multiplying 10 µg/L × age. The objective of the present study is to define a more specific age-adjusted value, including the pre-test Wells score, without worsening sensitivity. Methods We designed a case–control study in patients attended in the emergency department with clinically suspected deep vein thrombosis. Demographics, Wells score, D-dimer and ultrasound data were collected. In low and intermediate clinical probability cases for deep vein thrombosis, we determined the specificity and sensitivity (false-negative rates) for the following cut-off values of D-dimer: age × 10 µg/L, age × 15 µg/L, age × 20 µg/L, age × 25 µg/L and age × 30 µg/L. The cut-off value with maximum specificity without any false-negative result (sensitivity 100%) was identified. Results We included 138 consecutive patients, 39.9% were men and the mean age was 71.6 years. Deep vein thrombosis was diagnosed in 16.7% of patients and the Wells score was low in 69.6%, intermediate in 21% and high in 9.4% of patients. Applying the conventional cut-off value of 500 µg/L, the specificity was 21.1% with a sensitivity of 100%. Maintaining 100% sensitivity, the highest specificity was reached with a cut-off value for D-dimer equivalent to the age × 25 µg/L in low-risk patients (67.1% specificity) and the age × 10 µg/L (50% specificity) in intermediate-risk patients. Conclusions In patients with low Wells score, the cut-off value can be raised to age × 25 µg/L in order to rule out deep vein thrombosis without jeopardizing safety. In intermediate-risk patients, the D-dimer cut-off value could be raised to age × 10 µg/L as previously suggested.


CJEM ◽  
2018 ◽  
Vol 20 (S1) ◽  
pp. S105-S105 ◽  
Author(s):  
S. Sharif ◽  
C. Kearon ◽  
M. Eventov ◽  
M. Li ◽  
R. Jiang ◽  
...  

Introduction: Diagnosing pulmonary embolism (PE) can be challenging because the signs and symptoms are often non-specific. Studies have shown that evidence-based algorithms are not always adhered to in the Emergency Department (ED) and are often not used correctly, which leads to unnecessary CT scanning. The YEARS diagnostic algorithm, consisting of three items (clinical signs of deep vein thrombosis, hemoptysis, and whether pulmonary embolism is the most likely diagnosis) and D-dimer, is a novel and simplified way to approach suspected acute PE. The purpose of this study was to 1) evaluate the use of the YEARS algorithm in the ED and 2) to compare the rates of testing for PE if the YEARS algorithm was used. Methods: This was a health records review of ED patients investigated for PE at two emergency departments over a two-year period (April 2013-March 2015). Inclusion criteria were ED physician ordered CT pulmonary angiogram, ventilation-perfusion scan, or D-dimer for investigation of PE. Patients under the age of 18 and those without a D-dimer test were excluded. PE was considered to be present during the emergency department visit if PE was diagnosed on CT or VQ (subsegmental level or above), or if the patient was subsequently found to have PE or deep vein thrombosis during the next 30 days. Trained researchers extracted anonymized data. The rate of CT/VQ imaging and the false negative rate was calculated. Results: There were 1,163 patients that were tested for PE and 1,083 patients were eligible for our analysis. Of the total, 317/1,083 (29.3%; 95%CI 26.6-32.1%) had CT/VQ imaging for PE, and 41/1,083 (3.8%; 95%CI 2.8-5.1%) patients were diagnosed with PE at baseline. Three patients had a missed PE, resulting in a false negative rate of 0.4% (95%CI 0.1-1.2%). If the YEARS algorithm was used, 211/1,083 (19.5%; 95%CI 17.2-22.0%) would have required imaging for PE. Of the patients who would not have required imaging according to the YEARS algorithm, 8/872 (0.9%; 95%CI 0.5-1.8%) would have had a missed PE. Conclusion: If the YEARS algorithm was used in all patients with suspected PE, fewer patients would have required imaging with a small increase in the false negative rate.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3218-3218
Author(s):  
Kerstin De Wit ◽  
Sameer Parpia ◽  
Adam Sunavsky ◽  
Aleksandrija Ilic ◽  
Federico Germini ◽  
...  

Abstract Introduction There are evidence-based protocols for the diagnosis and exclusion of pulmonary embolism (PE) and deep vein thrombosis (DVT) which include clinical probability scoring along with selective D-dimer testing and diagnostic imaging. D-dimer assessment in VTE (venous thromboembolism) testing tends to be omitted in patients with cancer, partly because of perceived D-dimer lack of sensitivity and specificity. The aim of this systematic review and meta-analysis was to report the diagnostic accuracy of D-dimer for PE and lower limb DVT in patients with cancer. This study was part of a research program to set International Society of Thrombosis and Haemostasis standards for VTE testing in patients with cancer. Methods This systematic review and meta-analysis followed the MOOSE guidelines and was registered in PROSPERO, CRD42020181007. We searched Medline via OVID from conception to 12 th March 2020 for diagnostic PE and DVT studies reporting on people with cancer, or a subgroup of people with cancer. Researchers in the field were contacted for information on unpublished studies. All languages were included. Two researchers screened the titles and abstracts. Four researchers reviewed the selected full texts to determine which studies fulfilled inclusion criteria. Two researchers assessed risk of bias using QUADAS-2, extracted data on the true positive, false positive, true negative and false negative results for D-dimer alone, and D-dimer combined with clinical probability estimation. We used the bivariate random effects method to meta-analyze sensitivity and specificity values. We used a random effects model to estimate pooled false negative rates and efficiency for combining a negative D-dimer (manufacturer recommended cutoff) with a low clinical probability to exclude PE or DVT in patients with cancer. Results were displayed on a Forest plot. Heterogeneity was assessed using I 2. Results From 7947 titles and abstracts, we reviewed 49 full text manuscripts, including 13 studies for analysis. Risk of bias was low across all domains for only 5/13 studies. Figures 1 shows the Forest plots grouped by sensitivity and specificity for PE and DVT. The pooled estimates for D-dimer in the diagnosis of VTE in cancer patients (regardless of clinical probability) were 96.4% (95% confidence interval (CI) 94.8 to 97.5%) sensitivity and 26.4% (95% CI 18.1 to 37.0%) specificity. For PE, D-dimer was 96.9% (96.1 to 97.5%) sensitive (I 2 0%, N=2,299) and 14.0% (12.1 to 16.0%) specific, (I 2 69%, N=11,455). For DVT, D-dimer was 94.3% (89.8 to 97.6%) sensitive, (I 2 61%, N=546) and 46.4% (39.8 to 53.3%) specific, (I 2 59%, N=724). The efficiency of combining a low D-dimer (using the manufacturer recommended cutoff) and low clinical probability to exclude DVT or PE was 9.3%, (95% CI 6.9 to 11.9%), N=1,347. There were only 122 patients in the false negative rate analysis of whom 1 patient was diagnosed with VTE in follow up. A pooled analysis was not performed for the false negative rate. Conclusions D-dimer is a sensitive test for both PE and lower limb DVT in people who have cancer. Approximately 10% of patients with cancer and suspected VTE can have VTE excluded with D-dimer and clinical probability prior to ordering diagnostic imaging. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.


CJEM ◽  
2017 ◽  
Vol 19 (S1) ◽  
pp. S56
Author(s):  
S. Sharif ◽  
C. Kearon ◽  
M. Li ◽  
M. Eventov ◽  
P.E. Sneath ◽  
...  

Introduction: Diagnosing pulmonary embolism (PE) can be challenging because the signs and symptoms are often non-specific. Studies have shown that evidence-based diagnostic algorithms are not always adhered to in the Emergency Department (ED), which leads to unnecessary CT scanning. In 2013, the American College of Chest Physicians identified CT pulmonary angiography as one of the top five avoidable tests. One solution is to use a clinical prediction rule combined with the D-dimer, which safely reduces the use of CT scanning. The objective of this study was to compare the proportion of patients tested for PE in two emergency departments, who 1) had a CT-PE and 2) whose diagnosis of PE was missed. We compared these rates to those if the Wells rule and D-dimer had been applied as standard. Methods: This was a retrospective chart review of ED patients investigated for PE at two hospitals from April 2013 to March 2015 (24 months). Inclusion criteria were the ED physician ordered CT-PE, Ventilation-Perfusion (VQ) scan or D-dimer for investigation of PE. Patients under the age of 18 were excluded. PE was defined as CT/VQ diagnosis of acute PE or acute PE/DVT in 30-day follow-up. Trained researchers extracted anonymized data. The rate of CT/VQ imaging and the false-negative rates were calculated. The false-negative rate was calculated as the number of patients diagnosed with PE within 30 days as a proportion of those patients who did not have a CT/VQ scan at initial presentation. Results: There were 1,189 patients included in this study. 55/1,189 patients (4.6%; 95%CI 3.6-6.0%) were ultimately diagnosed with PE within 30 days. 397/1,189 patients (33.4%; 95%CI 30.8-36.1%) had CT/VQ scans for PE. 3 out of 792 who were not scanned had a missed PE resulting in a false-negative rate of 0.4% (95% CI 0.1-1.1%). 80 patients had an elevated D-dimer or high Wells score but were not imaged. Furthermore, 75 patients who did not have an elevated D-dimer nor a high Wells score were imaged. Had Wells rule/D-dimer been adhered to, 402/1,189 patients (33.8%; 95%CI 31.9-36.6%) would have undergone imaging and the false negative rate would be 0/727, 0% (95%CI 0.0-0.5%). Conclusion: If the Wells rule and D-dimer was used in all patients tested for PE, a similar proportion would have a CT scan but fewer PEs would be missed.


2012 ◽  
Vol 107 (02) ◽  
pp. 369-378 ◽  
Author(s):  
Jan Schwonberg ◽  
Carola Hecking ◽  
Marc Schindewolf ◽  
Dimitrios Zgouras ◽  
Susanne Lehmeyer ◽  
...  

SummaryThe diagnostic value of D-dimer (DD) in the exclusion of proximal deep-vein thrombosis (DVT) is well-established but is less well-known in the exclusion of distal (infrapopliteal) DVT. Therefore, we evaluated the diagnostic abilities of five DD assays (Vidas-DD, Liatest-DD, HemosIL-DD, HemosIL-DDHS, Innovance-DD) for excluding symptomatic proximal and distal leg DVT. A total of 243 outpatients whose symptoms were suggestive of DVT received complete compression ultrasonography (cCUS) of the symptomatic leg(s). The clinical probability of DVT (PTP) was assessed by Wells score. Thirty-eight proximal and 31 distal DVTs (17 tibial/fibular DVTs, 14 muscle DVTs) were diagnosed by cCUS. Although all assays showed high sensitivity for proximal DVT (range 97–100%), the sensitivity was poor for distal DVT (range 78–93%). None of the assays were individually able to rule out all DVTs as a stand-alone test (negative predictive value [NPV] 91–96%). However, a negative DD test result combined with a low PTP exhibited a NPV of 100% for all DVTs (including proximal, tibial/fibular, and muscle DVTs) with the HemosIL-DDHS and Innovance-DD. All proximal and tibial/fibular DVTs, but not all muscle DVTs, could be ruled out with this strategy using the Liatest-DD and Vidas-DD. The HemosIL-DD could not exclude distal leg DVT, even in combination with a low PTP. The combination of a negative DD with a low PTP showed a specificity of 32–35% for all DVTs. In conclusion, our study shows that when used in conjunction with a low PTP some DD assays are useful tools for the exclusion of distal leg DVT.


CJEM ◽  
2018 ◽  
Vol 20 (S1) ◽  
pp. S13-S14
Author(s):  
K. Al Lawati ◽  
J. Aljazeeri ◽  
W. Chan ◽  
K. de Wit

Introduction: The accuracy of ultrasound (US) for diagnosing lower extremity deep vein thrombosis (DVT) in non-pregnant patients has been well validated. However, in pregnant women with suspected DVT and an initial negative US (with imaging of the iliac veins), serial US is recommended. We aimed to determine the ability of single negative US to exclude DVT in symptomatic pregnant women. Methods: Two authors independently reviewed the following databases: MEDLINE, PubMed and EMBase from inception until May 2017. Three authors reviewed all full text papers and data were extracted from included studies by four authors. An overlap among study populations was identified in 4 of the manuscripts, all from one multicentre Canadian study. Two authors performed data re-extraction from the hard copy research charts from this study. We assessed the risk of bias using the CLARITY group tool for prognostic studies. Results: Of 109 potentially relevant articles, 8 studies (7 prospective studies and 1 retrospective) were included. Risk of bias was low for the included populations, and low or moderate for method of measurement and for completeness of follow up. A total of 635 pregnant patients with symptoms of DVT had an initial negative US examination. Of those, 6 had positive DVT during serial US (0.94%) and 3 developed DVT during 3-month follow-up after serial ultrasound (0.47%). Using random-effects model, the pooled false negative rate of a single ultrasound was 1.27% (95% confidence interval, 0.42 to 2.56), I2= 27%. Conclusion: The false negative rate of a single ultrasound with iliac vein imaging for DVT in pregnancy is low. Our results will help inform shared decision making around planning repeat ultrasound scans in these patients.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4265-4265
Author(s):  
Anna Tran ◽  
Kerstin De Wit ◽  
Darshana Seeburruth

Abstract Introduction It is unclear whether evidence-based diagnostic protocols are followed when cancer patients are tested for venous thromboembolism (VTE). Evidence-based protocols reduce unnecessary diagnostic imaging, offer a patient-centered approach, and have the potential to standardize practice across medical specialties and settings. However, anecdote suggests that specialists who test people with cancer for VTE may prefer diagnostic imaging over clinical probability scoring and D-dimer testing. The aim of this study was to identify physician and patient knowledge, beliefs, values and preferences for VTE testing in cancer. This study was part of a program of research to set International Society of Thrombosis and Haemostasis standards for VTE testing in people with cancer. Methods This was an international qualitative interview study following COREQ guidelines. Semi-structured interviews with physicians and cancer patients were conducted via Zoom. We used purposive sampling to ensure inclusion of physicians from all specialties who test people with cancer for VTE, practicing across all continents. We invited people treated for cancer who had and did not have experience of VTE testing. We used grounded theory to create a conceptual framework which explains physician and patient values and preferences for VTE testing. Transcripts were coded by three researchers independently, who met to discuss their findings and agree on common codes. Researchers were a Thrombosis physician and two undergraduate students who ensured reflexivity was incorporated into their analysis. Results A total of 32 physicians and 6 cancer patients were invited to interview. Of those invited, 23 physicians and 6 patients across 6 continents completed an interview. Interviews lasted between 21 and 86 minutes. Our derived conceptual model can be seen in the attached Figure. Physicians reported a low threshold to test for VTE in people with cancer compared to those without cancer, because VTE was considered a fatal disease and highly prevalent in this patient population. Imaging was generally the only test used for VTE testing in cancer patients. Many participants relied on their Gestalt estimation of VTE probability when deciding whether to order imaging for pulmonary embolism or deep vein thrombosis. Most thought that low Wells score in combination with a negative D-dimer was not sufficiently sensitive to exclude VTE and anticipated the Wells score and D-dimer to be elevated. The Wells scores had poor face validity because they do not include cancer-specific variables and participants hoped to see a more nuanced formal score for VTE testing in cancer patients. Participants believed that their colleagues would support their diagnostic approach. Patients reported they were used to having tests and CT scans. Patients felt it was important for their physicians to prioritize testing for VTE. Patients had full trust and confidence in their physicians' testing decisions, particularly in decisions made by their oncologists. Conclusion Physicians have a low threshold to test people with cancer for VTE and tend not to use clinical probability assessment and D-dimer. Patients are comfortable having diagnostic imaging, feel VTE testing is important and have full trust in their physicians. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.


2020 ◽  
Vol 7 (2) ◽  
pp. 332
Author(s):  
Nehad Abdou Zaid ◽  
Mahmoud S. El Desoky ◽  
Seham F. Attia

Background: To reduce unnecessary venous ultrasound examination in cases suspected to have deep venous thrombosis (DVT) in emergency department by using D dimer and wells score. venous duplex is widely used to diagnose DVT increasing burden on ultrasound in overcrowded emergency department. Authors can decrease this burden by using clinical probability scores and D dimer.Methods: This is prospective study done on 50 consecutive patients suspected to have DVT represented to emergency department of   Menoufia University Hospital during the period from June 2018 to June 2019. Full history, physical examination, assessment of clinical probability score, d dimer level and results of venous duplex collection.Results: According to wells score, the majority of cases diagnosed as DVT were of high probability group 13(68.4%), 5 patients with moderate probability and only one patient with low probability was diagnosed as DVT. The mean of D dimer level in cases diagnosed as DVT is (4173.6±2173.1) and in cases without DVT is (927.4±1064.6). Using wells score and D dimer together, sensitivity is 100%, Specificity is 94%. PPV is 90%, and NPV is 100% in predicting DVT. All cases with negative d dimer and low risk probability do not have DVT.Conclusions: Based on this result, using wells score and d dimer level in early work up of patients suspected to have DVT will decrease overusing and cost of venous duplex.


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