An algorithm for the investigation and management of patients with suspected deep venous thrombosis at a district general hospital

Current use of D-dimer for the exclusion of venous thrombosis in hospitalized patients

D-dimer assay’s utility for excluding venous thromboembolism (VTE) in hospitalized patients is debatable. We aimed to assess the current use of D-dimer as a diagnostic tool for excluding VTE in hospitalized patients and examine a mandatory age-adjusted D-dimer (AADD) threshold for diagnostic imaging. Retrospective cohort study between 2014 to 2019 that included patients from medical and surgical wards with a positive AADD result drawn during their hospitalization. The outcomes were determining a D-dimer threshold requiring further evaluation and assessing the prognostic value of D-dimer in predicting clinically relevant VTE in hospitalized patients. The cohort included 354 patients, 56% of them underwent definitive diagnostic imaging, and 7.6% were diagnosed with VTE after a positive AADD within 90 days of follow-up. Mortality rates were higher in patients diagnosed with VTE (33.3% vs. 15.9%, p = 0.03). Patients with pneumonia and other infectious etiologies were less likely to be further evaluated by definitive imaging (p = 0.001). Patients with a respiratory complaint (p = 0.02), chest pain (p < 0.001), or leg swelling (p = 0.01) were more likely to undergo diagnostic imaging. Patients with D-dimer levels > X2 the AADD were at increased risk of VTE [OR 3.87 (1.45–10.27)]. At 90 days of follow-up, no excess mortality was observed for patients without diagnostic evaluation following elevated AADD. D-dimer may be used in hospitalized patients to exclude VTE using the traditional AADD thresholds, with a high negative predictive value. D-dimer levels > X2 the AADD usually mandates further diagnostic imaging, while lower levels, probably do not require additional workup, with a sensitivity of almost 80% and no excess mortality.

A systematic review of clinical prediction scores for deep vein thrombosis

Objective Diagnosis of deep vein thrombosis remains a challenging problem. Various clinical prediction rules have been developed in order to improve diagnosis and decision making in relation to deep vein thrombosis. The purpose of this review is to summarise the available clinical scores and describe their applicability and limitations. Methods A systematic search of PubMed, MEDLINE and EMBASE databases was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidance using the keywords: clinical score, clinical prediction rule, risk assessment, clinical probability, pretest probability, diagnostic score and medical Subject Heading terms: 'Venous Thromboembolism/diagnosis' OR 'Venous Thrombosis/diagnosis'. Both development and validation studies were eligible for inclusion. Results The search strategy returned a total of 2036 articles, of which 102 articles met a priori criteria for inclusion. Eight different diagnostic scores were identified. The development of these scores differs in respect of the population included (hospital inpatients, hospital outpatients or primary care patients), the exclusion criteria, the inclusion of distal deep vein thrombosis and the use of D-dimer. The reliability and applicability of the scores in the context of specific subgroups (inpatients, cancer patients, elderly patients and those with recurrent deep vein thrombosis) remains controversial. Conclusion Detailed knowledge of the development of the various clinical prediction scores for deep vein thrombosis is essential in understanding the power, generalisability and limitations of these clinical tools.

Diagnosis of DVT: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

Objective testing for DVT is crucial because clinical assessment alone is unreliable and the consequences of misdiagnosis are serious. This guideline focuses on the identification of optimal strategies for the diagnosis of DVT in ambulatory adults.

METHODS

The methods of this guideline follow those described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.

RESULTS

We suggest that clinical assessment of pretest probability of DVT, rather than performing the same tests in all patients, should guide the diagnostic process for a first lower extremity DVT (Grade 2B). In patients with a low pretest probability of first lower extremity DVT, we recommend initial testing with D-dimer or ultrasound (US) of the proximal veins over no diagnostic testing (Grade 1B), venography (Grade 1B), or whole-leg US (Grade 2B). In patients with moderate pretest probability, we recommend initial testing with a highly sensitive D-dimer, proximal compression US, or whole-leg US rather than no testing (Grade 1B) or venography (Grade 1B). In patients with a high pretest probability, we recommend proximal compression or whole-leg US over no testing (Grade 1B) or venography (Grade 1B).

CONCLUSIONS

Favored strategies for diagnosis of first DVT combine use of pretest probability assessment, D-dimer, and US. There is lower-quality evidence available to guide diagnosis of recurrent DVT, upper extremity DVT, and DVT during pregnancy.

Managing suspected venous thromboembolism in a mixed primary and secondary care setting using standard clinical assessment and D-dimer in a noninvasive diagnostic strategy

Venous thromboembolism is a potentially lethal disease if not properly treated. Noninvasive strategies have become an attractive clinical option for effective diagnosis. There has been controversy, however, regarding the use of standard clinical rules in a primary care setting. The objective of the present study was to validate a noninvasive diagnostic strategy in an emergency unit giving assistance to patients with primary and secondary care needs. A total of 291 outpatients (primary and secondary care needs) with suspected venous thromboembolism attending the emergency unit of a general hospital from August 2002 to 2004 were retrospectively evaluated. The diagnostic strategy included assessment of risk for venous thromboembolism and a rapid quantitative enzyme-linked immunosorbent assay D-dimer test. Venous thromboembolism was ruled out in patients with a low-probability or intermediate-probability risk (or an unlikely diagnosis) and a negative D-dimer. The prevalence of venous thromboembolism was 8.2%. Patients with an unlikely diagnosis comprised 93.8% of the evaluations for deep venous thrombosis, and those with a low probability for pulmonary embolism comprised 81.4%. Proportions of patients with venous thromboembolic events observed were 7.2% in patients with an unlikely diagnosis of deep venous thrombosis and 3.0% in those with low probability for pulmonary embolism. The percentage of patients with a thrombotic event excluded using this strategy was 37% (positive predictive value 13%, negative predictive value 100%). In conclusion, this noninvasive clinical strategy is safe for ruling out venous thromboembolism, and excludes the need for imaging tests in about one-third of the patients in the population studied.

Painful swollen leg--think beyond deep vein thrombosis or Baker's cyst

BACKGROUND

The diagnosis of deep vein thrombosis of leg is very common in clinical practice. Not infrequently a range of pathologies are diagnosed after excluding a thrombosis, often after a period of anticoagulation.

CASE PRESENTATION

This is a report of three patients who presented with a painful swollen leg and were initially treated as a deep vein thrombosis or a baker's cyst, but later diagnosed as a pleomorphic sarcoma, a malignant giant cell tumor of the muscle and a myxoid liposarcoma. A brief review of such similar reports and the relevant literature is presented.

CONCLUSION

A painful swollen leg is a common clinical scenario and though rare, tumors must be thought of without any delay, in a duplex negative, low risk deep vein thrombosis situation.

Systematic review and meta-analysis of the diagnostic accuracy of ultrasonography for deep vein thrombosis

BACKGROUND

Ultrasound (US) has largely replaced contrast venography as the definitive diagnostic test for deep vein thrombosis (DVT). We aimed to derive a definitive estimate of the diagnostic accuracy of US for clinically suspected DVT and identify study-level factors that might predict accuracy.

METHODS

We undertook a systematic review, meta-analysis and meta-regression of diagnostic cohort studies that compared US to contrast venography in patients with suspected DVT. We searched Medline, EMBASE, CINAHL, Web of Science, Cochrane Database of Systematic Reviews, Cochrane Controlled Trials Register, Database of Reviews of Effectiveness, the ACP Journal Club, and citation lists (1966 to April 2004). Random effects meta-analysis was used to derive pooled estimates of sensitivity and specificity. Random effects meta-regression was used to identify study-level covariates that predicted diagnostic performance.

RESULTS

We identified 100 cohorts comparing US to venography in patients with suspected DVT. Overall sensitivity for proximal DVT (95% confidence interval) was 94.2% (93.2 to 95.0), for distal DVT was 63.5% (59.8 to 67.0), and specificity was 93.8% (93.1 to 94.4). Duplex US had pooled sensitivity of 96.5% (95.1 to 97.6) for proximal DVT, 71.2% (64.6 to 77.2) for distal DVT and specificity of 94.0% (92.8 to 95.1). Triplex US had pooled sensitivity of 96.4% (94.4 to 97.1%) for proximal DVT, 75.2% (67.7 to 81.6) for distal DVT and specificity of 94.3% (92.5 to 95.8). Compression US alone had pooled sensitivity of 93.8 % (92.0 to 95.3%) for proximal DVT, 56.8% (49.0 to 66.4) for distal DVT and specificity of 97.8% (97.0 to 98.4). Sensitivity was higher in more recently published studies and in cohorts with higher prevalence of DVT and more proximal DVT, and was lower in cohorts that reported interpretation by a radiologist. Specificity was higher in cohorts that excluded patients with previous DVT. No studies were identified that compared repeat US to venography in all patients. Repeat US appears to have a positive yield of 1.3%, with 89% of these being confirmed by venography.

CONCLUSION

Combined colour-doppler US techniques have optimal sensitivity, while compression US has optimal specificity for DVT. However, all estimates are subject to substantial unexplained heterogeneity. The role of repeat scanning is very uncertain and based upon limited data.

Variation in the diagnostic performance of D-dimer for suspected deep vein thrombosis

BACKGROUND

Numerous studies have evaluated the accuracy of D-dimer in diagnosing suspected deep vein thrombosis (DVT), but results are conflicting.

AIM

To overview estimates of the diagnostic accuracy of D-dimer and identify causes of variation.

DESIGN

Systematic review, meta-analysis and meta-regression.

METHODS

We searched Medline, EMBASE, CINAHL, Web of Science, Cochrane Database of Systematic Reviews, Cochrane Controlled Trials Register, Database of Reviews of Effectiveness, the ACP Journal Club, citation lists, and contacted manufacturers. We selected studies that compared D-dimer to a reference standard in patients with suspected DVT. Data were analysed by random effects meta-analysis and meta-regression.

RESULTS

We included 97 studies reporting 198 assays in 99 different patient groups. Overall estimated sensitivity and specificity of D-dimer were 90.5% and 54.7%, but both estimates were subject to significant heterogeneity (p < 0.001). Meta-regression identified that some heterogeneity was explained by study setting, exclusion criteria, whether recruitment was consecutive or the study prospective, whether D-dimer and the reference standard were measured blind, and whether the D-dimer threshold was determined a priori. Sensitivity and specificity also varied between ELISA (94% and 45% respectively), latex (89% and 55%) and whole blood agglutination assays (87% and 68%). Sensitivity was higher for proximal than distal DVT. Specificity was dependent upon whether clinical probability of DVT was high (specificity 51%), intermediate (67%) or low (78%).

DISCUSSION

D-dimer has good sensitivity, but poor specificity, for DVT. Estimates are subject to substantial heterogeneity from various sources. D-dimer specificity appears to be strongly dependent upon the pre-test clinical probability of DVT.

Combined use of rapid D-dimer testing and estimation of clinical probability in the diagnosis of deep vein thrombosis: systematic review

OBJECTIVE

To summarise the evidence supporting the use of rapid d-dimer testing combined with estimation of clinical probability to exclude the diagnosis of deep venous thrombosis among outpatients.

DATA SOURCES

Medline (June 1993 to December 2003), the Database of Abstracts and Reviews (DARE), and reference lists of studies in English.

SELECTION OF STUDIES

We selected 12 studies from among 84 reviewed. The selected studies included more than 5000 patients and used a rapid D-dimer assay and explicit criteria to classify cases as having low, intermediate, or high clinical probability of deep vein thrombosis of the lower extremity among consecutive outpatients.

REVIEW METHODS

Diagnosis required objective confirmation, and untreated patients had to have at least three months of follow up. The outcome was objectively documented venous thromboembolism. Two authors independently abstracted data by using a data collection form.

RESULTS

When the less sensitive SimpliRED D-dimer assay was used the three month incidence of venous thromboembolism was 0.5% (95% confidence interval 0.07% to 1.1%) among patients with a low clinical probability of deep vein thrombosis and normal D-dimer concentrations. When a highly sensitive D-dimer assay was used, the three month incidence of venous thromboembolism was 0.4% (0.04% to 1.1%) among outpatients with low or moderate clinical probability of deep vein thrombosis and a normal D-dimer concentration.

CONCLUSIONS

The combination of low clinical probability for deep vein thrombosis and a normal result from the SimpliRED D-dimer test safely excludes a diagnosis of acute venous thrombosis A normal result from a highly sensitive D-dimer test effectively rules out deep vein thrombosis among patients classified as having either low or moderate clinical probability of deep vein thrombosis.