D-dimer for the exclusion of acute venous thrombosis and pulmonary embolism: a systematic review.

BACKGROUND: Despite extensive literature, the diagnostic role of d-dimer for deep venous thrombosis (DVT) or pulmonary embolism (PE) remains unclear, reflecting multiple d-dimer assays and concerns about differing sensitivities and variability. PURPOSE: To systematically review trials that assessed sensitivity, specificity, likelihood ratios, and variability among d-dimer assays. DATA SOURCES: Studies in all languages were identified by searching PubMed from 1983 to January 2003 and EMBASE from 1988 to January 2003. STUDY SELECTION: The researchers selected prospective studies that compared d-dimer with a reference standard. Studies of high methodologic quality were included in the primary analyses; sensitivity analysis included additional weaker studies. DATA EXTRACTION: Two authors collected data on study-level factors: d-dimer assay used, cutoff value, and whether patients had suspected DVT or PE. DATA SYNTHESIS: For DVT, the enzyme-linked immunosorbent assay (ELISA) and quantitative rapid ELISA dominate the rank order for these values: sensitivity, 0.96 (95% confidence limit [CL], 0.91 to 1.00), and negative likelihood ratio, 0.12 (CL, 0.04 to 0.33); and sensitivity, 0.96 (CL, 0.90 to 1.00), and negative likelihood ratio, 0.09 (CL, 0.02 to 0.41), respectively. For PE, the ELISA and quantitative rapid ELISA also dominate the rank order for these values: sensitivity, 0.95 (CL, 0.85 to 1.00), and negative likelihood ratio, 0.13 (CL, 0.03 to 0.58); and sensitivity, 0.95 (CL, 0.83 to 1.00), and negative likelihood ratio, 0.13 (CL, 0.02 to 0.84), respectively. The ELISA and quantitative rapid ELISA have negative likelihood ratios that yield a high certainty for excluding DVT or PE. The positive likelihood values, which are in the general range of 1.5 to 2.5, do not greatly increase the certainty of diagnosis. Sensitivity analyses do not affect these findings. LIMITATIONS: Although many studies evaluated multiple d-dimer assays, findings are based largely on indirect comparisons of test performance characteristics across studies. CONCLUSION: The ELISAs in general dominate the comparative ranking among the d-dimer assays for sensitivity and negative likelihood ratio. For excluding PE or DVT, a negative result on quantitative rapid ELISA is as diagnostically useful as a normal lung scan or negative duplex ultrasonography finding.

Tracking the uptake of evidence: two decades of hospital practice trends for diagnosing deep vein thrombosis and pulmonary embolism.

BACKGROUND: Advances in clinical research methods have led to prospective randomized controlled (level 1) clinical studies evaluating diagnostic modalities resulting in a paradigm shift in the literature for diagnosing deep vein thrombosis (DVT) and pulmonary embolism (PE). To assess whether these advances correlate with clinical practice, we analyzed 21-year trends in diagnostic testing for patients with venous thromboembolism. METHODS: We used discharge data from the National Hospital Discharge Survey (1979-1999) to determine DVT and PE cases annually. Procedure fields were screened to determine patients who had DVT or PE or who underwent venography, arteriography of the pulmonary arteries, pulmonary scintigraphy, or DVT ultrasonic scanning. Searching EMBASE, MEDLINE, and the American Thoracic Society guidelines, a literature-based time line of level 1 studies was derived and juxtaposed against trends and procedure use. RESULTS: Improved diagnostic tests resulted in diagnostic changes in patients with suspected venous thromboembolism. These observed changes correlated over time in subsequent years with level 1 studies. Diagnostic DVT approaches showed an initial marked increased use of venography followed by a rapid decline that coincided with increased use of Doppler ultrasonography. Diagnostic approaches to PE were characterized by initial marked increases in lung scanning followed by a rapid decline as use of ultrasonography considerably increased and pulmonary angiography modestly increased. CONCLUSIONS: Diagnostic approaches to DVT and PE have changed markedly during the past 2 decades, in temporal harmony with the evolving literature. Change in clinical practice occurs over years, and long-term follow-up is required to capture this change.

Deep venous thrombosis in a general hospital.

PURPOSE: To determine the prevalence of proximal deep venous thrombosis (DVT) in a general hospital. BACKGROUND: In spite of the importance of proximal DVT, its prevalence in hospitalized patients has been only sparsely studied. METHODS: Patients hospitalized with DVT between July 1998 and June 2000 were identified by a computer search of discharge diagnoses. The discharge diagnosis was confirmed by a review of the records for positive findings on compression ultrasound or venogram of the lower extremities. In addition, records of all compression ultrasound examinations and venograms during that period were examined. RESULTS: The prevalence of proximal DVT in adults > or = 20 years old was 271 of 34,567 patients (0.78%). DVT was associated with pulmonary embolism in 57 of 271 patients (21.0%). The prevalence of DVT in adult men was 117 of 13,722 patients (0.85%), and in adult women was 154 of 20,845 patients (0.74%) [not significant]. The prevalence of DVT among men aged 20 to 49 years was higher than in women the same age: 19 of 3,982 patients (0.48%) vs 22 of 9,442 patients (0.23%), respectively (p < 0.02). The prevalence of DVT, however, was comparable among men and women > or = 50 years old. The prevalence of DVT was also comparable in black adults (30 of 4,344 patients; 0.69%) and in white adults (240 of 28,615 patients; 0.84%) [not significant]. CONCLUSION: Proximal DVT continues to be a frequent illness among hospitalized patients.

Estimated incidence of acute pulmonary embolism in a community/teaching general hospital.

PURPOSE: This study attempts to determine the incidence of established acute pulmonary embolism (PE) in a community/teaching general hospital. BACKGROUND: The reported incidence of objectively diagnosed acute PE among hospitalized adults in a large urban hospital or major university hospital ranges from 0.27 to 0.40%. Whether the incidence of PE in other categories of hospitals fits within this narrow range is unknown. METHODS: Patients with acute PE diagnosed by ventilation/perfusion lung scan, pulmonary angiography, compression ultrasound in a patient with suspected PE, autopsy, or (by coincidence) lung biopsy were identified among patients hospitalized during a 2-year period from 1998 to 2000. The incidence of PE was also determined according to age, sex, and race. RESULTS: Among adult patients (> or = 20 years old), the incidence of established acute PE was 95 of 34,567 patients (0.27%; 95% confidence interval [CI], 0.22 to 0.34%). No PE was diagnosed in patients < 20 years old. The incidence of PE in men was 36 of 13,722 patients (0.26%; 95% CI, 0.18 to 0.36%); in women, it was 59 of 20,845 patients (0.2%; 95% CI, 0.22 to 0.36%; not significant [NS]). The incidence in African-Americans adults was 10 of 4,344 patients (0.23%; 95% CI, 0.11 to 0.42%); in white adults, it was 84 of 28,615 patients (0.29%; 95% CI, 0.23 to 0.36%; NS). CONCLUSION: The incidence of PE in a community/teaching general hospital was comparable to the incidence in a large urban-care center and in a major university hospital.