Abstract

The D-dimer assay’s ability to exclude pulmonary thromboembolism (PTE) falls with age.1,2 Douma et al. have proposed an age-adjusted D-dimer threshold ([threshold, μg/l] = [age, years] x 10) for patients aged >50 years with low clinical risk of PTE.3 We retrospectively applied this threshold to patients who underwent computer tomographic pulmonary angiogram (CTPA) for suspected PTE during a 13 month period at a busy District General Hospital. Of the 423 patients >50 years old who underwent CTPA, 22 (5.2%) had D-dimer concentrations higher than the traditional threshold but lower than the age-adjust threshold, none of whom had evidence of PTE on CTPA. This suggests that use of the age-adjusted D-dimer threshold may reduce necessity for CTPA concept patients aged >50 years.

[download-attachments container="div" style="list" display_icon="1" display_count="1" display__size="0"]

 

References

1. Hager K, Platt D. Fibrin degredation product concentrations (D-dimers) in the course of ageing. Gerontology 1995; 41: 159–65.
2. Righini M, Goehring C, Bounameaux H, et al. Effects of age on the performance of common diagnostic tests for pulmonary embolism. AM J Med 2000; 109: 357–61.
3. Douma RA, le Gal G, Söhne M, et al. Potential of an age-adjusted D-dimer cut-off value to improve the exclusion of pulmonary embolism in older patients: a retrospective analysis of three large cohorts. BMJ 2010; 340: c1475.
4. Sanson BJ, Lijmer JG, Mac Gillavry MR, et al. Comparison of a clinical probability estimate and two clinical models in patients with suspected pulmonary embolism. Thromb Haemost 2000; 83(2): 199–203.
5. Schellhaass A, Walther A, Konstantinides S, et al. The diagnosis and treatment of acute pulmonary embolism. Dtsch Arztebl Int 2010; 107(34-35): 589–95.
6. Pulmonary Embolism Guideline Development Group; BTS Guidelines for the Management of Suspected Acute Pulmonary Embolism. Thorax 2003; 58: 470–48.
7. Becker DE, Philbrick JT, Bachhuber TL, et al. D-dimer testing and acute venous thromboembolism: a shortcut to accurate diagnosis? Arch Intern Med 1996; 156: 939–946.
8. Bounameaux H, de Moerloose P, Perrier A, et al. Plasma measurement of D-dimer as diagnostic aid in suspected venous thromboembolism: an overview. Thromb Haemost 1994; 71: 1–6.
9. Bayes HK, O’Dowd CA, Glassford NJ, et al. D-dimer assays--a help or hindrance in suspected pulmonary thromboembolism assessment? J Postgrad Med 2011; 57(2): 109–14.
10. Moores LK, Jackson WL, Shorr AF, et al. Meta-Analysis: outcomes in patients with suspected pulmonary embolism managed with computed tomographic pulmonary angiography. Ann Intern Med 2004; 141(11): 866–874.
11. Goldhaber SZ. Pulmonary embolism. Lancet 2004; 363(9417): 1295–305.
12. Righini M, Bounameaux H. Diagnosing pulmonary embolism in elderly patients: a difficult challenge. Bellia V, Antonelli Incalzi R, editors: Respiratory Diseases in the Elderly. European Respiratory Society Monograph 2009; 43: 163–78.
13. University Hospital, Geneva [online]. Age-adjusted D-dimer Cut-off Levels to Rule Out Pulmonary Embolism (ADJUST). ClinicalTrials.gov, National Institutes of health 2010. URL: http://clinicaltrials.gov/ct2/show/NCT01134068 (Last accessed: 27/02/2012)