BMJ  2006;332:364 (11 February), doi:10.1136/bmj.332.7537.364

Letter

Venous thromboembolism

Potentially dangerous diagnostic pitfalls arise from diagnostic tests

EDITOR—The review of venous thromboembolism by Blanna and Lip did not draw sufficient attention to the diagnostic pitfalls that are an almost inevitable consequence of the reliance that many frontline medical staff place on diagnostic tests when differentiating between three of the most life threatening chest pain syndromes.¹ These I would call the three ugly sisters—namely, pulmonary embolism, dissecting aortic aneurysm, and myocardial infarction.

Credit: JAMES KING HOLMES/SPL

 

Dissecting aneurysm simulates pulmonary embolism when it presents with chest pain and/or collapse in association with raised d-dimer concentrations of the order of > 0.5 µg/ml, so much so that "testing for d-dimer should be part of the initial assessment of patients with chest pain, especially if aortic dissection is suspected."² When pulmonary embolism presents with chest pain and raised serum cardiac troponin³ a mistaken diagnosis of myocardial infarction might lead not only to inappropriate thrombolysis but also to a false sense of security given the likelihood that in that context, thrombolytic treatment will not be followed by a course of oral anticoagulation lasting at least three months as recommended by Blann and Yip.¹

The reality is that, such is the overlap in the symptoms of the three ugly sisters that, to paraphrase the authors of a recent study evaluating the limitations of a chest pain history, none of the elements of the chest pain history, alone or in combination, identify a group of patients that can be safely categorised without further diagnostic testing.⁴ If, as in the real world, a patient with chest pain enters the diagnostic algorithm on the basis of the d-dimer test, even when pulmonary embolism is deemed unlikely,⁵ or on the basis of troponinosis, even where myocardial infarction is deemed unlikely, the consequences will be incalculable unless these diagnostic pitfalls are highlighted.

Manchester M20 2RN oscarjolobe{at}yahoo.co.uk

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Competing interests: None declared.

References

1. Blann AD, Lip GYH. Venous thromboembolism. BMJ 2006;332: 215-9. (28 January.)[Free Full Text]
2. Weber T, Hogler S, Auer J, et al. D-dimer in acute aortic dissection. Chest 2003;123: 1375-8.[Abstract/Free Full Text]
3. Francis GS, Tang WHW. Cardiac troponins in renal insufficiency and other non-ischemic cardiac conditions. Prog Cardiovasc Dis 2004;47: 196-206.[CrossRef][ISI][Medline]
4. Swap CJ, Nagurney JT. Value and limitations of chest pain history in the evaluation of patients with suspected acute coronary syndromes. JAMA 2005;294: 2623-9.[Abstract/Free Full Text]
5. Writing Group for the Christopher Study Investigators. Effectiveness of managing suspected pulmonary embolism using an algorithm combining clinical probability, D-Dimer testing, and computer tomography. JAMA 2006;295: 172-9.[Abstract/Free Full Text]

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Venous thromboembolism

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