Re: When a test is too good: how CT pulmonary angiograms find pulmonary emboli that do not need to be found
We read with interest the recent paper by Renda Soylemez Wiener et al in the Journal (1). We share with these authors bewilderment at the excessive use of CT angiography (CTA) in the emergency department to rule out pulmonary embolism (PE). Many of these CTs are negative, patients are unnecessary exposed to radiation, and costly procedures and precious time are wasted.
A contributory factor to the exaggerated performance of this procedure is related to the liberal use of D Dimers test, an established method to rule out venous thromboembolism. As raised D dimer values are frequently observed, the next step by the attending physician is to perform CTA (Am J Med).
In a recent preliminary evaluation of this problem at our hospital, most of the CTA performed in the emergency department to rule out PE were negative. A small proportion showed minimal findings compatible with small infarctions and these patients were treated accordingly with anticoagulant therapy. Our findings further confirms the magnitude of the problem (1,2).
As Rubin ED remarked more than 40 years ago (Rubin ref), pulmonary embolism is overdiagnosed and overtreated (3). The current paper by Renda Soylemez Wiener, et al, shows us that not only is PE overdiagnosed but many diagnosed cases are subclinical and may not need therapy. This is a relative new issue that needs to be considered when confronting a patient with PE and minimal positive findings on imaging. Should we postpone therapy? Should we use less sensitive imaging modalities and come back to VQ scans? These are relevant questions considering the high morbidity and mortality secondary to anticoagulants administration. CTA is an important imaging tool and is effective for diagnosis of PE, but overdiagnosis is an undesirable effect. Regarding CTA for PE should we ask ourselves, once more if "..the emperor has no clothes.."?.
References
1. Wiener RS, Schwartz LM, Woloshin S. When a test is too good: how CT pulmonary angiograms find pulmonary emboli that do not need to be found. BMJ 2013;347 (f3368): 1-7.
2. Adams DM, Stevens SM, Woller SC, Evans RS, Lloyd JF, Snow GL, Adherence to PIOPED II Investigators. Recommendations for Computed Tomography Pulmonary Angiography. Am J Med. 2013:126:36-42.
3. Robin ED. Overdiagnosis and overtreatment of pulmonary embolism: the emperor may have no clothes. Ann Intern Med. 1977;87(6):775-81.
Competing interests:
No competing interests
24 July 2013
Arie Markel
physician-internal medicine
Tzadok (last name) Bat Sheva (first name)
Haemek Medical Center-Afula, Israel, associated to the Technion, Faculty of Medicine, Haifa, Israel.
Rapid Response:
Re: When a test is too good: how CT pulmonary angiograms find pulmonary emboli that do not need to be found
We read with interest the recent paper by Renda Soylemez Wiener et al in the Journal (1). We share with these authors bewilderment at the excessive use of CT angiography (CTA) in the emergency department to rule out pulmonary embolism (PE). Many of these CTs are negative, patients are unnecessary exposed to radiation, and costly procedures and precious time are wasted.
A contributory factor to the exaggerated performance of this procedure is related to the liberal use of D Dimers test, an established method to rule out venous thromboembolism. As raised D dimer values are frequently observed, the next step by the attending physician is to perform CTA (Am J Med).
In a recent preliminary evaluation of this problem at our hospital, most of the CTA performed in the emergency department to rule out PE were negative. A small proportion showed minimal findings compatible with small infarctions and these patients were treated accordingly with anticoagulant therapy. Our findings further confirms the magnitude of the problem (1,2).
As Rubin ED remarked more than 40 years ago (Rubin ref), pulmonary embolism is overdiagnosed and overtreated (3). The current paper by Renda Soylemez Wiener, et al, shows us that not only is PE overdiagnosed but many diagnosed cases are subclinical and may not need therapy. This is a relative new issue that needs to be considered when confronting a patient with PE and minimal positive findings on imaging. Should we postpone therapy? Should we use less sensitive imaging modalities and come back to VQ scans? These are relevant questions considering the high morbidity and mortality secondary to anticoagulants administration. CTA is an important imaging tool and is effective for diagnosis of PE, but overdiagnosis is an undesirable effect. Regarding CTA for PE should we ask ourselves, once more if "..the emperor has no clothes.."?.
References
1. Wiener RS, Schwartz LM, Woloshin S. When a test is too good: how CT pulmonary angiograms find pulmonary emboli that do not need to be found. BMJ 2013;347 (f3368): 1-7.
2. Adams DM, Stevens SM, Woller SC, Evans RS, Lloyd JF, Snow GL, Adherence to PIOPED II Investigators. Recommendations for Computed Tomography Pulmonary Angiography. Am J Med. 2013:126:36-42.
3. Robin ED. Overdiagnosis and overtreatment of pulmonary embolism: the emperor may have no clothes. Ann Intern Med. 1977;87(6):775-81.
Competing interests: No competing interests