Objectives. We conducted a study to answer 3 questions: (1) is CT pulmonary angiography (CTPA) overutilized in suspected pulmonary embolism (PE)? (2) What alternative diagnoses are provided by CTPA? (3) Can CTPA be used to evaluate right ventricular dilatation (RVD)? Methods. We retrospectively reviewed the clinical information of 231 consecutive emergency department patients who underwent CTPA for suspected PE over a one-year period. Results. The mean age of our patients was 53 years, and 58.4% were women. The prevalence of PE was 20.7%. Among the 136 patients with low clinical probability of PE, a d-dimer test was done in 54.4%, and it was normal in 24.3%; none of these patients had PE. The most common alternative findings on CTPA were emphysema (7.6%), pneumonia (7%), atelectasis (5.5%), bronchiectasis (3.8%), and congestive heart failure (3.3%). The sensitivity and negative predictive value of CTPA for (RVD) was 92% and 80%, respectively. Conclusions. PE could have been excluded without CTPA in ~1 out of 4 patients with low clinical probability of PE, if a formal assessment of probability and d-dimer test had been done. In patients without PE, CTPA did not provide an alternative diagnosis in 65%. In patients with PE, CTPA showed the potential to evaluate RVD. 1. Introduction The paradox in the diagnosis of pulmonary embolism (PE) is that it tends to be both underdiagnosed and overinvestigated. The prevalence of PE-varies from 10% to 25% in different studies [1–5]. The vast majority (94%) of PE related deaths are because of a failure of diagnosis [6]. The consequences of missing the diagnosis and the ease of recalling prior serious cases may lead to an overestimation of the probability of PE and lower the threshold for initiating a cascade of diagnostic testing, a phenomenon described as the availability heuristics in cognitive psychology [7, 8]. The widespread round-the-clock availability, excellent accuracy [9, 10] of CT pulmonary angiography (CTPA), and ability to provide an alternative diagnosis [11, 12] may further lower the threshold for performing this imaging study and result in its overuse. On the other hand, outcome studies using clinical prediction rules to refine diagnostic certainty have shown that PE can be safely excluded in patients with low clinical probability and normal d-dimer levels without an imaging study [1, 2, 5]. However, the impact of such evidence-based strategies on actual clinical practice is not known. In this era of evidence-based decision making and cost-effective utilization of resources, it is imperative to diagnose
References
[1]
P. S. Wells, D. R. Anderson, M. Rodger et al., “Excluding pulmonary embolism at the bedside without diagnostic imaging: management of patients with suspected pulmonary embolism presenting to the emergency department by using a simple clinical model and D-dimer,” Annals of Internal Medicine, vol. 135, no. 2, pp. 98–107, 2001.
[2]
M. J. H. A. Kruip, M. J. Slob, J. H. E. M. Schijen, C. van der Heul, and H. R. Büller, “Use of a clinical decision rule in combination with D-dimer concentration in diagnostic workup of patients with suspected pulmonary embolism: a prospective management study,” Archives of Internal Medicine, vol. 162, no. 14, pp. 1631–1635, 2002.
[3]
I. Chagnon, H. Bounameaux, D. Aujesky et al., “Comparison of two clinical prediction rules and implicit assessment among patients with suspected pulmonary embolism,” The American Journal of Medicine, vol. 113, no. 4, pp. 269–275, 2002.
[4]
S. J. Wolf, T. R. McCubbin, K. M. Feldhaus, J. P. Faragher, and D. M. Adcock, “Prospective validation of wells criteria in the evaluation of patients with suspected pulmonary embolism,” Annals of Emergency Medicine, vol. 44, no. 5, pp. 503–510, 2004.
[5]
A. van Belle, H. R. Büller, M. V. Huisman, P. M. Huisman, et al., “Effectiveness of managing suspected pulmonary embolism using an algorithm combining clinical probability, D-dimer testing, and computed tomography,” Journal of the American Medical Association, vol. 295, no. 2, pp. 172–179, 2006.
[6]
J. E. Dalen, “Pulmonary embolism: what have we learned since Virchow? Natural history, pathophysiology, and diagnosis,” Chest, vol. 122, no. 4, pp. 1440–1456, 2002.
[7]
S. Iles, L. Beckert, M. Than, and G. I. Town, “Making a diagnosis of pulmonary embolism: new methods and clinical issues,” New Zealand Medical Journal, vol. 116, no. 1177, 2003.
[8]
H. C. Sox, M. A. Blatt, M. C. Higgins, et al., Medical Decision Making, Butterworth-Heineman, Woburn, Mass, USA, 1988.
[9]
L. K. Moores, W. L. Jackson Jr., A. F. Shorr, and J. L. Jackson, “Meta-analysis: outcomes in patients with suspected pulmonary embolism managed with computed tomographic pulmonary angiography,” Annals of Internal Medicine, vol. 141, no. 11, pp. 866–874, 2004.
[10]
R. Quiroz, N. Kucher, K. H. Zou et al., “Clinical validity of a negative computed tomography scan in patients with suspected pulmonary embolism: a systematic review,” Journal of the American Medical Association, vol. 293, no. 16, pp. 2012–2017, 2005.
[11]
M. J. L. van Strijen, J. L. Bloem, W. de Monye et al., “Helical computed tomography and alternative diagnosis in patients with excluded pulmonary embolism,” Journal of Thrombosis and Haemostasis, vol. 3, no. 11, pp. 2449–2456, 2005.
[12]
K.-L. Tsai, E. Gupta, and L. B. Haramati, “Pulmonary atelectasis: a frequent alternative diagnosis in patients undergoing CT-PA for suspected pulmonary embolism,” Emergency Radiology, vol. 10, no. 5, pp. 282–286, 2004.
[13]
P. S. Wells, D. R. Anderson, M. Rodger et al., “Derivation of a simple clinical model to categorize patients probability of pulmonary embolism: increasing the models utility with the SimpliRED D-dimer,” Thrombosis and Haemostasis, vol. 83, no. 3, pp. 416–420, 2000.
[14]
K.-E. Lim, C.-Y. Chan, P.-H. Chu, Y.-Y. Hsu, and W.-C. Hsu, “Right ventricular dysfunction secondary to acute massive pulmonary embolism detected by helical computed tomography pulmonary angiography,” Clinical Imaging, vol. 29, no. 1, pp. 16–21, 2005.
[15]
M. A. Rodger, E. Maser, I. Stiell, H. E. A. Howley, and P. S. Wells, “The interobserver reliability of pretest probability assessment in patients with suspected pulmonary embolism,” Thrombosis Research, vol. 116, no. 2, pp. 101–107, 2005.
[16]
S. Iles, A. M. Hodges, J. R. Darley et al., “Clinical experience and pre-test probability scores in the diagnosis of pulmonary embolism,” Monthly Journal of the Association of Physicians, vol. 96, no. 3, pp. 211–215, 2003.
[17]
J. Wicki, T. V. Perneger, A. F. Junod, H. Bounameaux, and A. Perrier, “Assessing clinical probability of pulmonary embolism in the emergency ward: a simple score,” Archives of Internal Medicine, vol. 161, no. 1, pp. 92–97, 2001.
[18]
G. Waser, S. Kathriner, and W. A. Wuillemin, “Performance of the automated and rapid STA Liatest D-dimer on the STA-R analyzer,” Thrombosis Research, vol. 116, no. 2, pp. 165–170, 2005.
[19]
R. E. G. Schutgens, F. J. L. M. Haas, W. B. M. Gerritsen, F. van der Horst, H. K. Nieuwenhuis, and D. H. Biesma, “The usefulness of five D-dimer assays in the exclusion of deep venous thrombosis,” Journal of Thrombosis and Haemostasis, vol. 1, no. 5, pp. 976–981, 2003.
[20]
S. Namasivayam, M. K. Kalra, W. E. Torres, and W. C. Small, “Adverse reactions to intravenous iodinated contrast media: a primer for radiologists,” Emergency Radiology, vol. 12, no. 5, pp. 210–215, 2006.
[21]
M. S. Parker, F. K. Hui, M. A. Camacho, J. K. Chung, D. W. Broga, and N. N. Sethi, “Female breast radiation exposure during CT pulmonary angiography,” The American Journal of Roentgenology, vol. 185, no. 5, pp. 1228–1233, 2005.
[22]
L. M. Hurwitz, T. Yoshizumi, R. E. Reiman et al., “Radiation dose to the fetus from body MDCT during early gestation,” The American Journal of Roentgenology, vol. 186, no. 3, pp. 871–876, 2006.
[23]
A. Berrington de González, M. Mahesh, K.-P. Kim et al., “Projected cancer risks from computed tomographic scans performed in the United States in 2007,” Archives of Internal Medicine, vol. 169, no. 22, pp. 2071–2077, 2009.
[24]
D. J. Brenner and E. J. Hall, “Computed tomography: an increasing source of radiation exposure,” The New England Journal of Medicine, vol. 357, no. 22, pp. 2277–2284, 2007.
[25]
A. Sodickson, P. F. Baeyens, K. P. Andriole et al., “Recurrent CT, cumulative radiation exposure, and associated radiation-induced cancer risks from CT of adults,” Radiology, vol. 251, no. 1, pp. 175–184, 2009.
[26]
H. T. Winer-Muram, J. M. Boone, H. L. Brown, S. G. Jennings, W. C. Mabie, and G. T. Lombardo, “Pulmonary embolism in pregnant patients: fetal radiation dose with helical CT,” Radiology, vol. 224, no. 2, pp. 487–492, 2002.
[27]
J.-A. Lee, B. K. Zierler, C.-F. Liu, and M. K. Chapko, “Cost-effective diagnostic strategies in patients with a high, intermediate, or low clinical probability of pulmonary embolism,” Vascular and Endovascular Surgery, vol. 45, no. 2, pp. 113–121, 2011.
[28]
S. Grifoni, I. Olivotto, P. Cecchini et al., “Short-term clinical outcome of patients with acute pulmonary embolism, normal blood pressure, and echocardiographic right ventricular dysfunction,” Circulation, vol. 101, no. 24, pp. 2817–2822, 2000.
[29]
N. Mansencal, T. Joseph, A. Vieillard-Baron et al., “Diagnosis of right ventricular dysfunction in acute pulmonary embolism using helical computed tomography,” The American Journal of Cardiology, vol. 95, no. 10, pp. 1260–1263, 2005.
[30]
A. Ghuysen, B. Ghaye, V. Willems et al., “Computed tomographic pulmonary angiography and prognostic significance in patients with acute pulmonary embolism,” Thorax, vol. 60, no. 11, pp. 956–961, 2005.
[31]
W. Kasper, S. Konstantinides, A. Geibel, N. Tiede, T. Krause, and H. Just, “Prognostic significance of right ventricular afterload stress detected by echocardiography in patients with clinically suspected pulmonary embolism,” Heart, vol. 77, no. 4, pp. 346–349, 1997.
[32]
S. Z. Goldhaber, W. D. Haire, M. L. Feldstein et al., “Alteplase versus heparin in acute pulmonary embolism: randomised trial assessing right-ventricular function and pulmonary perfusion,” The Lancet, vol. 341, no. 8844, pp. 507–511, 1993.
[33]
A. Ribeiro, P. Lindmarker, A. Juhlin-Dannfelt, H. Johnsson, and L. Jorfeldt, “Echocardiography Doppler in pulmonary embolism: right ventricular dysfunction as a predictor of mortality rate,” The American Heart Journal, vol. 134, no. 3, pp. 479–487, 1997.
[34]
O. Sanchez, L. Trinquart, I. Colombet et al., “Prognostic value of right ventricular dysfunction in patients with haemodynamically stable pulmonary embolism: a systematic review,” European Heart Journal, vol. 29, no. 12, pp. 1569–1577, 2008.
[35]
G. Coutance, E. Cauderlier, J. Ehtisham, M. Hamon, and M. Hamon, “The prognostic value of markers of right ventricular dysfunction in pulmonary embolism: a meta-analysis,” Critical Care, vol. 15, no. 2, article R103, 2011.
