Audit of Computed Tomographic Angiograms for Pulmonary Embolism in a Regional Hospital in Hong Kong

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EMW Man, SY Luk, CS Cheng

Hong Kong J Radiol 2010;13:68-72

Objective: To audit requests for computed tomographic pulmonary angiograms, usage of pre-test pulmonary embolism probability scores, and D-dimer measurements in patients with suspected pulmonary embolism in aregional hospital in Hong Kong.

Methods: A retrospective study was performed for all computed tomographic pulmonary angiograms requested for clinically suspicious pulmonary embolism during the period of 1 January 2008 to 31 December 2008. Clinical notes were reviewed and patients were being included or excluded according to predefined inclusion and exclusion criteria.

Results: Of the 109 cases of computed tomographic pulmonary angiogram requests (after excluding 12), there were 25 who had pulmonary embolism. The percentage of computed tomographic pulmonary angiograms positive for pulmonary embolism was 23%. Not any documented standardised pre-test pulmonary embolism probability score was noted. D-dimer tests were performed in 27 cases, however, most of these requested tests were not performed according to 2003 British Thoracic Society guidelines.

Conclusion: There was a nearly 5-fold increase in requests for computed tomographic pulmonary angiograms for suspected pulmonary embolism over a 4-year period (2004 vs 2008). In our audit, the percentage reported positive was 23%, which was lower than most diagnostic study series in which the reported prevalence ranged from 28 to 33%. Reasons for this are multifactorial and may include a lower overall prevalence of pulmonary embolism in Chinese patients and speculations about ineffective patient selection by referring physicians. The latter possibility was supported by the observation that there was no documented use of any standardised pre-test pulmonary embolism probability score in our 109 cases. The audit also suggested misuse of D-dimer tests, which can be improved if the referring physicians were more aware of the sensitivity and the limitations of such tests.