Acute pulmonary embolism (PE) is a common and potentially fatal disease. CT angiogram (CTA) of the chest is considered the gold standard diagnostic test for diagnosis of PE. The purpose of this study is to evaluate the appropriate use of an established CTA chest-based diagnostic algorithm in patients with suspected PE presenting to the emergency room (ER) setting.
WWe performed a retrospective review of 259 consecutive patients admitted to our University-affiliated ER who underwent CTA of the chest to rule out PE from January to May 2006. We collected information on demographics, clinical presentation, laboratory and radiographic findings. The pretest clinical probability for PE was calculated using the modified Wells criteria. Data was analyzed using chi square and Fisher's exact for categorical variables and the Student's t test for continuous variables.
Of 259 patients, nine (3.5%) had confirmed acute PE on CTA of the chest. The modified Wells score classified the pretest probability for 231 patients as ‘unlikely’ (4 with PE by CTA) and for 28 as ‘likely’ (5 with PE by CTA). Of patients with an ‘unlikely’ pretest probability, one patient with PE and 107 patients without PE did not undergo D-dimer testing. Thirty nine patients (15.0%) with an ‘unlikely’ pretest probability and a negative D-dimer still underwent CTA chest. Based on our rate of 31.7% likelihood of a negative D-dimer in patients with ‘unlikely’ pretest probability and no PE by CTA chest, 33 additional patients would have avoided CTA chest had D-dimer testing been obtained.
Patients presenting for diagnostic evaluation of PE undergoing CTA chest with pretest probability stratified by the modified Wells criteria were often not evaluated according to an established CTA-based diagnostic algorithm. D-dimer testing was grossly underutilized.
Physicians need to be more aware of the diagnostic algorithm for CTA-based evaluation of PE, which if similar to our study, would result in a significant reduction in testing by CTA chest, reducing the cost of patient care and radiation exposure to patients.
Saif Mashaqi, No Financial Disclosure Information; No Product/Research Disclosure Information