PURPOSE: The Computed Tomography Pulmonary Angiogram (CTPA) is widely used for detection of pulmonary embolism. However, radiation exposure and risk from dye (both allergic and nephrotoxic) are issues that must be considered prior to ordering the test. In the emergency department setting, the Well’s Score has been well established in predicting the likelihood of venous thromboembolism. When combined with a negative d-dimer, CTPA can be avoided in patients with a low-risk Well’s score. The present study evaluates usage of the Well’s Score and d-dimer in patients who underwent CTPA.
METHODS: Data were collected from randomly selected charts of patients who underwent CTPA between July 1, 2004-June 30, 2005. Data obtained from patients included age, sex, indication for CTPA, d-dimer, vital signs, information for modified Well’s Score, and results of CTPA.
RESULTS: 205 charts were reviewed. 15% of cases had a low Well’s Score (4 or less) with a negative d-dimer, indicating that the CTPA may have been unnecessary. 92 patients had d-dimer tests performed, and of the 31 patients with a negative d-dimer, 0 had a pulmonary embolus. 100 patients had a CTPA with a low Well’s Scores (4 or less) and but no D-dimer, indicating that if a d-dimer were drawn in these cases, some would be negative and further CTPA usage could have been curtailed. In some of these cases, it may have been deemed unsafe to order and wait for d-dimer testing prior to CTPA. No patients required hemodialysis for contrast-induced nephrotoxicity treatment.
CONCLUSION: This present study adds to current literature regarding the safety of withholding CTPA in the setting of a low risk Well’s Score with a concomitantly negative d-dimer, even when a latex agglutination d-dimer test is used.
CLINICAL IMPLICATIONS: The current study emphasizes the need for continued education on the validity of the Well’s criteria and d-dimer in safely excluding pulmonary embolism. The absence of contrast nephropathy in these 205 patients in an urban teaching hospital is reassuring.
DISCLOSURE: Jason Mohr, No Financial Disclosure Information; No Product/Research Disclosure Information