Adherence to PIOPED II investigators' recommendations for computed tomography pulmonary angiography

Computed tomography (CT) pulmonary angiography use has increased dramatically, raising concerns for patient safety. Adherence to recommendations and guidelines may protect patients. We measured adherence to the recommendations of Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED II) investigators for evaluation of suspected pulmonary embolism and the rate of potential false-positive pulmonary embolism diagnoses when recommendations of PIOPED II investigators were not followed.

We used a structured record review to identify 3500 consecutive CT pulmonary angiograms performed to investigate suspected pulmonary embolism in 2 urban emergency departments, calculating the revised Geneva score (RGS) to classify patients as "pulmonary embolism unlikely" (RGS≤10) or "pulmonary embolism likely" (RGS>10). CT pulmonary angiograms were concordant with PIOPED II investigator recommendations if pulmonary embolism was likely or pulmonary embolism was unlikely and a highly sensitive D-dimer test result was positive. We independently reviewed 482 CT pulmonary angiograms to measure the rate of potential false-positive pulmonary embolism diagnoses.

A total of 1592 of 3500 CT pulmonary angiograms (45.5%) followed the recommendations of PIOPED II investigators. The remaining 1908 CT pulmonary angiograms were performed on patients with an RGS≤10 without a D-dimer test (n=1588) or after a negative D-dimer test result (n=320). The overall rate of pulmonary embolism was 9.7%. Potential false-positive diagnoses of pulmonary embolism occurred in 2 of 3 patients with an RGS≤10 and a negative D-dimer test result.

Nonadherence to recommendations for CT pulmonary angiography is common and exposes patients to increased risks, including potential false-positive diagnoses of pulmonary embolism.