Incidental pulmonary nodules in emergent coronary CT angiography for suspected acute coronary syndrome: Impact of revised 2017 Fleischner Society Guidelines

Abstract

Background: Pulmonary nodules (PN) are frequently detected incidentally during coronary computed tomography angiography (CTA). We evaluated whether the 2017 Fleischner Society guidelines may result in a decrease of follow-up testing of incidental PN as compared to prior guidelines in patients undergoing coronary CTA.

Methods: We conducted a retrospective study of a registry of emergency department patients who underwent coronary CTA for acute coronary syndrome assessment between 2012 and 2017. Based on guidelines, patients <35 years, history of cancer, or prior exams showing stability of PN were excluded. Patients >60 years, history of smoking, irregular/spiculated PN morphology, or PN size >20 mm were classified as high-risk for lung cancer. Radiological findings pertaining to PN were identified (PN size, morphology, quantity) through review of radiology reports. PN follow-up recommendations were established using 2017 Fleischner Society Guidelines and compared with prior guidelines for solid (2005) and subsolid (2013) PN. Data were analyzed with Student's t-test.

Results: The registry included 2066 patients (female 45.1%, 52.9 ± 11.0 years), of which 578 (28.0%) reported PN. 438 of those (21.2%) were eligible for guideline-based follow-up evaluation. 205 (4 6.8%) were classified as high-risk for lung cancer. 2017 guidelines reduced the number of individuals requiring follow-up by 64.5%, from 264 (12.8%) to 94 patients (4.5%) when compared to prior guidelines (p < 0.001). The minimum number of follow-up chest CTs decreased by 55.8% from 430 to 190 (p < 0.001).

Conclusion: Application of the 2017 Fleischner Society Guidelines resulted in a significant decrease of follow-up testing for incidental PN in patients undergoing coronary CTA for suspected acute coronary syndrome.

Keywords: Acute coronary syndrome; Coronary computed tomography angiography; Fleischner Society Guidelines; Follow-up CT; Incidental findings; Lung nodule; Management of incidental lung nodules; Pulmonary nodule.

Fig 1

62-year-old female presented with acute chest pain to the emergency department. Coronary CT angiography ruled out coronary artery disease. Reconstructed maximum field-of-view axial 3-mm-thick maximum intensity projection (MIP) images revealed a single 5-mm solid pulmonary nodule in the middle lobe (top image). Average of long and short axes were measured in 1.5 mm multiplanar reformations (MPR) and rounded to the nearest millimeter (bottom images). She was considered low-risk for lung cancer and therefore needed no follow-up chest CT per 2017 guidelines. Prior guidelines from 2005 would have recommended follow-up chest CT at 12 months.

Fig 2

Flow chart of patients with incidentally detected pulmonary nodules within the registry of acute chest pain patients who underwent coronary CT angiography.

Fig 3

Patients with recommended follow-ups of incidental pulmonary nodules based on prior (2005 and 2013) and currently revised (2017) Fleischner Society Guidelines compared to all patients, subdivided into coronary artery disease severity.

Fig 4

Patients with incidental pulmonary nodules and need for follow-up testing per prior (2005 and 2013) and revised (2017) Fleischner Society Guidelines subdivided into low and high risk for lung cancer. High risk for lung cancer included history of smoking, age >60 years, upper lobe location of PN, irregular morphology PN, and PN size >20 mm.