Toward a uniform pathway in managing incidental lung nodules on computerised tomography [CT] coronary angiography; for a cost effective and safe outcome
Authors: Kanthasamy V , Mahmood A , Karde S , Mason S , Marshall A , Reddy R , Sallomi D , Veasey R , Patel N 
Published: November 2020

Abstract

Background
National Institute for Health and Care Excellence guidelines (NICE CG95) recommends computed tomography coronary angiography [CTCA] as the first line investigation for all patients with suspected typical or atypical angina irrespective of pre-test probability due to its excellent performance and cost effectiveness. However previous cost effectiveness analyses have not factored in the burden of lung nodules [LN] or extracardiac incidentalomas, which are commonly identified on CTCA.

Purpose
As we increasingly detect LN on CTCA scans, it is prudent that a uniform pathway is followed for surveillance of LN. The British Thoracic Society (BTS) has enabled evidence-based development of an algorithm for the management of LN which defines a cut off LN size of ≥5mm requiring further follow up. We aimed to assess the compliance of LN follow up in our patients according to radiology recommendation on CTCA reports and also to assess how well these recommendations adhere to BTS guidelines.

Method
117 patients who underwent CTCA as the initial diagnostic investigation were retrospectively identified from the rapid access chest pain clinic database. Data was collected during a 1 year period between January - December 2017. Data was analysed to determine whether appropriate surveillance pathway was followed for repeat imaging. According to BTS guidelines, nodules ≥5mm should have a systematic work up for surveillance and hence we have stratified our data based on the nodule size. In case of multiple nodules, the largest nodule size was considered.

Results
Out of 117 patients, 77% patients were female with average age 57.8±9.0 years. 40% patients were found to have incidental LN with an average size of 4.63±1.92mm; 44% had a history of cigarette smoking.
Among patient with nodules, 22 (19%) had CT thorax to assess interval change and interestingly 16 (73%) had persisting LN; whereas in 4 (18%), the LN resolved and only 2 (9%) showed increase in LN size. Repeat CT chest was advised for these 2 patients; 1 was advised to undergo biopsy which eventually ruled out malignancy. 6 patients (5%) from group 1 were recommended for repeat CT despite having LN size &lt;5mm.
In the remaining 25 patients (21%) with LN, 15 (60%) did not have further surveillance imaging even though this was recommended by the reporting radiologist. Of these only 3 (12%) had LN ≥5mm which qualified for surveillance CT.

Conclusion
CTCA frequently detects incidentalomas especially LN which cannot be overlooked and require further imaging irrespective of the primary presentation. Our findings also suggest a discrepancy on surveillance CT recommendation against the current BTS guidelines, with potential significant impact on the overall cost effectiveness of CTCA. A systematic approach to LN surveillance could be best achieved with a multidisciplinary team approach (e.g. referral pathway to nodule MDT) and adherence to a standard guideline.
Lung nodule surveillance following CTCA

Funding Acknowledgement
Type of funding source: None