In a presentation at the recent the CIRSE 2006 conference, Dr Rao Vallabhaneni, consultant vascular and endovascular surgeon, Royal Liverpool University Hospital, UK, stated that the use of computed tomography (CT) has created the potential for unexpected pathology to be detected on CT examinations.
The research team conducted a study to determine the prevalence of non-aneurysm related findings on CT scans of patients who underwent EVAR in their hospital. The review included a total of 1,435 CT scans belonging to 233 patients, performed during a median follow-up of 34 months, to note findings of non-aneurysm related pathology.
The results revealed a clinically significant and unexpected non-aneurysm related pathology in nearly a third of EVAR patients at some stage. More importantly, 18 patients (8% of the cohort) were noted to have features consistent with a previously unsuspected malignancy and the diagnosis was later confirmed in all but one of them. The cancers detected belonged to urological, biliary, pulmonary, colonic, hepatic and skeletal systems.
According to the researchers, the high prevalence of unexpected and potentially serious pathology, though unsurprising in view of the generally advanced age of the patients, has several implications. First, the need for a methodical and complete assessment of CT images in aneurysm patients should be recognised. Although the focus remains on the arterial system in these patients, the rest of the information available on CT should also be examined by someone with appropriate expertise. Rao commented that this may well mean dual reporting in centres if the specialist assessing the aneurysm does not have the necessary skills to interpret the rest of the picture. It is possible that in some patients, decisions regarding aneurysm treatment might require review if the incidental pathology is associated with poor prognosis.
Second, failure to pick up identifiable additional pathology or to act appropriately upon identification can impact upon patient welfare and may constitute grounds for medical negligence claims. There is now a tendency to reduce the use of CT in surveillance and this may be proven safe in the future. However, it is likely that the majority of patients will undergo CT at least once before and once after the EVAR, for considerable time to come. Because of the exceptionally good cross-sectional imaging capability, CT in aneurysm patients appears to serve as an ‘unintended screening test’ for additional pathology.
The research team added that there appear to be grounds to debate if the aneurysm patients should be informed that there is a possibility of detection of additional pathology, although this possibility should not be seen as a potentially additional advantage of EVAR.