Contrast Arterial Transit Time on Final DSA Predicts Persistent Type II Endoleak after EVAR: A Pilot Study
Abstract
Purpose
The goal of this study was to investigate whether measuring arterial transit time (AT) using the last digital subtraction angiography (DSA) in patients with persistent type II endoleaks (T2E) after repair of an abdominal aortic aneurysm (EVAR) could be a means for early detection of persistent T2E or non-persistent T2E.
Methods
This study involved the retrospective analysis of sixteen patients who had undergone EVAR: eight with persistent T2E at one year post procedure, and eight without endoleaks. AT was defined as the duration of time from when contrast material first entered the lowest renal artery until it first reached the highest iliac artery during the final DSA examination, using frame rates taken from DICOM metadata. The median AT was compared between both groups using the Mann-Whitney U test, and a p-value of less than 0.05 indicated statistical significance.
Results
Median AT was significantly shorter in the persistent T2E group (6.08 s; interquartile range 5.85-6.25) compared with the no-endoleak group (7.75 s; interquartile range 6.94-8.75; p = 0.0013). This finding indicates that patients with persistent T2E had a faster rate of contrast passage through their arteries with respect to the no-endoleak group. This supports previous findings that persistent T2E is associated with greater amounts of collateral flow due to lower-resistance channels. Measuring the AT at the iliac artery can be a useful indicator of the global hemodynamics of the aorto-iliac region, even when direct measurement of the endoleak sac is not possible.
Conclusion
Final DSA arterial transit time is a potential biomarker for sustained T2E (type II endoleak). This new imaging method can help with post-EVAR risk assessment and patients risk stratification. Ongoing studies will look into AI-assisted endoleak cavity segmentation and the auto-analysis of endoleak cavities to improve predictive power and apply findings in clinical practice.