Management of concealed type iv endoleak and aortic sac hygroma by Prone ContrASt EnHancement Computed Tomography Angiography (PASHA).

Sultan, Sherif; Acharya, Yogesh; Atteia, Emad; Hynes, Niamh

BACKGROUND Aortic sac hygroma (AH) and concealed endoleaks (EL) following endovascular aneurysm repair (EVAR) of abdominal aortic aneurysm (AAA) needs particular attention with aggressive management as they are associated with rapid sac expansion and rupture risk. However, they can be erroneously reported as type IV or V EL with supine computed tomography (CT) scans, leading to delay in management. Therefore, we describe a novel diagnostic technique, 'Prone contrASt enHanced computed tomography Angiography' (PASHA), to document concealed EL. TECHNICAL SUMMARY We present eight case-descriptions with continuous sac expansion following primary EVAR. Management began with diagnosis using the PASHA imaging technique. PASHA is a multi-phase CTA positional technique for increasing the accuracy of detecting EL post-EVAR. The PASHA technique diagnosed all cases of type IIIb EL, as it enhanced the degree of contrast infiltration into the aortic sac when micro-leaks were present. Furthermore, the PASHA imaging technique helped to guide whether the open or endovascular intervention could be employed effectively to manage the sac expansion. In synchrony with the PASHA technique, 'EVAR GORE SalvAge FAbric Technique' (ARAFAT) was used in five elderly patients to salvage previous EVAR. Another three had an open conversion; two with double breasting of the aortic sac and one EVAR explantation. DISCUSSION The PASHA protocol helped classify and localise the concealed ELs (type IV, V), which were not appropriately diagnosed by supine CT protocols. PASHA and ARAFAT were employed as a fully functioning protocol to overcome apparent challenges in accurate diagnosis and subsequent concealed EL management in high-risk patients.