Management of Concealed Type IV Endoleak and Aortic Sac Hygroma by Prone ContrASt EnHancement Computed Tomography Angiography.

BACKGROUND: Aortic sac hygroma and concealed endoleaks (EL) after endovascular aneurysm repair (EVAR) of abdominal aortic aneurysm 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 METHODS: We present eight case descriptions with continuous sac expansion after primary EVAR. Management began with diagnosis using the PASHA imaging technique. PASHA is a multiphase CTA positional technique for increasing the accuracy of detecting EL after EVAR. Furthermore, the PASHA imaging technique also guides whether the open or endovascular intervention could be used effectively to manage the sac expansion. In synchrony with the PASHA technique, "EVAR GORE SalvAge FAbric Technique" (ARAFAT) was to salvage previous EVAR.

RESULTS: The PASHA technique diagnosed all cases of type IIIb EL, as it enhanced the degree of contrast infiltration into the aortic sac when microleaks were present. ARAFAT was effectively used in five elderly patients. Another three had an open conversion; two with double breasting of the aortic sac and one EVAR explantation.

CONCLUSIONS: The PASHA protocol helped classify and localize the concealed EL (type IV, V), which were not appropriately diagnosed by supine CT protocols. PASHA and ARAFAT were used as a fully functioning protocol to overcome apparent challenges in accurate diagnosis and subsequent concealed EL management in high-risk patients.