The aim of the study was to evaluate the behaviour of Type II Endoleaks utilising CEUS, determine the endoleak origin and communication with branch vessels, categorise the endoleak behaviour based on physical characteristics to aid in the interventional decision making process.
This prospective study enrolled 107 patients who had undergone EVAR as treatment for their AAA. All patients underwent routine surveillance utilising CDUS and CEUS to assess for presence/absence of an endoleak. Contrast enhancement within the residual aneurysmal sac indicated the presence of an endoleak. Endoleaks were classified by type, origin and size. Type II endoleaks were subcategorised according to vessel behaviour, origin, communications and duplex Doppler characteristics. CDUS was utilised as a second source of reference and spectral Doppler was utilised to identify blood flow characteristics. CEUS was utilised to enhance the spectral Doppler signal which enabled identification of low flow endoleaks and vessel origins.
Utilising CEUS for increased sensitivity, Type II endoleaks were identified and subcategorised based on vessel origin, behaviour, channel connection and spectral Doppler characterisation. Utilising this Doppler information we enhanced Type II subcategories A and B and devised two further Type II subcategories, Type II C and D. We then questioned the flow dynamic mechanisms for each subcategory. The haemodynamic effect of endoleak subtypes were identified and characterised based on physical principles. Physics of flow dynamics aided our understanding of the various phenomena in the development of Type II endoleak subcategories.
CEUS dramatically enhances the visualisation of endoleak characteristics. Results suggest that Type II C subcategory endoleaks cause an increase in sac size due to the high impedance of flow within the vessel tree. Our study suggests that Type II C endoleaks cause significant risk of rupture due to continued pressurisation of the residual aneurysmal sac and are an indication for secondary intervention.
Rayshelle Finch, Cardiovascular/General Sonographer, PRP Diagnostic Imaging