Recently, Nedergaad et al. suggested the “glymphatic pathway,” consisting of para-arterial CSF influx route, para-venous ISF efflux route, and convective bulk fluid flux (Iliff and Nedergaard, 2013; Nedergaard, 2013), as another clearance system in central nervous system. Aβ proteins may be cleared through this perivascular pathway, as well as the perivascular drainage system (Iliff et al., 2012), although the relationship to CAA pathogenesis remains to be clarified as Aβ does not accumulate in the venous system. Cerebral arterial pulsation with a vasoactive agent dobutamine drives perivascular CSF–ISF exchange (Iliff et al., 2013). Further investigation is required to determine whether other vasoactive drugs such as cilostazol could have a potential to facilitate paravascular clearance.
