A non-occlusive blood-restricting device is provided for use with a microcatheter and for treating a vascular malformation. The device includes a first section, a second section, and an intermediate section. The first section is configured to assume a first shape when deployed from the microcatheter within a portion of the vascular malformation so as to at least partially cover an orifice of the vascular malformation. The first shape defines a sequence of loops having a gradually decreasing diameter. The second section is configured to assume a second shape when deployed from the microcatheter, wherein the second shape defines a sequence of one or more loops having a constant or gradually decreasing diameter. The intermediate section connects the first and the second sections and is configured to space apart the first and the second sections when deployed from the microcatheter. Other embodiments are also described.