A non-occlusive blood-restricting device is provided for treating a vascular malformation. The blood-restricting device includes a first section configured to assume a first shape when deployed from a microcatheter within a portion of the vascular malformation so as to at least partially cover an orifice of the vascular malformation, the portion of the vascular malformation including one or more anatomical features selected from the group consisting of: a neck of the vascular malformation and a wall of the vascular malformation. The first shape defines a sequence of loops having a gradually decreasing diameter and coaxial around a first central axis. The blood-restricting device also includes a second section configured to assume a second shape when deployed from the microcatheter. The second shape defines a single loop around a second central axis when the blood-restricting device is not restrained. Other embodiments are also described.
