the vessel
patent (open to flow). The design considerations are multiple. Not only must be biocompatible,
the latticework must be capable of radial expansion and yet not break, collapse,
or deform. The device must be ductile enough to expand. Fibrin deposits, blood
flow patterns, and clot formation are causes of device failures, and much research
focuses on refining designs that are robust and resistant to occlusion. Also, it may be
difficult or impossible to retrieve a device once it is deployed into the body, so the
design engineer must conduct extensive testing, modeling, and validation prior to
release of the device