CHARACTERISTICS OF ETHYLENE-VINYL ALCOHOL COPOLYMER (EVAL) MIXTURES

PURPOSE: To determine physical characteristics of mixtures of ethylene vinyl alcohol copolymer (EVAL) and metrizamide dissolved in dimethyl sulfoxide, liquid materials developed for embolization of arteriovenou s malformations. METHODS: EVAL and dimethyl sulfoxide were mixed in va rious proportions and sterilized. The viscosity and density of each mi xture was measured. Precipitation times were determined by dropping th e mixtures into saline or human blood. The mixtures were filtered and the filtrates weighed. RESULTS: Densities and viscosities of the vario us mixtures differed significantly, proportionally to the concentratio n of EVAL. Precipitation times also differed significantly, in inverse proportion to the concentration of EVAL. Temperature and aqueous solu tion did not affect precipitation times significantly. The weight of t he filtrate significantly increased with time but was constant for eac h precipitation time. Temperature significantly affected filtrate weig ht; aqueous solution did not. CONCLUSIONS: Because of their different physical properties, the various EVAL mixtures are suited to embolizin g different types of arteriovenous malformations.