title: Polyvinyl alcohol particle size for uterine artery embolization: a prospective randomized study of initial use of 350-500 μm particles versus initial use of 500-700 μm particles.
abstract: OBJECTIVE
  To evaluate whether different polyvinyl alcohol (PVA) particle sizes change the outcome of uterine artery embolization (UAE).
  
  
  METHODS
  This randomized prospective study comprised 160 patients with symptomatic leiomyomas undergoing UAE with PVA particles from January to August 2008. In 80 patients in group A, UAE was started with 350-500 μm particles; in 80 patients in group B, UAE was started with 500-700 μm particles. UAE was finished with larger particles when necessary (500-700 μm and 700-900 μm for group A; 700-900 μm for group B). Visual analogue scales were used to measure pain during and in the 4-8 hours after embolization. The outcome of UAE was evaluated at 6 months by pelvic magnetic resonance (MR) imaging, clinical observation, and response to questionnaires.
  
  
  RESULTS
  In group A, PVA particle sizes were as follows: 350-500 μm in 45 patients; 350-500 μm and 500-700 μm in 24 patients; and 350-500 μm, 500-700 μm, and 700-900 μm in 11 patients. In group B, PVA particle sizes were as follows: 500-700 μm in 66 patients and 500-700 μm and 700-900 μm in 14 patients. Mean pain scores during embolization were 1.44 (group A) and 0.97 (group B); after embolization, mean pain scores were 4.71 (group A) and 3.42 (group B) (P < .0001). At 6 months, there were no statistically significant differences in decrease in size of uterus and dominant leiomyoma, in dominant leiomyoma ischemia (P = .31; P = .32), or in the clinical outcome between the two groups.
  
  
  CONCLUSIONS
  The initial use of PVA particle sizes 350-500 μm was associated with a higher mean pain score during and after UAE, although the outcome at 6 months was similar compared with the initial use of particle sizes 500-700 μm.
authors.affiliation: Department of Radiology, St. Louis Hospital, Rua Luz Soriano, no. 182, 1200-249, Faculty of Medical Sciences, New University of Lisbon (Faculdade de Ciências Médicas, Universidade Nova de Lisboa), Lisbon, Portugal. tiagobilhim@hotmail.com
authors.forename: Tiago
authors.initials: T
authors.lastname: Bilhim
authors.forename: João M
authors.initials: JM
authors.lastname: Pisco
authors.forename: Marisa
authors.initials: M
authors.lastname: Duarte
authors.forename: Antonio G
authors.initials: AG
authors.lastname: Oliveira
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007889:Leiomyoma / Q000098:blood supply / Q000628:therapy*; D008279:Magnetic Resonance Imaging; D008863:Microspheres; D008875:Middle Aged; D010146:Pain / Q000209:etiology; D010147:Pain Measurement; D010316:Particle Size; D011142:Polyvinyl Alcohol / Q000008:administration & dosage*; D011174:Portugal; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D013997:Time Factors; D016896:Treatment Outcome; D055357:Uterine Artery Embolization / Q000009:adverse effects; D014594:Uterine Neoplasms / Q000098:blood supply / Q000628:therapy*; D055815:Young Adult
chemical_list: D011142:Polyvinyl Alcohol