title: Stretched minimal diameter of the ductus and coil occlusion.
abstract: BACKGROUND
  Stretching of the ductus was supposed to determine the size mismatch of the coil with the ductus in coil occlusion that results in residual leak or migration.
  
  
  METHODS
  We measured the minimal diameter (D) and the stretched minimal diameter (S) of the ductus in 12 patients with patent ductus arteriosus (PDA). The stretch index (SI) was calculated as S divided by D. We calculated ratios of the loop diameter of the first implanted coil to D (C1/D) and S (C1/S) and those of the sum of all the loop diameters of all implanted coils for complete closure to D (total C/D) and to S (total C/S).
  
  
  RESULTS
  Stretched minimal diameter divided by D was 1.8 +/- 0.3. Ratios of the loop diameter of the first implanted coil to D (C1/D), and S (C1/S) were 3.7 +/- 1.8 and 2.1 +/- 0.9, respectively. Ratios of the sum of all the loop diameters of all coils to D (total C/D) and S (total C/S) were 5.2 +/- 1.6 and 2.9 +/- 0.9, respectively. Standard deviations of C1/S and total C/S are significantly smaller than those of C1/D and total C/D, respectively.
  
  
  CONCLUSIONS
  The narrowest segment of the ductus could be stretched to twice the size of the minimal diameter. The stretched minimal diameter may be a more reliable parameter to select the loop diameter of coils than the angiographic minimal diameter.
authors.affiliation: Department of Pediatrics, Sapporo Medical University, School of Medicine, Japan. tomitah@sapmed.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Tomita
authors.forename: S
authors.initials: S
authors.lastname: Fuse
authors.forename: S
authors.initials: S
authors.lastname: Chiba
mesh_terms: D002404:Catheterization; D002675:Child, Preschool; D004373:Ductus Arteriosus / Q000000981:diagnostic imaging / Q000473:pathology*; D004374:Ductus Arteriosus, Patent / Q000601:surgery*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D019736:Prostheses and Implants; D011859:Radiography