title: Backup support of the mother-child technique: technical considerations for the size of the mother guiding catheter.
abstract: BACKGROUND
  We previously proposed a technique called the "mother-child technique" to facilitate stent delivery for complex coronary lesions. This technique is applicable when the backup support of the guiding catheter is insufficient. In this study, we used an in vitro coronary artery tree model to determine the impact of the size of the mother guiding catheter on the backup support of the mother-child guiding system.
  
  
  METHODS
  The backup support was measured for the 4-in-5, 4-in-6, 4-in-7, and 4-in-8 systems as well as for the 5-in-6, 5-in-7, and 5-in-8 systems.
  
  
  RESULTS
  Advancement of the child catheter into the coronary artery tree model improved the backup support of the mother-child system. When a 4-Fr child catheter was advanced by 9 cm, the relative increase in the backup support was 174% in the 4-in-5 system; it was 203% in the 4-in-6, and 135% in the 4-in-7 system (P < 0.05 vs. the mother catheter alone). The relative increase with the 5-Fr child catheter was 289% in the 5-in-6 system, and 152% in the 5-in-7 system (P < 0.0001 vs. the mother catheter alone). However, the improvement in the backup support with 9-cm child catheter advancement did not reach statistical significance for either the 4-in-8 (115%) or the 5-in-8 (112%) system (P = NS).
  
  
  CONCLUSIONS
  The relative increase in the backup support of the mother-child system was inversely related to the size of the mother guiding catheter. Thus, the mother-child technique may be most useful for PCIs in which a small guiding catheter is used, such as transradial coronary interventions.
authors.affiliation: Department of Cardiology and Catheterization Laboratory, Shonan Kamakura General Hospital, Kamakura, Kanagawa, Japan. stake@muse.ocn.ne.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Takeshita
authors.forename: Ayumu
authors.initials: A
authors.lastname: Takagi
authors.forename: Shigeru
authors.initials: S
authors.lastname: Saito
mesh_terms: D006328:Cardiac Catheterization / Q000295:instrumentation* / Q000379:methods*; D062906:Cardiac Catheters; D003331:Coronary Vessels / Q000033:anatomy & histology*; D004867:Equipment Design; D006801:Humans; D008953:Models, Anatomic; D062645:Percutaneous Coronary Intervention / Q000295:instrumentation* / Q000379:methods*; D011474:Prosthesis Design; D015607:Stents