Backup support of the mother-child technique: Technical considerations for the size of the mother guiding catheter

Background: We previously proposed a technique called the motherchild 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 motherchild 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 motherchild 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 motherchild system was inversely related to the size of the mother guiding catheter. Thus, the motherchild technique may be most useful for PCIs in which a small guiding catheter is used, such as transradial coronary interventions. (C) 2012 Wiley Periodicals, Inc.