In vitro and human studies of a 4F double-coaxial technique ("mother-child" configuration) to facilitate stent implantation in resistant coronary vessels.

BACKGROUND We recently developed a 4F child catheter that can be inserted into 6F or larger conventional guiding catheters. The use of 4F mother-child technique may improve the delivery of coronary stents to complex lesions. Accordingly, we sought to determine the potential of using a 4F mother-child technique to treat complex coronary lesions. METHODS AND RESULTS The support power and the trackability of the mother-child technique of 4-in-6 were evaluated using a coronary artery tree model. In addition, the results of 51 lesions treated by using a 4F child catheter were retrospectively analyzed. The in vitro experiment demonstrated that backup support of the 4-in-6 system was increased when the child catheter was advanced into the coronary tree ≥5 cm (P≤0.01); further, the 4F child catheter was associated with superior trackability as compared with a 5F child catheter (15.0 cm [15.0 to 15.0] versus 13.0 cm [12.8 to 13.0], P<0.005). A total of 51 lesions, in which conventional techniques had been unsuccessful, were treated using the 4F mother-child technique. Lesion success was achieved in 48 (94%) lesions. Stent deployment was attempted in 44 (86%) and was successful in 40 of 44 (91%). There were 2 instances of stent dislodgment. CONCLUSIONS With the superior trackability of the 4F child catheter and with increased backup support of the mother-child system, the 4F mother-child system provided >90% success rate for lesions in which conventional techniques had failed. The 4F mother-child system may become a viable alternative to conventional techniques in treating complex coronary lesions.