Modified kissing balloon inflation associated with better results after Culotte stenting for bifurcation lesions: A bench test

Background: Main vessel (MV) stent deformation and overstretch caused by classical kissing balloon inflation (C-KBI) using two balloons with a longer overlapping in the MV for bifurcation lesions has caused a widespread concern.

Purpose: This bench study tested our hypothesis that mini-KBI (M-KBI) with a shorter protrusion of side branch (SB) balloon would ascertain a better result after Culotte stenting.

Methods: Twenty-four coronary stents were deployed using Culotte approach in twelve bifurcation models with a bifurcation angle of 45°, 3.5 mm in MV diameter, and 3.0 mm in SB diameter. After stent implantation, the final KBI were assigned to C-KBI (two kissing balloons juxtaposed within the MV stent, at least overlap for 3 mm; n = 6) and M-KBI (the proximal marker of SB balloon just sited at the level of upper edge of SB ostium; n = 6). Proximal optimization technique (POT) was performed after KBI. Stent geometry was visually evaluated based on bench photos, microscopy, videoscopy, micro-CT, and scanning electron microscopy. Stent deformation index, minimal lumen diameter, and cross-sectional area at either carina level of MV and ostium of SB were measured from optical coherence tomography (OCT).

Results: In Culotte technique, C-KBI was associated with visually significant stent deformation, overexpansion and the "bottleneck" effect of the MV stent, which could not be effectively rectified by POT, while M-KBI could keep the circle shape of MV stent with good stent apposition in both MV and SB stent. By quantitative measurements, deformation index of MV was 0.06 ± 0.01 after M-KBI, significantly lower than 0.25 ± 0.02 if C-KBI was performed. In the line in carina, compared to C-KBI, M-KBI has smaller CSA-stent/CSA-reference, which indicated a less overstretch of MV stent. However, minimal lumen diameter and cross-sectional area of SB ostium was not different in the mini-KBI group (3.0958 ± 0.0285 mm and 7.9667 ± 0.1741 mm), when compared those after C-KBI (3.1217 ± 0.0772 mm and 7.9083 ± 0.3115 mm, p > .05).

Conclusions: Followed by POT, M-KBI is preferable than C-KBI in preventing stent deformation, overexpansion in MV stent and could get well apposed of MV stent and well-opened SB stent as expected in a Culotte technique.