Intravascular ultrasound comparison of the self‐expanding sideguard stent in the side branch versus a balloon‐expandable stent in the main vessel to assess mechanisms of acute lumen gain in bifurcation lesions

Abstract

We compared the mechanisms of lumen gain after Cappella Sideguard (CS) side branch (SB) bifurcation stent deployment versus a balloon-expandable stent in the corresponding main vessel (MV). The novel CS SB bifurcation stent is a self-expanding, thin-strut, nitinol device with anatomic flaring at the SB ostium. In 28 bifurcation lesions, intravascular ultrasound imaging of both the SB and the MV was performed both pre- and postintervention; vessel and lumen areas were measured every 1 mm over a 5 mm segment beginning at the carina. Although minimum lumen area (MLA) within the distal 5 mm segment beginning at the carina increased from 2.8 ± 1.3 mm(2) to 3.8 ± 1.1 mm(2), P < 0.001, in the SB and from 3.4 ± 1.4 mm(2) to 6.0 ± 1.1 mm(2), P < 0.001, in the MV, stent expansion (minimum stent area/distal reference lumen area) was significantly less in the SB compared with the MV (77.8 ± 21.3% vs. 91.6 ± 18.4%, P = 0.02). Post stenting, the MLA site was located at the carina more frequently in the SB (85.7%) than in the MV (60.7%), P = 0.04. Plaque volume in the 5 mm proximal to carina in the MV tended to decrease, whereas plaque volume in the SB increased slightly with no change in overall plaque volume in the 5-mm-long segment distal to the carina in the MV, suggesting plaque shift from the proximal MV to the SB. Acute CS lumen gain is less than the lumen gain of a balloon-expandable stent in the MV because of less aggressive acute expansion and/or the plaque shift from the proximal MV to the SB.