Effects of Number of Stent Connectors on Mid-Term Vessel Healing and Stent Expansion Assessed by Optical Coherence Tomography

Abstract

Objective: Coronary stents generally consist of hoops and connectors. The number of connectors has been associated with longitudinal strength, flexibility, and deliverability of stents. However, a mid-term impact of number of connectors after stent implantation has been unclear. We sought to examine the effect of number of connectors on vessel healing and stent expansion using optical coherence tomography (OCT). Materials and Methods:The study included 39 patients with 46 Promus PREMIER stents who underwent OCT examination at 8 months after stent deployment. Promus PREMIER stents have 4 or 5 connectors in a proximal few-millimeter segment of the stents and 2 connectors in the entire stents except the proximal few millimeters. We analyzed OCT cross-sectional images in the proximal 4-or 5-connector segments and adjacent 2-connector segments at 1-mm intervals. OCT parameters including stent apposition, neointimal coverage, the presence of peri-strut low-intensity area (PLIA), stent area, maximal and minimum stent diameters, and stent eccentricity index were compared between the 2 segments. Results: The 4-or 5-connector segments had a significantly higher proportion of well-apposed struts without neointima (5.8% [interquartile range (IQR): 0-21.9%]) compared to the 2-connector segments (0% [IQR: 0-91.3%], p = 0.007). The proportion of struts with PLIA was higher in the 4-or 5-connector segments (7.1% [IQR: 0-32.0%]) than in the 2-connector segments (0% [IQR: 0-14.6%], p = 0.026). Stent area, maximal and minimum stent diameters, and stent eccentricity index were comparable between the 2 segments. Conclusion:The number of connectors were associated with vessel healing processes including neointimal coverage and the presence of PLIA but did not restrict stent expansion.