To investigate the correlations between the three-dimensional (3D) parameters of target coronary artery segments and restenosis after stent implantation. Sixty-four patients after single, cobalt chromium platform stent (27 BM stents and 37 DES) implantation were investigated retrospectively 12 ± 6 months after the index procedure. 3D coronary artery reconstruction was performed before and after the stent implantation using appropriate projections by a dedicated reconstruction software. The curve of the target segment was characterized by the ratio of the vessel length measured at midline (arc: A) and the distance between the edge points of the stent (chord: C): A/C ratio (ACr). Age, diabetes and hyperlipidaemia were taken into account for the statistical evaluation. 22 patients were diagnosed with ISR, while 42 patients without any restenosis served as controls. The two groups did not differ regarding major cardiovascular risk factors, proportion of the treated vessels or the type of stents. Higher initial ACr values were associated with greater straightening of the vessel curvature in all groups (p < 0.001). Significant negative correlations were found in cases of proximal or distal edge bending angles (p < 0.001). Pre-stent edge bending angles < 7° often showed an increase after the stent implantation, while in case of higher initial values, the bending angles generally decreased. Using multivariate logistic regression modelling we found that the pre-stent ACr was an independent predictor of in-stent restenosis (odds ratio for 1% increase of the ACr: 1.08; p = 0.012). Changes of angles at the stent edges following stent implantation correlate with the initial local bending angles. The ACr predispose to chronic shear stress in the vessel wall, which may contribute to the pathological intimal proliferation.
Keywords: 3D reconstruction; Arc-chord ratio; Bending angles; In-stent restenosis.