Impact of eccentric and calcified plaque on bioresorbable scaffold and drug-eluting metallic stent expansion characteristics: a comparative intravascular ultrasound study

Previous studies have demonstrated greater lumen eccentricity and asymmetry with BRS compared to DES, but evidence regarding their expansion performance in complex lesions characterized by eccentric morphology or calcification remains scarce. This study aimed to compare and analyze the acute device performance of bioresorbable scaffolds (BRS) versus drug-eluting metallic stents (DES) using intravascular ultrasound (IVUS), and their expansion characteristics in eccentric and calcified lesions. IVUS analysis was performed pre- and post-procedure in 184 patients (48 BRS and 136 DES). Plaque eccentricity was quantified during pre-procedural using the plaque eccentricity index (PEI), with lesions stratified by calcification severity (no/mild: ≤90°; moderate/severe: >90° arc), while post-procedural device expansion performance was evaluated through three IVUS parameters including asymmetry index (AI), expansion ratio (ER) and eccentricity index (SEI). Pre-procedural PEI demonstrated predictive value for post-procedural SEI and AI in both groups, yielding Areas Under the Curve (AUCs) of 0.811 and 0.773 for BRS, and 0.747 and 0.713 for DES. At high PEI, BRS showed significantly lower SEI than DES (0.87 vs. 0.91, P < 0.001). Moderate/severe calcification significantly increased AI in both BRS (0.36 vs. 0.32, P = 0.029) and DES (0.34 vs. 0.31, P = 0.025). Eccentric distribution of plaque affects symmetry and uniformity of device expansion, and device eccentricity was more affected by the degree of pre-procedural plaque eccentricity in BRS than in DES. Moreover, calcified plaque further exacerbated post-procedural device asymmetry.