Expansion in calcific lesions and overall clinical outcomes following bioresorbable scaffold implantation optimized with intravascular ultrasound

Objectives: This study aimed to investigate clinical outcomes following bioresorbable scaffold (BRS) optimized with intravascular ultrasound (IVUS), and furthermore expansion of BRS in calcific lesions. Background: Although IVUS use has contributed to improved clinical outcomes with metallic stent implantation, it is unclear if this is also true with regards to BRS, especially in calcified lesions. Methods: Between May 2012 and April 2015, 291 lesions in 198 patients were treated with BRS with IVUS use. We evaluated overall clinical outcomes at 1-year and investigated the expansion and eccentricity index of BRS amongst quadrants categorized by calcium arc (CA) every 90-degrees. Results: The rates of major adverse cardiac events were 5.4% (at 6 months) and 10.7% (at 12 months). TLR was observed in 3.1% at 6-month and 7.5% at 12-month follow up. Although there was a significant difference among quadrants regarding to eccentricity of calcium (0°≦CA < 90°: 0.82 ± 0.09, 90°≦CA < 180°: 0.75 ± 0.12, 180°≦CA < 270°: 0.78 ± 0.11, and 270°≦CA≦360°: 0.79 ± 0.09, ANOVA P = 0.002), the BRS expansion index [minimal scaffold area (MSA) divided by BRS area expanded at a nominal pressure] was comparable between quadrants. Conclusions: The use of IVUS to optimize BRS implantation results in favorable clinical outcomes even for complex lesions. Although eccentric calcium distribution resulted in asymmetric expansion of BRS, the final MSA was comparable irrespective of calcium distribution.