Description of the Concept of Vessel Size (RVD), Vessel Sizing (Relationship Between Nominal Device Diameter and RVD)
The bottom left panel shows scaffold restenosis (ScR) as a function of bioresorbable coronary scaffold (BRS) sizing (nominal diameter/reference vessel diameter [RVD]). (Top panels) Undersizing (choice of a BRS >9% smaller than the RVD, or nominal diameter/RVD <0.91) and oversizing (nominal diameter/RVD >1.13) were both associated with increased risk of ScR. Oversizing might lead to vessel trauma and increased strut density, which both stimulate proliferation. Undersizing might lead to malapposition and disruption in the laminarity of the flow, also a stimulus for neointima growth. The bottom right panel shows the incidence of ScR was also significantly higher for vessels with RVD <2.7 mm. Importantly, the incidence further increased for smaller RVD, showing a gradient in the risk of ScR with decreasing RVD. KM = Kaplan-Meier.