Background To explore the magnitude and distribution of late lumen loss after biodegradable polymer-based sirolimus-eluting stent implantation.Methods Form March 2010 to December 2010, 300 consecutive patients were included as they implanted only BP stent or PP stent for all diseased vessels.Quantitative analysis was performed on both the "in-stent" and "in-segrnent"area (including the stented segnent, as well as both 5-mm margins proximal and distal to the stent).Late lumen loss was defined as the minimal lumen diameter at the previous angiography minus the MLD at the following angiography.