Structural dysregulation of the pulmonary autograft was associated with a greater density of p16INK4A-vascular smooth muscle cells

•The pulmonary autograft of patients that underwent the Ross Procedure was associated with a neointimal region, medial thinning and reduced elastin content•The structural dysregulation of the pulmonary autograft was associated with increased protein levels of matrix metalloproteinase-9 and the cell cycle inhibitor p27kip1•The medial region of the pulmonary autograft was associated with a heightened senescent phenotype charcterized by the greater density of p16INK4A/non-muscle myosin IIB(+) vascular smooth muscle cells•The senescent phenotype of VSMCs may represent the predominant source of increased MMP-9 expression translating to elastin degradation, medial thinning and neointimal formation of the pulmonary autograft