Immunohistochemistry was performed on de-paraffinized aortic tissue sections treated with DIVA solution (Biocare Medical, Concord, CA, USA), as described previously [5 (link)]. The expression of ZEB2 was quantified in n = 10 BAV-ND patients, and n = 11 TAV-ND patients, using mouse monoclonal anti-ZEB2 (Santa Cruz, Heidelberg, Germany, sc-271984). Quantification of per cent area positive staining was performed using Image-Pro® Premier version 9.1 Software (Media Cybernetics®, Silver Spring, MD, USA).