IVUS = intravascular ultrasound; IQR = interquartile range; SD = standard deviation. Note: Numbers in the table are summaries of the patient level means e.g. for each patient the mean wall thickness of all IVUS measurements was calculated; summary statistics of these individual patient level means are presented. *Missing data on 50 vein grafts (High pressure, low pressure, conventional harvest, pedicled harvest): Withdrew from IVUS (14,14,11,17). Occluded (8,4,8,4), IVUS Problems (4,0,0,4), Missing (3,3,1,5).