CD4 and cardiovascular disorder: Of note in patients undergoing cardiac surgery, the fraction of this T cell subset has already been extended during longstanding cardiovascular disease (e.g. long-term hypertension, coronary vessel disease, myocardial infarction or cardiac valve disease) in stable conditions at baseline prior to the surgical intervention – the mechanic stimulus of the surgery per se seems to act as a trigger for CD4+CD28null mediated inflammatory activation.