SIRT1 and intermediate coronary syndrome: Preinfarction angina pectoris can be used as the surrogate marker of ischemicpreconditioning in daily practice and is associated with reduced peak troponinlevels in AMI patients.39 Althoughthe number of subjects were low to make a firm conclusion, no difference was evidentabout serum sirtuin 1, 3 and 6 levels in the patients with and without preinfarction angina.