Background Renal function usually evaluated by detecting the serum creatinine level is an significant prognostic factor in patients with coronary heart disease,however,a normal range of serum creatinine can mask the established renal insufficiency.Therefore,patients with normal serum creatinine level and reduced estimated glomerular filtration rate (eGFR) are likely to be ignored before coronary revascularization;similarly,the prognosis of these groups is easily neglected and still indeterminate.