- Guangdong Provincial Cardiovascular Institute (China) All patients with baseline creatinine clearance between 15 to 60 mL/min who undergo cardiac catheterization either electively or following acute coronary syndromes will be approached to participate in this study. After the written informed consent is signed, the patient will be screened for eligibility criteira. Only the eligible patients will be randomly assigned to one of three groups in 1:1:1 ratio.