Patients at moderate and high risk for contrast induced nephropathy (CIN) should receive sufficient hydration before application of contrast to prevent CIN, but hydration could obviously increase the preload for congestive heart failure (CHF) patients. It is important to make an individual hydration protocol for patients with dysfunction of heart and renal to reduce the incidence rate of CIN. This prospective, randomized, double-blind, comparative clinical trial randomly selected 264 patients with estimated glomerular filtration rate, (eGFR) <60 ml/min per 1.73 m2 and CHF undergoing coronary angiography to receive either the convention hydration (n=132) or the central venous pressure (CVP) guided hydration (n=132).