Between Oct 10 , 2010 , and July 17 , 2012 , 396 patients aged 18 years or older undergoing cardiac catheterisation with an estimated glomerular filtration rate of 60 mL/min per 173 m ( 2 ) or less and one or more of several risk factors ( diabetes mellitus , history of congestive heart failure , hypertension , or age older than 75 years ) were randomly allocated in a 1:1 ratio to left ventricular end-diastolic pressure-guided volume expansion ( n = 196 ) or the control group ( n = 200 ) who received a standard fluid administration protocol .