PREPARED: PREParation for Angiography in REnal Dysfunction - A randomized trial of inpatient vs outpatient hydration protocols for cardiac catheterization in mild-to-moderate renal dysfunction

Background: IV hydration before and after cardiac catheterization is effect ive in preventing contrast-associated renal dysfunction for patients with m ild-to-moderate renal insufficiency, but necessitates overnight hospital ad mission. We tested an outpatient oral precatheterization hydration strategy in comparison with overnight IV hydration, Methods: We randomized 36 patients with renal dysfunction (serum creatinine greater than or equal to 1.4 mg/dL) undergoing elective cardiac catheteriz ation to receive either overnight IV hydration (0.45 normal saline solution at 75 mL/h for both 12 h precatheterization and postcatheterization; n = 1 8) or an outpatient hydration protocol including precatheterization oral hy dration (1,000 mL clear liquid over 10 h) followed by 6 h of IV hydration ( 0.45 normal saline solution at 300 mL/h) beginning just before contrast exp osure. The predefined primary end point was the maximal change in creatinin e up to 48 h after cardiac catheterization. Results: The inpatient and outpatient groups were well matched for baseline characteristics and contrast volume, By protocol design, the outpatient gr oup received a greater volume of hydration, although the net volume changes were comparable in the two groups. The maximal changes in serum creatinine in the inpatient (0.21 +/- 0.38 mg/dL; 95% confidence interval [CI], 0.02 to 0.39 mg/dL) and outpatient groups (0.12 +/- 0.23 mg/dL; 95% CI, 0.01 to 0.24 mg/dL) were comparable (p = not significant). There n ere no instances of protocol intolerance, Conclusions: A hydration strategy compatible with outpatient cardiac cathet erization is comparable to precatheterization and postcatheterization IV hy dration in preventing contrast-associated changes in serum creatinine, Hosp ital admission for IV hydration is unnecessary before elective cardiac cath eterization in the setting of mild-to-moderate renal dysfunction.