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

Abstract

Background: IV hydration before and after cardiac catheterization is effective in preventing contrast-associated renal dysfunction for patients with mild-to-moderate renal insufficiency, but necessitates overnight hospital admission. We tested an outpatient oral precatheterization hydration strategy in comparison with overnight IV hydration.

Methods: We randomized 36 patients with renal dysfunction (serum creatinine > or = 1.4 mg/dL) undergoing elective cardiac catheterization to receive either overnight IV hydration (0.45 normal saline solution at 75 mL/h for both 12 h precatheterization and postcatheterization; n = 18) or an outpatient hydration protocol including precatheterization oral hydration (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 exposure. The predefined primary end point was the maximal change in creatinine 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 group 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 were no instances of protocol intolerance.

Conclusions: A hydration strategy compatible with outpatient cardiac catheterization is comparable to precatheterization and postcatheterization IV hydration in preventing contrast-associated changes in serum creatinine. Hospital admission for IV hydration is unnecessary before elective cardiac catheterization in the setting of mild-to-moderate renal dysfunction.