Oral versus Intravenous Hydration to Prevent Contrast Induced Nephropathy

Contrast media are frequently used in diagnostic and therapeutic procedures.
Although replacement of high osmolar iodinated contrast media by low osmolar
non-ionic contrast media has reduced the number of adverse events, acute renal
failure is still a regular and severe complication seen after intravascular
administration of iodinated contrast media.

This contrast-induced nephropathy (CIN), defined as a rise of serum creatinine
>= 25% or >=44 umol/L within 48 to 72 hours after administration of contrast
media, is associated with marked morbidity and mortality.
In 2007, CBO guidelines for the prevention of CIN have been developed.
(CIN is also one of the targets of the Dutch Ministry of health/VMS safety
program.)
All patients are screened for risk factors, which includes measurement of renal
function by estimating glomerular filtration rate (eGFR) using the MDRD formula.
High risk patients are admitted to the hospital for treatment with intravenous
saline for a period of 8-24 hours. Between 48-72 hours after the procedure
their renal function is checked.
This approach has a large impact on health care resources.
The total number of procedures with contrast media amounts approximately 1
million/year in the Netherlands and is expected to increase in the nearby
future.
Following the guideline approximately 10% of patients will be admitted for
in-hospital intravenous hydration. The total number of hospital days needed for
this strategy amounts approximately 180.000/year.

This proposal evaluates an alternative procedure for the prevention of CIN.
The alternative procedure involves home-hydration with salt tablets, under
supervised care with monitoring of diuresis and body-weight , and should reduce
the need for hospitalisation of the patients.

In two small RCT*s it was shown that home hydration may be as effective as
intravenous hydration. The largest study involved 76 patients per arm, and
observed an incidence of CIN of 5.2% after hospital hydration and 6.6% after
home hydration using oral administration of salt capsules. Due to low numbers
of patients a difference of 10% between the groups cannot be excluded.

We expect that effective home hydration will almost completely eliminate the
need for hospitalisation for elective procedures. The new procedure will save
costs, but also limit the use of scarce hospital capacity. In addition, it is
hypothesized that patient satisfaction and quality of life increases in the
home hydration setting.

To investigate if home-hydration is a non inferior alternative for
in-hospital hydration in the prevention of Contrast Induced Nephropathy in high
risk patients.

multi-centre randomized controlled trial

Arm A: sodium chloride 1g/10kg of body weight /day per os on day -2 and -1
before contrast exposure. (maximum of 10 gram per day in case of obesitas)
Arm B (standard procedure): Nacl 0.9% total 1000ml in 4 hrs or (in case of
heart failure or severe renal failure) 12 hrs before and in 4 or in 12 hrs
after contrast administration.

Patients who are randomized for home hydration will receive salt tablets and
start 48 hrs before the procedure. The risk of taking salt tablets is low,
there are some reports of nausea. Because we exclude patients who have
decompensated heart failure the use of these amounts of salt is considered safe
and we do not expect signs of overhydration. We monitor this by a telephone
consult, 24 hours after the intake of the first tablets. Body weight and intake
of tablets will be monitored. Before contrast administration a blood and urine
sample will be taken.
Patients who are randomized for intravenous hydration will be admitted and will
receive standard treatment for high risk patients with the addition of one
blood and urine sample taken before contrast administration.These patients
will also be asked to participate in our study *Risk prediction of
Contrast-Induced Nephropathy* 31607 (ARB)
In all patients 48-72 hours after contrast administration a blood sample is
taken to check for the development of CIN, this is standard treatment according
to the guidelines.
We will ask all patients to fill in a questionnaire on patient satisfaction.