Proper hydration enhances contrast-induced nephropathy prevention

Pre-imaging intravenous hydration with sodium chloride remains the best prophylactic approach against contrast-induced nephropathy in patients with impaired renal function who must undergo coronary angiography, according to results from a large multicenter trial.

Contrast-induced nephropathy leads to considerable complications, prolonged hospital stays, and nearly $200 million a year in healthcare costs. Avoidance of nephrotoxic drugs and adequate periprocedural IV hydration with sodium chloride remain the most widely used strategies for prevention of CIN.

Recent studies have explored the use of sodium bicarbonate as an alternative hydration technique. The first large-scale, long-term randomized trial of contrast nephropathy performed by researchers from four medical institutions in New York and California showed that it is reasonable to use either fluid type.

Study findings suggest, however, that using sodium bicarbonate offers no clinically meaningful advantage, said principal investigator Dr. Somjot S. Brar, an interventional cardiologist at Columbia University Medical Center.

"Sodium bicarbonate is generally not available and requires additional resource utilization to mix the solution," Brar told Diagnostic Imaging. "Also, sodium bicarbonate is not compatible with some intravenous medications and therefore requires additional intravenous access."

Brar and colleagues prospectively enrolled 353 patients aged 18 or older with stable renal disease scheduled to undergo coronary angiography from January 2006 to January 2007. Patients were randomized to receive either sodium chloride (n = 178) or sodium bicarbonate (n = 175) administered at the same rate. The investigators found no statistically significant difference between the two fluids for the prevention of CIN.

They published findings in the Journal of the American Medical Association (2008;300[9]:1038-1046).

Patients averaged 71 years, and nearly half had diabetes mellitus. Their rates of death, dialysis, myocardial infarction, transient ischemic attack, and stroke did not differ significantly at either 30-day or six-month follow-up (p>0.1). The risk of CIN in patients with moderate to severe kidney disease undergoing either hydration protocol was 13% to 14%. About one in five of those developing the condition sustained persistent renal impairment, and fewer than 2% required dialysis by six months.

Study results can reassure physicians and patients that sodium chloride and sodium bicarbonate are comparable for periprocedural hydration, but they need to keep in mind the latter's shortcomings, Brar said.

"These inconveniences, given the apparent lack of benefit over sodium chloride infusion, will likely not justify its use in most settings," Brar said.

For more information from the Diagnostic Imaging archives:

Study sheds light on contrast-induced nephropathy in high-risk patientsContrast-induced nephropathy fears easeOral fluids may dilute contrast reaction risk in patients with kidney disordersCheap drug protects against CT contrast-induced nephropathy