NEW YORK (Reuters Health) - In patients undergoing cardiac catheterization, intravenous acetylcysteine provides a rapid and effective protocol for the prevention of radiocontrast-induced nephropathy (RCIN) when time constraints preclude adequate prophylaxis the day before with oral saline hydration.

These findings are reported in the June 18th issue of the Journal of the American College of Cardiology by Dr. Christopher S. R. Baker from Hammersmith Hospitals NHS Trust in London and colleagues. RCIN may occur in as many as 14.5% of patients undergoing coronary angiography/intervention, they note, and it is the third most common cause of in-hospital acute renal failure after hypotension and surgery.

Successful prophylactic protocols studied to date require the initiation of therapy on the day before contrast exposure, precluding the treatment of same-day and emergency patients.

In a prospective randomized trial of 80 patients undergoing cardiac catheterization, Dr. Baker's team found that a rapid protocol of IV acetylcysteine (150 mg/kg in 500 mL 0.9% saline) for 30 minutes right before contrast followed by a 4-hour infusion of acetylcysteine (50 mg/kg in 500 mL 0.9% saline) over 4 hours is an effective means of preventing transient RCIN.

RCIN occurred in 2 of 41 (5%) of patients treated with the rapid IV acetylcysteine protocol compared with 8 of 39 (21%) of those treated with IV hydration 12 hours pre- and post-contrast induction.

Moreover, in the IV acetylcysteine group, serum creatinine fell from 1.85 to 1.77 and 1.79 mg/dL at 48 hours and at 4 days after contrast, both significant declines compared with baseline levels.

In the oral hydration group, serum creatinine increased from 1.75 to 1.81 after 48 hours, and to 1.80 mg/dL after 4 days, following contrast administration (p= 0.99 and p=0.23, respectively).

In three patients (7%), IV acetylcysteine was halted after the bolus due to flushing, itching, or a transient rash.

Dr. Baker's team recommends that "administration of IV NAC should be considered in all patients at risk of RCIN before contrast exposure when time constraints preclude adequate oral prophylaxis, provided the patient is able to tolerate this degree of volume loading."

"We are now able to treat patients who can't wait for 12 hours for the acetylcysteine to have its effect," Dr. Baker told Reuters Health. These findings also add "strength to previous reports of a similar degree of protection when oral acetylcysteine is given starting 12-24 hours prior to the contrast exposure."

However, Dr. Baker pointed out that "a number of cautions in particular care need to be taken with the fluid load in patients with left ventricular dysfunction--and occasional anaphylactoid reactions are known to occur."

J Am Coll Cardiol 2003;41:2114-2118.

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