[Contrast-induced acute renal failure].

: The administration of radiocontrast media (RC) can lead to usually a reversible form of acute renal failure (ARF) that begins soon after the contrast is administered. A functional definition of RC-induced ARF varies among different studies: most commonly reported as a proportional rise in serum creatinine (Cr), 25 or 50% above baseline or an absolute rise of 0.5-1.0 mg/dL within 48 hr after exposure to RC. Serum Cr returns to baseline over 8-12 days. Sometimes ARF is irreversible, contributing to an increase in mortality. Iodinated RC are either ionic or non-ionic and, at the concentrations required for arteriography or computed tomography, are of variable osmolality. Considering the main ARF risk factors, a rise in plasma Cr is: negligible with normal renal function, even if the patient is diabetic; 4-11% with mild to moderate renal insufficiency alone (plasma Cr between 1.5 and 4.0 mg/dL); 9-38% with mild to moderate renal insufficiency and diabetes mellitus; > or =50% if baseline plasma Cr is >4-5 mg/dL, particularly in patients with diabetic nephropathy. This risk, however, is increased further by more advanced renal dysfunction, marked volume depletion, severe heart failure, or multiple contrast studies within 72-hr. Pathogenesis is not well understood, but the mechanism by which nephrotoxins induce renal injury is generally by either vascular or direct tubular effects. In the case of RC ARF, there appears to be an influence of both mechanisms, although altered renal hemodynamics predominates. Both are thought to occur from exposure to the hyperosmolar agent. The best treatment for contrast-induced renal failure is prevention. Some preventive measures include the use, if clinically possible, of ultrasonography, magnetic resonance imaging or CT scanning without RC agents, particularly, in high-risk patients; the use of lower contrast doses and the avoidance of frequent repetitive studies; the avoidance of volume depletion or non-steroidal anti-inflammatory drugs; the administration of intravenous saline and the antioxidant acetylcysteine; the use of low or iso-osmolal non-ionic contrast agents, particularly in high risk patients.