Although contrast-induced nephropathy (CIN) is usually self-limited, it may cause permanent renal injury and even lead to long-term dialysis in patients with preexisting renal impairment. Cardiologists face a dilemma as to whether to alleviate coronary syndromes by coronary intervention or to risk CIN in these patients. Strategies to prevent CIN, including hydration, use of low-osmolal or iso-osmolal contrast media, administration of N-acetylcysteine, and blood purification procedures, were proposed to be effective; however, there are conflicting results. Recently, we found that prophylactic hemodialysis could significantly improve renal survival in patients with advanced renal insufficiency undergoing coronary angiography in a randomized controlled trial. In these patients, fluid supplementation is poorly tolerated and impractical, especially in those with poor heart function. However, the routine use of prophylactic hemodialysis in patients with mild renal insufficiency requires further investigation.