Commentary: Targeted Renal Therapy: A Potential Weapon in the Battle Against CIN

Contrast-induced nephropathy (CIN) is the third commonest cause of hospital acquired renal injury. The incidence of CIN is increasing with the advent of complex endovascular interventional procedures in conjunction with an aging population with chronic renal impairment. Clearly, strategies aimed at preventing or reducing the risk of CIN are required. The essential aspects of CIN prophylaxis are (1) adequate risk assessment, that is, identification of those patients at high risk of developing CIN; (2) control of modifiable risk factors, such as the withdrawal of nephrotoxic drugs 24 hours prior to contrast administration; and (3) optimal fluid management. Despite extensive investigation, the only intervention that is proven to reduce the risk of CIN prior to coronary intervention is prehydration with isotonic saline, and no therapeutic agent has been demonstrated conclusively to reduce risk. A number of contemporary randomized controlled trials (RCTs) have reported various therapeutic strategies aimed at reducing CIN. In summary, however, although iso-osmolar contrast may have benefits over low-osmolar contrast agents and sodium bicarbonate may be more beneficial than normal saline, the jury is still out. Furthermore, there is little available data on the prevention of CIN during peripheral arterial intervention, so further studies, such as the one reported in this issue by Weisz et al., are required in this patient group. Targeted renal therapy (TRT) with direct delivery of renoprotective agents to the renal arteries during interventional procedures is an exciting advance in the prevention of CIN. It potentially eliminates the first-pass metabolism seen with orally administered agents such as N-acetylcysteine, thus increasing drug bioavailability; in addition, direct renal delivery may reduce the systemic side effects previously described with parenterally infused agents. The authors of the Be-RITe! Registry study have demonstrated that the incidence of CIN was 71% lower using the Benephit catheter and an intrarenal infusion of fenoldopam (0.05–0.8 mg/kg/min) than would have been predicted in a group of patients at higher procedural risk due to preexisting chronic renal impairment. At first glance, this study provides compelling evidence to support TRT. However, prior to any generalized adoption of this technique, we require further evidence about the safety and efficacy of this device, the efficacy of the therapeutic agent, and the cost-effectiveness of the intervention. The very low incidence of renal artery injury (0.2%) described in this study suggests that the Benephit catheter system is safe. However, the nature of registry data collection may have led to underreporting of this complication. Furthermore, the retrospective study analysis has a number of weaknesses. The manuscript describes a subgroup of patients from the Be-RITe! Registry who had the Benephit catheter deployed before an interventional procedure and fenoldopam infused during and after the intervention. There was no standardization of the type of intervention performed, the contrast agent used, or the amount of pre/periprocedural hydration.