Contrast sparing devices have been slowly adopted into routine patient care. Randomized trial evidence of automated contrast injectors (ACIs) has not been analyzed to evaluate the true reduction in contrast volume during coronary angiography and intervention. It is thought that by reducing the amount of contrast exposure there will be a simultaneous reduction in the risk of CIN. Therefore, we sought to synthesize published evidence on contrast sparing devices, contrast volume and incidence of contrast-induced nephropathy (CIN). We searched Medline, The Cochrane Library, and ClinicalTrials.gov. Search criteria included ACIs compared to manual injection, contrast media volume and incidence of CIN. Data was extracted by two independent reviewers. Weighted mean difference of contrast volume was calculated using random effects models in RevMan 5.4.1 software to derive a summary estimate. A total of 79,694 patients from 10 studies were included (ACI arm n= 20,099; Manual injection arm n= 59,595). On average, ACIs reduced contrast volume delivery by 45 mL per case (p < 0.001, 95%CI: -54, -35). CIN incidence was significantly reduced by 15% with an odds ratio of 0.85 (p<0.001, 95%CI: 0.78, 0.93) for those utilizing ACIs compared to manual injection. In conclusion, ACIs in angiography significantly reduces the volume of contrast delivered to the patient and the incidence of CIN.

Iloprost, a prostacyclin analogue, has been effective in preventing renal dysfunction among transplant patients. We hypothesized that iloprost is protective against renal dysfunction in different settings, in which similar underlying mechanisms of nephrotoxicity occur. We conducted a literature review, and discuss the application of iloprost in reducing acute renal insufficiency and the pathophysiological mechanisms of contrast-induced nephropathy (CIN). One proposed mechanism of CIN is prolonged renal arterial vasoconstriction, causing renal hypoperfusion, ischemia, and release of free radicals. Iloprost is an analogue of the vasodilatory prostaglandin PGI 2 . It has demonstrated cytoprotective properties in the renal transplant population by inhibiting lysosomal degradation and release of free radicals, allowing membrane stabilization. Two good-quality studies reported on iloprost and CIN. Five studies reported protective effects of iloprost in renal transplantation and 1 in coronary artery bypass grafting. Iloprost was found to be renoprotective in patients with baseline renal insufficiency who underwent coronary angiography for CIN (risk ratio [RR] = 0.32, 95% confidence interval [CI]: 0.16-0.67) and increases the weighted mean difference improvement in creatinine clearance (RR = 4.56, 95% CI: 1.82-7.30). CIN is associated with major adverse cardiac events. Preventing CIN is important for patient safety and reducing disease burden. Iloprost may reduce CIN by up to 68%. The same mechanisms of iloprost that inhibit graft dysfunction in the acute post-renal transplant and cardiopulmonary bypass setting may also contribute to preventing CIN. Large randomized controlled trials are necessary to determine the clinical efficacy of iloprost in the angiography setting. IntroductionContrast-induced nephropathy (CIN), defined as >0.5 mg/dL increase or relative increase >25% of baseline creatinine approximately 48 to 72 hours after the administration of contrast, is expected to increase in incidence proportionally with the expected increase in cardiac interventions necessary in an aging population. Risk factors include preexisting renal insufficiency, diabetic nephropathy, age