Functional MR Imaging And Clinical Research On The Long-Term Adverse Outcomes Of Iodine Contrast Media

Part One Evaluation of Iodinated Contrast Media Induced Kidney Injury Using Functional Magnetic Resonance ImagingObjectives: To investigate the renal changes following intravenous administration of a high dose of either iodixanol or iopromide using functional magnetic resonance imaging (MRI) and computed tomography (CT).Materials and Methods: The study was approved by the Institutional Committee on Animal Research. Seventy-two male Sprague-Dawley rats were divided into 5 cohorts, comprising normal saline (NS),iopromide,iopromide + NS,iodixanol,and iodixanol + NS. Intravenous contrast was administrated at 8 g iodine/kg body weight. Renal CT, quantitative functional MRI of blood oxygen level dependent (BOLD) imaging and diffusion-weighted imaging (DWI) and histologic examinations were performed for 18 days following contrast administration.Statistical analysis was performed by using one-way ANOVA, Mann-Whitney test and regression analysis.Results: In the renal cortex, BOLD showed persistent elevation of R2*, DWI showed persistent suppression of apparent diffusion coefficient (ADC) after iodixanol administration over 18 days.Compared with iopromide, △R2*adj was significantly higher in the iodixanol group from 1 hour to 18 days (P < 0.04) after contrast; △ADCadj was significantly more pronounced at day 6 (P =0.01) after contrast. The iodixanol cohort also exhibited persistently higher attenuation in the renal cortex on CT and more severe microscopic renal cortical vacuolization up to 18 days.Intravenous hydration decreased the MR changes in both groups but more markedly with iodixanol.Conclusions: At high doses, iodixanol induced greater changes in renal functional MR (BOLD)relative to iopromide. Combined with longer contrast retention within the kidney, this suggests iodixanol may produce more severe and longer lasting contrast induced renal damage.Part twoLong-Term Adverse Effects for Low-Osmolar Compared with Iso-Osmolar Contrast Media After Coronary AngiographyObjectives: To compare the long-term mortality, kidney injury and cardiovascular events between low-osmolar contrast media (LOCM) and iso-osmolar contrast media (IOCM) after coronary angiography using propensity scoring in a large retrospective cohort.Materials and Methods: 12611 Cardiology patients underwent coronary angiography between January 2006 to July 2013 using either LOCM (iohexol, iopromide) or IOCM (iodixanol). For each contrast medium Primary (all-cause mortality) and Secondary outcomes (long-term renal injury and cardiovascular events beyond 90 days) was recorded. Propensity scoring with subsequent 1:1 matching (PSM) or re-weighting with inverse probability of treatment (IPTW)was applied to minimize the selection bias between groups.Results: Unadjusted all-cause mortality was significantly lower for LOCM vs IOCM (hazard ratio [HR] = 0.28; 95% CI, 0.23-0.34). After multivariate Cox regression, PSM or IPTW, all-cause mortality became comparable and lost statistical significance. LOCM subgroup analysis showed a trend to lower odds of kidney injury with iopromide vs iohexol after propensity adjustment. Chronic kidney disease (CKD) subgroup had higher mortality risk when receiving LOCM compared with IOCM (regression adjusted HR = 1.80 [95% CI: 0.95-3,42]; IPTW adjusted HR=1.57 [95% CI: 0.99-2.48]).Conclusions: After coronary angiography, patients receiving LOCM had comparable overall long-term mortality compared with IOCM after adjustment. LOCM tended to induce higher long-term mortality than IOCM in CKD cohorts.