Long-Term Adverse Effects of Low-Osmolar Compared With Iso-Osmolar Contrast Media After Coronary Angiography

The relative incidence of long-term adverse effects between low-osmolar contrast media (LOCM) and iso-osmolar contrast media (IOCM) after coronary angiography is still unclear. We analyzed cardiology patients undergoing coronary angiography from January 2006 to July 2013 using either LOCM (iohexol, iopromide) or IOCM (iodixanol) at a single institution. For each contrast medium, primary (all-cause mortality, n = 6,992) and secondary outcomes (long-term renal injury and cardiovascular events beyond 90 days, n = 2,792) were recorded. Inverse probability weighing (IPW) was applied to minimize the selection bias between groups. Unadjusted all-cause mortality was significantly lower for LOCM versus IOCM (hazard ratio [HR] 0.28, 95% CI 0.23 to 0.34). After multivariate Cox regression or IPW, all-cause mortality became comparable and lost statistical significance. Chronic kidney disease subgroup had higher mortality risk when receiving LOCM compared with IOCM (regression adjusted HR 1.80, 95% CI 0.95 to 3.42; IPW-adjusted HR 1.57, 95% CI 0.99 to 2.48). In conclusion, 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 chronic kidney disease cohorts.