LAUSR

Contrast‐related adverse events remain a significant clinical complication, particularly during complex peripheral interventions, as there is notable overlap in the risk factors for peripheral arterial disease (PAD) and contrast‐induced kidney injury: namely, chronic kidney disease (CKD) and diabetes. Therefore, we often must attempt to strike a delicate balance between an acceptable percutaneous result for claudication or limb salvage and limiting the potential for contrast‐ induced complications. The use of different contrast media has produced mixed results, preventing consensus on the topic. For example, Zhao et al. showed that iso‐osmolar contrast media (IOCM) may be beneficial specifically when both diabetes and CKD are present. From et al., however, found no statistically significant difference. In their recent report, “Use of iso‐osmolar contrast media during endovascular revascularization is associated with a lower incidence of major adverse renal, cardiac, or limb events,” Prasad et al. show that using IOCM versus low‐osmolar contrast media (LOCM) is associated with a significantly lower incidence of major adverse renal, cardiac, and limb events. Their study is one of the largest non–meta‐analytic studies (>20,000 patients spanning 7 years) to examine the short‐term effects of different contrast agents used for angiography, and it includes the novel endpoint of major adverse renal and limb events. The authors make a strong argument for using IOCM in specific subgroups at risk for contrast‐ induced complications, particularly patients with diabetes and pre‐ existing kidney disease. All endovascular peripheral operators must become familiar with the different angiographic options and measures to avoid postoperative complications since the burden of risk factors for contrast‐induced complications in PAD patients is high. Several simple measures can be used to limit contrast‐induced renal injury, including periprocedural administration of IV fluids and N‐acetylcysteine. However, these measures provide only limited protection and are not applicable to procedures done on an emergency basis. There are two additional strategies to reduce contrast‐related adverse events after peripheral interventions; both involve reducing the volume of contrast during the procedure. The first measure emphasizes patient comfort. Compared with LOCM, IOCM is generally better tolerated by patients because IOCM causes less pain and sensation during contrast injections. This is particularly notable in below‐knee interventions and limb salvage cases, in which selective contrast injections in smaller‐caliber arteries are often done. Patient movement due to discomfort can significantly decrease the quality of angiograms, leading to more contrast use and time, both of which are associated with greater risk of contrast‐induced complications. For this reason, use of IOCM should be considered for all patients undergoing peripheral intervention but particularly for those undergoing below‐knee interventions. The second measure, CO2 angiography, can significantly reduce or even eliminate the use of iodinated contrast. CO2 angiography is a feasible alternative to iodinated contrast, especially in larger‐vessel interventions (in the aortoiliac, femoral, and superficial femoral arteries), where vessel visualization and overall angiographic quality are typically better. However, the quality of the images obtained is sometimes limited by operator and technician experience, and its use can be burdensome in more complex and longer interventions. In addition, its quality may be suboptimal in the smaller, below‐knee arterial system, and patient movement artifact is often magnified with CO2 angiography. Interventions for claudication and critical limb ischemia are generally more likely to lead to contrast‐induced complications due to the overlap in risk factors, but significant strides have been made by clinicians and researchers in reducing these adverse effects. The use of periprocedural intravenous fluids, N‐acetylcysteine, and CO2 angiography have reduced the incidence of contrast‐induced nephropathy. Because of the mixed results of previous studies, a consensus has not been reached as to which iodinated contrast agent should be used in high‐risk patients. The authors of this large retrospective study show that use of IOCM versus LOCM was associated with fewer major adverse cardiac, renal, and limb events. A randomized controlled trial comparing the effects of IOCM versus LOCM use on adverse renal, cardiac, and limb event rates is the next step toward establishing consensus on the topic.