Ramanathan Ganesh, Olynyk John K, Ferrari Paolo
Department of Nephrology, Prince of Wales Hospital, Sydney, New South Wales, Australia.
Department of Gastroenterology, Fiona Stanley and Fremantle Hospitals, Perth, Western Australia, Australia.
Hemodial Int. 2017 Jun;21 Suppl 1:S58-S67. doi: 10.1111/hdi.12555. Epub 2017 Mar 22.
Absolute or functional iron (Fe) deficiency is an important determinant of anemia in hemodialysis patients and parenteral Fe is routinely used to treat this condition in conjunction with erythropoiesis stimulating agents. While restoration of hemoglobin toward the target range is a good outcome of Fe replacement, it is well known that Fe overload and toxicity may be adverse consequences of this therapy. Dialysis clinical practice guidelines recommend tailoring Fe therapy based on transferrin saturation and serum ferritin levels. Unfortunately, serum Fe markers may not accurately reflect the amount of Fe in the body, because factors such as infections, inflammation, or malignancy can alter serum ferritin levels. Some recent trials in dialysis patients receiving high intravenous Fe doses have shown increased cardiovascular morbidity and mortality and studies using magnetic resonance imaging (MRI) in this population have shown excessive tissue liver iron content (LIC) suggesting Fe overload. While LIC measured by MRI correlates well with LIC quantitated by liver biopsy, it only represents a surrogate marker for total body Fe and its clinical relevance in dialysis patients in terms of mortality and morbidity remains to be demonstrated. Nevertheless, these recent findings challenge the use of current serum Fe markers recommended by clinical guidelines to guide safe Fe therapy in dialysis patients. While not yet established for the routine screening of dialysis patients for Fe overload, MRI should be considered in patients who have received a high cumulative dose of intravenous Fe, or have long cumulative dialysis vintage. Further studies are needed to assess how MRI will alter management.
绝对铁缺乏或功能性铁缺乏是血液透析患者贫血的重要决定因素，肠外铁剂通常与促红细胞生成素联合用于治疗这种情况。虽然将血红蛋白恢复到目标范围是铁替代治疗的良好结果，但众所周知，铁过载和毒性可能是这种治疗的不良后果。透析临床实践指南建议根据转铁蛋白饱和度和血清铁蛋白水平调整铁剂治疗。不幸的是，血清铁标志物可能无法准确反映体内铁的含量，因为感染、炎症或恶性肿瘤等因素会改变血清铁蛋白水平。最近一些针对接受高剂量静脉铁剂的透析患者的试验显示心血管发病率和死亡率增加，而在该人群中使用磁共振成像（MRI）的研究显示肝脏组织铁含量（LIC）过高，提示铁过载。虽然通过MRI测量的LIC与通过肝活检定量的LIC相关性良好，但它仅代表全身铁的替代标志物，其在透析患者中的死亡率和发病率方面的临床相关性仍有待证实。然而，这些最新发现对临床指南推荐的当前血清铁标志物用于指导透析患者安全铁剂治疗提出了挑战。虽然尚未确定将MRI用于常规筛查透析患者的铁过载，但对于接受高累积剂量静脉铁剂或长期累积透析时间的患者，应考虑使用MRI。需要进一步研究以评估MRI将如何改变治疗管理。
