BACKGROUND Iron deficiency (ID) is a known co-morbidity and a potential therapeutic target in heart failure. Whether ID is frequent also in ST-segment elevation acute myocardial infarction (STEMI) patients and is associated with worse in-hospital outcomes has never been evaluated. METHODS We defined ID as a serum ferritin < 100 μg/L or transferrin saturation < 20% at hospital admission. We assessed the association between ID and the primary endpoint (a composite of in-hospital mortality and Killip class ≥ 3). We explored the potential association between ID, circulating cell-free mitochondrial DNA (mtDNA), and cardiac magnetic resonance (CMR) parameters. RESULTS Four-hundred-twenty STEMI patients undergoing primary percutaneous coronary intervention (pPCI) were included. Of them, 237 (56%) had ID. They had significantly higher admission high-sensitivity troponin and mtDNA levels as compared to non-ID patients (145 ± 35 vs. 231 ± 66 ng/L, P < 0.001; 917 [404-1748] vs. 1368 [908-4260] copies/μL; P < 0.003, respectively). A lower incidence of the primary endpoint (10% vs. 18%, P = 0.01) was observed in ID patients (adjusted OR 0.50 [95% CI 0.27-0.93]; P = 0.02). At CMR (n = 192), ID patients had a similar infarct size (21 ± 18 vs. 21 ± 19 g; P = 0.95), but a higher myocardial salvage index (0.56 ± 0.30 vs. 0.43 ± 0.27; P = 0.002), and a smaller microvascular obstruction extent (3.6 ± 2.2 vs. 6.9 ± 3.9 g; P < 0.001). CONCLUSIONS Iron deficiency is frequent in STEMI patients, it is coupled with mitochondrial injury, and, paradoxically, with a better in-hospital outcome. This unexpected clinical result seems to be associated with a smaller myocardial reperfusion injury. The mechanisms underlying our findings and their potential clinical implications warrant further investigation.

中文翻译：

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ST段抬高型心肌梗死患者中的铁缺乏症患者正在接受初次经皮冠状动脉介入治疗。

背景技术铁缺乏症（ID）是已知的合并症，并且是心力衰竭的潜在治疗靶标。尚未评估ST段抬高急性心肌梗死（STEMI）患者中ID是否也频繁发生以及是否与院内预后差相关。方法我们将ID定义为入院时血清铁蛋白<100μg/ L或转铁蛋白饱和度<20％。我们评估了ID与主要终点之间的关联（住院死亡率和Killip等级≥3的复合值）。我们探讨了ID，循环的无细胞线粒体DNA（mtDNA）和心脏磁共振（CMR）参数之间的潜在关联。结果纳入了接受原发性经皮冠状动脉介入治疗（pPCI）的240例STEMI患者。其中有237位（56％）有身分证。与非ID患者相比，他们的入院高敏感性肌钙蛋白和mtDNA水平明显更高（145±35 vs. 231±66 ng / L，P <0.001； 917 [404-1748]与1368 [908-4260]拷贝数/μL；分别为P <0.003）。ID患者的主要终点发生率较低（10％比18％，P = 0.01）（校正后的OR为0.50 [95％CI 0.27-0.93]； P = 0.02）。在CMR（n = 192）时，ID患者的梗死面积相似（21±18 vs. 21±19 g； P = 0.95），但心肌挽救指数较高（0.56±0.30 vs. 0.43±0.27； P = 0.002） ）和较小的微血管阻塞程度（3.6±2.2 vs. 6.9±3.9 g； P <0.001）。结论STEMI患者经常缺铁，并伴有线粒体损伤，而且自相矛盾的是，其住院效果更好。这种出乎意料的临床结果似乎与较小的心肌再灌注损伤有关。我们发现的潜在机制及其潜在的临床意义值得进一步研究。