Anemia and acute kidney injury in patients undergoing staged percutaneous coronary intervention for myocardial infarction

Introduction Patients hospitalized due to acute coronary syndromes (ACS), especially those with multivessel coronary artery disease, frequently present with multimorbidity. Staged percutaneous coronary intervention (PCI) is associated with a risk of acute kidney injury (AKI), commonly attributed to the volume of contrast agent administered. However, its etiology is multifactorial. Anemia is a common comorbidity that adversely affects the prognosis and may significantly modulate the overall risk of AKI, influencing both its occurrence and the impact of other contributing factors. Given the substantial prevalence of anemia among patients with myocardial infarction, investigating the pathophysiological mechanisms underlying AKI in this population is warranted. Objective To evaluate risk factors for AKI in patients with ACS and anemia undergoing staged percutaneous coronary intervention. Methods This retrospective study included patients hospitalized at the Cardiology Clinic due to myocardial infarction and treated with staged PCI. Patients receiving chronic renal replacement therapy were excluded. Among patients with anemia, comparative analysis was performed between those who developed AKI during hospitalization (n=38, 45.8%) and those who did not (n=43, 54.2%). Results Out of 305 patients included in the registry, anemia on admission was identified in 83 patients (27.2%). The incidence of AKI was significantly higher in anemic patients compared to those without anemia: 38 (45.8%) vs. 58 (26.1%, p=0.001). AKI after both the first and second PCI stages was more frequently observed in the anemic group: 8 (9.6%) vs. 3 (1.4%, p=0.006). Among anemic patients, AKI occurrence was associated with a history of chronic kidney disease (p=0.008), lower left ventricular ejection fraction (LVEF) (p=0.005), worse clinical status assessed by Killip-Kimball classification (p=0.008), higher incidence of shock (p=0.055), and approximately 20% higher baseline creatinine levels (p=0.030). Multivariate logistic regression identified chronic kidney disease (hazard ratio [HR] 3.75; 95% confidence interval [CI]: 1.36–10.28, p=0.010) and Killip-Kimball class (HR 2.47; 95% CI: 1.25–4.90, p=0.009) as independent risk factors for AKI. Patients with anemia and AKI experienced significantly longer hospital stays (median 9 vs. 5 days, p=0.015) and higher discharge creatinine levels, approximately 50% greater than those without AKI (p<0.0001). Conclusions Anemia is associated with an increased incidence of AKI in patients with ACS undergoing staged PCI. Principal factors elevating AKI risk in anemic patients include chronic kidney disease, worse clinical status reflected by lower LVEF and higher Killip-Kimball class, and elevated baseline creatinine levels. AKI in this subgroup leads to aggravated renal dysfunction and prolonged hospitalization.