Baseline anemia and long term clinical outcomes in patients treated with primary percutaneous coronary intervention

Purpose: Anemia on admission is associated with worse procedural and clinical outcomes in patients with ST elevation myocardial infarction (STEMI). In this large cohort we aimed to investigate the relation of anemia on admission to long term major adverse clinical outcomes (death, myocardial infarction, stroke and rehospitalization from worsening heart failure) in patients treated with primary percutaneous coronary intervention (p-PCI) for acute STEMI. Methods: 2411 patients with STEMI that underwent p-PCI within the first 12 hours of the onset of chest pain composed the study population. Anemia was defined as hemoglobin level <13 mg/dl in males and <12 mg/dl in females. The patients were grouped as anemic (n=623) or nonanemic (n=1788). Results: The patients were older and female gender, diabetes mellitus, renal failure and cardiogenic shock were more frequent in the anemic group. Final TIMI grade 3 flow (87.5% vs 90.5%, p=0.033), myocardial blush grade 3 (38.6% vs 46.8%, p=0.001), complete ST segment resolution >70% (54.6% vs 64.7%, p<0.001) were less frequent and postprocedural left ventricular ejection fraction (45.1±8.2 vs 47.8±8.4%, p<0.001) was significantly lower in patients with anemia. While in-hospital mortality (7.9% vs 2.3%, p<0.001) and major bleeding (6.9% vs 2.5%, p<0.001) rates were higher in patients with anemia, there was no difference between the two groups with respect to reinfarction/stroke rates. At long-term follow-up (median duration: 48 months), all cause mortality (26.5% vs 10.7%, p<0.001), rehospitalization from worsening heart failure (8.9% vs 4.9%, p=0.001), stroke (2.3% vs 1.1%, p=0.028) and reinfarction (10.8% vs 7.9%, p=0.030) rates were significantly higher in the anemic group. Cox regression analysis revealed that anemia on admission is an independent predictor of major adverse cardiovascular events (death/stroke/reinfarction) at long term follow-up (Hazard ratio 3.12, 95%Confidence interval 1.15 – 6.59, p=0.011). Conclusion: Anemia on admission is associated with very high rates of in-hospital mortality and long term major adverse cardiovascular events. Anemia on admission independently predicts major adverse cardiovascular events at long term follow-up.