Background: Anemia is frequent among patients with cardiovascular disease and adversely affects prognosis. The objective of this analysis was to assess the impact of anemia on long-term clinical outcomes among patients undergoing percutaneous coronary intervention (PCI) with the unrestricted use of drug-eluting stents (DES).
Methods and results: Between April 2002 to March 2009, 6528 consecutive patients underwent PCI with the unrestricted use of DES. Among patients with anemia according to the criteria by the World Health Organization (WHO) (hemoglobin <130 g/L for men and <120 g/L for women, respectively) patients below the 25(th) percentile separately for men and women were defined to have severe anemia. We compared clinical outcomes among patients with severe anemia and no/mild anemia during long-term follow-up through 4 years. Whereas 21.6% of patients were found to have anemia according to the WHO definition, 347 patients (5.5%) had severe anemia (mean hemoglobin, 98±11 g/L). Severe anemia was more prevalent among the elderly (P<0.001), diabetics (P<0.001), and patients with chronic kidney disease (P<0.001). In adjusted analyses, severe anemia was associated with an increased risk of death (hazard ratio, 1.86; 95% confidence interval, 1.37-2.52; P<0.0001), cardiac death (hazard ratio, 2.32; 95% confidence interval, 1.57-3.43; P<0.0001), and myocardial infarction (hazard ratio, 2.02; 95% confidence interval, 1.36-3.01; P=0.00054) as compared with no/mild anemia without significant interaction across sexes (P=0.86) and acute coronary syndromes (P=0.61) and a trend toward a particularly high risk of mortality among anemic patients <65 years of age (P=0.07). Severe anemia resulted in a greater risk of overall definite stent thrombosis (hazard ratio, 2.59; 95% confidence interval, 1.48-4.54; P=0.00089).
Conclusions: Severe anemia is common among patients undergoing PCI with the unrestricted use of DES and adversely affects long-term prognosis, including survival.