Microvascular dysfunction after primary
percutaneous coronary intervention (PCI) augments myocardial damage and prognosis in acute
myocardial infarction. However, the relationship between baseline
anemia and coronary microcirculation in patients with
ST-segment elevation myocardial infarction (
STEMI) remains unclear. We performed primary PCI in 337 consecutive patients with
STEMI.
Anemia was defined as a
hemoglobin level < 13 g/dL in men and < 12 g/dL in women. Admission
anemia was present in 17.5% of the patients enrolled. Data on epicardial coronary flow, STsegment resolution (STR) on electrocardiography, myocardial injury, and the incidence of
adverse cardiac events defined as
cardiac death or hospitalization for
congestive heart failure were analyzed. The median follow-up period was 54.8 months. Despite comparable epicardial coronary flow, the rate of STR ≥ 50% was lower in anemic patients compared with non-anemic patients (55.9% versus 71.2%, P = 0.02). On multivariate logistic regression analysis, baseline
anemia was an independent negative predictor of STR ≥ 50% (odds ratio, 0.53; 95% confidence interval: 0.31-0.92, P = 0.03). Moreover, anemic patients had higher maximum
creatine kinase levels normalized for body surface area (2,215 ± 1,318 IU/L/m(2) versus 1,797 ± 1,199 IU/L/m(2), P = 0.047).
Anemia remained an independent significant predictor of adverse events on multivariate Cox proportional hazard analysis (hazard ratio, 2.34; 95% confidence interval: 1.01-5.64, P = 0.048). In conclusion, admission
anemia was related to microcirculatory dysfunction and poor prognosis in patients with
STEMI. The decreased
oxygen delivery might exacerbate microvascular function.