Red cell distribution width as a novel prognostic marker in patients undergoing primary angioplasty for acute myocardial infarction

Abstract

Red cell distribution width (RDW), a measure of red blood cell size heterogeneity, was evaluated in patients undergoing primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI). Higher RDW is associated with mortality in patients with symptomatic cardiovascular disease, heart failure, and also in the general population. We hypothesized that admission RDW would be predictive of adverse outcomes in patients after primary PCI. Two thousand five hundred and six consecutive STEMI patients (mean age 56.6±11.8 years; 2075 males, 431 females) undergoing primary PCI were retrospectively enrolled into this study. Admission RDW was measured as part of the automated complete blood count. Patients were grouped as elevated or nonelevated RDW using the upper limit of normal value of 14.8% and were followed for in-hospital and long-term outcomes for a mean period of 1.8±1.3 years (median 21 months). A higher in-hospital mortality rate was observed among patients with elevated admission RDW (mean 16.1±1.6%) compared with those with nonelevated RDW (mean 13.4±0.8%) (7.6 vs. 3.6%, P<0.001). The long-term cardiovascular prognosis was worse for patients with elevated admission RDW (Kaplan-Meier, log-rank P<0.001). We used Cox proportional hazard models to examine the association between RDW and adverse clinical outcomes. After discharge, there were 129 deaths during follow-up. A significant association was noted between elevated admission RDW level and the adjusted risk of cardiovascular mortality (hazard ratio: 1.831, 95% confidence interval: 1.034-3.24, P=0.03). In addition, elevated admission RDW was also an independent predictor of cardiovascular mortality in the nonanemic subpopulation of patients (hazard ratio: 2.703, 95% confidence interval: 1.208-6.048, P=0.016). A high admission RDW level in patients with STEMI undergoing primary PCI was associated with increased risk for in-hospital and long-term cardiovascular mortality.