Predictive value of red blood cell distribution width for the long-term prognosis of patients with acute ST elevation myocardial infarction after percutaneous coronary intervention

Objective: To study the predictive value of red blood cell distribution width (RDW) for the long-term prognosis of patients with acute ST elevation myocardial infarction (STEMI) after percutaneous coronary intervention (PCI). Methods: A total of 309 patients with acute ST elevation myocardial infarction (STEMI) who underwent PCI in our hospital from Nov. 2009 to Aug. 2013 were selected as the subjects. According to the upper limit of the normal range of RDW (14%), patients were divided into the high RDW group and the low RDW group. Death was considered as the primary endpoint of the study, and major adverse cardiovascular events (MACE) as the secondary endpoint. Kaplan-Meier survival analysis was used to determine the difference in the cumulative survival rate between the two RDW groups. Multivariate Cox regression analysis was used to study the independent influencing factors in STEMI patients after PCI. Results: The longest follow-up time was 40 months; the median follow-up time was 10 (324) months. The mortality rate of patients in the high RDW group was higher than that of patients in the low RDW group (P=0.018). The incidence of MACE (P=0.003) and mortality rate (P=0.029) of patients in the high RDW group was significantly higher than those of the patients in the low RDW group. However, there was no significant difference in the incidence of recurrent myocardial infarction event, target vessel revascularization, and stroke between the high and low RDW groups. Multivariate Cox regression analysis showed that age (hazard ratio [HR]: 1.06; 95% confidence interval [95% CI]: 1.02-1.08; P=0.004), white blood cells (HR: 1.16; 95% CI: 1.07-1.25; P<0.001), high RDW (HR: 2.21, 95% CI: 1.23-4.67, P=0.023), creatinine (HR: 1.007, 95% CI: 1.003-1.011, P=0.001), and left ventricular ejection fraction (HR: 0.93; 95% CI: 0.89-0.98; P=0.002) were independent factors influencing the mortality rate of STEMI patients. Kaplan-Meier survival analysis showed that the cumulative survival rate of the patients in the high RDW group was significantly lower than that of the patients in the low RDW group (Log Rank =8.00, P=0.005). The cumulative mortality rate was 19.5% in the high RDW group and 8.1% in the low RDW group. The difference in the cumulative mortality rate between the two groups was significant (χ2=8.80, P=0.003). Conclusion: Our results suggest that high RDW is an independent risk factor for long-term mortality of STEMI patients after PCI and it can be used for risk stratification in patients after admission.