Relation Between Red Blood Cell Distribution Width And The Prognosis In Patients With Acute Coronary Syndrome

Background: Recent studies have reported that higher red blood cell distribution width (RDW) is an independent predictor of mortality in patients with heart failure and in patients with myocardial infarction without any evidence of heart failure, even after adjustment for hematocrit. Elevated RDW level has also been shown to be a strong and independent predictor of all-cause mortality in a cohort of male patients referred for coronary angiography. Besides, a high admission RDW level in patients with acute ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) was associated with increased risk for in-hospital and long-term cardiovascular mortality. However, the precise mechanism is not clear. At present, it is considered that a chronic inflammatory state and neurohumoral activation contribute to adverse clinical outcomes in patients with coronary artery disease and those with heart failure. Therefore, we hypothesized that inflammatory may be a mechanistic link between higher RDW and increased mortality in patients with acute coronary syndrome (ACS). To test our hypothesis, we examined the association of white blood count with RDW in patients with ACS.Objective: We examined the association between RDW and the risk of cardiac mortality and adverse cardiovascular outcomes in a population of people with ACS. We also examined the association of white blood count with RDW to test the hypothesis that inflammatory may be a mechanistic link between higher RDW and increased mortality in patients with ACS.Method: 1.A retrospective analysis was used. We studied 209 consecutive patients admitted to our hospital with ACS confirmed by coronary angiography from January 2009 to December 2009. Of those patients, 159 cases were diagnosed as ST-segment elevation myocardial infarction (STEMI), 16 cases were diagnosed as non ST-segment elevation myocardial infarction (NSTEMI), 34 cases were diagnosed as unstable angina (UA). All patients were followed to December 2010 or until major adverse cardiovascular events occurred. We observed the incidence of major adverse cardiovascular events during follow-up, including recurrent myocardial infarction, new heart failure, intractable angina and cardiac death.2. According to RDW measured immediately on admission, all patients were divided into two groups: lower group and higher group. Then we analyzed the relation between major adverse cardiovascular events and RDW.3. Clinical characteristics were compared between lower and higher group, then we did correlation analysis between RDW and variables that is statistically significant. To determine the variables independently associated with RDW levels, stepwise multivariate linear regression was done, including variables that correlated significantly with RDW.4. According to the result of follow-up, all patients were divided into two groups: major adverse cardiovascular events group and non major adverse cardiovascular events group. We did single factor analysis, then multivariate Logistic regression in the meaning factors to filter risk factors which influence the prognosis.Results: 1. 209 patients with ACS were enrolled, including 105 patients in higher group (RDW≥13%) and 104 patients in lower group (RDW<13%). Patients with higher RDW were more likely to be significantly older, three lesions and left main coronary disease, and more commonly had stroke history, and more advanced in white blood count, aspartate transaminase, high sensitivity C-reactive protein, GRACE score. However, mean corpuscular hemoglobin concentration and left ventricular ejection fraction were less in higher group.2. 69 patients occurred major adverse cardiovascular events during follow-up, including 15 patients had recurrent myocardial infarction, 13 patients had intractable angina, 28 patients had new heart failure, 13 patients had cardiac death. The major adverse cardiovascular events occurred more frequently among patients with higher RDW compared with those with lower RDW.3. White blood count level correlated significantly with RDW (simple correlation coefficient 0.502, partial correlation coefficient 0.466) after adjusting age, hemoglobin, mean corpuscular hemoglobin concentration, high sensitivity C-reactive protein, left ventricular ejection fraction, GRACE score and serum creatinine.4. Single factor analysis showed that age, heart rate on admission, red blood count, hemoglobin, RDW, white blood count, serum creatinine, high sensitivity C-reactive protein and left ventricular ejection fraction were risk factors of adverse outcomes. Multivariate logistic regression analysis showed that age, white blood count, left ventricular ejection fraction and RDW were associated with major adverse cardiovascular events within duration of follow-up.Conclusions: 1. RDW was a valuable factor for predicting the prognosis of patients with acute coronary syndrome.2. Inflammation may be a mechanistic link between higher RDW and increased mortality in patients with ACS.3. Age, white blood count, left ventricular ejection fraction and RDW were risk factors which can simultaneously influence the prognosis of the patients with ACS.