The relationship between red blood cell distribution width and myocardial ischemia in dobutamine stress echocardiography.

Objectives: Although elevated red blood cell distribution width (RDW) is associated with adverse outcomes in patients with cardiovascular disease, its role in demonstrating the presence and extent of myocardial ischemia for coronary artery disease is not known. The purpose of this study is to investigate the relationship between RDW and myocardial ischemia by using dobutamine stress echocardiography (DSE).

Methods: A total of 917 patients were included in this prospective study. A complete blood analysis was performed for RDW before DSE. According to DSE results, patients were divided into two groups: DSE negative and DSE positive. According to the number of ischemic segments in DSE, patients were divided into three groups: no-ischemic segment, 1-3 ischemic segments, and ≥4 ischemic segments. In addition, coronary angiography results of DSE-positive groups were assessed in respect of RDW.

Results: The RDW of the DSE-positive group (n=277) was higher than for the DSE-negative group (n=640) (13.5±1.5 vs. 12.7±1.3%, P<0.001, respectively). Elevated RDW values were also related to higher number of ischemic segments (no-ischemic segment group: 12.7±1.3, 1-3 ischemic segments group: 13.2±1.5, and ≥4 ischemic segments group: 14.2±1.3, P<0.001). A receiver operating curve analysis showed a cut-off value of RDW greater than 13.5% for predicting myocardial ischemia (sensitivity: 57.0%, specificity: 77.8%, positive predictive value: 52.7%, negative predictive value: 80.7%). In addition, positive predictive value of DSE was increased from 82.4 to 94.2% for detecting coronary artery disease by coronary angiography, when RDW (>13.5%) was used.

Conclusion: RDW is related to the presence and extent of myocardial ischemia in DSE. A high RDW increases the diagnostic accuracy of DSE.