Higher red cell distribution width values are associated with impaired exercise capacity during exercise treadmill testing in patients without obstructive coronary disease: a preliminary study

摘要

BACKGROUND: Red cell distribution width (RDW) is associated with poor cardiovascular outcomes. We aimed to find out if this association could be explained by impaired exercise capacity in patients without obstructive coronary artery disease (CAD). PATIENTS AND METHODS: The patients who underwent exercise treadmill test (ETT) who have non-obstructive CAD and were free of heart failure symptoms were evaluated. Total of 132 patients were enrolled, and patients were divided into three groups according to their Metabolic Equivalent Task (MET) level measured by exercise treadmill test (ETT): Less than 7 METs (group 1), 7-10 METs (group 2) and greater than 10 METs (group 3). RESULTS: The patients in Group 1 had significantly higher RDW levels (16.46 ± 2.79) compared to Group 2 (15.05 ± 2.03) and Group 3 (14.52 ± 1.37), independent of hemoglobin and hematocrit values. Significant differences for age, gender, duration of ETT and Duke Treadmill Score were also found in proportion to the reduced exercise capacity. In multivariate analysis, only duration of ETT (β = 1.017, p = < 0.001) and RDW (β = 0.040, p = 0.026) were found as independent variables, which had statistically significant effects on METs. CONCLUSIONS: We found an independent association between RDW and exercise capacity in patients free of obstructive coronary disease suggesting that patients with elevated RDW values are expected to have impaired exercise capacity.