The relationship between inflammation and slow coronary flow: increased red cell distribution width and serum uric acid levels

Objectives: The underlying mechanism of slow coronary flow (SCF) has yet to be elucidated. Increased red cell distribution width (RDW) and uric acid level may be indicative of an underlying inflammatory state. We aimed to investigate RDW and serum uric acid levels in patients with normal coronary arteries and SCF without stenosis. Study design: The study included 46 consecutive patients (25 males, 21 females; mean age 54 +/- 11 years) with angiographically normal coronary arteries but having SCF in all three coronary arteries. The control group consisted of 40 patients (18 males, 22 females; mean age 54 +/- 9 years) with angiographically normal coronary arteries without SCF. In both groups, RDW and serum uric acid levels were measured and compared. Results: In the SCF group, TIMI frame counts measured in the left anterior descending coronary artery, left circumflex coronary artery, and right coronary artery were significantly higher compared to the control group (p<0.05). Patients with SCF exhibited significantly higher RDW (13.4 +/- 1.6% vs. 12.6 +/- 1.2%, p=0.01) and serum uric acid levels (5.3 +/- 1.6 mg/dl vs. 4.7 +/- 1.3 mg/dl, p=0.01) compared to controls. In logistic regression analysis, uric acid [Exp(B)=1.612, 95% CI 0.206-5.35, p=0.021] and RDW [Exp(B)=1.496, 95% CI 0.403-4.72, p=0.030] were found as independent predictors of SCF. Conclusion: Our findings show that patients with SCF have significantly increased RDW and serum uric acid levels. This may help throw more light on the pathophysiological basis of SCF.