The association of brachial flow-mediated dilation and high-sensitivity C-reactive protein levels with Duke treadmill score in patients with suspected microvascular angina.

Background: Although earlier studies demonstrated endothelial dysfunction and systemic inflammation in patients with microvascular angina (MVA), the correlations between flow-mediated dilation (FMD), high-sensitivity C-reactive protein (hsCRP) levels and Duke treadmill score (DTS), a comprehensive index representing the severity of ischemia, have not been elucidated in this setting.

Objective: To explore the possible relationships among brachial FMD, serum hsCRP levels and DTS in MVA patients.

Methods and results: A total of 89 subjects with chest pain and a normal coronary angiogram were studied. The exercise treadmill test (ETT) was performed using the Bruce protocol for calculating the DTS. Brachial FMD and serum hsCRP levels were measured. The mean (± SD) brachial FMD was 5.45±2.24% in the group with positive ETT and 8.19±2.78% in the group with a negative ETT (P<0.001). Mean serum hsCRP levels were significantly higher in the group with positive ETT than in the group with negative ETT (4.93±1.63 mg/L versus 3.41±1.65 mg/L; P<0.001). Brachial FMD and serum hsCRP levels showed significant differences among the three groups according to DTS risk stratification. The DTS was positively correlated with FMD (r=0.532; P<0.001) and negatively correlated with hsCRP level (r= 0.461; P<0.001).

Conclusions: Brachial FMD and serum hsCRP levels may be associated with DTS in patients with MVA.