Abstract:Objective To investigate the glutamyltransferase (GGT) expression level in chest pain patients with normal coronary angiography (CAG) and its correlation with index of microcirculatory resistance (IMR). Methods From June 2018 to June 2019, 103 patients with highly suspected coronary heart disease admitted to our hospital were selected and divided into two groups based on the median IMR of the anterior descending coronary artery (22.32U), such as normal IMR group (n = 58) and elevated IMR group (n = 45). The levels of biochemical indexes in patients’ serum were measured and compared, the correlation analysis between the measured biochemical indexes and IMR was carried out, and multiple linear regression analysis was carried out on the influencing factors of IMR value. Results The proportion of patients with history of diabetes and hypertension in the elevated IMR group was significantly higher than that in the normal IMR group (P < 0.05). The elevated IMR group had higher GGT level and IMR value as well as lower HDL level than the normal IMR group, with statistic differences (P < 0.05). IMR was positively correlated with serum GGT (r = 0.413, P < 0.05) and negatively correlated with HDL (r = -0.326, P < 0.05). Serum GGT level was an independent correlation factor of IMR value [b = 0.248 (95% CI: 0.042, 0.871), P < 0.05]. Conclusions Serum GGT level is elevated in chest pain patients with normal CAG, and its elevation may participate the coronary microvascular dysfunction, which leads to the increase of IMR value.