Endothelial dysfunction and inflammation in patients with non-obstructive coronary arteries

Aim To determine levels of markers for endothelial dysfunction and inflammation, endothelin-1, E-selectin, and tumor necrosis factor α (TNF-α) in patients with ischemic heart disease (IHD) and non-obstructive and obstructive coronary artery (CA) disease. Material and methods This study included 32 patients with verified IHD and non-obstructive (main group, n=19) and obstructive (comparison group, n=13) CA disease. Endothelial dysfunction was diagnosed by photoplethysmography and videocapillaroscopy. Serum concentrations of endothelin-1, E-selectin, and TNF- α were measured in all patients. Results Patients with non-obstructive CA disease showed a tendency towards more pronounced endothelial dysfunction (alternative stiffness index, 7.8 m /s [6.35; 9.08]; reflection index, 36.95 % [23.4; 52.65]; capillary density following reactive hyperemia, 54.33 cap /mm2 [48.92; 75.83]; capillary density following venous occlusion, 74.33 cap /mm2 [67.83; 93.00]) compared to the comparison group (alternative stiffness index, 9.05 m/s [7.08; 10.58]; reflection index, 28.25 % [23.35; 53.75]; capillary density following reactive hyperemia, 66.83 cap /mm2 [50.83; 78.67]; capillary density following venous occlusion, 87.0 cap /mm2 [77.58; 78.67]), although statistically significant differences were not found. Concentration of endothelin-1 was significantly higher in the IHD group with non-obstructive CA disease (0.45 ng/ml [0.28;0.65]) compared to patients with CA atherosclerotic stenosis (0.35 ng/ml [0.25; 0.38], p=0.035). Concentrations of E-selectin did not significantly differ between the groups (main group, 21.1 ng/ml [18.45; 35.03]; comparison group, 28.55 ng/ml [19.08; 35.01], p=0.29). In both groups, concentrations of TNF-α did not exceed the lower threshold of sensitivity (<2.3 pg/ml). Conclusion Endothelial dysfunction and increased endothelin-1 in patients with non-obstructive CA disease along with inflammation may additionally contribute to the pathogenesis of IHD in the absence of hemodynamically significant CA stenoses. Too low level of TNFα in both groups prevented us from using it as a diagnostic marker. Further study is needed that would include a greater number of patients and a search for alternative markers.