BACKGROUND: Aortic cross-clamping during abdominal aortic aneurysm (AAA) open repair leads to development of ischemia-reperfusion injury. Electron paramagnetic resonance spectroscopy (EPR) spin-trapping is a valuable method of direct measurement of free radicals. The objective of the study was to evaluate the results of EPR as a direct method of free radical measurement and degree of inflammatory response in open operative treatment of patients with AAA and aorto-iliac occlusive disease (AIOD).

MATERIAL AND METHODS: The study was performed on a group of 32 patients with AAA and 25 patients with AIOD scheduled for open repair. Peripheral venous blood for EPR spectroscopy and for SOD, GPx, ox-LDL, Il-6, TNF-alfa, CRP, and HO-1 were harvested. Selected parameters were established accordingly to specified EPR and immunohistochemical methods and analyzed between groups by Mann-Whitney U test and Wilcoxon matched-pairs signed-ranks test with Bonferroni correction.

RESULTS: Free radicals level was correlated with the time of the aortic cross-clamping after the reperfusion of he first and second leg in AAA (r=0.7; r=0.47). ox-LDL in AAA decreased 5 min after reperfusion of the first leg (32.99 U/L, range: 14.09–77.12) and 5 min after reperfusion of the second leg (26.75 U/L, range: 11.56–82.12) and 24 h after the operation (25.85 U/L, range: 14.29–49.70). HO-1concentration increased to above the level before intervention 24 h after surgery. The activities of GPx and SOD decreased 5 min after the first-leg reperfusion in AAA. Twenty-four hours after surgery, inflammatory markers increased in AAA to CRP was 14.76 ml/l (0.23–38.55), IL-6 was 141.22 pg/ml (84.3–591.03), TNF-alfa was 6.82 pg/ml (1.76–80.01) and AIOD: CRP was 18.44 mg/l (2.56–33.14), IL-6: 184.1 pg/ml (128.46–448.03), TNF-alfa was 7.74 pg/ml (1.74–74.74).

CONCLUSIONS: EPR spin-trapping demonstrates temporarily elevated level of free radicals in early phase of reperfusion, leading to decrease antioxidants in AAA. Elevated free radical levels decreased 24 h after surgery due to various endogenous antioxidants and therapies.

Keywords: Aortic Aneurysm, Abdominal - surgery, Aorta - surgery, Electron Spin Resonance Spectroscopy - methods, Free Radicals - metabolism, Glutathione Peroxidase - metabolism, Heme Oxygenase-1 - metabolism, Ilium - surgery, Malondialdehyde - blood, Reconstructive Surgical Procedures, Superoxide Dismutase - metabolism, Vascular Surgical Procedures