Oxygen free radicals in abdominal aortic surgery. An experimental study.

BACKGROUND

In aortic reconstruction, intestinal and muscular ischaemia in the lower limbs occurs during cross-clamping of the aorta. After restoration of blood flow, reactive oxygen intermediates may lead to systemic injury to local or remote organs. In this study we investigated the usefulness of a shunt and vitamin E administration against the oxidant load generated in ischaemia-reperfusion phases.

METHODS

In three groups of pigs (n=16) aortic reconstruction was simulated. In Group A (n=5) clamping of the infrarenal aorta was performed for 2 hours. In Group B (n=6), during aortic cross-clamping, a shunt was used to give flow to the inferior mesenteric and internal iliac arteries. In Group C (n=5) vitamin E was administered before aortic cross-clamping. In all groups we evaluated sigmoid histology after reperfusion, while the oxidant load was estimated by measuring superoxide dismutase (SOD) activity in blood samples from portal and jugular vein.

RESULTS

Histology of the sigmoid revealed increased postischaemic injuries in Group A, while the protective effect of shunt and vitamin E was apparent in Group B and C, respectively. SOD activity was minimized in Group C.

CONCLUSIONS

Vitamin E protected the sigmoid from postischaemic injury and is responsible for the decreased levels of SOD activity.