Effect Of Blood Pressure On Paraplegia During Endovascular Thoracic Aorta Repair

Objective: Set up a multi-factors system for monitoring and evaluating spinal cord ischemia and make a canine EVR model with stent-graft. Probe the effect of blood pressure on paraplegia during endovascular TA repair with the model.Methods: (1) To design and manufacture the stent-grafts which are fit for the ascending aorta in canine through measuring the radiography result. Using a special delivery, we release the stent-graft to TA from iliac artery. (2) 20 canines were used, which were randomly divided into group A (Hypertension), B (Hypotension), C (Normal) and D (Vacant control group). (3) Arterial blood and CSF samples were carried out to determine PH, pCO2, glucose, lactate and NSE at preoperation and postoperation 15, 30, 60 and 90 mins. SEP was measured at the same intervals. All animals were evaluated neurologically at postoperation 24, 48 and 72 hours. At last canines were sacrificed for spinal cord pathologic assessment at postoperation 1 month. (4) Statistical analysis (p ≤ 0.05).Results:(1) The average size of stent-graft fitting for 23-25kg dogs are that proximal diameter is 20mm, distal diameter is 12mm, length is 250mm. The biggest diameter is 18F that could pass through the iliac artery.(2) In operation groups, the level of lactate in CSF at postoperation is higher than preoperation. And in different groups p > 0.05 at the same time.(3) In all groups, the level of glucose in CSF has no singnificantly difference which is similar with in multigroups at same time.(4) In operation groups, the level of NSE in CSF at postoperation 60, 90 mins are higher than preoperation. At 30mins, NSE in B group is more than in C group. At 60, 90 mins, NSE in A group is less than B. However, between A and C groupp > 0.05 similar with C and B group.(5) In operation groups, the level of pCO2 in CSF at postoperation 60, 90 mins are higher than preoperation. At 60, 90mins, pCO2 in A group is less than in B group. At 60mins, pCO2 in C group is less than B.(6) In A group, the level of pCO2 in CSF 60 mins is lower than preoperation. In different groups p > 0.05 at the same time.(7) Neurologic assessment: In every group, p > 0.05 at different times. At 24 hours, there is singnificantly difference between B and D group.(8) SEP: In operation groups, there are singnificantly differences at different times similar. At same time, between different groups there are singnificantly differences: the ratio of amplitude is D > A > C> B, the incubation period is D < A