Haemodynamic and metabolic response to endovascular repair of infra-renal aortic aneurysms

We have examined whether or not endovascular insertion of a bifurcated aorto-iliac graft resulted in greater intraoperative haemodynamic and metabolic stability than that achieved during conventional open graft placement. We studied 20 patients prospectively during surgery for asymptomatic infra-renal aortic aneurysm. All patients received the same anaesthetic technique. Haemodynamic data were collected continuously using indwelling radial artery and pulmonary artery catheters, allowing calculation of mean arterial pressure (MAP), cardiac output (CO) and systemic vascular resistance (SVR). Blood samples were obtained for measurement of serum lactate concentrations. Variables were compared within each group before and after specific critical events, namely occlusion of femoral or aortic blood flow, or both, and sequential reperfusion of each lower limb. Patients undergoing open repair showed significant changes in CO, MAP and SVR related to aortic cross-clamping and lower limb reperfusion, and a significant increase in blood lactate concentration after distal tissue reperfusion. The only significant changes during endovascular repair were a transient increase in SVR secondary to application of the femoral artery clamps, and sequential decreases when each limb was reperfused. Endovascular aneurysm repair imposed significantly less intraoperative haemodynamic and metabolic stress on the patient compared with conventional open surgery.