A technique that uses partial selective antegrade perfusion (SCP) with aortic arch aneurysms was described in the 1980s (Frist et al.1986). The SCP involves distal clamping of the aorta along with cannulation of the innominate, the left common carotid, and subclavian arteries. These arteries are perfused in an antegrade fashion in order to take advantage of the intrisic cerebral autoregulation of blood flow that ensures a constant supply of oxygen over a broad range of metabolic demands and hydrostatic pressures (Ergin ey al.1994).The current trend is to perfuse at least the innominate and left carotid arteries with a dedicated pump in a system with flows determinded by trget presures measured at distal sites. A system of low flow and profoundly hypothermic cerebral perfusion used while keeping the rest of body at moderate hypothermia in attempt to reduce the time required for pump rewarming (Bachet ey al.1991).
Selective cerebral perfusion extends the "safe"period during which conventional systemic perfusion may be interrupted and reduces the risk of cerebral ischemia. ( Matsuda ey al.1989).
Preservation of the cerebral autoregulatory system by SCP alloows for longer periods of aortic arch repair. Any impairment of this autoregulation may lead to reperfusion injuries associated with regional over - and under-perfusion of the affected cerebral areas (Ergin et al.1994). Selective cerebral perfusion is more complicated technically than hypothermic circulatory arrest. Additional time and manipulation are required to isolate and cannulate the arch branches, and this may damage fragile arteries or dislodge atheromatous debris into the cerebral circulation. The use of SCP is limited in patients with severe carotid or brachiocephalic desease,traumatic aortic aneurysms, aortic rupture, infection or aortic dissection involving arch vessels, in patient with previous aortic, cardiac or mediastinal operations, or for thouse who require arrest before performing a sternotomy (Frist et al. 1986).