The visceral perfusion system and distal bypass during thoracoabdominal aneurysm surgery: an alternative for physiological blood flow?

There are potential benefits to addition of visceral organ perfusion, by means of a 9-Fr. catheter system (octopus), to distal aortic perfusion during thoracoabdominal aneurysm surgery. However, in the literature there are reports of adverse effects. The authors therefore compared two groups of patients who underwent thoracoabdominal aneurysm surgery with and without visceral organ perfusion. In the group in which the visceral perfusion was applied, the use of platelets (26 versus 11 units; P < 0.05), fresh frozen plasma (3.4 versus 1.5 units; P < 0.05) and packed cells (20 versus 8 units, P < 0.05) was significantly increased. An equal number of patients in both groups developed renal failure postoperatively. An explanation for this adverse effect can be found in the high shear rates in the catheters used, mainly as a result of the small diameter. High shear rates cause haemolysis. Also, the flow through the catheters is insufficient to maintain adequate perfusion of the visceral organs. A higher flow in these catheters would result in an even higher shear rate. It is therefore concluded that coagulopathy and insufficient bloodflow is caused by the small internal diameter of the catheters, which renders the device insufficient.