AN EXPERIMENTAL-STUDY OF INTRA AORTIC BALLOON PUMPING WITHIN THE INTACT HUMAN AORTA

Objective: Intra-aortic balloon pumping is a therapeutic technique whi ch carries a significant morbidity related to the intel action between the balloon catheter and the aorta. The aim of this study was to visu alise directly the dynamic action of the balloon catheter within the c adaveric human aorta in an artificial circulation. Methods: An artific ial circulation was constructed using of PVC tubing, a filter and a ro ller pump. A series of five intact cadaveric human aortas were then in dividually studied by placing each in series within the circuit. A bal loon catheter was advanced via the left common iliac artery into the d escending aorta under direct angioscopic vision. Balloon pumping was t hen commenced. The circuit was perfused with normal saline at a flow r ate of 3 1/min. Pump actions of 1:1 and 1:2 were simulated. Each aorta at the end of the experiment was subjected to histological examinatio n. Result: The balloon only appeared to make direct contact with the w all of the aorta during deflation when it was swept to one side by the circulating fluid. During maximal inflation the only points of contac t were the tip of the catheter and the entry site. Side branches of th e aorta were not occluded by the balloon. There was considerable ather omatous debris visualised within the lumen of the aorta. Atheromatous plaques were seen to fissure and disrupt by a pressure wave action and not by direct contact with the balloon. Conclusion: The balloon cathe ter moves relative to the wall of the aorta during inflation and dt na tion. Contact between the balloon and the aorta only occurs during def lation. Side branches of the aorta are not occluded by the catheter. P laque disruption and embolus formation appear to result from pressure wave action rather than direct contact with the balloon. This may have implications for future balloon design. Further investigation of this poorly understood interaction between the balloon and the aortic wall is required. (C) 1997 Elsevier Science B.V.