The way the intra-aortic balloon catheter moves within the aorta as a possible mechanism of balloon associated morbidity.

This study set off to investigate which mode of weaning of an intra-aortic balloon pump (IABP) produces more aortic trauma. With the use of a perfusion pump, an intact porcine aorta with an IABP in situ, was studied. Angioscopic images of the interior of the aorta were obtained. Whilst keeping steady blood pressure and flow, an 'aortic impact score' was calculated. Endoscopically there is a 'whipping' effect of the balloon shaft on the lateral aortic wall, which appears to be prominent in 1:3 mode. The aortic impact score at 0.5, 6 and 12 h during the experiments was: (1) When weaning by mode: a) 1:1 3.3+/-0.6, 4.0+/-1.0 and 4.3+/-0.6; b) 1:2 4.7+/-0.6, 6.7+/-0.6 and 7.0+/-0.0; c) 1:3 8.7+/-0.6, 11+/-1.0 and 11.7+/-0.6. (2) Weaning by augmentation: a) 75% 2.3+/-0.6, 2.7+/-0.6 and 3.0+/-0.0; b) 50% 1.3+/-0.6, 1.3+/-0.6 and 1.7+/-0.6. An increasing score was observed while weaning by mode (P<0.05). The 1:3 mode produces marked intimal disruption that worsens with time.