A CFD investigation of intra-aortic balloon pump assist ratio effects on aortic hemodynamics

Intra-aortic balloon pump (IABP) is a mechanical circulatory support approach used in case of several cardiac diseases and a challenge of IABP therapy is the weaning process accomplished by decreasing the assist ratio. However, the impact of weaning on aortic hemodynamics on organs perfusions is not well known. Aim of this study was to evaluate and compare the global effects of IABP assistance frequencies on hemodynamics and perfusions in a patient-specific geometry by means of the computational fluid dynamics (CFD). A 3D aorta model was obtained from CT images using segmentation and reverse engineering techniques. The balloon was modeled and positioned in the descending aorta as in clinical practice and its inflation/deflation behavior was realized with a parametric study. Four assist ratios have been investigated: full assistance (1:1), partial assistances (1:2 and 1:3) and weak assistance (1:4). To perform the comparison, same boundary conditions were applied. Our results highlighted that the presence of balloon in aorta modifies significantly its hemodynamics and that the four assist ratios generate different perfusions in the human districts. Data suggested also that the biggest difference occurs between 1:2 and 1:3 frequencies and that 1:4 ratio is more suitable for the weaning of counterpulsation treatment than the 1:3 ratio. This first CFD analysis of IABP weaning increases information and knowledge on hemodynamics and organs perfusions.