The endothelium modulates the arterial wall mechanical response to intra-aortic balloon counterpulsation: in vivo studies

Intra-aortic balloon pump (IABP) benefits could depend on variations in the cardiovascular biomechanical properties associated with blood flow-induced endothelium-dependent changes. However, if IABP results in changes in the peripheral artery biomechanics and if the endothelium plays a role in these potential changes remains unknown. The aim of this study is to characterize acute IABP effects on peripheral artery biomechanics in control and acute heart failure (AHF) states and the role of the endothelium in IABP effects on peripheral artery biomechanics. Pressure and diameter were recorded in sheep (n= 7) iliac arteries (IAs), before and during 1:2 IABP, during four states: (i) control with intact IA; (ii) AHF with intact IA; (iii) control with de-endothelialized (DE) (mechanical rubbing) IA; and (iv) AHF with DE IA. Arterial distensibility, elastic modulus, and conduit function (CF) (1/characteristic impedance) were calculated. The results of this study include: (i) during control conditions, IABP resulted in intact IA dilatation, stiffness reduction, and CF increase; (ii) AHF induction determined a reduction in intact IA diameter and CF, and a stiffness increase. These changes reverted during IABP; (iii) the increase in IA stiffness observed after DE remained unchanged during IABP; (iv) in DE IA, AHF did not result in diameter or stiffness changes; and (v) IABP during AHF did not associate changes in diameter or stiffness in the DE IA. In conclusion, during control and AHF states, IABP results in IA dilatation and stiffness reduction. The integrity of the endothelial layer would be critical for the IABP-associated changes in IA biomechanics.