Discerning aortic waves during intra-aortic balloon pumping and their relation to benefits of counterpulsation in humans

Abstract

An explanation of the mechanisms leading to the beneficial hemodynamic effects of the intra-aortic balloon pump (IABP) is lacking. We hypothesized that inflation and deflation of the balloon would generate a compression (BCW) and an expansion (BEW) wave, respectively, which, when analyzed with wave intensity analysis, could be used to explain the hemodynamic benefits of IABP support. Simultaneous ascending aortic pressure (Pao) and flow rate (Qao) were recorded in 25 patients during control conditions and with IABP support of 1:1 and 1:2. Diastolic aortic pressure augmentation (Paug) and end-diastolic aortic pressure (ED Pao) reduction were calculated from Pao. Energies of the BCW and BEW were obtained by integrating the wave intensity contour over time. Paug was 19.1 mmHg (SD 13.6) during 1:2 support. During 1:1 support significantly higher Paug of 21.1 mmHg (SD 13.4) was achieved (P < 0.001). ED Pao decreased from 50.9 mmHg (SD 15.1) to 43.9 mmHg (SD 15.7) (P < 0.0001) during 1:1 assistance and the decrease was not statistically different with 1:2. During 1:1 support the energy of BCW was correlated positively to Paug (r = 0.83, P < 0.0001) and energy of the BEW correlated negatively to ED Pao (r = 0.78, P < 0.005); these relationships were not statistically different during 1:2. In conclusion, the energies of the BCW and BEW are directly related to Paug and ED Pao, which are the conventional hemodynamic parameters indicating IABP benefits. These findings imply a cause and effect mechanism between the energies of BCW and BEW, and IABP hemodynamic effects.

Microvascular response to metabolic and pressure challenge in the human coronary circulation

“…Considering the presence of strong perturbances such as during ECP, it is questionable whether a conversion from radial to central pressure using the inverse aortic-to-radial H439 CORONARY RESPONSE TO METABOLIC AND PRESSURE CHALLENGE transfer function proposed by Chen et al (9) would result in reasonable central pressure curves. The nature of the diastolic pulse wave is not fundamentally different in the radial and coronary artery: in both cases, it consists of a forward-propagating compression wave (25,38). Although the absolute pressure values may slightly differ in the coronary arteries, we believe that radial pressure measurement do no hamper the coronary analysis in this case.…”

Wave intensity analysis in the great arteries – What has been learnt during the last 25 years? Part 1

“…aortic WIa during counterpulsation has revealed the presence of additional backward-travelling aortic waves during diastole [42][43][44] . The energies of these waves are correlated to conventional hemodynamic parameters used for the assessment of counterpulsation benefit.…”

Novel wave power analysis linking pressure-flow waves, wave potential, and the forward and backward components of hydraulic power

“…Although now widely used to analyze experimental, numerical, and, increasingly, clinical research data (2,6,12,13,15,22,34,39,43,47), there are two drawbacks to the method. First, in some clinical and many experimental settings, volumetric blood flow, rather than blood velocity, is the primary measured quantity.…”