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This Article Full Text Full Text (PDF) All Versions of this Article: 107/5/1497    most recent 00413.2009v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Kolyva, C. Articles by Khir, A. W. PubMed PubMed Citation Articles by Kolyva, C. Articles by Khir, A. W.

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

¹Brunel Institute for Bioengineering, Brunel University, Middlesex, United Kingdom; ; ²Cardiovascular Innovation Institute, University of Louisville, Louisville, Kentucky; and ; ³Royal Brompton Hospital, London, United Kingdom

Submitted 21 April 2009 ; accepted in final form 26 August 2009

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 (P_ao) and flow rate (Q_ao) were recorded in 25 patients during control conditions and with IABP support of 1:1 and 1:2. Diastolic aortic pressure augmentation (P_aug) and end-diastolic aortic pressure (ED P_ao) reduction were calculated from P_ao. Energies of the BCW and BEW were obtained by integrating the wave intensity contour over time. P_aug was 19.1 mmHg (SD 13.6) during 1:2 support. During 1:1 support significantly higher P_aug of 21.1 mmHg (SD 13.4) was achieved (P < 0.001). ED P_ao 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 P_aug (r = 0.83, P < 0.0001) and energy of the BEW correlated negatively to ED P_ao (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 P_aug and ED P_ao, 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.

counterpulsation; waves; aortic pressure; aortic flow; wave intensity analysis