Intra-aortic balloon pumping: effects on left ventricular diastolic function.
OBJECTIVE
The intra-aortic balloon pump is the most widely used form of temporary cardiac assist and often utilised in patients before and after cardiac surgery. Several effects of balloon counter-pulsation have been reported previously, but its effect on left ventricular diastolic function has not been thoroughly investigated. The aim of this study is to examine the effect of the intra-aortic balloon pump on left ventricular wall motion and transmitral flow.


METHODS
We studied 20 patients in the intensive care unit, less than 36 h following cardiac surgery. We recorded left anterior descending coronary artery and transmitral E-wave flow velocities using transesophageal echocardiography pulsed Doppler. We also recorded left ventricular long axis free-wall movement using M-mode. The intra-aortic balloon pump was set to full augmentation and recordings were made at pumping cycles 1:1, 1:2, 1:3, and when the pump was on stand-by, leaving a minimum of 5 min between the pumping modes to allow the return to control conditions. In order to eliminate time effects, the sequence of recording was varied between patients using a 4 by 4 Latin-square.


RESULTS
The peak diastolic left anterior descending coronary artery and transmitral E-wave flow velocities, and left ventricular free-wall early diastolic lengthening velocity increased significantly with intra-aortic balloon pumping cycles 1:1, 1:2 and 1:3 compared to their value with the pump on stand-by, all P < 0.001. The increase in peak transmitral E-wave flow velocity correlated with the increase in peak left anterior descending coronary artery diastolic flow velocity (r = 0.74, P = 0.02), and with the increase in left ventricular free-wall early diastolic lengthening velocity (r = 0.80, P < 0.001).


CONCLUSIONS
Using the intra-aortic balloon pump post-cardiac surgery significantly increases peak diastolic left anterior descending coronary artery flow velocities and left ventricular free-wall early diastolic lengthening velocity, whose increase explains the increase in peak transmitral E-wave velocity. Although coronary flow is epicardial and mitral flow is intracardial, their close relationship suggests an improvement in left ventricular diastolic function with intra-aortic balloon pump.
Khir
Ashraf W
AW
Department of Bioengineering, Imperial College, Exhibition Rd., London, SW7 2AZ, UK. ashraf.khir@brunel.ac.uk
Price
Susanna
S
Henein
Michael Y
MY
Parker
Kim H
KH
Pepper
John R
JR
D000368:Aged; D001021:Aortic Valve; D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000601:surgery*; D003971:Diastole; D004452:Echocardiography; D017548:Echocardiography, Transesophageal; D005260:Female; D006349:Heart Valve Diseases / Q000601:surgery*; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D007423:Intra-Aortic Balloon Pumping; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve; D011183:Postoperative Complications / Q000628:therapy*; D012039:Regional Blood Flow; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology / Q000628:therapy*