The effect of intra-aortic balloon counterpulsation on left ventricular functional recovery early after acute myocardial infarction: a randomized experimental magnetic resonance imaging study

Aims We sought to determine whether intra-aortic balloon pump (IABP) counterpulsation improves the recovery of left ventricular (LV) systolic function after reperfused acute myocardial infarction (AN). Methods and results Fourteen dogs underwent 90-min coronary artery occlusion followed by reperfusion. Seven animals were randomized to IABP counterpulsation immediately after reperfusion. Tagged, cine, and contrast-enhanced magnetic resonance imaging were used for regional and global LV functional assessment and MI characterization, respectively. Image acquisition was performed at 1 h, 6 h, and 24 h after reperfusion, during which the IABP device was paused. Animals randomized to IABP demonstrated an earlier improvement of LV ejection fraction when compared with controls (25 +/- 3 vs. 25 +/- 2% at 1 h, P = 0.91; 36 +/- 3 vs. 26 +/- 2% at 6 h, P = 0.015; and 38 +/- 3 vs. 35 +/- 1% at 24 h, P = 0.34). Regional functional analyses revealed the same behaviour among non-infarcted risk regions, i.e., earlier circumferential systolic strain improvement in the IABP group than in controls (- 5.4 +/- 0.4 vs. - 5.3 +/- 0.5% at 1 h, P = 0.86; - 12.1 +/- 1.0 vs. -6.0 +/- 0.4% at 6 h, P < 0.001; and - 13.9 +/- 1.1% vs. - 12.8 +/- 0.6% at 24 h, P = 0.40). Importantly, however, the degree of LV functional recovery 24 h after reperfusion was similar whether IABP counterpulsation was used or not. Conclusion IABP counterpulsation accelerates but does not significantly improve the recovery of LV systolic function after reperfused AMI.