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 (AMI). 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 6h, P< 0.001; and -13.9 ± 1.1% vs. -12.8 ± 0.6% at 24h, 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.