hANP treatment on acute myocardial infarction patients improves myocardial perfusion of risked myocardium: Measured with N-13 ammonia PET

Objectives Recently, human atrial natriuretic peptide (hANP) is reported to have an beneficial effect in patient with acute coronary syndrome. However, the effect of hANP on myocardial perfusion is not fully understood.

Methods 12 myocardial infarction (STEMI) patients who were treated with hANP on acute stage (hANP group) and 26 patients who were not treated with hANP(control group) were studied. About 2 weeks after the onset of STEMI, N-13 ammonia PET studies (rest and ATP stress) were performed. Myocardial blood flow (MBF) of ischemia related area (IRA) at rest and with stress were quantitatively measured. LVEF at the time of reperfusion and 4 weeks after reperfusion were also measured.

Results MBF of IRA at rest was almost identical between hANP and control groups (0.62 ±0.19 vs 0.62 ±0.24 ml/min/g, p=0.89, respectively). MBF of IRA with stress tended to be better in hANP group than in control group, although the difference was not significant (1.52 ± 0.43 vs 1.23 ± 0.57 ml/min/g, p=0.21). Flow reserve of IRA tended to be higher in the hANP group than in control group (2.63 ± 0.85 vs 1.96 ± 0.74, p=0.057). LVEF at the time of reperfusion was almost similar, however LVEF at 4 weeks after reperfusion tended to show better recovery in hANP group than in control group. (64.8 ± 16.8 vs 52.7 ± 12.5 %, p=0.08).

Conclusions Treatment of STEMI patients with hANP has a beneficial effect not only on function as previously reported but also on myocardial microcirculation.