Evaluation of the time course of changes in the myocardial washout after reperfusion in patients with AMI

Objectives We examined the association between myocardial washout in early phase after intravenous injection in particular and the severity of the lesion and studied whether we could predict recovery of the cardiac function at chronic phase.

Methods 37 cases hospitalized within 24hours of AMI onset were included in the study. We performed MIBI SPECT in sub-acute phase after the PCI enforcement. Images were acquired at 5 minute(0h), one hour (1h) and six hour(6h) after injection of MIBI 740MBq and at 1 hour, the ECG gated SPECT was also performed. We also performed ECG gated SPECT at 1 hour (6m-1h) after MIBI injection 6 months later in chronic phase.

Results There were 17 cases in which a value of WO INDx showed 0 in 0h-1h ( no early washout: A group) and there were 20 cases in which the value of WO INDx was abnormal (early washout: B group). No significant difference was found in values of number of abnormal area on SPECT in 0h, 1h and 6m-1h in A group. In B group, no significant difference was found in 0h and 6m-1h, but a significant difference was found between 0h and 1h and between 1h and 6m-1h (p<0.01) (p<0.05). CPK was 1452±1006IU/l in A group and 4098±1695IU/l in B group, and it was higher in B group than in A group (p<0.01). Though BNP was as high as 384 ± 413pg/ml in sub-acute phase in A group, but the value improved to 98±109pg/ml (p<0.05) six months later. Though in B group, the value was 319 ± 260pg/ml in sub acute phase, it improved to 181±145pg/ml (p<0.05), smaller improvement was shown in B group than A group (p<0.05). LVEF was 55.4±12.4% in sub acute phase in A group and 62.7±8.8% in chronic phase with significant improvement (p<0.01). However, in B group, LVEF was 45.7±12.1% in sub-acute phase and 48.0±13.1% in chronic phase without improvement (ns).

Conclusions It was suggested that in myocardial SPECT after AMI reperfusion, early myocardial washout is associated with severity of cardiac function disorder and was useful for prediction of the future cardiac function recovery