To evaluated the value of myocardial perfusion before delayed percutaneous coronary intervention (PCI) for predicting the recovery of systolic function of patients with acute myocardial infarction (AMI).

A total of 64 patients with AMI receiving delayed PCI treatment in the First People′s Hospital of Foshan from January 2014 to June 2015 were selected. One day prior to delayed PCI, all of the patients underwent two dimensional strain to measure the longitudinal peak systolic strain (LPSS) of each left ventricular segment and the global longitudinal strain (GLS) of the left ventricle. The myocardial perfusion score (MPS) and the perfusion score index (PSI) were measured by myocardial contrast echocardiography (MCE). Left ventricular myocardial perfusions were classified as good, reduced, or absent. The two dimensional strain measurements were again conducted at 6 months after the delayed PCI to assess LPSS and GLS. The change of GLS and LPSS between one day prior to delayed PCI and six months after delayed PCI was assessed by paired t-test. The differences of LPSS among good, reduced, or absent myocardial perfusion groups were analyzed by one-way ANOVA. LSD-t test was used to compare in pairs of groups that had different values. The correlations between PSI and GLS, MPS and LPSS were assessed by Spearman′s rank-correlation test.

The GLS of all patients were higher at six months after delayed PCI than at one day prior to delayed PCI [(-15.39±7.80)% vs (-12.44±8.38)%, t=14.398, P<0.001]. The LPSS of myocardial perfusion in good, reduced and absent groups at one day prior to delayed PCI were (-2.64±5.60)%, (-6.19±6.87)% and (-12.07±5.86)%, respectively. The LPSS of myocardial perfusion in good, reduced and absent groups at six months after delayed PCI were (-2.97±4.93)%, (-11.38±7.26)% and (-15.82±5.97)%, respectively. The myocardial LPSS of left ventricular segment with good or reduced perfusion was significantly higher at six months after delayed PCI (t=13.013, 10.821, both P< 0.001), but the LPSS of left ventricular segment with absent perfusion was similar to that of pre-PCI. Whether at one day prior to delayed PCI or six months after delayed PCI, there were significant differences in LPSS parameters among the three groups (at one day prior to delayed PCI, myocardial perfusion absent vs reduced or good, t=4.201 and 11.771, both P<0.001; myocardial perfusion reduced vs good, t=12.561, P<0.001; at six months after delayed PCI, myocardial perfusion absent vs reduced or good, t=9.714 and 15.646, both P<0.001; myocardial perfusion reduced vs good, t=9.254, P<0.001). The LPSS both at one day prior to delayed PCI and six months after delayed PCI in myocardial perfusion good group> those of myocardial perfusion reduced group> those of myocardial perfusion absent group. PSI was positively correlated with GLS at both one day prior to delayed PCI and six months after delayed PCI (r=0.69, 0.72, both P<0.001). MPS was positively correlated with LPSS at both one day prior to delayed PCI and six months after delayed PCI (r=0.49 and 0.45, both P<0.001).

Myocardial perfusion before delayed PCI, monitored by MCE, is correlated well with myocardial systolic function, and may be used to predict the recovery of myocardial systolic function after delayed PCI.