Abstract: Objective  To explore the value of TIMI myocardial perfusion frame count(TMPFC) in the evaluation of microvascular obstruction after primary percutaneous coronary stenting(PCI) in patients with ST-segment elevation myocardial infarction(STEMI) and its relationship with clinical prognosis.
  Methods  A total of 200 STEMI patients with primary PCI were selected and divided into two groups according to TMPFC. Baseline clinical characteristics and angiographic characteristics of the two groups were observed, and the left ventricular ejection fraction(LVEF) and major cardiovascular adverse events(MACE) were followed up 6 months after PCI.
  Results  The incidence of diabetes, blood glucose, peak cardiac troponin I(CTnI) and MACE in the observation group was higher than that in the control group, while the incidence of pre-infarction angina, baseline LVEF and 6-month LVEF was lower than that in the control group(P＜0.05). In the observation group, the onset to first medical contact time(Onset to FMC) was longer than that in the control group; Post-stent dilation, aspiration catheter, intra-coronary platelet Ⅱb/Ⅲa receptor antagonists, multi-vessel disease, TMPFC were higher than those in the control group. The proportion of TIMI level 3, and TMPG level 3 was lower than that of the control group(P＜0.05). Onset-to-FMC and peak CTnI were independent risk factors for myocardial microcirculation obstruction(OR=1.368, 95%CI:1.149-1.627， P＜0.001; OR=1.014, 95%CI:0.951-1.082; P=0.005), and TMPFC were independent risk factors for MACE in STEMI patients after 6 months follow-up(OR=1.040, 95%CI:1.007-1.092, P=0.020).
  Conclusion  TMPFC was independent risk factors for MACE in STEMI patients undergoing PCI, and as a new quantitative evaluation index of microcirculation, TMPFC was superior to the previous imaging index of myocardial microcirculation.

Key words: myocardial infarction, percutaneous coronary intervention, TIMI myocardial perfusion frame count