<qa>  How many patients were excluded from current study?Among the 2952 patients with STEMI successful treatment by PCI, 395 patients 13.4 had a non-IRA CTO lesion. 18 patients were excluded from current study as they death within 7 days n6 or were not to follow-up n7. Due to unavailability of ejection fraction or renal function before CTO-PCI, ACEF score could not be calculated in 5 patients. The remaining 377 patients 95.4 were finally analyzed in the study. 279 patients performed a staged CTO-PCI attemptranging 7-28 days and was successful in 221 of them. Due to low possibility of PCI success or patients refused to perform PCI, 98 patients did not undergo the PCI attempt. The patients were then divided into successful CTO-PCI group 221 patients and failed non-attempted CTO-PCI group 156 patients. 