The outcomes in STEMI patients with high thrombus burden treated by deferred versus immediate stent implantation in primary percutaneous coronary intervention: a prospective cohort study

Background: No-/slow-reflow indicates worse outcomes in ST-elevation myocardial infarction (STEMI) patients with high thrombus burden. We examined whether deferred stenting (DS) strategy reduces no-/slow-reflow or major adverse cardiovascular events (MACEs) in primary percutaneous coronary intervention (pPCI) for patients with acute STEMI and high thrombus burden.

Methods: We performed an open-label, multi-center, prospective cohort study among eligible patients with acute STEMI and high thrombus burden who further received pPCI. All participants received PCI with DS (second procedure performed within 48-72 h) or immediate-stenting (IS) strategy. The primary outcome was the incidence of no-/slow-reflow. We evaluated MACEs and bleeding events during hospitalization and at 30- and 90-day follow-ups.

Results: We recruited 245 patients to this study, including 51 with DS and 194 with IS. Baseline clinical characters were comparable between the 2 strategies. Incidence of no-/slow-reflow defined by thrombolysis in myocardial infarction (TIMI) flow grade was not significantly different between the 2 strategies [DS: 5 (9.8%), IS: 33 (17.0%), P=0.21]. No-/slow-reflow by TIMI myocardial perfusion grade (TMPG) was less prevalent in DS [20 (39.2%) vs. 107 (55.2%), P=0.04]. No significant differences were found in recurrence of myocardial infarction (P=0.56), cardiac death (P=0.37), all-cause mortality (P=0.37), heart failure-induced readmission (P=0.35), or bleeding (P=0.61) between the 2 strategies in-hospital, and at 30- and 90-day follow-up.

Conclusions: In STEMI patients with high thrombus burden who underwent pPCI, DS strategy reduced no-/slow-reflow of microcirculation. However, DS strategy did not reduce incidence of MACEs or bleeding.