Background: Microvascular reperfusion following percutaneous coronary intervention (PCI) is associated with the prognosis of patients with ST-segment elevation myocardial infarction (STEMI). We investigated how plaque characteristics detected by optical coherence tomography (OCT) in STEMI patients affect the status of the microcirculation during PCI.Methods and Results: This retrospective, single-center study was a post hoc analysis basedon the multicenter SALVAGE randomized control trial (NCT03581513) that enrolled 629 STEMI patients, and finally we enrolled 235 patients who underwent PCI and pre-intervention OCT. Microvascular perfusion was evaluated using the Thrombolysis in Myocardial Infarction (TIMI) myocardial perfusion frame count (TMPFC). Patients were divided into 3 groups based on the change in TMPFC from before to after PCI: improving TMPFC (n=11; 4.7%), stable TMPFC (n=182; 77.4%), and worsening TMPFC group (n=42; 17.9%). The proportion of patients with a microcirculation dysfunction before reperfusion was 11.9%, which increased significantly by (P=0.079) 8.5% to 20.4% after reperfusion. Compared with plaque characteristics in the stable and worsening TMPFC groups, the improving TMPFC group had fewer thrombi (90.7% and 90.5% vs. 89.4%, respectively; P=0.018), a lower proportion of plaque rupture (66.5% and 66.3% vs. 54.5%, respectively; P=0.029), and a lower proportion of lipid-rich plaques (89.6% and 88.1% vs. 63.6%, respectively; P=0.036).
Conclusions: PCI may not always achieve complete myocardial reperfusion. Thrombi, plaque rupture, and lipid-rich plaques detected by OCT can indicate microcirculation dysfunction during the reperfusion period.
Keywords: Microvascular dysfunction; Optical coherence tomography; Plaque characteristics; ST-segment elevation myocardial infarction.