Association between Thrombolysis In Myocardial Infarction myocardial perfusion grade, biomarkers, and clinical outcomes among patients with moderate- to high-risk acute coronary syndromes: Observations from the Randomized Trial to Evaluate the Relative PR

BackgroundA variety of imaging modalities have implicated impaired myocardial perfusion in the pathogenesis of acute coronary syndromes (ACSs).MethodsWe hypothesized that an abnormal TIMI myocardial perfusion grade (TMPG 0/1/2) and an impaired coronary flow reserve (CFR) as assessed angiographically using the TIMI frame count would be associated with biomarker release, ischemia on Holter monitoring, and adverse clinical outcomes in the PROTECT-TIMI 30 trial of patients with non–ST-elevation ACS undergoing percutaneous coronary intervention (PCI).ResultsThe pre-PCI TMPG was correlated with the baseline as well as peak levels of troponin I (P < .001) and creatine kinase–MB (P < .001) and the post-PCI rise in troponin I (P = .03). The incidence of an ischemic event on Holter by 48 hours was more common among patients with an abnormal post-PCI TMPG (12.5% vs 7.0%, P = .013), and the mean normalized duration of ischemia by 24 hours after PCI on Holter monitoring trended longer among patients with an abnormal post-PCI TMPG (8.9 vs 3.2 minutes, P = .068). In multivariable analyses, an abnormal post-PCI TMPG was the strongest correlate of death, myocardial infarction, or an ischemic event by 48 hours after randomization. In contrast, the post-PCI CFR as assessed angiographically using the TIMI frame count was not associated with the baseline, peak, or absolute rise of any biomarker, Holter findings, or clinical events.ConclusionsAn abnormal TMPG, but not an angiographic CFR, is associated with biomarker status, the occurrence and duration of Holter ischemia, and adverse clinical outcomes among patients with moderate- to high-risk non–ST-elevation ACS undergoing PCI.