Tissue characteristics of culprit lesion and myocardial tissue-level perfusion in non-ST-segment elevation acute coronary syndromes: The EARLY-MYO-ACS study

Abstract

ObjectiveThe impact of tissue characteristics of culprit lesion on myocardial tissue-level perfusion in non-ST-segment elevation acute coronary syndrome (NSTE-ACS) remains unclear. EARLY-MYO-ACS study was a prospective observational study to investigate the relationship between pre-percutaneous coronary intervention (PCI) culprit plaque characteristics and post-PCI myocardial tissue-level perfusion with iMap intravascular ultrasound (IVUS) in NSTE-ACS patients. MethodsA total of 408 patients with coronary artery disease (246 NSTE-ACS and 162 stable angina pectoris) undergoing coronary angiography, grayscale-IVUS and iMap-IVUS were enrolled. Tissue characteristics of culprit lesion were analyzed by the iMap-IVUS system as fibrotic, lipidic, necrotic, or calcified tissue. Epicardial coronary perfusion was assessed by TIMI flow grade (TFG), and myocardial tissue-level perfusion was assessed by both TIMI myocardial perfusion grade (TMPG) and TIMI myocardial perfusion frame count (TMPFC). ResultsThe percentages of necrotic volume within the culprit lesion were significantly greater in NSTE-ACS than that in stable angina pectoris (20.8 ± 7.9% vs. 15.9 ± 7.2%, P < 0.001). Patients with impaired epicardial coronary perfusion (TFG 0–2) had higher necrotic percentage within the culprit lesion than those with normal TFG (27.9 ± 7.3% vs. 19.6 ± 7.4%, P < 0.001). Moreover, patients with impaired myocardial tissue-level perfusion (TMPG 0–2) had greater necrotic percentages within the culprit lesion than those with normal TMPG (25.0 ± 8.1% vs. 18.4 ± 6.7%, P < 0.001). Multivariate analysis revealed that iMap-derived necrotic volume percentage was independently associated with reduced post-PCI TMPG (OR 2.39 [95% CI 1.60 to 3.57], P = 0.009) and impaired post-PCI TMPFC (OR 2.89 [95% CI 1.62 to 5.16], P = 0.008). The ROC curve showed that the optimal threshold of necrotic volume percentage was 20.09% and 21.03% to predict impaired TMPG and TMPFC, respectively. ConclusionIncreased necrotic fraction of the culprit lesion is independently associated with impaired myocardial tissue-level perfusion in NSTE-ACS patients. Thus, plaque composition assessed by pre-PCI iMap-IVUS could predict post-PCI impaired myocardial tissue-level perfusion in NSTE-ACS patients (Trial Registration: ChiCTR-OCH-13003046).