Relationship of thrombus characteristics to the incidence of angiographically visible distal embolization in patients with ST-segment elevation myocardial infarction treated with thrombus aspiration

This study sought to investigate the association between pathological characteristics of aspirated intracoronary thrombi and the incidence of angiographically visible distal embolization (AVDE) during primary percutaneous coronary intervention (p-PCI) in patients with ST-segment elevation myocardial infarction (STEMI) treated with thrombus aspiration. AVDE of atherosclerotic and thrombotic material has been shown to impair myocardial perfusion and contribute to poor clinical outcome in patients with STEMI. Recent studies have shown that thrombus composition and size are associated with the incidence of AVDE. Aspirated thrombi from 164 STEMI patients within 12 h of symptom onset were investigated immunohistochemically using antibodies against platelets, erythrocytes, and inflammatory cells. The angiographic results showed that AVDE during p-PCI occurred in 22 (13.4%) patients. Pathological analysis revealed that thrombi from patients with AVDE had a greater erythrocyte-positive area (60 ± 15% vs. 43 ± 21%, p < 0.0005) and more myeloperoxidase-positive cells (943 ± 324 cells/mm(2) vs. 592 ± 419 cells/mm(2), p < 0.0005) than those from patients without AVDE. Thrombus size, quantified as the thrombus surface area, was positively correlated with the erythrocyte component (r = 0.362, p < 0.0001). Moreover, multivariate logistic analysis demonstrated that erythrocyte-positive area in the thrombi, glucose levels on admission, larger vessel diameter (≥ 3.5 mm), and pre-balloon dilation were independent predictors of the incidence of AVDE. This study demonstrated that the erythrocyte-rich component of aspirated thrombi may be associated with the incidence of AVDE during p-PCI in patients with STEM

Erythrocyte-rich thrombus aspirated from patients with ST-elevation myocardial infarction: association with oxidative stress and its impact on myocardial reperfusion

Recent studies have demonstrated that erythrocytes are a potential component in atheromatous lesions and thrombus formation in patients with ST-elevation myocardial infarction (STEMI). The purpose of this study was to determine the associations of red blood cell (RBC) component of coronary thrombi with oxidative stress and myocardial reperfusion. Aspirated thrombi from 178 STEMI patients within 12 h of symptom onset were investigated immunohistochemically using antibodies against platelets, RBCs, fibrin, macrophages, and neutrophils [myeloperoxidase (MPO)]. The thrombi were divided into tertiles according to the percentage of glycophorin-A-positive area: low (glycophorin-A-positive area 33; n 60), intermediate (54 to 33; n 59), and high group (epsilon 54; n 59). We also measured plasma MPO levels on admission. In the thrombi, the number of MPO-positive cells in the high-RBC group was significantly greater than that in the low-RBC group (high, 927 385; intermediate, 765 406; low, 279 220 cells/mm(2); P 0.0001). Plasma MPO levels were significantly higher in the high-RBC group than that in the low-RBC group [low 43.1 (25.071.6); intermediate 71.0 (32.9111.2); high 74.3 (31.1126.4)ng/mL; P 0.005]. Distal embolization occurred more frequently in the high-RBC group (P 0.0009). Moreover, the signs of impaired myocardial reperfusion, as indicated by incomplete ST-segment resolution (STR) and lower myocardial blush grades (MBG), and progression of left ventricular remodelling at 6 months were frequently observed in the high-RBC group (high vs. low: STR, P 0.056; MBG, P 0.01; remodelling, P 0.01). The present study demonstrated that erythrocyte-rich thrombi contain more inflammatory cells and reflect high thrombus burden, leading to impaired myocardial reperfusion in STEMI patient