急性心肌梗死冠状动脉内抽吸物的病理分析

Pathological analysis of aspirated materials from the culprit lesion in patients with acute myocardial infarction

目的对急性ST段抬高心肌梗死（STEMI）急诊经皮冠状动脉介入治疗术（PCI）中血栓抽吸获得的样本进行病理分析并探讨其临床意义。方法搜集STEMI患者急诊PCI中的可见抽吸物，根据光镜下病理所见将其分为红细胞为主血栓（红血栓）、血小板／纤维素为主血栓（白血栓）、混合血栓（红细胞与血小板／纤维素含量近似）、斑块和血浆析出物成分。根据血栓时相将其分为新鲜血栓（〈1d）、裂解血栓（1～5d）、新鲜＋裂解血栓和机化血栓（〉5d）。根据光镜下有无斑块物质分为无斑块组和斑块组，探讨清除斑块物质对心肌再灌注指标如心肌呈色分级（MBG）、心肌标志物估测的梗死面积[肌酸激酶（CK）、CK同工酶（CK-MB）峰值]、术后16h内左心室舒张末内径（LVEDD）和左心室射血分数（LVEF）的影响。结果共搜集49例单纯抽吸导管血栓清除术的可见抽吸物，光镜下确认46例有血栓成分，3例仅有斑块成分。红血栓、白血栓和混合血栓比例分别为41．3％（19／46）、30．4％（14／46）和28．2％（13／46）。新鲜血栓、裂解血栓、新鲜＋裂解血栓和机化血栓比例分别为47．8％（22／46）、32．6％（15／46）、10．9％（5／46）和8．7％（4／46）。占57．1％（28／49）的样本中可见粥样斑块成分，还可见破裂斑块伴血栓形成、纤维斑块和正常内膜，比例分别为8．2％（4／49）、6．1％（3／49）和2．0％（1／49）。无斑块组（12=21）和斑块组（n=28）之间基线资料差异无统计学意义（均P〉0．05），MBG3级比例[52．4％（11／21）比82．1％（23／28）]、CK峰值[（2629±2013）U／L比（1705±1647）U／L]、CK—MB峰值[（258±215）μg／L比（146±136）μg/L]和术后16h内LVEF（0．52±0．08比0．59±0．10）差异均有统计学意义（均P〈0．05）。结论STEMI患者急诊PCI中采用单纯抽吸导管可有效清除血栓和部分斑块物质，改善心肌再灌注和心功能，并限制梗死面积。急诊PCI中采用抽吸导管清除斑块物质即斑块减容可能是血栓抽吸改善心肌再灌注、限制梗死面积和预后的重要机制之一。

Objective To analyze the components of retrieved materials from the culprit lesion in ST-segment elevation myocardial infarction （STEMI） patients by manual aspiration during primary percutaneous coronary intervention （ PCI）. Methods Visible retrieved materials were collected, fixed in formalin and processed for paraffin embedding, sectioned and stained with hematoxylin and eosin （HE）. The retrieved materials were microscopically divided into erythrocyte-rich thrombi, platelet/fibrin-rich thrombi, combined thrombi （similar proportions of erythrocytes and platelet/fibrin components ）, atherosclerotic plaque materials and edematous components. Based on pathological findings, thrombus materials were classified into fresh （ 〈 1 d）, lytic （1-5 d）, fresh/lytic and organized thrombi（ 〉 5 d） after formation. All patients were further classified into plaque positive and plaque negative groups. Clinical and angiographic data were also obtained for analyzing possible association between pathological findings and surrogates of myocardial reperfusion, including myocardial blush grade （MBG）, enzymatic estimated infarction size （ peak CK and CK-MB levels）, left ventricular end diastolic diameter （LVEDD） and left ventricular ejection fraction （LVEF） which were assessed 16 h after procedure. Results Visible samples were collected from 49 patients by manual catheter aspiration （thrombus components in 46 patients, atherosclerotic plaque only in 3 patients ） . Frequency of erythrocyte-rich thrombi, platelet/fibrin-rich thrombi and combined thrombi were 41.3% （ 19/46）, 30. 4% （14/46） and 28.2% （ 13/46）, respectively. The incidence of fresh, lytic, fresh/lytic and organized thrombi were 47. 8% （22/46）, 32.6% （15/46）, 10. 9% （5/46） and 8.7% （4/46）, respectively. Plaque materials were found in 57. 1% （28/49） patients, including ruptured plaque accompanied by thrombus formation [ 8.2% （4/49） ], fibrous plaque [ 6. 1% （3/ 49） ] and thickened intima [2. 0% （1/49） ]. Baseline characteristics did not differ between plaque positive （ n = 28） and plaque negative （ n = 21 ） groups. Ratios of MBG 3 were higher in plaque positive group than in plaque negative group [ 82. 1% （23/28） vs. 52. 4% （ 11/21 ） ,P = 0. 025 ]. Peak CK and CK-MB levels were lower in the former than in the later [ （ 1705 ± 1647 ） U/L vs. （2629 ± 2013 ） U/L, P = 0. 042 ; （ 146 ± 136） μg/L vs. （ 258 ± 215 ）μg/L, P = 0. 016 ; respectively]. Furthermore, LVEF were higher in plaque positive group than in plaque negative group （0. 59 ± 0. 10 vs. 0. 52 ± 0. 08, P = 0. 012）. Conclusion Manual catheter aspiration during primary PCI in STEMI patients is an effective way for removing thrombus and plaque materials, and plaque debulking before stenting or pre-dilation and this procedure might probably improve myocardial reperfusion, limit infarction size and improve cardiac function.