Mizuno K, Satomura K, Miyamoto A, Arakawa K, Shibuya T, Arai T, Kurita A, Nakamura H, Ambrose J A
First Department of Internal Medicine, National Defense Medical College, Saitama, Japan.
N Engl J Med. 1992 Jan 30;326(5):287-91. doi: 10.1056/NEJM199201303260502.
Disruption of an atherosclerotic plaque in a coronary artery followed by the formation of a thrombus is believed to be the cause of both unstable angina and acute myocardial infarction. Although thrombolytic therapy is efficacious in patients with acute myocardial infarction, for unknown reasons it is far less effective in patients with unstable angina. We postulated that there might be differences in the composition of the coronary-artery thrombi in unstable angina and acute myocardial infarction.
To investigate the appearance of coronary-artery thrombi, we performed percutaneous transluminal coronary angioscopy in 15 patients with unstable angina and 16 with acute myocardial infarction. Angioscopy was performed within 48 hours after an episode of pain at rest in the patients with unstable angina and within 8 hours of onset in those with acute myocardial infarction.
Angioscopy revealed coronary thrombi in all but two patients (one in each group). Of the 29 patients with thrombi, those with unstable angina were frequently observed to have grayish-white thrombi (10 of 14, 71 percent), but none were seen in the 15 patients with acute myocardial infarction (P less than 0.01). By contrast, reddish thrombi were observed in all 15 patients with acute myocardial infarction who had thrombi, but in only 4 of the 14 patients with unstable angina and thrombi (P less than 0.01). As assessed by coronary angiography, occlusive thrombi occurred frequently in patients with acute myocardial infarction (13 of 16 patients) but were not seen in any of the 15 patients with unstable angina (P less than 0.01).
Coronary-artery thrombi play an important part in the pathogenesis of unstable angina and acute myocardial infarction. However, the appearance of the thrombi is different in the two conditions, possibly reflecting differences in the composition of age of the thrombi or the presence or absence of blood flow in the artery. This difference may account for the contrasting results of thrombolytic therapy.
冠状动脉粥样硬化斑块破裂后形成血栓被认为是不稳定型心绞痛和急性心肌梗死的病因。尽管溶栓治疗对急性心肌梗死患者有效，但不知为何，其对不稳定型心绞痛患者的疗效要差得多。我们推测，不稳定型心绞痛和急性心肌梗死患者冠状动脉血栓的成分可能存在差异。
为研究冠状动脉血栓的外观，我们对15例不稳定型心绞痛患者和16例急性心肌梗死患者进行了经皮腔内冠状动脉血管镜检查。不稳定型心绞痛患者在静息痛发作后48小时内进行血管镜检查，急性心肌梗死患者在发病后8小时内进行检查。
血管镜检查发现，除2例患者（每组各1例）外，其余患者均有冠状动脉血栓。在29例有血栓的患者中，不稳定型心绞痛患者常可见灰白色血栓（14例中的10例，71%），而15例急性心肌梗死患者中均未见到（P<0.01）。相比之下，15例有血栓的急性心肌梗死患者均可见红色血栓，而14例有血栓的不稳定型心绞痛患者中仅4例可见（P<0.01）。冠状动脉造影显示，急性心肌梗死患者中闭塞性血栓常见（16例患者中的13例），而15例不稳定型心绞痛患者中均未见到（P<0.01）。
冠状动脉血栓在不稳定型心绞痛和急性心肌梗死的发病机制中起重要作用。然而，两种情况下血栓的外观不同，这可能反映了血栓成分、血栓形成时间或动脉血流情况的差异。这种差异可能解释了溶栓治疗结果的不同。
