Chareonthaitawee P, Christian T F, Hirose K, Gibbons R J, Rumberger J A
Division of Cardiovascular Disease and Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905.
J Am Coll Cardiol. 1995 Mar 1;25(3):567-73. doi: 10.1016/0735-1097(94)00431-O.
This study attempted to determine the relation between infarct size after acute myocardial infarction and subsequent left ventricular remodeling using precise clinical measurements.
Animal studies have demonstrated that the degree of left ventricular remodeling after myocardial infarction is linearly related to infarct size. Clinical studies have not clearly replicated these results because of imprecise measurements and failure to adjust for patency of the infarct-related artery.
Infarct size was measured from technetium-99m (Tc-99m) sestamibi perfusion images in 14 patients (12 with an anterior, 2 with an inferior infarction) by a threshold method previously described and expressed as percent of the left ventricle (32 +/- 17% left ventricle [mean +/- SD], range 6% to 58%). Absolute end-systolic volume, end-diastolic volume and ejection fraction were determined by electron beam computed tomographic images performed at discharge and at 6 weeks, 6 months and 1 year after myocardial infarction. All patients had documented infarct-related artery patency after reperfusion therapy.
At hospital discharge, there was no correlation between infarct size and end-systolic and end-diastolic volumes or ejection fraction. There was significant left ventricular dilation in the study group over the next year. As remodeling progressed, there was closer correlation between infarct size and ejection fraction and end-systolic volume measures (infarct size vs. end-systolic volume, from r = 0.43 at discharge to r = 0.80 at 1 year; infarct size vs. ejection fraction, from r = -0.39 at discharge to r = -0.84 at 1 year). There was a strong inverse correlation between infarct size at discharge and subsequent changes over the next year in end-systolic volume (r = 0.63, p = 0.02) and ejection fraction (r = -0.66, p = 0.01).
Infarct size as measured by Tc-99m sestamibi at hospital discharge after an index infarction is predictive of subsequent change in left ventricular volume and function in the year after myocardial infarction. Patients with a large infarct demonstrated the greatest degree of dilation in the setting of patency of the infarct-related artery.
本研究试图通过精确的临床测量来确定急性心肌梗死后梗死面积与随后左心室重构之间的关系。
动物研究表明，心肌梗死后左心室重构的程度与梗死面积呈线性相关。由于测量不精确以及未对梗死相关动脉的通畅情况进行校正，临床研究尚未明确重现这些结果。
采用先前描述的阈值法，从14例患者（12例前壁梗死，2例下壁梗死）的锝-99m（Tc-99m） sestamibi灌注图像中测量梗死面积，并表示为左心室的百分比（左心室的32±17%[平均值±标准差]，范围为6%至58%）。通过在心肌梗死后出院时以及6周、6个月和1年时进行的电子束计算机断层扫描图像确定绝对收缩末期容积、舒张末期容积和射血分数。所有患者在再灌注治疗后梗死相关动脉均通畅。
出院时，梗死面积与收缩末期和舒张末期容积或射血分数之间无相关性。在接下来的一年中，研究组出现了显著的左心室扩张。随着重构的进展，梗死面积与射血分数和收缩末期容积测量值之间的相关性更紧密（梗死面积与收缩末期容积，出院时r = 0.43，1年时r = 0.80；梗死面积与射血分数，出院时r = -0.39，1年时r = -0.84）。出院时的梗死面积与接下来一年中收缩末期容积（r = 0.63，p = 0.02）和射血分数（r = -0.66，p = 0.01）的后续变化之间存在强烈的负相关。
首次梗死后出院时通过Tc-99m sestamibi测量的梗死面积可预测心肌梗死后一年中左心室容积和功能的后续变化。在梗死相关动脉通畅的情况下，梗死面积大的患者扩张程度最大。
