Wu K C, Zerhouni E A, Judd R M, Lugo-Olivieri C H, Barouch L A, Schulman S P, Blumenthal R S, Lima J A
Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Md, USA.
Circulation. 1998 Mar 3;97(8):765-72. doi: 10.1161/01.cir.97.8.765.
The extent of microvascular obstruction during acute coronary occlusion may determine the eventual magnitude of myocardial damage and thus, patient prognosis after infarction. By contrast-enhanced MRI, regions of profound microvascular obstruction at the infarct core are hypoenhanced and correspond to greater myocardial damage acutely. We investigated whether profound microvascular obstruction after infarction predicts 2-year cardiovascular morbidity and mortality.
Forty-four patients underwent MRI 10 +/- 6 days after infarction. Microvascular obstruction was defined as hypoenhancement seen 1 to 2 minutes after contrast injection. Infarct size was assessed as percent left ventricular mass hyperenhanced 5 to 10 minutes after contrast. Patients were followed clinically for 16 +/- 5 months. Seventeen patients returned 6 months after infarction for repeat MRI. Patients with microvascular obstruction (n = 11) had more cardiovascular events than those without (45% versus 9%; P=.016). In fact, microvascular status predicted occurrence of cardiovascular complications (chi2 = 6.46, P<.01). The risk of adverse events increased with infarct extent (30%, 43%, and 71% for small [n = 10], midsized [n = 14], and large [n = 14] infarcts, P<.05). Even after infarct size was controlled for, the presence of microvascular obstruction remained a prognostic marker of postinfarction complications (chi2 = 5.17, P<.05). Among those returning for follow-up imaging, the presence of microvascular obstruction was associated with fibrous scar formation (chi2 = 10.0, P<.01) and left ventricular remodeling (P<.05).
After infarction, MRI-determined microvascular obstruction predicts more frequent cardiovascular complications. In addition, infarct size determined by MRI also relates directly to long-term prognosis in patients with acute myocardial infarction. Moreover, microvascular status remains a strong prognostic marker even after control for infarct size.
急性冠状动脉闭塞期间微血管阻塞的程度可能决定心肌损伤的最终程度，进而影响梗死患者的预后。通过对比增强磁共振成像（MRI），梗死核心处严重微血管阻塞区域表现为低增强，且与急性期更大的心肌损伤相对应。我们研究了梗死后严重微血管阻塞是否可预测2年心血管疾病的发病率和死亡率。
44例患者在梗死后10±6天接受了MRI检查。微血管阻塞定义为注射对比剂后1至2分钟出现的低增强。梗死面积通过对比剂注射后5至10分钟左心室质量高增强的百分比来评估。对患者进行了16±5个月的临床随访。17例患者在梗死后6个月返回进行重复MRI检查。有微血管阻塞的患者（n = 11）比无微血管阻塞的患者发生更多的心血管事件（45%对9%；P = 0.016）。事实上，微血管状态可预测心血管并发症的发生（χ² = 6.46，P < 0.01）。不良事件的风险随梗死范围增加（小梗死[n = 10]为30%，中等梗死[n = 14]为43%，大梗死[n = 14]为71%，P < 0.05）。即使在控制梗死面积后，微血管阻塞的存在仍然是梗死后并发症的预后标志物（χ² = 5.17，P < 0.05）。在返回进行随访成像的患者中，微血管阻塞的存在与纤维瘢痕形成（χ² = 10.0，P < 0.01）和左心室重构（P < 0.05）相关。
梗死后，MRI确定的微血管阻塞预示着更频繁的心血管并发症。此外，MRI确定的梗死面积也与急性心肌梗死患者的长期预后直接相关。而且，即使在控制梗死面积后，微血管状态仍然是一个强有力的预后标志物。
