Hillenbrand H B, Kim R J, Parker M A, Fieno D S, Judd R M
Northwestern University Medical School Feinberg Cardiovascular Research Institute, Chicago, IL 60611-3008, USA.
Circulation. 2000 Oct 3;102(14):1678-83. doi: 10.1161/01.cir.102.14.1678.
Myocardial salvage after acute myocardial infarction is defined clinically by early restoration of flow and long-term improvement in contractile function. We hypothesized that contrast-enhanced magnetic resonance imaging (MRI), performed early after myocardial infarction, indexes myocardial salvage. We studied the relationship between the transmural extent of hyperenhancement by contrast-enhanced MRI, restoration of flow, and recovery of function.
The left anterior descending coronary artery was occluded in dogs (n=15) for either 45 minutes, 90 minutes, or permanently. Cine and contrast-enhanced MRI were performed 3 days after the procedure; cine MRI was also done 10 and 28 days after the procedure. The transmural extent of hyperenhancement and wall thickening were determined using a 60-segment model. The mean transmural extent of hyperenhancement for the 45-minute occlusion group was 22% of the 90-minute group and 18% of the permanent occlusion group (P:<0.05 for both). The transmural extent of hyperenhancement on day 3 was related to future improvement in both wall thickening score and absolute wall thickening at 10 and 28 days (P:<0.0001 for each). For example, of the 415 segments on day 3 that were dysfunctional and had <25% transmural hyperenhancement, 362 (87%) improved by day 28. Conversely, no segments (0 of 9) with 100% hyperenhancement improved. The transmural extent of hyperenhancement on day 3 was a better predictor of improvement in contractile function than occlusion time (P:<0.0001).
A reduction in the transmural extent of hyperenhancement by contrast-enhanced MRI early after myocardial infarction is associated with an early restoration of flow and future improvement in contractile function.
急性心肌梗死后的心肌挽救在临床上定义为血流的早期恢复和收缩功能的长期改善。我们假设，在心肌梗死后早期进行的对比增强磁共振成像（MRI）可作为心肌挽救的指标。我们研究了对比增强MRI显示的心肌强化透壁范围、血流恢复和功能恢复之间的关系。
对15只犬的左前降支冠状动脉进行45分钟、90分钟或永久性闭塞。术后3天进行电影和对比增强MRI检查；术后10天和28天也进行电影MRI检查。使用60节段模型确定心肌强化的透壁范围和室壁增厚情况。45分钟闭塞组的心肌强化平均透壁范围为90分钟闭塞组的22%，永久性闭塞组的18%（两者P均<0.05）。第3天的心肌强化透壁范围与第10天和28天的室壁增厚评分及绝对室壁增厚的未来改善均相关（每项P<0.0001）。例如，在第3天功能失调且心肌强化透壁<25%的415节段中，到第28天有362节段（87%）得到改善。相反，心肌强化100%的节段无一改善（9节段中0节段）。第3天的心肌强化透壁范围比闭塞时间更能预测收缩功能的改善（P<0.0001）。
心肌梗死后早期对比增强MRI显示的心肌强化透壁范围减小与血流的早期恢复及收缩功能的未来改善相关。
