Song J-K
Asan Medical Center Heart Institute, University of Ulsan College of Medicine, 388-1 Poongnap-dong Songpa-gu, 138-736, Seoul, South Korea.
Herz. 2011 Sep;36(6):488-97. doi: 10.1007/s00059-011-3501-0.
Non-invasive tomographic imaging modalities have recently contributed to identifying aortic intramural hematoma, a variant form of classic dissection, which is characterized by the absence of an intimal tear and thus the absence of direct flow communication, and which represents an important disease entity in acute aortic syndrome. Clinical investigations have revealed that intramural hematoma has characteristic clinical features and that the natural remodeling process of hematoma is different from that of classic aortic dissection. These findings suggest that intramural hematoma is not just a precursor to aortic dissection, but may be a unique disease entity with a more favorable prognosis compared to aortic dissection. There is regional heterogeneity regarding the relative incidence of this hematoma, with higher incidence seen in Eastern countries. Due to favorable outcomes with medical treatment in Asian patients with type A intramural hematoma, a tailored or individualized approach based on risk stratification using initial clinical information and including imaging studies and timely surgical repair has been suggested in hemodynamically stable patients; however, these results need to be confirmed in other patient populations. The concept of a "micro-tear" which cannot be easily visualized using conventional imaging modalities has been raised: "echo-free space" on transesophageal echocardiography and "focal contrast enhancement" on ultra-fast computerized tomography have drawn many physicians' attention, and the possibility of a pathophysiologic link between classic aortic dissection and intramural hematoma has been discussed. Further investigations are needed to test whether intramural hematoma begins with an initial intimal tear and a different aortic status--characterized by a more rigid and non-compliant aorta associated with old age or long-standing hypertension--and results in an apparently absent intimal flap.
非侵入性断层成像技术最近有助于识别主动脉壁内血肿，这是经典主动脉夹层的一种变异形式，其特征是没有内膜撕裂，因此没有直接的血流连通，并且它是急性主动脉综合征中的一个重要疾病实体。临床研究表明，壁内血肿具有特征性的临床特征，并且血肿的自然重塑过程与经典主动脉夹层不同。这些发现表明，壁内血肿不仅仅是主动脉夹层的前驱病变，而是可能是一种独特的疾病实体，与主动脉夹层相比预后更有利。这种血肿的相对发病率存在区域异质性，在东方国家发病率较高。由于亚洲A型壁内血肿患者内科治疗效果良好，对于血流动力学稳定的患者，建议采用基于初始临床信息（包括影像学检查）进行风险分层并适时进行手术修复的定制化或个体化方法；然而，这些结果需要在其他患者群体中得到证实。有人提出了一种使用传统成像方式不易观察到的“微撕裂”概念：经食管超声心动图上的“无回声区”和超快速计算机断层扫描上的“局灶性对比增强”引起了许多医生的关注，并且已经讨论了经典主动脉夹层与壁内血肿之间病理生理联系的可能性。需要进一步研究来检验壁内血肿是否始于初始内膜撕裂以及不同的主动脉状态——其特征是与老年或长期高血压相关的更僵硬且顺应性差的主动脉——并导致明显不存在内膜瓣。
