Lu Xiaofang, Miller Douglas L, Dou Chunyan, Zhu Yiying I, Fabiilli Mario L, Owens Gabe E, Kripfgans Oliver D
University of Michigan Health System, Ann Arbor, Michigan, USA.
University of Michigan Health System, Ann Arbor, Michigan, USA.
Ultrasound Med Biol. 2016 Jul;42(7):1541-50. doi: 10.1016/j.ultrasmedbio.2016.02.006. Epub 2016 Apr 14.
Myocardial contrast echocardiography at enhanced therapeutic parameters may be a novel means of tissue reduction therapy, as for hypertrophic cardiomyopathy. Dahl/SS rats were anesthetized and treated with high-amplitude pulsed ultrasound guided by 10-MHz ultrasound images. Contrast microbubbles were infused via the tail vein during intermittent pulse-burst exposure at 4 MPa. A sham group, a low-impact group (group A, 5 cycle pulses with Gaussian modulation and 1:4 trigger for 5 min) and a high-impact group (group B, 10 cycle pulses with 4-ms square modulation and 1:8 trigger for 10 min) were tested. The higher exposure used in group B yielded more substantial injury than the lower exposure in group A. Treated rats in both groups A and B had significant increases in wall thickness measured by echocardiography the next day, which returned to normal by the end of 6 wk. Six weeks after ultrasound exposure, heart tissue samples exhibited tissue fibrosis in Masson's trichrome stained histology. Maturation of lesions involved fibrosis replacement, preserving structural tissue integrity. This study indicates that myocardial injury noted previously progresses into permanent loss of myocardial tissue that may be sufficient for possible hypertrophic cardiomyopathy therapy. More research is needed to define the treatment parameters required for symptomatic relief for hypertrophic cardiomyopathy.
对于肥厚型心肌病，在增强治疗参数下的心肌对比超声心动图可能是一种新型的组织消减治疗方法。将 Dahl/SS 大鼠麻醉，在 10 兆赫兹超声图像引导下用高振幅脉冲超声进行治疗。在 4 兆帕的间歇脉冲群暴露期间，通过尾静脉注入造影微泡。测试了假手术组、低强度组（A 组，5 个周期脉冲，高斯调制，1:4 触发，持续 5 分钟）和高强度组（B 组，10 个周期脉冲，4 毫秒方波调制，1:8 触发，持续 10 分钟）。B 组使用的较高暴露比 A 组的较低暴露造成了更严重的损伤。A 组和 B 组的治疗大鼠在第二天通过超声心动图测量的壁厚均显著增加，到 6 周结束时恢复正常。超声暴露 6 周后，心脏组织样本在 Masson 三色染色组织学中显示出组织纤维化。病变的成熟涉及纤维化替代，保持组织结构完整性。本研究表明，先前观察到的心肌损伤进展为心肌组织的永久性丧失，这可能足以用于可能的肥厚型心肌病治疗。需要更多研究来确定肥厚型心肌病症状缓解所需的治疗参数。
