Destruction of contrast microbubbles by ultrasound - Effects on myocardial function, coronary perfusion pressure, and microvascular integrity
Destruction of contrast microbubbles by ultrasound - Effects on myocardial function, coronary perfusion pressure, and microvascular integrity
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DOI：
10.1161/hc3001.092038
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发表时间：
2001-07-24
期刊：
影响因子：
37.8
通讯作者：
Vanoverschelde, JLJ
中科院分区：
文献类型：
--
作者：
Ay, T;Havaux, X;Vanoverschelde, JLJ
背景-最近的实验数据表明，超声引起的超声造影剂微泡的破坏可导致这些微泡所在的微血管立即破裂。用含有超声造影剂的缓冲液逆行灌注离体兔心，宽带换能器以1.8 MHz发射，以3.6 MHz接收，并以触发模式（1 Hz）工作。在每次实验结束时，将心脏固定在戊二醛中，并用光学显微镜检查。无论是暴露于超声单独或造影剂单独影响左心室发展的压力。相比之下，同时暴露于造影剂和超声导致左心室发展压力的可逆的、短暂的机械指数（MI）依赖性降低（MI为1.6时为基线的83 +/-5%）和冠状动脉灌注压的短暂MI依赖性增加（MI为1.6时为基线的120 +/-6%）。随着MI的增加，心肌乳酸释放也显著增加。肉眼观察，在暴露于造影剂和高MI超声的心脏中，在波束升高上识别出壁内出血区域。光学显微镜检查显示毛细血管破裂、红细胞外渗和内皮细胞损伤。在MI为1.6时毛细血管破裂的平均百分比为3.6 +/-1.4%.Conclusions-同时暴露于离体兔心脏超声和造影剂导致MI依赖性的、短暂的左心室收缩功能抑制、冠状动脉灌注压升高、乳酸产生增加和有限的毛细血管破裂。
Background-Recent experimental data indicate that ultrasound-induced destruction of ultrasound contrast microbubbles can cause immediate rupture of the microvessels in which these microbubbles are located.Methods and Results-To examine the functional and morphological significance of these findings in the heart, isolated rabbit hearts were perfused retrogradely with buffer containing ultrasound contrast agents and were insonated at increasing levels of acoustic energy with a broadband transducer emitting at 1.8 MHz and receiving at 3.6 MHz and operated in the triggered mode (I Hz). At the end of each experiment, the hearts were fixed in glutaraldehyde and examined with light microscopy. Neither exposure to ultrasound alone or to contrast alone affected left ventricular developed pressure. By contrast, simultaneous exposure to contrast and ultrasound resulted in a reversible, transient mechanical index (Ml)-dependent decrease in left ventricular developed pressure (to 83 +/-5% of baseline at an MI of 1.6) and a transient MI-dependent increase in coronary perfusion pressure (to 120 +/-6% of baseline at an MI of 1.6). Myocardial lactate release also showed significant increases with increasing MIs. Macroscopically, areas of intramural hemorrhage were identified over the beam elevation in hearts exposed to both contrast and high-MI ultrasound. Light microscopy revealed the presence of capillary ruptures, erythrocyte extravasation, and endothelial cell damage. The mean percentage of capillaries ruptured at an MI of 1.6 was 3.6 +/-1.4%.Conclusions-Simultaneous exposure of isolated rabbit hearts to ultrasound and contrast agents results in an MI-dependent, transient depression of left ventricular contractile function, a rise in coronary perfusion pressure, an increase in lactate production, and limited capillary ruptures.