Shock Wave Lithotripsy: Mechanisms and Amelioration of Vascular Damage

在目前的临床实践中，冲击波碎石术(SWL)是治疗尿路结石(肾结石)的常规方法。它还会导致急性肾脏损伤：包括出血、血肿和水肿。小血管破裂是SWL相关血管损伤的主要特征。潜在的机制是：受约束气泡的生长导致血管的伸展和破裂，或受约束的空化气泡的不对称坍塌对管壁的破坏，以及在气泡坍塌时产生的自由基的攻击可能对管壁造成的破坏。先前的工作表明，体外实验中，气泡与XL-1碎石机对幻影血管的损伤有关。然而，对于损害的确切机制还存在疑问。先前的工作也表明，为了更好地与实验相比较，需要在SWL气泡模拟中包括蒸汽动力学。对包括热和蒸汽传输在内的非球形塌陷进行了数值模拟。对Dornier HM-3临床碎石机进行轻微改进，可以减少有问题的气泡生长，从而降低SWL中血管损伤的可能性，同时保持满意的结石粉碎效果。最后，研究人员开发了球面压缩波聚焦成冲击波的分析理论和计算机模拟，即使在存在强烈的材料不均匀性的情况下也是如此。拟议的研究的第一个目标是确定血管中气泡与碎石机冲击波(LSW)相互作用的破坏机制。第二个目标是开发一种合理的程序来优化成为LSW的压缩波，以便在保持石材粉碎的同时将气泡增长的可能性降至最低。这两个目标都将通过理论、仿真和实验来实现。

0201921SzeriIn current clinical practice, Shock Wave Lithotripsy (SWL) is routinely used for treatment of urolithiasis (kidney stones). It also causes acute renal injury: including hemorrhage, hematoma and edema. The rupture of small blood vessels is a primary feature of vascular injury associated with SWL. The potential mechanisms are: stretching and rupture of vessels by growth of constrained bubbles, or damage of vessel walls by asymmetric collapse of constrained cavitation bubbles, and possibly damage of vessel walls by attack of free radicals produced in the bubble collapses. Prior work has shown that bubbles are associated with phantom vessel damage by an XL-1 lithotripter in vitro . However, there is doubt as to the precise mechanism of damage. Prior work has also shown that, to compare well with experiments, vapor dynamics need to be included in SWL bubble simulations. A simulation has been developed of non-spherical collapses including heat and vapor transfer. A slight modification to a Dornier HM-3 clinical lithotripter can reduce problematical bubble growth and thus decrease the potential for vascular injury in SWL while maintaining satisfactory stone comminution. Finally, the investigators have developed an analytical theory and computer simulation of the focusing of spherical compression waves into shocks, even where there are strong material inhomogeneities.The first goal of the proposed research is to determine the mechanism of damage by bubbles in blood vessels interacting with lithotripter shock waves (LSW). The second goal is to develop a rational procedure to optimize the compression wave that becomes the LSW, so as to minimize the potential for bubble growth while maintaining stone comminution. Both goals will be reached through theory, simulation and experiment.