Cardiac Cryoablation Catheter

描述（由申请人提供）：心房颤动（AF）是临床实践中最常见的心律失常，也是最常见的需要住院的心律失常。美国有近300万人患有心房纤颤。40岁以上的美国人一生中有四分之一的人有患心房颤动的风险。目前只有一种实用的治疗方法，即肺静脉隔离（PVI）与射频消融导管。在300万房颤患者中，每年只有约3000人（0.1%）通过这种复杂而危险的手术得到治疗和治愈。射频消融产生高热损伤，不可避免地涉及一定程度的组织破坏，增加穿孔和中风的风险。相反，通过冷冻对组织的破坏导致最小的组织破坏，并保留基本的底层组织结构。冷冻消融治疗因其固有的安全性而具有吸引力，然而由于技术缺陷，通过导管冷冻消融的前景尚未完全实现。目前使用的心脏冷冻消融导管存在冷却能力不足的问题。瓶颈是可以通过狭窄的导管排出的蒸气量（就像通过吸管呼吸一样）。因此，冷冻消融的成功率降低了，尽管射频消融有缺点，但由于必要性，射频消融仍然是治疗的选择。我们提出了一种方法，以显着提高冷却能力的心脏冷冻消融导管通过消除需要排气蒸汽。相反，蒸汽将在封闭循环微型冷冻制冷系统中再循环。我们的目标是压缩、浓缩和再利用导管内的蒸汽。先进制冷技术公司（ART）提出通过两项创新技术来实现这些目标：1)ART的激光驱动压缩机技术和2)ART的微通道热交换器技术。由此产生的液化器（压缩机+冷凝器）将消除一起排出蒸汽的需要。在第一阶段，将处理以下三个具体目标：我们的激光压缩机技术将蒸汽加压到液化压力的可行性。2. 我们的热交换器技术的可行性，有效地冷却，冷凝和液化蒸汽。3. 冷冻消融在活体心脏组织上的演示。在后续工作中，该装置将被植入心脏冷冻消融球囊导管中。通过为主流心电专家提供一种治疗公众的安全工具，更强的低温将影响公众健康。公共卫生相关性：美国有300万人患有心房颤动。40岁以上的美国人一生中有四分之一患心房颤动的风险。目前，每年只有3000例（0.1%）患者接受这种复杂、有风险且无法广泛应用的治疗。这个项目将帮助开发一种设备，为医生提供一种更安全、更简单、成本更低的治疗方法，为更多患有这种衰弱疾病的人提供服务。

DESCRIPTION (provided by applicant): Atrial fibrillation (AF) is the most frequent arrhythmia encountered in clinical practice and is the most common arrhythmia necessitating hospital admission. Nearly three million people in the U.S. have Atrial Fibrillation. Americans over 40 have a one in four lifetime risk of developing Atrial Fibrillation. Currently there is only one practical treatment, pulmonary vein isolation (PVI) with a radiofrequency (RF) ablation catheter. Of the 3 million people suffering from Atrial Fibrillation, only about 3,000 (0.1%) annually are treated and cured with this complex and risky procedure. RF ablation creates hyperthermia lesions and inevitably involves some degree of tissue disruption that increases the risk for perforation and stroke. In contrast, the destruction of tissue by freezing results in minimal tissue disruption and preserves basic underlying tissue architecture. Treatment using cryoablation is attractive because of its inherent safety, however the promise of cryoablation via catheterization has not yet been fully realized because of technical shortcomings. Currently used cardiac cryoablation catheters suffer from lack of cooling power. The bottleneck is in the amount of vapor that can be exhausted through the narrow catheter (like breathing through a straw). As a result, the success of cryoablation is reduced and, by necessity, radio frequency ablation has remained the treatment of choice despite its shortcomings. We propose a method to dramatically increase the cooling power of cardiac cryoablation catheters by eliminating the need to exhaust the vapor. Instead, the vapor will be re-circulated in a closed cycle miniature cryo refrigeration system. Our goal is to compress, condense and re-use the vapor inside the catheter. Advanced Refrigeration Technologies (ART) proposes to achieve these aims with two innovative technologies: 1) ART's laser-powered compressor technology and 2) ART's microchannel heat exchanger technology. The resulting liquefier (compressor+condenser) will eliminate the need to exhaust the vapor all together. During Phase I the following three specific aims will be addressed: 1. Feasibility of our laser-powered compressor technology to pressurize vapor to liquefaction pressure. 2. Feasibility of our heat exchanger technology to effectively cool, condensate and liquefy the vapor. 3. Demonstration of cryoablation on live heart tissue. In subsequent work, the device will be implanted in a cardiac cryoablation balloon catheter. Stronger cryo will impact public health by providing to the mainstream electrocardiologists a safe tool to treat the general public. PUBLIC HEALTH RELEVANCE: Three million people in the U.S. suffer from Atrial Fibrillation. Americans over 40 years old have a one in four risk of developing Atrial Fibrillation in their lifetime. Currently, only 3,000 (0.1%) annually are treated with a procedure that is complex, risky and not widely available. This project will help develop a device that will provide doctors a safer, simpler and lower cost procedure that will serve larger numbers of people suffering from this debilitating condition.