Ultrasound Guided Mitral Valve Ablation

 描述（由申请人提供）：心脏瓣膜疾病是心血管疾病的第三大最常见来源，仅在美国每年就导致约20，000例死亡。此外，在美国每年估计有95，000例瓣膜手术，其中43%为二尖瓣（MV）手术。在未来数年，由于本港人口的寿命继续延长，这些数字将会大幅增加。在接下来的50年里，美国65岁以上的人口将增加一倍以上，从3400万增加到7900万。事实上，老年人中的最老者（85岁以上）目前是人口中增长最快的部分，到2050年将翻两番。鉴于已知的心脏瓣膜疾病，特别是二尖瓣疾病，这些数字令人震惊。目前，导致二尖瓣返流（MR）的二尖瓣脱垂长期治疗的“金标准”是开胸修复或置换手术，这对老年患者来说是非常不可取的。MMVD患者的经皮治疗作为开胸手术的替代方案具有强烈的临床需求。本提案的目的是为集成导管开发一种成像策略，以减小增大的粘液瘤性MV瓣叶的尺寸，为开胸手术瓣叶切除术提供经皮替代方案。这种集成导管的新奇在于，它同时使用冷冻锚定， 粘附在运动的MV瓣叶上，同时用射频（RF）能量消融，以改变瓣叶组织的尺寸和内在生物力学特性。该提案的主要进步将是成功引导导管并通过体内超声成像量化MV几何形状和血流动力学的实时变化。首先，我们将开发成像策略，以量化猪模型中MV瓣叶几何形状和血流动力学功能的变化（目的1）。然后，我们将在犬模型中证明该策略治疗导致MR的粘液瘤性MV瓣叶的能力（目的2）。本研究的终点将是证明图像引导的射频能量输送，并确认粘液瘤二尖瓣瓣叶经皮治疗的MR减少。此外，每个目标的成功完成将使该策略转化为临床。

 DESCRIPTION (provided by applicant): Heart valve disease is the 3rd most prevalent source of cardiovascular disease, leading to ~20,000 deaths per year in the U.S. alone. Moreover, there are an estimated 95,000 valve procedures performed each year in the U.S. and 43% of these are mitral valve (MV) procedures. These numbers will increase substantially in the coming years as our population continues to live longer. Over the next 50 years, the population of Americans age 65+ will more than double - from 34 to 79 million. In fact, the oldest of the old (85+) are currently the fastest growing segment of the population and will more than quadruple by 2050. These numbers are alarming in light of what is known of heart valve disease, particularly in the MV. Today, the 'gold standard' for long-term treatment for MV prolapse, leading to mitral regurgitation (MR), is open-chest repair or replacement surgery, which is highly undesirable for elderly patients. There is a strong clinical need for percutaneous treatment for patients with MMVD as an alternative to open-chest surgery. The goal of this proposal is to develop an imaging strategy for an integrated catheter to reduce the size of enlarged, myxomatous MV leaflets, providing a percutaneous alternative to open-chest surgical leaflet resection. The novelty of this integrated catheter is that it simultaneously uses cryo-anchoring to adhere to a moving MV leaflet, while ablating with radiofrequency (RF) energy to alter the size and intrinsic biomechanical properties of the leaflet tissue. The primary advancements of this proposal will be to successfully guide the catheter and quantify real-time changes of MV geometry and hemodynamics with ultrasound imaging in vivo. First, we will develop the imaging strategy to quantify changes to MV leaflet geometry and hemodynamic function in a swine model (Aim 1). Then, we will demonstrate this strategy's ability to treat myxomatous MV leaflets that lead to MR in a canine model (Aim 2). The endpoint of this research will be demonstration of image-guided delivery of RF energy and validation of reduced MR for the percutaneous treatment of myxomatous MV leaflets. Further, successful completion of each aim will position this strategy for translation into the clinic.