High-Intensity Ultrasound Ablation for Septal Reduction Therapy of Hypertrophic Cardiomyopathy

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PROJECT SUMMARY Obstructive hypertrophic cardiomyopathy (HCM) causes significant symptoms and morbidity due to left ventricular outflow tract obstruction (LVOTO). Interventricular septal (IVS) reduction procedures for LVOTO such as alcohol septal ablation and surgical myectomy relieve symptoms and reduce sudden death risk, but are often initiated late in the disease process due to their peri-operative risk, anatomic constrains, complications (particularly atrio-ventricular (AV) block) and limited efficacy. Our laboratory has developed an attractive approach to IVS reduction therapy (SRT) and obtained preliminary large animal data using a high- intensity ultrasound (HIU) catheter system for the treatment of oHCM, severe LVOTO and its consequences. HIU has distinct benefits over existing SRT methods in that it: 1) is less invasive (delivered via a femoral venous approach to the right ventricle (RV)). 2) selectively ablates the mid-myocardium while sparing the sub-endocardium (which contains the His- Purkinje system), thereby reducing risk of AV block. 3) does not rely on unpredictable anatomic availability of septal perforator coronary artery branches. This proposal will further develop HIU IVS reduction by optimizing lesion size and depth, avoiding the near-field subendocardium, tracking catheter location/orientation/contact, confirming effective formation non- invasively, and initiating regulatory work to position us for first-in-human studies with a subsequent award. In Aim 1, we will use acoustic simulations to design, fabricate and validate optimal HIU transducers and catheters in ex-vivo models. Aim 2 will develop and test several advanced catheter design features that will confirm transducer-tissue contact, track catheter location in real time, and confirm effective IVS ablation after HIU sonication is performed. Aim 3 will study fully-developed HIU catheters in-vivo to determine ability to reduce IVS thickness (and local myocardial mechanics) over 30 day survival. The assembled team includes exerts in therapeutic ultrasound, acoustic physics, echocardiography, cardiac MRI, large animal research methods, research sonographer, and an HCM clinical researcher who will help with eventual translation of this work to first-in-man studies. Regulatory consultants will ensure that animal studies are performed in a Good Labor and Practices (GLP)-compliant manner, positioning our group for an Investigational Device Exemption for an Early Feasibility Study with subsequent awards.