Safety and Efficacy of Stereotactic Body Radiotherapy in the Treatment of Hypertrophic Obstructive Cardiomyopathy

Summary

This study is designed to rigorously evaluate the safety and effectiveness of Stereotactic Body Radiotherapy (SBRT) as an innovative, non-invasive treatment for Hypertrophic Obstructive Cardiomyopathy (HOCM). HOCM, a prevalent cardiac condition, is primarily characterized by asymmetric septal hypertrophy, which results in the obstruction of the left ventricular outflow tract. This obstruction significantly compromises patient quality of life and is associated with severe risks, including arrhythmias and sudden cardiac death. While current treatments like medications, surgical septal myectomy, and percutaneous transluminal septal myocardial ablation (PTSMA) have proven to be effective, they are not without limitations. SBRT, a recent development in non-invasive cardiac radioablation, has shown encouraging results in early-stage studies, suggesting its potential as a safe and feasible option for HOCM treatment.

In this study, participants will be randomly assigned to either the SBRT treatment group or a control group receiving a sham procedure. The primary objective is to measure the change in the left ventricular outflow tract pressure gradient under provoked conditions, using cardiac ultrasound at a 6-month follow-up. This will provide a clear assessment of the direct impact of SBRT on the primary physiological complication of HOCM.

The study also sets forth several secondary objectives to provide a holistic view of the treatment's impact. These include evaluating changes in NYHA functional classification and KCCQ scores to assess improvements in symptom severity and quality of life, respectively. Additionally, we will monitor physical capacity through the 6-minute walk test, and biomarkers like NT-proBNP and cTNT for cardiac stress and damage. The effect of SBRT on QRS duration will be analyzed to understand its impact on cardiac electrical activity. The incidence of major adverse cardiac events (MACEs) within 6 months post-treatment will be recorded to evaluate safety, and the need for invasive septal reduction therapy post-treatment will be assessed to gauge long-term efficacy.

This study aims to provide a comprehensive understanding of the potential of SBRT as a treatment alternative for HOCM. By comparing its outcomes with those of traditional therapies, the study seeks to establish SBRT's role in symptom alleviation, quality of life enhancement, and risk reduction in HOCM management.

Conditions

• Hypertrophic Obstructive Cardiomyopathy
• Stereotactic Body Radiotherapy

Interventions

RADIATION

Stereotactic Body Radiotherapy (SBRT) Treatment

The intervention in this study utilizes Stereotactic Body Radiotherapy (SBRT) for treating Hypertrophic Obstructive Cardiomyopathy (HOCM). The process begins with precise localization and planning, employing CT scans, Cardiac MRI (CMR), and echocardiography to accurately identify the target area in the interventricular septum, while avoiding critical structures like the aortic valve, His bundle, and left ventricular papillary muscles. Pre-treatment preparation involves using customized fixation devices to limit patient movement and breathing, coupled with cone-beam CT scans for accurate alignment with the Treatment Planning System (TPS). The treatment itself is delivered using image-guided linear accelerators, administering a single, focused dose of 25 Gy to the targeted area. This approach ensures precise radiation delivery, maximizing treatment efficacy while minimizing risks to surrounding cardiac tissues.

OTHER

Sham Procedure

The sham procedure in this study is designed to closely mimic the actual Stereotactic Body Radiotherapy (SBRT) process without delivering any radiation. Participants in this arm are subjected to the same initial steps as those in the SBRT group, including precise alignment with the linear accelerator using CT scans and the application of customized fixation devices to limit movement and breathing. However, in this sham intervention, the linear accelerator is activated but does not emit any radiation. The procedure replicates the environmental aspects of the actual treatment, such as the equipment's sounds and lighting, to maintain the study's single-blind nature. This method ensures that participants in the sham group experience a procedure identical in appearance and feel to the SBRT treatment, without receiving any therapeutic dose, thereby serving as an effective control for evaluating the true impact of SBRT in treating HOCM.

Sponsors & Collaborators

• Second Xiangya Hospital of Central South University

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2023-12-15

Primary Completion

2024-12-15

Completion

2025-06-15

Countries

• China

Study Locations