Reverse remodeling after percutaneous transluminal septal myocardial ablation in severe but asymptomatic LVOT obstruction (RASTA) study: Rationale and design of transcatheter septal reduction in asymptomatic patients with severe hypertrophic obstructive cardiomyopathy

Objectives: The aim of this study is to evaluate the impact of percutaneous transluminal septal myocardial ablation (PTSMA) on remodeling in asymptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM) and severe left ventricular outflow tract (LVOT) obstruction.

Background: Symptoms justify invasive treatment in HOCM patients with LVOT obstruction. Adverse structural and functional changes (remodeling) in the heart occur preceding heart failure and sudden cardiac death. Early invasive treatment in asymptomatic patients may reverse adverse remodeling to the same extent as in symptomatic patients.

Methods: Reverse remodeling after PTSMA in severe but asymptomatic LVOT obstruction (RASTA) study is a prospective single-blind randomized trial (ClinicalTrials.gov number: NCT04230551). Ten asymptomatic HOCM patients with an exertional LVOT gradient ≥50 mmHg (or >30 mmHg in rest) are randomized 1:1 to PTSMA versus conservative therapy, in the absence of mitral valve disease or other indications for cardiac surgery. Five symptomatic (reference group) will undergo PTSMA according to the current guidelines.

Results: Remodeling is assessed using extensive cardiac imaging with transthoracic echocardiography and late gadolinium enhancement cardiac magnetic resonance at baseline and during follow-up at 1, 12, and 24 months. Extracellular volume fraction, global, and regional strain analysis, geometry, pressure gradients and changes in four-dimensional velocity mapping are primary parameters to study (reversal of) adverse remodeling.

Conclusions: The RASTA study gives insight in cardiac remodeling that may occur in asymptomatic patients after PTSMA. It will provide arguments whether to pursue (or not) a larger trial with clinical endpoints in asymptomatic HOCM patients with severe LVOT obstruction.