Subvalvular Aortic Stenosis: Current Insights into an Often Overlooked Cause of Left Ventricular Outflow Tract (LVOT) Obstruction

Background: Subvalvular aortic stenosis (SAS) is an important cause of fixed left ventricular outflow tract obstruction and the second most common form of aortic stenosis. Although traditionally considered a congenital lesion, increasing evidence suggests that SAS often behaves as a progressive condition influenced by anatomical and hemodynamic factors. The disease may lead to significant complications, including left ventricular hypertrophy and progressive aortic regurgitation. Materials and Methods: A narrative review of the current literature was performed to summarize contemporary knowledge regarding the epidemiology, pathophysiology, clinical presentation, diagnostic evaluation, and management of subvalvular aortic stenosis. Relevant studies were identified through searches of major medical databases and were critically analyzed to provide an overview of current concepts and clinical practice. Results: Subvalvular aortic stenosis demonstrates considerable anatomical and clinical heterogeneity, ranging from discrete subaortic membranes to fibromuscular tunnel-type obstruction. The condition often progresses over time, with increasing LVOT gradients and a high incidence of associated aortic regurgitation. Echocardiography remains the primary diagnostic modality, while advanced imaging techniques provide additional anatomical detail and assist in surgical planning. Surgical resection remains the cornerstone of treatment when significant obstruction or related complications develop. Conclusions: Subvalvular aortic stenosis is a complex and progressive disease requiring careful imaging assessment and timely surgical management. Although surgical outcomes are generally excellent, recurrence and progressive aortic valve involvement remain important long-term considerations. Ongoing research aimed at improving risk stratification and optimizing surgical strategies may further enhance patient outcomes.