Subaortic membrane in adult patients: retrospective study of clinical characteristics, outcomes, and echocardiographic associations and review of literature

Abstract

This study aims to describe the clinical characteristics, outcomes, and echocardiographic associations of subaortic membranes in adult patients, providing insight into their multifactorial etiology and implications for management. The retrospective study involved identifying patients who underwent Transthoracic Echocardiography (TTE) in the past 10 years from June 2013 to June 2023 due to clinical suspicion of a subaortic membrane and received a confirmed diagnosis of subaortic membrane, either through TTE alone or a subsequent Transesophageal Echocardiogram (TEE). The demographics of the patients, including age at diagnosis, sex, and medical comorbidities such as aortic or mitral valve disease, hypertension, history of arrhythmias, coronary artery disease, heart failure, diabetes mellitus, and chronic kidney disease, were included. Features on TTE were documented. Any subsequent surgical interventions were recorded, specifically subaortic membrane resection and valve repair. A total of 22 cases were studied. The mean age of the cohort was 58.1 ± 10.6 years. Common comorbidities included hypertension (63.6%), obesity (45.4%), and heart failure (31.8%). Quantitatively, the left ventricular (LV) ejection fraction varied from normal (59-76.4%) to moderately decreased (43.8%), with a mean ejection fraction of 65.9 ± 8.0%. Diastolic dysfunction was present in various grades. Six patients had one ICU hospitalization (27.3%), and one patient had more than one ICU hospitalization (4.5%). Most had a subaortic membrane (90.9%) visualized on TTE. Two patients had possible findings suggestive of a subaortic membrane, which was confirmed on TEE (2/22; 9.1%). While most patients had a relatively benign course, three patients (13.6%) had undergone surgical interventions. The majority of the patients survived (17/22; 77.3%). Subaortic membrane is a rare condition with limited incidence, prevalence, and management data. Further large-scale studies are necessary to investigate and compile data to establish guidelines for treatment.

Keywords: Comorbidities; Outcomes; Subaortic membrane; Valvular heart disease.