The Role of Perioperative Transesophageal Echocardiography in the Diagnosis and Management of Discrete Subaortic Stenosis in an Adult Patient

Introduction Discrete subaortic stenosis (DSS) is an uncommon cause of left ventricular outflow tract (LVOT) obstruction in adults and may mimic severe aortic stenosis. Perioperative transesophageal echocardiography (TEE) plays a key role in defining the anatomical level of obstruction and guiding surgical management. We report the anesthetic and echocardiographic management of an adult patient undergoing surgical correction of DSS. Methods A 53-year-old woman presented with progressive exertional dyspnea and fatigue. Electrocardiography demonstrated sinus rhythm. Transesophageal echocardiography performed at an outside institution revealed a peak LVOT gradient of 100 mmHg. Coronary angiography showed normal coronary arteries. Preoperative transthoracic echocardiography demonstrated severe LVOT obstruction with a peak gradient of 80 mmHg and a mean gradient of 48 mmHg. Left ventricular ejection fraction was 60%. The aortic valve was tricuspid without aortic regurgitation. Carotid Doppler ultrasonography was unremarkable. After placement of invasive arterial and central venous monitoring, balanced general anesthesia was induced according to institutional cardiac anesthesia protocols. Intraoperative TEE was performed before cardiopulmonary bypass and used throughout the procedure for diagnostic confirmation, surgical planning, and perioperative assessment. TEE identified a centrally mobile fibrous membrane immediately beneath the aortic valve, extending circumferentially along the aortic annulus and causing significant LVOT narrowing. The examination clarified the anatomical level and mechanism of obstruction and guided surgical planning. The patient underwent median sternotomy and cardiopulmonary bypass. Surgical exploration confirmed a discrete subendocardial fibrous membrane beneath the aortic valve. Complete membrane resection was performed. Additionally, a crescent-shaped septal myectomy measuring approximately 0.5 × 2 cm was carried out 1 cm below the right coronary commissure to enlarge the LVOT. Echocardiographic findings showed excellent correlation with intraoperative findings and the excised specimen. Total operative time was 300 minutes. Cardiopulmonary bypass time was 80 minutes and aortic cross-clamp time was 26 minutes. The LVOT diameter increased from approximately 15–16 mm preoperatively to 19–20 mm following surgical correction. The patient was transferred to the intensive care unit without inotropic support and was successfully extubated two hours after ICU admission. She was transferred to the ward on postoperative day 2 and discharged home on postoperative day 6 without complications. Result Adult DSS is an uncommon cause of fixed LVOT obstruction and may be overlooked during the evaluation of patients presenting with high outflow gradients. In this case, perioperative TEE accurately characterized the lesion, guided surgical planning, and demonstrated excellent correlation with operative findings. Optimized anesthetic management facilitated a fast-track recovery pathway characterized by the absence of inotropic support, early extubation, and short ICU stay. Conclusion Perioperative TEE plays a pivotal role in the diagnosis and management of adult DSS. Accurate anatomical characterization facilitates appropriate surgical planning and favorable perioperative outcomes. This case demonstrates that TEE-guided management combined with optimized anesthetic care can support rapid postoperative recovery following surgical correction of DSS.