Transesophageal Echocardiography and Clinical Significance of Giant Eustachian Valve during Cardiac Surgery: A Narrative Review.

The Eustachian valve (EV), an embryologic remnant of the right valve of the sinus venosus located at the inferior vena cava (IVC)-right atrial (RA) junction, is typically a small and clinically insignificant structure. However, a prominent, large, or giant EV can present important challenges during cardiac surgery and cardiopulmonary bypass (CPB). This review summarizes the perioperative implications, echocardiographic identification, and management strategies associated with large EVs in adult cardiac surgical patients. A narrative literature review was conducted using PubMed, Scopus, and Embase databases from inception to March 2026. Available evidence indicates that large EVs may obstruct IVC cannula flow, resulting in inadequate venous drainage and suboptimal CPB performance. The increasing adoption of minimally invasive cardiac surgery (MICS) has further highlighted the importance of EV recognition, as prominent valves may impede guidewire passage and femoral venous cannula positioning, compromising venous return during CPB. Large EVs may also increase the risk of right atrial or IVC injury during cannulation and facilitate paradoxical embolism by directing venous blood flow toward a patent foramen ovale. In addition, prominent EVs are frequently misidentified on transesophageal echocardiography (TEE) as right atrial thrombi, tumors, vegetations, or intracardiac devices, potentially leading to diagnostic confusion and inappropriate interventions. Intraoperative two-dimensional and three-dimensional TEE, particularly the mid-esophageal bicaval view, remains the most reliable modality for identification. Real-time TEE-guided cannulation, careful surgical planning, selective prophylactic resection, and meticulous de-airing strategies can minimize associated complications. Routine pre-CPB TEE assessment and standardized management algorithms may improve procedural safety and perioperative outcomes in this uncommon but clinically significant anatomical variant.