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

Abstract

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.

INTRODUCTION

The Eustachian valve (EV) (valve of the inferior vena cava [IVC]) is a thin, crescent-shaped fold of endocardium located at the anterior margin of the IVC orifice in the right atrium (RA). Embryologically, it is the remnant of the right valve of the sinus venosus, which in fetal life directs oxygenated blood from the IVC across the foramen ovale into the left atrium. In most adults, this structure regresses to a small, clinically insignificant ridge. However, in a minority of adults, it persists as a prominent, sail-like, fenestrated, or aneurysmal structure. A fenestrated and incompletely resorbed remnant may persist as the web-like Chiari network.[1,2,3,4]

Although often considered an incidental finding, a large EV carries important implications for cardiac surgery and perioperative echocardiography. It may mimic right atrial masses such as thrombi, vegetations, myxomas, or catheter-related artifacts. The principal surgical concern is interference with IVC cannulation during cardiopulmonary bypass (CPB), resulting in inadequate venous drainage, venous hypertension, or vascular injury.[5,6] In addition, a large EV may facilitate paradoxical embolism by directing IVC flow across a patent foramen ovale (PFO) or atrial septal defect (ASD), and it may obscure surgical exposure during ASD closure, tricuspid valve surgery, or transseptal mitral valve procedures.[7,8,9,10]

This narrative review synthesizes current evidence on the embryology, echocardiographic characteristics, hemodynamic implications, and surgical management of large EVs. The aim is to provide a practical, evidence-based framework for cardiac anesthesiologists and surgeons to identify, anticipate, and mitigate complications associated with this underrecognized anatomic variant.

METHODS

This narrative review was conducted using a structured search of PubMed, Scopus, and Embase from inception through March 2026. Search terms included “Eustachian valve,” “giant Eustachian valve,” “Chiari network,” “cardiac surgery,” “cardiopulmonary bypass,” “transesophageal echocardiography,” “minimally invasive cardiac surgery,” “IVC cannulation,” “venous drainage failure,” “percutaneous IVC cannulation,” and “right atrial mass.”

Inclusion and exclusion criteria

Case reports, case series, observational studies, and review articles involving adult cardiac surgery and describing diagnosis, intraoperative decision-making, and complications caused by prominent EVs and/or Chiari networks were included in the study. Reports limited exclusively to congenital heart surgery or nonsurgical interventional cardiology were excluded from the study. Data were extracted and synthesized to describe embryology and anatomy, echocardiographic diagnosis, cannulation-related difficulties during CPB, surgical interference, EV-related complications, and mitigation strategies. Reference lists of eligible articles were also manually screened. A total of 47 publications were included, comprising 28 case reports, 12 case series, 5 observational studies, and 2 expert guideline or consensus documents.

Embryology and anatomic spectrum

Embryological origin

During the 4^th week of gestation, the sinus venosus receives blood from the vitelline, umbilical, and common cardinal veins. The right and left venous valves fuse cranially to form the septum spurium and caudally contribute to the formation of the EV and the valve of the coronary sinus (Thebesian valve). Normally, the left venous valve and the superior part of the right venous valve regress. Failure of regression results in a prominent EV or, when fenestrated, a Chiari network.[1,2,4]

Anatomic variants and prevalence

Large or giant EVs can be classified morphologically into three broad types. Type I is a sail-like, smooth, nonfenestrated membrane extending more than 1 cm into the RA and is the most common surgical variant. Type II is a fenestrated structure containing one or more openings and is associated with a higher risk of catheter entrapment or guidewire misdirection. Type III is an aneurysmal form, appearing as a dilated pouch-like structure capable of trapping thrombus or air, thereby increasing thromboembolic risk, particularly in the presence of a PFO or ASD.[7,8,11]

The EV is bounded anteriorly by the crista terminalis, posteriorly by the IVC orifice, and medially by the fossa ovalis and coronary sinus ostium. Its proximity to the AV node and tendon of Todaro makes it surgically sensitive. Anatomical studies report EV lengths ranging from a small ridge to more than 3.0 cm. Valves longer than 1.0 cm may be considered large, whereas those exceeding 2.0 cm may be considered giant. A prominent EV has been reported in approximately 7%–10% of adult hearts, whereas truly giant EVs appear to be uncommon.[2,7,11,12,13]

Transesophageal echocardiographic identification and differential diagnosis

Transesophageal echocardiographic knobology and optimal views

Transesophageal echocardiography is the imaging modality of choice for intraoperative EV identification because it provides superior resolution of the IVC-RA junction compared with transthoracic echocardiography. 14,15 The midesophageal (ME) bicaval view at 90°–110° is the most useful standard view for defining the EV, its mobility, and its point of attachment. In this view, the EV appears as a thin, mobile, echogenic linear structure continuous with the anterior margin of the IVC-RA junction[14,15,16] [Figure 1]. A modified ME bicaval view obtained by slight anteflexion and clockwise rotation at the same imaging depth may bring the EV into sharper focus against an IVC cannula. This is particularly useful during central or percutaneous venous cannulation in minimally invasive cardiac surgery. Biplane (X-plane) imaging offers simultaneous orthogonal planes and improves assessment of the EV’s true attachment and spatial extent[14,15,16,17] [Figure 2]. A modified ME four-chamber view focused on the RA, tricuspid valve, and RV may show the EV extending toward the tricuspid valve and occasionally prolapsing into the RV during diastole, thereby mimicking vegetation or abnormal tricuspid tissue. Real-time 3D Transesophageal echocardiographic (TEE) provides an en face view of the EV in relation to the IVC orifice, fossa ovalis, and coronary sinus, and is useful in distinguishing EV from Chiari network or right atrial tumors and thrombi[12,15,17] [Figure 3]. A practical pre-CPB TEE screening protocol may include the following steps: obtain the ME bicaval view at 90°–110° with X-plane imaging when possible; identify the IVC-RA junction and trace any linear structure to its origin; assess EV length, thickness, mobility, and fenestration; use color Doppler to assess flow streaming toward a PFO or ASD; and document EV morphology in the pre-CPB TEE report[14,15,16,17] [Figures 1 and 2].

Figure 1.

Transesophageal Echocardiography: Midesophageal bicaval view for evaluation of giant eustachian valve (EV) and co-existing ostium secundum atrial septal defect (OS-ASD). Mid-esophageal (ME) bicaval view for evaluation of giant EV: (a) shows ME bicaval view at 106° demonstrating a giant EV co-existing with an OS-ASD (It is mimicking like the J-tip guidewire inserted for percutaneous inferior vena cava [IVC] cannulation but can easily be differentiated by absence of “comet-tail” or “ring down” reverberation artifacts arising from the metal structure like a guidewire). Note the “sail-like” extension of the giant EV into the right atrium, continuous with the IVC rim (arrow). (b) shows postoperative ME bicaval view at 115° after pericardial patch closure of ASD and excision of the EV. EV = Eustachian valve, LA = Left atrium, RA = Right atrium, SVC = Superior vena cava, IVC = Inferior vena cava, ASD = Atrial septal defect

Figure 2.

Transesophageal Echocardiography: Bi-plane (X-Plane) Mid-Esophageal (ME) bicaval view for evaluation of eustachian valve (EV) attachment to inferior vena cava (IVC)-RA Junction. Biplane (X-Plane Transesophageal Echocardiography. X-plane (biplane) TEE at the ME bicaval view demonstrating anatomical orientation of EV. (a) shows biplane interrogation of bicaval plane (90°–110°) at the tip of EV while (b) shows the biplane interrogation of EV at its IVC-RA attachment. EV is seen as a thin, mobile ridge at the IVC–right atrial (RA) junction. (c) demonstrates the color Doppler to appreciate the IVC blood flow directed towards the fossa ovalis region. Biplane (X-plane) image provides a perpendicular section through the valve, confirming its thickness, mobility, and spatial relationship to the coronary sinus ostium and interatrial septum. This multiplanar approach differentiates the EV from adjacent structures (Thebesian valve, crista terminalis) and excludes pathologic masses, facilitating anatomic guidance during transseptal puncture and structural interventions. EV = Eustachian valve, IVC = Inferior vena cava, RA = Right atrium, SVC = Superior vena cava, LA = Left atrium, CS = Coronary sinus, IAS = Interatrial septum

Figure 3.

Transesophageal Echocardiography: Mid-Esophageal (ME) Bicaval View and Live 3D TEE Imaging of RA Myxoma Originating From inferior vena cava (IVC)-RA Junction with Co-existing ostium secundum atrial septal defect (OS-ASD). Transesophageal Echocardiography: ME Bicaval View and Live 3D TEE Imaging for evaluation and differential diagnosis of Eustachian valve (EV). Panel A shows a modified ME aortic valve short axis view at 64° demonstrating a right atrial myxoma originating from IVC-RA junction and protruding into left atrium through a co-existing OS-ASD. It can easily be differentiated by absence of thin and filamentous “sail-like” extension into the right atrium as seen usually in EV. Panel B shows mid esophageal live 3D bicaval view at 95° demonstrating the RA myxoma with peduncle attached to the IVC-RA junction. LA = Left atrium, RA = Right atrium, SVC = Superior vena cava, IVC = Inferior vena cava, ASD = Atrial septal defect

Differential diagnosis

A large EV must be differentiated from both benign and pathological right atrial structures. The key diagnostic maneuver is tracing the structure to its origin in multiple planes. A structure arising from the anterior IVC margin and moving synchronously with IVC inflow is most consistent with an EV. Biplane and real-time 3D TEE are particularly valuable when two-dimensional views are equivocal.[12,14,15,16,17] Table 1 summarizes the important echocardiographic features that help distinguish a giant EV from its common mimics.

Table 1.

Differential diagnosis and transesophageal echocardiographic features of giant eustachian valve

Structure		Echocardiographic features		Key differentiator
Giant EV		Thin, mobile, linear; continuous with IVC rim		Originates from anterior IVC margin
Chiari network		Fenestrated, web-like, highly mobile, chaotic motion		Multiple attachments (IVC, SVC, CS); lace-like
Right atrial thrombus		Nonmobile (or minimally mobile), heterogeneous, no IVC continuity		No continuity with IVC rim; often in RA appendage
Vegetation		Irregular, oscillating mass on valve leaflets/endocardium		Clinical sepsis; attached to tricuspid/pacemaker leads
Right atrial myxoma		Pedunculated, heterogeneous, attached to interatrial septum		Originates from fossa ovalis but rarely from EV
Catheter artifact		Linear echo moving with catheter manipulation, and produce “Comet-tail” or “ring down” effect due to reverberation artefact		Disappears when catheter is withdrawn
Crista terminalis		Fixed, muscular ridge along RA free wall		No mobility; lateral RA wall location

Summarizes key echocardiographic characteristics differentiating a prominent or giant Eustachian valve from other right atrial structures and pathologic entities that may mimic it on TEE. The “Key differentiator” column emphasizes distinguishing anatomical origins, mobility patterns, and attachment points that help avoid misinterpretation during intraoperative imaging. IVC=Inferior vena cava, SVC=Superior vena cava, CS=Coronary sinus, RA=Right atrium, TEE=Transesophageal echocardiography, EV=Eustachian valve

Hemodynamic and cardiopulmonary bypass-related implications

Challenges during inferior vena cava cannulation

The most important CPB-related complication of a giant EV or Chiari network is difficulty with, or occasional failure of, IVC cannulation. Repeated cannulation attempts may cause trauma, bleeding, RA-IVC dissection, or retroperitoneal hemorrhage.[5,6,18] A large EV may wrap around the cannula tip and obstruct venous drainage, tear during manipulation, or cause misdirection of a percutaneous guidewire during minimally invasive or femoral venous cannulation.[5,6,18] Real-time TEE guidance is strongly recommended during the guidewire and cannula advancement. The ME bicaval view allows confirmation of correct guidewire or cannula position and helps ensure that advancement occurs into the intended lumen rather than into a false passage created between the EV and atrial wall. When resistance is encountered, withdrawal and repositioning under direct vision is preferable to forceful advancement.[14,16,17,18] In severe cases, partial CPB established with SVC cannulation alone may allow safer insertion of the IVC cannula under reduced venous return and better visualization. Similar TEE-guided caution may be required during retrograde cardioplegia catheter placement.

Facilitation of paradoxical embolism

A large EV may preserve embryonic-like flow streaming in the RA, directing IVC flow toward a PFO or ASD. This may increase the risk of paradoxical embolism and postoperative stroke, independent of shunt size alone.[8,19,20] The same mechanism may contribute to refractory hypoxemia during CPB despite apparently adequate pump flow.[20,21]

Interference with retrograde cardioplegia delivery

Prominent EVs and Chiari networks may distort RA anatomy or obstruct the coronary sinus region, making retrograde cardioplegia cannula placement difficult. This should be suspected when positioning is unexpectedly difficult or retrograde pressure remains suboptimal despite repeated adjustments.[10,22]

Venous air lock and embolism

A prominent EV may trap air bubbles within the RA during de-airing and CPB separation. These bubbles may later be expelled into the pulmonary circulation or, in the presence of a PFO or ASD, into the systemic circulation, causing stroke or coronary air embolism.[22,23] Careful de-airing and TEE assessment of residual intracardiac air are therefore essential.

Impact of inadequate venous drainage and cardiopulmonary bypass efficiency

Obstruction of venous return due to EV-related cannula malposition may lead to venous hypertension, hepatic congestion, and the need for higher pump flows, thereby potentially increasing hemolysis and inflammatory activation. Angled or multistage IVC cannulas with softer tips may improve drainage. If obstruction persists, prophylactic EV resection or conversion to bicaval cannulation should be considered.[5,6,18,22]

Intraoperative surgical concerns linked to a giant or large eustachian valve

Obstruction of surgical exposure

During tricuspid valve surgery, a large EV may obscure the posterior and septal portions of the tricuspid annulus, complicating repair or replacement. Similarly, during transseptal mitral surgery, an EV or Chiari network may prolapse through the septostomy and hinder exposure of the mitral valve.[7,10,15] During surgical closure of an ASD, a large EV may be mistaken for the inferior rim of the defect. This can result in incomplete closure, diversion of IVC flow into the left atrium, residual shunting, or iatrogenic IVC stenosis if the EV is incorporated into the patch or suture line.[9,21,24]

Suture interference and inferior vena cava stenosis

EV tissue may be inadvertently caught in RA closure sutures, patch margins during ASD repair, or tricuspid annuloplasty sutures. This can lead to IVC stenosis, residual shunts, or tricuspid leaflet tethering. Recognition of the EV before closure, retraction during suturing, and TEE confirmation of IVC patency before chest closure are important preventive measures.[9,14,21,24]

Prophylactic resection versus conservation

Prophylactic resection of the EV may be considered when there is prior embolic history with associated PFO, significant interference with CPB cannulation or surgical exposure, aneurysmal morphology with suspected thrombotic risk, infective endocarditis, or intraoperative identification during planned PFO or ASD closure.[7,8,9,10,13,19,20] When excision is undertaken, the EV should be resected under direct vision after right atriotomy, leaving a small rim of tissue near the IVC-RA junction to avoid injury or stenosis. Tissue should be sent for histopathological examination when diagnostic uncertainty exists. Energy-based cautery close to the tendon of Todaro or the AV nodal region should be avoided.[2,13] A small, nonobstructive EV that does not interfere with cannulation or surgical exposure may be left intact. In such cases, simple retraction with a stay suture or atrial retractor is usually sufficient.[7,18]

Thromboembolism, infective endocarditis, and arrhythmogenic potential

Large EVs, especially aneurysmal variants, may create low-flow zones prone to thrombus formation. This risk may be amplified in patients with atrial fibrillation, low ejection fraction, or hypercoagulable states.[8,10,19,20] Infective endocarditis involving the EV is rare but well described, and it may be mistaken for right atrial myxoma.[13,25] Surgical resection is indicated when medical therapy fails or embolization occurs. Because of its proximity to the AV node, tendon of Todaro, and crista terminalis, the EV has a theoretical arrhythmogenic potential, although large-scale supporting data are lacking. Isolated reports have described significant right atrial inflow obstruction related to giant EVs.[2,10,18]

Table 2 summarizes the intraoperative surgical concerns linked to a giant or a large Eustachian valve, echocardiographic clues and technical modification as mitigation strategies. Table 3 summarizes postoperative complications and potential long-term sequelae of the large Eustachian Valve.

Table 2.

Intraoperative surgical concerns linked to large eustachian valve

Complication category		Specific event		Pathophysiologic mechanism		Intraoperative clue/TEE sign		Mitigation strategy
Venous cannulation and drainage failure		Inadequate CPB flow; venous hypertension		EV wraps around/occludes IVC cannula tip		Sudden drop in venous flow; TEE shows cannula tip abutting EV; CVP >15 mmHg		Reposition cannula under TEE; use angled IVC cannula; prophylactic EV resection; bicaval cannulation
Vascular injury associated with venous cannulation		IVC/RA tear or dissection; retroperitoneal hemorrhage		Forceful cannulation tears fenestrated EV or avulses base		New pericardial effusion; difficulty advancing wire/cannula; hypotension		Wire/cannula under direct TEE guidance; avoid blind advancement; immediate repair if tear occurs
Embolic events		Paradoxical air/thrombus embolism; stroke		EV traps air bubbles or thrombus; directs flow across PFO/ASD		Air lock in RA; new neurologic deficit post-CPB; color Doppler streaming across PFO		Aggressive RA de-airing with TEE; aspirate via IVC vent; close PFO; anticoagulation if thrombus
Diagnostic error		Misidentification as mass/thrombus/catheter		Large mobile EV mimics RA tumor or vegetation		Mobile linear structure continuous with IVC rim; no mass effect		Trace continuity to IVC in bicaval view; use 3D TEE; correlate with preoperative imaging
Surgical obstruction		Poor mitral/tricuspid exposure; prolonged cross-clamp time		EV blocks trans-septal or right atriotomy view		Surgeon reports “tissue in the way” during valve work		Retract EV with stay suture; excise if nonessential; 3D TEE guidance
Hemodynamic pseudo-shunt		Refractory hypoxemia on CPB; low SvO2		EV directs IVC flow across ASD/PFO (streaming)		Low SvO2 despite high pump flow; color Doppler streaming across PFO		Reposition IVC cannula; temporary PFO closure; adjust ventilator FiO2; close PFO definitively
Suture interference		IVC stenosis post-CPB; residual ASD shunt		EV caught in RA closure suture line or patch margin		High CVP, lower limb edema postoperation; residual shunt on TEE		Visualize EV before closure; retract with stay suture; confirm IVC patency with TEE before sternal closure

Summarizes intraoperative challenges and concerns arising from a large or obstructive EV during cannulation, exposure, and cardiopulmonary bypass. It highlights mechanisms, characteristic TEE findings, and practical mitigation strategies to reduce venous drainage failure, cannulationrelated injury, embolic events, and residual hemodynamic disturbances. CPB=Cardiopulmonary bypass, EV=Eustachian valve, IVC=Inferior vena cava, CVP=Central venous pressure, RA=Right atrium, ASD=Atrial septal defect, PFO=Patent foramen ovale, SvO₂=Mixed venous oxygen saturation, TEE=Transesophageal echocardiography

Table 3.

Postoperative complications and aftermaths/Long-term sequelae of long Eustachian valve

Complication		Incidence		Pathophysiology		Clinical presentation		Management
Paradoxical embolism (Onorato EM et al.)		Rare (case reports); EV increases PFO stroke risk 2.3-fold[8,19,20]		EV traps thrombus/air; directs across PFO		Stroke, MI, limb ischemia postoperative		Anticoagulation; PFO closure; EV resection if recurrent
Infective endocarditis (Maddury J et al.)		Very rare (<0.1%)[13,25]		Turbulent flow → endothelial damage → colonization		Fever, RA mass on TEE, sepsis		Prolonged antibiotics (4–6 weeks); surgical resection
Atrial arrhythmias		Theoretical; no large-scale data[7,18]		Proximity to AV node/crista terminalis		New-onset AFib/flutter post-CPB		Standard antiarrhythmic therapy; ablation if refractory
IVC stenosis		0.5%–1% (post-ASD repair)[9,24]		EV caught in suture line during RA closure		Lower limb edema, hepatic congestion, ascites		Surgical revision; balloon angioplasty if mild
Re-exploration for bleeding		Rare (1%–2%); reported in small series with traumatic EV/RAIVC injury[5,6,18]		EV tear during cannulation		Tamponade, high CVP, low Hb, mediastinal drain>200 mL/h		Return to OR; repair IVC/RA tear
Thrombus Formation (Roberts WC and Ko JM)		Rare; case reports[8,10,25]		Low-flow zone in aneurysmal EV		PE, stroke, or incidental TEE finding		Anticoagulation (warfarin/DOAC); resection if recurrent

Lists reported complications linked to a large or persistent EV in cardiac surgical and postoperative settings. Each event is described with its reported frequency, underlying pathophysiology, typical clinical manifestations, and suggested management based on available case reports and series. CPB=Cardiopulmonary bypass, EV=Eustachian valve, PFO=Patent foramen ovale, ASD=Atrial septal defect, MI=Myocardial infarction, RA=Right atrium, PE=Pulmonary embolism, DOAC=Direct oral anticoagulant, TEE=Transesophageal echocardiography, AV=Atrioventricular, IVC=Inferior vena cava, CVP=Central venous pressure

DISCUSSION

Eustachian valve, the silent partner in cardiopulmonary bypass related complications

This review emphasizes that a large EV is not merely an anatomical curiosity but a silent contributor to otherwise unexplained CPB complications. Inadequate venous drainage, refractory hypoxemia, paradoxical embolism, and difficult surgical exposure are often attributed to technical or physiological causes without recognizing the EV as the primary factor.[5,6,7,8,18,19,20,21] Systematic pre-CPB TEE evaluation of the IVC–RA junction can transform this overlooked structure into a predictable and manageable intraoperative finding. Early recognition informs cannulation strategy, prevents vascular injury, improves de-airing, and guides decisions regarding prophylactic resection when necessary.[14,15,16,17,18] Clinical reports have highlighted the risks and complications associated with due to the presence of large EV. Stump et al. described inadequate venous drainage due to a large EV wrapping around the IVC cannula, corrected by TEE-guided repositioning.[5] Tuna et al. noted giant EVs complicating cannulation and atrial exposure, prolonging bypass and cross-clamp times.[6] Lang et al. highlighted how prominent venous valves can alter RA inflow and shunt patterns, presenting as refractory hypoxemia or paradoxical embolism.[7] Onorato et al. demonstrated that large EVs or Chiari networks in patients with PFO act as independent risk factors for paradoxical thromboembolism.[8,19,20] Maddury et al. reported thrombus formation on EVs leading to recurrent pulmonary embolism.[10] Collectively, these observations support the EV as a “missing link” between anatomy and otherwise unexplained embolic or hypoxemic events.

TEE-based evaluation has been strongly advocated. Hahn et al. and Silvestry et al. recommended a deliberate RA and venous valve imaging in bicaval views.[14,15] Reeves et al. has recommended this to a routine perioperative TEE, emphasizing confirmation of venous cannula position at the IVC–RA junction.[16] Mahmood et al. has stressed that 2D, X-plane, and 3D TEE should guide cannulation type, trajectory, and repositioning when resistance is encountered.[17] Clinical case reports further illustrate the management of the giant EV. Stump et al. has demonstrated that redirecting the venous cannula away from a large EV restored venous return;[5] Tuna et al. emphasized anticipating difficult cannulation and planning bicaval cannulation or prophylactic EV resection;[6] Sideris et al. demonstrated that the excision of a persistent giant EV causing tricuspid inflow obstruction normalized the venous pressures and resolved the cyanosis.[18] Together, these findings highlight that deliberate EV assessment prevents vascular injury, optimizes de-airing, and informs when prophylactic resection is beneficial rather than incidental.

Mitigation strategies for eustachian valve-related cardiopulmonary bypass complications

Cannula repositioning under realtime TEE guidance can disengage it from the EV and restore venous return, and when obstruction persists, angled or multistage IVC cannulae, bicaval cannulation, or prophylactic valve resection can be considered.[5,6,17] Cannulationrelated vascular injury can be minimized by advancing guidewires and cannulae only under direct TEE visualization and treating any resistance as a signal to abandon the attempt and proceed to surgical repair if an IVC or right atrial tear is suspected.[5,17] Right atrial deairing should be meticulous, with continuous TEE surveillance and aspiration of air or thrombus via the IVC vent or RA sump, and closure of PFO or ASD can be undertaken when anatomy and risk profile warrant, with anticoagulation instituted if thrombus is detected on or near the valve.[8,10,19,20,25] Large mobile structures seen in the right atrium should be traced in multiple planes, confirmed with 3D or Xplane imaging, and correlated with preoperative studies before being labeled as mass or vegetation, to avoid misinterpreting a benign EV as a tumor or infective lesion.[9,12] If the EV obstructs transseptal or atrial exposure, it can be retracted with a stay suture or excised when nonessential and clearly impeding safe and efficient valve surgery.[6,7,18] In refractory hypoxemia with low SvO₂ on CPB, IVC cannula position can be adjusted to disrupt streaming across an ASD or PFO, FiO₂ can be increased and flows optimized, and definitive closure of the interatrial communication can be planned when indicated.[8,19,20,21] Before right atrial closure, the EV should be explicitly identified and retracted away from sutures or patch margins, and a final bicaval TEE with color Doppler can confirm unobstructed IVC inflow and absence of residual shunt, thereby preventing iatrogenic IVC stenosis and misdirected venous return[9,21,24] [Table 2].

Proposed transesophageal echocardiographic-based algorithm for clinical decision making on eustachian valve

Based on the currently available evidence, a structured intraoperative approach can be proposed. All patients undergoing cardiac surgery should undergo systematic pre-CPB TEE screening for EV using the ME bicaval view at 90°–110°, modified bicaval views, and X-plane imaging when available. The valve should be assessed for size, thickness, mobility, and fenestration, and color Doppler should be used to detect flow streaming toward a PFO or ASD.[14,15,16,17]

A practical risk stratification may classify valves smaller than 10 mm and nonmobile without associated PFO as low risk, valves 10–20 mm and mobile without PFO as moderate risk, and valves larger than 20 mm, highly mobile, aneurysmal, or associated with a PFO or ASD as high risk. Moderate-risk valves warrant TEE-guided cannulation with preference for angled cannulas. High-risk valves require a low threshold for prophylactic resection, meticulous cannulation under TEE guidance, and careful de-airing before separation from CPB.[8,14,15,16,17,18]

Following EV excision, TEE should be used to confirm right atrial and IVC integrity before chest closure. Post-CPB surveillance for unexplained hypoxemia or stroke should include reassessment for residual EV tissue, thrombus, or interatrial shunting[14,19,20,21] [Figure 4].

Figure 4.

Proposed transesophageal echocardiography (TEE) based algorithm for decision making on EV. It outlines the proposed TEE-based algorithm for the clinical decision making on EV. This sequential six-step algorithm outlines intraoperative evaluation and management of the EV using transesophageal echocardiography (TEE). Step 1 involves TEE evaluation with ME bicaval, X-plane, and 3D views. Step 2 identifies large or giant valves prompting advanced imaging. Step 3 stratifies risk by valve size and mobility, with thresholds at 10 mm and 20 mm based on echocardiographic measurements. Step 4 details management and mitigation strategies, emphasizing TEE-guided cannulation, prevention of iatrogenic inferior vena cava (IVC) injury, avoidance of atrioventricular node injury, and resection of EV when it interferes with IVC inflow or cannulation trajectory. Step 5 ensures aggressive de-airing and TEE assessment for residual air or injury. Step 6 integrates postoperative surveillance for hypoxia and patent foramen ovale, including immediate and follow-up TEE to exclude residual shunt, thrombus, or delayed hypoxemia. TEE = Transesophageal echocardiography, EV = Eustachian valve, IVC = Inferior vena cava, RA = Right atrium, PFO = Patent foramen ovale, ASD = Atrial septal defect, AV Node = Atrioventricular node

Limitations

This review is limited by the scarcity of large cohort studies. Most available evidence is derived from case reports, small case series, and retrospective observational studies. Publication bias likely overrepresents dramatic complications and may underestimate the prevalence of benign large EVs.

Future directions

Prospective multicenter registries that systematically document EV morphology on pre-CPB TEE and correlate findings with CPB complications are needed to better define incidence, mechanisms, and risk factors. Inclusion of EV assessment within future perioperative TEE recommendations would help standardize recognition and reporting. Comparative studies evaluating prophylactic EV resection versus conservative management in high-risk patients would further clarify optimal intraoperative management.

CONCLUSION

A large or giant EV is a clinically important anatomic variant capable of producing substantial perioperative complications in cardiac surgery. Its consequences range from diagnostic confusion on TEE and difficulty with IVC cannulation during CPB to increased risk of paradoxical embolism and impaired surgical exposure. Systematic pre-CPB TEE screening, early recognition, and a low threshold for corrective surgical management when interference is anticipated are essential to minimize preventable complications and improve perioperative outcomes.

Author contributions

ABS and GGS conceptualized and designed the study, conducted the literature search, acquired and analyzed the data and images, and drafted and critically revised the manuscript. APP and SSP contributed to the study design, literature review, and critical editing of the manuscript. RM and AG participated in study design, literature review, data interpretation, and manuscript preparation. TSS contributed to study design, literature review, and critical manuscript review and editing. All authors reviewed and approved the final version of the manuscript and agree to be accountable for all aspects of the work.

Ethics and consent statement

Written informed consent was obtained from the subjects for the use of de-identified transesophageal echocardiographic images for educational and scientific purposes. The confidentiality and anonymity was maintained throughout the preparation and publication of this manuscript.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.