What Is Transesophageal Echocardiography (TEE)? Which Conditions Is It Used For?

Transesophageal echocardiography (TEE) is a semi-invasive cardiological diagnostic method that provides high-resolution imaging of the anatomical structure, chambers, and valves of the heart with the help of a special ultrasound probe advanced into the esophagus. This advanced technology is used in the definitive diagnosis of critical diseases such as heart valve regurgitation and stenosis, congenital heart defects, suspected intracardiac clots associated with atrial fibrillation, aortic tears, and infective endocarditis (inflammation inside the heart). Preferred when standard external chest ultrasound is insufficient due to physical barriers, this system enables physicians to evaluate the most hidden structures of the heart simultaneously, in three dimensions, and with crystal clarity, thereby allowing the most appropriate treatment strategy to be established.

Why Is Transesophageal Echocardiography (TEE) Different From Standard Echocardiography?

The first method that comes to mind in the diagnosis of heart diseases and is frequently used in evaluation is standard transthoracic echocardiography, which is performed by applying gel to the skin from outside the chest. In this method, which is quite easy for patients, sound waves attempt to reach the heart by passing through various physical barriers such as the rib cage, ribs, muscle tissue, and lungs. As sound waves pass through these tissues, they may lose some of their strength or lose quality through reflection. This condition, known in medical terminology as a “poor acoustic window,” may prevent certain delicate structures from being evaluated clearly. We can think of the functioning structure of the heart as a house with rooms, doors, and walls; when viewed from the outside, a small hinge problem inside may occasionally be overlooked. However, anatomically, the esophagus lies directly against the posterior wall of the heart. The TEE procedure, performed by advancing a thin and flexible tube with a tiny ultrasound sensor at its tip into the esophagus through the mouth, eliminates all the external barriers mentioned above. The sensor is so close to the heart that fine calcifications in the heart valves, small tissue damage, or small clots that may form in hidden chambers of the heart can be seen in considerable detail.

Some conditions in which standard ultrasound may be insufficient or imaging may become difficult are as follows:

• Advanced lung diseases
• Emphysema
• Obesity
• Chest wall deformities
• Thicker-than-normal muscle tissue

When such physical factors are present, TEE is used to prevent delays in diagnosis and to select the most appropriate treatment approach. Especially if an intervention will be performed on the heart valves, viewing the source of the problem from inside at high resolution contributes greatly to the success of the treatment process.

Which Steps Are Followed During the Preparation Process Before Transesophageal Echocardiography (TEE)?

The process of imaging the heart from inside is planned with great care, always prioritizing patient comfort and safety. One of the most critical steps in the preparation process is for patients to remain completely without food or water for a certain period before the procedure. This fasting period, which usually lasts six to eight hours, helps greatly reduce unwanted situations such as stomach contents flowing backward through the esophagus and entering the respiratory tract during the procedure. The patient’s medical history is reviewed in detail by the physician, as the esophagus is a highly sensitive internal tissue.

Some anatomical and health conditions that must be evaluated before the procedure are as follows:

• Difficulty swallowing
• Esophageal stenosis
• Advanced hiatal hernia
• Severe gastric reflux
• Esophageal diverticulum

Previous digestive system surgeries

When the patient is taken into the procedure room, if there are removable teeth or dentures in the mouth, they are temporarily removed for safety. The procedure is generally well tolerated by patients and may cause slight discomfort rather than pain. A locally acting anesthetic spray is applied to the back of the throat to calm the gag reflex and help the person relax. In addition, sedatives administered intravenously place the patient into a light sleep, allowing the process to be completed in an extremely calm and comfortable manner. Thanks to these steps, patients usually do not feel the procedure.

What Conditions and Risks Prevent Transesophageal Echocardiography (TEE) From Being Performed?

As with every medical procedure, there are certain conditions that require this imaging procedure to be postponed or special precautions to be taken. Diseases that disrupt the physical structure of the esophagus or damage tissue integrity may make it difficult to advance the imaging device safely. The primary goal while advancing the ultrasound tube into the esophagus is to avoid even the slightest damage to the surrounding tissues.

The main conditions that may restrict or prevent the TEE procedure are as follows:

• Active upper gastrointestinal bleeding
• Esophageal cancers
• Tears in the esophageal wall
• Abnormal openings between the trachea and esophagus
• Advanced tissue narrowing

In such sensitive medical conditions, the physicians managing the process prefer to use alternative imaging methods. Safety management during the procedure is carried out very carefully. While the oxygen level in the blood is monitored continuously with a small sensor placed on the fingertip, the heart rhythm and blood pressure values from the arm are continuously monitored through electrodes attached to the chest. Very rarely, fluctuations in oxygen levels or rhythm changes may occur; however, these situations are quickly brought under control with the available medical equipment. The most common condition experienced by patients after the procedure is a mild burning or stinging sensation due to the effect of the spray used to numb the throat. Since swallowing function is expected to return to normal only after the numbness in the throat has completely subsided, patients are generally advised not to consume any food for several hours after the procedure.

Why Is TEE Indispensable in the Treatment of Mitral Valve Regurgitation With Clipping (MitraClip)?

The mitral valve, located between the left atrium and ventricle of the heart, is a valuable mechanism that works in one direction during the journey of blood from the lungs to the heart and then to the body. Over time, the leaflets of this valve may stretch, the tissue structure may deteriorate, or their edges may no longer come into contact with each other due to enlargement of the heart chamber. When the valve cannot close completely, some of the blood that should be pumped leaks backward toward the lungs. This condition, known as mitral regurgitation, may cause shortness of breath and lead to heart fatigue over time. For patients who cannot tolerate open surgery due to advanced age or additional conditions, the MitraClip method, in which the valve is grasped from the middle with a clip by entering through the groin vessel with very thin wires, is frequently preferred. The only device that acts as the eye of this repair procedure performed within a completely closed system is TEE.

The anatomical parameters examined before the procedure to determine whether the mitral valve is suitable for this repair are as follows:

• The length of the area where the leaflets come into contact with each other
• The depth at which the valves prolapse toward the ventricle
• The amount of separation between the leaflets
• The current thickness of the valve tissue
• The width of the valve opening area

As a result of these evaluations, during the intervention of a patient found suitable for the procedure, all movements of the physician performing the procedure are coordinated through the ultrasound screen. In this way, the safe point at which the thin membrane inside the heart must be punctured while passing from the right atrium to the left atrium is marked. When the clip system reaches the targeted area, it is directed so that it is fully perpendicular to the closing axis of the valve. When the clip captures and closes both leaflets, whether the amount of backward blood flow has decreased to the desired level is analyzed with imaging. If necessary, the clip can be reopened and repositioned before being released, or a second clip can be added next to it for support.

How Is TEE Used During Left Atrial Appendage (LAA) Closure to Reduce the Risk of Stroke?

Atrial fibrillation is a very common rhythm problem in which the atria of the heart cannot contract rhythmically and regularly and instead quiver rapidly and irregularly. During this irregularity, some of the blood begins to pool in a blind pouch-like extension of the left atrium called the “left atrial appendage.” The tendency of blood that has lost its normal flow rate, slowed down, and accumulated to clot over time is a condition that requires careful attention. This is because if a clot formed in this area enters the bloodstream and reaches the cerebral vessels, it may cause serious conditions such as stroke. Blood-thinning treatments are given to patients to keep these risks under control. However, patients who have experienced severe gastric bleeding or have a tendency to bleed may be unable to use these medications. At this stage, minimally invasive procedures are performed to protect patients by closing the opening of this pouch with a plug-like device.

The vital anatomical features examined with TEE during the procedure are as follows:

• A fresh clot formed inside the pouch
• The anatomical internal depth of the pouch
• The exact width of the appendage opening
• The tissue lobes of the pouch
• The structure of the area where the device to be used will be positioned

The first and most critical rule of the evaluation is to investigate whether there is a clot inside the pouch shortly before the procedure. If a clot is detected inside, the intervention is postponed because there is a possibility that it may become dislodged during the procedure. When it is understood that there is no clot, the depth of the pouch and the width of its opening are measured from different angles. The device selected in a size that will safely close the opening of the pouch is placed in this area with the help of a catheter. After the device is placed, small pulling tests are performed to check whether it is firmly attached and whether any gaps remain around its edges. This follow-up process is part of a long-term plan aimed at improving the patient’s quality of life.

How Does TEE Guide the Closure of Congenital Heart Defects (ASD and PFO) With a Patch?

During the formation and development stage in the womb, there is a natural blood passage between the right and left atria of babies’ hearts. This passage, which usually closes and disappears shortly after birth, may remain open for life in some individuals. These openings, known as Atrial Septal Defect (ASD) or Patent Foramen Ovale (PFO), may sometimes create different pressure imbalances within the heart and cause certain health complaints later in life.

The main problems that such congenital heart defects may cause are as follows:

• Mixing of oxygen-rich and oxygen-poor blood between the chambers
• Unwanted enlargement of the right side of the heart
• Increase in pulmonary blood pressure
• Severe and resistant recurrent migraine attacks
• Blood clots in the body passing through the defect and traveling to the brain

These congenital defects, which were repaired with patches by opening the chest in previous years, can now be treated much more practically with advanced methods. Special devices in the form of a double disc or a tiny umbrella are carefully placed into the defect by entering through a vessel in the groin and extending to the heart. TEE guides the physician at every stage of the procedure. Before closure, the exact shape of the defect, its maximum diameters, and the adequacy of the surrounding heart tissue required for the device to hold firmly are evaluated on the screen. Since some openings may be oval rather than perfectly round, correctly determining the volume of the area to be closed is extremely important. During the procedure, color flow technology is used to view live whether the closure device has settled into the defect and stopped the flow between the two atria, and the treatment is completed.

How Does TEE Facilitate the Repair of Leaks Remaining From Previous Surgeries (Paravalvular Leak)?

In patients who previously underwent surgical interventions and received mechanical or biological prosthetic valves due to severely damaged heart valves, tissue fatigue or minor infections may be observed in the valve tissue over the years. These developments may cause millimetric separations to form along the suture lines where the prosthetic valve is attached to the heart. The backward leakage of blood through these small gaps that open between the artificial valve and the heart wall is called “paravalvular leak” in medicine.

The conditions that this leak may cause in the patient’s general health are as follows:

• Increased complaints of shortness of breath
• Restriction in daily physical activities
• Emergence of symptoms of heart failure
• Breakdown of red blood cells in the leakage area
• Persistent anemia causing weakness

The general health condition of these patients may often be too fragile to tolerate the burden of a second open heart surgery. Therefore, closed interventional methods based on entering through a catheter and placing a tiny plug in the leakage area come to the forefront. Locating this leak and understanding its structure in a beating heart is a highly challenging process. TEE divides the structure of the heart into segments like a clock face and shows the physician the exact clock-position location of the leak. Thanks to this detailed map, the physician safely passes an extremely thin guidewire through the leaking channel. The closure material advanced over the wire is opened and blocks the leak. At the end of the procedure, the success rate of the treatment is increased by determining that the blood leakage has decreased or completely stopped.

Which Safety Stages Does TEE Provide During Balloon Treatment (PMBV) of Rheumatic Heart Valve Stenosis?

Rheumatic fever experienced during childhood or adolescence may lead to certain physical and anatomical changes in the mitral valve of the heart after many years. As a result of these changes, the heart valves may thicken and lose their flexibility, fuse at their edges, and cause stenosis that makes the passage of blood from one chamber to another very difficult. In this condition called mitral valve stenosis, if the anatomical structure of the valve is evaluated and found suitable, balloon dilation treatment performed without the need for surgery provides significant relief for patients. A deflated balloon placed inside the valve with a thin system is inflated, separating the fused tissues and allowing the valve to reopen. TEE examinations are among the greatest aids in carrying out this delicate process.

The features examined when evaluating the patient’s suitability before balloon dilation treatment are as follows:

• The overall thickness of the valve tissue
• The ability of the valves to open and stretch
• The density of calcification around the valve
• The general structure of the supporting tissues beneath the valve
• The presence of a clot that has remained inside the atrium

The most important factor that determines the course of the procedures is whether a clot has developed in the stagnant blood within the left atrium, which has enlarged due to the valve stenosis. If a clot is detected in the heart chamber, the procedure is abandoned because movement of the balloon or catheter wires in the area may dislodge the clot and cause it to travel toward the brain. If the valve structure is suitable for the balloon procedure and no clot is observed, the physician performing the procedure safely crosses the membrane between the atria with visual guidance from the screen and repairs the stenosis in the valve.

What Are the Benefits of Using TEE During Emergency Interventions and Cardiac Massage?

Although cardiac interventions performed with closed methods in interventional procedure rooms take place in safe environments, because the heart is a highly sensitive organ, critical conditions requiring immediate intervention, such as sudden rhythm problems, cardiac arrest, or a rapid drop in blood pressure, may very rarely develop. At such moments, when even seconds are important, cardiac massage support is immediately provided to the patient. Under normal circumstances, during external echocardiography, cardiac massage may occasionally need to be interrupted in order to image the heart. However, when an imaging device is already positioned in the esophagus in such rooms, the condition of the heart can continue to be monitored continuously without interrupting the vital compression movements applied to the chest.

Some health problems that can be rapidly diagnosed through the ultrasound screen in emergencies are as follows:

• Sudden migration of a clot to the main pulmonary vessels
• Accumulation of fluid or blood in the membrane surrounding the heart
• Sudden structural separations that may occur in the arteries
• Regional loss of contraction in the heart walls
• Weakening of the pumping power of the heart muscle

Frequently Asked Questions

Prof. Dr. Kadriye Kılıçkesmez

Prof. Dr. Kadriye Orta Kılıçkesmez is one of the leading figures in the field of Turkish cardiology. She was born on January 24, 1974, in Tekirdağ. After completing her undergraduate education at Istanbul University Cerrahpaşa Faculty of Medicine, she chose cardiology as her specialty and received her specialist training at the Cardiology Institute of the same university. In 2015, she was appointed by the university to establish the Şişli Etfal cardiology clinic and Angio laboratory. Becoming a professor in 2017, Kadriye Kılıçkesmez established the cardiology clinic and Angio laboratory of Prof. Dr. Cemil Taşçı Hospital in 2020 and ensured that the clinic became a training clinic.