Transcatheter Aortic Valve Implantation (TAVI)

Transcatheter Aortic Valve Implantation, or more commonly known as TAVI, is a biological valve replacement procedure performed in patients with severe aortic stenosis, usually by entering through the groin vessel, without cutting the chest cage and without stopping the heart. This method allows a new valve to be placed via a catheter inside the old valve that has narrowed due to calcification and prevents the heart from pumping blood. Preferred especially in elderly or high-risk patients who cannot tolerate open-heart surgery, this non-surgical treatment option is one of the most important life-saving interventions of interventional cardiology thanks to shortening the hospital stay and offering the possibility of rapid recovery.

What Is Transcatheter Aortic Valve Implantation (TAVI)?

Transcatheter Aortic Valve Implantation (TAVI) is a minimally invasive method that enables severe aortic valve stenosis to be treated without open-heart surgery by implanting a bioprosthetic valve via a catheter. It is usually performed through the femoral artery. It is especially preferred in elderly patients or those with high surgical risk. Significant improvement in symptoms can be achieved after the procedure, and the length of hospital stay is generally short.

Why Does Aortic Stenosis Occur and What Problems Does It Cause in the Body?

You can think of your heart as the main pump that supplies your home’s plumbing system, and the aortic valve as the valve at the outlet of this pump. Over the years, just as limescale clogs pipes, calcium begins to accumulate on these valve leaflets. We call this degenerative aortic stenosis. The valve stiffens, loses its flexibility, and becomes unable to open.

This condition increases the heart’s workload tremendously. The heart has to work with much higher pressure to send blood to the body through a narrowed opening. At first, the heart muscle thickens to adapt to this challenge, in a sense “building muscle.” But as the process progresses, the heart becomes tired and can no longer pump blood strongly enough. This means less clean blood reaches the brain, kidneys, and other organs. If not treated, this mechanical obstruction unfortunately leads to heart failure and life-threatening risks.

With Which Symptoms Do Our Patients Apply to Us, and How Is Aortic Stenosis Recognized?

This disease progresses insidiously. Until the valve opening narrows to a critical level, our patients usually do not feel any complaints. However, when the stenosis reaches the “severe” level, symptoms begin to appear. The sentence I hear most often from my patients who come to the clinic is: “Doctor, I can no longer climb the hill I used to climb; I get blocked right away.” This is the clearest sign that the heart can no longer meet the body’s increased oxygen demand during exertion.

The most typical symptoms of the disease are:

• Shortness of breath
• Easy fatigue
• Chest pain
• Dizziness
• Fainting
• Palpitations

Among these symptoms, especially fainting and chest pain tell us that the disease has reached a very critical stage and must be treated without delay. Making the diagnosis is quite easy for us; the very loud “murmur” sound we hear when we listen to the heart raises suspicion, and with echocardiography (heart ultrasound) we can clearly see how narrowed the valve is.

Why Is Medication Alone Not Sufficient for Aortic Stenosis?

When talking with our patients, the moment we encounter most often and struggle the most to explain is the moment we tell them that a medication cannot solve this. Human nature wants to heal without surgery, with medication. However, aortic stenosis is not a biochemical disorder in the body but a completely mechanical problem. There is still no medication invented in the world that can open a calcified, stone-like valve structure or dissolve that calcification.

The diuretics or heart medications we prescribe only relieve the patient’s shortness of breath a little and reduce fluid retention, but they do not eliminate the main problem, namely the narrowing of the valve. As long as the stenosis remains, the deadly pressure on the heart continues. Therefore, when symptoms begin, we must treat the mechanical problem with a mechanical solution, that is, by replacing the valve. Otherwise, the life expectancy of symptomatic patients followed with medication alone is unfortunately quite short.

What Are the Advantages of the TAVI Method Compared to Open Surgery?

Traditional open-heart surgery (SAVR) requires the breastbone (sternum) to be cut from top to bottom, the chest cage to be opened, and the patient to be connected to a heart-lung machine with the heart stopped. This is a very effective and proven method, but it is a major trauma for the body. Bone healing takes months, and returning to normal life takes time.

TAVI is the approach we call “minimally invasive,” which causes the least harm to the body. Its biggest difference and advantage is that the chest cage is not opened. We interventional cardiologists usually perform the procedure by entering through the groin vessel (femoral artery). There is no scalpel scar on your skin, and your bones are not cut. More importantly, during the TAVI procedure, anesthesia is not given, and the heart is not stopped. While the heart continues to beat in its own rhythm, we place the new valve in position. In this way, our patients do not have to stay in intensive care for days, the risk of infection decreases, and they can get up and return home much more quickly.

In Which Patient Groups Is TAVI Considered as the First Choice?

When TAVI first emerged, it was applied as a “last chance” only for very old and frail patients who were said to be impossible to operate on. However, with the tremendous success rates obtained over the last 15 years and the development of technology, its area of use has now expanded greatly. In light of guidelines and our clinical experience, we select patients very meticulously.

The priority groups for TAVI are:

• Patients over 75 years of age
• Those with high surgical risk
• Those who have had prior open-heart surgery
• Those with chest structure deformities
• Patients with a porcelain aorta
• Those with severe lung disease

Especially for a patient over 75 years of age, the long recovery process and complication risks of open surgery are very high. In this age group, we can say that TAVI is now the gold standard. In patients between 65 and 75 years of age, we decide by looking at the patient’s biological age, activity level, and anatomical structure. In younger patients under 65, we still consider the surgical option as a strong alternative by taking into account the lifespan of the bioprosthetic valve that is implanted.

How Does the Heart Team Play a Role in the Decision-Making Process?

In modern medicine, especially for life-critical situations such as the heart, I cannot decide on the treatment method to be applied alone, and I should not. In our hospital, we have a “Heart Team” council that convenes:

This council includes the following specialists:

• Interventional cardiologists
• Cardiovascular surgeons
• Anesthesiologists
• Radiologists
• Echocardiography specialists

We put all of the patient’s tests on the table. Our surgeon colleague says, “If I operate on this patient, these will be the risks,” and we say, “If we do TAVI, these will be the advantages and disadvantages.” We discuss everything, not only the patient’s heart but also general frailty, mental status, kidney functions, and even social support. With collective reasoning, we choose the method that will be the safest, most comfortable, and longest-lasting for the patient. This approach minimizes the margin of error.

Why Is the Pre-Procedure CT Scan So Important?

For every patient for whom we decide on TAVI, we обязательно obtain a very detailed computed tomography scan in which we can perform millimetric measurements. This is our roadmap, our navigation. In open surgery, the surgeon can open the heart and see and measure the valve directly, but we do not have that chance because we proceed from inside the vessel. We have to know everything in advance, before the patient is even on the table.

The parameters we assess on CT are:

• Aortic annulus diameter
• Calcification density
• Coronary artery height
• Width of the groin vessels
• Vessel tortuosity

We must measure the diameter of the ring (annulus) where the valve will sit down to the millimeter. If we choose a valve that is too small for the patient’s anatomy, the valve will not stay in place or will leak around the edges. If we choose a valve that is too large, we face the risk of tearing the aorta. In addition, we see on CT whether the groin vessels are wide enough to allow the passage of the materials we will use. If the groin vessels are blocked or too thin, we plan alternative access routes such as the shoulder vessel or neck vessel by looking at this CT as well.

Is General Anesthesia Mandatory During the TAVI Procedure?

In the past, we performed every TAVI case under general anesthesia, meaning we would fully put the patient to sleep and place a tube in the throat. However, as our experience increased and devices improved, we adopted the “minimalist approach.” We now perform the vast majority of our cases using only local anesthesia and light sedation (a calming medication).

The advantages of this method are:

• Faster recovery
• Not being connected to a ventilator
• Being able to communicate during the procedure
• Shorter intensive care stay
• Reduced risk of nausea and vomiting

The patient is as if in a deep sleep, does not feel pain, does not remember the procedure, but continues to breathe on their own. As soon as the procedure ends, we can talk with the patient. This provides great comfort and safety, especially for elderly patients with sensitive lungs. Of course, we may still prefer general anesthesia in situations where the patient cannot lie on their back or when the procedure is very complex, but our first choice is always the method that tires the patient the least.

How Is the New Valve Placed into the Heart and How Does It Start Working?

This is the most critical and technical part of the procedure. The new valve, in a crimped state, is located at the tip of the pencil-thick delivery system that we advance from the groin vessel. We reach the heart under fluoroscopy (X-ray) and position ourselves exactly inside the old, calcified valve. But there is a challenge: the heart is continuously beating and pumping blood. It is difficult to perform a millimetric placement in this moving environment.

Therefore, during the critical 10–15 seconds when we will deploy the valve, we deliver a rapid stimulation to the heart with the help of a temporary pacemaker, which we call “Rapid Pacing.” Using the temporary pacing wire placed in the right ventricle, we stimulate the heart at 180–200 beats per minute. When the heart is stimulated this fast, it cannot contract effectively; it only quivers, blood pressure drops, and in that low-blood-pressure moment we deploy the valve within seconds.

The valves we use are:

• Balloon-expandable valves
• Self-expanding valves

In balloon-expandable valves, we inflate a balloon inside to embed the valve into the calcified structure. In self-expanding (Nitinol) valves, when we retract the sheath, the valve expands with body temperature and seats itself in place. As soon as the new valve opens, it crushes and compresses the old diseased valve outward toward the sides. Immediately after the procedure, we stop the rapid pacing and the heart returns to its normal, strong beat within seconds. Now blood is pumped easily to the body because the obstruction in front of it has been removed.

What Are the Possible Risks and Complications of This Procedure?

As with every medical intervention, TAVI also has risks, and we discuss them openly with our patients. One of the most common situations we encounter is the need for a permanent pacemaker. The aortic valve lies very close to the main cables of the heart’s electrical system. If the new valve we implant puts pressure on these cables, electrical conduction may be impaired and the heart may slow down.

The main risks are:

• Need for a permanent pacemaker
• Leak around the edge of the valve
• Bleeding at the vascular access site
• Stroke
• Temporary deterioration in kidney function

The risk of a permanent pacemaker varies depending on the type of valve used, but it is between 5% and 8%. Another risk is “paravalvular leak.” If the new valve does not fully seat on the old calcified surface, it may leak from the edges. Mild leaks do not cause problems, but if there is significant leakage, we correct it with balloon post-dilation. The risk of stroke may occur when calcified fragments dislodge and travel to the brain during the procedure, but this risk is similar to surgery, and today we try to reduce it with protective filter systems.

What Is the Recovery and Discharge Process Like After TAVI?

The most pleasing aspect of TAVI is that the speed of recovery is almost miraculous. While it can take days for a patient who has had open surgery to leave intensive care, a TAVI patient is taken to their room a few hours after the procedure, eats, and talks with their family. If we performed the procedure through the groin and everything is going well, we get our patient out of bed and walking on the evening of the procedure or the next morning.

The length of hospital stay is generally as follows:

• 1 day (in some cases)
• 2–3 days (standard procedure)
• Longer if there is a complication

Early mobilization eliminates the risk of lung infection and clot formation due to immobility in elderly patients. When our patients are discharged, they often say, “Doctor, that pressure in my chest is gone, I can breathe comfortably.” This rapid clinical improvement is invaluable for both the patient’s psychology and physical recovery.

What Is Medication Use and Follow-Up Like After Discharge?

After returning home, the most important issue our patients need to pay attention to is blood-thinning medications. Although the newly implanted valve is a biological tissue, it takes approximately 3 to 6 months for the body to adapt to this valve and cover it with its own cells (endothelialization). During this period, it is vital to prevent clot formation on the valve.

The standard medications used are:

• Aspirin
• Clopidogrel
• Gastric protector
• Blood thinners if there is a rhythm disorder

If we have not placed a stent recently, we give our patient a single antiplatelet (aspirin or clopidogrel) for a period. However, if the patient has a pre-existing rhythm disorder (atrial fibrillation), we customize the treatment plan accordingly. In addition, before procedures such as tooth extraction that involve bleeding or carry an infection risk, we ask patients to consult us обязательно and to use prophylactic antibiotics (prophylaxis). Because bacteria from the mouth can enter the bloodstream and settle on the new valve (endocarditis). We perform routine follow-ups at 1 month, 6 months, and 1 year to closely monitor valve function.