Overview of Catheter Management of Aortic Valve Disorders
Aortic valve disease, specifically a condition known as aortic valve stenosis, is among the most common heart valve issues in the United States and across the globe. Historically, the main method of treating this was through open heart surgery to replace the aortic valve. However, a new method called transcatheter therapy has now gained significant importance in dealing with this condition.
Transcatheter Aortic Valve Replacement (TAVR), first performed on a patient in 2002, has quickly progressed over the years. It’s now usually the first choice for treatment in many patients who suffer from aortic stenosis. Initially, TAVR was used on patients who faced high risks or prohibitive situations for performing the traditional Surgical Aortic Valve Replacement (SAVR), but its use has widened to include patients who are at intermediate and low risk as well.
Throughout its evolution, TAVR has faced various challenges and has undergone various technical changes that have made it safer and more effective. Landmark medical studies like the PARTNER 1 and PARTNER 2 have shown the benefits of TAVR when compared to traditional medical management methods and SAVR. Here, we provide a simple explanation of the TAVR procedure for aortic valve stenosis.
Anatomy and Physiology of Catheter Management of Aortic Valve Disorders
The aortic valve is a part of your heart that acts like a doorway between your heart’s main pumping chamber (the left ventricle) and the main artery that supplies oxygen-rich blood to your body (the aorta). Most commonly, the aortic valve has three small flaps or leaflets that open and close with each heartbeat. These three leaflets are named the left coronary leaflet, the right coronary leaflet, and the non-coronary leaflet.
The aortic valve is attached to a strong tissue base which is connected with a part of your heart called the fibrous skeleton. This structure helps keep all the parts of the heart in the right place. In some patients, however, the aortic valve may only have two leaflets; this is known as a bicuspid aortic valve. The heart’s electrical system, which controls the rhythm of your heartbeats, typically runs underneath one of the leaflets of the aortic valve.
Why do People Need Catheter Management of Aortic Valve Disorders
Current guidelines suggest the Transcatheter Aortic Valve Replacement (TAVR) procedure for patients who are at intermediate to high risk of complications during surgery and have a severe condition known as aortic stenosis. This condition occurs when the heart’s aortic valve narrows, restricting blood flow to the rest of the body. TAVR is also recommended when a previously placed artificial heart valve fails to function properly.
In 2019, the U.S. Food and Drug Administration (FDA) approved TAVR for patients at low risk of complications during surgery. However, the official guidelines have yet to include these patients. In such cases, a procedure called Surgical Aortic Valve Replacement (SAVR) might be recommended if the patient can safely undergo surgery. Currently, TAVR is not approved for patients whose aortic valves do not close properly (a condition known as aortic valve insufficiency). However, a number of studies are challenging this guideline.
The Balloon Aortic Valvuloplasty (BAV) was introduced in 1986 as a non-invasive option to treat aortic stenosis. But because of a high failure rate and poor long-term survival rates, it is rarely performed today. Instead, it is usually offered as a temporary treatment for patients not suitable for TAVR or SAVR. Sometimes, it is used to help stabilize patients in critical condition until they can receive the TAVR or SAVR treatment. BAV is often carried out to aid with valve implantation during a TAVR operation.
When a Person Should Avoid Catheter Management of Aortic Valve Disorders
There are times when performing TAVR (Transcatheter Aortic Valve Replacement), a type of heart valve replacement procedure, isn’t advisable. These may include:
If a patient isn’t expected to live for more than a year, TAVR isn’t generally recommended. Similarly, if there isn’t a team of heart specialists available, or if there’s no back-up heart surgery unit on-site, TAVR might not be a suitable option.
Other health conditions might also prevent TAVR procedures. These could include severe memory problems (known as profound dementia), or if a patient has had a heart attack in the last month. Lung diseases, such as severe pulmonary hypertension with right ventricular dysfunction, and drastically reduced left ventricular function (less than 20% ejection fraction) may also be a factor.
There’s also a need to consider the size of the original aortic valve opening (called the native aortic annulus). If it’s too small (less than 18mm) or too big (more than 25mm), TAVR may not be a good option. TAVR may also be unsuitable if a person has a growth, clot, or infection inside their heart (an intracardiac mass, thrombus, or vegetation), if certain parts of the heart make successful catheterization difficult, or if there is severe mitral regurgitation or insufficiency causing leaking of a heart valve.
The patient’s capability to undergo anticoagulation or blood-thinning treatment, undergoing dialysis, high levels of creatinine in the blood (above 3 mg/dL), having a unique aortic valve (being bicuspid, unicuspid, or noncalcified), issues with the heart muscle (hypertrophic cardiomyopathy or HOCM), significant aortic disease, or mixed aortic valve disease also need consideration. One must also reconsider TAVR if a patient has had a stroke or transient ischemic attacks (TIA) within six months before the intended procedure.
As for BAV (Balloon Aortic Valvuloplasty), there are situations where it’s not advisable. These include conditions such as moderate to severe aortic insufficiency or leakage, presence of a growth inside the heart, active endocarditis (an inflammation of the heart valves), or if the patient can’t receive anti-thrombolytic therapy (treatment to break up blood clots) during the surrounding period of the operation.
Equipment used for Catheter Management of Aortic Valve Disorders
TAVR, or Transcatheter Aortic Valve Replacement, is a procedure that can be done in two types of rooms: a hybrid operating room or a cath lab. A hybrid operating room is a surgical theatre that is equipped with advanced medical imaging devices, while a cath lab is a special hospital room where doctors perform minimally invasive procedures that involve tubes, known as catheters, inserted into the body. This procedure uses a number of tools and instruments like wires, different-sized tubes for insertion, and surgical instruments suited specifically for it.
Similarly, the BAV, or Balloon Aortic Valvuloplasty, is often carried out in the cath lab. In this procedure, a doctor uses a balloon to widen a narrowed heart valve. They use modern imaging techniques, like fluoroscopy, which allows real-time X-ray images, or transesophageal echocardiography (TEE), which is an ultrasound test that gives clear pictures of the heart area. Everything is done according to the specific protocol of the hospital, ensuring everyone’s safety.
Who is needed to perform Catheter Management of Aortic Valve Disorders?
In the United States, a procedure known as TAVR (Transcatheter Aortic Valve Replacement) is performed by a team of medical professionals. The team is led by a cardiac surgeon and an interventional cardiologist, who work together during the procedure. A cardiac surgeon is a specialized doctor who operates on the heart, and an interventional cardiologist is a heart doctor who specializes in using thin, flexible tubes called catheters to provide treatment.
Aside from these doctors, other important team members include an anesthesiologist, preferably one specialized in heart procedures, who uses medicine to make sure you don’t feel pain during the procedure. There is also a perfusionist on standby, who is a medical professional trained to use the heart-lung machine during surgery if necessary. The overall team consists of support staff from the operating room or catheterization lab, including scrub technicians and nurses who aid in the procedure.
For a procedure called BAV (Balloon Aortic Valvuloplasty), the medical personnel required include a trained interventional cardiologist and appropriate catheterization lab staff. As with the TAVR procedure, the preferred anesthesiologist is one with TEE (Transesophageal Echocardiography) capability. TEE is a type of ultrasound test that uses sound waves to create high-quality pictures of the heart and its blood vessels.
Preparing for Catheter Management of Aortic Valve Disorders
Before undergoing a TAVR (Transcatheter Aortic Valve Replacement) procedure, a team of heart specialists, including those who perform heart procedures (interventional cardiologists) and heart surgeons, evaluate the patient. The team decides unanimously whether the TAVR procedure is better for the patient than another heart surgery called SAVR. They also do a detailed study of the patient’s heart condition, decide the size of the artificial heart valve and choose the best way to access the heart.
It’s important to perform various tests before surgery, including an echocardiogram (an ultrasound of the heart), an angiography (X-ray imaging of blood vessels), and a CT scan (detailed images of the heart made by computer). The purpose is to evaluate the severity of the heart valve disease, the shape of the valve and the associated structures, the size of the opening through which blood flows (annulus), the degree of heart valve hardening, the best way to access the heart (lower and upper limbs), and the functioning of other heart parts. The valve size is decided using specialized software programs to ensure accurate measurements.
Tests should also be performed to evaluate the kidneys and liver and to check the levels of hemoglobin, glucose, and blood types. If lung disease is suspected, a lung function test and a blood gas analysis could also be performed. A detailed evaluation of the patient’s airway is essential to prevent unexpected problems during surgery when the patient is under general anesthesia. It’s also crucial to review the patient’s current medications before the surgery.
The patients are guided to continue their medications just as they would before any other surgery. Some patients might already be taking medicines to prevent blood clots, such as aspirin and clopidogrel, or these might be started before the procedure. Each center may have different practices for using these medicines after the surgery. Around an hour before the procedure, antibiotics are given to prevent infections. Some centers might continue antibiotics after the surgery for three to seven days, although there is no standard rule for this.
Before a BAV (Balloon Aortic Valvuloplasty), a test (TTE) is done to check the severity and structure of the aortic valve (AV). The size of the aortic valve area and the force needed for blood to flow through the heart are also noted. A blood vessel imaging procedure (coronary angioplasty) is done to check for and treat any narrowed blood vessels.
How is Catheter Management of Aortic Valve Disorders performed
TAVR stands for Transcatheter Aortic Valve Replacement, a procedure used to replace a patient’s diseased aortic valve. The aortic valve controls the flow of blood out from your heart to the rest of your body. When it’s not working properly, a person may feel tired and short of breath. TAVR can be performed using different techniques and routes with the type of approach being chosen based on a number of factors, including the suitability of the patient’s blood vessels.
The most common route is through the large artery in your leg (transfemoral). But, if the arteries in the legs are too narrow or are not suitable, the procedure can be done through the large artery under your collarbone (transaxillary), through a small cut in the chest and through the point of your heart (transapical), through the aorta, the main blood vessel that supplies blood to your body (transaortic), or through the artery in your neck (transcarotid). The method that doctors choose to use depends on the specific situation of each patient.
In the transfemoral approach, doctors access the patient’s vessels either directly with a small cut in the skin or through a needle-prick in the skin. They then insert a wire through a small tube and navigate it to the aortic valve using special imaging equipment. The new valve is attached to this wire and pushed up and into position. Once in place, the new valve starts functioning immediately.
In the transaxillary approach, a similar procedure is followed but doctors initially make a small cut below the collarbone to access the blood vessel. Meanwhile, in the transapical method, the procedure is done through a small incision in the chest with the new valve moving in the same direction as the blood flow, therefore it requires placing the valve in the opposite orientation compared to the other methods. In the transaortic approach, doctors access the aorta through a small cut in the upper part of the breastbone.
A procedure called a balloon valvuloplasty (BAV) can also be done, either separately or as part of the TAVR procedure. This involves positioning a balloon catheter across the narrow aortic valve and inflating it. The goal is to expand the valve opening and improve the blood flow.
All of these procedures aim to provide a new working aortic valve for the patient to improve their symptoms and quality of life. Your doctor will advise on the best approach for you, taking into account the specifics of your individual situation.
Possible Complications of Catheter Management of Aortic Valve Disorders
After going through a procedure to correct a heart valve known as a Transcatheter Aortic Valve Replacement (TAVR), some people may experience complications. Studies have shown the most common serious complications could include problems with blood vessels, abnormal heart rhythms, or even strokes. Deaths, blockages of the heart’s main blood vessels, tears in the big blood vessel coming out of the heart, and major bleeding can also occur but are less common.
In patients who had a worn-out artificial heart valve replaced with a new one through TAVR, the chance of having blocked heart arteries was four times higher. Other possible complications could include a tightening or leaking heart valve, incorrectly placed valve, a device getting loose and traveling in the bloodstream, kidney disease, or a heart attack. Clinical trial results showed a higher rate of kidney disease when TAVR was used compared to traditional open-heart surgery (SAVR).
Using a balloon to open a narrow heart valve (BAV, balloon aortic valvuloplasty) doesn’t improve long-term survival. Therefore, it’s mainly used for temporary relief or as a first step towards TAVR or SAVR. Complications from BAV could include longer hospital stays, needing blood transfusions, acute kidney injury or failure, serious blood vessel problems, abnormally low blood pressure, fluid accumulation that interferes with heart function, needing a pacemaker, moderate to severe leaking heart valve, heart blood vessel blockage or tear, stroke, or death during the procedure.
What Else Should I Know About Catheter Management of Aortic Valve Disorders?
Transcatheter aortic valve replacement (TAVR) was a significant innovation in treating heart valve disease. It provided a new way to treat aortic valve disease, especially for those patients who are not suitable for the traditional Surgery method, known as Surgical Aortic Valve Replacement (SAVR). In simple terms, TAVR is a less invasive process and found to have less risk compared to traditional surgery.
On the other hand, balloon aortic valvuloplasty (BAV) was the first lesser invasive therapy/technique introduced for severe aortic valve disease treatment. However, it’s no longer used as the main treatment, except for providing some temporary relief. Although it’s not actively used, BAV paved the way for more impactful therapies like TAVR. Nowadays, BAV is still performed as a bridge treatment to support patients until they get either TAVR or SAVR. It also continues to be used for palliative care – care that aims to enhance the quality of life for patients with serious illnesses – as it hasn’t been proven to extend a patient’s life significantly after the procedure.
