For whatever purpose you are searching for information about transcatheter aortic valve replacement or implantation, you have come to the right place. We aim to shed some light to this medical procedure that was once considered a miracle treatment.
Transcatheter aortic valve replacement is a process also known as TAVR or TAVI and it has revolutionized the treatment of calcific aortic stenosis. This procedure has enabled doctors and surgeons to replace dysfunctional aortic valve of the human heart using a minimally invasive method that does not require a large incision or the use of cardiopulmonary bypass.
Cases of severe symptomatic aortic stenosis used to carry a poor prognosis. Recently medical and technological advancements have allowed the resurgence of alternative treatment to such heart disease. The risks associated with surgical aortic valve replacement are threatening elderly patients, as well as patients with concomitant severe systolic heart failure or coronary artery disease. Transcatheter aortic valve replacement was developed as a solution to the risks posed by SAVR in treating aortic stenosis especially for the high-risk population.
Are you suffering from aortic valve stenosis? Or are you just eager to know more? Read on and don’t forget to post your comments in the section below.
Heart disease is one of the leading cause of death worldwide. According to recent statistics, there are around five million Americans who suffer from heart valve disease presently. The heart valve problems suffered by millions include a single faulty valve to four defective heart valves. Two years after the onset of the symptoms of heart valve problems, approximately fifty percent of patients die.
In the US, calcium build up is the number one cause of aortic valve stenosis. Doctors evaluate a patient’s heart through an echocardiogram or echo for short, the primary imaging test used to diagnose aortic valve stenosis.
Presently, the medical communities consider aortic valve replacement as the most effective treatment to AS. Transcatheter Aortic Valve Replacement was deemed a medical breakthrough a decade ago.
It is still considered one of the best options a patient with aortic valve stenosis can choose to undergo. TAVR does not entail open heart surgery and is basically a minimally invasive procedure wherein the defective or narrowed heart valve is replaced.
The condition wherein a patient’s heart valve does not open or close properly is called aortic valve stenosis and TAVR is an option for patients who are not fit to undergo open-heart surgery. It is an option as well for people who are identified as high-risk patients because of the complications of surgical aortic valve implantation.
A group of medical and surgical heart specialists will decide if the patient should undergo TAVR. The decision is made after consultations with the patient and after the multi-discipline team of heart specialists have identified TAVR as the best treatment. TAVR alleviates the symptoms and dangers posed by aortic valve stenosis. It can also improve the chances of survival of patients who are unfit for open-heart surgery.
Aortic Valve Stenosis
The narrowing of the aortic valve is a heart condition called aortic valve stenosis. This medical condition affects adults, but can also be seen in children and infants. Aortic valve stenosis is a condition that can range from mild to severe. If diagnosed with this condition, it means a valve of your heart is not opening properly to allow blood to pass through it in a single flow direction. Here are some of its symptoms:
- Pain and tightness in the chest
- Fainting after exertion
- Shortness of breath
- Palpitation and rapid, fluttering heartbeat
- Heart murmur
In most cases, patients fail to recognize the symptoms and are only diagnosed during a routine physical check-up when the doctor hears an abnormal heart sound or murmur. Only when the case is severe do these symptoms present themselves. Which is why, if you are already experiencing the signs listed above, it is imperative to see a doctor right away.
If you are wondering what causes aortic valve stenosis, there are conditions that can lead up to this such as:
- A patient with a congenital heart defect is more susceptible to aortic stenosis.A congenital deformity in the heart can cause aortic stenosis. In most cases, the child will not experience any of the symptoms until they have grown older and the valves begin to narrow. They can either leak or block blood flow to the heart. A child with a congenitally abnormal aortic valve needs a doctor to evaluate the valve and identify any problems so future complications can be avoided.
- Patients with a calcium buildup in the aortic valve. The cusps of the aortic valve can sometimes accumulate calcium deposits. This condition is called aortic valve calcification and can lead to stenosis. Since calcium is a mineral found in our blood, deposits of which can end up forming in the valve and result in stiffening of the cusps. This occurrence where an aortic valve and its stiff cusps cause narrowing of the blood’s passageway, happens to both children and adults, including some infants, the but more common in men aged 60 and above and women older aged 70 and above.
- Patients with rheumatic fever develop aortic valve stenosis.Strep throat infection and rheumatic fever can cause a scar tissue to form in the valve. The tissue can narrow the aortic valve and create a rough surface that accumulates calcium.
- In other cases, rheumatic fever can damage the heart valve and affect its closing and opening.
Calcification of the valves can be seen in patients who have taken large dosages of calcium supplements. Smoking and inhaling second hand smoke, living a reckless lifestyle including lack of sleep, disregarding the importance of a balanced meal, eating too many fat and ‘junk food’ are also culprits to blame and avoid.
How the Heart Works
The human heart has four chambers, two upper chambers called the atria and two lower chambers called the ventricles. The atria receives or is the passage through which blood flows in and the ventricles pump out blood.
The right ventricle pumps blood into your lungs for oxygenation and blood returns to pass through the heart from the lungs from to the left. The left ventricle is often referred to as the main pump because is where blood passes and is forced through the aortic valve. The aortic valve on the other is the largest artery in the human body.
The heart valves open and close and allow blood to flow in only one direction through the heart. A person whose heart valves do not open or close fully or properly is diagnosed with AS. The patient with a defective heart valve can end up having the blood flow from the heart to leak backward and disrupt the natural direction of the flow. The backward flow is called regurgitation.
Treating Aortic Valve Stenosis
The most effective way to treat the narrowing of the aortic valve is to remove the faulty valve and replace it with a fully functional one to open up the passage for blood to flow properly.
Contrary to popular notions, surgery isn’t recommended right away by doctors and specialists. Especially in case where the patient is only suffering from mild to moderate aortic valve stenosis with no symptoms, a regular check up will be required first to schedule the surgery at the most appropriate time. The patient will have to undergo a echocardiogram to confirm the AS, then the doctor will review the patient’s medical history for conditions that may affect the success of the procedure and consult a team of heart specialists. When it is agreed upon that the patient needs and is qualified to become a candidate of TAVR, the patient will be briefed with what to expect when the condition progresses without treatment and what the patient can expect after TAVR.
Surgery and/or transcatheter aortic valve replacement are necessary in addressing moderate and extreme narrowing of the aortic valve and doctors may order this even if the patient isn’t experiencing the symptoms.
As of the moment, there are no available medication that can cure aortic valve stenosis. If a doctor prescribes some medicine, it will be for managing the symptoms experienced by patients, not to serve as a cure. Fluid accumulation is one of the effects of stenosis to the heart as well as rapid heart beat and high blood pressure. These symptoms can be resolved by medication.
How is TAVR performed?
The United States’ FDA or Food and Drug Administration approved of TAVR for appropriate patients with aortic valve stenosis. Transcatheter aortic valve replacement is a process that is similar to balloon angioplasty. Candidates will have their natural aortic valve replaced with a prosthetic valve made of metal or animal tissue.
The mechanical valves used as replacement for natural but dysfunctional valves are made from high grade or surgical grade metal that is more durable than the organic valve. This type of replacement valve also has its pros and cons. The most critical risk it involves is the tendency to accumulate blood clots forming on and near the metal valve. If such a case occurs, patients who received a metal replacement or mechanical valve will have to take an anticoagulant medication for life in order to prevent the blood clots.
Another type of replacement valve is made up of biological tissue. The tissue can either come from an animal or a deceased donor. Compared to having a metal valve inside of the body that comes with a lifetime maintenance drug to avoid blood clot, some patients receive replacement tissue valves. However, there is still a downside for this type of valve replacement because like the natural valve replaced, the tissue valve can also narrow after years and will eventually require another replacement procedure.
The patient’s own pulmonary valve can serve as a replacement Another type of tissue valve replacement that uses your own pulmonary valve. The process is called autograft and it also has its own risk and benefits.
The doctor in charge should consult the patient and make them aware of the risk and benefits of all the procedures to replace a faulty heart valve listed above.
Transcatheter Aortic Valve Replacement Contraidications
The exclusion criteria followed by medical institutions as contraindications to TAVR are:
- If patient has evidence of acute myocardial infraction or M1, 30 days or less before the procedure is scheduled.
- Patients with non-calcified aortic valve with a congenital uni-cuspid or congenital bicuspid valve.
- Patients with mixed aortic valve disease such as aortic stenosis and prominent aortic regurgitation.
- Patients with respiratory instability who need inotropic support, mechanical ventilation, or mechanical heart assistance.
- Patients who need emergency surgery for any other reason.
- Patients with hyperthrophic cardiomyopathy.
- Patients with severe left ventricular dysfunction. Including those with a left ventricular ejection fraction or LVEF of less than 20%.
- Patients with severe pulmonary hypertension and right ventricular dysfunction.
- Patients who have intracardiac mass, thrombus or vegetation that can be found during echocardiographic examination.
- Patients with hypersensitivity to all anticoagulation regimens and patients with an inability to undergo anticoagulation.
- Patients with native aortic annulus smaller than 18 mm or larger than 25 mm.
- Patients who have experienced MRI-confirmed stroke or transient ischemic attack within 6 months (180 days) of the procedure.
- Patients who have renal insufficiency or a creatinine level >3 mg/dL, and/or end-stage renal disease that requires chronic dialysis at the time of screening.
- Patients with an estimated life expectancy of less than 12 months or less than 365 days because of non-cardiac comorbid conditions.
- Patients with severe incapacitating dementia.
- Patients with significant aortic disease, including
- Abdominal aortic or thoracic aneurysm
- Aortic arch atheroma especially if thicker than 5 mm protruding or ulcerated
- Narrowing especially with calcification and surface irregularities of the abdominal or thoracic aorta
- Severe tortuosity of the thoracic aorta
- Severe mitral regurgitation.
Not all patients can choose from the medical procedures listed above. With complications and other health conditions, some patients are not fit for surgery and especially not the open-heart procedure.
Patients who undergo TAVR have been briefed by their doctors that this is the best remedy for aortic valve stenosis for their particular case. In case you are wondering why the patient should undergo TAVR, the doctor will probably explain that it is less risky than open-heart surgery, but is still an effective solution.
Patients who are not fit for surgical replacement of the aortic valve can forgo having a large incision on their chests and choose to have the new replacement valve implanted through a small incision in the leg. Or through a smaller incision in the chest.
As an alternative procedure, transcatheter aortic-valve replacement is accepted in the medical communities all over the world. Although less is known when it comes to the outcome comparison among patients with severe aortic stenosis who had surgical valve replacement versus TAVR. The point, however, remains – patients with severe aortic stenosis who are considered high surgical risk, could opt for TAVR instead of surgery.
The New England Journal of Medicine published the results of the study known as PARTNER 2. The study was conducted a 57 sites and involved 2032 patients with an average age of 81, considered intermediate risk for surgery, suffering from severe aortic stenosis. The study presented data that the TAVR patients actually were in better shape than surgery patients at 30 days after the procedure. In the two year mark, there was no difference in outcomes. The primary end point was death from any cause of disabling stroke at two years.
The researchers responsible for the PARTNER1 study hypothesized that TAVR would at least be non-inferior to surgery. 76.3% of the respondents were candidates for transfemoral TAVR while the rest of the patients were eligible only for transthoracic access. The researchers used Bayesian analytical methods with a margin of 0.07, in order to evaluate the non-inferiority of TAVR as compared with surgical valve replacement.
The result after two years, 21.1% death or disabling due to stroke for surgery patients and only 19.3% for the TAVR patients. It should also be noted that the trans-thorocic patients and surgery patients had the same outcome. The better results came from the transfemoral group. Overall, the study was able to present data that the rates for death and serious stroke were better than what the researchers had anticipated.
At the time the study was being conducted, TAVR already became a popular approach to aortic valve stenosis. Most patients who have undergone the treatment chose TAVG because of the speedy recovery. Allow us to quote Partner 2 conclusion, TAVR was a noninferior alternative to surgery in patients with severe aortic stenosis at intermediate surgical risk, with a different pattern of adverse events associated with each procedure
The Success of Transcatheter Aortic Valve Replacement
While Partner 1 and 2 studies presented data that proved the transfemoral TAVR as the more effective approach to AS, there are still questions regarding the success of TAVG in general – if the transcatheter aortic valve replacement procedure the better choice to treat AS. There are some issues regarding post-TAVR expectations and its lifetime effects that often stem from the unrealistic promise that the procedure will work wonders on patients with AS and how some doctors fail to temper expectations of the patients and their loved ones.
Ever since it was first clinically performed on an AS patient back in 2002, transcatheter aortic valve implantation or transcatheter aortic valve replacement has been accepted as an established treatment of symptomatic severe aortic stenosis, particularly recommended for patients deemed too high risk for surgical aortic valve replacement.
So far, there have already been over 50,000 aortic valve implants performed in more than 40 countries all over the world. The number of clinical TAVR procedures have increased, meaning there are more and more data to be analyzed. With careful patient selection, systematic risk stratification, not to mention the meticulous procedural techniques – TAVR is a procedure that is here to stay and evolve to perfection. Yes, there are some issues to address before it can be more widely adopted, but the quality of life improvement and cost-effectiveness of this process when pitted against surgical aortic valve replacement seems to outweigh the concerns.
Transcatheter aortic valve replacement has expanded to valve-in-valve procedures that is its most promising and novel application. And with even more studies in this field of medicine, the process can be further refined and explored to safely and effectively address the needs of high risk patient population.