Transcatheter Aortic Valve Repair (TAVR)
Aortic stenosis affects an estimated 1.5 million Americans and is the most commonly diagnosed heart valve condition. When blood leaves the heart, it flows through the aortic valve into the aorta, the main artery carrying blood out of the heart. In patients with aortic stenosis, the aortic valve does not open fully, which decreases blood flow from the heart and can lead to shortness of breath, dizziness, chest pain, and in some cases, sudden death.
The traditional treatment is an open aortic valve repair, open heart surgery that involves the patient being on a heart-lung machine. However, about one-third of those diagnosed with aortic stenosis are deemed inoperable or too high risk for the procedure due to other health conditions. Transcatheter aortic valve replacement (TAVR) offers a new option for these patients.
Baystate Medical Center in Springfield is currently the only hospital in western and central Massachusetts (outside of Boston) to offer the TAVR procedure. An interdisciplinary team from the Baystate Heart & Vascular Program including cardiac surgeons, cardiologists, cardiac anesthesiologists, and radiologists perform TAVR in the new Davis Family Heart & Vascular Center at Baystate.
How TAVR Works
In some respects, the TAVR procedure is similar to angioplasty. Under general anesthesia, a catheter is inserted into a blood vessel in the patient’s groin. A replacement valve (the Edwards Lifesciences’ SAPIEN Transcatheter Heart Valve is currently the only one with FDA approval for TAVR) is placed on a stent, which is advanced through the blood vessel and into the heart. Once it reaches the aortic valve, a balloon is inflated, pushing the calcification and the faulty valve against the aortic wall, making room for the new valve.
It’s not a true replacement valve, but an implanted valve inserted into the old valve. (With an open procedure, you actually take out the old valve and replace it with a new one.)
More recently, TAVR has also been approved for use with a transthoracic approach, using a small incision in the chest to access the aortic valve, which further opens up the procedure to patients who also have blood vessel diseases in the leg that would prohibit the catheter approach.
|Illustration A: The replacement valve is placed on a stent, which is advanced through the blood vessel and into the heart.
||llustration B: The balloon of the delivery system carrying the valve is inflated, expanding the new valve within the diseased valve. During valve expansion, the heart is stabilized by temporarily speeding up the heartbeat. The new valve pushes the leaflets of the diseased valve aside.
(Illustrations courtesy of Edwards LifeSciences)
Why Physicians Use TAVR
As the gateway to the aorta, a normal aortic valve consists of three tightly-fitting, triangle-shaped leaflets that operate like a one-way gate. When the left ventricle constricts, the valve opens and blood flows into the aorta. Then the left ventricle relaxes and the valve closes to prevent blood from flowing back into the ventricle.
Aortic valve stenosis prevents the valve from fully opening. It is most commonly caused by the age-related, progressive calcification of a normal, three-leafed aortic valve. Other causes include calcification of a congenital bicuspid (two-leafed) aortic valve, or previous rheumatic fever, which can cause scar tissue that damages the valve. Patients with symptomatic aortic valve stenosis (mild/moderate stenosis often does not cause symptoms) may suffer from shortness of breath on exertion, syncope, chest pain, and, in some cases, sudden death.
While some patients can be treated with medications, these medications cannot reverse damage to the heart valve. An open aortic valve repair has been the standard of care for symptomatic, severe aortic valve stenosis for decades, but it is not an option for a growing number of patients deemed too high a risk for open-heart surgery, typically because of aortic calcification, underlying lung disease, or frailty. Essentially, TAVR allows surgeons to treat a very high risk group of patients who would otherwise not be candidates for surgery and making them ‘operable’ by using a technique with less risk.
Benefits & Risks
TAVR has many benefits for patients, including a quicker recovery, and outcomes for the procedure are superior in inoperable patients compared to medical therapy alone. In the multi-center PARTNER (Placement of AoRtic TraNscathetER Valves) trial, TAVR offered significant survival benefit in inoperable patients compared to medical therapy alone at one year. 69% of patients undergoing TAVR were alive one year after implantation of a new valve, while only 49% of medically treated patients were alive.
In the same trial, in the operable group, there was no difference in survival between TAVR and surgical valve replacement at the one year follow up (76 vs. 73%). TAVR does carry twice the risk of stroke as the open procedure in inoperable patients.