Transcatheter Aortic Valve Replacement (TAVR)
Learn about the basics of TAVR: a new and upcoming development on the structural heart side. A promising alternative to traditional aortic valve replacements for patients with mild aortic insufficiency.
CARDIAC SURGERIES
Avya Patel
10/7/20263 min read
What is a TAVR (Summary)?
A transcatheter aortic valve replacement is a novel procedure normally done by interventional cardiologists, structural heart doctors, or cardiac surgeons. A TAVR is the replacement of a narrowed, or stenosed aortic valve. Normally, a TAVR is done in high risk patients for open heart surgery (typically over 80 years of age). A TAVR is done, in summary, by a catheter placed in the neck or groin, then guided to the stenosed aortic valve by the descending or ascending aorta. Once at the valve, the TAVR is deployed by a balloon, and the old valve is pushed aside by a mesh-like framework.
TAVR statistics:
In the USA, the yearly average for TAVR is around 100,000 procedures with an average success rate being >95% with a lower stroke risk within the first 48 hours of the procedure.
Common risk factors for a TAVR are a stenosed aortic valve (indicated by symptoms such as chest pain, shortness of breath, and fatigue), patients over 65 years old especially if they have significant and prolonged symptoms from above.
Common comorbidities for a TAVR include hypertension, diabetes, anemia, chronic kidney disease, chronic obstructive pulmonary disease (COPD), and atrial fibrillation.
TAVR vs. Traditional aortic valve replacement:
TAVR:
Via the use of a minimally invasive catheter which then guides a collapsable valve in place of the stenosed aortic valve (the new valve is then expanded to push aside the damaged valve leaflets).
Risks:
Higher risk of needing a permanent pacemaker after the procedure (since TAVR often results in a Left-bundle-branch-block: LBBB).
Long term reliability remains in question
PVL (paravalvular leak) is common in some valve types
Benefits: Shorter hospital stay, shorter recovery time, lower risk of multisystem complications.
SAVR (surgical aortic valve replacement): Open heart surgery, heart is bypassed while surgeons remove the damaged valve entirely and place in the new valve.
Risks:
High intraoperative bleeding risk
Longer hospital stay and longer recovery time
Benefits:
Established procedure with long term durability
Lower rates of pacemaker needed when compared to TAVR
TAVR history and significance:
History of TAVR:
Animal trials for TAVR began in the 1980s with the first human trial/ procedure in 2002 by Dr. Alian Cribier on a 57 year old patient with a severly stenosed aortic valve (open heart surgery was not possible) and due to an ejection fraction (EF) of just 12%.
Evolution of TAVR: Over the last 15 years, TAVR has become the gold standard for inoperable patients that have a stenosed aortic valve.
The delivery systems for a TAVR have improved drastically, a 22-24 FR sheath size to a 14-16 sheath size improves groin and vascular access and reduces vascular complications in the surgery.
The implementation of a CoreValve-Evolut (self-inflatable and self-deployable) to SAPIEN (balloon inflatable) has improved hemodialysis and function.
The CoreValve-Evolute also has a range of sizes (23-34 mm) and uses/has external pericardial tissue to wrap around the valve and improve sealing the valve in place.
Significance of TAVR: Hallmark of minimally invasive cardiac procedures with implementation increasing over the past decade. Is best suitable for older patients who do not fare well for a SAVR, and allows for at least 10 years of longevity.
Preoperative care:
Before a transcatheter aortic valve replacement (TAVR), the patient undergoes a thorough evaluation to determine whether TAVR is appropriate and to plan the procedure. This typically includes an echocardiogram to assess the severity of aortic stenosis and heart function, a CT scan to evaluate the aortic valve and surrounding anatomy, and blood tests and other cardiac assessments. The medical team reviews the patient’s medications, allergies, medical history, and risk factors. The patient is usually instructed when to stop eating and drinking and whether certain medications, particularly blood thinners, need to be temporarily adjusted. The access site, usually the femoral artery in the groin, is also assessed and prepared.
Surgical procedure:
Upon sedation, catheter is placed in, normally, the femoral artery, in some cases, the subclavian artery or the carotid artery can be used. In the case the femoral artery is used, the valve is advanced through the descending aorta, through the aortic arch, until it is positioned within the diseased aortic valve. Once correctly positioned, the new valve is expanded, pushing the old valve leaflets aside and allowing the replacement valve. The team uses imaging such as fluoroscopy and echocardiography to confirm the valve's position and function before removing the catheter.
Image from WakeMed: https://www.wakemed.org/care-and-services/heart-vascular-care/cardiovascular-surgery/valve-conditions/tavr
Postoperative care:
After TAVR, the patient is closely monitored for complications and to make sure the new valve is functioning properly. Healthcare providers monitor heart rhythm, blood pressure, oxygen levels, the catheter insertion site, and signs of bleeding or infection. An ECG and follow-up echocardiogram may be performed to evaluate the new valve and detect problems such as abnormal heart rhythms, valve leakage, or conduction abnormalities. Patients are generally encouraged to begin moving around relatively soon after the procedure, depending on their condition, to reduce complications associated with prolonged bed rest. In some cased, LBBB (left bundle branch block) can occur after TAVR.
Before discharge, the medical team reviews medications, wound/access-site care, activity restrictions, and warning signs that require medical attention. Follow-up appointments are important for monitoring valve function and overall heart health. Patients may also be prescribed medications such as antiplatelet or anticoagulant therapy depending on their individual circumstances and other medical conditions.
