TAVI, also known as transcatheter aortic valve implantation, is a minimally-invasive procedure that replaces a damaged aortic valve that doesn’t open and close fully during blood flow with an artificial healthy valve.
TAVI is a shorter procedure compared to open heart surgery, typically taking 1-2 hours for the entire valve implantation with quicker recovery time. Additionally, it only requires a mild sedative or general anesthesia for the procedure.
In the rapidly evolving technological world, advances in the current techniques are arising every day to ease the life of mankind, reduce risks and side effects of ongoing procedures, and enhance patient compliance and outcomes.
In this blog, we will discuss the latest advances in TAVI technology and techniques, their benefits, and how they are proving to be beneficial for patients.
Transcatheter aortic valve implantation (TAVI) is increasingly being performed worldwide as an alternative to surgical aortic valve replacement (SAVR) because of its minimally-invasive nature and as a substitute for patients with advanced age and surgical risks who could not benefit from SAVR.
Moreover, the indications for transcatheter aortic valve replacement are gradually extending to low-risk or young patients.
However, a few complications have been seen with the TAVI procedure, like aortic valve rupture, coronary artery blockage, and thrombus (blood clot) formation. Although these complications have a low incidence, if they occur can be fatal.
Here are some of the latest advancements in the TAVI procedure that reduce the risks and complications of transcatheter aortic valve implantation.
One of the advancements in the TAVI procedure that decrease the risks of procedural complications is the reduction of the catheter or valve size. Recent developments have reduced the artificial implant size to up to 14 Fr.
The catheter is an attached small hollow tube at the end of the implant that is used to deliver the artificial valve in place of the diseased valve. The implant helps correct or tighten the leaky aortic valve.
Reducing the implant size is a useful approach to prevent rupture or damage to the arteries present in the heart. Catheter-based artificial aortic valves with a reduced size approved for clinical use by the FDA include:
● SAPIEN 3
● LOTUS™
● ACURATE neoTM
SAPIEN 3
SAPIEN 3 is an artificially-designed transcatheter heart valve with a reduced diameter (14 Fr) and is used to fix aortic valve regurgitation. It is made of three leaflets (flaps) that are incorporated into the structure of cobalt chrome.
The valve cell structure is further enclosed in an open upper cell and closed lower cell with an added external seal. The seal is designed to prevent a condition known as a paravalvular leak (PAR) that generates a space between the healthy heart tissue and the replacing valve. The benefits of the SAPIEN 3 valve include:
LOTUS™
LOTUS™ is an artificial tricuspid valve enclosed in a sealed nitinol frame. It offers the lowest risks of paravalvular leaks and can be recovered or repositioned even after the entire valve implantation has been done. However, a downside of this valve is that it may cause conduction abnormalities, which requires a pacemaker in 30% of patients.
New generation LOTUS™, like LOTUS EdgeTM, are being developed and researched in clinical trials that have lower risks of conduction abnormalities.
ACURATE neoTM
Unlike LOTUS™, you cannot restore ACURATE neoTM valve after implantation, but it is designed to be largely stable during and after insertion. It is made of three structures that support and stabilize the valve in place, preventing leakiness and complications, including arches for axis alignment, an upper fixture for positioning, and an open lower body for support.
Previously, Transapical routes were used for the implantation of artificial valves. Transapical routes require relatively large incisions in the chest for valve implantation, which can reduce patient compliance.
Now, transfemoral has become the most preferred access route for the insertion of artificial valves. It requires a smaller incision made in the legs, which threads the valve up to the heart.
Another complication associated with transcatheter aortic valve implantation, which is low, i.e., less than 1% is coronary obstruction.
The blockage of coronary arteries may occur because the artificial valve insertion to the heart may displace the position of the coronary artery leaflets, leading to obstruction. Other reasons that might cause coronary obstruction from TAVI are calcified (hardened) valves or large-sized valves.
In patients with a high risk of coronary obstruction, a stent may be inserted in advance before the implantation of the aortic valve to prevent blockage of the coronary artery.
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