science

Transcatheter aortic valve replacement

Transcatheter aortic valve replacement is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Transcatheter aortic valve replacement rather than just read about it. In short: Transcatheter aortic valve replacement (TAVR), or transcatheter aortic valve implantation (TAVI), is the implantation of a replacement for the aortic valve through the blood vessels and into the heart, without removing the native valve. TAVR is an alternative to surgical aortic valve replacement (SAVR), which requires open heart surgery.

Key takeaways

Transcatheter aortic valve replacement belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Transcatheter aortic valve replacement to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Transcatheter aortic valve replacement from memory before moving on to harder problems.

Reference excerpt

Transcatheter aortic valve replacement (TAVR), or transcatheter aortic valve implantation (TAVI), is the implantation of a replacement for the aortic valve through the blood vessels and into the heart, without removing the native valve. TAVR is an alternative to surgical aortic valve replacement (SAVR), which requires open heart surgery. TAVR procedure is used to treat severe aortic stenosis. The first TAVI was performed on 16 April 2002 by Alain Cribier. The implanted valve is delivered via one of several access methods: transfemoral (in the upper leg), transapical (through the wall of the heart), subclavian (beneath the collar bone), direct aortic (through a minimally invasive surgical incision into the aorta), and transcaval (from a temporary hole in the aorta near the navel through a vein in the upper leg), among others. Severe symptomatic aortic stenosis carries a poor prognosis. At present, there is no treatment via medication, making the timing of aortic valve replacement the most important decision to make for these patients. Until recently, surgical aortic valve replacement was the standard treatment for adults with severe symptomatic aortic stenosis. However, the risks associated with surgical aortic valve replacement are increased in elderly patients and those with concomitant severe systolic heart failure or coronary artery disease, as well as in people with comorbidities such as cerebrovascular and peripheral arterial disease, chronic kidney disease, and chronic respiratory dysfunction.

Overview Patients with symptomatic severe aortic stenosis have a mortality rate of approximately 50% at 2 years without intervention. In patients who are deemed too high risk for open heart surgery, TAVI significantly reduces the rates of death and cardiac symptoms. Until about 2017 TAVI was not routinely recommended for low-risk patients in favor of aortic valve replacement, however it is increasingly being offered to intermediate risk patients, based on studies finding that it is not inferior to surgical aortic valve replacement. Transapical TAVI is reserved for patients for whom other approaches are not feasible: an evidence-based BMJ Rapid Recommendation made a strong recommendation against transapical TAVI in people who are also candidates for either transfemoral TAVI or surgery. People who have the option of either transfemoral TAVI or surgical replacement are likely to choose surgery if they are younger than 75 and transfemoral TAVI if they are older than 75. The rationale for age-based recommendations is that surgical aortic valve replacements are known to be durable long-term (average of durability of 20 years), so people with longer life expectancy would be at higher risk if TAVI durability is worse than surgery.

Devices Medtronic's CoreValve Transcatheter Aortic Valve is constructed of a self-expanding Nitinol (nickel titanium) frame and delivered through the femoral artery. This device received FDA approval in January 2014. Boston Scientific's Lotus Valve system was awarded CE mark approval in October 2013. It allows the final position to be assessed and evaluated before release and has been designed to minimise regurgitation. Boston Scientific has since retired the device as of January 11, 2021. This was primarily due to difficulty regarding the ability to reposition and recapture the valve. St Jude Medical's Portico Transcatheter aortic valve received European CE mark approval in December 2013. The valve is repositionable before release to ensure accurate placement helping to improve patient outcomes. Edwards' Sapien aortic valve is made from bovine pericardial tissue and is implanted via a catheter-based delivery system. It is approved by the FDA for use in the US.

Implantation The devices are implanted without open heart surgery. The valve delivery system is inserted in the body, the valve is positioned and then implanted inside the diseased aortic valve, and then the delivery system is removed. The catheter-based delivery system can be inserted into the body from one of several sites. Pre-procedural planning includes aortic valve annulus measurements and possible procedural complication likelihood. The standard for preoperative plans is to perform a multi-detector computed angiotomography (MDCT), which delivers the information required. Magnetic resonance imaging (MRI) and 3D echocardiography is an alternative.

Transfemoral approach The transfemoral approach requires the catheter and valve to be inserted via the femoral artery. Similar to coronary artery stenting procedures, this is accessed via a small incision in the groin, through which the delivery system is slowly fed along the artery to the correct position at the aortic valve. A larger incision in the groin may be required in some circumstances. The femoral artery (via transfemoral approach) is the traditional access for percutaneous aortic valve implantation.

Transapical approach The transapical approach sees the catheter and valve inserted through the tip of the heart and into the left ventricle. Under general anesthesia, a small surgical incision is made between the ribs, followed by a small puncture of the heart. The delivery system is then fed slowly to the correct position at the aortic valve. The puncture in the heart is then sutured shut.

Transaortic approach The transaortic approach sees the catheter and valve inserted through the top of the right chest. Under general anesthesia, a small surgical incision is made alongside the right upper breastbone, followed by a small puncture of the aorta. The delivery system is then fed slowly to the correct position at the aortic valve. The hole in the aorta is then sutured shut.

Transcaval approach The transcaval approach has been applied to a smaller number of patients who are not eligible for transfemoral, transapical, or transaortic approaches. In the transcaval approach a tube is inserted via the femoral vein instead of the femoral artery, and a small wire is used to cross from the inferior vena cava into the adjacent abdominal aorta. Once the wire is across, a large tube is used to place the transcatheter heart valve through the femoral vein and inferior vena cava into the aorta and from there the heart. This otherwise resembles the transfemoral approach. Afterwards, the hole in the aorta is closed with a self-collapsing nitinol device designed to close holes in the heart.

… excerpt ends here. Continue reading the full article.

Illustrations

Transcatheter aortic valve replacement illustration

Worked examples

Example 1 — a first encounter with Transcatheter aortic valve replacement

Start with the simplest possible case. Write down what Transcatheter aortic valve replacement claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Transcatheter aortic valve replacement before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Transcatheter aortic valve replacement ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Transcatheter aortic valve replacement

In research: Transcatheter aortic valve replacement appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Transcatheter aortic valve replacement in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Transcatheter aortic valve replacement is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cardiac procedures, so understanding it makes those chapters shorter.
In everyday life: Look for Transcatheter aortic valve replacement outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Transcatheter aortic valve replacement” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Transcatheter aortic valve replacement in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Transcatheter aortic valve replacement means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Transcatheter aortic valve replacement out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Transcatheter aortic valve replacement in simple terms?

Why does Transcatheter aortic valve replacement matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Transcatheter aortic valve replacement?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Transcatheter aortic valve replacement.