Posts Tagged ‘transcatheter valve implantation’

A Look at Transapical Aortic Valve Implantation

Transapical aortic valve implantation (AVI) is a minimally invasive technique that replaces the aortic valve through the placement of a small incision under the left breast—directly below the heart—without using cardiopulmonary bypass. It’s designed for patients who do not have appropriate sized femoral vessels in the groin for the treatment of aortic stenosis.

Transapical AVI is actually a type of transcatheter valve implantation. There are two ways to go about this sort of implantation: through transapical or transfemoral routes (a transfemoral procedure involves an incision in the groin area).

Transapical AVI is often referred to as an “off-pump” procedure, as routine surgical aortic valve replacement (AVR) requires that the breastbone be opened, and patients must be placed on a heart lung machine. Conversely, transapical AVI doesn’t involve opening the breastbone, nor does the procedure require utilization of the heart lung machine; hence the term “off-pump.”

So, why would a surgeon opt for transapical AVI, as opposed to transfemoral AVI? If a patient has too much calcium in their arteries or groin, this prevents us from being able to insert catheters in these areas, creating a case for transapical AVI.

Some of the typical candidates for this procedure include patients with severe aortic stenosis, or those who have blockage of the aortic valve. However, some patients do not qualify for this procedure, particularly for the purposes of the trial that Dr. Block mentioned in his last post. These include patients who are on dialysis, or who have had previous valve surgery. That said—we do anticipate that these parameters may change, potentially in late 2011.

Emory is truly a “one-stop-shop” in that we offer a multitude of services for the treatment of aortic stenosis: minimally invasive AVR, transcatheter AVI (transfemoral or transapical), off-pump left ventricle to descending aorta bypass, or balloon aortic valvuloplasty.  We are truly fortunate to be able to provide all of these services for our patients.

If you have any questions about transapical AVI or any of the numerous procedures we offer at Emory Heart & Vascular, please feel free to let me know in the comments section, or call me at 404-686-2513.

About Vinod H. Thourani, MD:

Dr. Thourani specializes in minimally invasive valve surgery (including mitral valve repair and replacement and aortic valve surgery) and transcatheter valve surgery (transfemoral and transapical aortic valve implantation).  He also performs other facets of adult cardiac surgery including on and off-pump coronary artery revascularization and atrial fibrillation surgery. He completed his general surgery residency, cardiothoracic residency, and cardiothoracic surgical research and clinical fellowships at Emory University.  Dr. Thourani joined Emory as a faculty member in 2005.

Transcatheter Valve Implantation Trial at Emory

The transcatheter heart valve is as large as 26 mm in diameter when expanded (left) and as small as 8 mm when collapsed over a balloon catheter (right).

In my last post, I focused on the definition, symptoms, diagnosis and treatment of aortic stenosis, a condition that can lead to heart failure. Sadly, aortic stenosis affects tens of thousands of Americans each year. In this post, I’d like to expand on one innovative treatment that is reducing the risks of this potentially fatal condition: transcatheter aortic valve implantation.

However, before we delve into an explanation of the treatment, let’s first review the specifics of the condition.

The aortic valve is the valve that connects the heart to the body, and is located between the left ventricle and the aorta. Blood flows through this valve, carrying oxygen to the rest of the body. There are typically three leaflets of tissue over the aortic valve that open and close and ensure proper blood flow. When the aortic valve becomes narrowed – either by degeneration or because is it abnormal from birth, the valve must be replaced to prevent heart failure.

Transcatheter aortic valve implantation is a new, innovative procedure used to replace the aortic valve. Rather than opening the chest and stopping the heart, we make a small incision in the groin or chest. We then insert a catheter (a thin, flexible tube) with a new aortic valve made of animal tissue through a blood vessel, using X-ray or ultrasound imaging to guide the device to the heart. As an alternative to open heart surgery, transcatheter aortic valve implantation has a substantially shorter recovery time and is particularly important for patients who are too weak to undergo the traditional process.

Emory has been involved in this groundbreaking technology since 2007, after Emory interventional cardiologist Vasilis Babaliaros, MD, helped bring the procedure back to us from France. The first cardiologist to perform transcatheter heart valve replacement was French doctor Alain Cribier, MD, who performed the procedure in 2002. Since 2007, we have completed approximately 85 transcatheter aortic valve implantations as part of a clinical trial, and we anticipate that the transcatheter valve will receive U.S. Food and Drug Administration (FDA) approval in late 2011. (You may view an animation video of the procedure here.)

Emory Heart & Vascular Center is proud to be one of the five largest centers in the United States and the most comprehensive in the Southeast to offer transcatheter aortic valve implantation. We are currently accepting patients for a new trial; for more information or to find out if you or someone you know may be a candidate for transcatheter aortic valve replacement, please contact me at 404-712-7667, or you may call Vinod Thourani, MD, at 404-686-2513. For other questions or comments on the procedure, I invite you to contribute in the comments section below.

What is Aortic Stenosis?

The word Aortic is derived from aorta, the main artery that pumps blood to the body from the heart. Additionally, the Greek translation of narrow is stenos.  In aortic stenosis, the aortic valve narrows, restricting blood flow from the heart to the body.

Most people are born with three leaflets of tissue over each artery that open and close as the heart beats. If someone is born with two leaflets, they may have premature narrowing of the valve. People with three valves often do not develop aortic stenosis until their 70s or 80s. Unfortunately, we can expect an increase in patients with aortic stenosis as baby boomers approach this age.

Common symptoms of aortic stenosis include:

–        Shortness of breath

–        Chest pain (often increasing with activity)

–        Fainting

–        Weakness

So, what is the science behind these symptoms? Simply put, as the aortic valve narrows, pressure increases inside the left heart ventricle. The left heart ventricle then becomes thicker, decreasing blood flow and causing chest pain. As the pressure continues to rise, blood may back up into the lungs, leading to shortness of breath. If you have a severe form of aortic stenosis, blood may not be able to reach your brain or other parts of your body as easily, causing fainting and weakness.

Typically, diagnosis starts with history-taking and a physical examination. We listen to the heart for a characteristic murmur that signifies a turbulent flow of blood across the narrow valve, and then perform an ultrasound to confirm the diagnosis.

For over 30 years, open heart surgery was the only way to treat aortic stenosis. Emory is the first hospital in the Southeast to study a non-surgical treatment called transcatheter aortic valve implantation.  It involves replacement of the narrow valve with a better-functioning synthetic valve from outside the body. We create a small incision in the groin or chest wall and then feed a wire mesh valve through a catheter, or tube, placing it where the new valve is needed. This technique may extend the lives of many people who are too ill or too frail to endure open-heart surgery.

In our next Heart and Vascular blog post, we’ll delve into more detail about procedures and technology surrounding aortic stenosis.

If you’re concerned that you may have aortic stenosis, we strongly encourage you to contact your physician for a physical. If you have further questions or comments regarding aortic stenosis or any other related condition, be sure to let me know in the comments section below.

Peter Block, MD has been practicing at Emory since 2000, where he specializes in internal medicine and cardiology. His areas of interests include angioplasty, cardiovascular disease, arteriosclerosis, and valve disease. Dr. Block’s major and/or recent publications focus on topics such as Equivalence Trials, Images in Clinical Medicine, and Short-Term Folic Acid Supplementation.