Aortic stenosis primarily affects older people and occurs at higher rates in men than in women. Aortic sclerosis, the calcification and thickening of aortic valve leaflets, is a precursor to aortic stenosis and, in industrialized countries, is seen in approximately 2 to 3 percent of persons older than age 65. This disease progression is associated with an approximately 50 percent increase in the risks for both death from cardiovascular causes and new myocardial infarction (heart attacks). Severe aortic stenosis affects approximately 300,000 people worldwide, of which 100,000 reside in the U.S. 

Causes & Symptoms
The most common cause of aortic stenosis is excessive wear on the aortic valve. This usually develops with age, but the process may be expedited in patients who are congenitally predisposed to disease.

Calcium buildup can also expedite the development of aortic stenosis by stiffening the valve and limiting movement. These calcium deposits, which originate from the blood’s calcium supply as it flows through the aorta, accumulate over many years and are thusly more common in elderly patients.

Rheumatic fever can also cause aortic stenosis by producing scar tissue on the aortic valve and forcing the aortic valve to narrow. Rheumatic fever, though rare in developed countries, arises from complications of scarlet fever or strep throat. Aortic stenosis can take years to manifest in patients who have had rheumatic fever. Symptoms of aortic stenosis include: 

The standard treatment for patients with severe aortic stenosis is aortic valve replacement (AVR). Two types of replacement valves, mechanical and biological, can be used in this procedure. The patient's age, other medical conditions, potential pregnancy and lifestyle are factors in the choice of replacement valve. Because AVR is an invasive surgical procedure, some patients are at high risk for surgery, or are altogether ineligible for surgery and are not appropriate candidates for AVR.

An alternative to AVR, transcatheter aortic valve replacement is currently approved for use in more than 40 countries worldwide, and is being evaluated in clinical trials for use in the United States. In this investigational procedure, a physician uses a catheter to deliver and implant a prosthetic valve in the heart. The valve is mounted on a catheter and the physician guides the catheter through the body via arteries (typically through an entry point in the leg) and then through the aorta. Once the diseased aortic valve is reached, the replacement valve is deployed and secured in place. In countries where this procedure is approved for commercial use (the device received CE Mark in Europe in 2007), this treatment is typically used for patients with severe aortic stenosis who are considered high-risk for surgery or not eligible for surgery.
_________________________________________________________

Fact Sheet: Medtronic CoreValve® Transcatheter Aortic Valve System
**NOT APPROVED FOR COMMERCIAL USE IN THE UNITED STATES**

The standard treatment for severe aortic stenosis is open-heart valve replacement surgery. Research shows that, left untreated, as many as 50 percent of aortic stenosis patients with severe symptoms may die within two years. A significant number of severe aortic stenosis patients are at high risk for open-heart surgery, and one-third are altogether ineligible for open-heart surgery.  The Medtronic CoreValve U.S. Clinical Trial will evaluate the safety and effectiveness of the CoreValve Transcatheter Aortic Valve System in these groups of patients.

_________________________________________________________

In the U.S. the Medtronic CoreValve System is currently under clinical investigation and is not approved by the U.S. Food & Drug Administration (FDA) for commercial use.

The Medtronic CoreValve System is a new technology designed to replace a diseased aortic heart valve percutaneously – meaning through the skin – without open heart surgery and without surgical removal of the diseased valve.

In the Medtronic CoreValve U.S. Clinical Trial, the replacement valve will be delivered primarily through a small opening in the femoral artery, threaded through arteries and across the aorta, and deployed in the native aortic valve. Once in place, the CoreValve is designed to take over the native valve’s function and ensure that oxygen-rich blood flows into the aorta and circulates throughout the body.

The CoreValve System is sized at 18-French (less than 1/4 of an inch). It is made from porcine (pig) cardiac tissue fixed to a self-expanding, Nitinol frame and is delivered through the femoral artery by a catheter (long thin tube). The self-expanding frame is designed to help physicians control and accurately deploy the valve.

_________________________________________________________

The CoreValve System is not currently available for commercial use in the United States. In 2010, the FDA approved its Investigational Device Exemption (IDE) application and pivotal clinical trial protocol to begin evaluating the Medtronic CoreValve System for transcatheter aortic valve implantation.

The CoreValve System received Conformité Européenne (CE) Mark in 2007, and it has been implanted in patients in more than 35 countries outside the U.S. since then.

CLICK HERE for printer friendly version