Here is potentially life-saving news for people with severe aortic stenosis, a narrowing or obstruction of the heart’s aortic valve (which connects the left ventricle of the heart to the body’s main artery). Many patients who have been told that they are too old or too sick to risk traditional valve-replacement surgery — despite having a poor prognosis without it — will soon be able to get that much-needed new valve with a safer, less invasive procedure called transcatheter heart valve-replacement surgery.

To learn more about this breakthrough, I called University of Western Ontario cardiac surgeon Michael Chu, MD, one of the pioneers of this technique. But before I convey the details on the new procedure — which is currently approved and available in Europe and under investigation in the US and Canada — let me cover some basics.

The heart has four valves. Each valve has flaplike doors called leaflets that open and close in a coordinated rhythm with every heartbeat. When the aortic valve develops stenosis — for instance, from a buildup of calcium deposits — it stiffens and narrows and its leaflets do not open far enough. Less blood is pumped through with each heartbeat, so the heart must work harder to pump normal amounts of blood. Over time, the heart muscle compensates by getting thicker… and eventually the heart begins to fail.

Early on, people with aortic stenosis may have no symptoms. But as the disease progresses, they experience shortness of breath, muscle weakness, chest pressure or pain, dizziness and/or loss of consciousness. Aortic stenosis can lead to congestive heart failure and, in some cases, to sudden cardiac death. Dietary and lifestyle changes, such as eating less salt and getting more aerobic exercise, may help manage some symptoms of aortic stenosis — but they cannot cure it. There are no medications to treat severe aortic stenosis.

When symptoms are severe and cardiac function declines, surgery is needed — and therein lies the problem for many patients. Dr. Chu told me that conventional aortic valve replacement is routinely performed in younger, low-risk patients with excellent results. However, for patients over age 75 or those with other health problems (such as a history of stroke, lung disease or kidney disease), conventional surgery can be very risky. Yet without a replacement valve, only about half of such patients survive for more than a year. The new procedure offers hope for high-risk patients who otherwise would not be candidates for surgery. By way of comparison…

Conventional valve-replacement surgery is open-heart surgery done under general anesthesia. The breastbone is cut open… the patient is put on a heart-lung bypass machine… and the heart is stopped while the new valve is put in place. The patient typically spends seven days in the hospital. Recovery takes about three months.

Transcatheter heart valve-replacement surgery also is done under general anesthesia or under a lighter form called sedation. The surgeon makes a small incision in the groin, then threads a catheter through the femoral artery and up to the heart. A balloon is fed through the catheter and then inflated to widen the constricted valve area. The new valve is pushed up the catheter and into the heart, then implanted within the old valve. The breastbone is not cut, and no heart-lung bypass is needed — because all the while, the heart keeps beating and supplying oxygenated blood to the body. The procedure typically requires a three-to-four-day hospital stay and a one-to-two-week recovery period.

With conventional valve surgery in these high-risk patients, stroke rates as high as 20% have been reported… and 10% to 15% of patients die within 30 days of the procedure, Dr. Chu said. By comparison, in a study of patients ineligible for the conventional surgery (average age in the early 80s) who instead had transcatheter surgery, only about 4% had a stroke… and 5% to 10% died within 30 days of the procedure. Long-term results for transcatheter surgery are not yet known, but early data is promising, Dr. Chu said.

More than 10,000 transcatheter heart valve replacements have been done worldwide. Dr. Chu estimates that the FDA will approve the procedure within five years. In the meantime, patients with severely stenotic heart valves may want to consider having the procedure done abroad… or joining one of the US clinical trials currently recruiting participants (visit http://ClinicalTrials.gov and type “aortic transcatheter” in the search box).