A Game Changer for Open Heart Surgery

Written by on June 4, 2012 in Research & Technology - No comments
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The Sapien valve is made of cow tissue and polyester and is immediately functional once in place.

By Taylor Arnold

With obesity levels and type II diabetes on the rise in America, it comes as no surprise that more and more patients are battling a range of cardiovascular issues. And while the best remedy is often a healthy diet and regular exercise regimen, there are some cases where this simply isn’t enough. When patients don’t respond to beta-blockers or blood-thinning medications, or worse, when they have other high-risk conditions that won’t allow for open heart surgery, their options grow limited. Fortunately a number of technological advances are keeping the country’s top cardiologists on the cutting edge of heart health, and more importantly, helping patients avoid the operating table.

The Sapien valve

In November of 2011, The United States Food and Drug Administration (FDA) approved a new transcatheter heart valve that is expected to revolutionize the treatment of cardiovascular issues. The device – called the Sapien valve – offers a new, non-surgical option for individuals experiencing failing aortic valves. With this approach, doctors create a small incision in the groin or chest wall, and then feed the wire-mesh valve through a catheter and guide it up to the heart. The valve is then wedged into the aortic opening by an inflatable balloon, replacing the natural heart valve. This way, they can avoid opening the chest or stopping the heart.

“The impact of the Sapien valve is huge,” says Vinod H. Thourani, MD, Associate Professor of Cardiothoracic Surgery at Emory University School of Medicine in Atlanta, Ga. “It’s allowed us to take care of patients we couldn’t otherwise take care of. For the high-risk patient population, it provides a much easier route.”

This high-risk patient population includes approximately 300,000 Americans who currently suffer from deterioration of the aortic valve, the gateway to the heart. This condition forces the heart to work harder to pump blood, often leading to heart failure, blood clots and sudden death. The result is aortic stenosis, and according to the FDA, more than half of patients diagnosed with the condition die within two years.

Each year, about 50,000 people in the U.S. will undergo open-heart surgery to replace this valve, but the procedure is anything but easy. The surgeon must saw the breastbone in half, stop the heart, cut out the old valve and sew a new one into place. And until last year, thousands of other patients were turned away, deemed too old or ill to survive the operation. But thanks to the Sapien valve, more of this high-risk patient population can avoid going under the knife. The tiny cardiac device, manufactured by Edwards Lifesciences in Irvine, Cali., is made from cow tissue and polyester supported by a steel frame. Once surgeons put the Sapien valve in place, it is immediately functional.

The learning curve of transcatheter aortic valve replacement

Today Thourani performs multiple valve procedures a week, ranging from transcatheter aortic valve replacement (TAVR) to surgical aortic valve replacement (SAVR). But he admits there was a learning curve with the transcatheter valve, which he has been under study at Emory since 2007. “At first it was a novel procedure, and we were doing about two a month,” he explains. “Now we do about five to six procedures a week because our team can handle different patients in a more uniform fashion. It is operator dependent, so of course those who have done it more have more experience with it.”

The results of this extensive study at Emory, as well as the Partner I trial in 2007 led by Thourani and his team, were instrumental in the FDA’s approval of the Sapien valve in late 2011. To date, the Emory Heart & Vascular Center team have completed over 260 TAVR procedures, and while the Sapien device is currently only approved for patients who cannot undergo open-heart surgery, about 20,000 new patients in the U.S. should be eligible to receive a heart valve each year moving forward.

The FDA is expected to clear the Sapien valve for patients who are healthy enough to undergo surgery, but still fall under the high-risk population. Once this group is cleared, anywhere from 50,000 to 80,000 new patients will be eligible for the procedure each year in the U.S.

The safety of a TAVR procedure

Thourani has found the safety of a TAVR procedure to be the same as open surgery, although TAVR patients recover much faster. In fact, it’s not uncommon to go home two to three days after surgery. “Inoperative patients for SAVR are good candidates for TAVR,” he says. “They’re super high-risk based on objective patient characteristics such as previous operations, lung issues, severe chronic obstructive pulmonary disease (COPD) and poor heart function.”

When compared to open heart surgery, the most significant benefit of minimally invasive procedures is avoiding the risks and complications associated with the heart and lung bypass machine. Less invasive procedures also have a significantly shorter recovery time and require a shorter hospital stay. And in some cases, patients who were once considered to be too sick to be placed on a ventilator or undergo surgery are given another chance.

Nevertheless, the Sapien valve does not come without risks. According to the FDA, the approval of the device comes on the heels of a study based on a 365 patients who were not eligible for open-heart surgery. Half of these patients received the Sapien valve, while the other half received an alternative non-surgical treatment. Patients receiving the Sapien valve experienced two and a half times more strokes and eight times as many vascular and bleeding complications than patients who did not receive the implant, however, they were more likely to survive one year after surgery. After a year, 69 percent of the Sapien patients were alive compared with 50 percent of those who received an alternative treatment.

The future of valve procedures

As they continue to evaluate the safety of the Sapien valve, Thourani and the Emory team have enrolled patients in the Partner II trial. The goal was to examine the “next-generation” transcatheter aortic valve in patients with moderate surgical risk, and in early 2012, Thourani presented the results along with Emory cardiologist Dr. Vasilis Babaliaros. “It’s what we found with the original Partner trial, in that most of the discrepancies equaled out after a year,” Thourani says. “There are certain advantages with minimally invasive or endovascular-based therapy in high-risk patients, such as not having to open the chest and faster patient recovery.”

Emory Healthcare has also partnered with St. Joseph’s Hospital in Atlanta so that referring physicians can have more research options for their high-risk patient population. In light of this partnership, St. Joseph’s is currently participating in a clinical trial of the Medtronic CoreValve System, an alternative transcatheter aortic valve to treat patients with aortic stenosis. This valve is available in four sizes so that it may treat patients with diseased valves up to 31 millimeters in diameter.

The CoreValve System has the same objective as the Sapien valve, just a slightly different design. But until it is approved by the FDA, the CoreValve System is only available to patients enrolled in the study.

In addition to advances with the transcatheter heart valve, Thourani is working on a new procedure for patients with mitral valve diseases.
“This is specifically for patients with a closed up aortic valve,” he says. “Another area we’re working on is aortic leakage and aortic stenosis and other valve innovations surrounding the mitral valve. It’s available now, but in trials. I’m hoping it will be available in next five years.”

Ultimately he hopes to continue developing innovative strategies to improve the practice of minimally invasive valve surgery. “For the high-risk population, we can provide them an easier route,” he says. “The more we know, the easier it is to give a balanced approach to helping patients.”

Photos Courtesy of Edwards Lifesciences

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