日前，美国食品药品管理局（FDA）批准了“无需开胸即可植入的人工主动脉瓣”，这一被专家们公认为“人工心脏瓣膜制造史上的突破”可以进一步扩大主动脉瓣膜置换的适应症，即可以让那些年老体弱之主动脉瓣功能不全的患者成功地接受手术，这无疑可以改善这类患者的生活质量和延长他或她们的生命。

主动脉瓣（aortic valve）是人的心脏拥有的四个瓣膜之一，它在心脏收缩过程中承受着最大的压力或负荷，常常随着年龄的增大而出现钙化，钙化后的主动脉瓣可出现狭窄和/或关闭不全，久而久之则可显著影响心脏的功能，故需要用人造瓣膜予以置换以改善心脏功能或防止其恶化。已往，外科医生为患者置换人工瓣膜需要经开胸手术才能够完成，如今被FDA批准应用于临床的新一代的人工主动脉瓣膜（The Sapien Transcatheter Heart Valve）可经导管由外周血管输送至主动脉根部，进而完成原本需要开胸的主动脉瓣置换术。更多资讯，请参阅原文。

FDA OKs Heart Valve That Does Not Require Open-Heart Surgery

Experts believe the device will expand options for frailer, sicker patients

THURSDAY, Nov. 3 (HealthDay News) -- The first artificial heart valve that can be implanted without open-heart surgery has been approved by the U.S. Food and Drug Administration.

The Sapien Transcatheter Heart Valve is designed to replace an aortic heart valve damaged by senile aortic valve stenosis, a progressive and age-related illness caused by calcium deposits that cause the valve to narrow.

One expert called the advent of the device "a revolutionary breakthrough" in terms of expanding access for sick or frail patients.

"This new approach to valve replacement is designed for the elderly and the highest risk patients who are inoperable -- or nearly inoperable -- by conventional criteria," said Dr. Gregory Crooke, assistant director of cardiothoracic surgery at Maimonides Medical Center in New York City, which is already offering the device to select patients. "As has been shown in trials, it should greatly improve the survival and quality of life for this cohort of patients," he said.

In aortic stenosis, the heart has to work harder to pump sufficient amounts of blood through the narrowed valve opening. This eventually causes the heart to weaken, leading to problems such as fainting, chest pain, heart failure, irregular heart rhythms, or cardiac arrest.

More than half of patients with symptoms of senile aortic valve stenosis die within two years. Open-heart surgery to replace the diseased valve can restore blood flow, but the procedure is too dangerous for some patients, the FDA noted in a news release.

The new artificial valve -- made of cow tissue and polyester supported with a stainless steel mesh -- provides an option for these patients. The valve is compressed into the end of a catheter that's inserted into a femoral artery (large artery in the thigh) and threaded to the site of the diseased valve. The artificial valve is then released from the catheter and expanded with a balloon. The valve is immediately functional, according to information in the FDA news release.

The FDA's approval of the valve is based on a study of 365 patients with the condition who weren't eligible for open-heart surgery. Half of the patients received the artificial valve while the other patients received alternative treatments, such as one that enlarges the aortic valve opening by stretching it with a balloon.

Patients who received the new valve did have eight times as many vascular and bleeding complications and 2.5 times more strokes than those who did not receive the valve. 　　However, patients who received the valve were also more likely to be alive one year after surgery than those who received an alternative treatment -- 69 percent versus 50 percent, respectively, the investigators found.

The most common serious side effects associated with the artificial valve and its implantation include death, stroke, perforation of blood vessels or ventricular or valvular structures in the heart, significant bleeding, leaks around the new valve, and damage to the heart's conduction system, which is responsible for a consistent and healthy heart beat.

Another cardiologist called the device's approval "important news."

"Often these patients are elderly with numerous other medical ailments that make standard aortic valve surgery too risky to perform," said Dr. James Slater, director of the Cardiac Catheterization Lab at NYU Langone Medical Center in New York City. 　"Medical [drug] therapy is generally not effective and the availability of a therapy that is less invasive and traumatic than standard surgery is an important advance," he added.

Slater also hopes that "further improvements in these devices will decrease the rate of complications and that further investigations will allow this therapy to be available to a wider range of patients with this disease."

California-based Edwards Lifescience, which makes the new valve, says it will continue to evaluate patient outcomes through a national registry.

The FDA approved the Sapien Transcatheter Heart Valve for patients who are not eligible for open-heart surgery, but it is not approved for those who can be treated by open-heart surgery. The agency also said that patients with congenital heart valve abnormalities, masses or an infection in their hearts, or those who cannot tolerate anticoagulation/antiplatelet therapy should not receive the new valve.

The valve's product label says a heart surgeon should be involved in determining if a patient is a suitable candidate for the artificial valve.

SOURCES: U.S. Food and Drug Administration, news release, Nov. 2, 2011; Gregory Crooke, MD, assistant director, cardiothoracic surgery, Maimonides Medical Center, New York City; James Slater, M.D., director, Cardiac Catheterization Lab, NYU Langone Medical Center, New York City