Transcatheter aortic-valve implantation (TAVI) is a new procedure in which a bioprosthetic valve is inserted through a catheter and implanted within the diseased native aortic valve. The Placement of AoRtic TraNscathetER valves (PARTNER) trial is a multicenter, randomized clinical trial comparing TAVI with standard therapy in high-risk patients with severe aortic stenosis. The co-principal investigators are Martin B. Leon, M.D., and Craig R. Smith, M.D., at NewYork-Presbyterian Hospital/Columbia University Medical Center. The data published today reflect a prespecified cohort of patients who were considered to be unsuitable candidates for surgery.
The primary end point was the rate of death from any cause over the duration of the study. A total of 358 patients with aortic stenosis who were considered to be unsuitable candidates for surgery underwent randomization at 21 centers, including 17 in the United States. Patients randomized for standard therapy received a combination of watchful waiting, medications, and balloon aortic valvuloplasty, which can provide transient clinical benefit but does not alter long-term outcomes.
At one year, based on the Hazard Ratio of 0.55, patients who underwent TAVI showed a reduction in mortality from 50.7 percent to 30.7 percent. In addition, there was a reduction in the combined endpoint of death from any cause or repeat hospitalization from 71.6 percent with standard therapy to 42.5 percent with TAVI. Among survivors at one year, the rate of cardiac symptoms was significantly lower among patients who had undergone TAVI, as compared with those who had received standard therapy (25.2 percent vs. 58.0 percent).
"Based on the reduction in mortality during the first year of the study, balloon-expandable TAVI should be the new standard of care in patients who are not suitable candidates for surgery," said Martin B. Leon, M.D., professor of medicine and director of the Center for Interventional Vascular Therapy at NewYork-Presbyterian Hospital and Columbia University Medical Center. Dr. Leon, founder and chairman emeritus of the Cardiovascular Research Foundation, is the co-principal investigator of the study.
At 30 days, TAVI, as compared with standard therapy, was associated with a higher incidence of major strokes (5.0 percent vs. 1.1 percent) and major vascular complications (16.2 percent vs. 1.1 percent). In the year after TAVI, patients had no deterioration in the functioning of the bioprosthetic valve, as assessed by evidence of stenosis or regurgitation on an echocardiogram.
"This study shows that transcatheter valve replacement is a safe and effective option for this life-threatening illness in patients unsuitable for surgical valve replacement," said Dr. Smith, study co-principal investigator and surgeon-in-chief at NewYork-Presbyterian Hospital/Columbia University Medical Center. Dr. Smith is also the Valentine Mott Professor of Surgery, the Johnson & Johnson Distinguished Professor of Surgery, and chair of the Department of Surgery at Columbia University College of Physicians and Surgeons. "Additional studies are needed to examine the increased incidence of stroke following TAVI."
According to the study authors, research is already under way on the next generation of TAVI devices that researchers hope will address the vascular complications encountered in the trial.
Treatment of Aortic Stenosis
Aortic valves, which regulate blood flow from the heart into the aorta, can fall victim, typically with age and the onset of cardiovascular disease, to stenosis (failure to open) and insufficiency (which leads blood to flow in the wrong direction back into the heart). Aortic stenosis results in a poor quality of life and a high rate of death, approximately 50 percent, in the first two to three years after diagnosis without surgical intervention. Approximately 300,000 Americans suffer from severe aortic stenosis.
In clinical practice, at least 30 percent of patients with severe symptomatic aortic stenosis do not undergo surgery for replacement of the aortic valve because of advanced age, left ventricular dysfunction, or the presence of multiple coexisting conditions.
The replacement valve used in the PARTNER trial is made of pericardial tissue leaflets hand-sewn onto a metal frame and implanted via a catheter into the left ventricle. It is then positioned inside the patient's existing valve using a balloon to deploy the frame, which holds the valve replacement in place. The procedure is performed on a beating heart, without the need for cardiopulmonary bypass and its associated risks.
The transcatheter valve procedure takes about 90 minutes, compared with four to six hours for open-heart surgery. In open-heart surgery, the surgeon cuts through the breastbone, stops the heart, removes the valve, and replaces it. Open-heart surgery can require a two- to three-month recovery period, compared with only a few days for the transcatheter approach.
The multicenter PARTNER trial, which has more than 1,000 patients, began in 2007 and will be completed in 2014. The results reported today reflect only the cohort of patients who are not considered candidates for surgery. The other arm of the trial, which compares transcatheter valves with surgically implanted valves, is ongoing. The executive committee of the trial includes two academic co-principal investigators, three interventional cardiologists, and three cardiac surgeons.
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About CRF and TCT
The Cardiovascular Research Foundation (CRF) is an independent, academically focused non-profit organization dedicated to improving the survival and quality of life for people with cardiovascular disease through research and education. Since its inception in 1991, CRF has played a major role in realizing dramatic improvements in the lives of countless numbers of patients by establishing the safe use of new technologies and therapies in interventional cardiovascular medicine.
Transcatheter Cardiovascular Therapeutics (TCT) is the annual scientific symposium of the Cardiovascular Research Foundation. TCT gathers leading medical researchers and clinicians from more than 90 countries around the world to present and discuss the latest developments in the field.
For more information, visit www.crf.org.
About NewYork-Presbyterian Hospital
NewYork-Presbyterian Hospital, based in New York City, is the nation's largest not-for-profit, non-sectarian hospital, with 2,353 beds. The Hospital has nearly 2 million inpatient and outpatient visits in a year, including more than 220,000 visits to its emergency departments -- more than any other area hospital. NewYork-Presbyterian provides state-of-the-art inpatient, ambulatory and preventive care in all areas of medicine at five major centers: NewYork-Presbyterian Hospital/Weill Cornell Medical Center, NewYork-Presbyterian Hospital/Columbia University Medical Center, NewYork-Presbyterian/Morgan Stanley Children's Hospital, NewYork-Presbyterian/The Allen Hospital and NewYork-Presbyterian Hospital/Westchester Division. One of the most comprehensive health care institutions in the world, the Hospital is committed to excellence in patient care, research, education and community service. NewYork-Presbyterian is the #1 hospital in the New York metropolitan area and is consistently ranked among the best academic medical institutions in the nation, according to U.S.News & World Report. The Hospital has academic affiliations with two of the nation's leading medical colleges: Weill Cornell Medical College and Columbia University College of Physicians and Surgeons. For more information, visit www.nyp.org.
About Columbia University Medical Center
Columbia University Medical Center provides international leadership in basic, pre-clinical and clinical research, in medical and health sciences education, and in patient care. The medical center trains future leaders and includes the dedicated work of many physicians, scientists, public health professionals, dentists, and nurses at the College of Physicians and Surgeons, the Mailman School of Public Health, the College of Dental Medicine, the School of Nursing, the biomedical departments of the Graduate School of Arts and Sciences, and allied research centers and institutions. Established in 1767, Columbia's College of Physicians and Surgeons was the first institution in the country to grant the M.D. degree and is now among the most selective medical schools in the country. Columbia University Medical Center is home to the most comprehensive medical research enterprise in New York City and State and one of the largest in the United States. Columbia University Medical Center is affiliated with NewYork-Presbyterian Hospital, the nation's largest not-for-profit, non-sectarian hospital provider. For more information, visit www.cumc.columbia.edu
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