New Option for Aortic Valves
Replacement Without Surgery
Patients with narrowed heart valves who are too sick to undergo traditional open heart surgery to replace those valves now have a nonsurgical option that can relieve their symptoms and possibly prolong their lives.
The procedure, known as transcatheter aortic valve replacement (TAVR), is currently being used to replace narrowed aortic valves. Similar transcatheter approaches may one day be used to fix mitral and pulmonary valve problems as well.
"Patients who have trouble simply walking can experience dramatic increases in their activity levels," says
Jeffrey Popma, MD, Director of
Interventional Cardiology Clinical Services at the
CardioVascular Institute (CVI) at
Beth Israel Deaconess Medical Center. "Substantial symptom improvements occur in the majority of patients treated with transcatheter replacement."
"Open, surgical replacement remains the standard treatment for diseased aortic valves," says
Kamal Khabbaz, MD, Chief of
Cardiac Surgery at the CVI. "But for patients who are not candidates for the traditional operation because of advanced age, frailty or multiple conditions, it is now possible for patients to receive a surgical valve without surgery. Placement through a catheter can make a huge difference in these patients' lives."
Valve Choices for Open-Heart Replacements »
Aortic Stenosis Common in Elderly
People with aortic valve stenosis (a narrowing of the aortic valve) typically suffer trouble breathing, chest pains, dizziness, and fatigue. Many cannot even walk enough to perform their daily activities. Left untreated, severe aortic stenosis can lead to heart failure or death.
The aortic valve is located between the left ventricle of the heart and the aorta, the largest conduit in the body and the one which carries the entire output of blood from the heart. When the valve is narrowed, blood flow is impaired and the heart must pump harder than normal to get blood to the rest of the body.
About 5 percent of people over age 80 suffer from aortic stenosis, and 70,000 patients undergo surgical aortic valve replacement each year in the United States. However, approximately 7,000 are felt to be "high risk" for surgical aortic valve replacement, and another 35,000 Americans are too sick to even undergo the open heart operation. Options for these patients have been limited.
But in the last few years, interventional cardiologists and heart surgeons have developed nonsurgical methods of replacing these diseased valves. The procedure involves inserting an artificial valve by snaking a catheter through an artery. The artery may be accessed through small incision in either the patient's groin or chest.
Dr. Popma is one of two principal investigators heading up a national clinical trial evaluating the safety and effectiveness of the procedure using an experimental artificial valve, the Medtronic CoreValve. This is a self-expanding, spring-like bioprosthesis made from pig tissue fixed to a Nitinol frame.
BIDMC is CoreValve Clinical Trial Site
The CoreValve has been approved in Europe since 2007. Results of the current study will be reviewed by the
U.S. Food & Drug Administration when it decides whether to allow the CoreValve to become commercially available in the United States.
In addition, there is currently one other type of transcatheter valve approved for use in the U.S. A study of patients with severe stenosis who received that valve showed one-year death rates to be about half that of those who had standard surgery.
Describing the CoreValve procedure, Dr. Popma says, "In collaboration with our heart surgeons, we use tubes and wires to deliver an artificial valve that is sewn on to a stent. With release of the stent frame, the old valve is pushed out of the way and the new valve is implanted."
The CoreValve study - which is taking place at 44 institutions (including BIDMC) and enrolling 1,500 subjects - includes patients deemed "high risk" as well as those considered "extreme risk" or inoperable patients. Those at high risk are randomized into two groups - one undergoing the traditional open-heart surgery and the other undergoing the nonsurgical procedure. Patients deemed "extreme risk" all receive the nonsurgical procedure.
Multidisciplinary Team Works Side By Side
At the CVI, cardiac surgeons screen potential valve replacement patients to determine the most appropriate therapy.
When the transcatheter approach is chosen, Dr. Popma and
Dr. Roger Laham, both interventional cardiologists, work side-by-side with Dr. Khabbaz or
Dr. David Liu, another CVI heart surgeon. The team performs the procedure in a special, high-tech hybrid operating room specially equipped to allow interventional cardiologists and heart surgeons to work together.
"We are very excited to be able to offer patients with life-threatening aortic valve disease the potential opportunity to participate in this research study," said Dr. Popma.
Above content provided by the CardioVascular Institute at Beth Israel Deaconess Medical Center. For advice about your medical care, consult your doctor.
Posted August 2012