Nonsurgical Option Now Available for Aortic Valve Replacement
By Michael Lasalandra
Beth Israel Deaconess Medical Center correspondent
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.
"In patients who are not suitable candidates for the traditional operation, this innovative procedure can make a huge difference," says Dr. Jeffrey Popma (pictured at right), Director of Interventional Cardiology Clinical Services at the CardioVascular Institute at Beth Israel Deaconess Medical Center. "Patients who have trouble simply walking can experience dramatic increases in their activity levels. Substantial symptom improvements occur in the majority of patients treated with TAVR."
Those 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.
The usual fix for the problem in elderly patients generally requires open-heart surgery.
"It is a substantial operation, but patients who can undergo this procedure feel much better after the valve replacement," says Dr. Popma.
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 undergo the open heart operation at all. Options for these patients have been limited.
But in the last few years, interventional cardiologists and heart surgeons have developed a nonsurgical method of replacing these diseased valves. The procedure involves inserting an artificial valve by snaking a catheter through a small opening in the patient's femoral artery or other access point to get it to the heart.
Dr. Popma is one of two principal investigators heading up a national clinical trial evaluating the safety and effectiveness of the procedure using a new artificial valve, the Medtronic CoreValve. This is an experimental self-expanding, spring-like bioprosthesis made from pig tissue fixed to a Nitinol frame.
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 collaborations 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 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 getting the traditional open-heart surgery and the other getting the nonsurgical procedure. Patients deemed "extreme risk" all receive the nonsurgical procedure.
At the CardioVascular Institute, Dr. Popma and Dr. Roger Laham, both interventional cardiologists, work side-by-side with heart surgeons. The procedure takes place 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 January 2013