New 3-D Imaging at PHD to Resolve Questions about Heart Before Surgery|
DALLAS – Cardiovascular surgeons and anesthesiologists at Presbyterian Hospital of Dallas are the first in North Texas – and among the first in the state – to begin using a new type of echocardiogram that provides the first-ever live, three-dimensional images of the beating heart moments before surgery. The technology is expected to help surgeons better determine the course of open-heart surgeries and better treat people with heart failure, one of the leading causes of death in the United States.
"Ultrasound imaging is beneficial because it is a relatively non-invasive way to look inside the body," said Dr. Melvin Platt, medical director of cardiovascular surgery at Presbyterian Hospital of Dallas. "But until now those images left many unanswered questions. There's no question this technology adds a whole new dimension to what we're able to see."
The 3-D images are generated through a probe inserted into the patient's throat before surgery. The device uses ultrasound, or high-frequency sound waves, to produce moving images of the body's internal soft tissues. The common cardiac ultrasound used up to now provided only flat, two-dimensional images in black and white.
"This is an important technology because it will allow us to better determine the health of different parts of the heart," Platt said. "In some cases, it may eliminate the need to replace heart valves that we otherwise would not have known were healthy. But its primary value is in giving us better definition of valve abnormalities that do require treatment so the most effective therapy can be carried out."
Until now, doctors only could see 3-D images of heart valves by actually looking directly at the valves during surgery - after the surgical site was opened and the patient had been put on the bypass machine. "At that point, the heart isn't moving, so you're not able to determine the functional integrity of the valve as it pumps blood," Platt said. "With these live 3-D pictures, we can now see those valves at work."
The 3-D images also can be taken before surgeons close the surgical site, telling them whether any leaks exist or additional procedures are needed.
"Without this, you're not able to get some important feedback until the procedure is over and the surgeon has closed the patient up," said Dr. Thomas Russell, a cardiac anesthesiologist on the medical staff at Presbyterian Hospital of Dallas. "Now, we can generate live 3-D images in the operating room during surgery, which tells us if there are any complications that need to be addressed."
Because the images provide more information about the heart, surgeons will better know which parts need to be examined - and whether they can be repaired rather than replaced. Valve replacement surgery, while an effective treatment in most cases, often requires that patients take blood thinners for the rest of their lives, which can increase the risk of stroke. Repaired valves also tend to last longer than replacement valves, which come from animal or cadaver tissue.
Heart failure, which includes faulty mitral and aortic heart valves that can now be seen more clearly with the new 3-D TEE technology, is the leading cause of hospital admissions in the United States and one of deadliest diseases in the world, according to the American Heart Association.
The mitral and aortic valves ensure that blood flows through the heart the right way at the right volumes. The mitral valve is located between the heart's left atrium (upper, holding chamber) and left ventricle (lower, pumping chamber). The mitral valve has two flaps. Mitral valve problems can include one or both valve flaps becoming enlarged, and some of their supporting tissue may be too long. When the heart pumps, the mitral valve flaps don't close smoothly or evenly. Instead, part of one or both flaps collapses backward into the left atrium. This sometimes lets a small amount of blood leak backward through the valve. This may cause a heart murmur.
The aortic valve is located between the left ventricle, or lower chamber of the heart, and the largest artery (aorta). The left ventricle pumps oxygen-rich blood into the aorta, which carries blood to the brain and the rest of the body. Problems with the aortic valve can include aortic valve stenosis, a condition in which the aortic valve has become narrowed or constricted and does not open normally. When the aortic valve becomes stenotic, the ability of the left ventricle to pump blood out of the heart to the aorta and other arteries is impaired. The organs receive an insufficient supply of oxygen-rich blood, and blood may "back up" into the lungs, causing shortness of breath and other serious complications.
According to the American Heart Association, there are about 5 million heart failure patients in the United States, and 550,000 new cases of heart failure diagnosed across the nation every year. This includes 10 out of every 1,000 people over the age of 65. Of newly diagnosed patients under the age of 65, about 80 percent of the men and 70 percent of the women will die within eight years. In people diagnosed with heart failure, sudden cardiac death occurs at six to nine times the rate of the general population.
The new 3-D TEE system at Presbyterian Hospital of Dallas is being used to better treat people with mitral and aortic valve problems and other forms of heart failure.
"This is wonderful technology that will allow us to better determine the proper course of treatment, ultimately improving outcomes and lessening the impact on the surgical patients," Russell added. "With enough computer power you can generate astronomical imaging power and, in turn, see parts of the body as they function that were previously visible only by opening the patient up with surgery."
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