New imaging technologies have led to less-invasive heart tests and treatments. That’s good news for patients and physicians.
Heart disease is the No. 1 killer of both men and women in the United States, accounting for nearly 25 percent of all deaths, according to the Centers for Disease Control and Prevention. Each year, more than 600,000 people die from largely preventable conditions related to heart disease.
Today, medical professionals are using technology that lets them look inside the body, assess potential problems and take steps to treat heart disease in the least invasive means possible. Doctors can use a variety of tests to observe the functions of the heart—how blood is flowing, how valves are operating and where blockages may be occurring—without ever picking up a scalpel.
“Imaging is an integral part of cardiac diagnosis and care,” says Dr. Kanny Grewal, medical director of the cardiac imaging laboratory at Riverside Methodist Hospital. From traditional X-rays to emerging technologies, radiology is helping doctors make new strides in detection and treatment.
Grewal says some patients arrive in his office after experiencing the classic symptoms of heart disease: chest pain, difficulty breathing, fatigue and lightheadedness. Others have no symptoms, but are concerned about a family history of heart disease. Screening is important, Grewal says.
“Up to 50 percent of patients who die suddenly of a heart attack have never had any symptoms before,” he says. “If we are really going to impact heart disease, we can’t wait for symptoms to develop.”
Doctors say there are numerous treatment options that address different conditions. Here’s a look at some of the most common diagnostic technologies.
One of the most frequently used procedures is angiography, which allows radiologists to visualize the vascular system and assess potential problems. Dr. Jeremy Buckley, an interventional cardiologist and chairman of the Snider Cardiovascular Institute at Fairfield Medical Center, says such procedures are useful for detecting impending blockages.
“We have a tendency to build up cholesterol in the walls of our heart arteries,” Buckley says. Suprisingly, it is not necessarily the severely narrowed passages that present the most danger, but those vessels that have only 20 percent or 30 percent blockages, he says. Such blockages are very unstable and may cause a major cardiac event with little or no warning. “Think of them as blisters,” he says. “They are fragile, and when they break open, the body will try to heal them.” The blood rushing to the area causes a clot, which blocks blood flow to the heart, resulting in a heart attack.
A computed tomography scan (better known as a CT or CAT scan) can diagnose other types of arterial blockage. “A cardiac CT looks at the heart structure and can detect calcium buildup in the coronary arteries,” says Dr. Martha Gulati, associate professor of medicine in the division of cardiology at Ohio State University. “This calcium score is predictive of the risk of future cardiovascular events.”
The CT is a form of coronary calcium scan, Grewal says. The equipment can capture an image in a split second and allow doctors to assess minute details and make predictions about a patient’s future health. “When you look at arteries where there is atherosclerosis, one of the common things you will find is calcium,” Grewal says.
Just as an X-ray machine can capture detailed images of bones, the CT scanner can detect calcium in much smaller amounts in the blood vessels. “We can screen for plaque years before it could cause symptoms,” Grewal says.
If calcium buildup is detected, doctors may advise a patient to take a much more aggressive approach to head off heart disease. That may include managing blood pressure and cholesterol and perhaps taking a statin medication, which can reduce heart attack risk by as much as 30 percent, Grewal says.
The transesophageal echocardiogram, or TEE, is a relatively new assessment tool that allows easy and effective examination of the heart. “The TEE is done with sedation, and is used when regular ultrasound just doesn’t answer all the questions,” Grewal says.
Using an endoscope fitted with an ultrasound unit, the TEE creates real-time, 3-D images. “The advantage is that the scope is just a few millimeters away from the heart,” Grewal says. “It allows you to get very high-quality images of the heart as it is moving.” The test can detect structural defects such as leaky or narrow heart valves and allows doctors to plan a surgical procedure in great detail.
Brian Bottomley, 74, underwent a TEE in December. He’d been getting treatment for arrhythmia for about two years when, last summer, he began experiencing shortness of breath that got gradually worse. Grewal diagnosed him with a valve problem in addition to the arrhythmia.
The imaging technology also allowed Grewal to plan a course of treatment, which included repairing Bottomley’s mitral valve and a catheterization to fix two small blockages. “I’m so glad they were able to diagnose it without any invasive procedure,” Bottomley says. The retired machinist is preparing to undergo rehabilitation and a strengthening program at the McConnell Heart Health Center. His short-term goal is to return to his cycling hobby.
Even the old-fashioned methods still play a useful part in assessment and treatment of a wide variety of heart ailments. “This is a radiology study, not as sexy as the others,” Gulati says. “But we can detect heart enlargement, fluid in the lungs, potential prior heart surgery, dilated aorta, etc.”
It is still a faithful standby, and is one of the first tests ordered when someone comes to the emergency room complaining of chest pain or shortness of breath, she says.
When patients present mild cardiac symptoms or have a family history of coronary disease, doctors may order a stress test. All stress tests begin with baseline readings of the heart at rest. Readings are then repeated after vigorous exercise, typically done on a treadmill.
Several types of imaging may be used in conjunction with stress tests. In the most basic, ultrasound equipment is used to capture images of the heart while it is still racing, within 60 to 90 seconds of completing exercise, Grewal says. Comparing the before and after images is a way to detect problems. The equipment utilizes essentially the same technology as in prenatal ultrasounds. A wand delivers sound waves that bounce off internal structures, allowing the machine to map out an image of what is going on inside the body.
In a nuclear stress test, a mildly radioactive isotope is injected into the patient’s bloodstream. A special camera tracks the progress of the isotope through the body. “Nuclear stress testing is used to assess blockages in the coronary arteries,” Gulati says. “It can also tell us how well the heart is squeezing.” The radiation dissipates within a few hours, Grewal says.
A CAT scan can also be used in conjunction with a stress test. After exercising, the patient lies on a table while the scanner maps out internal structures and creates a picture of the pathways through which blood is flowing.
An MRI stress test uses the same basic procedure, but magnetic resonance imaging captures pictures of the heart as it pumps. “This looks at many things in the heart: its structure, its function, the coronary arteries, the blood flow to the heart muscle,” Gulati says. “It can detect small vessel disease using a very unique stress testing.”
Kim Skipper, 41, underwent an MRI stress test when nuclear stress tests failed to detect severe coronary artery disease. Before her diagnosis at age 33, she experienced chest pain, arm pain, blurred vision and heartburn. But a nuclear stress test showed nothing. Given her family history of coronary artery disease, Skipper and her sister pushed the doctor to investigate further. A catheterization procedure revealed a 99 percent blockage in her main right artery.
Several more bouts of symptoms led to numerous nuclear stress tests, all of which came back negative. Yet each time, the catheter procedure found blockages: a 100 percent blockage in her main left artery, then three more blockages, including the complete closure of a previously placed stent. After getting seven stents over the course of several years, doctors decided to try an MRI stress test.
“The MRI showed several new blockages, plus scarring on my heart, which showed I had probably suffered several minor heart attacks, although I never knew it,” Skipper says.
Now, Skipper foregoes three or four nuclear stress tests a year in favor of the MRI test. With 10 stents now in place, she is beginning OSU’s cardiac rehabilitation program. “Just having that one test showed so much and made such a difference,” she says.
Cardiac imaging has proven useful not just in treating the very prevalent coronary artery disease, but also in cases of heart defects that are detected in childhood or even before birth.
“This is extremely important, because about one of every 100 children is born with some sort of congenital heart defect,” says Dr. John Kovalchin, director of echocardiography at Nationwide Children’s Hospital. For most, such defects are mild and do not require treatment, he says. Others require intervention.
Many patients are referred by their primary care physicians, who may notice a heart murmur or make a referral when a patient complains of chest pain. Other defects are detected right after birth or in utero, thanks to routine ultrasound tests often combined with a complete inventory of family history.
A fetal echocardiogram can detect a variety of potential hurdles. When the mother has a heart problem, is taking certain medications or a fetal chromosomal abnormality has been detected, doctors sometimes expect a heart defect in the unborn child. Also, when a malformation is detected in one body system, doctors check all the other systems; babies with one defect have defects in multiple systems about 30 percent of the time. Surgery performed prior to birth is rare, but early detection is still important.
“It lets us know what to expect and where to deliver,” Kovalchin says. In many cases, an infant born near the parents’ home will be transferred to a facility where very specialized care is available. Other times, circumstances won’t allow for that.
“One of our patients was diagnosed with a very significant heart problem before birth,” Kovalchin said. “We knew there would be problems immediately, and that transferring the child might lead to a higher risk. In that case, the mother delivered at Children’s, and the child was taken directly to the cath lab.”
When other imaging tests show a patient is at risk for an impending cardiac event, a catheterization may be in order. This procedure can remove blockages and widen narrowed arteries using radiological imaging to detect problems and minimally invasive procedures to fix them.
“If there is a suggestion of a buildup of cholesterol, or coronary stenosis, we may proceed to the heart cath lab,” Buckley says. “We numb an area in the groin or the wrist and insert a tube, which acts as sort of a one-way valve.” The tube is about the size of a coffee stirrer, and is used as a port through which longer tubes are threaded, all the way up to the heart. The tubes are designed to travel through the circulatory system without nicking the delicate vessels. With a practiced hand and imaging technology, a doctor can guide the tubes right through the aorta and into the coronary arteries, where heart attacks begin.
Technology has taken medical science to places doctors only dreamed of a generation ago. Physicians are assessing, repairing and rebuilding hearts through the tiniest of incisions. “Even 20 or 30 years ago, you sawed through the breastbone, stopped the heart and sewed a patch on,” Kovalchin says. “Things are so different now.”
Kristin Campbell is a freelance writer.
Reprinted from the April 2012 issue of Columbus C.E.O. Copyright © Columbus C.E.O.