Cardiac CT represents vast clinical and business potential for radiologists. And unlike other forms of cardiac imaging, new applications such as coronary CT angiography offer an opportunity for radiologists to go it alone.
"Prior to coronary CTA, any cardiac imaging that we did required cardiologists," said Dr. David Dowe, COO of Atlantic Imaging in Galloway, NJ. "We couldn't do a stress thallium test without cardiologists doing the ECG portion. But coronary CTA is something that cardiologists can't do alone."
Coronary CT angiography (CCTA) includes a complete evaluation of the lungs and chest. Interpreting physicians need to know about CT artifacts to ensure that findings are accurately identified.
"This is the first cardiac study that a radiologist is ideally suited to do alone," Dowe said. "It's just a question of getting the message out there."
Dowe, who has performed about 1000 CCTA studies to date, is one of many enterprising radiologists capitalizing on the opportunities CCTA offers. Launching and maintaining a successful cardiac CT imaging program requires a concerted educational effort among referring physicians, with an emphasis on primary-care colleagues as well as cardiologists.
For the past five months, Dr. Brent Greenberg, who runs the one-man shop of Greenberg Radiology in the Chicago suburb of Highland Park, has offered "virtual cardiac angiography." He uses that term in marketing CCTA to differentiate it from standard coronary calcium scoring tests.
"CT angiography is revolutionary, particularly of the coronary arteries," Greenberg said. "There are no false positives, and a normal result means no significant disease is present."
Awareness of the exam is percolating among patients, referring physicians, and insurers across the country. Part of that buzz was sparked by former President Bill Clinton's emergency quadruple bypass in September, which sent worried well patients to the phone to schedule a checkup. A Chicago Sun-Times article in the fall profiling Greenberg and his use of CCTA prompted a surge in calls to his imaging center.
Moreover, in the past year, two key research teams have documented utilization trends that favor noninvasive cardiac imaging over traditional cardiac catheterization and angiography.
ECRI, a nonprofit health services research agency in Plymouth Meeting, PA, predicts a rapid rise in the use of noninvasive CT angiography. CTA will be performed more frequently as a complement to or replacement for other cardiac exams such as diagnostic cardiac catheterization, MRI, and nuclear imaging. ECRI also predicts that the number of diagnostic cardiac cath procedures will decrease substantially over the next few years, particularly for assessing plaque, stenoses, and myocardial viability and for ruling out atherosclerosis.
Given the aging population and an ongoing emphasis on early diagnosis and treatment, ECRI predicts that noninvasive high-end multislice CT will diffuse rapidly over the next several years for cardiovascular and angiographic applications.
IMV Medical Information Division, a research firm in Des Plaines, IL, notes a similar trend. The number of cath lab cases performed in 2002 remained level in the U.S., after increasing 17% between 1998 and 2002, according to a company survey released in September. Of cardiac cases performed in 2002, nearly three million were coronary, including diagnostic-only, therapeutic-only, and combined diagnostic and therapeutic.
The seemingly ripe market doesn't necessarily mean that CCTA referrals are easy pickings, said Dr. Stephen Koch, medical director of Imaging Heart, which runs three imaging centers in New York City that specialize in CCTA.
"Radiologists who think that just because they offer a cardiac CTA program, the referrals will come flowing in are kidding themselves," he said. "They need to be out there pounding the pavement, sitting down with referring physicians, and explaining how these studies are done."
Why the need for a big sell? Few published studies based on current 16-slice technology have documented cardiac CT's clinical acumen, and most referring physicians are skeptics, Koch said. As with any new technique, the desire for data comparing CCTA with cardiac catheterization is high among referrers, particularly cardiologists.
"Most of cardiology practice is data-based," he said. "They don't like to accept any new technology without literature ad nauseum on that particular topic. But this technology is only two and a half years old, and the literature is based on four-slice technology."
When Greenberg is queried by would-be referrers about the viability of CCTA versus a conventional angiogram, he has answers at the ready.
"We can determine whether it is a soft plaque or a hard plaque that is causing a narrowing of the lumen of the artery," he said. "We can see anomalous coronary arteries and determine where their origins are. And we can see patency of a bypass graft or stents. It's a relatively noninvasive test, requiring only an IV injection of contrast."
Persuasive data may come in the form of a 10-year multisite study launched by the National Institutes of Health in 2000. The $68 million Multi-Ethnic Study of Atherosclerosis (MESA) is studying new ways to detect heart disease early, before symptoms result. MESA focuses on 6500 participants, half male and half female, aged 45 to 84, of diverse ethnicities. None had known heart disease at the time of enrollment. In addition to standard risk factors, socioeconomic data will also be collected.
MESA is using CT to assess coronary arteries. MRI and ultrasound will also be employed to evaluate various aspects of cardiovascular disease.
"When MESA is completed, and if CT performs as I think it will, then I expect a big surge in terms of interest in screening asymptomatic individuals for the possibility of coronary artery disease," said Dr. William Stanford, a professor of radiology at the University of Iowa and a board member of the North American Society for Cardiac Imaging. "It will be the definitive study that sorts out all the parameters."
Greenberg has already identified patients best suited for cardiac CT:
-patients at high risk for heart disease due to standard risk factors such as smoking, obesity, diabetes, high cholesterol, or strong family history;
-patients post-coronary bypass surgery, angioplasty, or stents for follow-up;
-patients who have had chest pains or other symptoms but normal cardiac tests; and
-patients with no symptoms who have had abnormal cardiac testing, including stress electrocardiogram, stress echocardiogram, and stress thallium imaging.
"The last category is the one into which President Clinton fell," Greenberg said. "And a good 25% of these stress echoes, stress thalliums, and stress ECGs are false negative and false positive. They could be normal, and yet you still have significant disease."
Dowe contends that coronary CTA is the only test that can look at the wall of the coronary artery noninvasively.
"What causes coronary artery disease is in the wall of the coronary artery," he said. "A cath exam looks at the hole, it doesn't look at the donut. The disease is in the donut."
At Atlantic Imaging, patients, referring physicians, and insurers are enamored with cardiac CT, according to Dowe.
"The number one indicator for a patient coming here is chest pain or chest pain with positive stress test," he said. "Patients receive a CCTA before the cath procedure, and 84% of the time, it's either normal or only mild plaquing, and we've saved them the cath experience."
In about 13% of cases, Dowe recommends a follow-up stress test, and in 3%, a cardiac cath procedure. Primary-care physicians who refer their patients to Dowe for CCTA appreciate the fact that those patients will return.
"Whether primary-care doctors admit it or not, they do not like sending patients to cardiology because they lose them," he said.
Yet the biggest referrer for CCTA at Atlantic Imaging is a cardiologist who sends patients after performing a stress test but prior to scheduling a catheterization, Dowe said.
Radiologists would be wise to educate both primary-care referrers and cardiologists about the benefits of cardiac CT. Because patients with normal results or only mild plaquing can be managed without cardiology intervention, Koch predicts that cardiac CT will spur a change in traditional referral patterns for cardiovascular imaging.
"Because CTA can determine whether this is cardiac disease or some other etiology, the patient can be triaged at the primary medicine level," Koch said. "When they do visit a cardiologist's office, they will have the answer to why they are having chest pain."
WAYS AND MEANS
Despite an uptick in interest in some areas of the country, many referring physicians have adopted a wait-and-see approach to cardiac CT. Education is key to launching the service. In Chicago, Greenberg has extended invitations to referring physicians to undergo the $1500 test free. The exam includes a personal review of the results, and many have taken him up on the offer.
In New York City, Koch spent nearly two years presenting roundtables, grand rounds, and presentations to multispecialty groups about cardiac CT. The practice now claims more than 200 cardiologists among its referral base.
"There is such competition for patients today," he said. "Referrers need all the bells and whistles they can get. And if they can say, 'We work with Imaging Heart, and we believe in CT angiography,' it may attract patients."
When it comes to cardiac CT's diffusion, much will depend on the philosophy of the local cardiologists. At the University of Iowa Medical Center, the loss of a cardiology team that was actively interested in noninvasive cardiac imaging has affected CT procedure volume and case mix, Stanford said.
Radiologists still evaluate nearly all aortas and perform pulmonary artery embolism imaging, as well as provide mapping of pulmonary venous connections and others such as coronary sinus. But volume is down, he said.
"We are not doing the kinds of cases nor the numbers of cases we were doing in the past," he said. "The current cardiology team isn't sending us patients for imaging; they are doing more echoes and caths on their own instead."
It's that kind of standoff that administrators at Cabrini Medical Center in New York City hope to avoid. Earlier this year, the 474-bed community hospital merged its radiology and cardiology departments to create a new cardiovascular medicine and integrated imaging department, headed by a cardiologist recruited from Mount Sinai School of Medicine.
"We've traditionally had a small cardiology program and a small radiology program," said Sean Healy, vice president of ancillary services at Cabrini. "We merged them to take better advantage of the potential offered by advanced cardiac imaging technology like CT and MR."
Cabrini partnered with Global Healthcare Systems, a financing company in Barrington, IL, for help in purchasing its new 16-slice CT scanner and an MR device. The hospital also plans to expand into outpatient imaging in 2005.
Getting the equipment and patients in the door is only part of the equation. The tricky next step is payment. No CPT code exists for coronary CTA, although the Centers for Medicare and Medicaid Services is at work to develop one, Dowe said.
Mastering the maze of details involved in launching a cardiac imaging program is a major part of Healy's job, and payment issues loom large.
"There are a million little things to get right in order to be successful financially, from charge capture issues to CPT codes, equipment, staffing, and training," he said.
In Chicago, insurers are beginning to be aware of the study, but, currently, Greenberg is offering the exam on a self-pay basis for screening. He expects that insurers will ultimately cover CCTA for symptomatic patients, however.
In New Jersey, Medicaid pays for CCTA at the level of a chest CTA or pulmonary embolism study, as does the second-largest private insurer serving the state.
Dowe expects insurers to come onboard with payment once they see the wisdom of replacing a $6000 exam with a $1500 one.
"The insurance companies are excited to have an alternative to the self-referred cardiology market," he said.
Insurers also appreciate Dowe's personal touch. Within 15 minutes of CCTA completion, he is sitting with patients explaining the study findings. It's pro bono time that is part of the center's marketing effort.
Research agency ECRI predicts that advanced technology such as new 32-, 40-, and 64-slice scanners will increase the range of cardiac CT applications. Early users at luminary sites expect the new scanners to have a dramatic impact on CT's ability to detect relevant obstructions in the coronary arteries and bypass grafts. It may also provide quantitative measures of flow in the arteries and heart muscle.
Some radiologists performing CCTA are already anticipating the impact that the new scanners will have on their practices. Koch, for example, predicts that a 64-slice scanner will allow him to double Imaging Heart's average volume of 15 cases per day.
But Greenberg believes 16-slice CT will work fine for coronary CTA in outpatient settings.
"The 64-slice scanner doesn't change the thickness of the slices or the speed of the rotation in the tube," he said. "All it allows you to do is cover more anatomy in the same amount of time. In terms of clinical capability, the 16-slice is perfectly adequate."
The faster scanner may be warranted in the hospital, where sicker patients may have a tough time holding their breath for 20 seconds. In addition to breath-holding, a successful exam requires that patient heart rates measure below 70 beats per minute. Typically, patients scheduled for outpatient CCTA take an oral beta blocker the night before the exam, he said.
While 32- and 64-slice scanners may not be a clinical necessity, Dowe points out practical and marketing advantages. Faster scanning speeds avert the possibility of variable heart rates.
"It currently takes us from 15 to 20 seconds to scan the heart, which means someone's heart rate can go up slightly, go back down, and then go up again during that time frame," he said. "If you are only scanning during a four-second interval, nobody's heart rate varies over four seconds."
That makes coronary CTA possible in even the sickest patients, he said.
"And it allows me to advertise, 'Give us four seconds, and we'll give you a lifetime,'" he said.