CCTA: The Road to Acceptance

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The advancement of imaging technology is invariably followed by a host of related challenges. Many of these challenges are questions raised by payors and answered by various medical associations in an effort to ensure a seamless transition from research and development to practical use. Coronary CT angiography (CCTA) has followed this well-worn path. As one may expect, physicians were pleased with CCTA as another arrow in their treatment quivers, while payors were concerned about overutilization, specifically the use of CCTA as a screening tool for patients without symptoms or risk, or at low risk, for coronary-artery disease (CAD). Appropriately, some medical organizations, including the American College of Cardiology, the ACR, and the Society of Cardiovascular Computed Tomography, have developed appropriateness criteria for CCTA that establish guidelines for proper use of this technology. Selecting the Ideal Candidates William Shea, MD, is the vice president and director of the 3D imaging lab and cardiac imaging for NightHawk Radiology, Couer d’Alene, Idaho. Shea has been involved in furthering the use of CCTA within appropriate guidelines. Shea recognizes that one of the important points in a higher-profile CCTA program is clearly identifying those patients who are candidates for the study. “At this point in time, everyone in the medical community agrees that CCTA should be performed on patients who are either symptomatic with angina or chest pain that is unclear in its origin or are at high risk for CAD who will be undergoing surgical procedures,” Shea says. “For instance, a candidate for aortic-valve surgery or abdominal aortic aneurysm surgery who fits the profile of high risk of possible periarterial disease is a candidate for cardiac CT preoperatively.” He continues, “Another large group includes those who have chest pain and an equivocal ECG or an equivocal stress test, or patients who have had atypical chest pain—in other words, symptomatic individuals or patients who have a high indication that they will be undergoing surgical procedures.” CCTA, however, is not just for the more familiar cases. According to Shea, there are smaller niche groups that must be considered. “Other candidates are patients who have congenital heart disease, especially those who have undergone surgical procedures as children and are now approaching adulthood. Another niche group is those patients who have had coronary bypass surgery who are going to undergo reoperation. The last niche group would be those with suspected coronary anomalies,” he says. CCTA as a Tool in the ED Shea’s criteria clearly indicate that a large group of patients can benefit from this test, but is there a place for CCTA in the emergency department (ED) for patients who present with chest pain? Despite the cost-containment concerns of payors, will it ever be appropriate to screen a population for CAD using CCTA? “Each year, there are 4 to 6 million ED visits for chest pain in the United States,” Shea says. “Somewhere between 5% and 10% of these patients don’t need a scan; those patients can go right to the cath lab or right into therapy, whatever that therapy is. They don’t need anything extra. We’re still left, though, with 80% to 90% of the patients presenting with chest pain. CT fits because what we do today is observe those patients, get serial ECGs and serial biomarkers, and wait at least 12 hours to see if there’s any significant change in the ECG or biomarkers. If they’re still within the normal range, the patient has a stress test; if that’s OK, then they discharge the patient.” Shea continues, “We’re talking 18 to 24 hours for a great majority of these patients. This incurs a large expense for the hospital. In that patient population, if you could do a CT scan and the results were normal, then all these people could be discharged, and there could be a great savings to the system and a great benefit to the ED.” In real time, Shea reports a remarkable difference in care. “A CT scan could be ordered by the ED physician, and even if the nurses and technologists have to be called in, we’re still talking only a couple of hours—and you gain so much information with a CT scan. When it is normal, the patient can be discharged with confidence,” he says. Studying the Potential Benefits As is often the case, costs and benefits enter the picture. For Shea, there is a clear difference not only in the quality of patient care, but in the quantity. Here, less may be more. “What we need to do in the medical community is demonstrate that this is not just another layer of cost and another layer of examination,” Shea says. He adds, “We at NightHawk are involved in a study called the High Risk Plaque Initiative. In this study, we are evaluating asymptomatic patients for CAD and stroke in an attempt to update the Framingham risk factors that we now have. The study involves 8,000 patients from around the country, and these patients are having a series of screening studies that include cardiac CT. Down the road, this study will try to identify trends and risks associated with the presence of disease in asymptomatic individuals at the time of their involvement in the study.” CAD is a health issue to which too much attention cannot be paid. “Nearly half the people who present with CAD present with either sudden death or a heart attack,” Shea says. “They have a large particle of vulnerable plaque sitting in their coronary artery, not causing any blockage at all; it’s just sitting on the wall of the artery. That form of plaque ruptures and there is an immediate change—downstream, there is no oxygen feeding the heart, and that results in the heart attack or sudden death. We believe that cardiac CT may be the best mechanism for identifying those patients who have vulnerable plaque.” Identifying Referrers As acceptance rises for cardiac CT, there will undoubtedly be groups of physicians who are in better positions to identify likely candidates for the study. Shea notes that these physician groups remain about the same as those who have traditionally identified at-risk patients over the years. “The great majority of patients will be referred by their family practitioner, internist, or cardiologist for cardiac CT,” Shea says. “Family practice physicians and internists are going to have this study available, so that when their patients come in with CAD and either an equivocal ECG or equivocal laboratory results, they are going to have the opportunity of ordering it in lieu of any other cardiac imaging study, such as a nuclear cardiac study.” He adds, “In the cardiologist community, there are going to be cardiologists who feel strongly in favor of cardiac CT, and they will order cardiac CT rather than nuclear cardiology or catheterization for this group of patients.” Still, even with physician acceptance, there is a large segment of the health care system that has its own criteria for determining overall value. “If we can demonstrate the cost-effectiveness of cardiac CT in the ED setting, then ED physicians are going to be ordering an awful lot of these,” Shea says. Managing the Educated Patient Shea says that the first move by a referring physician toward cardiac CT is patient selection, but notes that physicians should expect to encounter a new generation of patients who feel empowered to direct their care. “Physicians clearly want to evaluate those patients who are at risk of CAD and who have symptoms that are not clear-cut—who clearly have no contrast reaction and no allergies to the contrast, and who would prefer to have a cardiac CT rather than catheterization,” Shea says. “The family practitioner or internist is going to have a large group of patients who have become aware of this technology and who are going to push to have this done, rather than undergoing catheterization. Some of this is going to be patient driven,” he predicts. Developing a Successful Protocol Developing a cardiac CT program has several important steps that eventually involve multiple departments in any radiology practice. “One of the things that makes cardiac CT and cardiac MRI different is the level of expertise required of the technologist and of the physician,” Shea says. “The requirements and the certification to get the expertise and education are greater, so that’s one of the processes that any radiology group is going to have to undergo to get their technologists and their physicians appropriately certified to do this.” He adds, “Unless you have the correct equipment, you cannot do this, so you need to have the appropriate CT and the appropriate processing, and you need to have the protocols in place to make this work. There is special certification, both by the ACR and by the American College of Cardiology, so that the physician who interprets the study is certified by one board or the other. There are things that some radiologists have not typically become familiar with that there is a requirement to learn, such as the appropriate guidelines for the administration of beta blockers. It’s not a big issue for interventional radiologists; however, diagnostic radiologists may find that to be a challenge.” Aside from the medical education required, there are technical aspects to grasp as well. “All of data from these cardiac CT tests need to be processed, and it may be a challenge for physicians to learn the software that provides us with the images that we clearly need,” Shea says. Overcoming the cardiac CT challenges, whether it is proving cost effectiveness or upgrading physician skills, is designed to improve patient care. For Shea and other physicians, this has always been the goal.