CTA: collaboration and turf issues in noninvasive imaging

It seems unlikely that CTA use will be restricted to the hospital radiology department or its interpretation limited to radiologists.

Rapid developments in the technology of multislice computed tomography angiography and the results of early clinical research have spurred the excitement and imagination of multiple physician specialty groups interested in cardiovascular imaging, not only cardiologists and radiologists but also nuclear medicine physicians, vascular medicine specialists, surgeons, emergency room physicians and primary care physicians.

As evidence is gathered to more precisely define the role of multislice CTA in clinical practice, it is becoming clear that widespread application of this technology will require cooperation of multiple individual physicians and physician specialty groups.

Cardiologists and radiologists both lay claim to a role in supervising and interpreting CT coronary angiograms. Cardiologists bring their training and experience in cardiac catheterization, coronary angiography and coronary intervention to CTA, as well as additional imaging skills in nuclear cardiology, echocardiography and MRI. Cardiologists also have extensive knowledge of cardiovascular pathophysiology and treatment options, and powerful direct, personal contact with patients.

Radiologists are specifically trained in the use of CT and are familiar with CT imaging protocols and the use of workstations. While recently trained radiologists often have little training or experience in coronary angiography, they are generally well trained in peripheral angiography, including CTA.

Samuel Wann

Radiologists have traditionally controlled the use of CT machines in hospitals through exclusive contracts but have little if any direct contact with patients and little control over ordering of CTA or integration of the results of CTA into the clinical care of the patient.

Economic interest

The issue of which specialist provides CTA services is especially timely because cardiac imaging is one of the biggest and fastest growing costs of health care. Much of this growth in imaging has occurred outside hospitals, in specialists’ offices, and is not concentrated in large general radiology departments.

The American College of Radiology has mounted a public relations campaign blaming cardiologists and other specialists who are engaged in providing imaging services in their offices for these rising costs, charging that economic self-interest has resulted in inappropriate use of imaging by nonradiologists.

Normal left anterior descending coronary artery (LAD) in patient presenting to the emergency room with chest pain. The right and circumflex coronary arteries were also normal. The entire coronary tree was imaged during a single breath hold using 100 cc of non-ionic IV contrast.

Radiology’s own economic self-interest is clearly evident. Radiology wants to avoid “losing” CTA to cardiology, as it perceives it “lost” coronary angiography, echocardiography and nuclear cardiology. The desire to exclude nonradiologists from imaging extends well beyond cardiology to include OB/GYN, ophthalmology, vascular surgery, orthopedics and others.

The ACR promises to reduce expenditures for imaging services by restricting access. Radiologists would be the “gatekeepers” of imaging, a concept first introduced by ACR in the early days of managed care as a means of limiting patients’ access to expensive specialty care by giving radiologists control of diagnostic testing, which was to be performed prior to a patient seeing a specialist.

Despite this contentious atmosphere, much common ground exists. Both the American College of Cardiology and the ACR have issued recommendations for training and qualifications needed for competency in cardiac CTA. The recommendations are similar, although ACC requirements to achieve competency are somewhat more rigorous.

There is great demand for training in CTA by both radiologists and cardiologists, particularly for “hands-on” experience in acquiring, processing and interpreting angiograms. Cardiologists and radiologists peacefully mingle at these training opportunities. Implementation of CTA programs at the local level often results in collaboration between cardiologists and radiologists, who share not only expertise but also the use of limited imaging resources.

Shared responsibility

An area of responsibility often shared between cardiologists and radiologists is the interpretation of abnormalities present in nonvascular structures. CT has particular features, including exposure to a significant dose of radiation and the capacity to produce high quality images of nonvascular structures from the same data set used to produce angiograms, which make it reasonable to report on abnormalities, such as lung nodules, which were not the primary reason for performing the examination.

Although striking abnormalities are regularly detected in individual patients, in aggregate, the clinical value of reporting these nonvascular abnormalities has not been proven, as the costs, complications and benefits of further evaluation and treatment of detected abnormalities has not been quantified. Many cardiologists are comfortable providing “screening” interpretations of these ancillary findings, while others prefer to have radiologist over-read the images for nonvascular abnormalities.

Coverage policies

The ACC and the ACR have collaborated with the American Medical Association and cardiology subspecialty societies on new CPT codes that accurately describe various aspects of cardiac and vascular CT angiograms. The ACC and ACR are also working together to create a model coverage policy related to CTA for Medicare carriers.

A resolution recently passed by the American Medical Association House of Delegates encouraged pursuit of quality imaging based on objective measures of competence and appropriateness, regardless of specialty providing the service.

The ACC is vigorously pursuing comprehensive programs to provide utilization guidelines, evidence-based indications, appropriateness standards and performance measures for CTA and other diagnostic and treatment modalities. Working together with its related subspecialty organizations, insurance carriers, CMS, employers, health care managers and others, the ACC will develop an objective, evidence-based framework within which the clinical value and cost effectiveness of CTA can be measured.

Utility of CTA

The utility of CTA is also becoming widely appreciated by physicians who care for patients with vascular disease. These specialists are employing CTA alongside ultrasound and MRI to evaluate carotid disease, renal artery and peripheral stenosis and aortic aneurysms. Electrophysiologists are using CTA to guide ablations and placement of biventricular pacemakers. Emergency room physicians are starting to use CTA to rapidly exclude the presence of coronary disease in patients presenting to them with chest pain but low to intermediate likelihood of coronary artery disease.

The specter of easy 24/7 availability of on-demand CT coronary angiography in the emergency room raises additional questions about who will interpret these images. Nuclear medicine physicians are interested in CTA not only because CTA threatens to replace some indications for nuclear imaging with stress testing, but also because CTA images can be fused with nuclear perfusion images to provide increased resolution and valuable information about both structure and function.

CTA is a powerful and robust new technology, exciting to many different physician specialists. It seems unlikely that its use will be restricted to the hospital radiology department or its interpretation limited to radiologists.

Samuel Wann, MD, is chairman, department of cardiovascular medicine, Wisconsin Heart Hospital, Wauwatosa. He is editor of Cardiology Today’s Health Policy, Patient and Practice Issues section.