Feature | March 22, 2007| Jeffrey J. Fine, M.S., Ph.D. with contributions from Timothy W. Attebery

Get Ready for a Paradigm Shift

Reviewing the profound impact of coronary CT angiography on cardiology

Siemens' Somatom Definition is the world's first Dual-Source CT scanner.

Siemens' Somatom Definition is the world's first Dual-Source CT scanner.

Diagnostic cardiology has experienced revolutionary changes over the past five years as a result of coronary computed tomography angiography (CCTA). The ability to noninvasively obtain three- dimensional anatomic images of technical quality far superior to catheter angiography has forever altered the diagnostic landscape.
With dramatically faster acquisition times and reduced slice thickness, multislice CT scanning has entered a new era. As the technical performance of the cardiac CT scanner has improved, the window of potential patients has predictably expanded.
As recently as five years ago, a symptomatic patient with mild or moderate risk of coronary artery disease would typically undergo nuclear perfusion testing as the first diagnostic test. If the nuclear study was abnormal the patient would, by default, arrive in the catheterization lab for an invasive and very costly procedure.
Data has suggested that nearly 24 percent of nuclear perfusion studies yield an equivocal result. In the absence of a CCTA program, the majority of these patients progressed to the diagnostic catheterization lab as a precaution to rule out coronary artery disease. Today many of these equivocal nuclear studies are being redirected to CCTA as a dramatically less expensive, noninvasive alternative with equally high negative predictive values for ruling out disease.
Data suggests that a very large percentage of patients today are encountering a CCTA study as the initial diagnostic procedure in lieu of a nuclear perfusion study.
Preliminary results from the CCTA Data Registry, which holds over 20,000 cases, show that 69 percent of CCTA cases are substitutions for nuclear perfusion testing as the initial diagnostic test. Furthermore, with CCTA being reimbursed at a lower rate than either nuclear perfusion testing or diagnostic catheterization, whenever a substitution occurs the healthcare system realizes a savings. Among the cases included in the CCTA Data Registry, the mean savings per diagnostic episode on a per- patient basis was $442.
Preliminary results from the CCTA Data Registry show the substitutions that have occurred after the implementation of 64-slice CCTA. Nuclear perfusion testing volumes declined by an average of eight percent and diagnostic catheterizations declined by five percent after initiating a CCTA program. Data also suggests that diagnostic catheterizations that produce a “normal” result declined on average by six percent post-CCTA implementation. This may be attributable to having a suitable alternative to catheter angiography for mild or moderate risk patients.
More Opportunities
Beyond the economic benefits inherent in a CCTA program due to substitutions for more expensive tests lie increased disease management opportunities.
Because of the noninvasive and more patient-friendly nature of CCTA, practitioners are realizing an opportunity to identify subclinical disease permitting early stage disease management previously unavailable. To moderate risk patients with atypical symptoms, CCTA presents details of their early stage disease as never seen before. This information permits disease management that may prevent disease advancement to clinically significant lesions or acute events.
As a result, CCTA is creating a paradigm shift within cardiology. The clinician of today is moving away from “lesionology” and, as a result of having detailed disease data at the subclinical level, is moving toward a disease stabilization or even regression mindset.
Transitioning a “Disruptive Technology”
Currently in the U.S., providers of cardiovascular services (e.g., cardiology groups, hospitals, heart centers, heart hospitals) have significant investments in SPECT cameras and catheterization laboratories. This investment is not simply financial (equipment, space, software, etc.) but also an investment in physician competency, organizational knowledge and general workflow. In addition, health insurance companies, health plans, managed care companies and healthcare payors have invested in organizing, administering and optimizing the current system. The introduction of any new approach, regardless of validation and promise supporting it, will not be synthesized smoothly or quickly into this system of established CV providers and payors.
CCTA is following the traditional pathway of other “disruptive technologies.” After some early success from the “pioneers,” disruptive technologies usually incur a period of time during which there are setbacks and delays in progress.
As the adoption of the disruptive technology moves beyond the early zealots to the real-world skeptics, the pace of integration slows. Eventually these hurdles are addressed and resolved. The system realigns around the disruptive technology after full, undeniable evidence emerges demonstrating the overall value or superiority of the new approach. This opens up an accelerated rate of adoption and the disruptive technology becomes generally entrenched throughout the system.
Moving Closer to Widespread Adoption
No one can predict the pace of CCTA adoption in the U.S. during the next 12 to 24 months. However, based upon our knowledge of the provider and payor market, we believe we are in the final stage of resistance to widespread clinical adoption of and reimbursement for CCTA.
All but one Medicare Part B intermediary have published or are in the final stages of publishing an LCD (local coverage determination) for CCTA. Several national radiology benefits management companies are working on their CCTA policies. UNITED has a CCTA policy and several other national health insurance companies are in the early stages of formulating their CCTA policies — 2007 will be the turning point for provider and payor adoption of CCTA.
During 2007 and the first half of 2008, the number of cardiologists and radiologists trained to interpret CCTA will increase rapidly. We estimate that by July 1, 2008, there will be over 5,000 cardiologists with Level 2 CCTA status (qualified to interpret CCTA) and another 5,000 with Level 1 CCTA status (qualified to order CCTA exams). As more physicians are trained to order/interpret, and as more payors establish CCTA reimbursement policies, the number of CCTA exams will increase significantly.
From early 2008 and onward, the general availability and utilization of CCTA will reach nearly every metropolitan and micropolitan statistical area in the U.S. We predict that the adoption curve will accelerate in 2008 and continue at this accelerated rate for several years until leveling off. By 2011, CCTA will position itself as the primary test for coronary anatomy evaluation.
During the next five years, MSCT and workstation manufacturers will continue their improvements and upgrades in the various hardware and software components. Radiation exposure will greatly decrease. Heart-rate control will become less important as temporal resolution improves. The use of CCTA pre-PCI, pre-CABG and prior to certain EP procedures will expand. The number of diagnostic cardiac catheterizations will likely decrease as the catheterization lab shifts more toward an “interventional” service.
Despite many hurdles to overcome, CCTA has momentum in the provider community. Payor resistance will be resolved as data clearly demonstrates the cost-effectiveness of CCTA. The bottom line is this: CCTA provides images and data that no other modality can deliver in a cost-effective and patient-friendly manner. CCTA fills a void that has existed for many years and will reach a high level of adoption in the next five years.

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