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- Harvey S. Hecht, MD∗ ()
- ↵∗Reprint requests and correspondence:
Dr. Harvey S. Hecht, Mount Sinai Saint Luke’s Medical Center, 1111 Amsterdam Avenue, New York, New York 10025.
“In the Western world both the proverb and the image are often used to refer to a lack of moral responsibility on the part of people who refuse to acknowledge impropriety, looking the other way or feigning ignorance.”
Consider the following scenario: a 40-year-old male underwent a noncontrast, nongated chest computed tomography (CT) for further evaluation of pulmonary symptoms. Extensive coronary artery calcium (CAC) was present but not reported and statin therapy was not implemented. One year later he died suddenly from a massive myocardial infarction.
Choose the correct answer(s):
1. Catastrophic and potentially avoidable but within the standard of care because reporting CAC on noncontrast CT scans is not part of radiology guidelines.
2. Catastrophic and potentially avoidable but within the standard of care because there are no randomized controlled trials (RCTs) demonstrating that CAC guided treatment affects outcomes positively.
3. Catastrophic and potentially avoidable, and CAC reporting should be routinely reported and incorporated into risk assessment and treatment.
While an obvious oversimplification, this case scenario raises critical issues.
Are professional imaging societies to be held responsible for ensuring that all information in the field of view of their respective images are reported even when RCT evidence for implementation of that information is lacking? If not, does common sense and patient welfare dictate that all actionable findings be reported irrespective of the level of evidence?
In this issue of iJACC, Hughes-Austin et al. (2) provide entrée into these thorny issues. In a nested case study of 157 deaths and 494 controls of 4,544 asymptomatic individuals undergoing both 6 mm noncontrast nongated CT scans and 3 mm noncontrast but gated electron beam CT scans, the correlation coefficient for Agatston CAC scores was 0.93 (p < 0.001); median CAC Agatston scores were lower for the 6 mm scans (22 vs. 104), as would be expected with thicker slices. However, each SD higher CAC score on 6 mm CTs was associated with 50% higher odds of death (odds ratio: 1.5; 95% confidence interval: 1.2 to 1.9), similar to 50% higher odds on the 3 mm electrocardiography-gated CTs (odds ratio: 1.5; 95% confidence interval: 1.1 to 1.9). Similar hazard ratios were noted for CAC categories between the nongated and gated scans: 1.9 and 2.1 for CAC 1 to 100, 2.3 and 2.1 for CAC 101 to 300, and 2.6 and 2.9 for CAC >300. This paper is one of an increasing number that correlate nongated and gated CAC scores but, most importantly, is the first to demonstrate comparable mortalities.
Thus, with minimal effort and no extra radiation, critical prognostic data for the greatest killer in the United States, and increasingly throughout the world, can be extracted from the approximately 7.1 million annual routine, noncontrast CT scans (3). This number will dramatically increase with the 2014 U.S. Preventive Services Task Force endorsed low-dose lung CT scanning for cancer detection, and the 2014 Center for Medicare and Medicaid Services decision to provide coverage for lung scans in a defined high-risk population estimated to be ∼7 million individuals (4). Almost all will be intermediate to high risk for coronary artery disease by standard risk factor based paradigms; in these groups CAC has outcome based net reclassification indices ranging from 52.0% to 65.6% in the intermediate risk, and 34.0% to 35.8% in the high-risk groups (5).
What is the magnitude of the underreporting? There is scant information. In 355 patients with known or suspected coronary artery disease (CAD), CAC was present in 58% of the nongated noncontrast CT scans; 44% of these were unreported. Left main CAC was reported in only 1 of 139 patients and left anterior descending CAC in only 6 of 188 patients with CAC in these vessels (6). In the only other report, CAC >0 was present by expert reader interpretation in 108 of 201 (53%) nongated noncontrast CT scans in patients without suspected CAD, but was reported by the radiologist in only 69% of the 108 positive scans (7).
What are the barriers to reporting? Additional time and effort, not likely to exceed 5 min, are required of the interpreting radiologist. While this may not seem excessive, when multiplied by the number of scans to be read on a daily basis, additional stress will be added to an already overloaded schedule and will not be readily accepted or reimbursed. Reporting very abnormal results to referring physicians who did not request the information and who may not know how it should be utilized may be daunting and consume additional time. Moreover, the referring physicians will be forced to act on, and take responsibility for, results they did not request and may not understand, and they will often need to refer these patients to those physicians capable of implementing the findings into treatment plans. The importance of CAC may not be fully appreciated by the radiology community despite the significant numbers of important CAC articles published in radiology journals, the highlighting of CAC at national and international radiology society meetings and the high positions held by radiologists in the Society of Cardiovascular Computed Tomography. An additional barrier may be the expense of workstations capable of CAC analysis.
From the treatment perspective, the outstanding criticism of CAC has been the absence of RCTs demonstrating a positive effect on outcomes by CAC guided treatment, which has prevented its designation as a screening test by the U.S. Preventive Services Task Force and its reimbursement by insurance companies. In the absence of such trials can one be faulted for not reporting the CAC results or for not implementing them into patient care? If not, then this whole discussion is irrelevant despite the inclusion of CAC in all guidelines, with IIa or IIb recommendations.
Because CAC findings of subclinical CAD are much more frequent than the disease process for which the CT scan was requested to evaluate, particularly lung cancer, and because CAD is the scourge of health care, in all good conscience how can the findings not be reported?
The solutions are straightforward in an ideal world but far more complex in reality:
1. New guidelines by the American College of Radiology and/or the Society of Thoracic Radiology to require reporting of CAC on all noncontrast nongated CT would be appropriate. Simple semiquantitative reporting of none, mild, moderate, or severe CAC would not be time consuming and would be the simplest solution. At the other extreme, Agatston scoring, although preferable, requires more time and CAC analysis software, and may not be acceptable without additional reimbursement. A compromise would employ semiquantitative ordinal scoring which is less labor intensive, requires no software and has documented risk prediction value (8).
2. Intensive education of radiologists and primary care physicians appears warranted, and inventive answers are required to support a pathway toward reimbursement, given the incremental work required to measure CAC. In addition, cardiologists and all referring physicians should also reach out to their radiology colleagues to encourage reading for CAC, particularly in the subset of smoking patients who will be undergoing lung cancer screening.
3. Because there will be millions of CT scans with abnormal CAC results that will need to be incorporated into patient care, the CT ordering physician awareness of the prognostic importance of CAC will need to be increased, irrespective of the physician’s specialty. Simple recommendations, depending on the CAC extent, may be included in the CT report, much as recommendations regarding pulmonary nodules are standard.
4. Expertise in incorporation of CAC into risk assessment and treatment plans will be required of those ordering physicians who will directly implement the information or to whom the patients will be referred by caregivers not comfortable with the decision making. This does not represent an endorsement of CAC for screening. Rather, it is simply acting on findings of critical importance that are present on CT scans ordered for other purposes. In the same manner as a lung mass on a limited field of view CAC scan cannot be ignored, it would be unethical to ignore a high-risk CAC score on a noncontrast CT scan, despite the absence of RCTs.
5. Screening for lung cancer, which always contains the CAC data without extra radiation or cost of acquisition, should be positioned as not just a scan for lung cancer but as an opportunity to detect the early stages of CAD. Moreover, because the aorta is always in the field of view, it would be reasonable to include the detection of thoracic aneurysms as well: a “triple rule out” of a different kind. Given the tortuous, troubled history of lung cancer screening, one can only imagine the controversy a “triple rule out” would create. Yet, it is consistent with reporting all actionable findings, and will need to be addressed sooner or later, preferably sooner.
This approach transforms the problems of dealing with everything in the field of view into an unparalleled opportunity to save lives. As a responsible medical community, we cannot “see no evil” (ignore the CAC), “speak no evil” (not report the results), and “hear no evil” (not listen to and act on the results).
↵∗ Editorials published in JACC: Cardiovascular Imaging reflect the views of the authors and do not necessarily represent the views of JACC: Cardiovascular Imaging or the American College of Cardiology.
Dr. Hecht has served as a consultant to Philips Medical Systems.
- American College of Cardiology Foundation
- ↵Three wise monkeys. Available at: https://en.wikipedia.org/wiki/Three_wise_monkeys. Accessed August 21, 2015.
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- Hecht H.S.