SAN FRANCISCO – A new report compiled by eight cardiology and imaging specialty organizations updates 4-year-old recommendations on when to use (or not use) cardiac CT imaging.
The eight societies hope that the recommendations will help inform clinicians and patients who are considering cardiac CT and also will guide insurers and third-party payers in setting rational reimbursement policies for cardiac CT.
The report, released by the American College of Cardiology, was endorsed by the ACC Foundation, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance.
The appropriate use criteria cover two tests: cardiac CT angiography using contrast, x-ray, or dye; and noncontrast CT scanning for calcium scoring, used to detect calcium deposits in the arteries (J. Am. Coll. Cardiol. 2010 Oct. 25 [doi: 10.1016/j.jacc.2010.07.005]).
CT angiography was considered appropriate for diagnosis and risk assessment in patients with symptoms of possible heart disease who have a low to intermediate risk of a heart problem, or in situations where the diagnosis of heart disease is uncertain after other tests are performed.
Calcium scanning was considered appropriate in patients without heart symptoms who have an intermediate risk of heart disease, or in selected patients with low risk (especially women or younger men) with a family history of heart problems.
Cardiac CT would not be appropriate for general screening in asymptomatic patients, or in patients with known heart problems or a high risk for heart disease, or for routine repeat testing, the report concludes. Adding the test when patients have high risk for heart disease or existing heart problems does not add any useful clinical information, Dr. Allen J. Taylor said in a statement released by the ACC. Dr. Taylor is chair of the report's writing committee and professor of medicine at Georgetown University, Washington.
The report also judged the usefulness of cardiac CT to be “uncertain” in some clinical scenarios, and the authors emphasized repeatedly that this does not mean that the test is inappropriate or that insurers should not reimburse for its use in these situations. An “uncertain” indication may require individual physician judgment and understanding of the patient to decide whether cardiac CT might help.
Tables in the report list 60 indications deemed appropriate, 52 rated as uncertain, and 55 considered inappropriate for cardiac CT. Clinical scenarios included acute and chronic chest pain, testing in symptomatic and asymptomatic patients, heart failure, preoperative risk assessment before either cardiac or noncardiac surgery, testing in the setting of prior test results (such as exercise testing, stress imaging procedures, or coronary calcium scores), prior revascularization, and evaluation of cardiac structure and function.
The document replaces the original 2006 criteria that were created when cardiac CT was relatively new (J. Am. Coll. Cardiol. 2006;48:1475-97).
The process to create the new criteria combined evidence-based medicine and practice experience. A seven-member writing group developed clinical scenarios that were scored by a 19-member technical panel on a 1-9 scale to reflect their judgements of appropriate use of cardiac CT, inappropriate use, or uncertainty about the appropriateness of use.
In the real world, no physicians or facilities will have 100% of their cardiac CT procedure fall within the “appropriate” indications, the report notes. But if a physician or facility has a higher rate of inappropriate procedures than the national average, they may want to examine their patterns of care.
For the first time, the report considered CT angiography in patients with heart failure and normal, as well as abnormal, left ventricular ejection fraction (LVEF), with ratings of appropriate or uncertain. The only appropriate scenarios covered patients with reduced LVEF who had low or intermediate pretest probability of coronary artery disease.
CT angiography was considered a potential option as part of preoperative evaluations for patients undergoing heart surgery for noncoronary indications such as valve replacement, and was considered appropriate in patients with intermediate pretest risk for coronary artery disease, and of uncertain appropriateness if the pretest risk was low. Coronary CT angiography was never considered appropriate for evaluations before noncardiac surgery.
Imaging for evaluation of left main coronary stents was deemed appropriate, and was considered uncertain for any coronary stents measuring 3 mm in diameter or larger that had been in place at least 2 years.
The evaluation of cardiac structure and function is considered a strength of cardiac CT imaging. For the first time, the report rated cardiac CT as appropriate in patients with suspected arrhythmogenic right ventricular dysplasia, and as uncertain for evaluation of myocardial viability when other imaging modalities are inadequate or contraindicated.