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A coronary artery calcium scan should be the go-to test for cardiovascular screening of asymptomatic patients with type 2 diabetes older than 40, followed by an exercise stress test for high scores, a report from the American College of Cardiology (ACC) concluded.

New evidence suggests that diabetes is not necessarily a coronary heart disease risk equivalent as was previously thought -- 25% to 30% of patients with diabetes are actually at low cardiovascular risk, said lead author of the report, , of the University of California Los Angeles, and colleagues on the ACC's Imaging Council.

A diabetic patient's actual risk depends on other factors, including gender, the presence and extent of atherosclerosis, additional risk factors, clinical symptoms, and chronic kidney disease, Budoff and colleagues said in the .

"New guidelines have started to acknowledge the heterogeneity in risk and include different treatment recommendations for diabetic patients without other risk factors who are considered to be at lower risk," they wrote. "Furthermore, guidelines have suggested that further risk stratification in patients with diabetes is warranted before universal treatment."

"By properly evaluating the level of coronary heart disease risk, physicians will know when to prescribe more aggressive and less aggressive treatment strategies for their patients," Budoff said in a statement. "While more recent data indicates the risk of coronary heart disease for people with type 2 diabetes is less than was previously believed, it is still critical for physicians to properly assess risk and provide the appropriate strategies of care."

To help doctors better assess cardiovascular risk in patients with diabetes, Budoff and colleagues reviewed the available evidence on non-invasive testing for risk-stratification in asymptomatic diabetes patients, including coronary computed tomography, radionuclide imaging, echocardiography, and other tests.

The report authors concluded by offering a simple algorithm: individuals with diabetes who are older than 40 and have no cardiovascular symptoms may benefit from a coronary artery calcium scan. If the coronary artery calcium score is higher than 400, an exercise stress test imaging study should be considered.

"This writing group represents that, at present, coronary artery calcium screening offers the most sensitive noninvasive risk stratification tool among asymptomatic persons with diabetes mellitus. Coronary artery calcium imaging currently has a Class IIa recommendation for screening in this population from ," Budoff and colleagues said.

"Functional stress testing may further refine risk estimation in asymptomatic patients with diabetes mellitus who have a high coronary artery calcium. The available data suggest that this might result in a future recommendation for coronary artery calcium screening in type 2 diabetes, followed by functional testing for ischemia in patients with a pre-determined coronary artery calcium threshold," they suggested.

"However, although this approach has been shown to improve the stratification of persons with diabetes mellitus, it has not yet been shown to result in improved outcomes. This is a knowledge gap that needs to be addressed with clinical trials," they acknowledged.

So should all diabetic patients older than 40 be screened with a coronary artery calcium test?

"The answer is no, coronary artery calcium should not be routine in asymptomatic patients with diabetes mellitus over 40, at least not yet," said , of the University of Colorado Anschutz Medical Campus in Aurora, Colo., in an email to 麻豆传媒.

"Even though asymptomatic diabetes mellitus is not a coronary heart disease risk equivalent, statin therapy should be given to reduce atherosclerotic cardiovascular events in patients with diabetes between the ages of 40 and 75 -- this is evidence-based and stated ," Eckel said.

"Yet, in those patients younger than 40 or over 40 without added risk beyond diabetes, the health care practitioner is often uncertain, and in this setting the coronary artery calcium score could be a tie-breaker to treat or withhold treatment," Eckel said. "If the latter decision is made, it would not be consistent with the guideline, but again this could all change with more imaging data to come."

"In general, additional cardiac workup is debatable, and I think Budoff et al. would agree," Eckel said. "Although there is a greater likelihood of ischemia and/or events with coronary artery calcium >400 in patients with or without diabetes, there is no evidence that a more aggressive workup or intervention decreases events or save lives."

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