News
The controversial 2013 American Heart Association/American College of Cardiology guideline on the assessment of cardiovascular risk matches statin use to patients’ total plaque burden better than did its predecessor, the 2001 National Cholesterol Education Program Adult Treatment Panel III recommendation, according to a retrospective study published online Aug. 25 in the Journal of the American College of Cardiology.
Dr. Kevin M. Johnson
The new guideline assigned statins to more patients who had high plaque burden and fewer patients with no identifiable plaque while increasing overall statin assignment by 15%. The new guideline met considerable resistance on its release, with warnings that statins would be overused and that the tool used to calculate the 10-year probability of an atherosclerotic cardiovascular event overestimated the risk by 75%-150% (Lancet 2013;382:1762-5).
In the study, which involved 3,076 adults who underwent CT angiography in a 5-year period at a single private outpatient radiology practice, the probability that each patient would be prescribed statin therapy was calculated using both the newer guideline on the assessment of cardiovascular risk (J. Am. Coll. Cardiol. 2014;63:2889-934) and the older ATP III recommendations (JAMA 2001;285:2486-97). This probability was then matched to each patient’s actual burden of coronary atherosclerosis, as measured by the CT angiography.
The ACC/AHA guideline outperformed the ATP III guideline substantially at appropriately matching statin therapy with actual plaque burden, said Dr. Kevin M. Johnson of the department of diagnostic radiology at Yale University, New Haven, and Dr. David A. Dowe of Atlantic Medical Imaging in Galloway, N.J.
Among all patients who proved to have heavy plaque, 92% would have been advised to use statin therapy according to the 2013 ACC/AHA guideline, compared with only 53% who would have been advised to use statin therapy according to ATP III. At the same time, among patients found to have no plaque or only trace levels of plaque, fewer would have been prescribed statin therapy according to the ACC/AHA guideline (36%) than according to the ATP III recommendations (41%).
"Of note, under the [ATP III] guideline, 59% of the patients with 50% or greater stenosis of the left main coronary artery and 40% of patients with 50% or greater stenosis of other branches would not have been treated [with statins]. The [respective] results for the [ACC/AHA guidelines] were 18% and 10%," the investigators said (J. Am. Coll. Cardiol. 2014 Aug. 25 [doi:10.1016/j.jacc.214.05.056]).
Overall, 15% more patients would have been assigned statins under the new guideline than with ATP III. This "modest" increase is in line with projections by the ACC/AHA Task Force on Practice Guidelines.
"On the basis of our findings, it is a reasonable hypothesis that the new guideline will better predict coronary events, given that it better correlates with the severity of underlying atherosclerosis," Dr. Johnson and Dr. Dowe noted.
Dr. Johnson and Dr. Dowe reported no relevant financial conflicts of interest.
