The use of non-invasive imaging can identify or rule out subclinical atheromatosis and help reduce the number of elderly patients unnecessarily treated with statins without increasing the risk of cardiovascular events.
Using calcium score and carotid ECG to find elderly patients without atheromatosis helps to safely avoid the use of statins with no clinical consequences.
The present study is an attempt to personalize the treatment guidelines for hypolipidemics administration using non-invasive studies, to rule out subclinical disease and to save patients the cost of an expensive treatment that would otherwise be indicated because of age related risk alone.
In 2013, the American College of Cardiology/American Heart Association (ACC/AHA) guidelines extended primary prevention with statins to patients with LDL between 70 and 189 mg/dl and a 10 year risk of ≥ 7.5%.
Given atherosclerosis is associated to old age, most of elderly patients were eligible for statin therapy at the risk of overmedication in a population that already receives to many drugs for other clinical conditions.
The BioImage study included 5,805 patients with no known vascular disease (mean age 69) most eligible for statin therapy (86%) according to 2013 ACC/AHA guidelines.
As part of this study, eligible patients, with $7.5% 10-year disease risk, were down-classified from statin eligible to ineligible when calcium screening and ECG showed no subclinical disease.
Intermediate patients, that is, those with 10 year cardiovascular risk between 5 and 7.5%, were up-classified for statin therapy when imaging showed calcium coronary artery calcium or carotid plaque burden.
Down-classified patients were many, since 32% showed zero calcium score and 23% showed no plaque burden by ECG.
After 2.7 year follow up, 91 patients presented their first cardiac event (infarction, unstable angina or coronary revascularization) and 138 their first cardiovascular event (infarction, unstable angina, coronary revascularization, stroke or vascular disease).
Only three patients with no subclinical disease presented events at follow up.
Risk estimation, according to ACC/AHA guidelines, to decide for statin therapy has high sensitivity (96%) but very low specificity (only 15%) which reflects inability to detect patients without cardiovascular disease.
Using a calcium score of 0 lowers the indication of statin therapy for many patients and increases guideline specificity from 15 to 25% with no significant loss of sensitivity.
The absence of plaque by ECG also increases specificity but with a minor loss of sensitivity.
One of the limitations of BioImage is the short follow up period, but researchers are looking to extending it to 10 years.
Original Title: A simple disease-guided approach to personalize ACC/AHA-recommended statin allocation in people.
Reference: Mortensen MB et al. J Am Coll Cardiol 2016;68:881-891.
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