Abstract 554: Prediction of Coronary Artery Disease by a Whole-Body Magnetic Resonance Angiography Derived Systemic Atherosclerosis Score Index
Background: Whole-body magnetic resonance angiography (WB-MRA) has shown its potential for the non-invasive assessment of nearly the entire arterial vasculature within one examination. Since the presence of extra- cardiac atherosclerosis is associated with an increased risk of coronary events, our goal was to establish the relationship between WB-MRA findings, including a newly developed systemic atherosclerosis score index, and the presence of significant coronary artery disease (CAD).
Methods: WB- MRA was performed on a 1.5T scanner (Intera Achieva®, Philips Medical Systems) in 50 patients scheduled to undergo elective cardiac catheterization for suspected CAD. In each patient, 40 extra- cardiac vessel segments were evaluated and assigned scores according to their luminal narrowing. The atherosclerosis score index (ASI) was generated as the ratio of summed scores to analyzable segments.
Results: ASI was higher in patients with significant (> 50% stenosis) CAD (n= 27) vs. patients without CAD (n= 22; 1.77 vs. 1.33, p= 0.003). ASI correlated well with PROCAM (R= 0.76, p< 0.001) and Framingham (R= 0.46, p= 0.001) risk scores as estimates of the 10-year risk of coronary events. A ROC derived ASI of > 1.72 predicted significant CAD with a sensitivity of 59%, specificity of 91% and a positive predictive value of 89%. Logistic regression revealed the ROC optimized ASI cut- off as the strongest independent predictor for CAD with a 20-fold increase in likelihood to suffer from significant coronary disease. While 55% of patients with CAD had at least one higher- grade (> 50%) extra-cardiac stenosis, only 14% of patients without CAD did (p= 0.003). On the contrary, 15/18 (83%) patients who showed a higher-grade extra-cardiac stenosis also suffered from significant CAD.
Conclusions: This study provides important new evidence for the close association of extra-cardiac and coronary atherosclerosis. The novel findings that a WB-MRA derived systemic atherosclerosis score index is not only associated with established cardiovascular risk scores but is also predictive of significant CAD suggest its potential prognostic implications and underline the importance to screen for coronary disease in patients with extra-cardiac manifestations of atherosclerosis.