Abstract 10137: Low-Density Lipoprotein Cholesterol is Poor Predictor of Effective Therapy as Measured by Carotid Plaque Necrotic Core Size After > 1 Year Statin Therapy
Introduction: While stroke-related mortality has been decreasing, further reductions may require monitoring of individual response to therapy over and above existing risk factors such as hyperlipidemia. Measurement of lipid rich necrotic core size by carotid plaque MRI can provide this additional information. Larger necrotic core size has been correlated with intraplaque hemorrhage, development of fibrous cap rupture, as well as future stroke and TIA. It is unclear if blood lipid level is a true reflection of plaque lipid contents.
Hypothesis: Even though there is an overall reduction of plaque lipid levels with statin therapy, the overall long term relationship between plaque lipid rich necrotic core and blood lipid level may not be strongly correlated.
Methods: Thirty consecutive patients (17 men, 13 women) recruited as part of 3T MR carotid plaque study of asymptomatic patients with >50% stenosis on duplex ultrasound in whom detailed information on statin therapy and lipid profiles is available were included. Two blinded reviewers interpreted multicontrast MRI and measured necrotic core % volume.
Results: Patients were on statin therapy for median 3.2 years and on stable statin therapy for > 1 year in all cases. The median time between lipid profile and MR study was 3 months. No correlation was seen on the scatterplot of LDL-C versus necrotic core % volume. Eleven patients had LDL-C < 70 mg/dL and 19 patients were >70 mg/dL. Of the 11 patients with LDL-C <70, 7 had necrotic core > 5% volume. Of the 19 patients with LDL-C >70, 6 had necrotic core > 5% volume.
Conclusion: In patients judged to have excellent control of hyperlipidemia by statin as measured by LDL-C < 70 mg/dL, 64% demonstrated residual lipid rich necrotic core >5% volume despite statin therapy for a median 3.2 years. Carotid plaque imaging may be able to identify a subgroup of asymptomatic patients with >50% carotid stenosis who might benefit from more aggressive medical therapy that could not be predicted by LDL-C alone.
- © 2011 by American Heart Association, Inc.