Abstract
Objective:
To test the hypothesis that lipid indices have a role in monitoring lipid-rich necrotic core (LRNC) burden and to see if this varies with statin exposure.
METHODS:
Cohort of 73 symptomatic carotid stenosis patients were identified with MR angiogram imaging to assess their carotid LRNC percentage determined by 2 independent radiologists and corresponding lipid profiles . Patients were further stratified into two groups as statin naïve (< 30 day exposure to statin) and term statin group (> 1 month exposure to statin).Simple linear regression was performed between with the dependent variable of LRNC size and independent variables of LDL: HDL ratio, TG :HDL ratio and HDL alone.
RESULTS:
Of 73 patients with LRNC percentage reported 26 were statin naive and 47 were term statin users. Overall LDL:HDL, TG:HDL-C and HDL-C were associated (r,P){moderately(0.37, 0.049)}, {weakly(0.23,0.049)}, {Moderately (-0.30 ,0.01)} LRNC size respectively. Patients with statin naive status, LDL:HDL, TG:HDL-C and HDL-C were associated (r,P){strongly (0.6,0.001)},{not(0.37,0.06)},{Strongly(-0.45,0.02)} with LRNC size respectively. After Stratifying with statin status (Term Statin), LDL:HDL, TG:HDL-C and HDL-C were not associated (r,P) {0.18,0.2),(0.17,0.2),(-0.24,0.1)} with LRNC size respectively. Furthermore, longer duration of statin exposure did not reveal a greater reduction in the size of necrotic core (r=-0.004, P=0.96)(see figure).
Conclusions:
Lipid indices correlate better with carotid plaque morphology in statin naïve patients. After starting statin the same indices correlate poorly with LRNC. Poorly controlled hyperlipidemia is a riskfactor for atherosclerosis, but lack of correlation between LRNC size and lipid levels after patients have been placed on statin therapy suggests the individual patient response to clearing LRNC with statin therapy is heterogenous. Persistent large LRNC with statin may improve lipid but, not the future risk of stroke.