The effects of statin therapy on carotid plaque composition and volume: A systematic review and meta-analysis.

BACKGROUND AND PURPOSE: Prior studies have demonstrated that statin use stabilizes and diminishes atherosclerotic lesions. The main objective of this systematic review and meta-analysis was to study the effects of statin therapy on carotid plaque composition as seen on serial high-resolution carotid plaque MRI. We hypothesized that statin therapy would result in significant improvements in lipid-rich-necrotic-core (LRNC) volumes, wall volumes and lumen volumes.

MATERIALS AND METHODS: Prospective studies using serial high-resolution carotid plaque MRI (1.5 or 3T only) in patients on statin therapy to document changes in carotid plaque composition were included. All studies had a minimum of 10 patients and minimum follow-up duration of 3 months. Outcomes included change in LRNC volume, wall volume, and lumen volume at: (1) 1-6 months; (2) 7-12 months; (3) >12 months following initiation of statin therapy; and (4) at last follow-up. Meta-analysis was performed using the random effects model. Results were reported as weighted mean differences (WMD) and 95% confidence interval (CI).

RESULT: Seven studies including 361 patients were included. There was no significant change in carotid wall volume or lumen volume at any time points. While there was no significant difference in LRNC at 1-6 months and at 7-12 months following initiation of statin therapy; at >12 months, there was significant decrease in LRNC volume (WMD=-9.9mm3 , 95% CI=-8.9, -2.3).

CONCLUSIONS: Our study suggests statin therapy is associated with significant reductions in LRNC at 1-year of statin therapy on serial carotid MRI. However, no significant reduction in carotid wall volume was seen.