The Effect of Statin Therapy on Coronary Plaque Composition Using Virtual Histology Intravascular Ultrasound: A Meta-Analysis

OBJECTIVE: Previous studies have indicated that statin therapy may promote plaque regression. However, the impact of statin therapy on plaque composition has not been clearly elucidated. We performed a meta-analysis to investigate the effect of statin therapy on coronary plaque composition as assessed by virtual histology intravascular ultrasound (VH-IVUS). METHODS: Online databases were searched from inception to March 1, 2015. Studies providing VH-IVUS volumetric analyses of coronary plaque composition at baseline and follow-up in patients receiving statin therapy were included. Weighted mean difference (WMD) using a random-effects model was used. RESULTS: Ten studies involving 682 patients were included. There was a substantial reduction in fibrous volume between baseline and follow-up (WMD: -2.37 mm(3), 95% confidence interval (CI) -4.01 to -0.74 mm(3), P=0.004), and a significant increase in dense calcium (DC) volume (WMD: 0.89 mm(3), 95% CI 0.70 to 1.08 mm(3), P<0.00001). No significant change was seen in fibro-fatty and necrotic core (NC) volumes. In stratified analyses, the fibrous volume was decreased significantly (WMD: -3.39 mm(3), 95% CI -6.56 to -0.21 mm(3), P=0.04) and the absolute DC volume (WMD: 0.99 mm(3), 95% CI 0.23 to 1.76 mm(3), P=0.01) was increased in the subgroup with ≥12 months follow-up, whereas no significant change was observed in the subgroup with < 12 months follow-up. Similarly, a substantial decrease in fibrous volume (WMD: -2.01 mm(3), 95% CI -3.05 to -0.96 mm(3), P< 0.0002) and an increase in DC volume (WMD: 0.90 mm(3), 95% CI 0.70 to 1.10 mm(3), P< 0.00001) were observed in the subgroup with high-intensive statin therapy, while the change in fibrous and DC volumes approached statistical significance (P=0.05 and P=0.05, respectively) in the subgroup with low-intensive statin therapy. CONCLUSIONS: Statin treatment, particularly of high-intensity and long-term duration, induced a marked modification in coronary plaque composition including a decrease in fibrous tissue and an increase in DC.