Abstract Body: Background: Intracranial atherosclerosis (ICAS) is a common stroke cause, with a recurrent stroke risk of up to 18% per year despite treatment advances. Although lipid-lowering therapies reduce cardiovascular events, their effect on stroke risk in ICAS remains unclear.
Objective: To perform a systematic review and meta-analysis assessing the efficacy of lipid-lowering therapies in improving stroke outcomes among patients with ICAS.
Methods: A systematic search of PubMed, Embase, Web of Science, Cochrane, and other databases was conducted from inception to November 2023. Eligible studies compared lipid-lowering therapies (Statins and PCSK9i) to standard care or placebo in patients with ICAS. The primary outcome was the incidence of stroke. Pooled relative risks (RR) with 95% confidence intervals (CI) were calculated using a random-effects model, and forest plots were constructed. Chi-square and I 2 statistics were used to assess heterogeneity.
Results: Seven observational studies and two randomized controlled trials involving 1,902 ICAS patients were included. Of these, 801 received lipid-lowering therapy, and 1,101 received standard care or placebo. The weighted mean follow-up was 17.6 months (IQR 9.75-25.5). The weighted mean age was 63.7 years (range 55-68) for the lipid-lowering group and 64.0 years (range 50-66) for controls. Females comprised 42% of both groups. Hypertension was present in 74% of the intervention group and 71% of controls. A history of stroke was reported in 32% of the intervention group and 29% of controls. The weighted mean baseline LDL level was 105 mg/dL in the intervention group and 107 mg/dL in controls. The weighted mean change in LDL pre- and post-treatment in the intervention group was -47.18 mg/dL, compared to -12.39 mg/dL in controls. The incidence of ischemic stroke was 5.0% (40/801) in the lipid-lowering group versus 13.0% (143/1,101) in controls (RR 0.40; 95% CI 0.24-0.64; P<0.001, Figure 1a). Subgroup analysis of studies comparing statin versus no statin treatment showed an RR of 0.40 (95% CI 0.30-0.92; P<0.05, Figure 1b). Another subgroup analysis comparing PCSK9 inhibitors and statins versus statins only found an RR of 0.44; 95% CI 0.20-0.96; P<0.05, Figure 1c).
Conclusions: Lipid-lowering therapies significantly reduce the risk of ischemic stroke in patients with intracranial atherosclerosis. The addition of PCSK9 inhibitors to statins appears to provide added stroke risk reduction.