Cerebral Blood Flow Velocity Modulation and Clinical Efficacy of Acupuncture for Posterior Circulation Infarction Vertigo: A Systematic Review and Meta-Analysis

BACKGROUND: Vertigo is a cardinal symptom of posterior circulation infarction (POCI). Acupuncture is demonstrated to have a beneficial effect on posterior circulation infarction vertigo (PCIV). However, the mechanism of acupuncture therapy is not clarified. This study aims to assess the cerebral blood flow velocity modulation and clinical efficacy of acupuncture for PCIV patients. METHODS: We conducted this systematic review for clinical randomized controlled trials (RCTs) regarding acupuncture on PCIV. The study duration was from September 2020 to September 2021. We searched the PubMed, EMBASE, Cochrane Library, Web of Science, Chinese Biomedical Literature Database (CBM), China National Knowledge Infrastructure (CNKI), Wanfang Database, and VIP. The publication date was set from inception to August 31, 2020. Based on the inclusion and exclusion criteria, two researchers independently screened literature and extracted data including basic study information, intervention details, outcome details, and adverse events. Outcome measures included the blood flow velocities of vertebrobasilar arteries and the Clinical Effective Rate of posterior circulation infarction vertigo. Pooled data were presented as standardized mean differences (SMDs) and relative risks (RR), with 95% confidence intervals (CIs). The meta-analysis was conducted using Review Manager software version 5.3.0. RESULTS: A total of 20 eligible RCTs (1541 participants) were included in this review, which compared acupuncture therapy (1 RCT) or acupuncture combined with pharmaceutical therapy (19 RCTs) to pharmaceutical therapy in patients with posterior circulation infarction vertigo. 7 studies assessed the blood flow velocities of the basilar artery examined by Transcranial Doppler (TCD), 8 studies assessed the bilateral vertebral arteries, and 13 studies evaluated the Clinical Effective Rate of posterior circulation infarction vertigo. Meta-analysis results showed that blood flow velocities of the basilar artery (SMD = 0.58, 95% CI = 0.40–0.76; P < 0.05), left vertebral artery (SMD = 0.48, 95% CI = 0.22–0.73; P < 0.05), and right vertebral artery (SMD = 0.44, 95% CI = 0.19–0.69; P < 0.05) were significantly higher in the acupuncture group compared with the control group. Clinical Effective Rate (RR = 1.22, 95% CI = 1.15–1.29; P = 0.792) was significantly better in the acupuncture group compared with the control group. CONCLUSIONS: This study shows that acupuncture therapy is useful in improving the blood flow velocity of vertebrobasilar arteries and Clinical Effective Rate in patients with posterior circulation infarction vertigo. However, double-blind, sham-controlled trials with large sample sizes are required to support our conclusions.