Spinal Cord Stimulation for Refractory Angina Pectoris: A Systematic Review and Meta-analysis

OBJECTIVES: Paresthesia-free stimulation such as high frequency and burst have been demonstrated as effective therapies for neuropathic pain. The aim of this meta-analysis was to evaluate the efficacy and safety of conventional spinal cord stimulation (SCS) in the treatment of refractory angina pectoris (RAP). MATERIALS AND METHODS: Relevant randomized controlled trials that investigated SCS for patients with RAP were comprehensively searched in Medline, Pubmed, Embase, and Cochrane Library. Five meta-analyses were performed examining the changes in Canadian Cardiovascular Society classes, exercise time, Visual Analog Scale (VAS) scores of pain, Seattle Angina Questionnaire, and nitroglycerin use in RAP patients after SCS therapy. We analyzed standardized mean differences (MD) and 95% confidence intervals (CIs) for each outcome by Review Manager 5.0 and STATA 12.0. RESULTS: A total of 12 randomized controlled trials involving 476 RAP patients were identified. A trend of reduction in the angina frequency (MD=−9.03, 95% CI, −15.70 to −2.36) and nitroglycerin consumption (MD=−0.64, 95% CI, −0.84 to −0.45) could be observed in the SCS group. Compared with the control group, SCS showed benefit on increasing exercise time (MD=0.49, 95% CI, 0.13-0.85) and treatment satisfaction (MD=6.87, 95% CI, 2.07-11.66) with decreased VAS scores of pain (MD=−0.50, 95% CI, −0.81 to −0.20) and disease perception (MD=−8.34, 95% CI, −14.45 to −2.23). However, the result did not reach the significance level in terms of physical limitation (95% CI, −8.75 to 3.38; P=0.39) or angina stability (95% CI, −7.55 to 3.67; P=0.50). DISCUSSION: The current meta-analysis suggested that SCS was a potential alternative in the treatment of PAP patients. Further investigation for finding the appropriate intensity of stimulation is required before this treatment should be widely recommended and applied.