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.
This systematic review demonstrated possible beneficial effects of spinal cord stimulation in refractory angina patients. However, the benefits may be due to increased cardiac blood flow or possibly reduced awareness of the angina. Much more information is needed, and I believe the decision for such a procedure will largely be made by subspecialists and not general internists.
The meta-analysis highlights the lack of evidence supporting electrical spinal cord stimulation for refractory angina pectoris in the patient-centered domains of physical limitation and angina stability. I do not believe this article will change any clinician's practice (i.e., considering this option after exhausting all other options to manage a patient's chest pain).
Although the authors are to be commended for their hard work, the meta-analysis includes studies from the 1990s. During this period of time, there were no strong antiplatelets like clopidogrel, prasugrel, or ticagrelor and no ranolazine to be evaluated. It is also unlikely that high-intensity station therapy was available either. Thus, there are many modern noninvasive treatments that have not been compared with this invasive treatment.
SCS has a limited impact on angina and the evidence base is weak.
As a hospitalist. I believe this is something we rarely think about. It's an impressive study for alternate options for refractory angina. I agree with more studies. Cost effectiveness and LOS has not been analyzed and I am glad that author mentioned about it being the drawback on this study. Even though this option for angina pain seems to be promising with this meta-analysis, I am not convinced about the future of this intervention in near future. I agree with more studies and more data and more emphasis on cost analysis too.