Spinal cord stimulation in refractory angina. A systematic review of randomized controlled trials

Spinal cord stimulation (SCS) is an invasive method used for treating patients with refractory angina. Although SCS is recommended by the European Society of Cardiology and American Heart Association (class lib, level of evidence B and C, respectively), the method is used very rarely and data on its effectiveness is limited. The aim of this work was to perform a systematic review of all randomized controlled trials (RCTs) that investigated the effectiveness of SCS as a treatment for refractory angina.

Medline and Cochrane library databases were searched from their inception to April 2014 for RCTs that investigated the efficacy and safety of SCS in patients with refractory angina.

Nine RCTs were included in the systematic review. The included RCTs were categorized into two groups: RCTs comparing SCS either with optimal medical treatment or inactive mode or low stimulation SCS; and those comparing SCS with alternative therapeutic interventions. Follow-up was short-term (1-6 months) in most studies, showing no major complications. Two studies reported a neutral effect regarding mortality. Regarding efficacy, most RCTs were in favour of SCS mainly in the short term. The most recent, multi-centre RCT reported no significant difference compared to the control group.

RCTs investigating the efficacy of SCS were small and they demonstrated a small effect in angina improvement. Due to great differences in their design the interpretation of the results is complex. Before this method is recommended as a routine therapy for refractory angina, a larger, well-designed, multicentre RCT is needed.