Spinal Cord Stimulation in patients with Refractory Angina Pectoris (SCRAP); double-blind, placebo-controlled, cross-over randomized controlled trial

Background Patients with refractory angina pectoris (RAP) remain symptomatic despite maximally tolerated medical therapy and no options for revascularisation, leading to severe restrictions in their daily activities and a decreased quality of life. Objective Spinal cord stimulation (SCS) is one of the treatment options for RAP patients, but there is uncertainty as to the efficacy of SCS. Methods the SCRAP trial is a single centre, cross-over, placebo controlled, double-blinded randomized controlled trial in which patients who meet the criteria for RAP are eligible. Screening was performed with a transcutaneous electrical nerve stimulation treadmill test, and if positive, patients were eligible for an implanted spinal cord stimulator. After implantation, the patient received six months of high density SCS and six months of no stimulation. The primary endpoint of the SCRAP trial was to determine the efficacy of SCS in RAP patients based on the reduction in percentage of myocardial ischemia measured using 82Rb positron emission tomography (PET). Results A total of 28 patients were included in the SCRAP trial. The primary endpoint (% ischemia of left ventricle) was significantly reduced from 9,2 (± 7,7) at baseline to 6,5 (± 7,0) during the six month high density SCS treatment period (p = 0,01). Moreover, key secondary endpoints including the Seattle angina summary score were significantly improved from 38,7 (± 16,6) to 53,8 (± 18,6) (p <0,001). Conclusion RAP patients receiving SCS have a significant reduction in percentage of left ventricular ischemia and a significant improvement in quality of life.