Efficacy of SCS in Severe & Refractory Angina Pectoris
A few large long-term follow-up studies exist on treatment of severe and refractory angina pectoris with SCS. The available studies indicate that SCS treatment is associated with symptom relief and improvement of quality of life.[16,17,34] The beneficial effects of SCS seem to persist after long-term treatment, up to 5 years after implantation according to available studies.[16,17,34] In recent years a systematic review and a meta-analysis on the efficacy of SCS in severe angina pectoris, have been published.
A systematic literature search, covering the years 1966–2003, carried out as part of the Swedish Council on Health Technology Asessment (SBU) report on long-standing pain, was supplemented by additional research covering the years 2003–2007 by Borjesson et al.. Acute studies, case reports, mechanistic studies and reviews were excluded, leaving 44 studies that were graded for study quality according to a modified Jadad score. The eight medium- to high-score studies formed the basis for conclusions regarding scientific evidence (strong, moderately strong or limited) for the efficacy of SCS.[25,37–43] These include the Electrical stimulation versus Coronary artery Bypass Surgery in severe angina pectoris (ESBY) study which was a randomized, prospective study including patients with increased surgical risk and no prognostic benefit from revascularization. The main result of the study was that SCS was equally effective as CABG in relieving symptoms of these heavily-symptomatic patients, at a lower complication rate, at 6 months. In the Spinal Cord Stimulation Versus Percutaneous Myocardial Laser Revascularization In patients With Refractory Angina Pectoris Trial (SPiRiT), SCS was compared with PMR for patients with refractory angina pectoris, in a single-centre study, in a randomized controlled fashion (n = 68), and was found to be equally effective and safe.
In summary, the authors found strong evidence in the literature for SCS giving rise to symptomatic benefits (decrease in anginal attacks) and improved quality of life, in patients with severe angina pectoris. There was also strong evidence for SCS improving the functional status of patients with refractory angina, as illustrated by improved exercise time on treadmill or longer walking distance without angina. In addition, there was small amount of scientific evidence that SCS does not seem to have any negative effects on mortality in patients with refractory angina pectoris and the complication rate was found to be low.
In a recent study, by Lanza et al., 25 patients with rheumatoid arthritis, who had never received SCS before, were randomized to three groups; paresthesia, subliminal stimulation and sham stimulation. Regular stimulation, but not subliminal SCS, was superior to sham SCS in improving clinical status (anginal attacks, nitroglycerin use, quality of life score and angina class) in refractory angina patients.
Despite the effects of SCS, some patients are nonresponders to the treatment, the most common reasons, in our experience, being: in patients where psychosocial factors are the main determinants of symptoms, in patients where the pain is secondary to other disorders, for example gastroesophageal reflux or post-thoracotomy pain, or due to device failure secondary to technical failure or anatomical reasons.
Future Cardiol. 2011;7(6):825-833. © 2011 Future Medicine Ltd.
Cite this: Spinal Cord Stimulation for Long-term Treatment of Severe Angina Pectoris - Medscape - Nov 01, 2011.