Myocardial perfusion after one year of spinal cord stimulation in patients with refractory angina.

Aim: Spinal cord stimulation (SCS) is recommended for patients with coronary artery disease (CAD) and refractory angina. We used positron emission tomography (PET) to investigate the long-term effect of SCS on regional myocardial perfusion in patients suffering from angina pectoris refractory to medical treatment and without option for coronary intervention.

Patients, Methods: We analyzed data of 44 patients with stable CAD (91% three vessel disease). At baseline, we determined coronary flow reserve (CFR) using 13N-ammonia-PET and myocardial viability with 18F-FDG. SCS was performed for one year (Medtronic Itrell III or Synergy, Düsseldorf, Germany). During follow-up, no cardiac interventions were necessary and no myocardial infarctions occurred. At one year follow-up, CFR was measured again.

Results: In the majority of patients (77%), SCS led to an improvement of clinical symptoms. CFR did not change significantly during follow-up. Subjective improvement did not correlate with an increase of CFR.

Conclusions: Despite its clinical effect, SCS does not have a direct impact on CFR in patients with stable CAD. According to our results, the pain relief is not due to an improvement of the myocardial blood supply.