title: Temporary sympathectomy in chronic refractory angina: a randomised, double-blind, placebo-controlled trial.
abstract: BACKGROUND
  Temporary sympathectomy by injection of bupivacaine at the site of the left stellate ganglion is used in the management of refractory angina at several UK centres. Although patients frequently report significant reduction in symptoms, efficacy has not been established by double-blind, randomised placebo-controlled trial (RCT).
  
  
  OBJECTIVE
  To investigate the efficacy of the procedure for the first time by a double-blind RCT.
  
  
  METHODS
  Consecutive patients referred to the authors' National Health Service (NHS) angina centre who were candidates for temporary sympathectomy were invited to participate in a trial. A total of 65 patients were randomised to receive either bupivacaine or saline injections. Identical syringes were prepared remotely, blinding patients and staff from randomisation. Cardiac autonomic function was measured 3 hours pre- and post-injection using new heart rate variability (HRV) analyses. Angina episodes were recorded contemporaneously by patients in study diaries in the 7-day periods pre- and post-injection.
  
  
  RESULTS
  In 51 patients suitable for analysis, no significant differences between the active and placebo groups were found in patient-recorded frequency or intensity of angina episodes pre- and post-injection. However, across both groups combined, a significant difference was found in the frequency of angina episodes pre- and post-injection.
  
  
  CONCLUSIONS
  The reduction in frequency of angina episodes produced by this procedure may not be due to drug pharmacology. It may be a placebo response or due to the mechanical effects of the injection of fluid. There is a need for further work using a larger patient cohort considering both mechanical and psychological factors.
authors.affiliation: Department of Medical Physics and Clinical Engineering, Royal Liverpool and Broadgreen University Hospitals NHS Trust (RLBUHT), Liverpool, UK.
authors.forename: Christine
authors.initials: C
authors.lastname: Denby
authors.affiliation: Department of Medical Physics and Clinical Engineering, Royal Liverpool and Broadgreen University Hospitals NHS Trust (RLBUHT), Liverpool, UK.
authors.forename: David G
authors.initials: DG
authors.lastname: Groves
authors.affiliation: Department of Medical Physics and Clinical Engineering, Royal Liverpool and Broadgreen University Hospitals NHS Trust (RLBUHT), Liverpool, UK.
authors.forename: Antonio
authors.initials: A
authors.lastname: Eleuteri
authors.affiliation: Liverpool Angina Management Programme, Royal Liverpool and Broadgreen University Hospitals NHS Trust (RLBUHT), Liverpool, UK ; Department of Anaesthesia, Royal Liverpool and Broadgreen University Hospitals NHS Trust (RLBUHT), Liverpool, UK.
authors.forename: Hoo Kee
authors.initials: HK
authors.lastname: Tsang
authors.affiliation: Liverpool Angina Management Programme, Royal Liverpool and Broadgreen University Hospitals NHS Trust (RLBUHT), Liverpool, UK ; Department of Anaesthesia, Royal Liverpool and Broadgreen University Hospitals NHS Trust (RLBUHT), Liverpool, UK.
authors.forename: Austin
authors.initials: A
authors.lastname: Leach
authors.affiliation: Liverpool Angina Management Programme, Royal Liverpool and Broadgreen University Hospitals NHS Trust (RLBUHT), Liverpool, UK ; Department of Cardiology, Whiston Hospital, St Helens and Knowsley Hospitals NHS Trust, Prescot, UK.
authors.forename: Clare
authors.initials: C
authors.lastname: Hammond
authors.affiliation: Liverpool Angina Management Programme, Royal Liverpool and Broadgreen University Hospitals NHS Trust (RLBUHT), Liverpool, UK.
authors.forename: John D
authors.initials: JD
authors.lastname: Bridson
authors.affiliation: Liverpool Angina Management Programme, Royal Liverpool and Broadgreen University Hospitals NHS Trust (RLBUHT), Liverpool, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Fisher
authors.affiliation: Department of Medical Physics and Clinical Engineering, Royal Liverpool and Broadgreen University Hospitals NHS Trust (RLBUHT), Liverpool, UK.
authors.forename: Matthew
authors.initials: M
authors.lastname: Elt
authors.affiliation: Department of Medical Physics and Clinical Engineering, Royal Liverpool and Broadgreen University Hospitals NHS Trust (RLBUHT), Liverpool, UK.
authors.forename: Robert
authors.initials: R
authors.lastname: Laflin
authors.affiliation: Department of Medical Physics and Clinical Engineering, Royal Liverpool and Broadgreen University Hospitals NHS Trust (RLBUHT), Liverpool, UK ; Department of Physics, University of Liverpool, Liverpool, UK.
authors.forename: Anthony C
authors.initials: AC
authors.lastname: Fisher
keywords: Gaussian process; Lomb–Scargle; Stellate; angina; heart rate variability; palliative treatment; randomised placebo-controlled trial