Angina: spinal cord stimulation was as good as and safer than CABG in high surgical risk patients.

Clinical bottom line (level 1b)

  1. In patients with severe angina who would only benefit symptomatically from CABG, but are at increased risk of complications, spinal cord stimulation was as effective at improving symptoms as CABG.
  2. Fewer patients given spinal cord stimulation died (NNT = 8 at 6 months) .
  3. The effect on non-fatal cardiac events was unclear.
Mannheimer et al: Circulation 1998; 97: 1157-1163
Expires June 2003

The study

Unblinded concealed randomised trial with intention-to-treat
Setting: university hospital, Sweden

104 patients (aged range 40 to 82 years; mean 69, 80% male) severe angina who were considered to have only symptomatic indication for coronary artery bypass grafting (CABG), but were at increased risk of surgical complications and unsuitable for percutaneous transluminal coronary angioplasty (PTCA)

Excluded if
  • diffuse extensive disease or chronic multiple stenoses
  • unsuitable for CABG or unable to manage a spinal-cord stimulator
  • MI within six months


    • Control Group: (n = 51, 51 analysed): coronary artery bypass surgery
    Experimental Group: (n = 53, 53 analysed): spinal-cord stimulation surgery- performed under local anaesthetic: electrode inserted at T6 and placed at T1-T2 to produce an area of paraesthesia covering the area of radiation of anginal pain. Stimulator had two settings- stronger for established pain, and weaker for prophylaxis (used at least two hours four times daily). Patients could switch the electrode on and off by using a magnet over a pulse generator located below the left costal arch.

    86% followed for 6 months
    Outcome notes:
    • symptoms not improved : using a questionnaire
    • non-fatal cardiac event : MI, angina or heart failure leading to hospital admission

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    symptoms not improved 6 months 10
    (19.6%)    		 9
    (17.0%)    		 13%
    (-96% to 62%)    		 2.63%
    (-12.2% to 17.5%)    		 38
    (NNT = 6 to infinity;
    NNH = 8 to infinity)
    death 6 months 7
    (13.7%)    		 1
    (1.89%)    		 86%
    (-8% to 98%)    		 11.8%
    (1.71% to 22.0%)    		 8
    (5 to 59)
    non-fatal cardiac event 6 months 7
    (13.7%)    		 7
    (13.2%)    		 4%
    (-155% to 64%)    		 0.52%
    (-12.6% to 13.6%)    		 190
    (NNT = 7 to infinity;
    NNH = 8 to infinity)

  • Both groups had fewer angina attacks and used less nitrate medication following surgery- there were no differences between the two groups.

    • Comments

    1. It is very likely that there are no long-term effects on myocardial ischemia after the SCS has been discontinued for 24 hrs.

    Citation

    1. Mannheimer C, Eliasson T, Augustinsson L-E, et al: Electrical stimulation versus coronary artery bypass surgery in severe angina pectoris. Circulation 1998; 97: 1157-1163
    Search Terms: from other articles noted in ACP Journal Club
    Contributor: Chris Ball and Clare Wotton, June 2000
    Reviewer: William Rhoton

    Clinical Question.
    Patient severe angina
    Intervention or Exposure spinal-cord stimulation surgery
    Comparison CABG
    Outcome improved symptoms, death