Unstable angina: by-pass surgery for three vessel disease or moderate ejection fraction reduced mortality.

Clinical bottom line (level 2b)

  1. No more patients with unstable angina who had bypass surgery compared with medical therapy, lived longer or had fewer hospital admissions. The effect on non-fatal MI was unclear.
  2. Fewer high risk patients (three vessel disease or ejection fraction <58%) died with surgery (NNT = 9 at 8 years) .
  3. More low risk patients (one or two vessel disease or ejection fraction 58% or more) died with surgery (NNH = 6 at 8 years) .
Luchi et al: New England Journal of Medicine 1987; 316: 977-984
Parisi et al: Circulation 1989; 89: 1176-1189
Sharma et al: American Journal of Cardiology 1994; 74: 454-458
Expires July 2003

The study

Unblinded ?concealed quasi-randomised trial without intention-to-treat
Setting: eleven Veteran Association Hospitals

468 patients (aged mean 56 years, 100% male) unstable angina (present for >2 months) with worsening symptoms (increase in severity of frequency) or appearance of angina at rest within eight weeks)

Excluded if
  • 70 years old or more
  • acute myocardial infarction within three months
  • atypical chest pain
  • onset/ change in angina >8 weeks ago
  • angina pain absent within 10 days of admission
  • negative exercise tolerance test
  • on coronary angiogram- normal coronary arteries or no critical stenosis; diffuse coronary artery disease, lesion in left artery, ejection fraction <30%, complication of coronary arteriography (MI, CVA, death)


    • Note:
  • Patients were stratified for type of unstable angina and LV function before randomisation.
  • High risk group- three vessel disease or ejection fraction <58%
  • Low risk group- one or two vessel disease and ejection fraction 58% or more


    • Control Group: (n = 237, 237 analysed): medical therapy- nitrates or propranolol or both. Aspirin or dipyridamole were optional. Heparin or warfarin not allowed
    Experimental Group: (n = 231, 231 analysed): coronary artery bypass grafting plus medical therapy
    All patients were encouraged to stop smoking, diet and lose weight, and exercise regularly.
    98% followed for 8 years

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    death 5 years 192
    (81%)    		 194
    (84%)    		 -4%
    (-13% to 5%)    		 -2.98%
    (-9.86% to 3.90%)    		 -34
    (NNT = 10 to infinity;
    NNH = 26 to infinity)
    non-fatal MI 8 years 42
    (17.7%)    		 36
    (15.6%)    		 12%
    (-32% to 41%)    		 2.12%
    (-4.63% to 8.86%)    		 47
    (NNT = 22 to infinity;
    NNH = 11 to infinity)
    new hospitalisations 8 years 175
    (73.8%)    		 155
    (67.1%)    		 9%
    (-2% to 19%)    		 6.70%
    (-1.55% to 15.0%)    		 15
    (NNT = 65 to infinity;
    NNH = 7 to infinity)

    high risk patients
    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    death 8 years 53
    (35.3%)    		 33
    (24.1%)    		 32%
    (1% to 53%)    		 11.2%
    (0.74% to 21.7%)    		 9
    (5 to 140)

    low risk patients
    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    death 8 years 14
    (16.8%)    		 29
    (32.2%)    		 -93%
    (-239% to -10%)    		 -15.5%
    (-28.1% to -3.00%)    		 -6
    (-33 to -4)

    Comments

    1. Out-moded therapy- not all patients received aspirin, beta-blockers or calcium channel blockers all of which may have decreased mortality for both groups.
    2. No women in the study.
    3. Over 8 years, 45% of medical patients required surgery for angina controlled by medical therapy.

    Citation

    1. Luchi RJ, et al: Comparison of medical and surgical treatment for unstable angina pectoris: results of a Veterans Administration Cooperative Study. New England Journal of Medicine 1987; 316: 977-984
    2. Parisi AF, et al: Medical compared with surgical management of unstable angina. 5 year mortality and morbidity study in the Veterans Administration Study. Circulation 1989; 89: 1176-1189
    3. Sharma GV, et al: Identification of unstable angina patients who have favourable outcome with medical or surgical therapy (eight-year follow-up of the Veterans Administration Co-operative Study). American Journal of Cardiology 1994; 74: 454-458
    Contributor: Nick Shenker and Chris Ball, July 2000
    Reviewer: Jean Legare

    Clinical Question.
    Patient unstable angina
    Intervention or Exposure CABG and medical therapy
    Comparison medical therapy alone
    Outcome death