Previous CABG vs. angioplasty in diabetic patients with MI

The 1996 BARI study showed that showed that CABG reduced long term death rates by up to 50% in diabetics vs. a comparable group treated with angioplasty.

This study examined diabetic patients with acute myocardial infarction and asked whether mortality is higher in those treated previously with angioplasty as compared to those treated previously with CABG.

Patients who had been entered into the BARI trial were classified within three months into 641 with diabetes and 2962 without. Patients were assessed at 5 years for:

• death
• a history of Q wave myocardial infarction since entry into the study

All cause mortality at five years was significantly higher in diabetics:

• 20% mortality for diabetics
• 8% mortality for non-diabetics
  • p<0.001
• Q wave myocardial infarction incidence at five years was significantly higher in diabetics:
  • 8% for diabetics
  • 4% for non-diabetics
    • p<0.001
• In diabetic patients who suffered a Q wave myocardial infarction there was a highly significant reduced mortality in the patients previously treated with CABG vs. angioplasty:
  • relative risk of death for CABG group = 0.09
  • 95% confidence 0.03-0.29
• In diabetics patients who did not suffer a Q wave myocardial infarction there was a less pronounced protective effect of previous CABG vs. angioplasty:
  • relative risk of death for CABG group = 0.65
    • 95% confidence 0.45-0.94
• among non-diabetics patients CABG was not superior to angioplasty
• conclusions:
  • proportion of the protective effect of CABG surgery in diabetic patients is due to the greatly reduced mortality after myocardial infarction
  • CABG is also protective in diabetic patients who do not have a myocardial infarction
  • CABG is not superior to angioplasty in the non-diabetic population
    
    
• a collaborative analysis comparing the two treatments concluded that (2):
  • long-term mortality is similar after CABG and PCI in most patient subgroups with multivessel coronary artery disease, so choice of treatment should depend on patient preferences for other outcomes
  • CABG might be a better option for patients with diabetes and patients aged 65 years or older - mortality was found to be lower in these subgroups.

Reference:

• Detre, DM. et al.The effect of previous coronary-artery bypass surgery on the prognosis of patients with diabetes who have acute myocardial infarction. New Engl J Med 2000; 342: 989-97.
• Hlatky MA et al. Coronary artery bypass surgery compared with percutaneous coronary interventions for multivessel disease: a collaborative analysis of individual patient data from ten randomised trials. Lancet. 2009 Apr 4;373(9670):1190-7.