Introduction: Current ACC/AHA guidelines provide a Class I recommendation that patients with diabetes and symptomatic multivessel coronary artery disease be treated with coronary artery bypass surgery (CABG). However, these patients are heterogeneous in terms of the risk and benefit associated with CABG. We hypothesized that a risk score can be developed from the CABG arm of BARI 2D to identify low-risk patients with diabetes and multivessel CAD in whom CABG can be safely deferred.
Methods: A risk score for the composite outcome of death, myocardial infarction (MI) and stroke was developed using age, history of CHF, history of hypercholesterolemia, history of CVA/TIA, serum creatinine, insulin use, myocardial jeopardy index, and HbA1c data from the OMT group then validated in the CABG group. Event-free survival curves were compared among three groups: CABG, patients who crossed over from OMT to CABG/PCI within 12 months of randomization and OMT alone.
Results: Among the 763 patients in the CABG strata of BARI 2D, 385 were randomized to OMT and 378 to CABG. Among the 385 patients randomized to OMT, 72 crossed over to CABG/PCI within 12 months of randomization. Patients randomized to OMT, CABG and those who crossed over with a risk score less than the median experienced similar rates of event-free survival at 5 years from death, MI, or stroke (77%, 83%, 80%, respectively; p=0.51). Patients who crossed over with a high risk score suffered worse rates of event-free survival than the OMT alone or CABG groups (41%, 65%, 73%, respectively; p<0.0001).
Conclusion: Low-risk patients with diabetes and multivessel CAD in whom CABG can be safely deferred can be identified by a novel risk score. Among those with high risk scores, patients who cross over from OMT to revascularization suffered worse outcomes indicating that all high-risk patients should continue to undergo CABG.