Patients with diabetes mellitus account for approximately 25% of the
nearly 1.5 million coronary revascularization procedures performed each year
in the United States and experience worse outcomes compared with nondiabetic
To summarize the current state of evidence comparing the effectiveness
and safety of coronary artery bypass graft (CABG) surgery and percutaneous
coronary intervention (PCI) in diabetic patients and to examine developments
that may affect future outcomes in this high-risk group.
Using the key terms diabetes mellitus, revascularization, coronary artery bypass, angioplasty, and coronary
intervention, we searched MEDLINE from 1985 to 2004 for all randomized
controlled trials (RCTs) comparing CABG surgery and PCI that reported outcomes
in diabetic patients. Bibliographies and the Web sites of cardiology conferences
were also reviewed. Studies comparing drug-eluting stents and bare-metal stents
were identified in a similar fashion. The literature was reviewed to identify
clinical measures that may impact revascularization outcomes in diabetic patients.
We identified 6 RCTs comparing CABG surgery and PCI in a total of 950
diabetic patients. A mortality benefit for CABG over balloon-only PCI has
been demonstrated in diabetic patients with multivessel coronary artery disease
but has not been clearly established against stent-assisted PCI or in high-risk
CABG patients. Use of glycoprotein IIb/IIIa receptor inhibitors has improved
survival in diabetic patients undergoing PCI. Restenosis after PCI in diabetic
patients has led to substantially higher repeat revascularization rates than
after CABG. The use of drug-eluting stents has led to dramatic reductions
in restenosis in diabetic patients. Ongoing RCTs comparing CABG and PCI using
drug-eluting stents in diabetic patients will clarify the impact of these
advances on outcomes.
There is a relative lack of data from RCTs specifically comparing CABG
surgery and PCI as currently practiced in diabetic patients. The mortality
advantage and decreased rates of revascularization seen with CABG in subgroups
from early trials may not be applicable in the era of drug-eluting stents,
glycoprotein IIb/IIIa inhibitors, and the latest medical therapies.