NEW YORK (Reuters Health) - For patients with diabetes and complex multivessel coronary artery disease, the risk of repeat vascularization within one year is elevated 3-fold after percutaneous coronary intervention (PCI) compared with surgery, according to a subgroup analysis from the multinational SYNTAX study.
Otherwise, rates of serious outcomes at 12 months in diabetic patients were similar after coronary artery bypass grafting (CABG) and PCI with the Taxus Express paclitaxel-eluting stents.
The SYNTAX study was the first to compare CABG and PCI with Taxus for complex left main and/or 3-vessel disease in both diabetic and nondiabetic patients, Dr. Adrian P. Banning and co-authors note in the Journal of the American College of Cardiology for March 16.
The trial evaluated major adverse cardiac and cerebrovascular events in 1800 patients, with a piori stratification based on the presence or absence of medically treated diabetes and left main disease The CABG group consisted of 897 subjects overall (676 nondiabetics, 221 with diabetes), and the PCI group contained 903 subjects (672 nondiabetics, 231 with diabetes). Only patients taking oral antiglycemics or insulin were classified as diabetics; patients controlling the disease by diet only were included in the nondiabetic group.
The primary SYNTAX endpoint – a composite of death, stroke, and myocardial infarction -- was not met in the subgroup analyses. Thus, Dr. Banning, from John Radcliffe Hospital, Oxford, UK, and his colleagues say the results are “hypothetical and hypotheses generating only” and “should not necessarily dictate any change in current practice patterns.”
(In the overall SYNTAX analysis, however, patients treated with CABG had much lower rates of major cardiac or cerebrovascular events, or MACCE, at 1 year than those managed with PCI. See Reuters Health story posted February 18, 2009.)
In analyses restricted to diabetic patients, not only was there no difference between the CABG and PCI groups in rates of MACCE, but there was also no difference in rates of symptomatic graft occlusion or stent thrombosis.
There were, however, significantly higher rates of repeat revascularization with PCI in both diabetics (6.4% after CABG vs 20.3% after PCI, relative risk 3.18) and nondiabetics (5.7% vs 11.1%, respectively, RR = 1.94). The difference between diabetics and nondiabetics in the PCI group was significant.
Overall, the number needed to treat by CABG to avoid 1 major adverse cardiac or cerebrovascular event (driven primarily by repeat revascularization) was 9 for patients with diabetes and 31 for nondiabetic patients.
The researchers note that aggressive progression of diffuse disease in diabetics is likely to have a greater impact in the stented cohort versus the CABG group, in which distal grafts minimize disease progression in upstream proximal vessels.
They caution, however, that due to the complexity of participants’ coronary artery disease, these results should not be generalized to all patients with diabetes. Also, these results are early, with follow-up planned for 5 years.
They conclude, “These exploratory results may extend the evidence base” for paclitaxel-eluting stents in selected diabetic and nondiabetic patients with left main and/or 3-vessel disease.
In an editorial, Dr. Harold L. Dauerman, from the University of Vermont in Burlington, states, “At 1 year, there is no death penalty associated with multivessel PCI” in patients with diabetes, though that doesn’t preclude its appearance with longer follow-up.
However, he adds, “The use of (drug-eluting stents) fails to turn diabetic patients into nondiabetic patients,” given the higher risk of repeat revascularization with PCI.
He concludes that multivessel PCI is a viable general option for diabetics, while warning that PCI without drug-eluting stents has been shown to increase mortality and should not be avoided.
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