In patients with type 1 diabetes, coronary artery bypass graft (CABG) is associated with a lower risk of coronary heart disease mortality, myocardial infarction (MI) and repeat revascularization compared with percutaneous coronary intervention (PCI), according to research presented by Martin Holzmann, MD, PhD, on Aug. 26 at ESC Congress 2017 in Barcelona and simultaneously published in the Journal of the American College of Cardiology.

Previous studies demonstrated a lower risk of death among patients with diabetes treated with CABG versus PCI. However, none of the studies reported how many patients with type 1 diabetes were included. Current guidelines recommend CABG over PCI for the treatment of multivessel disease in patients with diabetes. The objective of this study was to determine whether patients with type 1 diabetes and multivessel disease benefit from CABG compared with PCI.

The study included all patients with type 1 diabetes who underwent a first multivessel revascularization with PCI or isolated CABG from 1995 to 2013 in Sweden. Patient data were retrieved from the SWEDEHEART register, the National Diabetes Register (NDR) and the Swedish National Patient Register. The primary outcome was all-cause mortality. The secondary outcomes were death from coronary heart disease, MI, stroke, heart failure (HF) and repeat revascularization.

A total of 2,546 patients with type 1 diabetes underwent a first multivessel revascularization (73 percent with PCI) during the study period. From 1995 to 1999, most patients received CABG (62 percent), but thereafter the rates of CABG declined and by 2010 to 2013 PCI was the treatment in 98 percent of patients.

During the mean follow-up of 10.6 ± 5.1 years, 53.3 percent of patients in the CABG group died compared with 44.6 percent in the PCI group. The absolute risk of death was higher after PCI vs. CABG at 1 year (5.0 vs. 0.7 percent), 2 years (8.3 vs. 1.2 percent), and 5 years (18.6 vs. 6.4 percent). The adjusted risk of death was similar with PCI vs. CABG (hazard ratio [HR], 1.14; 95 percent confidence interval [CI], 0.99-1.32). Patients in the PCI vs. CABG group had a greater risk of dying from coronary heart disease (HR, 1.45; 95 percent CI, 1.21-1.74).

Patients in the PCI vs. CABG group had greater absolute risks for MI, stroke, HF and repeat revascularizations. The adjusted risk was higher after PCI than CABG for MI (adjusted HR, 1.47; 95 percent CI, 1.21-1.77) and repeat revascularizations (adjusted HR, 5.64; 95 percent CI, 4.67-6.82). At 30 days, the stroke rate was 1.9 percent after CABG vs. 0.8 percent after PCI, but there was no difference in the long-term adjusted risk of stroke between the groups. The adjusted risk for HF was similar between the groups.

The investigators concluded that CABG should be the preferred strategy for multivessel revascularization in patients with type 1 diabetes, but cautioned that there were large differences in risks during the first year of follow-up, indicating large differences in risks at baseline between the PCI and CABG groups. “There is a need for clinicians and policy-makers to implement the findings from our and previous studies on which revascularization strategy should be preferred,” they wrote.

In a related editorial comment, Michael J. Domanski, MD, and Michael E. Farkouh, MD, MS, write that “no randomized trial has compared revascularization strategies exclusively in patients with T1DM, so this paper provides information in an essentially data-free zone.” They suggest the findings should help to inform practice and could help influence decision-making for revascularization in patients with T1DM.

Keywords: ESC Congress, ESC2017, Diabetes Mellitus, Type 1, Coronary Artery Disease, Coronary Artery Bypass, Percutaneous Coronary Intervention, Myocardial Infarction, Stroke, Heart Failure

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