FROM THE ESC CONGRESS 2017
In patients with type 1 diabetes in need of multivessel revascularization, coronary artery bypass graft (CABG) may be a better choice than percutaneous coronary intervention (PCI), according to results from a new comparative study presented at the annual congress of the European Society of Cardiology by Martin J. Holzmann, PhD, of the Karolinska Institute, Stockholm.
The two procedures had similar mortality rates, but PCI patients fared worse with respect to mortality due to myocardial infarction and several cardiovascular outcomes.
The findings were published simultaneously in the Journal of the American College of Cardiology (2017. doi: 10.1016/j.jacc.2017.07.744 ). The results suggest that CABG may be superior, but the study carries an important caveat: Some patients may have undergone PCI because they were too sick to undergo CABG, which could have skewed the results in favor of CABG. The authors adjusted for this possibility, but the potential for unrecognized confounders remains.
Previous studies had also suggested better outcomes with CABG than with PCI, but they lumped together patients with type 1 and type 2 diabetes, while the current study focused only on patients with type 1 diabetes.
The study included patients in Sweden with type 1 diabetes who underwent CABG (683 patients) or PCI (1,863 patients) between 1995 and 2013. During follow-up, 44.6% of patients in the PCI group died, compared with 53.3% in the CABG group. After adjustment for between-group differences, however, there was no significant difference in mortality risk between the two groups.
However, assessments of cause-specific mortality told a different story. Subjects in the PCI group had a greater risk of death from coronary artery disease (hazard ratio, 1.45; 95% confidence interval, 1.21-1.74).
Subjects in the PCI group were also more likely to suffer myocardial infarction (HR, 1.47; 95% CI, 1.21-1.77) and were more than five times more likely to undergo repeat vascularization (adjusted HR, 5.64; 95% CI, 4.67-6.82). The CABG group had a higher 30-day stroke risk (1.9% vs. 0.8%), but there was no difference in long-term risk.
The two groups had similar risks of hospitalization for heart failure.
The researchers noted a large difference between the two groups with respect to risk during the first year of follow-up, which suggests that some patients underwent PCI because they were too ill to undergo CABG. This limitation is also suggested by the greater proportion of previous stroke, heart failure, active cancer, and end-stage renal disease in the PCI group. The researchers adjusted for these differences, but it remains possible that there were residual confounders.
No source of funding was disclosed. One of the authors has received consultancy honoraria from Actelion and Pfizer. Dr. Domanski and Dr. Farkouh report no relevant financial relationships.
