CABG outperforms PCI in patients with type 1 diabetes

Coronary artery bypass grafting (CABG) demonstrates favorable results when compared to PCI in patients with type 1 diabetes (T1D), according to a new study in the Journal of the American College of Cardiology.

After a mean follow-up of 10.6 years, PCI patients were found to have a greater than fivefold risk of repeat vascularization, a 47 percent greater risk of MI and a 45 percent increased risk of death from coronary heart disease. The differences in all-cause mortality, stroke and heart failure weren’t statistically significant.

The benefit of CABG over PCI in diabetic patients had previously been proven, the study’s authors noted, but the proportion of type 1 patients was never reported.

Thomas Nyström, MD, with the division of internal medicine at Södersjukhuset, Stockholm, led a team of researchers who analyzed all patients with T1D who underwent a first multivessel revascularization in Sweden from 1995 to 2013. A total of 1,863 patients underwent PCI, while 683 had CABG.

Patients treated with PCI were older, more often women, had a longer duration of diabetes and were more likely to have had previous MIs and strokes. The authors attempted to adjust for those variables but suggested a careful interpretation of their data nonetheless.

“We found that CABG was associated with a lower risk of coronary heart disease mortality, myocardial infarction, and repeat revascularization compared with PCI,” Nyström and colleagues wrote. “Even if our findings indicate that CABG should be the preferred strategy for multivessel revascularization in patients with T1D, our findings should be interpreted with some caution because of the observational nature of the study, and maybe more importantly, the large differences in risks in the first year of follow-up, indicating that there were large inherent differences in risk at baseline between the PCI and CABG groups.”

Another limitation was the increased use of PCI versus CABG over the length of the trial. Sixty-five percent of the patients who received CABG did so within the first six years, or one-third, of the study period.

In a related editorial, a pair of Canadian doctors wrote the nature of CABG—its bypass effect—is why it continues to show lower recurrence rates in patients with diabetes or aggressive coronary artery disease.

“The overall risk that an occlusive event will cause myocardial damage is the sum of the risk at each point along the entire artery,” wrote Michael J. Domanski, MD, of Toronto General Hospital/Mount Sinai Hospital; and Michael E. Farkouh, MD, of the University of Toronto.

“CABG removes large segments of the artery that would have added to the total risk of necrosis by an occlusion.”