Loss of Glycemic Control in Diabetes Increases Stent Failure

PARIS — For the first time, there is compelling evidence that the degree of poor glycemic control in patients with type 2 diabetes is a relative risk factor for stent failure after a percutaneous coronary intervention (PCI).

In patients undergoing revascularization, diabetes has long been identified as an independent risk factor for stent complications, including stent failure, but this study demonstrates that the risk is dose-dependent, according to Irene Santos-Pardo, MD, Department of Cardiology, Södersjukhuset, Stockholm, Sweden. She presented the new evidence at the Congress of the European Association of Percutaneous Coronary Interventions (EuroPCR) 2024, which was simultaneously published in the Journal of the American College of Cardiology.

Santos-Pardo and her colleagues drew on multiple Swedish registries to analyze data from 24,111 patients with diabetes who received 29,029 stents. They found the risk for stent failure was 30% higher for those with an A1c level higher than the reference level of 6.1%-7.0%, after adjusting for a long list of variables that included body mass index, previous coronary disease and interventions, diabetes treatments, and PCI variables.

More significantly, they also found that each incremental increase in A1c carried a greater risk for stent failure. It was 25% higher among those with an A1c of 7.1%-8.0%, 30% among those ranging from 8.1% to 9.0%, and 46% among those ranging from 9.1% to 10.0%.

For those with an A1c greater than 10.1%, the increase risk dropped to 33%, but Santos-Pardo said this is likely explained by competing risks, including death.

These results remained remarkably consistent across analyses. There was no change in the relative risks when those treated with insulin were compared with those who were not. While the impact of poor glycemic control on the risk for stent failure was greater in patients younger than 65 years than in those who were older, the incremental relationship between degree of hyperglycemia and risk was the same.

In-Stent Thrombosis

The study identified several specific risks associated with higher A1c. The risk for in-stent thrombosis, for example, increased by 55% in those with an A1c of 9.1%-10.0%, which led Santos-Pardo to characterize thrombosis as a driver of stent failure associated with hyperglycemia.

The risk for death was also highest in those with an A1c greater than 10.0%. But the risk for myocardial infarction was not significantly different among the A1c stratifications.

There was a sign that low A1c may also increase the risk for stent failure. Those with an A1c below 5.5% had a 10% increase in risk, although it was not statistically significant.

A Known Risk

There are many mechanisms by which diabetes might increase the risk for adverse outcomes independent of elevated blood sugar. For example, the disease is associated with proinflammatory effects, hypertension, and adverse effects on other organs, such as the kidney, but Santos-Pardo emphasized that the risk from high A1c persisted even after a regression analysis allowed them to control for most of these factors.

“Achievement of good glycemic control is of substantial importance for avoiding stent failure” regardless of other variables, she said.

“Tight glycemic control is already recommended in patients with diabetes who undergo PCI because we know this is one way to improve outcomes,” said Antonio Greco, MD, an interventional cardiologist at the University of Catania in Catania, Italy. “I think the unique contribution of this study is the detection of meaningful increases in risk for each incremental increase in HbA1c.”

He added the work draws attention to the importance not only of tight control but also of using antidiabetic therapies that are associated with cardiovascular benefit, such as glucagon-like peptide 1 agonists and sodium-glucose cotransporter 2 inhibitors.