DCB in Diabetes Show Promising Long-term Outcomes: BASKET-SMALL 2

Diabetes puts patients being treated for small-vessel CAD at higher risk of developing MACE over the long term, but drug-eluting stents and drug-coated balloons perform similarly, data from the BASKET-SMALL 2 trial show.

The findings add context to the main BASKET-SMALL 2 study, which showed that DCB were noninferior to DES for MACE in an all-comers population with an indication for PCI (ACS, stable angina, or silent ischemia) in small arteries. Researchers led by Jochen Wöhrle, MD (Medical Campus Lake Constance, Friedrichshafen, Germany), say the new subgroup analysis “demonstrates the sustained efficacy and safety of DCBs in diabetic patients with de novo lesions of small coronary vessels up to 3 years compared with DES.”

The rate of MACE (the composite of cardiac death, nonfatal MI, and TVR) was 13.0% with DCB and 11.5% with DES (P = 0.43) in the nondiabetic patients at 3 years. Corresponding MACE rates in the diabetic population clocked in much higher but again were not statistically different, at 19.3% with DCB and 22.2% with DES (P = 0.51).

This BASKET-SMALL 2 analysis “supports the claim that we need to follow patients longer, particularly those with diabetes, because there are late events,” said Michael E. Farkouh, MD (University of Toronto, Canada), who commented on the study. “It suggests that there's some promise for the drug-coated approach, maybe even some benefit. . . . But there are differences between those with diabetes and those without diabetes, suggesting that well-powered trials need to be done in each of those groups of patients.”

By studying these two groups together, Farkouh added, “potential effects could get drowned out. It’s a small study and it’s important, but it shouldn’t be overinterpreted. It’s not going to change practice.”

Less TVR in Diabetic Population With DCB

BASKET-SMALL 2 was conducted at 14 centers in Germany, Switzerland, and Austria. The open-label, noninferiority trial included 758 patients with small de novo coronary lesions that were at least 2 mm but < 3 mm in diameter. Patients were randomized to the SeQuent Please paclitaxel-coated balloon (B. Braun Melsungen) or one of two DES. The comparator was the paclitaxel-eluting Taxus Element (Boston Scientific) initially and then later the everolimus-eluting Xience stent (Abbott). At 1 year, the MACE rate was 7.33% in the DCB group and 7.45% in the DES group, meeting criteria for noninferiority (P = 0.0152).

The prespecified analysis, published today in JACC: Cardiovascular Interventions, compared the 252 diabetic patients with the 506 who did not have diabetes. As with the MACE rates, the individual endpoints of cardiac death and nonfatal MI were higher in the diabetic cohort than the nondiabetic cohort, though similar for the DCB versus the DES. What was statistically different, however, were TVR rates, which favored the DCB over the DES in the diabetic patients (9.1% vs 15.0%; P = 0.036) but showed no difference in the nondiabetic population (8.8% vs 6.1%; P = 0.16).

In an email, Wöhrle said possible explanations for the lower TVR in diabetic patients “might be that with DCB, there is no permanent metallic frame or polymer-inducing inflammation, neoatherosclerosis, and neointimal proliferation; this is potentially of special interest since strut size in DES is usually the same for small vessels or normal-sized coronary arteries.” He added that the greater tendency toward stent thrombosis when DES are used in small- versus normal-sized coronary arteries could also play a role in the findings.

Writing in an accompanying editorial, Manel Sabaté, MD, PhD (Hospital Clinic, Barcelona, Spain), says the study “sets the foundation for an expansion of the indication for DCB in daily practice.” However, he notes that assessing vessel size angiographically, as was done in BASKET-SMALL 2, is an important study limitation. It can be “misleading owing to the presence of diffuse disease with different degrees of coronary remodeling (expansive vs constrictive) and a more advanced atherosclerotic process. The use of intracoronary imaging could have been helpful in this context,” he asserts.

Sabaté further points out that 28% of the DES cohort was treated with first-generation devices, which are associated with worse long-term outcomes than newer-generation DES.

Farkouh agreed that those limitations of the study are important, but reiterated that the analysis is too small to draw firm conclusions that would be generalizable to diabetic patients with small-vessel CAD who require PCI. As for the TVR, he said while “it's suggestive that maybe in the diabetic group to prevent repeat revascularization a coated balloon may be the best approach,” the issue is far from settled.