Randomized trial of insulin versus usual care in reducing restenosis after coronary intervention in patients with diabetes. the STent Restenosis And Metabolism (STREAM) study

BACKGROUND: Diabetes status is an independent marker of restenosis after percutaneous coronary intervention (PCI). Previous studies suggest that metabolic abnormalities associated with diabetes increase stent restenosis by promoting intimal hyperplasia. Preclinical studies have indicated that insulin therapy reduces intimal hyperplasia. The objective of this study was to determine whether insulin-mediated glucose lowering reduces in-stent restenosis in patients with diabetes undergoing PCIs. METHODS: We conducted a prospective, randomized, multicenter, open-labeled study with blinded outcomes. Patients were randomized 1:1 to daily bedtime subcutaneous NPH insulin (Novo Nordisk) versus usual therapy with oral hypoglycemic agents. The main outcomes were change in volume of intimal hyperplasia within the stent measured by intravascular ultrasound and late lumen loss by quantitative coronary angiography at 6 months post-PCI. RESULTS: Seventy-eight patients (36 insulin, 42 usual care) were randomized. Eight patients in each group received drug-eluting stents. The insulin group achieved greater reductions in both glycosylated hemoglobin A1c (mean±S.D.) (insulin: 8.0%±1.2% to 6.7%±0.7% vs. control: 7.5%±1.2% to 7.1%±1.0 %, P=.0038) and fasting glucose (insulin: 9.3±3.8 to 5.8±1.7 vs. usual care: 8.4±2.4 to 7.7±2.0 mmol/l, P<.0001). There were no hypoglycemic events. At 6 months, there were no significant differences in either intravascular-ultrasound-determined neointimal volume (insulin: 41.2±38.9 vs. usual care: 48.4±40.2 mm(3), P=.33) or late lumen loss by angiography (insulin: 1.29±0.74 mm vs. usual care: 1.02±0.71 mm, P=.17). CONCLUSIONS: Addition of a single bedtime dose of insulin in patients with diabetes does not influence in-stent restenosis.