Which of the following is a risk factor for restenosis?

• A. Diabetes mellitus
• B. Hyperlipidemia
• C. Chronic total occlusion
• D. Smoking

Answer: (A)

Diabetes mellitus is a major driver of restenosis because it fundamentally alters how the vessel heals after injury. Hyperglycemia promotes vascular smooth muscle cell proliferation and migration, increases inflammatory signaling, and enhances deposition of extracellular matrix, all of which accelerate neointimal hyperplasia—the tissue growth that narrows the artery after PCI. This effect is especially pronounced after stent placement, where diabetics have higher restenosis rates, even though drug-eluting stents lessen this risk compared with bare-metal stents.

Hyperlipidemia, while contributing to progression of atherosclerosis and longer-term lumen loss, is less directly tied to the neointimal proliferation that causes restenosis. Chronic total occlusion describes a complex lesion that makes the procedure more challenging and can influence outcomes, but it’s a lesion characteristic rather than a systemic risk factor. Smoking increases inflammatory and thrombotic activity and can raise restenosis risk, but the influence is typically smaller than the strong proliferative milieu driven by diabetes.